Pressure forming is a process used to form plastics into predetermined shapes. With pressure forming, a hot plastic sheet is forced against a mold. Usually, this mold is a female mold, which means it is concave. Compressed air is then added to the back of the heated sheet in order to form the plastic with the mold.
The air pressures used in pressure forming increase the amount of detail that can be picked up by the plastic from the mold. Therefore, pressure forming is more effective than vacuum forming for projects requiring more attention to detail. This is possible because pressure forming is capable of creating up to five times as much pressure as vacuum forming. Products made with pressure forming also do not run the risk of excessive thinning, cold flow, or other problems associated with vacuum forming.
The high amount of air pressure used with pressure forming also makes it possible to achieve sharp edges and undercuts when necessary. It also has a low tooling cost and short lead time, while still allowing the creation of textured surfaces and products in a wide range of colors. The end result of pressure forming is an object with the same level of quality as one that has been created through injection molding or structural foam molding.
Pressure molding is a sensible alternative to injection molding when small quantities of products need to be created. It takes less work and costs less money to set up molds for pressure forming than for injection molding. Also, pressure forming is capable of creating the same detail and quality as injection molding. For large runs, however, pressure forming is not always the best choice, because the molds are not as long lasting as those used with injection molding.
Pressure forming is used to create a wide variety of plastic products. Typical products made with pressure forming include shrouds, covers, equipment housings, bezels, bases, internal parts, and component parts for use in business machines, computers and peripherals, telecommunications, bio-medical applications, electronics, and instruments.