1. VACUUM FORMING KEY STAGE 3 GCSE A LEVEL
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KEY STAGE 3
GCSE
A LEVEL
VACUUM FORMING

2. Advantages and Disadvantages
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Exam Questions
ELECTRONICS
The Process
June 05
Former
VACUUM FORMING
GRAPHICS
June 03
Advantages and Disadvantages
RESISTANT MATERIALS
June 04
Materials

3. HOME
Overview
In a nutshell, vacuum forming is where a thin thermoplastic sheet is heated until it is in its plastic state (i.e. flexible) and then it is stretched over a former and allowed to cool. When cool it becomes rigid again and so keeps the shape of the former.
Animation
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4. The Process HOME FORMER PLACED ON PLATEN
PRACTICAL NOTE: BEFORE PLACING THE FORMER ON THE PLATEN LIGHTLY DUST IT WITH TALCUM POWDER. THIS MAKES IT MUCH EASIER TO RELEASE THE FORMER FROM THE FORMING
PLASTIC CLAMPED SECURELY ONTO MACHINE
PLASTIC HEATED
TRIMMING
PLATEN RASIED
Once the forming is removed it needs to be cut out of the plastic sheet using a Gerbil Cutter
VACUUM APPLIED
LEFT TO COOL
PLATEN LOWERED
FORMING REMOVED
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5. Products HOME Bath (Acrylic) Blister Packaging (PET)
Chocolate Box Tray
(PVC)
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6. HOME
Former Design 1
To produce a successful vacuum forming the former needs to be carefully designed
the sides must have a 5-10° taper
SO that the forming can be easily separated from the former
any corners must be radiused (NOT ON BASE)
SO the plastic does not split when formed over them
any cavities must have vent holes
SO no air is trapped in the cavity preventing the correct shape being formed
the surface of the former must be smooth
SO that a high quality surface finish on forming
the former material must be stable when heated
SO it keeps its shape when hot
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7. HOME
Former Design 2
there must be no undercuts
OR the forming cannot be separated from the former
PRACTICAL NOTE: WHEN MAKING A FORMER KEEP THE WIDTH TO DEPTH RATIO 2:1 TO AVOID THINING OF THE PLASTIC SHEET WHILE FORMIMNG
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8. Former Materials (school)
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Former Materials (school)
In school MDF is usually the material used for making formers.
The benefits of using MDF are:
it has no grain
THEREFORE it is quick and easy to shape
it is dense
THEREFORE it is possible to get a very smooth surface finish
it is stable when heated
THEREFORE it will not distort under the heat of the vacuum former
it is quite tough
THEREFORE it can be used over and over again
Other Materials
Pine could also be used but as it has a grain it is more difficult to shape and also it may warp under the heat of the vacuum former. It is also more difficult than mdf to get a smooth surface finish on it.
Clay (wet) can also be used but only once as the former is destroyed removing it from the forming. Fired clay is too brittle to be used.
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9. Former Materials (industry)
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Former Materials (industry)
In industry an aluminium or epoxy resin former would be used because these materials are harder and tougher than mdf so the former can be reused many more times than an mdf one.
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10. Advantages BECAUSE the same former is used again and again
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Advantages
STATE/GIVE (B/C)
DESCRIBE/EXPLAIN (A*/A)
all objects produced are exactly the same
BECAUSE the same former is used again and again
it is a highly automated process
WHICH means lower cost
low tooling costs
WHICH means lower cost
high production technique
WHICH means that it will be able to meet the high demand for the product
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11. Disadvantages SO that it can be released from the former
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Disadvantages
STATE/GIVE (B/C)
DESCRIBE/EXPLAIN (A*/A)
forming must have sloped sides
SO that it can be released from the former
designs must be simple
BECAUSE complex shapes and fine detail are not possible
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12. SCT June 05 Q1(d) HOME QUESTION
The drawings below show the bulb reflector cone. It is made of a thermoplastic using the vacuum forming process.
outside view
sectional drawing
Explain two reasons why vacuum forming is a suitable process to manufacture the reflector cone.
(4 marks)
POSSIBLE ANSWERS
it is a simple shape (1)
MAKING the former simple (1)
the shape has sloped edges (1)
MAKING it easy to remove (1)
the high quality former (1)
MAKES the inside surface finish excellent (1)

13. GP June 03 Q1(d) HOME QUESTION CUT PLASTIC SHEET TO SIZE
Complete the block diagram opposite to show, in the correct sequence, five more main stages in vacuum forming trays.
PUT MOULD IN (1 mark)
CLAMP PLASTIC (1 mark)
Some stages have been done for you.
HEAT (1 mark)
(6 marks)
VACUUM FORM (SUCK DOWN OVER MOULD)
ANSWERS
COOL (1 mark)
Correct Sequence (1 mark)
REMOVE/TRIM (1 mark)
FINISHED TRAY

14. RMT June 04 Q4(b) HOME QUESTION
When vacuum forming, a mould or former is required. The manufacturer of the egg box uses a mould made form MDF
State two properties of MDF that make it suitable for making the mould to be used for vacuum forming.
For each property give a reason why it is suitable.
(4 marks)
POSSIBLE ANSWERS
it has no grain (1)
THEREFORE it is quick and easy to shape (1)
it is dense (1)
THEREFORE it is possible to get a very smooth surface finish (1)
it is stable when heated (1)
THEREFORE it will not distort under the heat of the vacuum former (1)
it is quite tough (1)
THEREFORE it can be used over and over again (1)

15. HIPS easy to mould BECAUSE of its low melting point
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HIPS
easy to mould
BECAUSE of its low melting point
electrical insulator
WHICH prevents short circuits
waterproof
WHICH keeps the contents away from the weather
tough
WHICH means the product can withstand knocks
lightweight
WHICH means that products will not be too heavy
available in a wide range of colours
WHICH means that products will appeal to wide market
rigid
WHICH means that contents are protected
scratches easily
WHICH means that products looks will deteriorate
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16. ACRYLIC BECAUSE of its low melting point easy to mould
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ACRYLIC
easy to mould
BECAUSE of its low melting point
electrical insulator
WHICH prevents short circuits
waterproof
WHICH keeps the contents away from the weather
available in a wide range of colours
WHICH means that products will appeal to wide market
durable
WHICH means that it will last a long time outside
available in clear and translucent
WHICH means that light can shine through products/contents visible
brittle
WHICH means that product will shatter if dropped
scratches easily
WHICH means that products looks will deteriorate

17. FURTHER INFORMATION GCSE Resistant Materials Text Book, Pgs
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FURTHER INFORMATION
GCSE Resistant Materials Text Book, Pgs
GCSE Graphic Products Text Book, Pgs
Focus on Plastics (Subjects/Technology/Focus Educational Software)
TEP Materials Selection (TEP Materials Selection)