TABLE OF CONTENTS Like compression moulding, thermoforming uses sheet rather than granules. In this process the sheets are clamped onto a frame and then heated to soften, but not melt, the plastic. A mould is then brought into contact with the sheet whilst a vacuum is applied. This draws the sheet onto the surface of the mould and forms the moulding. The moulding must be trimmed to remove the excess sheet material. This scrap can be returned to the sheet supplier to be used in the production of new sheet.
Polystyrene foam and polyethylene are commonly used in thermoforming. Both of these materials are used to produce packaging, such as fast-food boxes, pots and dishes. Drink dispenser cups are also commonly produced by thermoforming.
