1. A mould must be created for the plastic to form around. It can be quite intricate but must have space for the plastic to be vacuumed into. In some cases, extra holes need to be added to the model.
2. The chosen plastic (depending on the use of the mould and size) needs to be heated until in a flexible state.
3.Air can be blown into the plastic to stretch it before vacuuming to create a tighter fit.
4. The mould is raised into the heated plastic and vacuumed to stretch around the mould.
5. The model is removed from the plastic to leave a vacuumed formed plastic part.
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Wooden block, wooden dowel used to create cross and border. |
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| First attempt, plastic did not mould into corners. |
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| Second attpemt, after drilling 3mm holes into the corners of each square, it was able to give a tighter fit, as air could get through the holes, giving deeper trays to be used when painting. Vacuum Forming in Schools Vacuum forming is a popular method of moulding plastic across schools as it is cheap, effective, simple and safe, while still teaching the properties and uses of plastics. Plastic is vacuum formed in many everyday items, so pupils will be able to relate to the process when they can see that what they own and buy has been processed in this way. What Plastics can be Vacuum Formed? Only thermoplastics can be vacuum formed, such as polyethene and PVC. For my Vacuum forming I used High impact polystyrene (HIPS) because its a cheap and tough plastic and easy to thermoform. Therefore it was suitable for a paint palet to be used by children as it would be durable. Benefits of Vacuum Forming in Industry Its a cost effective way to create many products including packaging. The same machine can be used for any packaging, with just the mould needing to be changed. |
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