Vacuum Forming

Vacuum Forming

1. Vacuum Forming is a manufacturing process that can shape a variety of different thermoplastic sheet. A vacuum is used to suck the air from around the mould, forcing the plastic to take the shape of the mould/former.

2. Vacuum forming typically produces products such as baths, yogurt pots and sandwich packaging. The typical plastics used are ABS, HIPS (high impact polystyrene), Polythene and Acrylic.

3. Advantages

   • The process makes smooth, open shapes
   • Once it is set up, it is a rapid manufacturing process
   • The machinery is reasonably priced

4. Disadvanatges

   • There is further finish required after the process
   • Only hollow products can be produced
   • It is very difficult to produce shapes with sharp corners

5. Process

   • 1. The mould is lowered into the vacuum forming unit
   • 2. The plastic sheet is clamped in place over the top
   • Heat is applied until the plastic is soft, then the heating unit is moved away
   • The mould is raised and pushes the plastic into shape
   • The vacuum is turned on, suctioning the plastic onto the mould
   • Air pressure is applied to release the plastic