Project Can Crusher “simply epic”
By Sina Fazel Start Date : 3-09-07 Finish Date : 11-03-08 153 days 8 hours 27 seconds
Summary Of Report The report is about designing an engineering project or improving and modifying a current design, in this case it is about designing a can crusher to promote recycling in routine life at a relatively cheap price. The report shows Initial ideas and designs for the can crusher and explanations of the problems that were encountered on the way and how they were overcome. At the end the report explains an evaluation and future goals to improve the current design.
Introduction In October the class was set a project, the project was basically to make/invent and improve a current engineering problem, we were all allowed to go home and think of our own separate ideas that would be suitable for the task. After consideration of a few ideas I decided to go with a can crusher, not many people have this instrument in there household yet it can be really cheap to buy or to make for that matter. We have been given a criteria sheet to follow which suggest showing our designs from sketches to British standard drawings, along the way I’ve written the problems that occurred when trying to make the can crusher and wrote how I have overcome them, inside is a final evaluation of my project which basically states how it performs and if I am satisfied with how it works and if so why or what I could improve. From this I hope to improve the recycling of aluminium cans.
Planning To start my project of I am going to draw simple sketches of my design ideas for my can crusher (see can crusher designs), from those designs I plan to choose the most appropriate design and draw that design with more detail whether it be detailed sketches or detail CAD drawings but before I can dimension my drawings I will have to measure a can and base my design around the size of the can, once doing this I can then implement dimensions and start to conduct technical drawings of which will contain each part of the can crusher. From this I can then start to make the can crusher in the workshop. Every two weeks I hope to make one part as we only have limited time in the workshop this may prove difficult especially if I encounter problems in my design. Once all the parts are complete I can then assemble it all together and test the device, from the test I plan to evaluate it, find any errors and if there are what improvements I can do to improve the device whether it be the efficiency or the look. Following this plan I hope to complete this project on time to a good standard. Below I have conducted a test to find the most suitable materials to make my can crusher from, I chose a simple technique using a grid and marking each material out of 10 and then finding the total, the material with the highest total is the most suitable material.
Can Crusher
Materials
PDS Performance Strength Materials Manufacture Maintenance Safety Design Transportation Cost
Rubber
TOTAL
3 4 2 2 7 9 2 9 7
Aluminum 8 6 7 8 8 7 7 9 8
45
68
Cast Iron 9 8 6 7 8 6 6 8 5
Steel 9 8 10 9 9 7 8 9 5
Glass 2 1 1 1 1 1 2 3 3
Copper 6 5 5 6 6 4 4 8 4
63
74
15
48
From my findings I have found that steel is the most suitable material to use to make the can crusher it is the most widely available type of metal and is the easiest to work with, the other items are either too fragile or expensive to buy or produce.
From my findings above I plan to use the same technique to find out what system I should implement for my can crusher such as should I make it electronically or manually? Can Crusher PDS Performance Strength Materials Manufacture Maintenance Safety Design Transportation Cost
TOTAL
Systems Electrical 7 6 7 6 7 7 6 6 5
57
Solar 5 3 9 2 9 7 6 3 2
Manual 9 8 3 8 3 8 6 9 8
46
62
As you can see a manual device is the winner here. I would of preferred to make it a solar powered can crusher but the college facilities are not capable of producing such items, so it had left me too choose out of a battery electrical system or a manual system, as stated above the manual device became more suitable. As well as it being more suitable anything electrical may add to the size of design which might make my design more of an eye sore which I did not want. Below I have conducted some spider diagrams of which I have scanned.
These spider diagrams will be useful to look back on and help refresh my memory for new ideas that I may come up with.
Findings There were a few ideas for my project one of them being a wildlife observer, the aim was to make a remote control camera mounted on a uav which anyone could fly or use. The unmanned aerial vehicle had to consist of the following things; • Lightness - Has to be able to fly easily, the lighter the product is, the longer the battery life • Quietness – The whole point is to observe wildlife so it needs to be quiet otherwise it could scare animals away. • Efficiency – This involves the battery life of the product and how long it can stay in flight before the life of the battery needs to be recharged. The way that it would be controlled is through a remote control similar controls to an r/c car, while the user was flying the device he or she would hover wherever they thought an animal would be, the camera would then transmit a live video feed to an on screen display in the middle of the controller a simple sketch is below;
If I had made this I would of needed allot of extra help with the design and making especially with the electronics, another factor would have been where do I get the materials from and what type do I buy, it wouldn’t be as simple as gathering steel and bending it into a circle and placing a fan in the middle of it, it has to be balanced which needs a gyro scope as well as streamline and flexible mould, with all of this in consideration there is one
Sina Fazel
material that could be suitable for the job, a light carbon compound preferably Carbon Fibre. If I was able to collect all of the required items then there would also be another two major factors which would affect the production and they are • College Facilities – I would probably need to mould a shape and the college has no molding machines • Time Frame – Such a project is a long dedicated one due to there being many factors to take into consideration Due to all of these factors I have chosen not to go ahead with this project and think of another design. After a few more days I had to think of another idea, I had been thinking about recycling and what I could do to improve how we recycle from the simplest things, that’s why I came up with the idea of making a can crusher it would be slightly more simple as it does not need any special materials which would cost allot of money. There are allot of can crushers on the market so I set out some guidelines I should follow to make it differ from other products. Requirements Of Product The design has to be made with careful consideration of the following things; • Ease of use • Fairly Cheap • Unique Action • Strong Material • Long Lasting i.e. Durable • Safety Ease of use – It must be fairly easy to use with the least amount of physical effort used so that it can also be used by people who are old and may have arthritis Fairly Cheap – The Product must be produced fairly quickly for mass production but at the same time cheaply, one way of doing this is making less assembly parts for the manufacturing
Sina Fazel
Unique Action – The way the can or the way the item crushes must differ from other products/competitors, as you want the customer to be drawn to your product Strong Material – The can crusher frame or its vital parts must be able to withstand the amount of force produced while the crushing is taking place whether it be in Sheer, Tension or compression, but the key is to keep the material at a minimum weight so the user can move the device from one place to another fairly easily Long Lasting – the product must be able to last a long life so that the customer gets “value for money” after all a long lasting and durable product is a sign of a well made design Safety – Safety requirements must meet British standards, it also must be safe to use, for example when crushing the can there is no risk of crushing your hand or the can flying out of its constraints during the crushing process, a way of overcoming this obstacle would be to add a closing lid in front of the can. Now that I have set some simple guidelines I made some simple sketches of designs;
Sina Fazel
From the four designs I chose to make the sketch with the star next to it. I chose this design because it seems to be the most efficient of them all, the other designs either wouldn’t work properly for example the bottom sketch the foot operated can crusher, it would just be too large to fit into a household kitchen, the one I have chosen is fairly small compact and seems to have a good concept that is likely to work below is a specification of my final idea and what I want it to achieve;
P.D.S – Product Design Specification Design Brief From market research, it has been decided that the can crusher needs to be designed for general household can crushing. The crusher will be portable and have a flat back so it can be put against a wall. It is important that it should look stylish so that it can stick out from other competitors. Performance 1.1 To be able to crush a 350ml aluminum can as well as steel tins 1.2 Lever should push all the way vertically down 1.3 It should be a manual device to use by hand 1.4 The product should be portable 1.5 Efficiency of the unit should be very high 2.0 Environment 2.1 The product should be silent/quiet 2.2 Cans may already be slightly crumpled 2.3 Should be a clean product as it is in a household kitchen 2.4 Temperature will be atmospheric temperature 2.5 For products which are at their “end of life” 2.6 Capable for recycling in a working environment 2.7 When in the making it should be relatively “green” to make and when disposed is recyclable 3.0 Product Life 3.1 The product will be on the market for 3 years followed by newer designs 3.2 It should last an adequate amount of time 3.3 There should be spares available 3.4 A repair service available if the product fails due to manufacture fault
Sina Fazel
4.0 Product Cost 4.1 The product should cost around ÂŁ10.99 Retail 4.2 The product should cost around ÂŁ5.00 to make in mass production 5.0 Material 5.1 Strong enough material to withstand a force produced while crushing a can 5.2 Strong but light 6.0 Aesthetics 6.1 Box Design 6.2 It should look and feel smooth 6.3 It should look shiny 6.4 The product should look sleek and sophisticated to compete with competitors 7.0 Product Dimension 7.1 Weight should not exceed 8kg 7.2 Height should not exceed 300mm 7.3 Width should not exceed 100mm 7.4 Depth needs to be enough for a can to fit in approx 100mm it can be adjusted to height needed 8.0 Ergonomics 8.1 Should be able to crush with little effort 8.2 Product should be suitable for all ages 8.3 The lever should not cause any strain injury on the wrists 8.4 The handle shall be shaped and made for good grip. 9.0 Safety 9.1 The product should be safe to use and not cause injury 9.2 A lid system should be made so that the can will not fly out 9.3 It should meet British standard regulations; BS EN 1515-2:2001 Joints BS 4500-5 Limits and Fits BS EN 10088- 1 Stainless Steel BS A 341:1999 Rivets BS 63222(2) Nuts BS 3019 Welding Sina Fazel
10.0 Legal 10.1 Possible act lies in the user injuring themselves by having access to moving parts during crushing operation After completing a product design specification I now need to calculate the production cost of my product so I have done some research into it as you will see below ;
Can Crusher Market Cost Part of our project is to use the internet and whatever resources available to find out the cost of materials and profit margins so below is the worked out cost of the whole can crusher using a variety of websites to buy parts from. I am intending to produce this can crusher at £5:00. Here are the calculations below EBay – Entrepreneur Called Metal Off cuts Description: Prime Quality 3.0 mm Steel Sheet Size: 500mm X 500mm = 250000mm² Cost: £10.58 www.technologysupplies.co.uk Description : Mild Steel 3.0mm Size: 500mm X 1000mm = 500000mm² Cost: £12.15 For obvious reasons If I had to buy the materials I would buy the sheet metal from technology supplies due to it being better value for money. For the hardware such as screws, bolts, nuts and washers I chose to use screwfix.com the list of prices are below;
Sina Fazel
www.screwfix.com Description : Masonry Philips Head (100 pack) Size: M6 x 10mm Cost: £15.80 = 15.8/100 = 0.15p Per unit Description: Bolts (100 pack) Size: M10 x 25mm Cost: £34.34 = 34.34/100 = 0.29p Per Unit Description: Nut (100 pack) Size: M10 Cost: £2.48 = 2.48/100 = 0.02P Per Unit
Description: Washer Size: M10 Cost: £1.63 = 1.63/100 = 0.01p per Unit After working out the cost of each unit I need to calculate cost of manufacturing each component I shall be making, to do this I have to calculate the surface area of each component once done I divide the surface area of the sheet metal to the surface area of each component, this will give me the number of components I can make on each sheet metal. This will then give me the cost of each part. Back plate Size: 275 x 145 = 40700mm² Per Sheet: 500000mm²/40700mm² = 12 back plates Cost Of Each: 12.15/12.2 = 0.9 = 90P Crushing Plate Size: 11230mm² Per Sheet: 500000mm²/11230mm² = 44 Crushing Plates Cost Of Each: 12.15/44 = 0.27 = 27P Link Size: 3600mm² Per Sheet: 500000mm²/3600mm² = 138 Links Cost Of Each: 12.15/138 = 0.08 = 8P
Sina Fazel
Handle Size: 15000mm² Per Sheet: 5000000²/15000mm² = 33 Handles Cost Of Each = 12.15/33.3 = 0.36 = 36p So now I have worked out the cost of each part I can now add all the expenditures I would need to make 1 can crusher; 4 Masonry Philips Head = 15p x 4 = 60p M10 Bolts = 34p x 6 = £2:04 M10 Nuts = 2p x 6 = 12p M10 Washers = 1p x 4 = 4p Back Plate = 90p x 1 = 90p Crushing Plate = 27p x 1 = 27p Link = 8p x 2 = 16p Handle = 36p x 1 = 36p TOTAL COST £4.49 After calculating all of the costs I have come to the conclusion that this figure is acceptable and I should buy these products and start production, although the price of the M10 Bolts seem to be fairly expensive compared to the other products. I shall find out in the future if its possible to find cheaper bolts as this could significantly cut my production cost. Profit Profit = profit, as a percentage of the cost = profit/cost 100 because I want to sell at an RRP of £10 I can now work out my profit 5.51/4.49 X 100 = 122 so that is 122% profit. Considering the total cost should include labor cost of 20% Per Unit as well as electricity cost of around 3% Per Unit plus rental of 10% Per Unit, Tax 10% Per Unit and Vat 17.5% per unit which is a net cost of £7.44, that’s a total net profit of approx 34% which is £2.56 I forgot to calculate waste material which is usually around 2% so that’s 10p per unit deduct 10p from the net profit and that’s £2.46. Net Profit = £2.46 Per Unit
Sina Fazel
Sina Fazel
Can Crusher Designs After thinking of what designs would be suitable to produce it came down to four possible designs, each vary significantly below is a picture of each design followed by its advantages and disadvantages following from that I shall justify the chosen design. Design 1
Design one is a foot operated design it is used by the user’s foot being pushed down on the foot plate, as pressure is being put on the foot plate the pivots allow the lever arms to extend outwards allowing the footplate to make contact with the can and crush it. Disadvantages • Likely to be unstable • The levers have no constraints for sideways motion • User could injure themselves relatively easily Advantage • It is a very quick technique • Looks different
Design 2
Design two works by the users turning the handle anti clockwise, because it has a threaded bar it slowly pushes the crushing plate down, when the user has finished crushing they then have to turn the
hand clockwise to bring it back up enabling the crushing plate to be locked back into place. Disadvantages • Extremely Slow • May require allot of effort • Thread may wear down Advantages • Not allot can go wrong • Can crush all the way down
Design 3
The following design would consist of 3 simple parts, one arm, one base and a hinge, it would work just like a hole punch lever arm, the user would push down with there hand and simply crush the can. Disadvantages • Flimsy • Ugly • Allot of force needed • Unstable Advantages • Cheap • Quick • Simple
Design 4
The following design can only be used by the users arm, it consists of a crushing plate, two links a handle which is constrained together by a handle, the user simply pulls the hand down and the links force the crushing plate to go downwards in a sliding guide. Disadvantages • Crushing plate cant reach the base Advantages • Easy to use • Can be wall mounted • Suitable for kitchen • Good leverage • Stable
After looking at all of the designs the conclusion is to go ahead and produce design four, this designs seems to be the most suitable for what I am intending to do (requirements of product) . The can when being crushed seems to be in a constraint position meaning that it can not fly out of its resting place which is safe as well as this it looks far different to current designs and this may appeal to customers. The other designs seemed to be very time consuming during the can crushing, It was intended to be quick as the user just wants to go into the kitchen after a drink and quickly crush the can to get back to there previous activity.
Modifications – Designs After making the can crusher there are a few things that I wish were designed differently, when implementing the design I did not take into consideration the stress and strains on the joints, meaning my current design is slowly buckling or after many more uses will crack in the corners and subsequently cause the can crusher to fail. The main 2 parts I would change are the crushing plate and handle, below I have written what I would do to change and improve the current design. Crushing Plate
The current design of the crushing plate has a major flaw, when the handle is pulled down on the can, the lever causes the crushing plate to push down on the can but what will happen is that the plate will be forced upward and subsequently bend upwards due to the joint being a 90 degree bend, I have drawn a red line on the joint where a crack could occur, as well as this I have drawn a red arrow explaining the direction of the bend. Taking this into consideration I have designed a simpler yet more effective design below, if had to make the can crusher again I would inevitably choose this design. As you can see the new design is a lot more Simpler, it’s a simple horizontal metal plate With a fillet groove in which will be where The Plate slides into the sliding guide, this new Design I think would work far better and more efficiently.
Handle
With the current handle design it has two flaws yet again concerning the joints of the part, the handle is to thin in the middle where the base meets the side and another where the main handle part meets the side. Because this is where most of the physical force is needed, it is not an efficient design neither safe as it could break as the can crusher is being used. So below I have sketched a design that would seem to be stronger and more efficient. With this new design the corners are now all filleted, so instead of the stress all being forced at one point it is now transferred around the corners making it less likely to snap. The red lines indicate where there would be major stress loads as well as implementing fillets there is also a pressed line which will add to the rigidity of the handle, helping it against twisting and buckling, I originally wanted to do this design but the college did not have the facilities to be able to produce this. Below is a real life example with cement and bricks as you can see in the corner all the stress is at one point causing the cement to crack. (http://en.wikipedia.org/wiki/Image:Stress.JPG)
Now for the actual can crusher pictures. Handle
As you can see the highlighted red area is the weak point that was mentioned previously before, you can see a drawn red marker line this was what I was going to file down to curve the edges to try and reduce the stress on the point.
As well as the bottom of the handle having weak points there are weak points at the top of the handle.
As the picture above shows the flaws in the handle another picture explains what was meant by pressed line on the handle the darkish raised box represents where it would be pressed if it was possible. This would help against any twisting and effectively making it more rigid.
Testing After producing the parts in the workshop it was time to assemble it all together, the two aims for the test are to see if the actual design works and if it can effectively crush aluminum cans below is a picture of the can crusher assembled.
As you can see the parts all assembled together nicely and the fittings were extremely flush, the picture on the right looks as if the back plate is bent but this is the illusion of the camera, I will now try to crush an aluminum can, As the can crushing will take place it will not be put under maximum force straight away but gradually increase the amount of forced used to visibly see if there are any faults, below is a picture of the can crusher in the stationary position and after can is crushed.
As you can see the can fits nice and tight in between the handles and crushing plate although it managed to crush the aluminum can there were a few problems during the test, the major one being that I had to apply allot of force around about 80% of maximum effort this was probably due to there not being enough leverage but this caused some of the parts to buckle and twist so below I will explain what happened and why it did. The main problem was the crushing plate, It had started to flex and it must of went past its elastic limit and started to neck, with continued use it would be highly likely that it will create a crack and fail. The picture explains the term necking.
Here is the picture of one of the views from the top;
The highlighted box shows where the stretching took place it started to rip along the bend you can tell because the crushing plate is not flush against the back plate.
This picture clearly shows the bend and how much it has ripped into the plate, originally this crushing plate was completely 90 degrees but as you can see from the picture it has bent the picture below shows the extent of the bend The gray line has been drawn to give a perspective on the amount of bend. There are two factors for the cause of this and they are the thickness of material and the alignment of the levers.
I found out that the drilled 10mm holes on the crushing plate were not symmetrically aligned, although I thought they were it was quite tricky drilling the holes on the crushing plate as the vice on the pillar drill would not hold the particular shape in place properly, this causes one of the arms to pull more than the other and causes the crushing plate to push against the sliding guide more on the one side ending up in a twisting motion. The picture below explains;
as well as this the sliding guide is not perfectly straight due to the sheet metal bending machine not gripping properly you can see the results below.
The screw is parallel and is there to give you a perspective of how much the sliding guide is not straight, all of this will result in the crushing plate to twist and buckle although the crusher did successfully crush the can it did not do it efficiently which is my main goal, by implementing the designs I wrote in the modifications section I hope to overcome these problems.
Evaluation The project evaluation seen below is for a can crusher aimed at everyone all ages its aim is to crush normal aluminum cans by the means of a lever and a crushing plate the whole idea of the project was to encourage recycling in your own home. The design consists of 6 parts which are bolted on to a back plate, the pack plate has two holes at the bottom where the handles are connected too, the holes act as pivot points for the handle to be pulled downwards, the handles then have a another hole where the link can connect to. The link acts as a connector from the handle to the crushing plate, as the handle is pulled downwards the link pulls the crushing plate with it, but because there is a sliding guide on the back plate the crushing plate is constrained within it and therefore is forced to go downwards a simple sketch is below explaining;
The only problem with this was that the measurements had to be extremely precise as I found out when making, the crushing plate was not a tight fit and it would rattle and want to bend upwards, as I stated in my project design specification I did not want this to happen as it would cause the can crusher to be noisy (2.1 Environment) but due to there not being enough time I could not fix this, as the crushing plate was the most fiddly part to make. If I had to make any changes it would be the design in the crushing plate and handle as all the other components seemed to be fairly strong. After testing I found out that the can crusher plate had a tendency to twist and bend due to the levers not being symmetrically aligned as well as the sliding guide not being perfectly straight.
The picture represents the sliding guide not being perfectly straight
When making the parts I encountered a few problems when making the back plate although it seemed a relatively simple part to make it was difficult and was tedious to bend especially because it is narrow, what happened was the already bent side would get caught under the vice not allowing to bend the other side accurately, in the end I had to ask for the teachers help.
I am fairly happy with the materials I chose as from my material research I did which you can see in the planning chapter, Steel seemed to be the best suitable for this project as steel has a higher yield strength 520 Mpa and ultimate strength of 860 MPa compared to aluminum or any other possible products, although carbon fibre is strong it is fairly expensive which would then make the production more expensive. The problem with the materials I chose was the thickness, they all varied from 3mm to 0.5mm if I had stuck to one thickness throughout the whole device there would be a more likely chance of the can crusher being more efficient (1.5 performance) and the stress would be distributed allot better across the whole device, I wanted to put some bends in the handles to make it more stronger but unfortunately the college did not have the facilities to do this, if I was able to do this it would make the handles allot stronger and help it to prevent bending as well as this it would enable me to keep the material allot thinner which would then save money in production. For the can crusher to work smoothly I had to round off all of the sharp edges so that the least amount of friction was caused, after a few uses it got worn in and worked very smoothly I intended to make the can crusher appealing by giving a coating of spray preferably a metallic silver colour but I only got as far as priming it as you can see from the pictures in previous chapters it has a grayish look to it, for now this will prevent the can crusher from rusting the reason why the preferred colour is a metallic silver was due to kitchens generally having a stainless steel look, so to the customers it would fit in with there other house hold utilities. The general production of the can crusher took approximately 5-6 weeks to make along with a few unfortunate incidents along the way such as the workshop area being vandalized and set on fire, it was a relatively time consuming process especially filing down individual parts, to file down about 20mm accurately would take around 15 minutes which was along time as we could only be in the workshop once a week for 3 hours. Another tedious factor was making the crushing plate the design was just too fiddly to be put into a manufacturing line, none of the parts really required any milling but with the new designs that have been drawn up in the modifications section they could now be milled allowing the time taken to make a part reduced significantly. As well as there being less time to make the parts this would also save on labor costs. Although the time saved would most likely be used up in a newer design which will introduce a safety feature that will have a sliding cover at the front of the device, this is to prevent risks to toddlers.
The size and shape of the can crusher is perfect, a can fits flush in between the crushing plate and handles, the length of handles are just right and it would fit nicely on a kitchen wall its light and extremely portable which as another major aim in my design specification, the general design of the can crusher works and it is able to crush an aluminum can but as stated in the testing section it required allot of effort around about 80% this is not acceptable due to the design being for all ages, if there are elderly users they could have difficulty in crushing the can this will go against the design specification. So some changes are required to prevent these flaws, the errors to fix in order are;
• • • •
Crushing Plate – Make New Design Handle – Make New Design Leverage – Preferably a little more leverage Manufacturing – Making more parts that can be milled will make production quicker.