FPT 3 2022

Optimization of flexo process parameters to reduce the overall manufacturing cost Recycling Of Printed Papers And Usability In Flexo Printed Packaging

Total Productive Maintenance Analysis on Printing Machine (Case Study)

Standard Bag: A not so standard story

Comexi enters the digital printing sector with new press

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This study aimed to determine whether 100% recycled papers can replace papers made from virgin fibers for the purpose of electrophotographic printing for packaging by evaluating the recycling potential of electrophotographically printed paper using the INGEDE and the washing deinking method.

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The flexo process parameters play an important role in ink transfer and will lead to wastage of inks, substrate, solvents and printed stocks if not monitored and controlled.

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This report covers the print for packaging market over the period 2017– 2027. It explores the restraining factors in play, including the increasing demand for more sustainable packaging; this will alter patterns of demand between packaging materials, as well as restraining overall demand in the market to some extent.

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The 8th drupa Global Trends Report will be published in September 2022. The first results from a survey conducted this spring are now available. One important conclusion: overall, confidence is on the rise and all regions and markets forecast higher investment in 2023.

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PT XYZ is one of Indonesia’s major flexible packaging manufacturer companies. The company suffers losses from the increase in printing machine breakdown from 1.65% in 2019 to 2.52% in 2021. This paper aims to reduce the breakdown duration in 2022 by identifying and solving the root cause by implementing one of the alternative solutions.

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At Oregon-based Standard Bag, a 37-year-old family-run company, the addition of a brand new MIRAFLEX II is opening the door to new possibilities and opportunities.

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After nearly 70 years manufacturing capital goods for the flexible packaging converting industry, Comexi is taking a step forward: fully moving into digital technology. At K 2022, the company will present the Digiflex press, its first digital printing solution that enables the flexible packaging industry to meet the current needs of a changing and increasingly demanding market.

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Recycling Of Printed Papers And Usability In Flexo Printed Packaging The This study aimed to determine whether 100% recycled papers can replace papers made from virgin fibers for the purpose of electrophotographic printing for packaging by evaluating the recycling potential of electrophotographically printed paper using the INGEDE and the washing deinking method. In the first part of the study, typical office copy paper, containing up to 30% recycled fiber, was printed electrophotographically. In the second part of the study, the deinked pulp was then used to prepare the handsheets for deinking evaluation, paper analysis and printability analysis. The print quality of the recycled papers was highly encouraging, as the results were comparable and, in some cases, identical to those of papers manufactured from virgin fibers.

By SINAN SONMEZ, SWATI SOOD, MATTHEW STOOPS, PAUL D. FLEMING III, KECHENG LI, QINGLIU WU and ABDUS SALAM The traditional method of producing paper from pulp derived from raw wood is unprofitable and unsustainable.1 The UN environment program proposes many solutions and goals to help ensure sustainability on earth, including the 12th goal – Sustainable consumption and production. It

aims to detach economic growth from environmental damage, boost resource efficiency, support the shift to lowcarbon and green economies, and promote sustainable lifestyles.

Recycling of paper is one of the ways to fulfill this goal.2 For more than 30 years, recycled paper has been sold in

the market.3 It is one of the best solutions to lessen environmental issues and waste generation.

Recycling decreases the need for new raw materials and prevents the loss of potentially useful resources.4 The Delft University of Technology has conducted a lot of research on the circular

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economy regarding packaging. The university is the founder of the 4R approach, which stands for “recycle, reuse, renew, and rethink.” Recycling in this context refers to using waste packaging materials to create new packaging.5 As the need for packaging board has expanded globally, a significant amount of secondary cellulose raw materials have been produced; these materials make up 25–40% of the municipal solid waste (MSW) that is disposed of in landfills and burned. Because of the production of harmful gases and contaminating leachate, these methods of disposal are not environmentally friendly.

Forest resources can be preserved and other environmental effects can be reduced by recycling these fiber sources and using them as raw materials for new sustainable products.6,7 Paper recycling is a major priority for many nations

worldwide. China, for instance, has set up a market-driven paper recycling system. More than several million tons of recovered pper are being recycled in the USA and Japan.4 Most countries also have their own policies or laws on recycling, for example, Japan has a rigid law called Containers and Packaging Recycling Law to control the wastes in their country.8 In Malaysia, the Solid Waste Management and Public Cleansing Corporation Act (SWCorp) was established by the government to support and ensure the successful implementation of the National Solid Waste Management Policy.9 Therefore, efficient use of waste paper might not only minimize the amount of MSW, but also help preserve and safeguard the environment.7 Additionally, the current approaches to waste management are moving away from waste disposal towards recycling, reusing, and

recovering. According to Bajpai, every ton of recycled paper that replaces a ton of virgin fiber results in a 100% decrease in wood use, a 33% reduction in wastewater, a 27% reduction in energy consumption, a 28% reduction in air particle emissions, and a 54% reduction in solid waste. This series of data shows the importance of waste paper recycling.10 As a result, recycling waste paper is becoming more and more popular as a resource-saving and environmentally responsible option to producing pulp and paper. However, sometimes recycling of recovered paper has a detrimental impact on the quality of the paper, for instance, recycled paper has a far lower quality than paper generated from virgin pulps because the fibers are shorter and have less tensile strength.10 Paper fibers cannot be recycled continuously since they get damaged in the handling and recycling process. Accord-

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ing to some researchers, fibers can be recycled up to seven times.11 Every year, the paper industry uses 19 million tons of recycled paper to make containerboard, however, with every fiber reprocessing cycle, mechanical characteristics degrade because of the resistance of fiber to swelling when it is rewet after being dried.12 Papers made from recycled fibers present changes in brightness over time and may turn yellow.11 Some drawbacks in the quality of recycled paper are perceived by the user, such as its opacity (which affects strikethrough or seethrough on double-sided printing), mechanical properties, and printer longevity. The impact of various paper properties that contribute to the print quality of the recycled paper is covered in this paper. An improvement in print quality would encourage more people to use recycled paper.3 The majority of paper characteristics al-

so affect how well paper prints electrophotographically. An increase in basis weight, brightness, caliper, density, hardwood fiber content (%), fluorescence, gloss, opacity and porosity would improve print quality, whereas an increase in Parker Print-Surf (PPS) roughness would have the opposite effect.13 Electrophotography is a dynamic technique that is frequently utilized in copiers, fax machines, and digital printers. It is an imaging technology that uses a photoreceptor, light source, electrostatic principles, and toner to print a digital

file as an output. Despite numerous technological advancements throughout the years, the fundamental technique of electrophotography has essentially re-

mained unaltered.14 The color gamut of electrophotographic digital printing is influenced by a number of factors, such as the printer, the toner, and particularly,

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the characteristics of the paper (such as its whiteness, roughness, and gloss), which have an impact on the final color gamut and replication quality.15 The aim of this study is to perform electrophotographic printing on recycled paper using different deinking methods and analyze the optical, physical, and color variations of the resulting sheets after each recycling stage. Additionally, the properties and printing parameters of the printed papers are

compared. Such studies are crucial for the paper, printing, and packaging industry, which is struggling from a lack of raw materials, as well as other financial and environmental issues.

EXPERIMENTAL Sample The sample used in this study consisted in recycled papers (electrophotographically printed papers containing up to 30% recycled fiber) with the basis weight of 80 gsm. The

sample papers were printed with an HP LaserJet Printer (P3015) having HP proprietary dry toner. The content of the sample was printed as 11-point Sans Serif Type, single line spacing, as shown in Figure 1. Each recycled paper was printed on one side, so that the print area represented at least 50% ink coverage, and these prints were then deinked to prepare the recycled handsheets for flexo printing.16

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Deinking conditions The samples were deinked using two different deinking methods: the INGEDE (International Association of the Deinking Industry) method 11, which is a wellrecognized method to evaluate the recyclability of waste paper in Europe,17 and the washing method. To perform the INGEDE method,

the samples were aged in the oven for 72 hours at a constant temperature of 60 °C, disintegrated, and surfactants were added. The surfactants contained NaOH (0.6%), Na2SiO3 (1.8%), H2O2 (0.7%), and C18H34O2 (0.8%).

The recycled pulp slurry that was obtained was diluted to 0.8% Cy and deinked in a Voith flotation cell for 12 minutes.

In the washing method

(WM), the sample was aged in the oven in the same way as in the INGEDE method (the sample was kept for 72 hours at a constant temperature of 60 °C).

Thereafter, the sample was diluted to 0.8% Cy to form a pulp slurry.

This pulp slurry and the displector deinking chemicals, which consisted of a combination water, sodium alkyl sulfate (SAS), specially de-

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natured (SD) alcohol, sodium alkyl ethoxylate sulfate, and alkyl dimethyl amine oxide (ADAO), were introduced into the Voith flotation cell (Fig. 2) and the deinking process was performed for 12 min.

Once the deinking process was complete, the pulp was taken out of the flotation cell and was weighed to determine the pulp yield.

Sufficient handsheets were then prepared from the deinked pulp (by following the TAPPI Standard T205) and conditioned at 23 ºC, 50% relative humidity for 24 h. The handsheets were then evaluated for deinking efficiency, paper properties (mechanical, optical, and surface properties), and printability (color, optical, brightness, and print performance analysis). The samples were also tested for Parker Print-Surf (PPS) porosity (which actually measures air permeability19) by using the PPS tester at 1000 kPa

clamping pressure (CP) with a soft backing.

Thickness in micron was determined using a TMI Micrometer. Roughness in micron was assessed using a PPS ME-90 (1000 kPa, soft backing) based on TAPPI T555OM-99. Gloss percent was measured at 75º using a Novo-Gloss™ Glossmeter based on TAPPI standard T480OM-99. CIE L*a*b* color values were measured using an X-rite EXact device in M1 mode, and brightness – with a Technidyne Brightimeter Micro S-5 based on TAPPI Standard T452-OM98 (457 nm light). In the end, all the experimental values obtained for the handsheets were compared with those for the base commercial paper.

Printing conditions The test samples were printed using a Flexiproof 100 device with cyan commercial ink, provided by Wikoff Color Corporation. For printing, a flexible photopolymer printing plate was

used (size 260 x 90 mm, thickness 1.7 mm and screen frequency 39.37 l/cm (100 lpi)); the digital file shown in Figure 3 was used to print. Prints were carried out at 40 m/min printing speed, 45 units pressure between the anilox roller and the plate cylinder, and 50 units pressure of between the plate cylinder and the impression cylinder. An anilox cylinder with screen frequency of 200.6 l/cm (510 lpi) was used to meter the ink to the plate. The capacity of its ink-cells was 5 cm3/m2.20 The values of print density, print contrast, dot gain and CIE L*a*b* values were measured with an X-rite EXact device, using M1 mode, D/50 light source under an observation angle of 2° after printing. For calculating delta gloss, the unprinted and printed gloss values were measured at 60º using a BYK micro-gloss meter based on TAPPI standard T480 -OM-99.21 Dot roundness was determined

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using Paxit software. In the study, the following abbreviations were used: BP – for base paper, WMUPD – for deinked unprinted paper produced using the washing method, WMPUD – for undeinked printed paper produced using the washing method, WMPD – for deinked printed paper produced using the washing method, IMUPD – for deinked unprinted paper produced using the INGEDE method 11, IMPUD – for undeinked printed paper produced using the INGEDE method 11, and IMPD – for deinked printed paper produced using the INGEDE method 11.

These abbreviations are used in the tables and figures.

RESULTS AND CUSSION

DIS-

Physical and optical properties of paper Table 1 presents the physical properties of the handsheets obtained by using the

washing method and the INGEDE method.

The shortening in the fiber lengths due to the fragmentation after deinking of the long fiber ratio present in the base paper caused an increase in the PPS porosity value. The reason for the increase in the porosity values for the INGEDE method, compared to the washing method, is that the chemicals used in the ink removal process increased the rate of fragmentation in the fibers.

In addition, the toner particles, which could not be removed from the environment as a result of deinking, closed the existing gaps between the fibers, resulting in a decrease in the porosity values. It is seen that the surface roughness values of the handsheets deinked by the INGEDE method are slightly lower than those of the handsheets subjected to the washing method. If the handsheets obtained are passed through a calen-

dering process, there will be an increase in the surface smoothness of the handsheets for both deinking methods.

The tensile index values of the handsheets (for both the washing method and the INGEDE method) were lower than those of BP, because of the damage produced to the fibers.

However, when the burst indices are compared, the values corresponding to the INGEDE method are slightly lower than those of the washing method.

In both methods, it is seen that the burst index increases in PD, compared to PUD. This increase indicates a positive result of the removal of pigment particles from the environment.

Regarding the tear index, it is seen that there is an increase in the strength values after deinking. The choice of the deinking method did not lead to significant differences in the tensile index. It has been determined that the re-

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sistance properties of the papers produced using the washing method are slightly higher than those of the papers produced using the INGEDE method (Table 2). The data in Table 3 reveal that the brightness values of UPD handsheets are higher than those of BP for both deinking methods used. This increase is due to the removal of OBA present in the environment during the deinking process. It was determined that the brightness values of PD and UPD handsheets were affected positively by the INGEDE method, compared to the washing method, and the removal of toner particles from the pulp increased the brightness values for both methods. On the other hand, the increasing amount of toner particles in the pulp also increased the opacity values. It was determined that the washing method increased the brightness of the handsheets, compared to INGEDE, and there was

an increase in the gloss values in direct proportion to the toner particles removed from the pulp. The CIE L*a*b* color values of the original copy paper and handsheets are shown in Table 4. By keeping constant the CIE L*a*b* color values of the original copy paper, the paper color difference value (฀E00) was calculated using Equation (1): (1) where RT = a hue rotation term; KL, KC and KH = parametric factors; L*C*h = compensation for neutral colors, SL = compensation for lightness, SC = compensation for chroma, SH = compensation for hue. According to these calculated values, ฀E00 of 1.46 was obtained for WMUPD,

฀E00 6.88 for WMPUD, ฀E00 1.60 for WMPD, ฀E00 2.52 for IMUPD, ฀E00 5.85 for IMPUD, ฀E00 2.99 for IMPD. These values show that the handsheets deinked using the WM have the closest color tone to the color values of the BP. This obtained color difference indicates that OBA in the recycling pulp was better removed by INGEDE, compared to the washing method. In order to calculate the deinking evaluation factor (DEMLab), the color values in the CIE L*a*b* color system of unprinted paper and printed handsheets are used.

For the calculation of the deinkability factor (DEMf) value, the brightness values are

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used. The DEMLab and DEMf deinkability factors are given in Equations (2) and (3). The deinking evaluation factor (DEMLab) was calculated using Equation (2):22,23 ] (2) where US – unprinted deinked pulp, BS – printed undeinked pulp, DS – deinked pulp.

The deinkability factor (DEMf) was calculated using Equation (3):17 (3). The deinkability factors are in the range of 0- 100%, values close to 100% indicate excellent ink removal, and values close to 0% indicate poor deinking.

The deinkability efficiencies of the prepared handsheets are given in Table 5. These values show that higher efficiency was obtained by the washing method than by the INGEDE method. However, it has

been determined that INGEDE is more efficient than the washing method in terms of brightness. VERITY IA Light and Dark Dirt 3.4.0 software was used to determine the dirt count in undeinked and deinked handsheet papers. For use of the software, handsheets were first scanned at 1200 ppi using the Epson Perfection V750 Pro scanner. The minimum speck area settings are defined as 0.02 (T563) and 0.007 mm2. The other dirt analysis settings are: shape (12.57300, 12.57 is perfect circle); luminance (0190); and threshold is the background mode minus 30.24 The ink elimination factor (IEERIC) was calculated using Equation (4): (4) where UP – undeinked pulp, DP – deinked pulp,

UNPR – unprinted pulp.

The obtained dirt area and ink elimination factors are given in Table 6. When comparing unprinted pulp, the dirt area was slightly higher for the WM than for IM. However, the dirt areas of undeinked and deinked pulps using WM were lower than those for IM. When the ink elimination factors were examined, WM showed better results by 1% compared to IM. In the images given in Figure 4, the difference between WM and IM is seen clearly.

Print density Density represents the ability of ink to absorb light. Thus, measuring the light reflected from the ink printed surface gives the print density.

The resulting value indicates how dark the re-

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sulting color appears after printing. A thick ink layer indicates that the ink has a strong ability to absorb light. The higher this value, the higher the density value.25,26.

As may be seen in Figure 5, the BP density value is higher than those for both deinking methods. This is due to the surface roughness and porosity of BP being lower than those of produced handsheets. The lower density value of WMPUD is due to the higher surface roughness, compared to those of the other produced handsheets.

Since the amount of pigment remaining on the surface will be higher in a substrate with a high surface smoothness and a low air permeability structure, the resulting print density value will be higher. It was determined that the deinking method did not have a significant impact on the print density value.

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Print contrast Print contrast is defined as the capacity of image detail obtained in the shadow regions of images printed on a printing system. The print contrast with the lowest dot gain at the highest ink density is the ideal value.27 The ratio of the difference between the density of the solid print area and the printed shadow tint area to the solid density gives the print contrast value and this ratio is expressed as a percentage.28 The values pre-

sented in Figure 3 were obtained by comparing the solid and 75 percent dot density values. With the print contrast value, the better ink density of the flexo plate can be controlled. In this, it is important for the flexo plate to receive the right amount of ink from the anilox roll during printing. Figure 6 shows that the toner particles in the undeinked handsheets have reduced the print contrast value. The removal of toner particles from the pulp increased the print contrast. The

print contrast value obtained after deinking is higher than that of the BP. The different deinking methods used made a significant impact on the print contrast.

Tone value increase (TVI)

Tone values are used to obtain colors in multicolored works. Although these values are at a certain level during the design, they exhibit an increase as a result of the printing process.

This is called tone value

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increase (TVI) in the printing industry.29,30 For this reason, while designing the file to be printed, the necessary tone value selections should be made by keeping the TVI in mind. During this selection, elements, such as paper type, printing type, the ink to be used etc., must be taken into account.31 Dot gain or TVI has two basic components (Fig. 7): the first is the mechanical dot gain, which occurs as a result of the physical spreading of the ink under pressure, and the other is the optical dot gain, which is formed by the shadow of the light in the substrate around the dot.32 TVI values close to each other were obtained in the hand-

sheets obtained by both methods, except IMPUD, which showed the lowest TVI values. The smoothness of the surface is very important in obtaining dots with sharp lines and without ink loss. If the handsheets are passed through the calendering process, the surface smoothness will increase and quality dots can be obtained (Fig. 8).

Print chroma The degree of departure of a color from a neutral color of the same value is called “chroma”.34 The chroma value gives information about the saturation of that color.

Low chroma implies weakly saturated color, while high chroma stands for highly saturated color. The units of chroma are dimensionless.35,36

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Figure 9 shows that the print chroma values of the handsheets obtained after deinking increased for both deinking methods. It is seen that the print chroma value of the handsheets obtained as a result of deinking by the washing method is higher. Therefore, higher saturation prints can be obtained.

Table 7 illustrates the CIE L*a*b* color values of printed handsheets.

The values of ฀E00 Print was calculated by Equation (1). According to these calculated values, ฀E00 of 5.16 was achieved in WMUPD, ฀E00 2.62 – in WMPUD, ฀E00 7.49 – in WMPD, ฀E00 5.74 – in IMUPD, ฀E00 1.68 – IMPUD, and ฀E00 8.66 – in IMPD. These values reveal that the printed handsheets from undeinked pulp have the lowest ฀E00 Print, because both methods include OBA to some extent. Thus, the print color is the closest color tone to the color values of the BP. IM yields bet-

ter ฀E00 Print than WM achieved by the washing in the case of undeinked method, while the printed papers.

INGEDE method led to higher DEMf%. When CONCLUSION comparing the CIE The recycling, which L*a*b* color values of was conducted on typi- printed handsheets, the cal electrophotographic L* value was the highfor IMPUD, BP office copy paper, had a est positive influence on se- showed the highest a* lected optical, mechani- value, and WMPUD – cal, and printing proper- the highest b* value, ties of the paper. The while ฀E00 print was findings revealed that observed to be the the roughness was the highest in WMPD. The between highest in the WMPUD differences handsheets, while the 100% recycled papers thickness, PPS porosity, and papers made of virand permeability were gin fibres were exthe highest in the IM- tremely small, as 100% papers PUD handsheets. For recycled high print the samples studied, achieved the tensile index, burst- quality. Based on the ing index, and tearing findings of this study reindex remained the garding print quality, highest for the BP. 100% recycled sheets Brightness and opacity might completely rewere the highest in place papers made from WMUPD, while gloss re- virgin fibers for use in mained the highest for electrophotographic the BP. As regards the printing in regular office CIE L*a*b* color val- settings, as well as in ues, IMUPD exhibited flexography in packagthe highest value of L*, ing. The variations in the BP had the highest flexo printing paramevalue of a*, and IMPD – ters are totally explainathe highest value of b*. ble in terms of residual Higher DEMLab% was toner or ink.

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Optimization of flexo process parameters to reduce the overall manufacturing cost The flexo process parameters play an important role in ink transfer and will lead to wastage of inks, substrate, solvents and printed stocks if not monitored and controlled. The work focuses on optimizing the flexo process parameters for 40 microns 3-layer polyethylene (PE) film with Blue Nitrocellulose (NC) ink to reduce overall manufacturing cost while maintaining the print quality for diaper application. An experimental design was conducted for the response Ink GSM (grams per square meter), ΔE and Print Mottle with factors such as ink viscosity, anilox volume, plate dot shape and substrate opacity. The data was analyzed through Main Effect, Interaction Plot and Analysis of Variance (ANOVA). The regression models were developed for the response to validate the predictive ability of model.

The process optimization resulted in reduction of Ink GSM, ΔE and Print Mottle by 18%, 52% and 1% respectively. The ink consumption reduced by 18.26% with minimized print defects, thereby reducing the overall manufacturing cost.

The As per Mordor Intelligence Report [1], the growth of flexography printing market will be 2.44% CAGR within a period from 2021 to 2026 which accounts to 124.61 USD billion from 107.42 USD billion. A large part of the flexography indus-

try clientele remains to be from the industry catering to the needs of people i.e. personal care products like baby diapers. The India Diaper Market Outlook 2021 [2] reports 22.23% CAGR in baby diaper market over past 5 years. There are al-

most 25 million babies born every year. The hygiene awareness of Indian mothers, rise in income of common people has led to an exponential growth in diaper market. These diapers are packaged in pouches that are printed on Polyethylene (PE) and

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Cast Polypropylene (CPP) films using NC based inks by Flexo process. The surface anomalies and print defects, plate fill-ups, frequent machine stoppages, shade inconsistency is one of the major challenges during printing these films. This results in print mottle, uneven print density and ink deposition, thereby depreciating the print quality and degrading the selling potential of the product. Furthermore, the overall manufacturing cost inclusive of printing, converting and process scrap cost is high. This demands for optimization with tight control of flexo process parameters to minimize the total manufacturing cost with improved print quality.

Flexography printing the ink tray and carries process the ink in its cells to the flexible plate mounted Flexography is a printon a sleeve. In this proing process which utilizcess, ink gets transes a flexible relief plate ferred from anilox roller that adheres to a printto the raised areas of ing cylinder. The usage the plate and thus inkof flexible (soft) printing ing only the image porplates and low viscosity tion. This image area inks prints on a wide then comes in contact range of absorbent and with the substrate and non-absorbent subtransfers the image onstrates such as plastics, to it by thrusting itself metallic films, paper against the impression and board. These plates roller (Figure 1). The are mounted on sleeves pressure between the that receive ink from plate cylinder and the the ink pan through an impression roller is anilox roller. An anilox termed as kiss pressure roller is a cylinder conand should be just sisting of fixed number enough to transfer ink of cells with a definite from plate to substrate volume. A doctor blade [3]. is used to control the amount of ink trans- Flexography process ferred to the anilox roll- parameters er. It wipes out any exThe parameters that aftra ink is collected back fect ink transfer in flexto the ink tray. The ography and printability anilox roller rotates in

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include plate, anilox, ink, substrate, solvents, press speed, surface energy of substrate etc.

The printability attributes include density, Tone Value Increase, color deviation (Delta E), gloss, ink coat weight (GSM) and print mottle. Several works have been conducted by researchers to obtain the optimum print quality in the flexography print process [4-15].

The cost of print can be easily reduced by increasing the ink mileage and optimizing the flexo process parameters.

anilox roller cell volume [5]. A thinner ink film is deposited on the substrate at higher anilox line screen that carries more no. of cells in a given area. This results in less ink transfer due to cell clogging, anilox scoring, and anilox wear. The lower line screen and volume led to a smoother cell surface with consistent ink transfer and print performance. There exists a direct relation between the coating deposit and the volume of the anilox. The ink transfer is governed by type of anilox engraving The anilox roller is the techniques, inking sysheart of flexography process and plays a significant role in ink transfer. The 60-deg hexagonal pattern are shallower and accommodates 15% more cells as compared to 300 hex,450 tri-helical and 700 cell angles. The 600 hex cells provide better dot support during printing with greater uniformity [4]. The flexo ink transfer is directly proportional to the

tem and plate-making.

These parameters allow to accommodate finer screen volume with lower cell volume [6-9].

The ink film thickness in flexography process depends upon the anilox volume measured in billion cubic microns. The transfer of ink from anilox to plate is almost 50% and further transfers 50% of the ink from plate to the substrate [3, 10]. In order to avoid print defects such as dirty print and dot dipping, banded anilox test should be performed with varying anilox screen and cell volume to identify the

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right specification of anilox roller for optimal ink transfer [11]. The laser engraved ceramic coated anilox roller has better release properties as compared to mechanically engraved chrome anilox roller.

The quality of ink laydown improves with ceramic coated anilox rollers [12]. The print consistency shall be achieved by the right selection of anilox screen ruling, volume and cell geometry [13].

The type of coating and polarity of substrate has a significant effect on print gloss and density.

The coating on the substrate provides higher gloss as compared to uncoated substrate. The print density on uncoated substrate is inconsistent due to the ink deposition on the rough areas of the substrate.

The presence of coating on the substrate leads to even lay-down of an ink. The print density increases with higher polarity of the substrate [14].

The ink film thickness and tone value increase in flexography is affected by the type of substrate, ink and viscosity.

The print density increases for both solvent and water based flexo inks with the increase in anilox volume.

The coated substrate reproduces higher print density with solvent-based inks as compared to water-based inks while the behavior is opposite for uncoated substrate. A higher tone value increase is noted with water-based ink on coated substrate as compared to solvent-based ink which is exactly opposite to uncoated substrate [15].

The solvents have a significant impact on the accuracy of the structures. The flexographic printing plate material must adapt to the solvents in functional fluids to avoid plate swelling due to penetration of solvents in plate [16].

The solvents used in flexographic ink play an important role in printed

dot reproduction of both coated and uncoated paper. The dot shape improves with ink having high boiling point solvent and low drying velocity than the ink with low boiling point solvent and high drying velocity [17].

The ink transfer in flexography is governed by the substrate manufacturing processes. The correlation between substrate surface energy and ink surface tension have an impact on ink transfer. The surface treatments increase surface energy of the substrate that reduces the contact angle and improve wettability. The liquids adhere stronger to a surface with high surface energy [18].

The films with higher surface free energy results in higher optical density. A stronger adhesion leads to thicker layer of ink and hence higher optical density.

The optical density is greatly affected by polar component of surface energy in water-diluted

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inks and dispersive component of free surface energy in solvent based inks [19]. The substrate with lower surface energy reduces wettability and results in higher mottle [20].

The non-uniform corona treatment will result in improper wetting on the printing surface and lead to occurrence of uncovered areas in the print [21]. The dot gain is affected by the nip pressure between plate and impression cylinder.

The dot size increases with an increase in line screen [22]. The increased plate to substrate engagement results in reduction in L* values while higher anilox to plate pressure yields higher ink transfer in the mid-tone areas. The rise in press speed initially produces a drop in ink transfer but increases with further increased speed, particularly in the highlights [23]. The type of flexo plate-making has an impact on print quality. The digital platemaking shows signifi-

cant improvement in print contrast and tonal values as compared to conventional photopolymer plate [24]. The increase in depth of dot, increases dot stability that results in reduced tone value increase. The dot is expanded with an engagement of printing cylinder and impression cylinder. The line rulings on plate affects the image quality if not compensated during prepress [25].

Substrate-ink interaction The substrate surface energy, ink surface tension and interfacial tension between substrate and ink dictates the printability in flexography.

Surface energy substrate

of

The measure of break up of inter-molecular bonds occurring at the surface is referred to as surface energy. In simple terms, it is the energy required per unit area to increase the size

of surface and measured in mN/m. In the most basic sense, surface free energy is defined as the adhesive characteristic of the solid, indicating its affinity towards the other materials. The substrate surface energy and ink surface tension are the crucial factors in ink transfer, spreading and adhesion. The difference between the surface energy and the surface tension has larger impact on ink transfer and extent of spreading.

Higher the difference lower will be contact angle and better is the ink spreading on the substrate.

Nevertheless, very high surface energy may lead to erratic print quality. Surface free energy can be calculated by contact angle measurement with certain liquids of known surface tension. Contact angle is the angle between a liquid surface and the outline of contact surface of solid.

The contact angle of a drop of liquid over a solid surface is determined

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by Young’s Equation.

Young described the relation between surface energy of solids, surface tension of liquid and their interfacial surface tension. It is mathematically given by: ฀฀฀฀=(฀฀−฀฀฀)/ ฀฀ (1)

Where θ = contact angle of liquid γs = Surface Energy of Solid γL = Surface Tension of Liquid

contact angle lower will The above equation was be the wettability. replaced by simplified Young’s Equation to calTwo types of PE subculate the surface enerstrates were selected gy from the contact anfor the work having an gle. average opacity of 79% and 82%. The surface ฀ ฀(1+฀ ฀ ฀ ฀)= 2 energy of these sub- [√฀฀฀฀฀฀+√฀฀฀ strates were determined ฀฀฀ (3) by measuring the conWhere tact angle of two test liquids viz., Formamide ฀฀฀=฀฀฀฀฀฀฀฀ and Glycerol of known ฀฀ ฀฀฀฀฀฀฀฀฀ polar and dispersive ฀฀ ฀฀฀฀฀ components.

Holmarc Contact Angle Meter ฀฀฀=฀฀฀฀฀฀฀฀ was used to measure ฀฀ ฀฀฀฀฀฀฀฀฀ contact angle on both ฀฀ ฀฀฀฀฀฀ the substrates with 10 ฀ ฀ ฀=฀ ฀ ฀ ฀ ฀ samples each. ฀฀฀฀฀฀฀฀฀ ฀฀

γSL = Interfacial Surface Tension between The geometric mean equation was used to Solid and Liquid calculate the surface The contact angle can energy of these subbe measured by either strates. by varying the drop vol฀ ฀+฀ ฀−2 ume or with constant ฀ ฀ ฀= drop volume. The fac- (√฀฀฀฀฀฀+√฀฀฀ tors that affect contact ฀฀฀ (2) angle other than sub- γs = Surface Energy of strate surface energy Solid are ink surface tension, its viscosity and wetting γL = Surface Tension of speed. The contact an- Liquid gle determines liquid’s γSL = Interfacial Surwettability on that surface Tension between face. Thus higher the Solid and Liquid

฀฀฀฀฀

฀ ฀ ฀= ฀฀฀฀฀ ฀฀฀฀฀฀฀฀฀ ฀฀ ฀฀฀฀฀฀ ฀฀฀ of Formamide = 39.5 ฀฀฀ of Formamide = 18.7 ฀฀฀ of Glycerol = 34 ฀฀฀ of Glycerol = 30 γL of Formamide = 58.2 γL of Glycerol = 64 Substrate 1

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58.2(1+cos67.51)=2 Therefore, total Surface ฀= Force acting on the [√39.5×γsd + √18.7 Energy of PE laminate plate ×γsp] (4) for Substrate 2 ฀=Surface tension of 64(1+cos80.78)=2 = γsd+ γsp=40.7 mN/m liquid (ink) [√34×γsd + √30 ×γsp] Substrate 1 and Sub฀= Wetted perimeter of (5) strate 2 are different in the plate only opacity. The opaciSolving equation (4) ty of substrate was var- ฀= Contact angle with and (5), polar and disied to check it’s effect plate persive components of on print attributes. Both substrate 1 was calcuthe substrates are 40 μ Surface tension measlated thickness (37 GSM) with urement was conducted on 10 samples of ink to γsd=42.05 and 0.943 density. The gloss of the substrates was increase accuracy of γsp=0.0225 The 65% @ 600. The Coeffi- measurement.

Therefore, Total Surface cient of Friction (CoF) mean surface tension found to be Energy of PE laminate was ranging between was for Substrate 1 0.3 to 0.4 while Haze 23.98mN/m at 220C. The temperature is a = γsd+ γsp=42.26 mN/ between 10% to 15%. crucial factor affecting m The contact angle was surface tension. The rise found to be lower at 20 in temperature exerts Substrate 2 sec viscosity (Table 1), more molecular vibra58.2(1+฀ ฀ ฀68.6)=2 thereby resulting in tions among the liquid [√39.5×฀฀฀ + √18.7 higher ink spread and molecules, thereby de×฀฀฀] print mottle (Figure 2). creasing surface ten64(1+฀ ฀ ฀81.48)=2 Surface Tension is de- sion. The increase in [√34×฀฀฀ + √30 fined as the amount of temperature, increases adhesion and decreases ×฀฀฀] (7) energy required to inthe cohesive forces becrease the surface of The polar and dispersive tween liquid molecules. the liquid by unit area. component of Substrate This results in increased The surface tension was 2 was hence calculated contact angle and redetermined based on by solving equation (6) duced surface tension.

Wilhelmy Plate method and (7).

The ink-substrate inter[26]. action is critical to print γsd=40.70 and ฀=฀฀ ฀฀฀฀ (8) quality. The ink layγsp=0.00722 down over the substrate Where, after transfer from the

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plate has an impact on printability.

The ink spreading depends on various printability factors such as circularity, area and perimeter of the dot. Moreover, it reflects directly on print defects such as voids and print mottle. A higher spreading tendency of ink over the substrate leads to better area coverage, reducing void area. On the contrary, spreading yields in scattered distribution of pigment particles with uneven reflectance from the printed substrate, thus leading to higher print mottle over non-absorbent substrates. NC based ink was prepared in a dispenser that comprised of Master Batch, Varnish/Resin, Medium and Solvent. Master Batch is a combination of Pigment, Additives, Varnish and True Solvent (Table 2).

following formulae: γsl = γs−γl(Cosθ) (9) S= γs -γl -γsl (10) where θ = Contact angle of ink with substrate.

The values of contact angle from Table 3 suggest higher spreading at lower ink viscosity (20 sec) for both the substrates. The higher surface energy of substrate 1 increases the ability of the substrate to bind with ink. Higher surface energy ensures higher spreading as the amount of spreading is

directly proportional to the difference in substrate surface energy of substrate and ink surface tension. This difference is found to be greater in substrate 1 and hence the ink spread is more in substrate 1 than substrate 2.

Furthermore, the lower contact angle at lower viscosity resulted in higher ink spread and print mottle. A higher adhesion between the ink and substrate is achieved on substrate 1 as indicated by higher work of adhesion (wa).

The negative values of

The interfacial tension (γsl), work of adhesion (Wa) and spreading coefficient (S) was calculated using

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spreading co-efficient (S) suggest that the spreading does not occur spontaneously. Substrate 2 displayed lower ink spread indicated by higher magnitude of S. Thus, 20 sec ink viscosity on substrate 1 resulted in higher ink spread.

Printability analysis Printability is essential for defining the optimum settings for improving print quality in flexography printing press. Printability in this study is defined as the optimal amalgamation of ink, substrate and process parameters for the responses such as ink gsm (grams per square meter), ΔE*00 and print mottle. The optimization of these responses with minimized defects shall enhance printability and reduce the overall manufacturing cost of a package.

the study. The plate layout design comprised of logo, solid and halftone patch, surface and reverse text. The solid patch was included to measure and analyze Ink GSM, ΔE*00 and Print Mottle. The halftone patch was used to check the tone value increase. The logo was incorporated in the layout for visual assessment while surface and reverse text to check minimum reproducible text.

These plates were mounted on the same sleeve and printing was carried out by keeping the other color parameters constant.

The dot circularity also referred to as roundness and represented as ฀=4฀฀฀2 (11) where A = area of dot and P = perimeter or the dot The ideal dot circularity is 1 and more closer to

Plate dot structure Two plates, with dot structure 1 (circular) and dot structure 2 (square) were used for

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1, better is the dot reproduction. The dot circularity of Dot Shape 1 (0.8194) was found to be higher than Dot Shape 2 (0.8163) as indicated by Figure 3.

Baseline tion

identifica-

A production run was conducted on 40μ PE substrate with solvent based blue ink at 23s ink viscosity (300C and 50% humidity) as measured by B4 Ford cup and diluted with npropanol and n-propyl acetate in the ratio of 4:1. A anilox cell volume of 5.3 billion cubic microns (BCM), square dot plate and 79% average substrate opacity was used for the run.

The other constant parameters set during the press run were 5.83 m/ s press speed, 1.7 mm plate thickness, medium backing tape with 0.38 mm thickness and 300 reverse angle chambered doctor blade. The assessment of response Ink GSM, Color Devia-

tion (ΔE*00) and Print Mottle was done with 20 printed sheets being considered as sample size for each response.

The baseline for Ink GSM and Print Mottle was the mean value of the sample size. The baseline or reference L*a*b* values for the blue color was 14.42L* 36.22a* -66.53b* and the target was set to reduce the color deviation from the baseline for the printed blue sample

with ΔE*00 not exceeding 1.5 (Table 4).

The selection of anilox roller cell volume was based on ratio of plate to anilox screen ruling and the available inventory used in daily production run. The plate to anilox screen ruling was kept in a range of 1:5 (5.3 BCM) and 1:7 (4.5 BCM) with plate screen ruling as 133 lpi while anilox screen rul-

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ing as 648 lpi and 914 are only two types of lpi. dot shape available round and square, A general full factorial hence considered. The experimental design recommended substrate was run with 4 factors opacity for the diaper namely viscosity with 3 application is normally levels while anilox volranging between 80% ume, dot shape and to 82%. The substrate substrate opacity at 2opacity below 79% will levels and 2 replicates, result in dispersion lines thus totaling to 48 runs on PE substrate while (Table 5). The dot shape opacity above 82% will 1 refers to dot circularirequire more addition of ty of 0.8194 while dot master-batch, thereby shape 2 refers to dot increasing the produccircularity of 0.8163. tion cost. Hence, the The lower level of subtwo opacity levels of strate opacity repre79% and 82% were sents mean opacity of considered for the work.

79% while higher level represents mean opaci- Ink GSM ty of 82%. The selection Ink GSM is the amount of levels for the factors of ink deposited over in DOE were considered based on the working levels. A viscosity lower than 20 sec will result in more tone value increase and mottling while viscosity above 24 sec will clog the anilox cells and yield in uneven lay down of an ink.

Anilox volume levels were considered based on ratio of plate to anilox line screen. There

one square meter of printed substrate. The Ink GSM was measured on solid patch of the printed sample.

The main effect plot (Figure 4) shows that higher ink GSM is obtained at higher viscosity (24 sec) and anilox volume (5.3 BCM) with a circular dot (dot shape 1) on lower substrate opacity. The solid content in the ink is higher at 24 sec viscosity that constitutes higher ink GSM. The anilox volume determines the quantity of ink transfer to the plate and further on to the substrate. Higher the anilox volume, higher the amount of ink de-

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posited and therefore the ink GSM. The larger area coverage on plate with dot shape 1 (circular dot) led to higher ink transfer and ink GSM. The difference between substrate surface energy and ink surface tension played a significant role in ink transfer. The substrate 1 with higher surface energy showed higher difference that led to more ink transfer. A higher surface energy increases the force of adhesion between the ink and the substrate. This force of adhesion pulls more ink from the plate and hence results in a higher ink GSM. There is no strong interaction between the factors affecting ink GSM (Figure 5). High ink GSM is obtained when an ink having 24 sec viscosity is used irrespective of the plates, anilox volume and substrate used. Similarly anilox volume of 5.3 BCM, dot shape-1 and substrate opacity-1

yielded maximum ink GSM. Minitab 17 was used to calculate ANOVA (Analysis of Variance) and Regression models for Ink GSM, ΔE and Print Mottle.

The degrees of freedom abbreviated as df (Table 6) are the number of values that can be varied once certain parameters have been established.

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Adjusted Sum of Squares (Adj SS) are measures of variation for different components of the model.

Sum of Squares describe the variation due to different sources. Adjusted Mean Square (Adj MS) measures the description of magnitude of variation by the term or model. Adj MS takes into consideration df. The F-value is the test statistic used to determine whether the term is associated with the response. It is the ratio of two sample variances i.e. MS of a particular row divided by MS Error. The p-value is the probability that measures the evidence against the null hypothesis. The lower p-values provide the stronger evidence against null hypothesis. The constants of the regression equation was derived from the coefficients of each term namely Viscosity, Anilox Volume, Dot Shape, Substrate Opacity and interactions between them.

The p-values in ANOVA (Table 6) of all the main factors are below α value of 0.05, thereby indicating as significant factors affecting Ink GSM. The lower p-values below α value of 0.05 proves rejection of null hypothesis. The viscosity was found to be of highest significance af-

fecting Ink GSM as indicated by higher F-value.

A 99.74% of variability could be explained by the model as indicated

by R-Sq. value. The adjusted R-Sq of 99.70% shows significant improvement of the model with selected four factors. As the experimental design involved

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2 replicates i.e. having multiple observations with an identical X values, hence lack-of-fit test was performed. The p-value greater than α>0.05 indicates that model correctly specifies the relationship between the response and predictors and the test does not detect lack-offit. The model was adequate as the lack of fit (p=0.568) value was greater than α > 0.05.

Print density The print density is directly correlated to ink GSM and therefore the trend for Ink GSM and print density is same as indicated by Main Effect Plot.

The main effects plot (Figure 6) shows that higher print density is obtained at higher viscosity, higher anilox volume, a circular dot shape and on a surface with lower opacity. A lower viscosity (20 sec) implies a lower concentration of solid content and hence a lower print

density was achieved. A lower anilox volume (4.5 BCM) resulted in a lower print density. This occurred due to the fact that a lower anilox volume will store a less amount of ink and

therefore will transfer lesser ink and hence a low print density. The dot shape 1 i.e. circular dots exhibited higher print density than square dotted plate.

This can be attributed to

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the fact that area coverage of circular dot is more than square dot (dot shape 2) and transfers more ink as compared to a square dot. The substrate 1 with lower mean opacity of 79% displayed a higher print density than substrate 2 i.e. mean opacity of 82.4%.

A higher ink transfer was observed at lower substrate opacity 1 due to higher surface energy of 42.26mN/m as compared to higher substrate opacity with a lower surface energy of 40.7mN/m that has led to higher print density.

The interaction plot for density (Figure 7) shows higher density at 24s viscosity, 5.3 BCM anilox volume for a circular dot shape at lower substrate opacity. The interaction of viscosity with anilox volume, dot shape and substrate opacity affects the print density. The higher solid content at 24 sec ink viscosity and more ink carrying capacity of 5.3 BCM anilox volume re-

sulted in high ink deposition on to the substrate; thereby higher print density. The higher area coverage of plate dot 1 and higher viscosity of 24 sec with less ink spread yielded in higher ink film thickness, thus higher print density. The ink with higher viscosity, high anilox BCM and circular dots yield high print densities. The interaction plot shows great inter dependence of circular dots with anilox volume. A sharp rise in print density was observed with circular dots at 4.5 BCM anilox volume as compared to square dots. The higher ink transfer at lower substrate opacity with higher surface energy was achieved at 24 sec ink viscosity.

color co-ordinates namely L*, a* and b*.

The L* refers to lightness and darkness of a color. The a* refers to green and red coordinates while yellow and blue coordinates are represented by b* values. Δ฀2000=√(Δ฀′ ฀ ฀ ฀ ฀)2+(Δ฀′ ฀ ฀ ฀ ฀)2+(Δ฀′ ฀ ฀ ฀ ฀)2+฀ ฀(Δ฀′ ฀฀฀฀)(Δ฀′฀฀฀฀)

Delta E

SL = 1 + 0.015(L′−50) 2√20+(L′−50)2 SC=1+0.045C′, SH=1+0.015C′T Δθ = 30exp{−(H′−275°25)2} RC = √C′7C′7+252, RT=−RC sin(2Δθ) KL = 1 default, KC = 1 default, KH = 1 default

The color variation or deviation in the print is referred to as Delta E. It involves a 3 dimensional color space where each color occupies unique location according to its

(13) Where, L′ = (L1 + L2)/2 C1 = √฀12+฀12, C2 = √฀22+฀22 C = (C1 + C2)/2 G = 12 (1−√฀−7฀−7+ 257) ฀1′ = a1(1 + G), ฀2′ = a2(1 + G) C1' = √฀1′+฀12 , C2' = √฀2′+฀22 C′ = (฀1′+ ฀2′)/2 ΔL′ = L2 − L1, ΔC′ = C2' − C1' ΔH′= √C1'C2'2 sin(Δh′/2)

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The color values of 14.42L* 36.22a* 66.53b* was considered as reference based on the customer approval.

The color deviation was calculated based on CIE ΔE2000 (weighing factor 1:1:1) with M1 measurement mode, D50 illuminant and 20 observer angle between reference L*a*b* and L*a*b* values of printed samples measured on the solid patches.

The Main Effect plot (Figure 9), depicts lower delta E at higher viscosity and anilox volume with square dot on higher substrate opacity.

The plot (Figure 10) indicates an interaction of viscosity with anilox vol- 5.005AniloxVolume ume and dot shape and (BCM) + anilox volume with dot 22.753DotShape (14) shape affecting ΔE*00.

The constants of the reRegression Equation for gression equation were ΔE*00 derived from the coefficients of each factor ΔE2000 = 9.57 and their interactions 1.792Viscosity(sec)with each other. The 0.53AniloxVolume(BCM) ANOVA Table (Table 7) + 22.753DotShape shows that all the main effects and interaction + 0.3477Viscosity*AniloxV of viscosity with anilox volume, dot shape and olume

anilox volume with dot shape as significant factors affecting Delta E. Dot shape was had a influential role in minimizing Delta E. The model summary indicates 97.20% of variability explained by the model while 96.8% adjusted R -Sq implies significant improvement of the model by using four factors. The lack of fit with

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p value of 0.051 represents the accuracy of the model.

Print mottle Print Mottle is defined as the undulations present on the surface of substrate.

Verity IA Print Target v3 software with Stochastic Frequency Distribution Analysis (SFDA) algorithm was used to measure Mottle on the solid patch. The output result of this algorithm is an index, quantifying mottle. SFDA firstly determines the properties of the texture of the image and then calculates the spatial distribution of the texture. When the scanned image area in digital format is fed to SFDA for analysis, the entire image area is sampled into a regular pattern of continuous and adjoining larger target areas which are further sub-divided into smaller pixel targets (Figure 11). The larger targets are measured for two parameters stored in separate data-

bases simultaneously; one database stores the two-dimensional standard deviation (s) within the smaller target area while the second database stores the mean

luminance value (MTL) of the pixels present in the smaller target area that describes the overall visual impact of the analyzed larger target area. When an area of

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interest is selected within the scanned image, the s and MTL values are extracted from their databases and the mottle index for the respective area of interest is displayed as a result.

The standard deviation “s” is calculated as:

฀=√Σ(฀ ฀−฀ ฀ ฀)2฀ (15) Where, PL -Individual pixel luminance MTL -Mean luminance of the pixels in the target area n -Number of pixels in the target.

Mottle = K* (σs* Ms* The level of uniformity σm) (16) among the targets is inWhere, dicated by the degree of variation in the value of K -Scaling Factor, “s” while the uniformity in luminance is indicat- σs -Standard deviation ed by the variance of of s values “MTL”. σm -Standard deviation

for more accurate mottle measurement. For calculating the mottle index of the entire area of interest, spatial distribution of texture mottle is calculated between the larger targets, by the following formula:

The mottle of the larger of MTL values target is then calculated Ms -Mean of “s” values SpatialMottle = K* (σo* Mo) (17) using the following forThe variation in the texmula. ture of image also needs to be calculated

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σO = Standard deviation of large target mottle number MO = Mean of large target mottle number The Print Mottle was measured on solid patch of the printed sample.

The solid print mottle was minimized at higher level of viscosity (24 sec), anilox volume (5.3 BCM), substrate opacity and lower level of dot shape (Figure 12). The higher ink spreading at lower viscosity (20 sec) due to higher spreading coefficient of ink results in uneven ink deposition on the substrate, thereby leading to higher print mottle.

The even lay down of ink on the substrate at higher viscosity (24 sec) reproduces good dot circularity, thereby resulting in lower print mottle. Too higher viscosity will result in higher print mottle due anilox cell clogging. The outcome of this result will be uneven deposition of ink on the substrate. The

print mottle was reduced at higher anilox volume and circular dot (dot shape 1) due to higher and uniform ink film deposition. Though the print mottle was minimized with higher

opacity substrate but the difference between both the substrate was negligible. This is because of lower surface energy of substrate 2 that led to less ink

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spread as compared to substrate 1.

The interaction plot (Figure 13) shows lower solid mottle at 24 sec viscosity, 5.3 BCM anilox volume with a circular dot on 82% mean substrate opacity.

The interaction of lower anilox volume and lower viscosity yields a high mottle index. The higher solvent content at lower viscosity (20 sec) with lower anilox volume (4.5 BCM) results in uneven ink deposition on to the substrate, thereby higher print mottle.

The lower dot circularity at lower viscosity with square dot leads to uneven distribution of ink on the substrate, thereby resulting in higher solid mottle. There was no significant interaction of substrate opacity with other factors and hence was not responsible for any change in solid mottle.

Regression Equation for Print Mottle

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Print Mottle = 0.3250 + 0.00875Viscosity(sec) 0.0073AniloxVolume (BCM) + 2.5384DotShape 0.05188Viscosity* DotShape - 0.23438AniloxVolume* DotShape (18) The regression constants were derived from the coefficients of factors Viscosity, Anilox Volume, Dot Shape and the interactions of Dot Shape with Viscosity and Anilox Volume. Table 8 indicates that viscosity, anilox volume and dot shape along with their interactions have significant effect on minimizing print mottle. The lack of fit with p value of 0.247 represents model adequacy.

The regression equations for Ink GSM, Delta E and Print Mottle were validated by conducting additional runs. The data between Actual and Predicted runs showed R2 value of 0.9242, 0.9372 and 0.9226 for

Ink GSM, Delta E and Print Mottle respectively; hence justifying the predictive ability of the models.

Response tion

optimiza-

The paramount settings for all the print attributes were optimized from the trials conducted as per the experimental design through response optimizer to identify the set of variables for multiple re-

sponses. The optimal settings for a single response are evaluated by individual desirability while composite desirability for multiple responses in the range of zero to one. The individual desirability will be 1 if the predicted response is closer to the target. The combination of individual desirability is calculated into an overall value as composite desirability for multiple responses. The

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higher the composite desirability value, the better the product quality. The response optimizer provides the "best" combination of variable settings as the global solution. The goal was set to minimize the response such as print mottle, ink GSM, and delta E. The composite desirability was estimated at different levels of anilox cell volume (BCM), viscosity, dot shape, and substrate opacity to identify the sweet spot between parameters fulfilling the Ui = highest acceptable The optimization plot goal. value for ith response (Figure 14) revealed global solution as 22 The desirability to mini- di = desirability for ith viscosity, 5.3 BCM mize a response is cal- response anilox volume, dot culated as below.

Individual Desirability = shape 2 (square) having di = 0 (฀i > Ui) (19) (Upper value – Predict- 82% substrate opacity ed response)/(Upper (2) with 0.9726 compodi = ((Ui - ฀i)/(Ui - Ti)) site desirability for minivalue – Target) ri (yTi < ฀i < Ui) (20) mization of Ink GSM, Composite Desirability, Delta E and Print Mottle di = 1 (฀i < Ti) (21) D = (d1 * d2 * …* dn) on 40μ PE film.

Where, 1/n (22) The optimized settings ฀i = predicted value of with 22 sec viscosity, Where ith response 5.3 BCM anilox cell voln = number of respons- ume, dot shape 2 Ti = target value for ith es (square dot) and 82% response substrate opacity was D = Composite Desirarun and average data of bility

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20 printed sheets was having mean opacity of considered.

79% and 82%. The analysis of the data was The area of one repeat assessed by main efof the job was 0.23 m2 fects, interaction plot and accommodates 113 and ANOVA to deterrepeats/prints in a Kg. mine the best combinaAn Ink GSM of 0.98 was tion of flexo process paachieved during the rameters enhancing production run while printability.

Further0.80 for optimized run. more, regression modThe ink consumption els were generated for per 0.23 m2 for producthe output response Ink tion run was 0.23 gm GSM, Delta E, Print while 0.19 gm for optiMottle and validated. mized run. Table 10 The validation runs for shows minimization in Ink GSM, Delta E and ink consumption by Print Mottle revealed 18.26% at optimized good predictive ability run of 22s viscosity and of the models with R2 5.3 BCM anilox volume value of 0.9242, 0.9372 with square dot plate and 0.9226 respectively. (dot shape 2) on 40μ PE The results revealed film a substrate having that ink viscosity, anilox mean opacity 82% volume, dot shape and (substrate opacity 2). substrate opacity were significant factors afConclusion fecting the response.

A general full factorial The other factors such DOE was designed to as a press speed, plate optimize flexo process type, plate thickness, parameters. The pro- backing tape, doctor cess parameters consid- blade angle will also ered for experimenta- have a significant imtion were anilox volume pact on ink transfer, (BCM) and dot shape at thereby affecting the retwo levels while ink vis- sponses. The Response cosity at three levels for Optimizer revealed the both the substrates optimized settings as 22

sec viscosity, 5.3 BCM anilox cell volume, dot shape 2 (square dot) and 82% mean substrate opacity on 40μ polyethylene film. However, the same methodology can be applied for other inks to validate the results for optimization and ink consumption. The optimal settings minimized the ink consumption by 18.26% while maintaining the desired ΔE*00 and reduction in overall manufacturing cost of a package.

Acknowledgments The author would like to thank Parakh Flexipacks and Windmöller & Hölscher India Private Limited for their infrastructure and financial support.

References

[1] Mordor Intelligence Report (2020). Flexible Plastic Packaging Market

by Type (Pouches, Rollstocks, Bags, Wraps), Material (Plastic & Aluminum Foil), Application (Food, Beverage, Phar-

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ma & Healthcare, Personal care & Cosmetics), Technology, and Region - Global Forecast to 2025 [online]. Available from: https:// www.marketsandmarket s.com/Market-Reports/ flexible-packagingmarket-1271.html.

[Accessed 20 May 2021].

[2] Indian Diaper Market (2016). India Diaper Market Overview, 2016 - Research and Markets [online]. Available from: http:// www.businesswire.com/ news/ home/20161128005918 /en/India-Diaper-Market -Overview-2016--Research. [Accessed 20 May 2021].

20right% 20engraving_Converting%20Q% 204thQrtr2011.pdf.

[Accessed 20 May 2021].

[5] Ardent D. (2006).

Ink Mileage: Measure & Manage [online]. Available from: http:// www.pffc-online.com/ processmanagement/5017paper-ink-mileagemeasure. [Accessed 20 May 2021].

[6] Rastetter J., & Bingham J. (2016). Lower Your Anilox Line Screen and Cell Volume for Better Performance FlexoGlobal [online]. Available from: http:// www.flexoglobal.com/ blog/2016/08/01/ [3] Kipphan, H. (2001). pamarco-lower-aniloxHandbook of Print Me- line-screen-celldia.

Springer-Verlag, volume/. [Accessed 20 Heidelberg, Berlin.

May 2021].

[4] Rogers A. (2011).

Choosing the right anilox-roll engraving for the application [online].

Available from: http:// www.harperimage.com/ media/downloads/ Choosing%20the%

20FLEXO%20Feb% 202010.pdf. [Accessed 22 May 2021].

[8] Teufler S. (2015).

Anilox Rollers - Choosing the Right Lineature [online]. Available from: http:// www.harperimage.com/ media/downloads/ Anilox% 20Rollers_Choosing% 20The%20Right% 20Lineature_Flexible% 20Packaging% 20Issue%201.pdf.

[Accessed 22 May 2021].

[9] Hogan P. (2018).

Aniloxes - Yesterday, Today and Tomorrow [online]. Available from: http:// www.harperimage.com/ media/downloads/ Aniloxes_Yesterday% 20Today%20and% 20Tomorrow_% 20L&NW%20NovDec% 202018.pdf. [Accessed [7] Teufler S. (2010).

22 May 2021].

Weighing Your Coating Options [online]. Availa- [10] Harper C. (2005). ble from: http:// Do you know what ink www.harperimage.com/ film thickness is transmedia/downloads/ ferred [online]. AvailaWeighing%20Your% ble from: http:// 20Coating%20Options% www.harperimage.com/

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media/downloads/ Harper_FGA_1_2005.pdf.

[Accessed 22 May 2021].

[11] Green C. (2013).

Understanding Common Flexo Print Defects Part 2 FlexoGlobal [online]. Available from: http:// www.flexoglobal.com/ blog/tag/anilox/ page/4/. [Accessed 22 May 2021].

[12] Poulson B. & Hudson K. (2010). Correlating Ink Labs Drawdown to Press [online]. Available from: www.harperimage.com/ media/downloads/ Radtech%20Report% 20Sep-Oct% 202010.pdf. [Accessed 24 May 2021].

[13] Harnandez R. (2019). Releasing the Anilox’s Power [online].

Available from: http:// www.harperimage.com/ media/downloads/ Releasing%20Anilox% 20Power_FLEXO% 20Jan%202019.pdf.

[Accessed 2021].

24

May [18] Hizir, F.E., & Hardt, D.E. (2014). Effect of Substrate Contact Angle [14] Olson, R., Yang, L. on Ink Transfer in FlexoStam J. V., & Lesrelius, graphic Printing M. (2006). Effects of ink [online]. Available from: setting flexographic http:// printing: Coating polariwww.comsol.co.in/ ty and dot gain. Nordic paper/ Pulp and Paper Redownload/194575/ search Journal, 21(5), hizir_paper.pdf.

569–574.

[Accessed 26 May [15] Gencoglu, E. N. 2021].

(2012). Influence of Ink [19] Izdebska, J., PodsiViscosity on Dot Gain adlo, H., & Hari, L. and Print Density in (2012). Influence of Flexography. Asian JourSurface Free Energy of nal of Chemistry, 24(5), Biodegradable Films on 1999–2002.

Optical Density of Ink [16] Theopold, A., Neu- Coated Fields of Prints. mann, J., Massfelder, D., Advances in Printing & Dörsam, E. (2012). and Media Technology, Effects of Solvents on 39, 245–252.

Flexographic Plates. Ad[20] Rong, X., & Keif, M. vances in Printing and (2007). A Study of PLA Media Technology, 39, Printability with Flexog159–168. raphy. The Technical As[17] Simseker, O. sociation of the Graphic (2011). Investigation of Arts, 3, 605–613.

Different Solvents in [21] Mesic, B., LesteFlexographic Printing lius, M., & Engstrom, G. Ink’s Effects to Print (2006). Influence of CoQuality on Coated and rona Treatment Decay Uncoated Paper. Asian on Print Quality in Water Journal of Chemistry, 23 -borne Flexographic (7), 2903–2906.

Printing of Low-density

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Polyethylene-coated Pa- of Engineering Manufacperboard.

Packaging ture, 218(11), 1499– Technology and Science, 1511.

19(2), 61–70.

[26] Ebnesajjad, S., & [22] Valdec, D., Zjakić, Landrock, A. (2015).

I., & Milković, M. Surface Tension and Its (2013). The Influence of Measurement. In: S. Variable Parameters of Ebnesajjad, 3rd ed. AdFlexographic Printing on hesives Technology Dot Geometry of Pre- Handbook. William Anprinted Printing Sub- drew, Elsevier Inc, 19– strate. Tehnički vjesnik, 29.

20(4), 659–667.

Akshay V. Joshi received [23] Claypole, T.C., Jew- Bachelor’s and Masters ell, E.H., & Bould, D.C. Degree in Printing Engi(2012). Effects of Flexo- neering from University graphic Press Parame- of Pune, India. He was ters on the Reproduc- awarded Ph.D. tion of Colour Images. (Engineering) from Advances in Printing Jadavpur University, and Media Technology, Kolkata in 2015. Dr. 39, 187–194.

Akshay Joshi is working as Assistant Professor, [24] Gilbert, D.E., & Printing Engineering DeLee, F. (2008). Flexopartment at P. V. G’s graphic Plate TechnoloCollege of Engineering & gy: Conventional SolTechnology and G. K. vent Plates Versus DigiPate (Wani) Institute of tal Solvent Plates. JourManagement, Pune, Innal of Industrial Techdia since 1996. He is nology, 24(3), 1–7.

Coordinator, Board of [25] Bould, D.C., Clay- Studies and Member, pole, T.C., & Bohan, Research and RecogniCommittee for M.F.J. (2004). An Inves- tion tigation into Plate De- Printing Technology at formation in Flexo- Savitribai Phule Pune graphic Printing. Journal University. His area of

research is Gravure, Flexo and Flexible Packaging. Dr. Akshay Joshi has published several papers in Journals and guided candidates for Master Program in Printing Engineering and evaluated Ph.D. candidates. He is been internationally qualified as G7 Expert by Idealliance USA and implemented first G7 calibration for Gravure and Flexography printing processes in India. He is a Life Member of Indian Society for Technical Education. http:// orcid.org/0000-00028733-1747

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The Future of Package Printing to 2027 This report covers the print for packaging market over the period 2017– 2027. It explores the restraining factors in play, including the increasing demand for more sustainable packaging; this will alter patterns of demand between packaging materials, as well as restraining overall demand in the market to some extent.

In 2022, the package printing market was estimated to be worth $473.7 billion; this will reach $551.3 billion by 2027 (constant 2021 prices), with a growth rate of 3.1%. Flexo is the largest process when it comes to package printing in 2022 and remains the largest to 2027, growing at a rate of 2.4%. Globally, corrugated & cartons is the largest material segment and will remain so to 2027, growing at a rate of 3.3%.

This report covers the print for packaging market over the period 2017– 2027. It explores the restraining factors in play, including the increasing demand for more sustainable packaging; this will alter patterns of demand between packaging materials, as well as restraining overall demand in the market to some extent. The market will grow over the coming five years, underpinned by deeprooted drivers: global population increase, the

increasing rate of global urbanisation, the growing global middle-class consumers and the rising number of oneperson households, which drives demand for smaller pack sizes.

Our tent

exclusive

con-

The key areas of growth over the next five years and how a changing market place is affecting growth in the industry.

Comprehensive analysis of key market drivers and trends in

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the package printing more sustainable pack- Who should buy the remarket to 2027 aging. port?

The role of package printing in developing sustainable practices • In-depth market forecasts segmented by technological developments, printing process, materials, printing ink and geographic region.

What will you discover?

The impact of developing digitisation of the market and how this will affect output In the period 2022–27 digital print will be the fastest growing print technology area in print for packaging by both value and output The restraining factors in play, including the increasing demand for

The Smithers meth- Raw materials suppliers odology Packaging converters This report is based on extensive primary and secondary research. Primary research consisted of targeted interviews with material suppliers, converters and experts drawn from key markets. This was supported by secondary research in the form of extensive literature analysis of published data, official government statistics, domestic and international trade organisation data, company websites, industry reports, trade press articles, presentations, and attendance at trade events.

Package printers Equipment and machinery supplier Brand owners and retailers Industry consultant and analysts About the author Paul Ewing has over 20 years’ experience in the digital printing industry with ICI, Zeneca, Avecia and Fujifilm. He was VP of R&D and Business Strategy for Fujifilm Imaging Colorants, the speciality chemical arm of Fujifilm’s inkjet printing business.

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8th drupa Global Trends Report: Global print industry shows post Covid recovery and resilience in face of fresh challenges The 8th drupa Global Trends Report will be published in September 2022.

The first results from a survey conducted this spring are now available.

One important conclusion: overall, confidence is on the rise and all regions and markets forecast higher investment in 2023.

The results from the survey show an industry that is on average across the globe a little more confident for the future than when last surveyed in 2019, before the pandemic. The Packaging market is strongest, but Commercial, Publishing and Functional markets all show signs of recovery in 2023.

Regionally, confidence levels vary e.g. Asia and South America expect better trading in 2023 while Europe is downbeat given the Russia/Ukraine

war and quences.

its

conse- covery to start in 2023.

All regions and markets forecast higher investInvestment fell inevitament in the coming bly during the last two year.”

The findings years, but printers and come from the 8th suppliers both reported Global Trends online strong plans for capital survey, when over 500 expenditure.

Sabine senior decision makers Geldermann, Director on the part of print serPrint Technologies at vice providers and maMesse Düsseldorf, comchine manufacturers/ mented: “Printers and suppliers worldwide Suppliers know they completed an extended must innovate to sucsurvey in spring 2022. ceed in the longer term.

The survey was conThe shocks of the last ducted by the commistwo years pegged back sioned partners Printfuinvestment, but the ture (UK) and Wissler & survey indicates that Partner (Switzerland) the industry expects reon behalf of drupa.

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Confidence depends among Commercial on market and region printers matched by increases among PackagGlobally 18% more ing printers. Flexo volprinters described their umes continue to accelcompany’s economic erate for Packaging condition as ‘good’ comprinters, while all marpared with those that kets reported increased reported it as ‘poor’. For volumes using Digital suppliers the net positoner cutsheet colour tive balance was even and all but Publishing stronger at 32%. As alwith Digital inkjet rollfed ways, confidence varies colour. between regions and markets. The Packaging Despite the active demarket is thriving with cline in the volume of Publishing and Com- Sheetfed offset in Commercial facing structural mercial markets, this changes from digitisa- was the most popular tion but with signs of press type for investconfidence returning. ment in 2023 across all Regionally the picture is markets except Packagmixed with Europe ing, where Flexo led, clearly concerned about followed by Sheetfed the consequences of the offset. Digital toner cutRussia/Ukraine war but sheet colour was the others e.g., Asia and second most popular South/Central America, target for all other marexpect trade to pick up kets. Finishing equipfurther in 2023 as eco- ment is the second nomic momentum most popular target for builds post pandemic. investment after new presses.

Print volume and investment plans Web-to-Print Analysis of print volume in 2022 by press type, shows continuing decline in Sheetfed offset

While there was virtually no increase in the proportion of turnover won by Web-to-Print in-

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stallations between 2014 and 2019, over the last two years the proportion won by that means has shot up for those with such installations. Globally, since 2019 there has been an increase from 17% of turnover to 26% and this major increase is reflected to varying degrees across all markets.

Socio-economic pressures and the global economic market Socio-economic pressures are having a major impact across the globe, although they vary in influence between regions. For example, 62% of printers in Asia chose Pandemics as the biggest threat, while in Europe this was chosen by 51%. And while 32% of European printers chose Physical wars, this was chosen by only 6% of those in South/Central America.

Instead, 58% of them chose the threat of economic recession. Richard Gray, Operations Di-

rector at Printfuture, stated: “Socio-economic pressures are increasingly important to printers and suppliers alike, so much so that 59% thought these were now either as important or more important than print market pressures.”

by the end of September and available for sale from www.drupa.com.

The executive summary will be available for free in German, English, French, Portuguese, Spanish, Russian and Chinese.

The global economic market has experienced more shocks in the last two years than at any time since the Second World War. Yet this survey shows that print is still a central means of communication in all markets and regions and that while there are challenging times ahead, the industry has both the confidence and the determination to succeed. Wise strategic investment will ensure that printers and their suppliers will thrive.

drupa has been surveying international print service providers and suppliers since 2013 in order to shed light on industry and global megatrends, market potential and innovations in all key areas of the print industry. For further information on the drupa Global Trends Report and previously published editions (Executive Summaries), please click here: www.drupa.com/en/ Press/ Global_Trends_Reports

Infographics and obtaining the full reports Infographics showing the key findings are attached to this press release. The full report in English will be released

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Total Productive Maintenance Analysis on Printing Machine (A Case Study in an Indonesian Flexible Packaging Manufacturer) PT XYZ is one of Indonesia’s major flexible packaging manufacturer companies. The company suffers losses from the increase in printing machine breakdown from 1.65% in 2019 to 2.52% in 2021. This paper aims to reduce the breakdown duration in 2022 by identifying and solving the root cause by implementing one of the alternative solutions. The primary data are collected via a series of interviews and from the company’s manufacturing reports. Using Current Reality Tree (CRT) the root cause was identified as a lack of regular maintenance evaluation and improvement. The study proposes three alternative solutions: Planned Maintenance (PM), Autonomous Maintenance (AM), and condition-based maintenance using IoT sensors. In determining the preferred alternative, the study uses Analytic Hierarchy Process (AHP) with five criteria: OEE improvement, human capital improvement, Capex required, Opex required, and ease of implementation. Align with the AHP result, the company agreed to implement Planned Maintenance (PM). After the first two months of implementation, the average year-to-date breakdown in 2022 was reduced to 2.29%.

As the world’s fourth most populous nation, Indonesia has a large market for flexible packaging. The flexible packaging is primarily used for fast-moving consumer goods such

as foods, beverages, personal care, and home care. In terms of manufacturing cost, logistic cost, and carbon footprint, flexible packaging is intrinsically favored when compared

to other packaging formats.

For example, transporting 200 ml beverage glass bottles in crates equals carrying only 48% of the beverage by weight and the other 52% for the

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glass packaging. In contrast, by using flexible packaging, 94% of the weight carried can be occupied with the beverage while only 6% of the total weight is used for the packaging [1].

The flexible packaging manufacturing process in PT XYZ consists of three sequential processes: printing, laminating, and finishing.

The printing process has the lowest production capacity and it becomes the bottleneck of the whole production process.

The overall throughput of a production system is limited by the processing capacity of the bottleneck pro-

cess [2]. As a bottleneck, any unplanned downtime in the printing machine will cause a reduction in the company’s overall yield. Compared to the available time, the breakdown duration in the printing section in 2021 is 2.52%. Assuming that the breakdown in 2021 did not happen, the company would have been able to produce an additional 12 million running meters of finished goods throughout the year. The management of the company begins to raise their concern after the fact that the machine breakdown percentage in 2021 has increased to

more than 150% when compared to the number in 2019. The increase of breakdown frequency or the deterioration of Mean Time Between Failures (MTBF) can be an indicator to investigate the physical degradation mechanisms in action [3]. The company has implemented some measures of preventive maintenance; however, the increase in breakdown percentage in the printing section shows that the current strategy is ineffective. Therefore, the research is needed to find the root cause of the problem, propose an alternative solution, and evaluate

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the result of the imple- research uses a cyclic or mentation. spiral process which alternating between the The research is aimed diagnosing, action planto reduce the total ning, action taking, breakdown of the two evaluating, and specifyprinting machines in the ing learning.

West Java Plant. The actions will emphasize the The diagnosing step beEngineering Depart- gins with stating the ment’s standpoint. business issue of the increasing machine METHODOLOGY breakdown between The action research 2019 and 2021. In evalmethodology is used to uating the current conget a higher level of dition of the company, practical relevance of the author uses a mixed the research and to gain -method between quanbetter understanding titative and qualitative about the actual prob- analysis using OEE data lem in the field. Action and series of interviews

with the stakeholders.

After the interview, undesirable effects (UDEs) are identified. The UDEs are then arranged into the Current Reality Tree (CRT) to identify the root cause of the business issue.

Once the root cause of the problem has been identified, the research continues with the action-planning step.

Three alternative solutions are prepared and among the three, the best alternative is proposed to the management of the company.

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To determine which solution is the most suitable to be implemented, the researcher compares the three alternatives in regards to OEE prediction, strengths and weaknesses comparison, and Analytic Hierarchy Process (AHP). The Engineering Manager, Production Manager, and Human Resource Manager of the company are chosen as respondents for AHP.

activities, namely office task and field task. The office task includes the preparation of maintenance task list, inspection checklist, breakdown analysis, and troubleshooting handbook. Whereas the field task covers the actual maintenance activities on the shop floor. Before the regular time-based maintenance, a restore basic condition is performed for each printing machine. In the next The action-taking step step, the effectiveness consists of two major

of the implementation is evaluated.

The two quantitative parameters used for the evaluation are breakdown rate and the OEE of the printing machines. Lastly, the learning outcome of the study is specified. The conclusion answers the research questions of the root cause, the selected solution, and the implementation result.

RESULT OEE or Overall Equipment Effectiveness is an

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effective tool to measure and analyze the efficiency of a single machine [4]. By analyzing the OEE, the information on the sources of lost production and lost time can be measured [5]. OEE is needed because a traditional productivity matrix (i.e. throughput and utilization rate) is not very helpful for identifying the fundamental problems and opportunities for productivity improvement in an organization [6]. OEE is calculated as the product of three contributing factors, availability, performance, and quality [4].

OEE = availability x per- 74.45% availability, formance x quality which is far lower compared to performance Analysing the 2021 and quality. manufacturing report provided by the compa- Machine breakdown is ny, the OEE of the print- among the unplanned ing section is calculated downtime that causes in Table 1. The OEE of the reduction in ma69.82% is fairly typical chine availability or time for manufacturers. How- efficiency. To identify ever, the ideal OEE for a the undesirable effects world-class manufactur- (UDEs) related to the er according to Nakaji- increase of machine ma is above 85% with breakdown in the printavailability, perfor- ing section, the authors mance, and quality conduct a series of inabove 90%, 95%, and terviews with the Engi99% respectively [4]. neering Manager, the Among the three varia- Preventive Maintenance bles, the company Planner, the Mainteneeds to prioritize im- nance Technician, the proving the existing Production Manager, the

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Printing Machine Operator, and the Human Resource Manager. By arranging the UDEs into the Current Reality Tree (CRT), the root cause of the problem is identified as a lack of regular maintenance evaluation and improvement.

tion speed and quality.

The next step is to create a time-based maintenance task list as

exemplified in Table 2.

The task list is created based on the machine manual book, the his-

After the root cause was identified, the authors come up with three alternative solutions. The first alternative, Planned Maintenance (PM), is one of the eight pillars of Nakajima’s TPM. PM pillar is a strategy to achieve the goal of zero breakdowns in TPM [7].

The pillar aims to reduce machine breakdown by fixing the equipment before its failure. The scheduling of the maintenance activities is based on the historical data of the machines, such as failure rates and breakdowns. The implementation is started by restoring the equipment to the basic condition to reinstate the machine back to its prime condition in terms of produc-

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torical breakdown data, and the Quality Plan of the printing process.

The maintenance task list has to be updated regularly based on the breakdown occurrences.

Maintenance intervals can also be adjusted to find the balance between machine reliability and maintenance cost. The planning of maintenance and top management commitment in conforming that maintenance is a core competence is necessary to sustain the competitive advantage of a company [8].

performing minor maintenance tasks on their machines. The implementation is started with the initial cleaning of the equipment by the operators and technicians. Fuguai or the machine abnormalities found during the initial cleaning are recorded to

be repaired by the technicians [9]. A red tag will be placed on the equipment to indicate the abnormality location and a work request to the Engineering Department will be made. After the initial cleaning, minor maintenance tasks such as cleaning,

The second alternative, Autonomous Maintenance (AM), is also taken from one of the TPM pillars. The pillar emphasizes machine operators’ involvement in

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inspection, lubrication, and tightening are performed regularly by the machine operators. By autonomously carrying out regular maintenance, the operators will develop the responsibility to ensure the equipment were able to achieve high productivity and quality [10]. Another advantage of transferring inspection activity from technicians to operators is that the operators are present and working with the machines every day, which makes the operators more aware of the subtle changes in their machines. By being able to detect abnormalities earlier, the technicians could have more time to fix the abnormalities before the equipment failure or machine breakdown happens.

of Things (IoT) has become widely adopted in production machines.

Multiple wireless sensors are now available in the market at more affordable prices. IoT technologies make it possible for machine-tomachine communication to acquire the machine condition data (e.g. vibration and temperature) in real-time. Accurate prediction of such failures using sensor da-

ta can prevent or reduce the breakdown of valuable assets [11].

The sensors can be installed on the equipment to send the realtime measurement to the company’s server to be analyzed. The collected data can be transformed into information for conditionbased maintenance to inform the technicians when the equipment

The third alternative is condition-based maintenance using IoT sensors. This alternative focuses on utilizing sensors to collect real-time data on equipment conditions. In the era of Industry 4.0, the Internet

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needs further nance activity.

mainte- ment means that the equipment will be replaced or maintained reWhen the alternatives gardless of the condiare compared, planned tion. The maintenance Maintenance offers the activity is also labormost benefit in reducing intensive and requires machine breakdown machine downtime evewith its comprehensive ry three months. task list. It also allows the company to con- Some Autonomous stantly evaluate and im- Maintenance (AM) activprove its maintenance ities are similar to strategy. Even though Planned Maintenance. the alternative possess- However, the activities es promising benefits, are mostly performed the Planned Mainte- by the printing machine nance is high on operat- operators instead of ing expenses for technicians. Transferring maintenance costs. the activities to the opTime-based replace- erators will increase the

participation of the operators in a collaborative effort in maintaining the equipment. Because the AM is performed every week, the machines are cleaner and abnormalities can be detected sooner compared with PM activities which are performed every three months. The most significant drawback of Autonomous Maintenance is that the activities occupy a significant portion of operators’ time and potentially disrupt operators’ focus on product quality. Some

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operators might resist the change because they believe that performing machine maintenance is the job of the Engineering Department and not theirs.

Intensive training, coaching, and supervision will be needed to grasp the effectiveness of Autonomous Maintenance.

The last alternative solution, condition-based maintenance using IoT sensors, is excellent in eliminating the subjective judgment on inspecting the machine’s condition. The machine condition is quantitatively measured by the vibration and temperature sensors. The operating cost is also the least compared with the previous two alternatives because of the condition-based approach. The technicians will only replace the part when the condition is abnormal. The solution, nonetheless, is only able to cover a lesser portion of the break-

down categories. Furthermore, the installation of sensors will require high Capex in the beginning. Because of the limited scope of the IoT sensors, the solution can only provide limited room for continuous improvement and evaluation.

To determine which alternative to be proposed to the company, the authors use Analytic Hierarchy Process (AHP) with the Engineering Manager, the Production Manager, and the Human Resource Manager as the respondents.

Each alternative is evaluated using a pair-wise comparison from the five criteria: OEE improvement, human cap-

ital improvement, Capex (capital expenditure) requirement, Opex (operating expenses) requirement, and ease of implementation. At the end of the analysis shown in Table 4, Planned Maintenance (PM) is determined as the most preferable alternative by the stakeholders with a 0.46 score.

Autonomous Maintenance (AM) comes second, while Condition-based maintenance using IoT sensors is deemed as the least preferable alternative. After a discussion with the stakeholders, the company agreed to implement Planned Maintenance (PM) in the printing section as a pilot project.

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The implementation was started with restore the basic condition of the two printing machines.

The Fuguai or abnormalities detected during the restore basic condition were recorded in the Abnormality List to be repaired by the maintenance technician.

The second step of the installation is to create a maintenance task list bases on the machine failure rate. From the three sources (i.e. manual book, historical breakdown data, and Quality Plan), the team collected 469 maintenance activities with intervals varying from every two months until every two years.

the printing section had been reduced from 2.52% to 2.29%. As shown in Table 5, the improvement of printing machine breakdown was not followed by the improvement of OEE. Although both availability and performance are improved, the quality is worsened, resulting in 0.04% changes in OEE. The deterioration in quality, however, was identified as an isolated case and does not have

any connections with the PM implementation.

DISCUSSION The reduction in average machine breakdown in 2022 indicates that there is an improvement after the implementation of Planned Maintenance. In his book, Nakajima explained that one of the PM pillar goals is to achieve zero breakdowns. He also emphasized that such a goal cannot be achieved

After the first two months of implementation, the breakdown in

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overnight [4]. The data after the implementation is in line with the statement of Nakajima.

Although as of March 2022 the company has not been able to achieve zero breakdowns, positive progress can already be observed.

Even so, the result of the study is generalized due to the limitation of the observation duration which is only three months. Longer observation is needed to get a better picture of the implementation result.

The result also confirms the statement from the previous research in another Indonesian flexible packaging manufacturer [12]. In the research, the authors conclude that the inconsistency in preventive maintenance implementation and lack of autonomous maintenance will lead to machine deterioration. The authors also highlighted that the improper machine condition will lead to not only machine break-

down but also a high re- Maintenance (QM) may jection rate that causes follow. a further decrease in CONCLUSION OEE. This research found that In another study from to reduce the machine one of the flexible packbreakdown, firstly, the aging manufacturers in root cause has to be Pakistan, Shehzad et al. identified. By using CRT, concluded that successa lack of maintenance ful implementation of evaluation and improve5S and TPM will result in ment is identified as the a significant reduction in root cause. The maintemechanical downtime. nance task list that had The study reported that not been updated since the OEE has improved the first installation of from 50% to 53%, indithe machine caused the cating an improvement breakdown to increase in productivity and imas the machine ages. provement in the quality of the product [13].

Secondly, the root cause has to be answered by The study provides inone of the alternative sight between Planned solutions. The study Maintenance implemenproposed three alternatation and the reduction tive solutions to be of machine breakdown. compared Planned The pilot project in the Maintenance (PM), Auprinting section can be tonomous Maintenance rolled out to the blow(AM), and conditioning, laminating, and finbased maintenance usishing section in the ing IoT sensors. AHP is company. After the imused to determine plementation of Planned which solution to be Maintenance, other pilproposed to the compalars of TPM such as Auny and the AHP result tonomous Maintenance shows that Planned (AM) and Quality Maintenance (PM) is the

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best alternative. Align with the AHP result, the company decided to implement PM for both printing machines.

Lastly, after the PM implementation, an improvement in breakdown duration in the printing section was observed.

The 2.52% breakdown was successfully reduced to 2.29% after the two months of PM implementation.

REFERENCES 1. Marrone, M. and Tamarindo, S. 2018.

Paving the sustainability journey: Flexible packaging between circular economy and resource efficiency. Journal of Applied Packaging Research. 10(2), 53-60.

2. Dirnberger, J. and Barkan, C. 2007. Lean railroading for improving railroad classification terminal performance: bottleneck management method.

Transportation Research Record. 1995(1), 52-61.

3. Realini, A. et al.

2001. Study of a 20 year old PV plant (MTBF project). In Proceedings of the 17th EUPVSEC, 447-450.

4. Nakajima S. 1988.

Introduction to Total Productive Maintenance.

Portland OR, USA: Productivity Press.

5.

Pintelon, L.M.A., Muchiri, P.N. 2008. Performance measurement using overall equipment effectiveness (OEE): Literature review and practical application discussion.

International Journal of Production Research. 46(13), 3517 -3535.

6. Huang, S.H., et al.

2003.

Manufacturing productivity improvement using effectiveness metrics and simulation analysis. International Journal of Production Research. 41(3), 513-527.

7. Kar, M.K. 2016. Implementation of Planned Maintenance using TPM methodology for a bicycle manufacturing in-

dustry.

International Journal of Mechanical Engineering and Technology (IJMET). 7(6), 253-270.

8.

JasiulewiczKaczmarek, M. 2016.

SWOT analysis for Planned Maintenance strategy-a case study.

IFAC-PapersOnLine. 49 (12), 674-679.

9. Gupta, A.K., Garg, R.K., 2012. Improvement by TPM Implementation: A Case Study.

International Journal of IT, Engineering and Applied Science Research (IJIEASR). 1 (1), 115-124.

10. Guariente, P., Antoniolli, I., Ferreira, L.P., Pereira, T., and Silva, F.J.G. 2017. Implementing autonomous maintenance in an automotive components manufacturer. Procedia Manufacturing. 13, 1128-1134.

11. Namuduri, S., Narayanan, B.N., Davuluru, V.S.P., Burton, L., and Bhansali, S. 2020. Deep learning methods for sensor based predictive

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maintenance and future perspectives for electrochemical sensors. Journal of The Electrochemical Society. 167(3), 037 -552.

12. Nugroho, T.S. and Nugroho, R.E. 2020.

Improvement of oil pack reject flexible packaging on printing, lamination and slitting processes (a case study in PT. XYZ).

Saudi Journal of Business and Management Studies. 99-111.

13. Shahzad, A., Zahoor, S., Sarfraz, S., and Shehab, E. 2018. Implementation of TPM in a process industry: a case study from Pakistan. Advances in Manufacturing Technology XXXII. 511-516.

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Standard Bag: A Not So Standard Story At Oregon-based Standard Bag, a 37-year-old family-run company, the addition of a brand new MIRAFLEX II is opening the door to new possibilities and opportunities.

The “The MIRAFLEX looks like a spaceship,” says Jerry Lin, son of founders Paul and Meiling Lin. “The press is reinvigorating our company.

It’s like we bought a Ferrari – a machine that’s meant to go fast, now we need to learn to maneuver it like a Formula 1 driver and push it to the extreme,” Lin added.

FLEX II will help them go after new business in flexible packaging and roll stock as well as from more branded customers.

produces multiwall paper, poly woven, and laminated paper bags.

Lin says the company has found their niche in higher-value multiwall bags “We’re big believers in a two-ply multiThe family describes wall bag,” said Lin, addthemselves as “bag ing that the bags are makers at heart” and incredibly strong.

The MIRAFLEX is part of a 5–10-year campaign to invest in equipment that will help retool and reinvigorate the company that’s being driven

by Jerry and his brother, George. The MIRA-

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Standard Bag and W&H, including subsidiary Garant, have known each other for decades with the original multiwall equipment as well as a printing press in Oregon coming from W&H. The Lin's story is an interesting one.

Their American life started out in California. Then Paul and Meiling paired up with a packaging broker and multiwall bag supplier in Oregon.

Within six months of arriving in Oregon, their business partner died, leaving the Lins standing with some equipment, a couple of em-

ployees and no salesperson.

That’s when Paul, with his broken English, started driving up and down Route 99, the Agricultural Beltway of California, knocking on doors at farms trying to get the company off the ground. It paid off; some of those first customers are still with them today, decades later. The company has grown, and even opened a second facility in Lubbock, TX – during the Great Recession, 14 years ago – to position themselves as a nationwide supplier of multiwall packaging.

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Comexi Enters the Digital Printing Sector With Its New Digiflex Press After nearly 70 years manufacturing capital goods for the flexible packaging converting industry, Comexi is taking a step forward: fully moving into digital technology. At K 2022, the company will present the Digiflex press, its first digital printing solution that enables the flexible packaging industry to meet the current needs of a changing and increasingly demanding market. The Digiflex will be the primary attraction at Comexi's Messe booth, 4B31, in Düsseldorf (Germany). From 19th to 26th October, during daily demonstrations, attendees will have the opportunity to view the Digiflex press in operation.

"The Comexi Digiflex is the machine that currently offers preeminent digital printing of variable data, such as Data-

matrix variable codes, QR codes, barcodes, alphanumeric text, as well as other numbering and marking applica-

tions with high quality requirements", explains Pedro Jiménez, the digital technical sales director at Comexi, who also

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highlights that "it is a digital variable data print press that offers extremely high printing speed, superb quality results, as well as the highest level of performance and production. Digiflex is an all-in-one solution that includes the integration of the curing process, tension control, printing registration, corona treatment, and a video inspection system."

material. A a digital press, the Digiflex is an efficient solution due to its ability to reduce set-up times.

It can reach a maximum speed of 220 m/min, reduce material waste, and improve lead time.

Furthermore, the machine offers high printing quality with a resolution of up to 1200x1200 dpi, a minimum code size of 8x8 mm, as well as printing and registration Comexi's new digiconsistency. tal press uses lowmigration inks that Different Codes are suitable for with Unique Infood packaging formation printing; it offers Using the Digiflex excellent results in allows for the regard to quality printing of variable tests (tape, ethadata such as QR nol, and scratch). codes, DOT codes, The machine alalphanumeric text, lows for the possivariable inforbility of doublemation, numbersided printing ing, barcodes, without treatment, Datamatrix or imas well as printing ages. Each printed on pre-printed

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code can be different and contain unique information, providing traceable material information, thus personalizing products according to the consumer’s needs, and protecting brands from counterfeiting. "The Digiflex codes tracks and traces each product, complying with legal requirements as well as contributing to the circular economy, serialization and security of the supply chain," says Jiménez, who emphasizes that this machine not only "helps boost customer awareness, brand loyalty, and feedback acquisition, but also enables the analysis of consumer behaviour. Finally, the Digiflex offers security, anti-counterfeiting, and authenticity solutions, which is highly valued by brand owners.”

type and performed production processes of each packaging unit, which makes recycling more appropriate and efficient.

Comexi participated with its Digiflex press in the R-Cycle project, led by the Reifenhäuser Group.

The unique codes of the press machine identify the plastic

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