The process is used in conjunction with thermoplastics. It offers rapid tooling for prototyping and for moderate production quantities, ranging from 250 to 3,000 parts per year.
Process
The vacuum forming process consists of heating a plastic sheet to forming temperature and then stretching it over a single-surface mould. A vacuum is applied to force the sheet against the mould, and the sheet is then ejected from the mould.
Once a vacuum forming has been created out of a sheet of plastic, a finishing operation will be needed in most cases to turn it into a usable product. Common vacuum forming finishing methods include pressing a blade through the product into a die underneath, roller cutting or press cutting, cutting with a CNC machine, or drilling.
Materials Options
Resins: Thermoplastics
Fibres: None
Cores: None
Advantages
- Vacuum forming offers a low cost, efficient, and rapid method of replication for prototyping and small series of certain shapes.
- Tooling can be produced very quickly.
- It is substantially cheaper compared to injection moulding.
Limitations
- Objects that are formed often stick to the mould, which is remedied by using a draft angle of three degrees or more in the mould.
Applications
Vacuum-formed components can be used in place of complex fabricated sheet metal, fiberglass, or plastic injection moulding. Examples include:
- Kiosks and ATM machines
- Engine covers in truck cabs
- Railcar interior trim and seat components
- Enclosures for medical imaging and diagnostic equipment such as MRI machines