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Vacuum Forming Questions and Answers

What is vacuum forming?
Vacuum forming is a process used to produce virtually any shape in plastic using heat, vacuum and air.
How does vacuum forming work?
Tooling that is the same as the inside face of the part required is fixed in the vacuum forming machine on a vertical moving table, then a sheet of plastic is clamped into position above the vacuum forming tool, two heaters one above the sheet and one below them sandwich the sheet heating it gently. When the sheet is at the required temperature the heaters are moved back the table is raised and vacuum is applied, once the plastic has been pulled down sufficiently the plastic is cooled using water spray and air, once cooled the tool is lowered, the plastic component is unclamped and now ready for finishing.
What shapes can be vacuum formed?
There are very few limitations when vacuum forming, as a guide it is best not have too many undercuts and where possible have a shallow taper on vertical faces.
Is vacuum forming cost effective?
Vacuum forming is regarded as the most cost effective way of producing plastic parts especially for low to medium production runs due to the relatively low cost of the tooling compared to other methods.
What thickness can I vacuum form?
Typically 1-6mm is sufficient depending on the application.
Does the material get thinner during vacuum forming?
Yes thinning does occur but this can be greatly reduced with subtle design changes and various vacuum forming techniques.
What kind of surface finish can I expect?
Generally you can achieve the finish required, certain aspects have to be taken into consideration these are thickness and finish of the material i.e. gloss, matt, smooth or textured. The design and construction of the tooling are equally as important. This is something our in-house design team can help you with.
Do I need a professional drawing of my product?
No a professional drawing is not required as we can make your product from a sketch or a sample.
Can deep parts be formed?
Deep parts can be formed providing the vertical face has a taper, to ensure the material does not thin too much a plug may be used to help push the material onto the tool.
Is tooling expensive?
Vacuum forming tooling is considered to be inexpensive compared to most other forms of plastic part manufacturing. Tooling can be made from wood for 1st off and prototype parts.
What quantities can be produced?
Wooden tooling is used for the prototyping, resin tooling will produce thousands in small batches, aluminium tooling will produce thousands at a time and out last the life of the product.
What plastic materials can be formed?
There are a large number of plastics that can be vacuum formed the most commonly used are ABS,HIPS,HDPE,PVC,ACRYLIC,kydex and POLYCARBONATE.
What is the maximum size for vacuum forming?
The maximum size for our machines is 2000mm x 1000mm and within this size single formings or multiple configurations can be achieved.
What tolerances can be achieved?
With the use of skilled pattern makers and cnc machines for the more complex tooling, tolerances between 0.10 and 0.25mm can be expected.

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