Forming: Vacuum vs. Pressure

There are two common types of thermoforming: pressure and vacuum. Kenson provides both of these manufacturing services in-house. The brief descriptions and detailed illustrations below help distinguish these two processes.

Vacuum Forming - During the vacuum forming process, plastic is heated in a high-temperature oven to make it pliable. A vacuum is formed between the mold cavity and the thermoplastic sheet. The vacuum pressure (which is approximately 14 psi) forces the sheet to conform to the mold and form the desired shape of the part.



Pressure Forming - During the pressure forming process, plastic is heated in a high-temperature oven to make it pliable. A vacuum is used under the sheet while air pressure (anywhere between 50 psi to 100 psi) is applied on the backside of the sheet. This additional pressure from the air helps force the sheet into the mold, making it easy to form thicker materials and create more intricate details such as undercuts, grilling and sharp corners.