Thermoforming is one of the oldest and most common methods of processing plastic materials. Thermoformed plastic products are all around us and play a major part in our daily lives. lt is a very versatile process used to manufacture a wide range of products from simple packaging trays to high impact aircraft cockpit covers. lt is also used extensively to make design prototypes of products to be produced by other processes.
The process, however, is basically the same in each case. in its simplest form thermoforming is the heating of a plastic sheet which is then draped over a mould whilst a vacuum is applied
The moulding is then allowed to cool before it is ejected from the mould using a reverse pressure facility. Thermoforming covers all processes which involve heat to shape polymers. Vacuum forming has generally been promoted as a ‘dark art’ and best left to companies with sophisticated processing equipment who are able to supply the facility and service. In this handout we hope to provide an insight into this adaptable process. However, it is only a guide and cannot impart the practical experience and skill that any user will eventually attain.
We hope it assists in taking the ‘guess work‘ out of the process and proves useful as a means of technical and engineering support. In the following sections we have provided a list of the various examples of applications for thermoformed parts along with an insight into the forming process and various associated techniques. A plastics section follows in which we examine materials and their characteristics.