The process of vacuum forming is used to make a wide variety of products such as car dashboards, speaker casings, and even product packaging. A simplified form of thermoforming, in vacuum forming, a sheet of plastic is heated to the forming temperature, stretched on to a mould with a single surface and then forced against that mould with a vacuum.
Though vacuum forming is usually used to forming shallow depth plastic parts, it is not restricted only to plastic. If the formable sheet is pneumatically or mechanically stretched before it is brought into contact with the mould surface, it is also possible for relatively deeper parts to be formed.
Conventionally, thermoplastics are the most suitable materials used in vacuum forming, the most common of which is high impact polystyrene sheeting (HIPS), which also happens to be quite easy to use. The thermoplastics are moulded to form the desired shape. Transparent materials such as acrylic, which are widely used in applications for military compartments for rotary wing aircrafts or fixed wing aircrafts and in aerospace, like as passenger cabin window canopies can also be produced by vacuum forming.