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WELCOME IN THE WORLD OF “TRANSPARENCIES 2.0”

WE LCO ME (new edition on the occasion of the 40th anniversary of Bruni Glass and of Expo 2015)

Over many years of activity, many customers have raised questions or asked clarifications about glass containers for food products.

“Transparencies 2.0” is a collection of fun facts, information and technical details that aim at giving an answer to those questions and at showing, at least partially, the peculiarities of those containers that are so common and to give explanations about the material they are made up of. The different “chapters” of “Transparencies 2.0” can be of interest both for end users (for their information) and for professional users that often meet difficulties or doubts that are not so easy to clarify. “Transparencies 2.0” is mainly a descriptive book and not a teaching tool. Nevertheless it is worth saying that the information here contained represents the basis that the university students of Industrial Design have used to learn and still use to develop new container shapes for the international contest called “Bruni Glass Design Award”. www.bruniglassdesignaward.com

Gino Del Bon


Progetto Thunder - by Alfredo Inzani, School of Design, Politecnico di Milano, 2013 Millennium Project.


INDEX

1. SOME QUESTIONS ABOUT GLASS

page 7

2. LOOKING INTO GLASS

page 39

3. DESIGNING AND CREATING A BOTTLE

page 97

TRASP AREN CIES 4. A SHOWCASE FOR YOUNG DESIGNERS

page 127

5. DICTIONARY OF GLASS DEFECTS

page 143

6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

page 175


1

SOME QUESTIONS ABOUT GLASS

SOME QUE STI ONS 1. ENVIRONMENT RECYCLING - HYGIENE

page 8

2. FUN FACTS HISTORY - MATERIAL - MARKET

page 15

3. TECHNIQUES EXPLAINED FOR THE MOST CURIOUS READERS

page 27


1. SOME QUESTIONS ABOUT GLASS

ENVIRONMENT RECYCLING - HYGIENE

1. WHY IS GLASS CONSIDERED TO BE THE MOST HYGIENIC MATERIAL FOR PACKAGING PURPOSES?

Because glass is completely neutral to its content: it neither releases anything nor absorbs anything from the product (taste, odor or aroma). It has a high chemical resistance, and is waterproof and gas-proof. It can be easily sterilized, has antistatic properties and does not pollute the environment. It is completely indifferent to climate variations.

2.

SINCE IT IS THE RESULT OF AN INDUSTRIAL OPERATION, CAN GLASS HAVE INTERNAL IMPURITIES? IF SO, HOW CAN IT BE CONSIDERED TO BE THE MOST HYGIENIC MATERIAL?

It is important to distinguish between glass purity (the raw material melts at about 1500°C, while the shaping of the container takes place at about 900°C and these temperatures “purify” everything) and its overall hygienic quality, which depends firstly on how the container is packed at the glass factory and then on how it is stored and used later by the food packing company. Packaging processes - if properly carried out - normally ensure maintenance of the same hygiene conditions that apply during the production process itself. So if we are talking about “glass” as a material, it is hygienic by definition, but if we are talking about glass containers (bottles or jars), the hygienic qualities depend on how the container is used.

3. HOW MUCH RECYCLED GLASS SHOULD BE USED IN PRODUCTION?

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There is no technically fixed quantity. Cullet can be used as a support to the melting of the raw materials since it melts at a lower temperature and this offers significant economic and environmental advantages (less energy consumption). For extra-flint glass in particular, the quantity of glass cullet is kept as low as possible (10%) in order to avoid impurities appearing in the recycled material. Another solution is for the producer to use cullet exclusively from their own recycled product. Some glass factories that produce colored glass can use 60% or more of cullet since any color impurities in the cullet will not have a significant impact on the final result. It is also possible to manufacture new containers using only cullet, but in this


1. SOME QUESTIONS ABOUT GLASS

case it is important to adopt special strategies to keep complete control of the material in order to ensure the homogeneity of the molten materials.

4. WHAT COLOR IS THE FINAL RECYCLED GLASS PRODUCT, SINCE GLASS OBJECTS ARE THROWN INDISCRIMINATELY INTO GLASS BANKS REGARDLESS OF THEIR COLOR?

As mentioned in the previous answer, recycled glass of mixed colors is generally used to produce dark glass (green, antique green or yellow). Cullet (crushed and mixed) is used in the normal mixture of raw materials, with the addition of colorants that guarantee a uniform final result. Remember that melting takes place at over 1500°C and at this stage there is a viscous, perfectly homogeneous and purified mixture.

5. IS IT POSSIBLE TO DETECT THAT OBJECTS ARE MADE OF RECYCLED GLASS AT THE MOMENT OF PURCHASE?

No. When “cullet” is melted, it returns to its original purity as if it was “new glass”.

6. IS IT POSSIBLE TO RECYCLE AN OBJECT WHICH IS ALREADY A PRODUCT OF RECYCLING?

This operation can be repeated indefinitely; a 600 gr container will produce another container of the same weight without any loss. The original “mineral” does not change: the process of melting to the semi-liquid form is repeated (some people would define glass as a highly viscous liquid), the shape is changed, it solidifies as it cools and is then used again.

7. WHO COLLECTS GLASS FOR RECYCLING AND WHO USES IT? WHY?

Glass is collected by companies appointed by the individual municipalities. The collectors treat the glass cullet in special industrial plants that wash it, break it into very small pieces and separate off the impurities. The recycled glass is then sold to glass factories that mix it in with the batch formula.

8. IS GLASS “BIODEGRADABLE”? WHAT IMPACT DOES IT HAVE ON THE ENVIRONMENT?

No. Glass is a mineral and the labels on glass containers generally state “please dispose of responsibly”. Over time, glass will tend to “return to sand”, especially if it is thrown away on beaches, in the sea or wherever it may be repeatedly moved by natural elements.

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1. SOME QUESTIONS ABOUT GLASS

9. WHY ARE GLASS WATER BOTTLES RETURNED AND HOW ARE THEY RE-USED?

This is a question of relative cost, balancing the cost of water with the cost of the glass bottle, as these are both “low cost” items. Obviously it is necessary to take into account the cost of returning the bottle to the filling plant, as well as the cost of the necessary processing before it can be re-used: such processing is quite complex in terms of equipment and water consumption for washing, in order to ensure the completely hygienic condition of the bottle independently from the use previously made of it.

10. WHAT ARE THE ADVANTAGES OF GLASS COMPARED TO PLASTIC?

If you ask a “glass-manufacturer” this question, you’ll immediately get a smile of satisfaction. Glass is the only material which combines qualities that make it suitable for containing food while respecting the environment at the same time: it is waterproof and gas-proof, neutral (physically and chemically), inviolable and totally recyclable.

11. WHO IS IN CHARGE OF MONITORING THE HYGIENE OF THE GLASS CONTAINER?

See questions 2, 12 and 32. Basically, there is no guarantee that bottles and jars that come from a “Glass factory” are totally clean as if they had just been manufactured and packed. In fact, they are kept in warehouses for a while and for this reason it is advisable - before using them - to carry out a visual or mechanical inspection to ensure there are no impurities extraneous to the glass. These operations are now universally carried out, since they are also required by current legislation (HACCP - Hazard Analysis and Critical Control Points).

12. IF GLASS CONTAINERS SHOULD BE “CLEANED” BEFORE THEY ARE USED BY THE FOOD INDUSTRIES, WHAT IS THE MOST EFFICIENT METHOD IN TERMS OF HYGIENE?

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Glass containers arrive at the end of the uninterrupted production chain clean and packaged. Before using the container, the filling company must ensure that no internal contamination has occurred during storage and unpacking. A washing or blowing procedure is generally adopted on the production line. The blowing procedure - which is the most commonly used - is carried out by a machine placed in between the de-palletizer and the product filler which blows air forcefully into the upside down container. In this way the combination of air pressure and gravity together eliminate any impurities which may have been introduced during the storage or unpacking phases.


1. SOME QUESTIONS ABOUT GLASS

GLASS ENDLESS RECYCLING

2 1 3 5

1. Glass containers used in everyday life are thrown into bottle banks or collected by a door-to-door service. 2. The collected glass is delivered to treatment plants where all foreign elements are detected and separated (i.e. crystal, ceramics and other waste) using special optical and electronic machines as well as manual sorting. The result of this process is the Secondary Raw Material “SRM” which is ready to be recycled in the glass factory furnace. 3. The glass batch is melted at 1500°C in the glass factory furnace, and is then poured into molds on forming machines

4 to create a new container. This new bottle or jar is cooled down and passed on to the “cold area” to undergo on-line quality control and packing. The new glass container is now ready to be delivered to the user companies. 4. In the bottling plants, the new glass container is filled with different products and sent to the sales network. 5. The bottles and jars have been brought back to life and are on the supermarket shelves again, filled with different products. And everything starts again. The completed glass recycling process starts its virtuous economic circle again.

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GLASS’ FALSE FRIENDS Glass cullet coming from the differentiated collection is used to obtain “hollow glass”, that’s to say the material used to manufacture glass containers at industrial level. This is why differentiated collection of glass is particularly addressed to the recycling of the same material type (pots and bottles).

STONES, ROCKS AND INERT MATERIALS

CRYSTAL OBJECTS

TV AND COMPUTER SCREENS

MIRRORS

WINDOW GLASSES

NEON TUBES

BULBS

CERAMICS

MEDICINE BOXES

GLASS-CERAMIC CONTAINERS

All the other glass types which are commonly found in households cannot be thrown in the same glass banks for glass collection because: • Glass

for windows and mirrors (obtained through the float process) can be coupled with silver-based varnish (mirrors) and can have chemically-treated surfaces. • Pyrex glass are produced with boron-based glass (baking dishes, sanitary ware, pharmaceutical products...). Generally have a chemical composition which is not compatible with the glass for the production of pots and bottles. • Glass used in electric/electronic appliances can contaminate furnaces with metal scraps (bulbs, screens…). • Crystal glasses because they contain lead. • Ceramics as well can cause problems to furnaces because they melt at a higher temperature. All these different materials can be considered as “Glass false friends” as far as our recycling is concerned: if they enter the furnaces used for mechanical hollow glass production they alter the ordinary glass melting process. The ideal glass collection should be made also according to its color, because glass of the same color generally show similar chemical-physical properties.

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PRODUCTION CYCLE

PRODUCTION CYCLE

OF A NEW BOTTLE

OF A RECYCLED BOTTLE

RAW MATERIALS

GLASS CULLET

sand soda

calcium carbonate

others

1500째

350 gr

saving of raw materials environmental protection

energy saving -100째 reduced gas emissions

same final weight

1400째

350 gr

CoReVe (the Consortium of Glass Recycling) estimates that 1.64 million tons of glass was recycled in the year 2014 in Italy, corresponding to 73% of total glass use. This brings great benefits to the community in terms of reduced impact on the environment, reduced emissions from melting furnaces and reduced consumption of natural resources. In the last 9 years, increased education and awareness among citizens have enabled a continual growth in the collection of glass cullet: this is a good sign for our future and for this material as well.

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ANNOTAZIONI

Conveyor belt in the recycled glass furnace.

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1. SOME QUESTIONS ABOUT GLASS

FUN FACTS HISTORY - MATERIAL - MARKET

13. WHY DOES A WHITE FILM SOMETIMES APPEAR ON GLASSES AND BOTTLES? IS THE PRODUCT THEY CONTAIN HARMFUL?

The cause of this white film is the humidity that is present in many environments and that creates a thin film on the surface of the containers. This film tends to draw out alkalis (sodium and calcium) from the surface of the glass, increasingly over time, until the contact liquid has completely evaporated. The resulting cloudy look is caused by the formation of carbonates due to the presence of CO2 in the air. It is usually enough to wash the glass or fill it and this film immediately disappears. It is important to note that this is just an “aesthetic” defect that doesn’t affect the use of the container and doesn’t cause any damage to the product inside. If glasses are unused for a long time and are kept in damp environments (in holiday homes for example) or after prolonged use, this process of extraction can become almost irreversible, with the accumulation of large quantities of insoluble calcium carbonate. This may result in a cloudy, rough surface caused by micro-abrasions and insoluble calcium deposits (a defect that is visible but harmless in terms of health).

14. WHY DOES HOT WATER CAUSE GLASS TO BREAK?

It is not the hot water that breaks the glass, but the sudden change in temperature, causing internal stress to be exerted on the material; if these changes occur suddenly, they create internal tension that leads to the breakage of the container. Glass is a bad heat conductor (see page 47) and therefore it does not tolerate excessive changes in temperature. Normally it can tolerate a variation of 45°C, so if, for example, it is necessary to reach the temperature required for pasteurization, 90°C, it is necessary to gradually increase the temperature of the environment where the container is situated. This method will prevent any problems even with the sterilization process, which reaches 130°C. It is necessary to use an even more gradual procedure for containers of a particular shape (jars with handles, sharp edges, extra large containers, etc.).

15. CAN GLASS CONTAINERS BE FILLED WITH HOT PRODUCTS AS WELL?

Yes, they can. For instance fruit jams are poured into glass pots at about 85°C. The problem is the difference between the temperature of the glass and the temperature of the product.

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Glass containers should be adequately “acclimatized”: it is recommended that they are not moved from the warehouses (that are generally unheated) directly to the filling plant. Careful attention should also be paid to the subsequent heat treatments when the containers are sealed (pasteurization and sterilisation), since these treatments influence the internal pressure.

16. WHAT IS THE “PICURE” (“PUNT”) USED FOR?

The “picure” (“punt”) was originally used to collect wine sediment. Today it is used to guarantee better resistance to pressure for sparkling wine or fizzy drinks or for aesthetic reasons linked to tradition.

17. WHAT IS THE DIFFERENCE BETWEEN COSMETIC GLASS AND GLASS FOR FOOD PRODUCTS?

The difference lies essentially in the use of specific raw materials in the mixture which tend to favour products that enhance “shine” (by using barium for example) rather than the mechanical features. In cosmetic packaging, special steel is used for the molds, in order to increase the glossy finish of glass containers.

18. WHEN WAS GLASS FIRST USED AS AN INDUSTRIAL PACKAGING MATERIAL?

It has been used since about 1600 onwards, but real industrial production began later, see page 42.

19. WHAT ARE THE MAIN FEATURES THAT DIFFERENTIATE SPECIAL BOTTLES FROM STANDARD BOTTLES?

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There isn’t any real classification in this respect. A standard bottle is one that is usually manufactured by a glass factory and that can be used by many different customers. It is generally produced in large quantities compared to the average production of a glass factory. Special bottles may refer to those with a particular shape, not square or round, but may also refer to those designed especially for a particular customer and sold exclusively to that customer. From the point of view of the technological production, there is absolutely


1. SOME QUESTIONS ABOUT GLASS

no difference between these two articles, but special bottles always require a particular expertise when the production starts, in printing brand names, dealing with irregularities in the shape or creating a heavy base, or because they are unstable on the conveyor belts.

20. HOW DO YOU GET COLORED GLASS?

The color comes from natural chemical elements which are added to the raw material mixture. Cobalt for blue, selenium for pink, graphite and pyrite for dark yellow (amber), chromium for green (see page 46).

21. WHAT DOES BLUE GLASS HAVE THAT IS NOT PRESENT IN CLEAR OR GREEN GLASS?

Basically just a different use of colorants. For instance cobalt is used instead of the chromite in green glass. Colorants provide filtration ability and protection from light, which is lowest in clear glass, slightly higher in blue and more intense in the green. Take a look at page 178.

22. WHY IS BLUE GLASS EXCLUSIVELY PRODUCED IN “COLOR CAMPAIGNS”?

This is due to the fact that the quantities of glass required by the market in this color, with the various different types of container and the different geographical areas, cannot justify continuous production.

23. WHAT ARE THE MAIN COMPONENTS OF GLASS?

The main components of the glass batch are: (sand with particular features), which is the glazing element; • soda, which is the melting element; • calcium carbonate, which is the stabilizer (see page 46). • silica

24. WHY DO “ANTIQUE GREEN” BOTTLES OFTEN SHOW SLIGHT DIFFERENCES IN COLOR?

Because each factory uses different raw materials. At first, the “antique” color was patented both in the color and the name. Because of its great commercial success, many factories decided to launch similar products using different names and with slightly different raw materials. The weight of the bottle, or rather the thickness of the glass, can also lead to differences in color.

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1. SOME QUESTIONS ABOUT GLASS

25. AT WHAT TEMPERATURE DOES GLASS “BREAK”?

None of the temperatures generally used in daily life cause glass to break. Glass may break at low temperatures, but this is because the contents freeze and their expansion causes the glass to crack (if the cap does not come off). Hot temperatures can cause glass to break when the bottle is subject to excessive thermal variations (see questions 14 and 15). On the other hand, if a glass container is placed on a very hot source of heat (500°C for example), it can gradually lose its shape and change from a permanent solid form to a plastic state.

26. WHY ARE WINE BOTTLES ALWAYS MADE OF DARK GLASS WHILE TOMATO SAUCE BOTTLES ARE ALWAYS MADE OF CLEAR GLASS?

In the case of tomato sauce, the visibility of the product (mainly the color) is considered to be important for aesthetic reasons. Dark glass is often used for wine bottles in order to protect the product from the light, but also for traditional and aesthetic reasons, and of course, clear glass or light green bottles are often used to bottle wine.

27. WHY DO SOME BOTTLES BOUNCE OFF THE GROUND WITHOUT BREAKING AFTER FALLING FROM A HEIGHT, WHILE OTHERS SHATTER WITH THE SLIGHTEST OF KNOCKS?

Whether a glass container breaks or not depends not only on the type of impact but also on the thickness and distribution of the glass as well as the level of annealing.

28. WHAT DOES “SHATTERPROOF GLASS” MEAN IF THE GLASS THEN BREAKS?

This is a “current” term which is not completely accurate. It refers to glass that has undergone a particular process called “tempering”, which brings the object to a temperature of about 600°C and then cools it suddenly (with cold air distributed according to the thickness of the glass), causing controlled raised tensions inside the object. In practice, a layer of tensile stress is created, bounded by two layers of compressive stress, giving the object increased resistance. The molecular structure which is created allows the glass to shatter into very small particles in the event of a sharp impact, and these cannot cause damage.

29. WHY ISN’T SHATTERPROOF GLASS USED FOR FOOD CONTAINERS?

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This is perfectly possible because it is a secondary process, but shatterproof glass is not generally used for large scale production of containers because


1. SOME QUESTIONS ABOUT GLASS

it is unnecessary for the type of use made of the product and would be much more expensive because of the procedure described above.

30. HOW CAN GLASS BE COMPLETELY TRANSPARENT WHEN IT IS MADE OF MINERALS?

Because it loses its original physical structure and is subject to transformation as a result of the high melting temperatures (about 1500°C).

31. WHY ARE SOME GLASS CONTAINERS DARK IN COLOR?

The market requires different colors to protect different food products from light by using the filtering power of certain colors, and it is also for aesthetic reasons.

32. SHOULD A GLASS CONTAINER BE WASHED BEFORE FILLING IT FOR THE FIRST TIME?

When a glass container reaches the warehouse after production, it is clean because all the production phases guarantee this feature. Nevertheless, since the openings of the jars and bottles sometimes remain in contact with the packaging materials for quite a long time and condensation may form, the operator responsible for the final packing of the product before it is actually filled generally carries out an inspection using special equipment. The container is often turned upside down and blown with compressed air, or in other cases a precautionary wash is carried out with steam that is then powerfully aspirated in order not to leave any residue.

33. WHY ARE BOTTLES PRODUCED IN DIFFERENT COLORS?

This is due to aesthetic reasons and for the protection of the contents, since some colors filter light.

34. WHAT COLOR OFFERS THE BEST PROTECTION FROM UV RAYS?

Antique green 99%, oak 98%, amber 99% (see page 178).

35. WHY IS GLASS NOT ALWAYS COMPLETELY TRANSPARENT, BUT IS SOMETIMES “GREY”?

This is a problem directly linked to the glass batch which is often made up of

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1. SOME QUESTIONS ABOUT GLASS

“cheap” silica sands or high quantities of cullet. Since the physical and chemical features of the final product do not change, this kind of glass is used for containers of widely used, everyday products where low cost is a primary requirement.

36. WHY IS OIL GENERALLY PACKED IN DARK BOTTLES IN ITALY AND IN CLEAR GLASS BOTTLES IN OTHER COUNTRIES?

There is no particular rule about this. Perhaps Mediterranean culture requires a container that protects the product from light (because of the oxidation effect), especially in the case of high quality olive oil. Nevertheless many good quality products are also bottled with the so-called “mezzo bianco” or semi-clear glass (which is actually light green). This has a lower filtering power but allows better product visibility, and since the distribution system is very fast nowadays, the use of this glass does not create particular problems.

37. WHY IS DARK GLASS USED FOR RED WINE?

Aside from tradition, it is again a question of protecting the product from light, since the wine is sometimes “aged” in these bottles. In fact, white wines, which generally have a shorter life, are often sold in clear glass bottles.

38. WHAT IS THE DIFFERENCE BETWEEN A NATURAL CORK AND A SYNTHETIC CORK?

With the current technology, there are some fundamental differences between the two closure systems. A natural cork adapts better to the inside of the neck, allowing the appropriate, slow transmission of air, which is ideal for the natural aging of the wine. It also has no expiry date, unlike synthetic corks whose already low elasticity gradually disappears with time when not in use. When a synthetic cork is used, particular attention is required during the bottling process because it is necessary to adopt an air pre-vacuum system while introducing the cork (in order to prevent the cork rising again) and the jaws should be perfectly closed. Natural cork, on the other hand, is much more flexible and even private users can insert them using a very simple machine with no other tools necessary. Obviously, using synthetic corks for short periods avoids the problem of cork taint. Moreover synthetic corks do not release any particles into the liquid and they are therefore often used for spirits, in the form of the so-called “mushroom cork”.

39. WHAT IS A “POURER” USED FOR?

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A “pourer” is used to prevent random drips falling from the bottle when pouring out the liquid. Nowadays bottle tops are often already equipped with a pourer.


1. SOME QUESTIONS ABOUT GLASS

40. WHAT IS THE “PLASTIC GRID” USED FOR?

The plastic grid, usually made of food-safe plastic, is used in jars to keep products entirely submerged in their preservation liquid (oil or other liquids).

41. DOES GLASS USED FOR FOOD CONTAINERS HAVE A DIFFERENT COMPOSITION COMPARED TO GLASS USED FOR INDUSTRIAL PURPOSES (DOORS, WINDOWS, ETC.)?

Yes, but relatively slight differences to ensure the different malleability of the molten glass. In cullet used to produce jars and bottles it is quite common to find cullet deriving from sheets of glass with a slightly different composition: this is not generally welcome, but if small amounts are mixed with the normal batch of raw materials, the result is still acceptable.

42. CAN THE DECORATION OR APPLICATION OF A FROSTED FINISH ON A BOTTLE BE HARMFUL FOR THE CONTENTS?

These operations are only harmful if the interior of the bottle mouth is not kept adequately protected during the procedure.

43. IS IT POSSIBLE TO CREATE ANY KIND OF CONTAINER WITH GLASS?

Theoretically there are no size or shape limitations. It is generally the customer who decides, based on the production process (manual or industrial), or economic aspects, etc..

44. WHAT IS THE DIFFERENCE BETWEEN ORDINARY GLASS AND CRYSTAL?

Glass is a generic term that includes different types of the same material. Crystal is a particular type of glass principally made up of lead, barium and zinc which are all substances that increase the refraction index responsible for its shine. The batch used to produce crystal always requires slightly lower melting temperatures than glass for bottles. Moreover crystal is not as hard as traditional glass and therefore it can be more easily engraved.

45. MANY BOTTLES HAVE A VERY THICK GLASS BOTTOM. WHAT IS THIS FOR AND HOW IS IT MADE?

The extra thick glass on the bottom of bottles is primarily for aesthetic reasons to make the bottle look more valuable, and in the case of clear glass, to enhance the transparency and purity of the bottle.

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1. SOME QUESTIONS ABOUT GLASS

Technically, the concentration of glass on the bottom of the bottles is achieved by creating a special preparatory mold (parison) with a higher glass mass than that of a normal bottle, that does not get deformed during the first blowing process.

46. IS THERE A SPECIAL PROCESS FOR MAKING BEER BOTTLES?

Bottles that are especially designed for classic or craft beers (with fermentation in the bottle) are not manufactured using particular technical features except for the resistance to pressure, since - as for the champagne method they must resist up to 6 bar. They are generally made in amber or dark green glass for better protection from UV rays.

47. WHY ARE THERE DIFFERENT TOPS FOR BOTTLES? DO THEY AFFECT THE CONTENTS? ARE BOTTLE CAPS SUITABLE FOR ALL TYPES OF BOTTLED PRODUCTS?

The type of closure system used must be selected according to the contents of the bottle/jar, but the traditional mode of consumption is often the main factor influencing this decision. Closures themselves, whether made of cork or synthetic material, have no technical limitations in their use. Aluminum screw caps - very useful because they can be re-closed - are used mainly for carbonated drinks, spirits or oil. Closures for jars depend on the type of product contained and on the heat treatment used. Over time, the need for products that could last longer while retaining their principal features, thus extending their distribution, has encouraged the development of new sealing and packing systems. These depend on the product characteristics and on operational requirements in order to achieve the longest and best shelf life for the products. From the old methods of sealing with oil and natural corks, we have now arrived at a host of increasingly specialized and specific closure solutions to deal with all possible problems involving protecting the packed product from the external environment. These solutions also seek to offer the consumer ways to detect any chance or intentional interference with the original packaging (tamper-proof seals and flip caps, etc.).

48. WHY DO SOME BOTTLES ON THE MARKET USE NON-REFILLABLE CAPS?

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Non-refillable caps are required by law in accordance with art. 18 of Law 161/2014, which regulates the distribution chain for virgin olive oils to prevent false imitations. The same principle is applied to alcoholic drinks, for marketing purposes, although it is not currently required by law. In this case, the closure also serves to control the flow when pouring.


1. SOME QUESTIONS ABOUT GLASS

49. WHY DO SOME PRODUCTS ONLY REQUIRE PASTEURIZATION WHILE OTHER PRODUCTS NEED STERILIZATION? SOMETIMES WHEN WE BUY A GLASS JAR AT THE SUPERMARKET, THE LID IS LABELLED “SAFETY LID” TO PREVENT THE CUSTOMER FROM BUYING THE PRODUCT IF THE BUTTON IN THE CENTER OF THE LID IS RAISED. WHY?

The pasteurization process which destroys microflora must be immediately followed by rapid cooling of the product and it is suitable for very acid products (such as fruit juices, tomato sauce, beer, etc.). The sterilization process is necessary for food products with low acidity (e.g. fish, meat, vegetables etc.), which are more susceptible to bacterial infection which may create pathogens. The increase in temperature from 95°C for pasteurization to 125°C for sterilization, enables the bacteria to be destroyed and, with the creation of a vacuum inside the container, the contents to be preserved. When the button at the center of the lid is depressed, it shows that the container is properly sealed and the vacuum inside the container has been maintained. When the button is raised, this shows that the vacuum in the container has been lost and the safe preservation of the contents can no longer be guaranteed.

50. THERE ARE SOME BLACK OR VERY DARK GLASS BOTTLES ON THE MARKET. IS THAT A DIFFERENT KIND OF GLASS? WHY IS IT SO DARK?

We generally call it black glass: its composition is exactly the same as the glass in other containers but with a higher concentration of iron oxides, chrome and manganese that practically block the passage of light. This material is frequently used for cream-based alcoholic drinks (mainly cream with milk and eggs).

51. ARE THERE ANY SIZE LIMITATIONS FOR GLASS CONTAINERS IN COUNTRIES INSIDE OR OUTSIDE THE EU?

First of all we have to divide the containers into two categories: measured containers (mainly bottles) and non measured containers (pots/jars). The first category shows the capacity of the container on the bottom and the symbol 3 (reversed epsilon). The capacity is pre-determined, depending on the type of liquid contained. For instance, in EU countries, alcoholic drinks can be in bottles of 700 ml or 1500 ml, while in the USA, bottles can be 750 or 1750 ml. Other capacities are used in both geographic areas (250 ml, 375 ml, 500 ml, 1000 ml). Non measured containers are generally pots or jars where the volume of the container does not correspond to the volume of the content. These containers are produced to give the user the ideal volume for packaging a certain quantity of the product. In this case, the label provides the necessary information, stating the product weight, the amount

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of preserving liquid and the symbol “e”, which means that the filler is responsible for providing the content details. There are no general rules that apply to these containers because they differ according to market sector, national units of measurement, normal market practice etc..

52. TYPES OF GLASS: ARE TUMBLERS, HOUSEHOLD OBJECTS, WINDOWS, LENSES, OPTICAL MATERIALS ETC. ALL MADE UP OF THE SAME GLASS AS THAT USED FOR POTS, JARS AND BOTTLES?

There are different types of glass which are all manufactured by the same process of melting raw materials, based on silicon, soda and potassium, in a furnace. These various types of glass meet different requirements. For instance: • Tableware, consisting of the traditional glass tumblers and containers. The batch used contains a higher percentage of BaO (barium oxide) - to give more shine and transparency - and a sand with a low percentage of iron oxides. We refer to this glass as “long glass”, meaning that it has a lower melting point. • Pirex: this type of glass must have a low expansion coefficient so that the container can resist sudden changes of temperature. The chemical composition of the batch is therefore different: it contains boron and is called “borosilicate glass”. The same type of glass is used in the amber-colored glass - with higher resistance to light - for laboratory or pharmaceutical containers. • Crystal: this is obtained by adding lead oxide (up to 35%), which gives it its shiny finish and the typical crystal sound. • Plate glass: apart from the different chemical composition of this type of glass, to give greater resistance, a whole chapter could be devoted to the production methods. 90% of the plate glass produced worldwide is manufactured using the “float glass process”: the molten batch is poured into a long molten tin bath in controlled atmosphere. The glass floats on the tin and spreads along the bath surface thus creating smooth surfaces on both sides. The glass cools down and becomes solid as it flows along the bath, creating a floating ribbon. Then the product is flame polished so that the surfaces are perfectly parallel. This kind of glass is considered to be unsuitable for building purposes because it tends to break into large, sharp pieces. In order to remedy this problem, when plate glass is subject to impact or static stress the individual plates have to be tempered by being heated in a furnace up to 600°C and then suddenly cooled down by forced drafts of cold air. Two or more glass plates are coupled in order to increase thermal insulation (for

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1. SOME QUESTIONS ABOUT GLASS

windows or glass walls) and they are kept separated by air or gas (argon, krypton or xeno) or they are kept together by using plastic film according to their final use.

53. THERE ARE COLORED BOTTLES (WITH BOTH TRANSPARENT OR OPAQUE FINISHES) ON THE MARKET. ASSUMING THAT THESE ARE SUPPLEMENTARY PROCESSES, CAN WE BE SURE THAT THIS DECORATION WILL NOT “DETACH” FROM THE BOTTLE? HOW CAN WE BE 100% SURE?

This is a very extensive subject. Please refer to page 84.

54. WHY IS THERE SOMETIMES A NUMERIC CODE PRINTED ON GLASS CONTAINERS?

EC Law 178/2002 specifies traceability requirements for food products and the need to be able to retrace every single step of the food supply chain. EC regulation 2023/2006 governs GMP (Good Manufacturing Process) rules. This is why many glass factories - in order to comply with the above rules - print numeric codes on their bottles which indicate the production day, time or other production details even once the container has been filled and separated from the production identification code attached to the pallet. Generally this printing is carried out with special inks which are visible only under UV light or by using laser technology.

The use of traditional indelible ink is very rare. Filler companies - which are directly obliged to make their products totally traceable - print their reference codes on the glass or the lid using inks which are visible to the naked eye.

55. SOMETIMES IN WINE SHOPS THERE ARE VERY BIG CHAMPAGNE BOTTLES. ARE THEY AS FUNCTIONAL AS THE ORDINARY BOTTLES WHICH ARE GENERALLY USED AT HOME, OR DO THEY ONLY HAVE AN AESTHETIC PURPOSE?

They are certainly as functional as the ordinary bottles. They are subject to very strict quality controls because of their size and their sparkling content. They are generally used in sizes from Magnums to Methuselahs, and more rarely Salmanazars and Nebuchadnezzars and their resistance is tested up to 16 bar. The last four are used very rarely because of dangers related to champagne pressure in such high quantities. They have been used for sparkling wines, as in the case of the 27 liter “primat” (which corresponds to 36 ordinary bottles) to celebrate Moser’s Hour record in Mexico City.

25


1. DOMANDE E CURIOSITÀ SUI CONTENITORI IN VETRO

bottles bottles bottles bottles bottles bottles

Bottle

Biblical name, founder King of the Kingdom of Israel in the 9th century B.C.

Biblical name, the first King of Judea

Biblical name, the oldest man in the Old Testament

Biblical name, King of Assyria

Biblical name, name of one of the Three Wise Men

bottles

bottles

bottles bottles

Biblical name, King of Babylon

Biblical name, King of Israel, son of King David

Biblical name, the giant killed by the stone from David’s sling; also called PRIMAT on the occasion of Moser’s Hour record in Mexico City in January 1984

Biblical Name, King of Salem

These bottles have a guaranteed pressure tightness of 6 bar up to the Jeroboam. In larger capacities this guarantee decreases to 1.5 bar.


1. SOME QUESTIONS ABOUT GLASS

TECHNIQUES EXPLAINED FOR THE MOST CURIOUS READERS

56. WHAT CAUSES THE “WAVES” THAT ARE VISIBLE AROUND THE LOWER CIRCUMFERENCE OF A CLEAR GLASS BOTTLE? WHY DO THESE WAVES SEEM TO DISAPPEAR WHEN THE BOTTLE IS FILLED WITH LIQUID?

These waves are left by the “parison” (see pages 53 and 78) caused by the different temperature of the blank mold at the points where the glass ends after the gob is loaded. Careful adjustment of the production equipment certainly helps to prevent this optical effect (that is even more visible on clear glass bottles). Today progressive pressure valves are used to limit this inconvenience. Once the bottle is filled, 90% of the optical effect disappears and the mechanical strength of the bottle is not affected. Other shadows on the body of the bottle may be caused by the incorrect loading of the glass gob.

57. HOW LONG DOES IT TAKE TO MANUFACTURE A BOTTLE AND AT WHAT TEMPERATURE IS THE GLASS PROCESSED?

It takes 10 to 15 seconds to transform the glass gob into a bottle that is immediately sent to the annealing lehr in order to eliminate the surface tensions in a process that lasts 1 to 2 hours. Information on the temperatures is provided on page 46.

58. WHY DO SOME BOTTLES HAVE A VERY SHINY FINISH WHILE OTHERS APPEAR ROUGHER AND MORE OPAQUE?

This is basically a question of the quality of molds and specifically: • the material used for creating the molds (see pages 78-83) • the maintenance of the molds • the method used to lubricate the molds during production.

27


1. SOME QUESTIONS ABOUT GLASS

59. WHY DO SOME BOTTLES HAVE THE SAME CAPACITY BUT DIFFERENT GLASS WEIGHTS?

This is due to different manufacturing requirements, for example the shape of a bottle may require a higher quantity of glass (e.g. for edges) or the use of the bottle may require a higher mechanical strength (for carbonated drinks or champagne), or to marketing purposes, because a heavier bottle appears to be more valuable or because the thickness of the glass can result in different shades of color.

60. WHAT MATERIAL IS USED FOR MOLDS AND HOW LONG DO THEY LAST?

Molds are made of special cast iron and they can be used for a long time depending on the quality of the material, the maintenance and the number of times they are placed in the machine for production. Just to give an idea, if a set of molds is used only once, it could manufacture a million pieces but if the production is divided into several batches of 100,000 pieces, then these molds would last no longer than 6 or 7 times because the start up of production and the maintenance operations tend to wear them out.

61. WHY DO I HAVE TO WAIT FOR SOME WEEKS FOR MY BOTTLES BEFORE THE “GLASS WEIGHT” IS ON THE MACHINE?

The glass is sent from the furnace to the molding machines through pipes made of electrofused material (feeders). For the glass to be properly conditioned in these pipes, it is important to avoid significant differences in the quantity of glass material that is extracted, which should be similar to the quantities of glass extracted by the other pipes connected to the furnace. For example, it is better to go from producing an article weighing 350 gr to one weighing 500 gr and so on, rather than making a leap from 350 gr to 900 gr without a gradual progression.

62. ARE BOTTLES MADE BY WELDING TWO HALVES TOGETHER?

28

No, absolutely not. The vertical lines that are visible to a greater or lesser extent on bottles and jars correspond to the joining points of the two half-molds. See pages 78 and 83.


1. SOME QUESTIONS ABOUT GLASS

63. WHY CAN A GLASS FURNACE NEVER BE TURNED OFF?

This is a technical feature of continuous production that is common to blast furnaces as well. The melting temperature of 1500°C takes around 12 days to reach, with very high energy consumption. Obviously the furnace cannot be turned on and off at will. Moreover, the glass material in its cooling phase could cause damage to the delicate parts of the furnace such as the “throat”, and the refractory material that the furnace is made of goes through some highly critical points during certain changes in the temperature range (approximately between 1200°C and 1100°C and between 900°C and 800°C).

64. HOW IS THE COLOR CHANGED?

The color can be changed through a progressive but rapid change in the glass batch or by adding colorants. Obviously it takes a few days to clean the whole furnace from the previous color, since the molten glass mass amounts to about 100-300 tons depending on the furnace surface. Moreover glass has a slight elliptical movement and this causes the formation of pockets of resistance in corners of the furnace to the glass whose color is to be changed, which is also due to slight temperature variations in those positions and therefore different levels of viscosity. It is also possible to color glass directly in the feeders, but in this case the feeders need to be specially designed so that they are the correct length to condition and homogenize the glass properly after the introduction of the “frit” (flakes of colorant material). In this way, it is possible to use clear glass on some machines and colored glass on other machines without having to change the contents of the whole furnace. In any case, this is a complicated and quite expensive procedure and only permits a limited range of colors.

65. HOW IS THE MOLD CHANGED?

This is one of the most complex operations in a glass factory and it must be carried out by one or more teams of qualified technicians. When the required quantity of an article has been reached, production is stopped by deviating the glass gobs from the feeders into special cooling water tanks instead of into the molds. Some technicians start by working on the feeder mechanisms to set the new glass weight, if necessary replacing the cuvettes through which the glass gob passes and setting the new parameters for the entire feeder pipe. Others work on the machine sections, replacing the molds and preparing the new production process, including the transfer of the new articles to the annealing lehr. These two phases are carried out at very high, uncomfortable temperatures, with the additional psychological pressure of the “time factor”, since factories work on a continuous production cycle.

29


1. SOME QUESTIONS ABOUT GLASS

The change of molds can take 2 to 6 hours, or even 1 full working day, depending on the production, to finish setting it up. While these operations are being carried out in the so-called “hot” area, another team is setting up the new parameters on electronically controlled machines in the “cold” area, where products are selected and packed, using - where possible - a range of defective samples of the new article which have been kept from previous productions.

66. WHAT IS THE DIFFERENCE BETWEEN A SINGLE GOB AND A DOUBLE GOB?

A double gob is when two gobs are collected at the same time from a feeder using a cuvette with a double orifice. In some cases it is possible to collect 3 or 4 gobs at the same time, that all go into the same forming section of the machine (obviously into different molds). The machine can have 6, 8, 10 or even more sections. With the use of more glass gobs, it is possible to produce more articles in the same production time unit.

67. WHAT IS “SAMPLING INSPECTION”?

A production batch can be satisfactorily evaluated using a statistical control method (internationally regulated by a specific reference standard), which consists in the random sampling of a certain number of pieces in proportion to the overall quantity of the production batch. The results of this sampling inspection should be representative of the quality of the whole batch. See page 184 onwards.

68. WHO DECIDES THE WEIGHT OF A BOTTLE AND ON WHAT BASIS?

There are a number of factors that influence the weight of a bottle: the bottle volume; the minimum thickness required for the sides and neck of the bottle to make it possible to use; the need to provide specific axis loads or to ensure a certain resistance to internal pressure (e.g. for champagne bottles); and finally aesthetic requirements.

69. WHAT IS THE MOST SUITABLE WAY TO FIT THE CAPS AND LIDS? MANUALLY OR AUTOMATICALLY?

30

Both methods are suitable provided that the entire packaging process is correct. Obviously the automatic method ensures a more consistent and uniform application of the closure to the glass container.


1. SOME QUESTIONS ABOUT GLASS

70. HOW ARE SCREW CAPS MANUFACTURED AND WHY ARE THEY CATEGORISED AS PASTEURISABLE OR STERILISABLE LIDS?

Screw caps are manufactured from tinplate sheets: they are cut into disks which are then deformed at their edges using special chucks which form the traditional “skirt” and the threads that allow the cap to fasten onto the glass jar. In order to ensure a perfect coupling between the jar and the lid, some “soft materials” called mastics are used, which need to be resistant to heat treatments to enable the preservation of the contents of the jar. More specifically, pasteurization, at a temperature below 90°C; sterilization between 120/125°C.

71. WHY ARE GLASS JARS GENERALLY VACUUM-SEALED? HOW IS THE VACUUM CREATED DURING THE PRODUCTION PROCESS?

Jars are vacuum-sealed in order to extend the preservation period for the contents (shelf life). There are three different methods of vacuum-sealing: • mechanical

or dry vacuum-sealing: using bell jars connected to pumps which remove the air (mainly for dry products). See picture on page 187; • steam vacuum-sealing: this is the most commonly used system. A steam jet is injected into the container before sealing it; • venting vacuum-sealing: once the jar has been filled with the product, it is closed in a tunnel or autoclave; a controlled increase in temperature allows the release of the air contained between the product and the lid.

There is another method which is currently used in households to pack products (e.g. fruit jam) which consists in filling the pot with the very hot product almost up to the brim with no empty space left at the top. When the pot is closed, the product cools down and automatically creates a vacuum seal.

72. WHY SHOULDN’T LIDS BE RE-USED?

Because the mastic used for the lid, the material which allows the “air-tight” seal, doesn’t have the same elasticity after the first use. The “threads/lugs” that ensure the coupling of the lid to the jar finish become deformed after the first use.

73. HOW IS THE SIZE OF A CORK FOR A WINE BOTTLE DETERMINED?

The size of a cork (width) is always calculated taking into account the type of wine (still or sparkling) and the internal caliber of the container at a depth of around 40-50 mm (about 18.5 mm on average). For still wines

31


1. SOME QUESTIONS ABOUT GLASS

this diameter +6 mm is used for natural corks or +4 mm for technical cork stoppers such as the double-disc cork. Sparkling wines always have double-disc corks, so 4 mm are added.

For spumantes (Italian sparkling wine) a single kind of cork is used that is ø 30.5 mm (the cork starts off larger in order to maintain the pressure). The cork height is 40 mm due to problems in remaining air-tight and because it is the minimum size possible for the cutting and processing of cork. This can vary from 40 to 54 mm for various reasons but mainly for marketing reasons. A cork of 48 mm in height is always used for spumante.

74. HOW IS THE SIZE OF A SYNTHETIC CORK DETERMINED?

The answer is simple for synthetic corks since there are only two standard sizes for diameter and two for length, that is to say ø 22 x h 38 or h 42 for still wines and ø 23 x h 38 or h 42 for sparkling wines. Unfortunately, at present few manufacturers have distributed a synthetic cork suitable for containing pressure from gases.

75. HOW IS THE HEIGHT OF A SCREW CAP DETERMINED?

These parameters are fixed by international standards which establish diameter and height along with other data, e.g. ø 28 top and bottom.

76. ARE METAL AND PLASTIC SCREW CAPS ALWAYS INTERCHANGEABLE?

Some kinds of caps have the same gauge for the screw thread and therefore they are interchangeable as long as there are no specific requirements deriving from the contents or the filling procedures.

77. WHAT IS THE DIFFERENCE BETWEEN AN ORDINARY GLASS BOTTLE AND A BOTTLE USED FOR “SPARKLING WINE”?

32

There are some technical differences: in sparkling wine bottles the shape of the bottle is different (e.g. bottles with sharp edges are not suitable), the weight of the glass needs to be of sufficient thickness to withstand the internal pressure, and there is a picure (punt) or a heavier, stronger base. Moreover they also need to have a uniform distribution of the glass.


1. SOME QUESTIONS ABOUT GLASS

78. WHAT ARE THE SMALL BUMPS ON THE BOTTOM OF THE BOTTLE FOR?

They represent the coding for the mold and they allow electronic control of the production process and of that particular mold.

79. WHAT IS THE REASON FOR THE STIPPLING ON THE BOTTLE BASE?

The stippling helps to keep the bottle stable on the conveyor belt during production and to keep the bottle punt (which is still at 650°C) separate from the metal belt, preventing cuts to the bottle base through contact with different temperatures.

80. WHAT ARE THE ENGRAVINGS (LETTERS AND NUMBERS) ON THE BOTTLES FOR?

They represent a sort of identity document for the bottle: they contain the name of the producer with its factory trademark, the brim capacity and the filling level, the number of mold cavities used to produce the bottle, and the symbol which indicates that the bottle/jar is suitable for food products.

1. nominal capacity in cl or ml 2. symbol for measuring container bottle* 3. filling level 4. bottom with dots 5. symbol indicating it is suitable for food 6. manufacturer’s trademark 7. reference number of mold 8. bottom with crescents

* The reversed epsilon similar to a number “3” is the symbol established by EC

regulations to identify measuring container bottles. This refers to containers which have the necessary metrological features guaranteed by the glass manufacturer, which make it possible to measure the actual contents with the appropriate accuracy when filled to a certain level from the brim (EC directive 106/75).

33


1. SOME QUESTIONS ABOUT GLASS

81. WHAT IS GLASS TYPE III? ARE THERE OTHER TYPES OF GLASS?

This is a classification of glass for containers which has been adopted by different Pharmacopoeias in order to establish a more appropriate use of glass in containers according to their contents. There is glass type I, type II and type III. Type I is a borosilicate glass (known as Neutral) with a high hydrolytic stability suitable for containing injectable products. Type II derives from type III: thanks to a special ammonium sulfate treatment of the internal surface, this type achieves a similar hydrolytic stability to type I and is suitable for containing acid or neutral products (e.g. infusion solutions). Type III is a soda-lime glass with a low alkali content and good hydrolytic stability, suitable for containing preparations that are not in aqueous or alkaline sensitive solutions. There is another type of glass which is suitable for containing food products and known as Type A Glass (soda-lime glass) which does not require any specific hydrolytic resistance, unlike type III.

82. WHY DO LABELS ON BOTTLES COME OFF QUITE EASILY OR HAVE WRINKLES?

The reason can range from incorrect application methods to a lack of compatibility between the label glue and the surface treatment of the container, to the glass shape that may have only one radius of curvature in the label application area. It often depends also on the label material, whether it is paper, PVC or something else, and on the ability of the material to adapt its shape on application to glass. All treatment processes can be carried out well or badly and labels also come into this category of quality control issues, which include the features of the glass, the selection of the most appropriate material, the quality of the labeling system, the overall quality of the production process, the ability of the worker to adjust all the components so that the work may be carried out appropriately.

83. WHAT IS THE SIGNIFICANCE OF THE “MINIMUM THROUGH BORE� AND THE INTERNAL PROFILE OF THE NECK?

34

These elements are of crucial importance because the glass container is filled using a steel tube. Failure to take account of the minimum through bore (internal diameter of the opening) can lead to breakage of the container or tube, damage to the filling process, failure to complete the filling phase, etc. The internal profile of the neck refers to the stoppering profile inside the neck down to below the finish, while the minimum through hole applies to the whole length of the bottle neck.


1. SOME QUESTIONS ABOUT GLASS

84. WHICH PARTS OF THE MOLDS ARE INTERCHANGEABLE AND WHAT CHANGES CAN BE MADE WITHOUT HAVING TO REMAKE THE ENTIRE SERIES OF MOLDS? • the

collar, provided that it fits the diameter of the neck; bottom, with or without a punt or to allow different capacities; • the finishing mold allowing a neutral or customized version of the same bottle. • the

85. WHEN A GLASS BOTTLE OR JAR BREAKS, YOU CAN SOMETIMES SEE THAT THE GLASS THICKNESS IS NOT UNIFORM. WHY IS THIS?

The glass container is formed in the finishing mold by a blow-blow process. The stretching of the glass is therefore influenced by the temperature of the glass batch. The reduction in glass thickness is often more evident in bottles and usually appears at 2/3 of the bottle height, going down towards the bottom, which corresponds to the height of the parison. So a certain amount of difference in the thickness is a natural physical feature provided it does not affect the solidity of the container.

86. WHAT IS THE “HEAD SPACE” IN A BOTTLE OR JAR? WHY CAN’T THEY BE FILLED UP TO THE BRIM?

Independently from the filling method, head space is necessary to allow the expansion of the liquid contained, caused by variations in temperature. The percentage of head space compared to the volume of the container must be calculated according to the filling method and also according to the type of content. For example, alcoholic drinks require a head space of about 4-5% of the volume to allow for expansion of the product, while maple syrup - which is generally packed hot - requires a head space of 7% to ensure the nominal quantity after cooling. The filling level for bottles is indicated on the bottom and it is expressed in the distance from the brim (in millimeters). The nominal capacity for jars indicates the milliliters of water that can be contained by filling them to the brim while the product content is generally expressed in grams. Jars that contain several different products (each product has different volume variations) require careful attention to the head space during the packaging process and the heat treatment which follows the filling and sealing operations.

35


1. DOMANDE E CURIOSITÀ SUI CONTENITORI IN VETRO


1. DOMANDE E CURIOSITĂ€ SUI CONTENITORI IN VETRO

Final part of the production cycle. The containers are checked with optical and electromechanical machines and are then sent to the accumulation table, ready for the final packaging operations.


Parison of the Contessa Decanter before being sealed in the finishing mold.


2

LOOKING INTO GLASS

1. THE HISTORY

page 40

2. DEVELOPMENT OF THE GLASSWARE INDUSTRY

page 42

3. THE GLASS CONTAINER AND THE DEVELOPMENT OF ALTERNATIVE MATERIALS

page 44

4. GENERAL NOTES

page 45

5. TECHNICAL INFORMATION

page 46

6. THE TECHNOLOGICAL CYCLE FOR THE MECHANICAL PRODUCTION OF HOLLOW GLASS

page 48

7. DIAGRAMS OF PRODUCTION PLANTS

page 70

8. ABOUT MOLDS

page 78

9. NOTES ON THE PROCESS OF GLASS DECORATION

page 84

10. SILK-SCREEN PRINTING

page 84

11. SANDBLASTING

page 88

12. ACID FROSTING PROCESS

page 89

13. PAINTING

page 93

GLA SS


2. LOOKING INTO GLASS

THE HISTORY

Although glass production remains shrouded in mystery, archaeological remains show that it dates back to the most ancient periods of human history. The discovery of glass (perhaps obtained by heating blocks of sodium carbonate or natron on sand) is generally attributed to Phoenician merchants who were shipwrecked near the outlet of a river in Asia Minor. This theory is rather far-fetched, since the temperatures needed to produce glass were difficult to reach in that period and in such conditions, but it may offer some scientific truths regarding the use of silica sand (the raw material), soda (the melting agent) and calcium carbonate (as a stabilizing element) present in the ashes of seaweed and other coastal plants. On the basis of archaeological remains and fragmentary information from ancient writers, the most ancient places of glass production are believed to be Phoenicia and Egypt. At that time, this activity was closely linked to the production of jewels, amulets, decorative objects and, to a much lesser extent, containers for oils and fragrances. With wars and the frequent travelling of merchants in the Mediterranean area, the art of glassmaking began to flourish in Persia, Cyprus and Syria, where it is believed that the process of glass blowing, including with the use of terracotta molds, started in around 200 B.C., with the production of vases used as oil bottles and trophies for sports competitions. During the 9th century, under the influence of the Islamic culture, glass became an even more valuable material, with the intensity of the colors, the skilful engravings and the technique of enamel painting to create decorative objects. After the fall of the Eastern Roman Empire, many glass makers moved to Venice and later, (in around 1289) to Murano, where glass production reached incomparable levels of quality. From the 15th to the 18th centuries, new technological discoveries, along with changes in governments and trading agreements, led to the rise of glass production schools and industries all over Europe, stimulating the search for different production methods and techniques; the traditional production of decorative objects such as fine glasses and (a few) containers was accompanied by the production of sheet glass, an industry which experienced varying fortunes to begin with. An important step in the development of glass production came with the introduction (in 1828) of melting furnaces heated with steam instead of wood, and later, in the 1860s, the use of gas furnaces with regeneration and heat recovery systems. It was in that period that the Germans Schott and Abbe founded in Jena the first

40


2. LOOKING INTO GLASS

“Figline (Valdarno), glass factory�, Alinari Collection.

plant to use technological and scientific methods, representing the first step in the introduction of mechanical glass manufacturing: this completely changed the importance of glass in society, leaving the highly specialized production of decorative and luxury objects to the ancient schools of Murano, Lambert St. Cloud, St. Louis, Baccarat, etc. The spread of new ideas during the 18th and 19th centuries changed both the social structure and human needs: glass manufacturing became a new type of activity divided into different fields, with only their origin as a common denominator. The evolution of transportation created opportunities for competition, thus stimulating the search for new shapes and innovative production processes. Accompanying the major changes in living conditions which took place in the last century came a whole series of transformations and developments, and glass, which had remained unchanged for centuries, also became a part of modern life. Porcelain vases, earthenware cups and tin flasks which, until then, had unquestionably reigned as household items, were rapidly replaced by glass containers and tableware.

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2. LOOKING INTO GLASS

DEVELOPMENT OF THE GLASSWARE INDUSTRY

In the “Italian Exhibition” of 1891, the glassware industry already had a sector to itself, which included sheet glass and household articles, furnishings and tableware made of glass, together with optical glass and jars, bottles, flasks and demijohns. At that time Italy was fully keeping up with production in the rest of Europe (although some commercial disparities already existed) and some important companies became established that are still active and well-known today (such as Bormioli, S.A.V., etc.). The real turning point in the production of glass containers and household tableware came with the improvement of the methods used for melting raw materials (wood was replaced by coal and then by natural gas), which allowed the production of a stronger glass with good surface resistance that was able to keep its color and did not alter on contact with its contents. This meant that glass could be marketed as an “incorruptible” material. At first, the glass blowing technique consisted in taking a small quantity of molten batch with a special “blowing pipe” and introducing it into a mold (made of wood, iron or pig iron). Then the glass maker blew and shaped the material until it reached the desired size and shape. When the glass was solid, the container was detached from the pipe using a little water; the glass maker immediately applied a small quantity of molten glass around the raw finish, which was then cut with shears to obtain the desired shape. The container was thus ready to be annealed. This method was long, quite skilled and dependent on the abilities of the glass maker. It was improved in 1870 thanks to the innovative techniques introduced by the American, Weber, and by Arnall and Ashley from Britain, who began to use compressed air in the glass-blowing technique and a special double-mold system (made up of a blank mold and a blow mold). The difficult task of “gathering” remained a weak point in the production process, until a solution was found thanks to an invention by the American, Owens, whereby a certain quantity of glass was “tapped” in regular gobs in particular areas of the furnace and then introduced into a single-mold press. Later on, the glass was no longer taken from the melting furnace but from an innovative forehearth that was situated over a series of multi-mold rotating machines. Thanks to these techniques a continuous production cycle could be achieved. While the foreign competition forged ahead, much still remained to be done in Italy. In 1913, 68,000 tons of machine-made glass bottles were imported, increasing to 102,000 in 1922. This was because the most important Italian

42


2. LOOKING INTO GLASS

producers of drinks had already introduced automatic packaging lines and, in order to decrease their costs, they were forced to reject hand-blown bottles because of their irregularities and variations in capacity, since governmental regulations for the protection of consumers had already come into force. The nationalistic objectives set by the Fascist government stimulated improvements in production and Italian companies soon transformed their manufacturing techniques, which greatly reduced the need for imported goods. This was particularly true for the green glass used in bottles and flasks, while jars and pharmaceutical bottles were still hand blown in 1910 and automatic machinery was very limited. In 1925, the Bordoni (Milan) and San Paolo (Rome) glass factories were the first to introduce modern automatic production plants for blown and pressed glass. From the Thirties on, technological development continued without interruption, satisfying the growing internal demand for bottles, jars, milk bottles, etc.. Many glass factories were already in operation in Italy (for example V.R. Bordoni, Bormioli Rocco, specialized in the production of small bottles, S.A.V. in Altare, Vetreria Spadaccio, Vetreria F.lli Lodi for seltz bottles and laboratory glass, and Vetreria Etrusca that merged with other companies to become part of the Fiaschi company). From then until the present day, the constant succession of improvements and discoveries of new applications has resulted in an almost completely automatic production process, where electronics and precision machines are widely used at every stage of the production process. The glass maker of old has almost disappeared and has been replaced by a group of skilled technicians who establish beforehand, on the basis of careful research, all the necessary conditions for manufacturing the desired article, within the limits imposed by mass-production.

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2. LOOKING INTO GLASS

THE GLASS CONTAINER AND THE DEVELOPMENT OF ALTERNATIVE MATERIALS

After many years of continuous progress and development, the creation of new packaging (in the Sixties) with the technological availability of alternative materials such as plastics, tetrapack, aluminium etc., soon became powerful weapons in the hands of marketing specialists, whose main objective is to create new consumption needs and new tastes, and to introduce or impose new choices on the consumers, stressing the need for other, by no means minor features such as simplicity of use, comfort and novelty etc., which become key elements of the finished product. The frequent Trade Union conflicts at the time had a strong impact on companies using a continuous production cycle, which by definition, is inflexible. This increased the competitiveness of the so-called “alternative materials�. When the energy crisis broke out, the glass industry was further penalized at first (with increases in energy costs, soda and transportation) and many companies were forced to carry out major restructuring processes lasting several years. However, later the energy crisis impeded the spread of competing materials, which often derived from hydrocarbons or required high levels of energy consumption. But the main consequence of the energy crisis was the growing concern about environmental and ecological issues that forced both citizens and companies to think carefully about their activities and also highlighted the recycling potential of glass as well as its qualities as a non-toxic material. The recovery of the glass container industry at the end of 1978 has continued uninterrupted up to the present day (although it encountered some difficulties from 1981 to 1983), if it is considered in comparison with other alternative materials rather than in absolute terms of production quantities, and this is the result of definite choices rather than of the emotional factor. Many materials available today are the result of very careful scientific research aimed at enhancing their best qualities, saving energy and minimising their impact on the environment. This has presented new opportunites for marketing strategies, since the appropriate packaging can be selected for every product not just on the basis of the criteria of fashion or novelty, but with greater concern for the community and the environment. There is no doubt of the safety of a plastic container for liquid soaps for users, or of the extra hygiene and convenience of a blister pack for pharmaceutical pills, but it is equally true that no other container designed to contain food or

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chemical-pharmaceutical products has the same combination of beneficial qualities as glass, that is, it is: • water-proof • physically

and chemically neutral

• safe • completely

recyclable

So the continuing development of the glass container (including its different use in different sectors) is to be expected and hoped for in the coming years.

GENERAL NOTES The technical information provided in the following pages is merely “indicative”, i.e. it is intended to give the reader an idea of the production process, raw materials, temperatures, and dimensional aspects of a modern glass factory. The steady technical and economic developments in glass production and its adaptation to the requirements of the market may soon render this information obsolete and, therefore, it is to be considered merely descriptive.

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TECHNICAL INFORMATION

CHEMICAL CHARACTERISTICS Glass is obtained by melting a mixture of raw materials. The three main components in the process are: • silica,

which is the vitrifying element (it melts at very high temperatures); (sodium carbonate), which is the melting agent (it lowers the melting temperature of the silica); • calcium (calcium carbonate), which is the stabilizing element (it improves the chemical resistance of the glass). • soda

Other ingredients are added to these three components in order to obtain certain properties: • magnesium,

that lowers the speed and temperature of the devitrification and thus enables the working of the material at better temperature conditions; • aluminium oxide, which lowers the coefficient of thermal expansion, increases the viscosity levels at processing temperatures and improves resistance to water and thermal shocks. Other additives (nitrates, sulphates) are introduced in order to eliminate gas bubbles and improve the homogeneity of the vitreous paste, as well as coloring or decoloring agents. It is worth underlining that the decoloring of glass is not generally a chemical reaction but the result of a physical process based on the superimposing of complementary colors. With the production of flint glass (clear glass), despite the use of carefully selected raw materials, some impurities continue to be present (such as iron oxide or very small particles of chrome that give a yellow-green color to the batch). For this reason, appropriate amounts of other ingredients are added, such as selenium (pink) and/or cobalt (blue) to obtain the typical “colorless-transparent” aspect of glass. Other frequently added coloring agents are chrome (green), pyrite and graphite (dark yellow), copper (red).

TEMPERATURES (APPROXIMATE AVERAGE DATA) MELTING AT 1500°C

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REFINING AT 1300°C

FORMING AT 900/1000°C

ANNEALING AT 350/550°C


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PHYSICAL CHARACTERISTICS Because of its distinctive features, glass can be considered both as a solid (because of its hardness, the ability to maintain its shape, etc.) and as a liquid (because of its isotropy, disordered structure, etc.), and it is therefore sometimes described as a “high viscosity liquid”. Between its extreme fluidity during the refining phase and the solid state of the finished product, there is the so-called “working range”. • hardness:

this is increased by calcium and boron. Only diamond can scratch glass; • density: this varies according to the type of glass. On average it is 2.5 kg/dm3; • fragility: this well-known characteristic is partly a result of its viscosity, which may cause internal stresses during the cooling phase; these can be partially eliminated using a particularly careful annealing process (see page 43); • tensile and elongation strength: negligible; • resistance to compression: 40 kg/mm2. This makes it possible to use glass in the construction industry; • thermal conductivity: 50 times lower than steel and 500 times lower than copper. Glass is not a good heat conductor and this is another cause of its fragility; • conductivity of electricity: glass is a very bad conductor of electricity in its solid state (the glass used as an electrical insulator is obtained by using specific variations in its composition, since the presence of alkali must be minimised in order to eliminate the surface conductivity, created by the saline solutions that form between the dampness of the external layer and the sodium silicates - the white effect).

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THE TECHNOLOGICAL CYCLE FOR THE MECHANICAL PRODUCTION OF HOLLOW GLASS

PHASE ONE: PREPARATION OF A VITRIFIABLE BATCH The vitrifiable batch is prepared in a completely automatic plant, in which the different ingredients are weighed and sent to a mixer machine by means of completely closed conveyor belts in order to avoid any dust spillage. The mixing operation lasts for a few minutes. After the mixing operation, cullet is added to the mixture in proportions ranging from 20-80% in order to improve the melting process (cullet lowers the melting point of the vitrifiable batch, which results in energy saving); 1 kg of cullet produces the same quantity of glass. When different types of cullet are used, problems may arise as to color and uniformity. The batch obtained is then sent to the furnace on special conveyor belts.

Equipment for loading raw materials into the furnace.

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The actual heating in the furnace.


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INTERIOR OF A MELTING FURNACE. One of the two towers with its burners in operation. Every 20/25 minutes the operating towers are reversed. On the left of the photo, the heating of the raw material as it floats on the molten glass at a temperature of around 1500째C. The dark patches on the surface are raw material that has not yet melted.

PHASE TWO: MELTING THE BATCH The batch is melted in a furnace equipped with a heat recovery system with air regeneration chambers made of refractory materials or through a metallic heat exchanger to pre-heat the air for combustion. The furnace has two continuously working tanks with a maximum production capacity of around 3 tons/day per square meter of surface. The molten mass is contained in the main tank (melting chamber) that is followed by a smaller conditioning tank (working chamber). The two chambers are separated and the glass flows from the melting chamber to the working chamber through a special throat. The combustion occurs in the space between the surface of the molten glass bath and the furnace crown. The surface of the melting chamber generally varies from between 30 and 100 square meters; the depth of the molten glass bath is about 1.4 meters (it varies according to the color of the glass, deeper for clear glass, less deep for dark glass). All the external surfaces of the furnace are covered with insulating materials to prevent heat loss. N.B.: see production plant diagrams on page 70 onwards.

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View of feeder pipes for the glass, from the furnace to the machines.

The molten glass is refined at about 1550°C and is then delivered to the forming machines through conditioning feeder pipes. The plant is fuelled with natural gas with a “lower calorific value” of 8150 kcal/ m³ at 15°C and 760 mm/hg. The equipment used for the combustion consists of x burners placed beneath each port. Air is pre-heated by contact with the checkers in the regeneration chamber and enters the furnace through the appropriate channel called a port. Here it mixes with the natural gas supplied by the burners. Gases resulting from the combustion leave the melting chamber through another port and flow through the regeneration chamber, heating the checkers and thus allowing significant energy saving.

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The heat is recovered in two vertical chambers packed with bricks of special refractory material (checkers). Stack gases passing through the checkers heat the refractory bricks to a high temperature; the cycle is reversed by means of an automatic inversion valve every 20-25 minutes. By means of the inversion valve, the waste gases are sucked by a natural or forced draught into the stack and expelled into the atmosphere after filtration. The stack is often made of metal and is about 30 meters high. The temperature of the exhaust gases is around 250-300째C. The furnace is completely automatic and is equipped with the following control, regulating and measuring equipment:

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Two drops of molten glass, checked for weight and shape, are cut and dropped into the molds of the finishing machine.


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• an

automatic machine for controlling the level of the melting tank; it is connected to a regulating and recording instrument; • an indicator and regulator of the air/natural gas ratio; • an indicator of the natural gas flow; • an indicator of the air flow; • a pressure indicator and regulator; • a temperature indicator for the different parts of the furnace; • a temperature indicator for the different parts of the regeneration plant; • etc..

PHASE THREE: WORKING THE MOLTEN GLASS The molten glass passes from the forehearth described above to the feeders which deliver the glass to the forming machines. The feeders are made of electrofused AZS refractory material in the section which is in contact with the glass and of alumino-silicate refractory material in the superstructure. The heating takes place through burners placed on the two sides of the superstructure of the feeders, fuelled with natural gas which is automatically regulated to pre-set temperatures. The molten glass passes from the feeders to special basins with one or more holes. Under these holes a cutting mechanism supported by a plunger mechanism “cuts the gob” into the desired shape and weight at the appropriate temperature for working it. This gob falls by gravity into the blank mold (the distance between the shears and the mold is about 3 meters).

AT THIS STAGE TWO DIFFERENT PROCEDURES CAN BE ADOPTED TO SHAPE THE ITEM: ... PRODUCTION USING THE “BLOW-BLOW PROCESS”... (page 75) The blank mold is mounted in the machine with the mouth of the future container facing downwards and a funnel is positioned on top of it. The gob passes through this funnel to reach the cavity of the mold. After the gob falls, the baffle is fitted onto the upper opening of the funnel, which is conical, fitting perfectly and with the gob inside. The baffle has holes in it to allow entry of the compressed air that will push the gob of glass downwards, causing it to adhere perfectly to the neck-ring and to the plunger. In this way the mouth is formed with the opening facing downwards and with the rest of the gob above it. Then the unit consisting of the baffle and the funnel is moved, and the baffle is

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Two bottles are closed in the finishing mold (above) and two others are waiting to be sent on the conveyor belt to the annealing furnace.


Two bottles are about to be transferred onto the conveyor belt to the annealing furnace, thus leaving room for the two bottles (behind) which are being taken out of the finishing mold.


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Triple gob production: three parisons are about to enter the finishing molds.

placed in the position previously occupied by the funnel, thus closing the cavity of the blank mold. At the same time the plunger is removed. The loss of contact between the glass and the plunger allows the glass, which has already hardened due to the previous contact, to be tempered due to the heat transmitted from the body of the gob. After a short lapse of time, a certain amount of air is introduced through the opening (this phase is known as “counter-blowing”) in order to shape the so-called parison, or semi-finished container. This is obtained by puffing up the gob of glass until it is fully in contact with the surfaces of the blank mold and of the baffle. Once sufficient time has passed, the “counter-blowing” is stopped. Then the baffle is removed and the blank mold is opened, leaving the parison (which is still upside down) supported by the neck-ring alone. At this point the parison, which is gripped round the mouth by the neck-ring mechanism joined to an arm called an inverter, is turned to an “upright” position by rotating it 180°C and is transferred to the finisher. The parison does not get deformed during this operation due to the fact that the surface layer of the glass has hardened slightly, following its contact with the blank mold. This hardened layer, which allows the parison to be inverted, could interfere with the final blowing inside the finishing mold if it were not for the fact that during the period of inversion, when it is not in contact with the mold, the parison becomes

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Three bottles have been taken out of the finishing molds and three (on the right) are being formed in the finishing molds.

viscous again as a result of the heat transmitted by the internal mass of the glass, so that it is in a suitable state to receive the final blowing. Having reached the finishing side, the neck-ring, which consists of two parts, opens, releasing the parison precisely at the moment when the two halves of the blank mold have closed around the neck of the article, below the mouth. It then returns to the blank mold station to start forming another parison. At the finishing station there is a blowhead which positions itself above the mouth of the container, attaching perfectly onto the upper surface of the mold. It introduces compressed air into the semi-finished article, expanding it until it completely fills the cavity of the blank mold. In this phase a considerable amount of heat is removed, and the container becomes hard enough to retain its shape after the removal of the mold. During the final blowing through the bottom, a vacuum is also applied in order to remove the air trapped inside the niches, so as to improve the dimensional precision of the product. A take-out mechanism locks onto the neck of the bottle with grippers, lifts it and takes it to a cooled dead-plate, which has the purpose of removing more heat and of supporting the container when it is released by the transferring device to be pushed onto the conveyor. The molds are cooled by air from suitably directed ventilators.

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Three parisons are about to rotate by 180°C and replace the three bottles that can be seen in the finishing molds (above).

... “PRESS-BLOW” PROCESS... (page 77) The “press-blow” process is identical to the “blow-blow” process, except for the method of forming the parison in the blank mold. The gob is introduced into the blank mold through the funnel, and falls directly onto the tip of a tap that reaches inside the mold through the neck-ring. The height of the tap is set in such a way that on entering the mold the gob fills the cavity almost up to the level of the blank mold. Immediately afterwards, the funnel moves away and its place is taken by the baffle, that closes off the upper part of the blank, as in the blow-blow process. At this point the tap moves upwards by means of a cylinder controlled by compressed air, and distributes the glass inside the cavity in the mold and neck-ring, so that the available space is completely filled. Once a pre-set period of time has passed with the tap in contact with the glass, thus allowing the perfectly formed parison to cool sufficiently, the tap is withdrawn, the baffle returns to the idle position and the blank mold is opened. The parison is then transferred to the finishing mold and the forming cycle continues as in the blow-blow process.

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Bottles taken out of the finishing molds in a double gob machine.

In this process, it is absolutely necessary to keep the weight of the gob within controlled limits. The shapes of the blank mold and of the tap have an essential role in obtaining the final distribution of the glass. If the shape of the blank mold allows easy loading of the gob, and if the temperature of the mold and tap are properly controlled, the “press-blow” process for wide-mouth containers takes place smoothly for both wide and narrow-mouth containers without too many problems. Nowadays the forming machines on which the molds are situated are generally independent section linear machines with 6-8-10-12 sections. For special products, mono-section machines or double-section machines can be used. The sections of a machine should not be confused with the number of glass gobs that are processed in a particular time unit. There are many different combinations: • single

gob (the shears cut a single gob at a time - the basin has a single hole); • double gob; • triple gob; • quadruple gob (today this is the maximum number and it is used to produce small vials for penicillin, for example); • 2 sections/4 sections/6 sections/8 sections, etc..

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A modern ten section, double gob machine.


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An acceptable scheme could be as follows:

SINGLE GOB DOUBLE GOB TRIPLE GOB QUADRUPLE GOB

4 SECT.

6 SECT.

8 SECT.

10 SECT.

12 SECT.

16 SECT.

• • •

• • •

• • • •

• • • •

• •

A manufacturing process involving multi-gob processing is used for longer runs and therefore needs multi-section machines (that generally use the same mold for several days). This is adopted when the furnace and the feeder allow it, in terms of glass tons/day. So production planning represents one of the most important and complex aspects as it is necessary to ensure the compatibility of a whole range of parameters, such as: • maximum • maximum

and minimum capacity of the furnace; and minimum capacity of each feeder (generally 3 or more for each

furnace); of the glass (some items cannot be produced in particular situations); • weight of each article; • forming machine equipment; • type of machine process (blow-blow; press-blow); • state of machine (single-double); • number and state of available molds for each item; • number of changes in the series of molds that technicians can make in a day; • product control systems available in the “cold-end”; • and many others. • state

After forming, the glass articles are sent to the annealing lehr, where the glass temperature is at first increased from 450°C to around 560°C, distributing the heat uniformly around the furnace with the use of special fans, and then cooling it slowly in order to bring the article to room temperature, thus eliminating any surface stress caused in the forming process. This process is called tempering or annealing. See also page 179 point 1.5. The tempering or annealing process lasts around 1 hour.

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Electronic machine for checking the finishes.


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PHASE FOUR: QUALITY CONTROL AND PACKAGING OF THE FINISHED PRODUCT After the item has been treated in the annealing lehr, it is subject to visual inspections or automatic checks in order to verify that it has been properly produced and is of perfect quality.

End of the annealing process and cold treatment carried out with vegetable or synthetic oils.

Automatic checks generally inspect the finish and bottom, and check the appearance of the sides and the size. However, such checks vary from plant to plant and according to the type of item and the color. This phase in the production cycle is again one where the stability of the articles on the production line is important because they are transported by the conveyor belts at high speed and quality controls are carried out as they are moving. Once the inspection has finished, the products are stacked on shelves in several rows and an automatic arm collects a whole row at a time (generally the same size as the pallet, that is 100 x 120 cm) and places them on a previously prepared wood pallet. The aim of a glass factory is to manufacture products in the most hygienic way and keeping breakages to a minimum, so layers of special separators and bottles are laid alternately, one on top of the other, starting from the wooden pallet. When the desired height is reached, everything is covered and wrapped in shrink-wrap polythene, which, when heated, turns the block of glass containers into a single, stable and compact unit that can be safely transported. Starting with this kind of packing, over time different materials have been developed to improve the sliding along of the containers, and cardboard trays have been replaced by plastic separators.

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Area for finish checks and other controls.

Visual control.

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Quality controls in the cold area.

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Pallet loading.

The pallet is ready.

The pallet is wrapped in shrink-wrap plastic film.

For particularly delicate or decorated bottles, a special packaging has been developed that prevents the containers from rubbing against each other, that is, cell-type grids the size of the base pallet into which bottles are placed manually thus allowing safer transportation. The last step consists in fixing a label to the pallet with all the details identifying the articles and the batch. The finished products, packed onto pallets, are wrapped in polyethylene hoods and then drawn into a heat-wrapping furnace, labelled and delivered to the Warehouse after they have been cleared by Quality Control.

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ONE PALLET

1000.0

BOTTLE (ID) Length

80.00 mm

Width

80.00 mm

Height

300.00 mm

Weight

--

Volume

1.04 l

BOTTLE (OD)

1200.0

Lenght

80.00 mm

Width

80.00 mm

Height

300.00 mm

Weight

500.00 g

Volume

1.04 l

UNIT LOAD (INCL. PAL) Lenght

1200.0 mm

Width

1000.0 mm

Height

1389.7 mm

Weight

428.00 g

Volume

1.7 m3

Total number of bottles Area efficiency

108.3%

Cubic efficiency

56.3%

Cases per layer

203

Layers/Load 1389.7

812

Pattern Max UL High Clamp direction

4 Staggered 4 N/A

Industrial pallet 1200 x 100 x 144 mm

1000.0

1200.0

The wooden pallet generally used is a specially fumigated French pallet, with plastic pad under each layer.


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Pallet of bottles with separators to avoid contact on shoulders.

Pallet of jars.

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GLASS PRODUCTION PROCESS

RAW MATERIAL ASSEMBLY AREA

70

MELTING AREA


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HOT END

COLD END

They collect the glass from the refining basin and take it to the machines FEEDER PIPES

FORMING MACHINE

ANNEALING FURNACE

PRODUCTION AREA

INSPECTION

PACKING

With electronic, electromechanical and manual equipment The temperature of the glass is raised and then lowered uniformly

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SECTION VIEW OF A MELTING FURNACE WITH REGENERATOR

Connection tunnel between the heat exchanger and the melting basin

HEAT EXCHANGER divided into two sections which work alternately for 20 minutes each

LOADING OF RAW MATERIAL

TOWER

m STACKS refractory bricks which heat up, taking heat from the outgoing air, and cool down, releasing heat into the incoming air

FUMES/AIR

Connection with chimneys

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MELTING AREA

REFINING AREA

REFINING BASIN OR FOREHEARTH

massa vitrea

glass sent to the machine feeder pipes

THROAT

Point where glass mass passes through to the refining basin

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Blow-blow production process.


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BLOW-BLOW MOLDING PROCESS ON I.S. MACHINE (INDEPENDENT SECTIONS) PRODUCTION STEPS

1. GOB CHARGING

2. BLOWING THROUGH BAFFLE MOUTH FORMING

3. COUNTER BLOWING PARISON FORMING

4. TRANSFER FROM BLANK MOLD TO BLOW MOLD

5. PLACING THE OBJECT IN THE BLOW MOLD

6. THIRD BLOWING FINAL FORMING

7. TAKING OUT

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Press-blow production process.


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PRESS AND BLOW MOLDING PROCESS ON I.S. MACHINE (INDEPENDENT SECTIONS) PRODUCTION STEPS

1. INTRODUCTION OF GOB

2. GOB CHARGING

3. PRESSING AND PARISON FORMING

4. TRANSFER FROM BLANK MOLD TO BLOW MOLD

5. PLACING THE OBJECT IN THE BLOW MOLD

6. BLOWING FINAL FORMING

7. TAKING OUT

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ABOUT MOLDS

The mold (or rather set of molds) is the equipment that, once installed on the IS glass forming machines, allows the glass to be formed into the shape of the container to be manufactured. During the design phase for the molds, it is important to know the physical and mechanical features of the glass in the factory where it will be produced, the technical features of the machines on which the molds will be mounted and the special features of the container (jar or bottle) in order to obtain the best possible result in terms of quality and cost. Normally the set of molds can be divided into three parts; “the blank mold”, “the blow mold” and “the finishing mold”. The “blank mold” or preparatory mold is the fundamental element in the production of the container and needs to be carefully designed in order to ensure the correct loading of the glass gob into the mold and to prepare a parison that will ensure the uniform distribution of the glass in the final forming of the container. The equipment for the blank mold is as follows: • the

funnel that is used to introduce the gob of hot glass falling from the feeder pipe into the blank mold. A good funnel helps to prevent excessive rubbing of the glass in the mold and gives the gob an initial lengthening deformation; • the baffle plate, initially installed over the funnel, is used to convey the compressed air into the blank mold (first blowing), whereas later on, once the funnel has been removed, it will be used to close the mold during the counter-blowing (second blowing); • the finish equipment is made up of the neck, the ring, the plunger and the sheath (the sheath is only used in the blow-blow process) and it is used in both phases of the production cycle. In the first phase, the parison formation, during the counter-blowing the neck and the ring form the finish of the container: the glass fills all the free spaces of the neck, while the ring forms the upper part of the finish and the plunger forms the inside bore. In the second phase, when the item is transferred from the blank mold to the blow mold, the neck serves to support the parison. The “blow mold” is the mold that receives the pre-formed shape or parison obtained in the blank mold, complete with the finish; this undergoes final blowing to produce the final form for the container. Obviously, all trademark engravings or special features on the container correspond exactly to the design of the interior surface of the blow mold. In order to make the glass adhere uniformly to the shape of the mold, during

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the blowing process air is also extracted from inside the mold, and a cooling process takes place to lower the temperature, so that the glass begins to solidify into its final shape. The blow mold equipment is as follows: • the

bottom plate, forming the base of the container from the support points to the punt, engravings etc.; • the blow head, to introduce compressed air, through the finish made in the blank mold, causing the pre-formed shape to expand so that the glass adheres to the sides of the blow mold; • the tongs that lift the container from the blow mold, and place it on the conveyor belt after keeping it suspended for a few seconds to facilitate further solidification and stabilization after the extraction movement.

Preparatory mold double/triple gob for NNPB production (narrow neck press and blow).

Both the blank mold and the blow mold are made of two halves, known as male and female, with hinged openings (see pages 111, 112, 113) to allow the extraction of the pre-formed shape and the finished product. Some products are made with molds composed of 3 or 4 parts, but this is for particularly complex containers with unusual geometrical shapes, undercut angles, etc..

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Small set of preparatory molds.

Mold sets are usually made of cast iron, although for some products, and with the continuing development of new production techniques and innovations in the cooling system, the use of aluminium is also becoming more frequent. Molds for the glass industry are generally produced using chilled cast iron consisting of a core in grey cast iron (that comes into contact with the glass) an interface of cast iron alloy and an external surface of white cast iron.

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Small set of finishing molds.

This exploits the external hardness of white cast iron and the strength and resistance of grey cast iron, which comes into contact with the glass. With the progress of technology, foundries have been producing 3 alloys with different structures that are favoured by glass manufacturers: • Lamellar

graphite chilled cast iron developed for quick cooling, supported by other carefully designed chemical compositions. It is used for high-

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speed production runs. graphite chilled cast iron, which has a structure designed to render the “glass contact” surface particularly compact and easily burnished, making it suitable for perfume and cosmetic bottles and any applications where particular brightness is required. • Vermicular graphite chilled cast iron, which combines the features of the previous two types. Vermicular cast iron, with variable graphite, combines the quality of compactness for the “glass contact” surface with excellent cooling rates (generally suitable for the production of large containers). • Spheroidal

Bronze and nickel alloys can also be used to meet the specific quality requirements of particular parts of the container (e.g. the neck ring and bottom plate) and for faster production, since their high thermal conductivity allows the rapid cooling of the finished container. In order to increase the resistance of the cast iron further, a metallization process is carried out on the matching sections of the mold, the blank and blow mold base plates and the glass contact surfaces of the finish group (neck ring, ring and plunger) using special powders that increase the external hardness of the cast iron.

MELTING TEMPERATURE (C°) FOR IRON AND CARBON

IRON/CARBON DIAGRAM

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PREPARATORY AND FINISHING MOLD 1. Preparatory mold for Alex Oil 250 ml bottle. The glass gob comes from the feeder, falls into the mold and a small tap comes up and creates the internal calibrated finish. Through the blowing process, it creates a preparatory model of the bottle (a parison), which is then ready to be transferred into the finishing mold.

2. Finishing mold of the Alex Oil 250 ml bottle. In this mold, the parison (as shown above) is blown and aspirated so that the glass adheres almost entirely uniformly to the walls of the mold.

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NOTES ON THE PROCESS OF GLASS DECORATION

The term glass decoration means modifying the appearance of the container with a second processing. There are different ways to decorate glass. The most commonly used methods on bottles and jars are silk printing, sandblasting, acid frosting and painting.

SILK-SCREEN PRINTING This term comes from the combination of the Latin word “seri” (silk) and the Greek term “γράφειν” (write), so silk-screen literally means “writing on silk” because this kind of technique was used the first time on silk. Silk-screen printing is a technique which was introduced in the United States during the Thirties; it makes it possible to reproduce an image on glass and allows the superimposing of different layers of color, creating a very similar effect to the original artwork.

PROCESSING PHASES A. The artwork is separated into the different colors to be reproduced. B. The block, a rectangular-shaped wooden or steel frame, is prepared by attaching a piece of silk or steel micro-mesh, more or less densely woven according to the desired level of resolution.

C. The required image is reproduced on the frame by treating the parts of the micro-mesh which the color must not pass through (the negative) with a special gel, which is then dried.

D. Color selection. The colors can be ceramic, organic, UV or precious met-

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als. The most widely used colors for silk-screen printing are ceramic colors. Ceramic enamels are heated at 500-600°C. At this temperature, the glass molecules start to separate and in this way the glaze-based product is trapped and permanently fixed. The chemical formula of these enamels includes the use of heavy metals such as lead, cadmium, hexavalent lead and mercury to make the colors bright and glossy. However, in many countries (e.g. Germany and the USA) legislation governing environmental protection and toxic waste disposal prohibits the use of heavy metals. The elimination of heavy metals from ceramic enamels means that the desired colors cannot be obtained, and for this reason technicians have turned to other solutions such as organic colors and UV


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inks (in this case the colors are dried by means of UV ray lamps, but this kind of ink does not work well on glass). Since 1st July 2000, the PPM of heavy metals cannot exceed 100 PPM and this already low limit is destined to become even lower. This is an overall limit, so it includes any heavy metal elements already present in the glass. Glass can also be decorated with precious metals (gold and platinum). Precious metals do not incorporate into the glass structure but remain on the surface, thus creating a metal foil. For this reason, in planning the final product it is important to take into account the treatment used by the glass manufacturer on the polished glass. If organic colors or precious metals are used, there could be problems in the poor adherence of the color to the glass and/or chemical alterations (e.g. the gold may change color and become almost red).

E. The frame is fitted with an electricity-conducting system to allow the melting of the flakes of glaze with colored pigments.

F. A spatula runs across the frame exerting a slight pressure, transferring the color and therefore the prepared image onto the container.

G. When precious metals are used, the heat causes the turpentine and the solvent to volatilise, so that only the metal passes through the silk and is transferred onto the container.

H. After the silk-screen printing, the containers are heated at 550째C in the case of gold and at about 600째C for other materials.

ADDITIONAL INFORMATION ABOUT SILK-SCREEN PRINTING Precious metals (gold, platinum) do not incorporate with the molecules of glass. Instead, they deposit on the glass where they form a metal foil. For this reason, it is better to use untreated containers since when the material is re-heated, the treatment materials tend to volatilise and therefore the metal does not adhere perfectly to the container. This does not mean that treated containers cannot be silk-screen printed with gold. It merely means that it is necessary to check whether the products to be used inside the container will corrode the silk-screen image (as in the case of vinegar). The supplier of the silk-screen printing should submit the process to a range of technical tests (applying the product to it, rubbing and so on), and will then be able to advise the customer accordingly. WARNING: Silk-screen printing in gold and platinum will oxidise.

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It is important to bear in mind that the results may be different depending on the processing method used by the supplier. For example, precious metals will produce a shiny effect if they are transferred to an untreated container, while a matt effect will be obtained when the container has previously undergone a frosting process with acids. It is possible to obtain a shiny effect with gold on a frosted surface by carrying out an additional process, that is to say by providing a shiny support base (foundation) on which the silk-screen printing will be applied. In this case, two types of process must be carried out, and therefore the cost will be higher. There are several parameters to keep in mind when calculating the cost of a silk-screen printing operation: • the

quantity ordered • the shape of the container • the final use of the finished container • the color of the glass • the pressure at which the container will be used • the size of the required silk-screen printed image • the position of the image on the container • the number of colors required • the type of color required (normal or precious metals) • the required thickness of the color (e.g. the cost of gold varies a great deal depending on the thickness of the layer). It is extremely important to ask the customer for as much information as possible, so that the processing procedures and above all the feasibility of what is being requested can be carefully evaluated. When a silk-screen printed product is sold, it is important to keep in mind that several different types of procedure are possible, depending on its shape. For instance, to silk-screen print a cylindrical bottle using a single color, only one color-stage is required, while two stages, and perhaps even two curings will be required for a square bottle. It is necessary to know beforehand what the object is for and how it will be used by the customer, so as to be able to determine which products to use, which checks to conduct and, above all, how the printing will be carried out. For example, if containers are designed to contain a liquid under pressure, they must be decorated using a procedure which does not affect their pressure resistance and it will be up to the decorator to establish if these features will be preserved or not. If, on the other hand, they are to be used for products containing aggressive chemicals or acids (e.g. vinegar), they will need to be processed in such a way that the decoration is not damaged by the contents (causing it to oxidise or even disappear). Special processing such as frosting with acids may be carried out on the polished parts, onto which the silk-screen printing is to be applied.

86


2. LOOKING INTO GLASS

CNC Machine with 8 UV colors for silk-screen printing.

UV ink decoration, view of the frame and application of the color.

Methods of procedure: • Application

of a “label” on the container, which serves to protect the areas to remain polished. • Drying the “label” at 120°C. • Acid frosting of the container. • Kiln heating at about 200-300°C to singe off the “label” so that the container will be frosted leaving a polished area. • Silk-screen printing of the polished area using special centring equipment. When more than one color is used (four-color process), it is possible to obtain different effects by applying the colors in different sequences. For example, if the first stage of color is white, it can enhance the depth of the image. Advice about this can be provided by the production technicians.

87


2. LOOKING INTO GLASS

SANDBLASTING Sandblasting is a process used for special types of decoration. It is obtained by blasting the glass with powdered corundum at a high pressure, from a particular angle. The sand marks the glass surface, producing a porous effect. The grain-size of the sand determines the resolution of the results. It is possible to use masking plates when sandblasting, so as to leave some polished areas on the container. This type of processing may affect the physical structure of the container (micro-cracks).

88


2. LOOKING INTO GLASS

ACID FROSTING PROCESS Acid frosting is carried out by dipping the containers into special tanks containing: • Water • Hydrofluoric

acid bifluoride • Barium bisulphate • Ammonium

The frosting can be carried out up to the rim of the bottle by placing a special rubber cap on the mouth of the bottle and submerging it completely in the acid. This is a delicate operation, since some acid might enter the container, and there is a risk of contamination of the interior despite the final washing. Frosting to below the finish is the most advisable system, since the bottles are only immersed up to this level.

Frosting machine.

It is also possible to leave a “window” in the frosting area, that is, a part of the container that remains polished or with a polished effect. This result may be obtained in two different ways: • A mask is created by silk-printing the part that has to remain polished using the

appropriate materials. The container is immersed in the acid (the silk-printed area will be protected from the acid), the mask is washed and then the container is heated in the furnace;

89


2. LOOKING INTO GLASS Large machine for acid frosting.

90


2. LOOKING INTO GLASS

91


2. LOOKING INTO GLASS

Checking of frosted bottles.

• The

“window” area is created by silk-printing the completely frosted bottle using a special material which makes the selected part of the bottle polished again. In this case silk-printing is carried out directly on the frosting and not on the original glass, so the transparent effect will not be so clear.

After the frosting process the containers are washed, using about 10 litres of water per bottle, which is then recovered and recycled. N.B. A new decoration technique is currently being developed to overcome the environmental and safety problems involved in acid frosting. This is a powder painting technique called “white coating”, which closely resembles conventional frosting and makes the surface of the container feel very smooth. Bottles treated in this way can be cold screen-printed at around 80°C and proper curing enables the resins to bond perfectly with the coated surface. This technique does not affect the glass structure and, therefore, is particularly suitable for the decoration of bottles where high internal pressure resistance is required.

92


2. LOOKING INTO GLASS

PAINTING Painting of course consists in covering the container with a layer of paint. Paints for glass decoration are used in the cosmetic and household sectors but also in the food industry. They are organic-based and can be classified as: • water-based

organic paints; powder paints (made up of resins and pigments that can contain varying percentages of heavy metals).

• organic

They are applied to the bottles using electromagnetic charges and are then cured at about 200°C. Since they are organic products, they are subject to ageing, so significant changes in temperature or storage in a damp place might cause the paint to crack or flake. Customers should therefore be reminded to store the painted bottles in a dry place. Transparent colors have greater mechanical strength than those with an opaque or frosted appearance. Painted bottles may also be silk-screen printed, but the procedure and materials used are completely different, with the use of fluid inks cured at low temperatures. Metallization is a particular type of painting decoration, and results in bright, shiny glass. Another technique directly linked to these two procedures is “laser removal” which consists in removing part of the paint (or metallization) in order to achieve the required decoration. For all these processes, it is necessary to allow for about 5% waste.

93


From left: Opaque black paint coating with matt finish; glossy white paint coating + light finish; gloss paint finish, silk-screen 2. LOOKING INTO GLASS printing, hot printing in silver, decal decoration and label.

OTHER TECHNIQUES In addition to the techniques described above, there are other less frequently used methods: • Pad-printing:

this printing procedure uses a pad to transfer ink onto the glass container. This is a surface decoration so only organic colors are used; • Decal: a printing procedure where a sticky label with the required decoration is applied to the bottle. It can be used at high or low temperatures and is generally used to decorate specific bottle areas which cannot be decorated with silk-printing;

94


2. LOOKING INTO GLASS

• Hot

stamping: a lithographic dry printing process whereby fine layers of metal foil are transferred on the glass surface at high temperatures.

Finally, there is 3D Printing and Sublimation: these are sophisticated techniques which are used mainly for perfume bottles. Clearly, there is a whole host of possibilities to consider for the decoration of glass containers. In conclusion, the procedures described above can also be used in combination and can transform an ordinary container into a unique, extraordinary product.

95


Checking of bottle prototype for Crystal Head Vodka.


DESIGNING CONTAINERS

DESIGNING A BOTTLE 1. THE CAPACITY OF A BOTTLE

page 100

2. THE GLASS WEIGHT

page 101

3. CALCULATION OF THE VOLUME OF THE BOTTLE

page 102

4. THE FINISH

page 103

5. STANDARD NECK FINISHES

page 104

6. CUSTOMIZED OR SPECIAL NECK FINISHES

page 105

7. SIZE LIMITS

page 106

8. DESIGN

page 107

9. THE NECK OF THE BOTTLE

page 108

10. THE BOTTOM OF THE BOTTLE

page 109

11. ORIENTATION MARK

page 110

12. SPECIAL SHAPES

page 111

13. ANATOMY OF A BOTTLE

page 114

14. DESIGN SKETCH

page 115

DESI GN ING


540째C - bottle and jar.


15. TECHNICAL DRAWING

page 116

16. THINGS TO AVOID

page 117

THE DESIGN OF A JAR 1. THE CAPACITY OF A JAR

page 119

2. THE GLASS WEIGHT

page 120

3. CALCULATION OF THE VOLUME OF A JAR

page 121

4. THE FINISH

page 121

5. STANDARD FINISHES

page 122

6. DESIGN

page 123

7. SIZE LIMITS

page 123

8. ORIENTATION MARK

page 123

9. THINGS TO AVOID

page 123

10. DESIGN SKETCH

page 124

11. TECHNICAL DRAWING

page 125


3. DESIGNING CONTAINERS

THE CAPACITY OF A BOTTLE

The capacity of a bottle can be either its nominal capacity or its brim capacity. • The

“nominal capacity” is the “commercial” capacity, requested by the customer, and measures the quantity of liquid that the container will hold.

• The

“brim capacity” is the total technical capacity of the bottle. It is obtained by measuring the amount of “empty space filled with air” from the fill level up to the brim level (on average 3% of the nominal capacity) and adding this to the nominal capacity.

The fill level is the level on the neck of the bottle that the liquid will reach once the container has been filled. Between this level and the top of the bottle there is an air space and space for fitting the cork, if required. The air space varies according to the closing system, the filling process and the product inside.

100


3. DESIGNING CONTAINERS

THE GLASS WEIGHT FOR BOTTLES

The glass weight of a bottle is determined by its shape, whether round or other shapes, its capacity and the total number of items to be produced. As a rule, a bottle with a special shape will require a higher glass weight because of the difficulty of distributing the glass uniformly; obviously, a bottle with a capacity of 750 ml will require a greater glass weight than one with a capacity of 250 ml, due to the larger surface volume. The quantity of items to be produced may influence the design of the set of molds (e.g. a very large quantity will entail a higher cost for the equipment in absolute terms, but will allow a more sophisticated design of the molds, which may result in a reduced glass weight). The following table showing glass weights in relation to the capacity and shape of the items is merely indicative. It must be stressed that the higher glass weight required by non-round bottles compared with round bottles serves to increase strength in the critical areas (e.g. on the sharp edges on the bottom or flat shoulders, etc.).

ROUND SHAPE

SPECIAL SHAPE

Nominal capacity cc

Glass weight gr

Nominal capacity cc

Glass weight gr

200

220 / 250

200

300 / 350

250

250 / 300

250

300 / 350

350

300 / 400

350

400

375

350 / 400

375

400

500

400 / 500

500

500 / 600

700

500 / 550

700

600

750

550 / 600

750

600 / 700

1000

650 / 700

1000

700 / 750

101


3. DESIGNING CONTAINERS

CALCULATION OF THE VOLUME OF THE BOTTLE

To calculate the total volume (and therefore the outside surface area of the container) it is necessary to know the brim capacity of the container, the volume occupied by the glass and the “shrinkage” of the glass after cooling. E.g.: bottle with a nominal capacity of 750 ml, glass weight 600 gr * brim capacity cc 770 ** volume of glass cc 240 (600 gr ÷ 2.5) *** glass shrinkage cc 12 (~1.2% of [770 + 240]) ________ ml 1022 TOTAL VOLUME TO BE OBTAINED * The brim capacity is calculated by adding the air space above the fill level to the nominal capacity (see page 100). ** The volume of the molten glass is obtained by dividing the glass weight in grams (see page 68), by the specific weight of glass, which is 2.5 kg/dm³. *** The shrinkage of glass is calculated to be ~1.2% of the total volume (brim capacity + volume of glass).

102


3. DESIGNING CONTAINERS

THE FINISH

This is one of the technical limitations that a designer has to take into account when creating a design. As a rule, customers want the container to be sealed using caps and machinery normally available on the market. In the majority of cases, finishes are standardized at an international level, and therefore the finish size determines the diameter of the neck onto which it is to be applied. Below are some drawings of standard finishes as guidelines to make the design process as realistic as possible. Of course “imaginative” finishes are also possible. In this case, however, attention must be paid to the ratio between the outside dimensions of the finish and the diameter of the neck, which may not exceed 1.3 (maximum 1.4). The reason for this is to prevent the problems caused by a mass of glass that would not cool easily, with a consequent “lack of stability” of the through-bore of the container. In almost all containers for industrial use, the finish is in line with the central axis rather than being displaced sideways. This is due both to production issues (problems relating to the distribution of the glass) and to issues due to the reduction of the maximum diameter that can be produced by the machines. Indeed, the extent of the displacement of the finish from the central axis of the bottle has to be deducted from the maximum size that can be produced using the planned mold. For example, if the maximum size is 100 mm in diameter, the finish will normally be at a distance (or radius) of 50 mm from the walls of the bottle. If one wishes the finish to be out of alignment with the axis, it is not the finish that is actually moved. Rather, it is part of the bottle wall that is brought closer to the finish (see the drawing on page 104). As you can see, the design of the mold always has the finish on the theoretical axis. It is the “glass wall” that is brought closer.

103


3. DESIGNING CONTAINERS

STANDARD NECK FINISHES

P.P. 31.5 MEDIUM (OIL BOTTLE)

P.P. 31.5 LONG (SPIRITS BOTTLE)

P.P. 28 MEDIUM (OIL BOTTLE)

P.P. 28 LONG (SPIRITS BOTTLE)

P.P. 24 MEDIUM (OIL BOTTLE)

P.P. 18 MEDIUM (OIL BOTTLE)

BVS-STELVIN (WINE BOTTLE)

METALPLAST (SPIRITS BOTTLE)

GUALA 1031 (SPIRITS BOTTLE)

GUALA 550 (SPIRITS BOTTLE)

104

CETIE (WINE BOTTLE)

THREAD (WINE BOTTLE)

CROWN CAP (SPUMANTE AND BEER)


3. DESIGNING CONTAINERS

CUSTOMIZED OR SPECIAL NECK FINISHES SPEC. FRAGRANCE

WITH SPOUT

SPEC. CORK

FLANGE

PERFUME

RING

MECHANICAL CAP

BETS

105


3. DESIGNING CONTAINERS

SIZE LIMITS FOR CONTAINERS

When designing an article, it is necessary to consider not only its shape, due to the limitations set by the opening of the mold, but also the limitations of the maximum overall size, again in terms of the molds, which vary depending on the item produced, with double or single gobs, and in terms of the features of the forming machine. The following table gives indicative maximum permissible limits for double and single gob production using the most widespread machines (I.S. - Independent Section, 4”¼ or 5”½).

DOUBLE GOB 4”1/4 A max F max H max

88 mm (*) 85 mm 309 mm

DOUBLE GOB 5”1/2 A max F max H max

115 mm 105 mm 320 mm

SINGLE GOB 4”1/4 A max F max H max

160 150 400

The limits in height refer to the actual bottle, that is to say, excluding the height of the neck-ring (mouth) which may be considered to be about 21.8 mm. A max means: • the maximum diameter of the body for round bottles; • the maximum width allowed for the body, for bottles of special shapes (*); • the maximum diagonal on which the mold is opened for rectangular or square bottles. F max means: as above, but with reference to the size of the base, which is normally smaller so as to allow the rounding of the connection to the body. This is because sharp edges create flaws. H max means: the maximum permissible height from the bottom up to the base of the neck (excluding the neck-ring).

106


3. DESIGNING CONTAINERS

DESIGN OF A BOTTLE

Many different ideas may give birth to a new design, but in particular they tend to provide answers to aesthetic requirements, and then to offer novelty and meet new production needs, improving the practical operation of the lines. In any case, before tackling a project, the final targets must be clear, i.e. the intended use of the container (wine, oil, distilled products), the quality or the message that the container should convey to the possible customers, its capacity, the type of closure and so on. Other aspects concern the handling/use of the finished product, such as the size of the shelves in a supermarket (which determine the maximum height of about 320 mm) and so on. Then there are all the factors concerning the client who will be filling the bottle, such as the application of the label and its shape, the need to have space with a bending radius which allows easy application, any engravings required on the glass, the type of filling line used and the type of closure required. In addition, there are factors concerning the bottle manufacturer, such as the glass weight, the size of the bottle and the type of machine on which it will be produced (distance between centers 4�1/4 or 5�1/2 or something else, and so on).

107


3. DESIGNING CONTAINERS

THE NECK OF THE BOTTLE

One aspect to consider is the aesthetic aspect, of course: that is whether it should be slim-lined or compact, whether it should have a rustic look evoking a natural farm product or if it is an alcoholic drink that requires a more elegant style of pouring. This is a complex aspect involving aesthetic and marketing factors, that comes to a crux, and finds its limitations, in the type of closure. A bottle sealed with a cork, for example, requires a neck that is long enough to contain the cork and some air space between the cork and the product, because in certain temperature conditions the contents may expand in volume. In the case of oil or vinegar, a screw-on cap may be chosen and therefore, since nothing has to be inserted into the neck, it can be much shorter or it may be long simply for aesthetic reasons. Once the top has been chosen, this will determine the maximum diameter of the neck, at least with regard to the bottom, where it has to connect with the finish or neck-ring (see page 69, with drawings of finishes showing some of the dimensional elements). Some designs may include sharp edges where the neck connects to the shoulder of the bottle. This should be avoided whenever possible, since it causes production problems and may also lead to frequent breakages.

108


3. DESIGNING CONTAINERS

THE BOTTOM OF THE BOTTLE

As already indicated in the table showing the maximum sizes (page 106), it is advisable to have at least a slight rounding of the connection between the body of the bottle and the bottom, in order to avoid flaws in the finished product. Sharp corners are not appropriate in glass manufacture. The rounding of the connection may be only slight, but it is important that it is there. Normally there is also a ring with knurling on the bottom of the bottle. The purpose of this is to avoid sudden changes in temperature when the bottle is taken out of the finishing mold and placed on the conveyor belt to be taken to the annealing lehr. During the bottling phase, this knurling or stippling (in relief) increases the stability of the bottle as it moves through the various phases of the process. The bottom may be flat, or it may have a slight or more marked punt. There are both aesthetic and technical reasons for this. In the past, the purpose of the “punt� was to provide an area where the wine sediment could concentrate. Nowadays, a good punt provides greater resistance against any pressure accumulating in the product (with sparkling wines, for example). Punts are not often used in industrial containers produced in large quantities, because this can entail a slightly higher glass weight and therefore a slight slowdown in the speed of production at the bottle factory. In any case, if one wishes to design a container with a punt, it is always best to allow a soft curvature in the connection between the bottom of the bottle and its body, and also between the bottom and the punt itself, which can have a maximum height of 40 mm for single-gob production, while for double-gob production the maximum height is 35 mm. It is possible to choose more pronounced features when designing a bottle (e.g. a 50 mm punt), but the aesthetic benefits should be weighed against the higher production costs entailed.

109


3. DESIGNING CONTAINERS

ORIENTATION MARK

The “orientation mark” is a technical feature which is created in different ways depending on the features of the labelling machines and/or the decoration of the container. The “orientation mark” is made in order to place the container - which is moving fast on the production lines - always in the same position or on the same side, opposite the machine which carries out particular operations: for example, sticking the label exactly under the printed logo or decoration on the bottle. The “orientation mark” can be on the body or the bottom of the container.

BOTTOM ORIENTATION MARKS

MARK

SLIDE

POINT

BODY ORIENTATION MARKS

DOUBLE SLIDE

110

SINGLE SLIDE

MARK


3. DESIGNING CONTAINERS

SPECIAL SHAPES

Of course, in addition to the traditional round bottle, any other shape is acceptable provided that it can come out of the mold, which, as we have seen, normally consists of two half molds that rotate on a fixed hinge. In the case of single gobs, the maximum mold opening radius is 65°C with a minimum distance from the rotation hinge of 165.1 mm (see diagram A). In the case of a double gob on a 4”1/4 I.S. machine, the maximum opening radius is 65°C with a minimum distance from the rotation hinge of 111.1 mm for the inner mold and 219.1 mm for the outer mold (see drawing B on page 112). In the case of double gobs on a 5”1/2 I.S. machine, the maximum opening radius is 65°C with a minimum distance from the rotation fulcrum of 127.5 mm for the inner mold and 266.5 mm for the outer mold (see diagram C on page 112). We also include some drawings (cross-sections) of shaped bottles, in which you can see that in some cases the axis of the opening of the mold passes through the horizontal axis of the cross-section of the bottle. In the case of a square or rectangular bottle, it passes through the diagonal, partly in order to avoid leaving join marks on the flat surfaces and therefore to improve the part of the bottle on which the label can be applied (page 80).

DIAGRAM A I.S. MACHINE SINGLE GOB 4”1/4

BOTTLE

MOLD

A 65°C

111


3. DESIGNING CONTAINERS

DIAGRAM B I.S. MACHINE DOUBLE GOB 4”1/4

BOTTLE

MOLD

54 108 54

.1 65 R1

65°C

DIAGRAM C I.S. MACHINE DOUBLE GOB 5”½

R1

96. 9

69.85

139.7

69.85

BOTTLE

60°C

112

MOLD


3. DESIGNING CONTAINERS

EXAMPLES MOLD OPENING MOLDOF OPENING MOLD OPENING MOLD OPENING MOLD OPENING

S MOLD OPENING MOLD OPENING S

R

S MOLD OPENING MOLD OPENING S

MOLD OPENING MOLD OPENING

MOLD OPENING MOLD OPENING

L MOLD OPENING MOLD OPENING

L MOLD OPENING MOLD OPENING

R

R

R

R

R

A.A.S

A.A.S

A.A.S

A.A.S

A.A.S

R

R

A.A.S

R

L

R

L

R

R

L

R L

R

L R

L

R

MOLD OPENING ROTATION MOLD OPENING ROTATION HINGE HINGE

MOLD OPENING ROTATION MOLD OPENING ROTATION HINGE HINGE

A.A.S

MOLD OPENING ROTATION MOLD OPENING ROTATION HINGE HINGE

A.A.S

MOLD OPENING ROTATION MOLD OPENING ROTATION HINGE HINGE

MOLD OPENING MOLD OPENING

MOLD OPENING MOLD OPENING

MOLD OPENING MOLD OPENING

MOLD OPENING MOLD OPENING

MOLD OPENING MOLD OPENING

S OPENING S MOLD MOLD OPENING

R

L

R

R

L

A.A.S

A.A.S

A.A.S

L

R

A.A.S

L

L L

D

L

D

D D

D

D

S

S

L

D

MOLD OPENING MOLD OPENING

D

MOLD OPENING MOLD OPENING

A.A.S

A.A.S

A.A.S

MOLD OPENING ROTATION MOLD OPENING ROTATION HINGE HINGE

MOLD OPENING ROTATION MOLD OPENING ROTATION HINGE HINGE

MOLD OPENING ROTATION MOLD OPENING ROTATION HINGE HINGE

A.A.S

MOLD OPENING ROTATION MOLD OPENING ROTATION HINGE HINGE

113


3. DESIGNING CONTAINERS

ANATOMY OF A BOTTLE

2

7

6

3 8

1

18

5

4

17

19

21 9

20

10 11 22 12 23

23 23

114

13

13

26

16

14

25

24

15

1. MOUTH DIAMETER 2. SEALING SURFACE 3. CROWN CORK FINISH 4. SCREW FINISH 5. SQUARE BEAD CORK MOUTH 6. FLAT CORK MOUTH 7. TUCK-UNDER RING 8. ANNULUS 9. NECK 10. NECK SHOULDER JUNCTION 11. SHOULDER ROUNDING 12. BOTTLE NECK DIAMETER 13. BODY 14. NOTCH 15. STANDING BASE 16. PUNT 17. NECK DIAMETER AT PARTING LINE 18. THREAD 19. FINISH BAND 20. NECK BULGE 21. LOWER BORE DIAMETER 22. SHOULDER 23. BODY DIAMETER AT SHOULDER 24. BODY DIAMETER AT BASE 25. BOTTOM PLATE ROUNDING 26. PUNT


3. DESIGNING CONTAINERS

DESIGN SKETCH

115


3. DESIGNING CONTAINERS

TECHNICAL DRAWING

116


3. DESIGNING CONTAINERS

THINGS TO AVOID

SHARP CORNERS

EXCESSIVE HORIZONTAL PLANES

ANGLED NECK

INVERTED SHOULDER TAPER

MECHANICAL COUPLING BETWEEN BOTTLES OR WITH OTHER MATERIALS

EXCESSIVELY DEEP PUNT

117


3. DESIGNING CONTAINERS

THINGS TO AVOID

THE VERTICAL PROJECTION OF THE BOTTLE AXIS MUST BE INSIDE THE DIAMETER OF THE NECK

EXCESSIVE TAPERS OR OVERLY NARROW BASES MAKE THE BOTTLE UNSTABLE IN AUTOMATED INDUSTRIAL PRODUCTION

MALFORMED PUNT

EXAGGERATED CURVES MAKE THE BOTTLE UNSTABLE AND DIFFICULT TO USE ON FILLING LINES

AN EXAGGERATED WIDTH HINDERS THE CORRECT DISTRIBUTION OF THE GLASS AT THE EDGES

118


3. DESIGNING CONTAINERS

THE CAPACITY OF A JAR

There are established capacities for jars and these affect the percentage of air that is determined appropriate, unlike heat treatments, that take place after the filling process; generally in the case of jars subject to pasteurization at a temperature of 90째C or lower, the air chamber will be about 5%, while in the case of sterilization, which takes place at temperatures above 100째C, the air chamber should be about 9%. To make this technical issue easier to grasp, we can take the example of a jar with a nominal capacity of 314 ml (corresponding to the brim capacity) and subject to sterilization. The content must not exceed 286 ml, which is calculated by subtracting 9% (28 ml) from 314 ml.

314 ml

119


3. DESIGNING CONTAINERS

THE GLASS WEIGHT

The glass weight of jars, as for bottles, is determined by the container shape and by the total number of pieces to be manufactured. However, there is another important aspect to be considered in the selection of the ideal glass weight for production: in order to avoid the thermal shock of the processes of filling, pasteurization and sterilization, the production is generally carried out using the minimum glass weight possible. Below is an indicative chart with glass weights according to the item capacity and shape. ROUND SHAPE

120

OTHER SHAPES

Nominal capacity cc

Glass weight gr

Nominal capacity cc

Glass weight gr

106

85 / 95

106

115 / 125

156

95 / 105

156

120 / 130

212

115 / 125

212

145 / 155

314

155 / 165

314

185 / 190

370

165 / 175

370

210 / 215

390

170 / 180

390

215 / 220

580

250 / 260

580

315 / 320

720

295 / 305

720

370 / 380

770

315 / 325

770

395 / 405

850

345 / 355

850

435 / 440

1062

365 / 375

1062

460 / 470


3. DESIGNING CONTAINERS

CALCULATION OF THE VOLUME OF A JAR

In order to calculate the total volume it is essential to know the volume occupied by the glass + the “shrinkage” of glass during the annealing process. For example: a 314 ml jar, glass weight 160 gr * nominal capacity cc 314 ** glass volume cc 64 (160 gr / 2.5) *** glass shrinkage cc 4.5 (~1.2% of 314 + 64) __________ ml 382.5 TOTAL VOLUME * The nominal capacity for jars corresponds to the brim capacity. ** The molten glass volume is determined by glass weight in gr divided by specific glass weight (2.5 kg/dm³). *** The glass shrinkage is calculated as ~1.2% of total volume (brim capacity + glass volume).

THE FINISH

During the delicate phase of designing a jar, the finish plays an essential role because this determines the jar diameter, including the stacking step diameter, which is indispensable for obtaining good stability of the jars on shelves. For these reasons, when designing jars of the same shape, it often becomes difficult to achieve the same proportions with different capacities. The use and above all the contents of the jar require different solutions for the selection of the finish: for sauces or similar products, a 27 to 38 twist-off cap is suitable, while for baby artichokes or mushrooms in oil, the 110 twist-off is selected because it allows easy manual access to the inside of the jar that would be difficult with a smaller diameter. This necessity is imposed by the need for the products to be manually placed inside the jar by the filler. Finally, for the small jars used for anchovies, the finish is almost always a 45 Pano cap.

121


3. DESIGNING CONTAINERS

STANDARD FINISHES FOR JARS

TO 27-38 (3 TEETH FOR SAUCES)

TO 43-48 (4 TEETH WITH LOCK FOR SAUCES AND PRESERVES)

TO 77-100 (6 TEETH FOR PRESERVES)

TO 43-70 (4 TEETH FOR PRESERVES)

VITE 80 (FOR HONEY)

PANO 45 S (FOR FISH PRODUCTS)

TO 43-82 DEEP (4 TEETH FOR PRESERVES)

TO 110 (8 TEETH FOR PRESERVES)

PANO AK 103 (FOR READY-MADE DISHES)

122


3. DESIGNING CONTAINERS

DESIGN

In designing a jar, it is essential to follow precise guidelines. • In

order to prevent the jars from colliding with each other at the lid, thus causing the loss of air space inside the jar, it is essential that the maximum diameter of the jar is sufficient to protect the lids from possible collisions on the production line. • The labeling area must not be too small in size, preferably no less than 20 mm usable height for jars of capacities ≤ 60 ml, while for larger capacities it should not be less than 40/45 mm of usable height. If the label is applied with water and glue, a label protector should also be used, while this is not necessary in the case of adhesive labels. This is because the thickness of the glue and remnants of it may lead to contact between labels and cause their accidental removal. • As regards the shape of the jars, it is always advisable to avoid corners or critical surfaces where jars may come into contact with each other on the labeling machines or conveyor belts, also in order to avoid the accumulation of the product in corners of the jar where the final user is unable to retrieve it easily. • The height limitations are determined by the need to ensure good stability of the jar, unlike bottles, which do not generally exceed 330 mm (the height of the shelves).

SIZE LIMITS See page 106

ORIENTATION MARKS See page 110

THINGS TO AVOID See pages 117-118

123


3. DESIGNING CONTAINERS

DESIGN SKETCH

124


3. DESIGNING CONTAINERS

TECHNICAL DRAWING

125


Some of the participants from previous editions of the Millennium Project.


4

A SHOWCASE FOR YOUNG DESIGNERS

BRUNI GLASS DESIGN AWARD 1. BRUNI GLASS DESIGN AWARD 2. DUE FONDOS 3. TIMELESS 4. BASSIN

5. ARC 6. SIN

7. MODULOR

8. BACCHIPECTUS 9. CALIGULA 10. PILAR

11. TIPSY

12. TULIPANO 13. SLANCIO

N.B.: The experiences described here have already been published on our website and in the leaflet of the 11th Edition of Millennium Project.

page 128


BRUNI GLASS DESIGN AWARD The Bruni Glass Design Award is a biennial design contest for the creation of glass containers for food products using hollow glass technology. This contest is aimed at students from some of the European Universities of Design and can be considered a genuine workshop where the company and educational institutions work together to transform the dreams and aspirations of young designers into a real working opportunity.

HISTORY The origins of this contest date back to 1997, when Bruni Glass launched their “Millennium Project�, inviting young European students to challenge the turn of the century with new forms of packaging. The enthusiastic response engendered by the contest led the company to extend the contest to other institutions and to increase the number of categories in the contest. From 2013 onwards the contest has been called the Glass Design Award and has become a permanent international contest.

FROM THE IDEA TO THE GLASS PRODUCT The contest lasts for 8 months and is divided into 3 main sections where projects are subject to discussion and amendment. The 20 finalist projects are finally submitted to the judgment of the public at some important trade exhibitions. All the finalist projects are registered and patented by Bruni Glass. Many of these projects - as you will see in the following pages have been manufactured and went on to become distinctive features of some food industry brands.

128


129


DUE FONDOS

Nadine Podewski University of Art and Design Halle - Burg (D) Millennium Project 2009

I think that the competition event is very interesting for students, as they have the opportunity to get real “working� experience in a company. The project can be followed right from the beginning up to the creation of the final product and this is enormously important as a reference for the professional future of a young designer. During their studies, many projects - which may be very good - cannot be marketed since it is very difficult for a student to have access to companies that are willing to manufacture the product. Bruni Glass showed great confidence in students and this gave me the strength and the necessary self-confidence to implement my ideas. It was a very positive cooperation that will be hopefully repeated in other companies.


TIMELESS

Irina Huhnlein Les Ateliers (FR) Millennium Project 1999

My name is Irina Hühnlein and I am currently living in Berlin, where I am working as a freelance product-designer. Before this I studied and worked in Paris for ten years. In 1999, during my first year at the ENSCI-Les Ateliers design school, I participated in the Millennium Project with my design, “Timeless”, in the category of oil bottles. Since then, I have been receiving royalties for the production of this bottle. These royalties helped me during my studies and still support my professional ambitions today: my main interest is in designing products for children using sustainable processes and materials. Participating in the Millennium Project competition was a great experience and led to my collaboration with “Bruni Glass”, which has now lasted for over ten years. I wish you every success in the continuation of Millennium Project.


Karina Wendt University of Art and Design Halle - Burg (D) Millennium Project 2009


Yamada Midori University of Art and Design Helsinki (FIN) Millennium Project 2005


SIN

Adi Fainer IED (IT) Millennium Project 2000

The project was fascinating, as it combined studying glass production methods with trying to merge function and style in a new and meaningful way. The idea behind the shape of the bottle was to convey a very masculine design (perhaps suitable for a spirits bottle) through the simplified representation of a man’s torso, with broad shoulders and an accentuated neck line. This was a new feature at the time, which had appeared in the bottles of a famous perfume. It gave me enormous satisfaction to win the 1st prize, not so much for the money as for the recognition given to a well-executed design. After winning the prize the bottle went into commercial production, and I have been receiving the royalty payments every year since then: a very pleasant reminder of the Millennium Project competition.


MODULOR

Balz Steiger IED (IT) Millennium Project 1998

I really enjoyed participating in the Millennium Project during my studies at the Istituto Europeo di Design in Milan. The inspiration phase, when I was searching for the right idea, was very intense. During the Millennium Project, I read a book by Le Corbusier in which he described his law of proportions called Modulor, which inspired me to apply his architectural proportions to a product. The shape itself derived from the idea of reflecting the content of the bottle in the bottle itself. The drop of water, a symbol of the purity of liquids, formed by resistance to water and gravity, became the basic shape of my bottle. The neck and the base were formed accordingly, following the Modulor principle of proportion. The bottle became a success for Bruni as well as for myself. Today I am running my own Industrial Design, Branding and Graphic Design studio, in the centre of Zurich.


BACCHIPECTUS

Stephane Froger Les Ateliers (FR) Millennium Project 2000

What are you doing now? I’m the owner of “Le Petit Atelier de Paris”, a small Paris- based studio-workshop. We work on objects made of porcelain and wood for use in everyday life: tableware, accessories, lighting, furniture, jewelry... What is your opinion about Millennium Project? Definitely very positive. Do you think that Millennium Project was helpful for your studies and your future career? Training, communication with your teacher, practical work experience… It was a short but very intense phase of research and creativity. When you’re a student, there are only a few projects that you can follow through to the end. To make an idea materialize is always very beneficial and is a good way to learn. Were the royalties received from your project useful for continuing your studies? Yes they were and continue to be so...


CALIGULA

Juni Salojarvi University of Art and Design Helsinki (FIN) Millennium Project 2003

After a cultural exchange in Melbourne, Australia, I enrolled on a course in Fine Arts, Business & Marketing and graduated with the Master of Arts from UIAH in 2005. At the moment I work as a Concept Designer for Fiskars Oyj, at the Garden EMEA R&D in Helsinki. In addition to my day job, I’ve continued working on design on my own. I have lots of ideas in my head, even outside working hours, you know, in my private life. I got married two years ago, and we now have a small baby: a wonderful, unforgettable experience. In my spare time, I visit art exhibitions, play sports, etc.. It has been fantastic to receive the payment annually, no doubt about it. I have nothing to complain about with the payment calculations: I just trust your figures. I always receive a copy of the sales figures used to calculate the royalties and I’m grateful for that.


PILAR

Minna Mylius University of Art and Design Helsinki (FIN) Millennium Project 2001

My name is Minna Mylius. I graduated in spring 2011 from Aalto University. I’ve recently been working on designing outdoor play equipment and furniture for children. In my work, I believe in usable products, and design focused on the concept of usability. I participated in the Millennium Project competition in 2001, while I was studying at University. I won the first prize in the wine bottle category. That recognition was a great step in my path to be a designer. After the awards ceremony, I got my first job as a designer and I’m still working as a designer today. In the Millennium Project competition I really appreciated the opportunity to meet people from Bruni Glass and hear their opinions about my design. After the competition, they sent me a real bottle created from my design and every year after that I have received royalties. It’s a perfect way to celebrate my achievement year after year.


TIPSY

Nomi Lewin Les Ateliers (FR) Millennium Project 1998

I now have my own business together with Tal Dayan (an industrial designer and my best friend). It’s a design studio and shop in the Flea Market, in Jaffa, Israel. We design products from recycled materials and we have a line called “Local Fairies”, which offers positive ideas for everyday life. We work with rehabilitation centers. Everything in our shop is locally made in Israel, and we also exhibit recycled products by local designers and artists. I am always happy to get news about the royalties every year. Each time it’s a nice surprise. I love the Millennium Project. I think it’s brilliant to give students a chance to design something for the real world, and reward them with royalties... it’s smart to use the creative energy that is out there in the design schools... and it’s a Win-Win situation!


Nicola Schan IED (IT) Millennium Project 1998


Maximilian Bastian University of Art and Design Halle - Burg (D) Millennium Project 2011


Verticality test.


5

POSSIBLE DEFECTS OF A GLASS CONTAINER

POS SIBLE DEFE CTS 1. CLASSIFICATION OF DEFECTS

page 144

2. CLASSIFICATION OF DEFECTS BY MARKET

page 145

This dictionary aims to list as comprehensively as possible the possible DEFECTS OF A GLASS CONTAINER, including:

• diagram and standard name of the defect (often including the most frequently used local terms); • the level of severity of the defect, taking into account the different market sectors in which the container is used.

Defects are rated as: • critical • major + • major • minor or aesthetic

This dictionary should be considered as a worktool and should facilitate the uniform use of terminology by inspectors, whether for routine inspections or audit controls.


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

CLASSIFICATION OF DEFECTS CRITICAL DEFECTS: C DEFINITION: a critical defect is one that - based on judgement and experience - is likely to render the product hazardous or unsafe for the end user. ITEM WITH CRITICAL DEFECT: this is an item with one or more critical defects. It may also have major and/or minor defects.

MAJOR DEFECTS: M+ MDEFINITION: a major defect is a defect which is not critical but may cause failure, or significantly reduce the use of the item for its intended purpose, and may result in: • breakage

of the item during or after filling and packaging; • deterioration of the contents after a certain lapse of time; • risk of work accidents during handling; • impossibility of packing the item; • impossibility of selling the product on the market.

Major defects are further divided into M+ (defects that may cause the container or the equipment to break) and M- (defects that hinder the packaging operations). ITEM WITH MAJOR DEFECT M+ / M-: this is an item that has one or more major defects; it may also have minor defects but no critical ones.

MINOR DEFECTS: m DEFINITION: a minor defect is a defect which does not affect the use of the item for its intended purpose, or one that deviates from established standards which does not significantly affect its use, but which could be considered as undesirable by the customer. ITEM WITH MINOR DEFECTS: this is an item that has one or more minor defects, but no critical or major defects.

144


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

TABLE WINE

SPARKLING WINE

APERITIF

SPIRITS COGNAC

FRUIT SYRUP MILK

BEER CARBONATED

OIL / VINEGAR

CLASSIFICATION OF BOTTLE DEFECTS BY MARKET SECTOR

SPIKE

C

C

C

C

C

C

C

BIRD SWING

C

C

C

C

C

C

C

SPIKE INSIDE THE NECK

C

C

C

C

C

C

C

INTERNAL FRAGMENT OF GLASS, ATTACHED OR LOOSE

C

C

C

C

C

C

C

INTERNAL BLISTERS WITH THIN WALLS

C

C

C

C

C

C

C

FRAGILE ≥ 0.3 MM

C

C

C

C

C

C

C

NOT FRAGILE < 0.3

M+

M+

M+

M+

M+

M+

M+

STUCK WARE

C

C

C

C

C

C

C

BURRS

C

C

C

C

C

C

C

C

C

C

C

C

C

C

M+

M+

M+

M+

M+

M+

M+

BLISTERS ON THE UPPER FINISH

M+

M+

M+

M+

M+

M+

M+

SPLIT

M+

M+

M+

M+

M+

M+

M+

DEFORMATION

M+

M+

M+

M+

M+

M+

M+

CRACKED SEAM

M+

M+

M+

M+

M+

M+

M+

DISCONTINUOUS CRACKS

M+

M+

M+

M+

M+

M+

M+

INCLUSION

M+

M+

M+

M+

M+

M+

M+

MOLD SEAM WITH PINCHED GLASS

M+

M+

M+

M+

M+

M+

M+

UNFILLED FINISH

M+

M+

M+

M+

M+

M+

M+

SPLIT FINISH

M+

M+

M+

M+

M+

M+

M+

IMPACT CONE

M+

M+

M+

M+

M+

M+

M+

INTERNAL MARKS

M+

M+

M+

M+

M+

M+

M+

MISSING OR INCORRECT ENGRAVINGS

M+

M+

M+

M+

M+

M+

M+

EXCESSIVE HOT END SURFACE TREATMENT

M+

M+

M+

M+

M+

M+

M+

EXCESSIVE OR NO COLD END SURFACE TREATMENT

M+

M+

M+

M+

M+

M+

M+

CHOKED NECK

M+

M+

M+

M+

M+

M+

M+

HOLLOW NECK

M+

M+

M+

M+

M+

M+

M+

THIN WALLS

M+

M+

M+

M+

M+

M+

M+

BENT NECK

M+

M+

M+

M+

M+

M+

M+

FLASH AT THE SEAM BETWEEN THE BLOW MOLD AND BOTTOM PLATE

M+

M+

M+

M+

M+

M+

M+

DEFECTIVE ORIENTATION MARKS

M+

M+

M+

M+

M+

M+

M+

DEFECTS CLASSIFICATION

OVERPRESS

FRAGILE

CRIZZLED FINISH

LEGEND:

NOT FRAGILE

CRITICAL = C

MAJOR + = M+

MAJOR - = M-

MINOR = m

145


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

TABLE WINE

SPARKLING WINE

APERITIF

SPIRITS COGNAC

FRUIT SYRUP MILK

BEER CARBONATED

OIL / VINEGAR

CLASSIFICATION OF BOTTLE DEFECTS BY MARKET SECTOR

C

C

C

C

C

C

C

NOT SHARP

M+

M+

M+

M+

M+

M+

M+

CRACKED

M+

M+

M+

M+

M+

M+

M+

NOT CRACKED ≥ 4 MM

M-

M+

M-

M-

M-

M-

M-

NOT CRACKED < 4 MM

m

M-

m

m

m

m

m

SPHERICAL > 4 MM

M-

M+

M-

M-

M-

M-

M-

ON THE TOP

M+

M+

M+

M+

M+

M+

M+

ON THE BARTOP

M-

M-

M-

M-

M-

M-

M-

ON THE ITEM

M+

M+

M+

M+

M+

M+

M+

ON HORIZONTAL FINISH

M+

M+

M+

M+

M+

M+

M+

ON THE THREAD ON THE FINISH

M-

M-

M-

M-

M+

M-

CRIZZLES IN THE GLASS WITH RADIAL

M+

M+

M+

M+

M+

M+

M+

m

M-

M-

M-

m

m

m

≥ 3 MM

M+

M+

M+

M+

M+

M+

M+

< 3 MM

m

m

m

m

m

m

m

SCREW FINISH

M+

M+

M+

M+

M+

M+

M+

CORK FINISH

M+

M+

M+

M+

M+

M+

M+

DEFECTS CLASSIFICATION

STUCK GLASS ON THE EXTERNAL SURFACE

BLISTERS ON THE EXTERNAL SURFACE

CHIPPED FINISH

CHECKS ON THE FINISH

DIFFERENT DROP OF GLASS

LUMP OFFSET FINISH ≥ 0,3 MM

SHARP

ON THE EXTERNAL SURFACE WITHOUT CRIZZLES

SHOULDER CHECK

M+

M+

M+

M+

M+

M+

M+

CAPACITY

M+

M+

M+

M+

M+

M+

M+

APPEARANCE

M-

M-

M-

M-

M-

M-

M-

LIGHT

M+

M+

M+

M+

M+

M+

M+

HEAVY

m

m

m

m

m

m

m

UNEVEN

m

m

m

m

m

m

m

HEEL TAP

m

m

m

m

m

m

m

BAFFLE MARK

M-

M+

M-

M-

M-

M+

M-

OUT OF THE ROUND ITEM

M-

M+

M+

M+

M-

M-

M-

DEFORMED ITEM

M-

M+

M+

M+

M-

M-

M-

OUT OF THE VERTICAL FINISH

M-

M+

M+

M-

M-

M+

M-

BULGED FINISH

M-

M-

M-

M-

M-

m

M-

LIGHT SPOTS

M-

M-

M-

M-

m

m

m

LUMP INSIDE NECK

M-

M-

M-

M-

m

m

m

CHIP

M-

M-

M-

M-

M-

M-

M-

SUNKEN OR DEFORMED PUNT

IRREGULAR GLASS DISTRIBUTION ON THE BOTTOM

LEGEND:

146

CRITICAL = C

MAJOR + = M+

MAJOR - = M-

MINOR = m


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

TABLE WINE

SPARKLING WINE

APERITIF

SPIRITS COGNAC

FRUIT SYRUP MILK

BEER CARBONATED

OIL / VINEGAR

CLASSIFICATION OF BOTTLE DEFECTS BY MARKET SECTOR

BODY

M-

M-

m

m

m

m

m

BOTTOM

m

M-

m

M-

m

m

m

NECK

m

m

m

m

m

m

m

BOTTOM

DEFECTS CLASSIFICATION

OPEN MARK SHEAR MARKS (NOT)

m

m

m

m

m

m

m

CHECKS UNDER FINISH

m

M+

m

m

m

m

m

SHIFTED BOTTOM PLATE

M-

M-

M-

M-

M-

M-

M-

INCLINED BOTTOM PLATE

M-

M-

M-

M-

M-

M-

M-

DEFORMED BOTTOM

M-

M-

M-

M-

M-

M-

M-

BENT FINISH

M+

M-

M-

M+

M-

M-

M+

DIRT ON OUTSIDE SURFACE

M-

M-

M-

M-

M-

M-

M-

HAMMERED APPEARANCE

m

m

m

m

m

m

m

TEAR

M-

M-

m

M-

m

m

m

CORD

m

m

M-

M-

m

m

m

MOLD SEAM

m

m

m

m

m

m

m

RUINED BAFFLE

m

m

m

m

m

m

m

FOLDS

m

m

m

m

m

m

m

WASHBOARD MARKS

m

m

m

m

m

m

m

BRUSH MARKS

m

m

m

m

m

m

m

ORANGE PEEL MARKS

m

m

m

m

m

m

m

TOAD SKIN MARKS

m

m

m

m

m

m

m

SEEDS

m

m

m

m

m

m

m

FIRE CRACKS

m

m

m

m

m

m

m

CHAIN MARKS

m

m

m

m

m

m

m

CRIZZLED BOTTOM

m

m

m

m

m

m

m

CRACKED BOTTOM

m

m

m

m

m

m

m

METROLOGICAL SIGNS

M-

M-

M-

M-

M-

M-

M-

LOGO OR MARKETING

m

m

m

m

m

m

m

m

m

m

m

m

m

m

M+

M+

M+

M+

M+

M+

M+

m

m

m

m

m

m

m

M+

M+

M+

M+

M+

M+

M+

WITHOUT

m

m

m

m

m

m

m

EXTERNAL

m

m

m

m

m

m

m

BAD ENGRAVINGS OIL MARKS

FOR BIDULE OR POURER

HOLLOW FINISH OR NECK INTERNAL

OTHER NECKS

DIRTY NECK

LEGEND:

CRITICAL = C

FOR BIDULE OR POURER

MAJOR + = M+

MAJOR - = M-

MINOR = m

147


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

TABLE WINE

SPARKLING WINE

APERITIF

SPIRITS COGNAC

FRUIT SYRUP MILK

BEER CARBONATED

OIL / VINEGAR

CLASSIFICATION OF BOTTLE DEFECTS BY MARKET SECTOR

CROWN CAP

M+

M+

M+

M+

M+

M+

M+

FOR BIDULE OR POURER

m

m

m

m

m

m

m

DOUBLE MOLD SEAM OR PARISON ROTATION MARK

m

m

m

m

m

m

m

LOADING MARKS

m

m

m

m

m

m

m

CORK

M-

M-

SCREW

m

m

m

m

m

UNDER PRESSURE

m

M-

m

M-

m

m

OPERCULUM

M-

M-

M-

M-

DEFECTS CLASSIFICATION

BULGED OR UNFILLED FINISH

FOLDS INSIDE THE FINISH

M-

M-

BIDULE

M-

POURER CORK

GLASS TRIMMING ON EXTERNAL FINISH

m

SCREW

M+

UNDER PRESSURE

M-

m

UNDER PRESSURE

HIGH FINISH SEAM

M+

UNDER PRESSURE

OUT OF ROUND FINISH

148

M+

M+

M-

M-

M+

M-

M-

m

M-

M-

M-

M-

M-

M-

OTHER NECKS

m

m

m

m

m

m

m

OTHER NECKS

M-

M-

SCREW

M-

M-

M-

M-

M-

CROWN CAP

M-

M-

M-

M-

M-

M-

SKIRT

m

m

m

m

m

m

m M-

m

m

m

CORK

m

m

m

SCREW

M-

M-

m

m

M-

m

CROWN CAP

M-

M-

m

m

M-

m

SKIRT

m

m

m

m

m

m

CORK

m

m

m

SCREW

M-

M-

M-

M+

M-

UNDER PRESSURE

M-

M-

M-

M+

M-

FOR BIDULE OR POURER

CRITICAL = C

M+

M-

OTHER NECKS

LEGEND:

M+

M-

MMm

POURER

ROLLED IN FINISH

M-

USING LIDS OR CHAMPAGNE CORK

POURER

FOLDS ON THE FINISH

Mm

M+

POURER

SEAM UNDER FINISH

m

MAJOR + = M+

m

M-

M+

M+

M+

M+

M+

M+

M+

m

m

m

m

m

m

m

MAJOR - = M-

MINOR = m


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

SPIKE A projection of glass extending upwards from the bottom on the inside of the jar or bottle. More frequent in the “press-blow” process, and in containers with a broad mouth.

BIRD SWING A bird swing can occur both in the “press-blow” and “blow-blow” process. It is a thin strand of glass across the inside of a container either between the walls or between the wall and the bottom.

SPIKE INSIDE THE NECK Blow-blow process: small projection of glass at the finish. Press-blow process: irregular wall thickness with a crater-like depression in the centre, whose edges are in relief and can chip easily.

Welded seam Glass bit

affixed spike

INTERNAL FRAGMENT OF GLASS, ATTACHED OR LOOSE Fragment of glass of any size, attached or loose, inside the container.

INTERNAL BLISTERS WITH THIN WALLS Air bubbles trapped inside the glass mass to be found on the internal surface. These blisters are usually elongated and can be: cracked > the surface is broken; not cracked > with a thin skin.

149


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

OVERPRESS A finish which has excessive glass projecting upward from the inside edge of the finish. This is a critical defect in all types of finish. Fragile (C) Not fragile (M+) Problem • Defective closure, risk of leaks, product deterioration (M+). • Breakage of the overpress with risk of contamination (C).

STUCK WARE Two articles are attached while hot and separated while cold. This separation causes a sharp or cutting edge (rough glass edges on the side, lacerations on the contact area between the bottles). Problem • Impossible to pack the item correctly. • Risk of injury to the worker or the end user.

BURRS Sharp edges along the lines of the mold seams Problem • Impossible to pack the item correctly (M+). • Risk of injury to the worker or the end user.

CRIZZLED FINISH Some or many fine surface fractures on the top of the finish (mouth). Fragile (C) Not fragile (M+) Problem • Defective closure: risk of leaks. Not dangerous with corks (M+). • Risk of contamination (C).

150


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

BLISTERS ON THE UPPER FINISH Broken or unbroken bubbles in the thickness of the glass on the finish. Problem • Risk of glass particles inside. • Risk of breakage during the heat treatment and sealing. • Defective closure, risk of leaks, product deterioration.

SPLIT This is a crack which passes through the whole thickness of the glass (in any part of the article). Problem • Breakage of the article during or after filling and packing. • Risk of accidents due to bursting if used with a carbonated product.

DEFORMATION Article is malformed, warped or completely sunken. Problem • Impossible to pack the item properly.

CRACKED SEAM A fracture which usually occurs in the body of the article. It doesn’t always cause the breakage of the articles. Problem • Breaking of the article before, during or after its packaging.

151


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

DISCONTINUOUS CRACKS Discontinuous surface cracks with one or more shiny parts (straighter crack: no protruding glass can be felt). Problem • Breakage of the article during or after filling and packing (bursting on handling in workplace when used for carbonated products or sparkling wine).

INCLUSION Foreign body in the glass. Problem • Severe risk of breakage during or after packing operations (impacts), especially with sparkling products.

MOLD SEAM WITH PINCHED GLASS When the finishing mold closes it blocks the structure and produces a heavy seam. Problem • The item cannot be properly packed.

UNFILLED FINISH The finish is not completely regular; the thread profile has not been formed properly. There is glass missing from the top surface. Problem • Defective sealing: risk of leaks, product deterioration, problems in vacuum filling. • Sometimes this can be just a minor defect (m), for instance unfilled finish on the bead of a cork mouth.

152

in the top under the thread

in the bead

in the thread


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

SPLIT FINISH A small vertical crack starting at the top of the finish and going downwards. This defect is difficult to detect because it does not reflect light. Problem • Risk of breakage during filling and packaging, leaking of product.

IMPACT CONE Impact point from a knock that extends into the glass mass in a cone shape.

impact

Problem • The article is not suitable for filling (serious risk of breakage).

INTERNAL MARKS Internal marks of any kind (water, dust, cardboard, grease etc.) which cannot be removed by the preliminary washing procedure. Problem • Item not suitable for filling and packing.

MISSING OR INCORRECT ENGRAVINGS Any missing or incorrect engravings meaning that it is not possible to sell the article (capacity indication, spelling mistakes, etc.).

153


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

EXCESSIVE HOT END SURFACE TREATMENT • Tin:

visible iridescence on the empty article, more obvious when filled. • Titanium: barely visible or invisible mark on empty article, it gives the product a dark/purplish color (DE). For further information see chart on page 145 and page 178 section 1.3.

EXCESSIVE OR NO COLD END SURFACE TREATMENT • Excessive:

extremely slippery bottles on the filling line with possible label detachment. • No treatment: friction on contact between containers (scratching of bottles during transport or packing). For more information see page 145 and page 178 section 1.3.

CHOKED NECK • Excess

of glass in the neck which partially or completely obstructs the bore and doesn’t allow the filling tube to be introduced.

Problem container is not suitable for use, risk of breakage during filling, deterioration of contents.

• The

HOLLOW NECK Depression in the thickness of the glass in the neck of a bottle. Problem • Fragility depending on the thickness of the residual glass.

154


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

THIN WALLS The thickness of the glass does not meet the specifications. Problem • Risk of breakage if knocked during transport or packing.

BENT NECK The vertical axis of the neck is at an angle to the vertical axis of the body. Problem • Difficult to fill and/or seal.

FLASH AT THE SEAM BETWEEN THE BLOW MOLD AND BOTTOM PLATE A projection of glass > 0.5 mm that runs around the seam between the finishing mold and bottom plate, due to incorrect join between the mold and the bottom plate leading to protruding glass. Problem • Poor resistance to knocks and thermal shocks.

DEFECTIVE ORIENTATION MARKS The marks do not conform to the drawing or are missing. Problem • Hinders correct decoration and/or labelling.

155


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

STUCK GLASS ON THE EXTERNAL SURFACE Unwanted pieces of glass, which may or may not be sharp, stuck to the external surface of the item. (M+) not sharp (C) sharp Problem • It may affect filling and packing.

BLISTERS ON THE EXTERNAL SURFACE Usually elongated, they may be: Cracked (C) > the outer surface is broken Not Cracked > but with a thin skin, the severity level is: > 4 mm (M+) = 4 mm (M-) < 4 mm (m) Problem • Cracked problem: potentially hazardous for the operator. • Not Cracked: ≥ 4 mm > risk of breakage during bottling and handling. Dangerous with carbonated beverages. < 4 mm > not very dangerous, considered mainly an aesthetic defect.

CHIPPED FINISH A small fragment of glass has been chipped off the finish (scratched), sometimes not completely detached.

ON THE TOP (M+) ON THE SIDE (M-)

Problem • On the top: problems for vacuum filling, bad sealing, risk of leakage and deterioration of the product. • On the side: risk of breakage during use.

156


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

CHECKS ON THE FINISH HORIZONTAL (M+) - THREADS (M+ / M-) Small crack running from the top of the finish in a downward direction. It can be seen by looking at the light reflection while turning the bottle. Problem • Risk of breakage during packing (corking, sealing).

DIFFERENT DROP OF GLASS • On the glass mass with radial crizzles (M+). • On the external surface or the glass mass without crizzles (M-). Problem the case of radial crizzles on the glass mass, risk of breakage during filling. • On the external surface or in the glass mass without crizzles: not very dangerous, risk of breakage caused by thermal shocks, aesthetic appearance of glass. • In

LUMP Small glass protuberance on top surface of the finish, only in one point of the finish: ≥ 0.3 mm (M+) < 0.3 mm (m). Problem • ≥ 0.3 mm > defective sealing: leakage risk, product deterioration with crown or screw caps, risk of breakage on wired corking. • < 0.3 mm > not very dangerous.

OFFSET FINISH ≥ 0.3 MM When the offset is up to or more than 0.3 mm. Problem • Screw Pressure closure: bad sealing, risk of leakage. • Cork closure: risk of breakage during corking.

157


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

SHOULDER CHECK Beginning of a crack that does not pass through the entire thickness of the glass (usually in a straight line). Problem â&#x20AC;˘ Breakage of the article during or after filling and packaging.

SUNKEN OR DEFORMED PUNT Slough or deformation of the glass in the punt, more or less serious. (M-) Slough or deformation of glass in the punt, thus making the bottle below capacity. (M+)

IRREGULAR GLASS DISTRIBUTION ON THE BOTTOM Too little or too much glass on the bottom.

TOO THIN >>

TOO THICK >>

158


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

WAVY >>

HEELTAP >>

BAFFLE MARK Imprint on the bottom due to poor fit between the baffle plate and the blank mold. Problem • The stability of the item, its resistance to heat treatments and the internal pressure resistance may be compromised.

OUT OF ROUND ITEM The article is misshapen or the circumference is imperfectly round. Problem • Labeling can be difficult, capacity problems may arise.

Flat on seam

159


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

DEFORMED ITEM An item that, while corresponding to the shape in the technical drawing, has anomalies in the shape that may cause problems during filling and packing (sunken shoulder, misshapen body, etc.). Problem • Depending on its severity, this defect may affect the filling, labeling, capacity, etc..

OUT OF VERTICAL FINISH The finish axis is not aligned with the body, even though the finish and body axes are parallel and vertical. Problem • Depending on the defect severity, sealing may be affected. Bad grip with screw and champenoise (wired cork) finishes. Trigger or breaking of the closure bridges.

BULGED FINISH Protuberance on the inside of the finish which can affect the finish during uncorking; no risk of scratching. Problem • Depending on the severity, it may affect the corking (bidule, for example) or the filling level.

LIGHT SPOTS A markedly thinner area in the thickness of the glass which may cause fragility in the bottle. Problem • Aesthetic problem, poor appearance, low risk of breakage.

160


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

LUMP INSIDE NECK Round protuberance inside the neck, not fragile. Problem â&#x20AC;˘ Problems may arise with corking.

BUTTERFLY WING CHIP An impact point on the body of the item (generally on the shoulder or near the bottom), usually surrounded by concentric circles giving it a scaly look (similar to a butterfly wing) and leaving the glass wall weakened.

SHELL SHAPED CHIP An impact point on the body of the item (generally on the shoulder or near the bottom), usually surrounded by concentric circles giving it a scaly look (similar to a shell) and leaving the glass wall weakened.

OPEN MARK Superficial and external mark with two separated, irregular rims. It can be situated on the bottom, and is normally not visible. Body (M- / m) Bottom (m)

161


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

SHEAR MARKS (NOT) A mark on the surface of the bottle caused by the shears. Problem • Aesthetic problem.

CHECKS UNDER FINISH A surface crack under the finish, at the join between the finish mold and the preparatory mold. Problem • Risk of breakage with carbonated or sparkling beverages and a wired cork.

SHIFTED BOTTOM PLATE The whole body of the article has shifted at one side by ≥ 1 mm, the bottom axis is not aligned with the body axis. Problem • Risk of scratching, not over 0.5 mm for decorated items.

INCLINED BOTTOM PLATE The bottom is not completely perpendicular to the axis of the bottle. It may be inclined to one side or wavy. Problem • Instability of the item.

162


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

DEFORMED BOTTOM The center of the bottom is lower than the external rim of the bottom. Problem • Instability of the item.

BENT FINISH The vertical axis of the finish is at an angle to the vertical axis of body. Problem • Serious defect in screw, crown and twist off finishes, less important in cork finishes.

DIRT ON OUTSIDE SURFACE Article has dirt deposits on the external surface (for example oil marks), or a rough or scaly appearance, on the shoulder or on the body. Problem • Not suitable for use for aesthetic reasons.

HAMMERED APPEARANCE Irregular external surface. The body looks rough and wavy, with fine undulations. Problem • Aesthetic defect, the item is not suitable for luxury products.

163


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

TEAR An open mark/crack on the glass surface.

CORD A thread of a different type of glass in the mass (a thin glass ripple that can be seen through the glass). Problem • An aesthetic defect, more serious for items to be frosted.

MOLD SEAM A thin ridge of glass along the parting line, caused by the mold joint. Problem • Labeling problems.

RUINED BAFFLE Excess of glass (flash) appearing whitish in color (like crushed glass), situated on the baffle line.

164


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

FOLDS Almost horizontal concavities on the outer surface of the item; shallow, open wrinkles.

WASHBOARD MARKS Fine horizontal ripples on the glass surface.

BRUSH MARKS Numerous fine vertical marks, often on the shoulder.

ORANGE PEEL MARKS Rough, bumpy surface that resembles the texture of an orange.

165


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

TOAD SKIN MARKS Glass is regularly distributed, but the exterior is not smooth (covered with small plates) and it is characterized by a grainy and dirty aspect, similar to the skin of a toad.

SEEDS Very small gas bubbles in the glass mass, < 0.8 mm.

FIRE CRACKS A discontinuous, open surface crack, dull in appearance, caused by local changes in temperature. Unlike a split, it is an open crack and can be felt when touching the bottle.

CHAIN MARKS Marks on the bottom of the bottle caused by contact with the conveyor belt immediately after manufacture.

166


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

CRIZZLED BOTTOM Small axial grooves grouped around the baffle line.

CRACKED BOTTOM Web-shaped cracks.

BAD ENGRAVINGS The engravings on the glass are difficult to read to a greater or lesser extent.

OIL MARKS String of grey bubbles inside the glass.

167


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

HOLLOW FINISH OR NECK Depression in the thickness of the glass in the finish or neck. Problem • The correct application of a pourer is not possible with screw finishes. Sealing problems with short synthetic corks.

DIRTY NECK Black spots (grainy aspect).

BULGED OR UNFILLED FINISH The profile of the finish is not symmetrical. • Double

mold seam or parison rotation mark. At the mold seam point, the vertical line is double instead of single, which may be more or less visible, mainly near the bottle shoulder • Loading marks Small parallel horizontal marks normally on the bottle body.

FOLDS INSIDE THE FINISH Vertical marks inside the finish. Problem • Defective corking: risk of leakage.

168


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

GLASS TRIMMING ON EXTERNAL FINISH Protruding ridge of glass around the upper part of the finish (thin rim of glass) > 0.2 mm. Problem • Defective corking: risk of glass inside the bottle during recorking.

SEAM UNDER FINISH A seam ≥ 0.5 mm, situated on the joint between the finishing mold ring and the blank molds.

HIGH FINISH SEAM A seam of glass ≥ 0.2 mm, on the joint between the two sections of the neck ring mold.

FOLDS ON THE FINISH Vertical or horizontal external marks on the finish, purely an aesthetic defect.

169


5. POSSIBLE DEFECTS OF A GLASS CONTAINER

OUT OF ROUND FINISH The finish is not round.

ROLLED IN FINISH Entry slough or extra thickness of the glass inside the finish. Problem • Defective corking.

170


4. I POSSIBILI DIFETTI DI UN CONTENITORE

A Bruni Glass technician takes a resin prototype from the 3D printer.


4. I POSSIBILI DIFETTI DI UN CONTENITORE


4. I POSSIBILI DIFETTI DI UN CONTENITORE Bruni Glass technicians and designers at work.


ANNOTAZIONI

Control of internal finish.

174


6

QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

SUPPLY SPECIFICATIONS FOR FOOD BOTTLES AND JARS. FOOD - OIL - SPIRITS 1. GENERAL CONDITIONS

page 176

2. GENERAL CHARACTERISTICS

page 178

3. DEFINITION OF DEFECTS

page 183

4. STATISTICAL INSPECTION

page 184

5. SPECIAL INSPECTIONS

page 188

6. TOLERANCES (IN ACCORDANCE WITH ISO/DIS 9058/2)

page 190

7. REGULATIONS ISO/UNI 2859

page 192

8. ISO/UNI 2859/1 EXCERPT TABLES

page 210

QUA LITY


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

GENERAL CONDITIONS

1. DEFINITION

These specifications establish the quality parameters of the supply agreement/contract with the aim of facilitating the Customer-Supplier relationship. For each type of defect, they set out the minimum levels of quality that are acceptable to the Customer together with the control methods the Supplier needs to carry out in order to guarantee them.

2. CONTAINER DESCRIPTION

Specifically, these specifications define the minimum quality levels for defects that are acceptable to the Customer, with reference to bottles and jars for food use.

3. RESPONSIBILITIES

176

Where there is clear evidence of defects, Bruni Glass will replace, at its own expense, any consignment that is found defective in accordance with these specifications and following the procedures specified in point 4 below. Bruni Glass will despatch the goods within 7 days (if in stock) or with the least possible delay if a new product is necessary, and in any case within a maximum of 60 days from the validation of the complaint (except in very exceptional cases where a new glass/color production cycle is required). However, the supplier has the option to use the defective products on agreement with the Customer, paying them the additional cost for the percentage of scrap that exceeds the limits stated in these specifications. Clearly, when a claim is submitted it is in both partiesâ&#x20AC;&#x2122; interests to plan and agree on the most efficient, rapid and cost-effective solution in a spirit of reciprocal cooperation. Bruni Glass deems that an incoming control is an essential prerequisite for the acceptance of a batch and will not, in any case, accept any responsibility for damage caused by breakages, scrap, or losses in production, products and accessories (caps, labels, etc.) that have occurred on the Customerâ&#x20AC;&#x2122;s production line. Bruni Glass and the Customer may also agree on different A.Q.L. (Acceptance Quality Levels), in the case of formats that cause particular production problems.


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

3.1 CLEANING

While the Supplier is committed to preventing any risk of contamination during the production and storage phases, it is entirely the filler’s responsibility to ensure the hygiene of the product before using it (Law. 155/97).

4. AUDIT

The two parties may agree on a mutual Audit procedure: • Customer

audit of the Bruni Glass Quality System. • A Bruni Glass audit at the Customer’s plant, if it is necessary, in order to find out the methods of use and consequent characteristics required by the products concerned.

5. VALIDITY/ACCEPTANCE

This agreement, signed by both parties - the Customer and Bruni Glass shall be deemed to be tacitly renewed without any time limit. Any amendment to this agreement must be approved by both Parties.

177


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

GENERAL CHARACTERISTICS

1. CHEMICAL AND PHYSICAL CHARACTERISTICS

1.1 GENERAL REQUIREMENTS

The containers for food use should comply with current EU regulations: • EC

Reg. No. 1935/2004 - on materials and objects destined to come into contact with food products • EC Reg. No. 2023/2006 - on good production practices for materials and objects destined to come into contact with food products • Pres. Decree 777/82 and subs. Amendments and updates • Minis. Decree 21/03/1973 and subs. Amendments and updates • Law Decree No. 152 dated 3 April 2006 art. 226 (environmental regulations).

1.2 MATERIALS

Items are produced with soda-lime glass Class III (unless otherwise specified).

1.3 SPECIAL TREATMENT

Where applicable, this consists of a treatment with tin or titanium tri-chloride (hot treatment) or with oleic acid or polyethylene (cold treatment).

1.4 LIGHT TRANSMISSION

178

This varies according to the color and thickness of the glass; the table below shows the approximate values of glass filtering power: COLOR OF GLASS

SAMPLE THICKNESS

FILTERING POWER

FLINT

5 mm

12%

HALF GREEN

3 mm

16%

BLUE

3 mm

18 +/- 5%

UVA GREEN

3 mm

87%

ANTIQUE GREEN

3 mm

99%

OAK GREEN

3 mm

64%

AMBER

3 mm

> 99%

EMERALD

3 mm

45 +/- 5%

YELLOW

3 mm

99.5%

GOLD

3 mm

60%


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

1.5 ANNEALING

The containers are judged to be properly “annealed” when the deformation does not exceed 4 standard deforming disks.

2. TECHNICAL DRAWING

The Supply specifications shall include the Technical Drawings for the items concerned, approved by the Customer. Any change in the dimensions, either required by the Customer or proposed by Bruni Glass, will entail the issue of a new Technical Drawing, which, on approval by the Customer, shall replace the earlier drawing.

The Technical Drawing shall include the following indications: • code

number dimensional values • nominal filling level • brim capacity • date and approval signature • overall

The Nonconformity of the Article in just one of the Dimensional Values given with tolerance limits, will be deemed a Major Defect.

3. PACKAGING

The Supply specifications shall be accompanied by the Packaging Sheet indicating the details of the packaging and palletization. In particular, the following information shall be provided: • code

number description • type of pallet • total number of units per pallet • total number of units per layer • number of layers • packaging material used (e.g. plastic or cardboard separators) • item

4. PALLET LABEL

Labels providing the necessary identification data regarding the packaged product shall be affixed to each pallet, indicating the: • item

code and/or description

179


5. IL CAPITOLATO DI QUALITÀ (TERMINOLOGIA, DEFINIZIONI, METODI)

180


5. IL CAPITOLATO DI QUALITÀ (TERMINOLOGIA, DEFINIZIONI, METODI)

A Bruni Glass Quality Dept. technician carries out a test on closing systems.

181


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

• number

of pieces per pallet number of pallets • date of production • place of production • progressive

5. BOUNDARY SAMPLES

A boundary sample is a container which has aesthetic defects to a degree that constitutes the maximum acceptable limit. The collection of boundary samples represents the “Complete set” of defects. Generally, and for private containers in particular, the “Complete set” will be established in the presence of the Customer for the first production or sampling and will be considered to be the aesthetic benchmark for future production.

6. DEFINITION OF BATCH

182

Glass production is a continuous production cycle, therefore a Production Batch is represented by the total production campaign of the same item, which may last one or more days. During the Delivery phase the “Batch” is represented by the quantity corresponding to a delivery independently of the quantity of the production itself.


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

DEFINITION OF DEFECTS

1. DEFECTS CLASSIFICATION

Defects are grouped into three classes, according to their severity: • critical defects: defects that may cause physical injury to the consumer of the product; • major defects: defects that may prevent the container from being used or cause a deterioration of the product; • minor defects: defects of an aesthetic nature that do not affect the functionality of the container or the packaging process for the article. CRITICAL DEFECTS (ACCEPTANCE QUALITY LEVEL) A.Q.L. = 0.065 BIRDCAGE/SWING SPIKE, HOT PLUG, STUCK PLUG (INTERNAL) OVERPRESS ON THE FINISH, THAT MAY BREAK STUCK OR LOOSE GLASS INSIDE INTERNAL DIRT NOT RELATED TO MANUFACTURING

INSPECTION LEVEL II • • • • •

MAJOR DEFECTS (ACCEPTANCE QUALITY LEVEL) A.Q.L. =

2.5

DIMENSION OUT OF TOLERANCE CAPACITY OUT OF TOLERANCE SEAM ON TOP OR SIDE OF FINISH MALFORMED FINISH SERIOUS DEFORMATIONS THIN GLASS DISTRIBUTION AFFECTING STRENGTH BODY CHECKS SHOULDER AND NECK CHECKS BROKEN OR STRETCHED BLISTERS ON THE FINISH >2 MM

INSPECTION LEVEL II • • • • • • • • •

MINOR DEFECTS (ACCEPTANCE QUALITY LEVEL) A.Q.L. = 6.5 WASHBOARDS EXTERNAL DIRT IMPACT MARK PROMINENT MOLD JOINT STONES > 2 MM AIR BUBBLES > 2 MM COLOR ORANGE PEEL IRREGULAR DISTRIBUTION OF GLASS

INSPECTION LEVEL II • • • • • • • • •

N.B.: Control level II is the average level of standard sampling indicated in Military Standard 105 E, which also indicates Levels I (less restrictive) and III (more restrictive).

183


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

STATISTICAL INSPECTION

1. SAMPLING ACCEPTANCE

The sample used for the acceptance controls should be representative of the whole batch. A random selection of the sample will be carried out at various points of the supply in order to respect the uniformity of the batch following the table below: SAMPLING TABLE NO. OF PACKS PER BATCH 0 - 25 26 - 36 37 - 49 50 - 64 65 - 81 82 - 100 NO. > 100

NO. OF PACKS TO BE INSPECTED 5 6 7 8 9 10 (N)1/2

Damaged pallets should not be part of the statistical sampling, but should be put aside and sampled separately.

The sample size and the criteria to be followed for acceptance or refusal of the batch are those described in Military Standard 105 E:

Level II General Inspection for normal inspections (Table 1).

BATCH SIZE PCS 3,201 - 10,000 10,001 - 35,000 35,001 - 150,000 150,001 - 500,000 > 500,000

TABLE 1: LEVEL II GENERAL INSPECTION A.Q.L. (*) SAMPLING SIZE A.Q.L. 2.5 0.065 PCS A (째) R (째) A R 200 0 1 10 11 315 0 1 14 15 500 1 2 21 22 800 1 2 21 22 1,250 2 3 21 22

(*) A.Q.L.: acceptance quality level (째) A: accepted / R: refused

184

A.Q.L. 6.5 A 21 21 21 21 21

R 22 22 22 22 22


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

2. INSPECTION PROCEDURES FOR ACCEPTANCE

Once the sampling has been carried out in accordance with Table 1, the container defects are identified and classified according to the categories described. If a container exhibits several defects, only the highest category of defect will be considered for the purposes of the sampling. A batch must be accepted if, during the incoming supply inspection, the number of defective containers is below the established acceptance limit.

If the number of defects exceeds the established limit, the batch will not be accepted. The samples of the defective products should be returned along with all the information necessary for dealing with the complaint as described in point 4.

Bruni Glass reserves the right to carry out a second inspection. If the batch is rejected, Bruni Glass undertakes to send a replacement of the products to the Customer. In exceptional cases, the Customer may make a fresh selection of goods, subject to prior arrangement and agreement on procedures and costs.

3. DEFECTS DISCOVERED DURING PRODUCTION

In the event of repeated production line accidents which may indicate that the established A.Q.L.s have been exceeded, a statistical inspection shall be carried out on the remaining containers to verify if the batch quality complies with the Supply Specifications. If a batch that has passed the acceptance inspections subsequently reveals a defect on use that may be traced to a clearly defined phase of the production period (for instance a pallet or a shift), the articles concerned in that phase (the pallet or the shift) shall undergo a special inspection and shall subsequently be refused if the A.Q.L. established in the specifications have been exceeded. In the event of a claim, Bruni Glass will withdraw the goods and replace them.

Complaints will only be considered if accompanied by all the necessary identification details for the batch concerned.

4. COMPLAINTS

The Customer should inform Bruni Glass of any defects that have been discovered by submitting a complaint which is defined here as a claim. The Complaint Form should be submitted to Bruni Glass in writing and the samples considered defective should be sent as soon as possible, together with the identification details of the pallet (item code, batch and production date, number of pallets, percentage of defective items). Complaints will only be accepted if accompanied by all the required data.

185


5. IL CAPITOLATO DI QUALITÀ (TERMINOLOGIA, DEFINIZIONI, METODI)

Testing the glass thickness.

186


Quality control on a new jar.

Testing the vacuum seal created above.


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

SPECIAL INSPECTIONS

1. TECHNOLOGICAL TESTS

1.1 AXIAL LOAD RESISTANCE

The Axial Load Resistance is determined by means of the Vertical Load Tester by applying an increasing stress onto the top of the container finish until it breaks.

188

The Axial Load Resistance limits are defined by Bruni Glass according to the type of item and are inspected following the methods indicated in UNI Standard 9035 (ISO 8113). Non-compliance with such limits constitutes a Major Defect.

1.2 IMPACT TEST

The Impact Test (inch/pounds) is carried out by monitoring the container breakage caused by the impact with an oscillating hammer with a given mass positioned at a given height. The measurement can be made either at the height of the shoulder or at the bottom of the container.

The Impact Test Limits are defined by Bruni Glass according to the type of item and are tested using the methods described in UNI Standard 9302.

Non-compliance with these limits constitutes a Major Defect.

1.3 THERMAL SHOCK

The resistance to the so-called “Thermal Shock” is evaluated in accordance with international regulations.

The equipment used is composed of two basins containing water at a determined and constant temperature: one is at room temperature (about 20°C), the other is at a higher temperature (about 65°C).

The containers are immersed for 15 minutes in the water at the higher temperature and then in the water at room temperature for two minutes. According to ASTM regulations, a resistance to 40°C or 113°F is considered acceptable.


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

1.4 RESISTANCE TO INTERNAL PRESSURE

Each glass container has its own pressure resistance which depends on its shape, weight and the type of application for which it is intended. The pressure resistance test is carried out using the standardized methods and equipment indicated in UNI 7458 table (ISO 7458).

2. FUNCTIONAL TESTS

2.1 CAPACITY

The total brimful capacity is measured using the gravimetric method by calculating the difference in weight between two containers of the same type, one filled with distilled water at a temperature of 20째C, and an empty one. The value obtained represents the capacity of the container expressed in millilitres (ml). (See also page 190).

2.2 OVALITY

The Ovality is the difference between the maximum and minimum diameters of the body and it is measured using a precision tool calibrated to a hundredth of a millimetre. (See also page 190).

2.3 VERTICALITY

The verticality is checked using an instrument consisting of a table with a reference dihedral measure and a rod with a comparator.

The glass container is placed on the table next to the dihedral measure. The verticality is given by the difference of the half-distance between the top of the product and a fixed point on the gauge. This is measured after the product has completely rotated on itself, according to the table in ISO 9008 (UNI 29008). (See also page 191).

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6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

TOLERANCES (IN ACCORDANCE WITH ISO/DIS 9058/2)

1. TOLERANCE FOR BRIMFUL CAPACITY

The tolerance for brimful capacity must comply with the standards indicated in the following Table 1. TOLERANCE FOR BRIMFUL CAPACITY NOMINAL CAPACITY ML from

% OF NOMINAL CAPACITY

50 to 100

from 100 to 200

±3 ±3

from 200 to 300 from 300 to 500

±6 ±2

from 500 to 1000 from 1000 to 5000

± 10 ±1

2. TOLERANCE FOR NOMINAL HEIGHT

The tolerance for nominal height, calculated in mm, should be calculated using the following formula:

TH = ± (0.6 + 0.004 H)

where H is the nominal height of the product in mm.

3. TOLERANCES FOR MAXIMUM NOMINAL DIAMETER OF THE BODY

The tolerance for the maximum nominal diameter of the body in mm should be calculated using the following formula:

TD = ± (0.5 + 0.012 D)

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where D represents maximum diameter of the body expressed in mm.


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

4. TOLERANCE FOR VERTICALITY TV (VARIATION FROM THE VERTICAL AXIS - IN ACCORDANCE WITH ISO STANDARD)

The tolerance for verticality (expressed in mm) should be calculated using the following formulas:

a. for a nominal height H < 220 mm

TV = 1.3 + 0.005 H

b. for a nominal height H > 220 mm

TV = 0.3 + 0.01 H

where H is expressed in mm.

5. TOLERANCE FOR NON-PARALLELISM BETWEEN FINISH AND BOTTOM OF THE CONTAINER (IN ACCORDANCE WITH ISO STANDARD)

The tolerance for non-parallelism between the finish and the bottom of the container shall not exceed the values (expressed in mm) indicated in the following table.

FINISH NOMINAL DIAMETER

MAXIMUM TOLERANCE FOR NON-PARALLELISM BETWEEN FINISH AND BOTTOM OF THE CONTAINER

< 20

0.45

from

20 to 30 (INCLUSIVE)

0.6

from

30 to 40 (INCLUSIVE)

0.7

from

40 to 50 (INCLUSIVE)

0.8

from

50 to 60 (INCLUSIVE)

0.9

> 60

1.0

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Testing with the profilometer.

EXTRACT FROM UNI ISO 2859/1 STANDARD

UNI ISO 2859 Sampling procedures for inspection by attributes. Sampling plans indexed by acceptable quality limits (A.Q.L.) for lot-by-lot inspection. UNI ISO 2859/2 and UNI ISO 2859/3 replace UNI 4842. National foreword to ISO 2859/1. This standard has been prepared by the Technical Committee ISO/TC 69 “Application of statistical methods”. It has received majority approval for acceptance by the ISO Council as an international standard. In view of this, the UNI statistical methods Committee for quality has judged that the standard ISO 2859/1 complies with national requirements from the technical point of view. Italian version of standard ISO 2859/1.

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FOREWORD ISO (the International Organization for Standardization) is a worldwide federation of national standard institutions. The development of the International Standards is normally carried out by the ISO technical committees. Any national organization with an interest in a subject for which a technical committee has been established has the right to be represented on that committee. International, governmental and non-governmental organizations, in liaison with ISO, also participate. Draft International Standards adopted by the technical committees are circulated to the regulatory member bodies to be voted on. Publication as an International Standard requires approval by at least 75% of the members casting a vote. ISO 2859 consists of the following parts, under the general title “Sampling procedures for inspection by attributes”: • Part 0:

Introduction to the ISO 2859 attribute sampling system. Sampling plans indexed by acceptable quality limit (A.Q.L.) for lot-bylot inspection. • Part 2: Sampling plans indexed by limiting quality (L.Q.) for isolated lot inspection. • Part 3: Skip-lot sampling procedures. • Part 1:

SUMMARY 1. Goal 2. Normative references 3. Terms, definitions and symbols 4. Expression of nonconformity 5. Acceptable quality limit (A.Q.L.) 6. Submission of product for sampling 7. Acceptance and non-acceptance 8. Drawing of samples 9. Normal, tightened and reduced inspection 10. Sampling plans 11. Determination of acceptability 12. Further information

1. GOAL

This part of ISO 2859 specifies an acceptance sampling system for inspection by attributes. It is indexed in terms of the acceptable quality limit (A.Q.L.).

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Its purpose is to use the economic and psychological pressure of lot non-acceptance to induce a supplier to maintain an average level of process at least as good as the specified acceptable quality limit, while at the same time providing an upper limit for the risk to the consumer of accepting the occasional poor lot. This part of ISO 2859 should not be seen as a procedure for estimating the quality of the lot or for dividing lots according to quality. The sampling plans designated in this part of ISO 2859 are applicable, but not limited, to inspection of: A. finished products; B. components and raw materials; C. operations; D. materials throughout the process; E. supplies in storage; F. maintenance operations; G. data or records; H. administrative procedures.

These schemes are intended primarily to be used for a continuing series of lots, that is, a sufficient series to allow switching of rules to be applied. These rules provide: â&#x20AC;˘ protection

to the consumer (by means of a switch to tightened inspection or discontinuation of sampling inspection), should a deterioration in quality be detected; â&#x20AC;˘ an incentive (at the discretion of the responsible authority) to reduce inspection costs (by means of a switch to reduced inspection), should good quality consistently be achieved.

Sampling plans in this part of ISO 2859 may also be used for the inspection of lots in isolation but in this case the user is strongly advised to consult the operating characteristic curves to find a plan that will yield the desired protection (see point 12.6). In that case, the user is also referred to the sampling plans indexed by limiting the Quality Limits (Q.L.) given in ISO 2859/2.

2. REGULATION REFERENCES

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The following standard regulations contain provisions which are also valid with regard to this standard (ISO 2859) since they expressly include these provisions. The editions indicated below were in force at the moment of publication of this standard regulation. However, parties in agreements based on this standard ISO 2859 are advised to check the possibility of applying the most recent editions of the regulation standards indicated below. The UNI and CEI maintain a list of the International Standards in force on a particular date.


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

3. TERMS, DEFINITIONS AND SYMBOLS

Terms and definitions used in UNI ISO 2859/1 are in compliance with ISO 3534.

3.1 DEFECT

When a quality characteristic in a particular product, process or service does not meet its established quality specifications.

3.2 NONCONFORMITY

When a particular product, process or service does not meet the established quality specifications.

Nonconformities are generally classified according to the level of seriousness as follows: • class

A: nonconformities considered to be of the highest concern for a product or service; acceptance inspections controls should assign a low acceptable quality limit (A.Q.L.) to these types of nonconformity. • class B: nonconformities considered to be less important than those of class A, continuing down in decreasing order of importance.

These can therefore be assigned a higher acceptable quality limit (A.Q.L.) value than those in class A and lower than in class C, if a third class exists, etc..

Note 1 - The term “defect” is limited to nonconformities that lead to a product or service not meeting the specified requirements for the use for which it is intended.

Note 2 - Users are informed that the addition of characteristics and classes of nonconformity will generally affect the overall probability of acceptance of the product.

Note 3 - The number of classes, the assignment to a class, and the choice of acceptable quality limit (A.Q.L.) for each class, should be appropriate to the quality requirements of the specific situation.

3.3 NONCONFORMING UNIT

This is a unit of a product or service containing at least one nonconformity. Nonconforming units must generally be classified according to the seriousness of their nonconformity.

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For example: A: a unit containing one or more class A nonconformities can also contain a class B or C nonconformity. • class B: a unit containing one or more class B nonconformities can also contain class C nonconformities, but no class A nonconformities. • class

3.4 NONCONFORMING PERCENTAGE

Irrespective of the quantity of units produced, the nonconformity percentage is a hundred times the number of nonconforming items divided by the total of product units produced i.e.:

% nonconforming = (no. of nonconforming units/no. of total units) x 100

Note - Sample schemes in the inspection by attributes are indexed by the percentage or fraction of units in a lot (or “batch”) that deviate from the specified requirements, or by the number of the deviations.

In this part of ISO 2859 the terms “percent nonconforming” or “nonconformities per 100 items” are mainly used in place of the theoretical terms “proportion of nonconforming items” and “nonconformities per item”, since the former terms are the most widely used in sampling.

3.5 NONCONFORMITIES PER 100 ITEMS

This is one hundred times the number of nonconformities in the batch (one or more are possible in each product unit) divided by the total number of units produced, i.e.: nonconformity for 100 units = (no. of nonconformities/total units produced) x 100

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3.6 ACCEPTABLE QUALITY LEVEL (A.Q.L.)

This is the level of quality that is the lowest acceptable limit of the average quality level for sampling purposes when a continuing series of lots is submitted for acceptance sampling (see point 5).

3.7 SAMPLING PLAN

This plan indicates the number of units of each batch to evaluate (the number of samples or the number of a sequence of samples) and the relevant criteria for the batch acceptance (this means the number of accepted units Na or the number of rejected units Nr).


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

Note - For the purposes of this part of ISO 2859, a distinction should be made between the terms sampling plan (3.7), sampling scheme (3.8) and sampling system (3.9).

3.8 SAMPLING SCHEME

The set of all the sampling plans with rules for switching from one plan to another.

3.9 SAMPLING SYSTEM

A collection of sampling plans, or sampling schemes. This part of ISO 2859 is a sampling system indexed by lot-size ranges, inspection levels and A.Q.L.s. A sampling system for L.Q. plans is given in ISO 2859/2.

3.10 RESPONSIBLE AUTHORITY

This is a generic term used to maintain the neutrality of this part of ISO 2859 (primarily for specification purposes), irrespective of whether it is being invoked or applied by the first, second or third interested party.

Note 1 - The responsible authority may be: A. the quality department within a supplierâ&#x20AC;&#x2122;s organization (first party); B. the purchaser or buying organization (second party); C. an independent verification or certification authority (third party); D. any of a), b) or c), that may differ according to function (see note 2) as described in a written agreement between two of the parties, for example an agreement between supplier and purchaser.

Note 2 - The duties and functions of a responsible authority are outlined in this part of ISO 2859 (see point 5.2, 6.2, 7, 9.1, 9.3.3, 9.4, 10.1, 10.3).

3.11 INSPECTION

Activity such as measuring, evaluating, examining, or Pass-Fail testing or any other way of comparing the product unit (see 3.14) against the appropriate specifications.

3.12 ORIGINAL INSPECTION

The first inspection of a particular product as distinct from the inspection of a product which has been resubmitted after a previous non-acceptance.

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3.13 INSPECTION BY ATTRIBUTES

Inspection whereby either the product unit is classified simply as conforming or nonconforming with respect to a specified requirement or set of specified requirements, or the number of nonconformities in the product unit is counted.

3.14 PRODUCT UNIT

The element that is examined in order to evaluate its classification as conforming or nonconforming or to calculate the number of nonconformities.

It can be a part of a finished product or the finished product itself. The product unit can coincide with the unit of purchase, supply, production or delivery.

3.15 LOT

A collection of product units, from which a sample is drawn for inspection, to determine if it conforms to the acceptance criteria; it may differ from the collection of product units referred to as a “batch” for other purposes (i.e. for production, delivery, etc.) (see point 6).

Note - “Batch” is another term also used for “lot”.

3.16 LOT SIZE

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Number of product units in a lot.

3.17 SAMPLE

One or more product units selected at random from a lot without reference to their quality. The number of product units in the sample represents the sample size.

3.18 LIMITING QUALITY (L.Q.)

The Limiting Quality is applied when a lot is considered in isolation: it is the quality level which, for the purposes of sampling inspection, corresponds to a low probability of acceptance.

Note - For a particular sampling system (see UNI ISO 2859/2) the acceptance probability of a L.Q. must come within a defined range.


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

4. EXPRESSION OF NONCONFORMITY

The extent of nonconformity shall be expressed either in terms of nonconforming percentage (see 3.4) or in terms of nonconformities per 100 items (see 3.5).

Tables are based on the assumption that nonconformities occur randomly and are statistically independent. There may be good reasons to believe that one nonconformity in an item may be caused by a condition that is likely to cause other nonconformities. In this case, it may be better to consider simply whether the items are conforming or not and to ignore multiple nonconformities.

5. ACCEPTABLE QUALITY LIMIT (A.Q.L.)

5.1 USE AND APPLICATION

The A.Q.L., together with the sample size code letter (see 10.2), is used to index the sampling plans and schemes in this part of ISO 2859. When a specific value of the A.Q.L. is designated for a certain nonconformity or group of nonconformities, the sampling scheme is such that it will accept the majority of the lots submitted, provided that the quality level (nonconforming percentage or nonconformities per 100 items) in these lots is not greater than the designated value of the A.Q.L.. Thus, the A.Q.L. is an established value of the nonconforming percentage (or non conformity per 100 items) which will be accepted most of the time by the sampling plan in force. The sampling plans indicated are arranged so that the probability of acceptance at the designated A.Q.L. value depends upon the sample size for a given A.Q.L., being generally higher for large samples than for small ones. The A.Q.L. is a parameter of the sampling scheme and should not be confused with the average process level that describes the operating level of the manufacturing process. It is expected that the average process level will be lower or equal to the A.Q.L. to avoid excessive rejections under this system.

CAUTION: The designation of an A.Q.L. does not imply that the supplier has the right to supply nonconforming items.

5.2 SPECIFYING A.Q.L.S

The A.Q.L. to be used shall be designated in the contract or established by, or agreed with the responsible authority. Different A.Q.L.s may be designated for groups of nonconformities considered collectively or for individu-

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al nonconformities as defined in 3.2. The classification into groups should be appropriate to the quality requirements of the specific situation. An A.Q.L. for a group of nonconformities may be designated in addition to A.Q.L.s for individual nonconformities, or subgroups within that group. A.Q.L. values lower or equal to 10 can be expressed either in percentage of nonconforming units or as numbers of nonconformities per 100 items; values higher than 10 can be expressed only as nonconformities per 100 items.

5.3 PREFERRED A.Q.L.S

The series of values of A.Q.L.s given in the tables are known as the preferred series of A.Q.L.s. If, for any product, an A.Q.L. is designated as other than one of these values, this standard is not applicable.

6. SUBMISSION OF PRODUCT FOR SAMPLING

6.1 FORMATION OF LOTS

The product shall be assembled into identifiable lots, sub-lots, or in some other way in the order in which it is produced (see point 6.2). Each lot shall, as far as it is practicable, consist of product units of a single type, grade, class, size and composition, essentially manufactured under the same conditions at the same time.

6.2 PRESENTATION OF LOTS

The formation of the lots, the lot size and the manner in which each lot will be presented and identified by the supplier should be designated or approved by the responsible authority, or agreed with them. Where necessary, the supplier shall provide suitable storage space, the necessary equipment for proper identification and presentation, and the necessary personnel for handling the products required for sampling.

7. ACCEPTANCE AND NON-ACCEPTANCE

7.1 ACCEPTABILITY OF LOTS

Acceptability of a lot shall be determined by the use of one or more sampling plans in relation to the A.Q.L. or A.Q.L.s indicated. The term “non-acceptance” is used in this context to mean “rejection”

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when it refers to the result of applying this regulation standard. Forms of the term “reject” are retained when they refer to actions the customer may take, as in “number of rejections”.

The responsible authority will make the necessary decisions on the rejected lots. They can be scrapped, selected (with or without replacement of nonconforming items), re-worked, re-tested under more specific criteria regarding their use, kept for further information, etc..

7.2 NONCONFORMING UNITS

You have the right to reject any product unit judged to be nonconforming during inspection, whether that the item formed part of a sample or not, even if the lot as a whole has been accepted.

Rejected product units may be reworked or corrected and resubmitted for inspection with the approval of, and in the manner specified by, the responsible authority.

7.3 SPECIAL CLAUSES FOR PARTICULAR NONCONFORMITIES

Since the acceptance inspection procedure generally requires an evaluation of several different quality characteristics that may differ in importance as regards the consequences in terms of quality and cost, it is often advisable to identify the types of nonconformity in accordance with the categories indicated in point 3.2. The assignment of the different types of nonconformity to each class depends on the agreement with regard to the specific sampling applications.

In general, the purpose of this classification is to allow the use of a collection of sampling plans which share the same sample size but with different acceptance numbers for each class with its own A.Q.L., as shown in tables II, III and IV. It is at the discretion of the responsible authority to decide whether every product unit in the lot is required to be inspected for particular categories of nonconformity. You have the right to inspect every product unit submitted for particular categories of nonconformity and to reject the lot immediately if a nonconformity of this type is found. You also have the right to sample every lot submitted by the supplier for particular categories of nonconformity and to reject any lot if a sample drawn from it is found to contain one or more of these nonconformities.

7.4 RESUBMITTED LOTS

All parties shall be immediately notified if a lot is found not acceptable. Such lots shall not be resubmitted until all items have been re-examined or retested and

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the supplier is satisfied that all nonconforming product units have been removed or the nonconformities have been corrected. The responsible authority shall determine whether normal or tightened inspection shall be used on re-inspection and whether the re-inspection shall include all types or classes of nonconformity or only the particular types or classes of nonconformities which caused the initial rejection.

8. DRAWING OF SAMPLES

8.1 SAMPLE SELECTION

Under some circumstances the number of units of samples must be selected proportionally according to the number of parts or layers of the batch, following a particular logical criterion. When a layered sample is used, the units of each layer of the batch will be selected at random.

8.2 TIME FOR DRAWING THE SAMPLES

Samples may be drawn after all the product units that make up the lot have been completed, or during production of the lot. In either case, the samples shall be selected at random.

8.3 DOUBLE OR MULTIPLE SAMPLING

When double or multiple sampling is used, each sample should be selected from the entire lot.

9. NORMAL, TIGHTENED AND REDUCED INSPECTION

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9.1 START OF INSPECTION

Normal inspection should be carried out at the start of inspection, unless otherwise directed by the responsible authority.

9.2 CONTINUATION OF INSPECTION

Normal, tightened or reduced inspection shall continue unchanged on the following lots, except when a change is required by the switching procedures (see point 9.3). The switching procedures should be applied to each class of nonconformities or nonconforming product units independently.


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

9.3 SWITCHING RULES AND PROCEDURES

9.3.1 FROM NORMAL TO TIGHTENED

When a normal inspection is being carried out, tightened inspection shall be implemented as soon as two out of five (or fewer than five) consecutive lots have been found unacceptable on original inspection (that is, ignoring lots or batches that have been resubmitted).

9.3.2 FROM TIGHTENED TO NORMAL

(see figure I)

When tightened inspection is being carried out, normal inspection shall be reinstated when five consecutive lots have been considered acceptable on original inspection.

9.3.3 FROM NORMAL TO REDUCED

When normal inspection is being carried out, reduced inspection shall be implemented when all of the following conditions have been met: A. the previous 10 batches (or more, as indicated in the note to table VIII) have been presented for normal inspection and they have all been accepted during the original inspection, and B. the total number of nonconforming units (or nonconformities) in the samples from the previous 10 batches (or from a different number of batches in relation to condition â&#x20AC;&#x153;Aâ&#x20AC;? above) is equal or lower than the appropriate boundary number given in table VIII.

If a double sampling system is adopted, all samples must be considered, not only the first ones, and: C. production is at a steady rate; and D. reduced inspection is considered desirable by the responsible authority.

9.3.4 REDUCED TO NORMAL

When reduced inspection is being carried out, normal inspection shall be reinstated if any of the following occur on original inspection: A. a lot is not accepted, or B. a lot is considered acceptable with the reduced inspection criteria as set out in 11.1.4, or

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C. production becomes irregular or delayed, or D. other conditions warrant that normal inspection shall be reinstated.

9.4 SAMPLING BREAKDOWN

If the number of rejected batches in a sequence of batches submitted to the original tightened inspection amounts to 5, the procedures under the present part of UNI ISO 2589 should be interrupted. Inspection under the criteria of the present part of UNI ISO 2859 will not re-commence until the supplier has taken the necessary measures to improve the quality of the product or service provided. The responsible authority must agree that the action taken has been genuinely effective. Tightened inspection should then be used as if required under point 9.3.1.

10. SAMPLING PLANS

10.1 INSPECTION LEVEL

The inspection level required for any particular application shall be specified by the responsible authority. This allows the authority to require a higher level of discrimination for some purposes and lower for others. At each inspection level, the switching rules shall operate to require normal, tightened and reduced inspection, as specified in clause 9. The choice of inspection level is quite separate from these three methods of inspection.

Three inspection levels, I, II and III, are given in table 1 for general use. Unless otherwise specified, level II should be used. Level I may be used when less discrimination is needed or level III when greater discrimination is required. Four additional special levels, S-1, S-2, S-3 and S-4 are also given in table 1 and may be used where relatively small sample sizes are necessary and larger sampling risks can or should be tolerated.

In the designation of inspection levels S-1 to S-4, care should be taken to avoid A.Q.L.s that are incompatible with these inspection levels. In other words, the purpose of special inspection levels is to allow small samples when necessary. For instance, the code letters under S-1 go no further than D, equivalent to a single sample size of 8, but there is no point specifying S-1 if the A.Q.L. is 0.1%, because the minimum sample size for this A.Q.L. is 125.

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The information about the quality of a lot gained from examining samples drawn from the lot depends upon the absolute size of the samples, not upon the percentage of the lot that is examined, provided the lot is large as compared to the sample.


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In spite of this, there are three reasons for varying the sample size as the lot size changes:

A. when a risk relates to a larger lot, it is more important to make the right decision; B. with a large lot, a sample size can be afforded that would be uneconomic for a small lot; C. truly random sampling requires relatively more time if the sample is too small a proportion of the lot.

10.2 SAMPLE SIZE CODE LETTERS

Sample sizes are designated by sample size code letters. Table 1 should be used to find the applicable code letter for the particular lot size and the prescribed inspection level.

10.3 OBTAINING A SAMPLING PLAN

The A.Q.L. and the sample size code letter should be used to obtain the sampling plan from tables II, III and IV. When no sampling plan is available for a given combination of A.Q.L. and sample size code letter, the tables direct the user to a different letter. The sample size to be used is then given by the new sample size code letter, not by the original letter. If this procedure leads to different sample sizes for different classes of nonconformities or nonconforming items, the sample size code letter corresponding to the largest sample size derived may be used for all classes of nonconformities or nonconforming items, when designated or approved by the responsible authority. As an alternative to a single sampling plan with an acceptance number of 0, the plan with an acceptance number of 1 with its correspondingly larger sample size for a designated A.Q.L. may be used, when designated or approved by the responsible authority.

10.4 TYPES OF SAMPLING PLANS

Three types of sampling plans, single, double and multiple, are given in tables II, III and IV, respectively. When several types of plans are indicated for a given A.Q.L. and sample size code letter, any one plan may be used. A decision as to the type of plan, either single, double or multiple, if available for a given A.Q.L. and sample size code letter, should normally be based on a comparison between the difficulty in administering the different plans and the average sample sizes of the plans.

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For the sampling plans given in this part of ISO 2859, the average sample size of multiple plans is smaller than for a double one and both of these are smaller than the single sample size (see pages 156 and 157). Usually, there is less difficulty in administering single sampling and the cost per sample unit is lower than for double or multiple sampling.

11. DETERMINATION OF ACCEPTABILITY

To determine the acceptability of a lot under nonconforming percentage inspection, the applicable sampling plans shall be used in accordance with 11.1.1, 11.1.2, 11.1.3 and 11.1.4.

11.1 INSPECTION BASED ON NUMBER OF NONCONFORMING UNITS

11.1.1 SINGLE SAMPLING PLANS

The number of sample units inspected shall be equal to the sample size given by the plan. If the number of nonconforming units found in the sample is equal to or less than the acceptance number, the lot shall be considered acceptable. If the number of nonconforming units is equal to or greater than the rejection number, the lot shall be considered not acceptable.

11.1.2 DOUBLE SAMPLING PLANS

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The number of sample items first inspected shall be equal to the first sample size given by the plan. If the number of nonconforming units found in the first sample is equal to or less than the first acceptance number, the lot shall be considered acceptable. If the number of nonconforming items found in the first sample is between the first acceptance and rejection numbers, a second sample of the size given by the plan shall be inspected. The number of nonconforming items found in the first and second samples should be added together. If the total number of nonconforming items is equal to or less than the second acceptance number, the lot shall be considered acceptable. If the total number of nonconforming items is equal to or greater than the second rejection number, the lot shall be considered not acceptable.

11.1.3 MULTIPLE SAMPLING PLANS

In multiple sampling, the procedure is similar to that specified in 11.1.2. In this part of UNI ISO 2859, there are seven stages so that a decision will be reached by the seventh stage at the latest.


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11.1.4 SPECIAL PROCEDURE FOR REDUCED INSPECTION

In the reduced inspection, the sample can contain a number of nonconforming units or of non conformities per 100 units within the numbers of acceptance or rejection. In this case the batch is considered to be acceptable, but ordinary inspection will be reinstated starting from the following batch (see point 9.3.4.b).

11.2 INSPECTION FOR NONCONFORMITIES PER HUNDRED UNITS

In order to determine the acceptability of a lot in this type of inspection, the same procedure specified for nonconforming inspection (see 11.1) should be used, except the term “nonconformities” should be replaced by “nonconforming units”.

12. FURTHER INFORMATION 12.1 OPERATING CHARACTERISTIC (OC) CURVES

The operating characteristic curves for normal and tightened inspection, shown on pages 156 and 157, indicate the percentage of lots which may be expected to be accepted under the various sampling plans for a given process quality level.

The operational curve which characterizes an unqualified acceptance in the reduced inspection (when the number of nonconforming units is lower or equal to the acceptance number) can be found using the A.Q.L. of the ordinary plan with the sample size/s and number/s of acceptance of the reduced plan. The curves shown are for single sampling; curves for double and multiple sampling are practically identical.

The OC curves shown for A.Q.L.s greater than 10 are based on the Poisson distribution and can be applied to nonconformities per 100 units; curves for A.Q.L.s of 10 or lower and sample sizes of 80 or lower are based on the binomial distribution and can be applied to inspection by nonconforming %; the curves of A.Q.L. 10 or lower and sample sizes higher than 80 are based on the Poisson distribution and can be applied both to nonconformities per 100 units and to nonconforming % (the Poisson distribution is a good approximation of the binomial distribution under these conditions).

The levels in the tables, corresponding to pre-set levels of probability of acceptance Pa (expressed in %), are indicated for each OC curve in the tables, including for tightened inspection, for nonconformities per 100 units for A.Q.L.s of 10 or lower and for sample sizes of 80 or lower.

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12.2 AVERAGE PROCESS LEVEL

The average process level can be estimated by the average nonconforming percentage or average number of nonconformities per 100 items (whichever is applicable) found in the product samples submitted by the supplier for original inspection, provided that inspection was not curtailed. When double or multiple sampling is used, only first sample results shall be included in the average process estimation.

12.3 AVERAGE OUTGOING QUALITY (AOQ)

The average outgoing quality is the average quality of the outgoing product, including all accepted lots, plus all lots which are not accepted, after such lots have been effectively 100% inspected and all nonconforming items replaced by conforming items.

12.4 AVERAGE OUTGOING QUALITY LIMIT (AOQL)

The AOQL is the maximum value of the average outgoing qualities for all possible qualities submitted for a particular acceptance sampling plan. Approximate AOQL values are given in table V-A for each of the single sampling plans for normal inspection and in table V-B for each of the single sampling plans for tightened inspection.

12.5 AVERAGE SAMPLE SIZE CURVES

Average sample size curves for double and multiple sampling, as compared with the corresponding single sampling plan for each acceptance number, are given on pages 156 and 157.

These curves show the average sample sizes which may be expected to occur under the various sampling plans for given levels of process quality. The curves assume that the inspection is not interrupted.

12.6 PROTECTION BY MEANS OF LIMITING QUALITY (LQ)

12.6.1 USE OF INDIVIDUAL PLANS

208

This part of ISO 2859 is designed to be used as a system of rules employing tightened, normal and reduced inspection on a successive series of lots to achieve customer protection while assuring the producer that acceptance will occur most of the time if quality is better than the A.Q.L..


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

Occasionally, single plans are selected from this part of ISO 2859 and used without the switching rules. For example, a purchaser may be using the plans for verification purposes only. This is not the intended application of the system given in this part of ISO 2859 and its use in this way should not be referred to as “inspection in compliance with ISO 2859/1”. When used in this way, this part of ISO 2859 simply represents a repository for a collection of individual plans indexed by A.Q.L..

The operating characteristic curves and other parameters of a plan chosen in this way should be established by each interested party taking the appropriate information from the tables provided.

12.6.2 LIMITING QUALITY TABLES

If a lot (or “batch”) is by its nature isolated, it may be advisable to limit the selection of sampling plans to those that in addition to being associated with a designated A.Q.L. value, also give a level of protection that is no lower than a given limiting quality. Sampling plans for this purpose can be selected by choosing a Limiting Quality (L.Q.) and a consumers risk quality (CRQ) associated with it. For the definition of a Limiting Quality (see 3.18). Tables VI and VII give the nonconformity levels for which probability of acceptance of the lot are 10% and 5% respectively.

For individual lots with nonconforming percentage or number of nonconformities per hundred equal to the established limiting quality, the probability of lot acceptance is lower than 10% in the case of the plans listed in table VI and of 5% for the plans listed in table VII.

When there is a reason to avoid more limiting percentages of nonconforming product units (or nonconformities) in a lot, tables VI and VII may be useful for establishing the minimum sample sizes to be associated with the A.Q.L. and the specified inspection level for a continuous series of lots. For example, if an L.Q. of 5% is required for individual lots with an established probability of acceptance of 10% or less, table VI indicates that the minimum sample size shall be given by sample size code letter L. UNI ISO 2859/2 provides further details of the sampling methods for isolated lots.

209


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

FIGURE 1 DIAGRAM OF THE SWITCHING RULES

START • THE PREVIOUS 10 LOTS INSPECTED WITH ORDINARY INSPECTION AND • ACCEPTED WITH A TOTAL NUMBER OF NONCONFORMING UNITS (OR NONCONFORMITIES) EQUAL TO OR LOWER THAN THE A.Q.L., AND • CONSTANT PRODUCTION, AND • AGREEMENT OF THE RESPONSIBLE AUTHORITY

REDUCED INSPECTION

ORDINARY INSPECTION

• LOT NOT ACCEPTED OR • LOT ACCEPTED BUT WITH A NUMBER OF NONCONFORMING UNITS (NONCONFORMITIES) BETWEEN THE ACCEPTANCE NUMBER (AN) AND REJECTION NUMBER (RN) OF THE PLAN OR • IRREGULAR PROCESS OR • OTHER CONDITIONS REQUIRE A SWITCHING OF RULES

210

2 LOTS OUT OF 5 (OR LESS) CONSECUTIVE LOTS NOT ACCEPTED

TIGHTENED INSPECTION

5 CONSECUTIVE LOTS ACCEPTED

5 LOTS NOT ACCEPTED IN THE TIGHTENED INSPECTION

INTERRUPTION OF INSPECTION

THE SUPPLIER IMPROVES QUALITY


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

TABLE I: SAMPLE SIZE CODE LETTERS (SEE POINTS 10.1 AND 10.2)

SPECIAL INSPECTION LEVELS

BATCH SIZE

CURRENT INSPECTION LEVELS

S-1

S-2

S-3

S-4

I

II

III

FROM 2

TO 8

A

A

A

A

A

A

B

FROM 9

TO 15

A

A

A

A

A

B

C

FROM 16

TO 25

A

A

B

B

B

C

D

FROM 26

TO 50

A

B

B

C

C

D

E

FROM 51

TO 90

B

B

C

C

C

E

F

FROM 91

TO 150

B

B

C

D

D

F

G

FROM 151

TO 280

B

C

D

E

E

G

H

FROM 281

TO 500

B

C

D

E

F

H

J

FROM 501

TO 1,200

C

C

E

F

G

J

K

FROM 1,201

TO 3,200

C

D

E

G

H

K

L

FROM 3,201

TO 10,000

C

D

F

G

J

L

M

FROM 10,001 TO 35,000

C

D

F

H

K

M

N

FROM 35,001 TO 150,000

D

E

G

J

L

N

P

FROM 150,001 TO 500,000

D

E

G

J

M

P

Q

FROM 500,001 AND OVER

D

E

H

K

N

Q

R

211


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

TABLE II A MASTER TABLE FOR SINGLE SAMPLING PLANS FOR NORMAL INSPECTION (SEE POINT 10.1 AND 10.2)

Sample size code letter

Sample size

ACCEPTANCE QUALITY LEVELS (NORMAL INSPECTION)

A B C

2 3 5

D E F

8 13 20

G H J

32 50 80

K L M

125 200 315

N P Q

500 800 0 1 1250 0 1

0 1

R

2000

1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22

0.010 0.015 0.025 0.040 0.065 0.10

0.15

0.25

0.40

0.65

1.0

An Rn An Rn An Rn An Rn An Rn An Rn An Rn An Rn An Rn An Rn An Rn An Rn

0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

1 2 1 2 2 3 1 2 2 3 3 4

1 2 2 3 3 4 5 6 1 2 2 3 3 4 5 6 7 8 1 2 2 3 3 4 5 6 7 8 10 11

1 2 2 3 3 4 5 6 7 8 10 11 14 15 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22

= Use the first sampling plan below the arrow. If the sample size equals, or exceeds, lot size, carry out 100% inspection. = Use the first sampling plan above the arrow.

An = Acceptance number Rn = Rejection number

212

1.5


6. QUALITY SUPPLY SPECIFICATIONS (TERMS, DEFINITIONS, METHODS)

ACCEPTANCE QUALITY LEVELS (NORMAL INSPECTION) 2.5

4.0

6.5

10

15

25

40

65

100

150

250

400

650 1000

An Rn An Rn An Rn An Rn An Rn An Rn An Rn An Rn An Rn An Rn An Rn An Rn An Rn An Rn 0 1 0 1

0 1

1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31 44 45 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31 44 45

1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31 44 45 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31 44 45 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 2 3 3 4 5 6 7 8 10 11 14 15 21 22 3 4 5 6 7 8 10 11 14 15 21 22 5 6 7 8 10 11 14 15 21 22 7 8 10 11 14 15 21 22 10 11 14 15 21 22 14 15 21 22 21 22

213


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Special thanks to all the people involved in producing the photographs in this book. This book is a contribution to the research into one of the most important of all packaging materials: glass. © Bruni Glass spa - Milan, 2015 “All rights reserved. The reproduction, even partial, of this manual is prohibited”. GRAPHIC DESIGN BY


TRANSPARENCIES 2.O  

PROCESSES SHAPES MATERIALS

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