Vacuum Forming

Vacuum Forming is the Most Common Form of Heat Forming

Vacuum Forming is the most common form of thermoforming that we employ. In the plastic forming process, we heat the sheet of plastic to a malleable state.  At that point, we engage one atmosphere of pressure to press the plastic against the mold. Because we are using only one atmosphere of pressure, we can only mold parts that have large radii and not much detail.

Typically, pre-textured sheet is what we use in this process.  In addition, the part is usually made using a positive (male) mold with the controlled surface on the inside, against the mold. We can, however,  also use negative (female) molds with the vacuum forming process depending upon the part. Regardless of the mold configuration, once the part is molded it will need to be trimmed to remove the flashing (remainder of the sheet).  Also, at this point, we might perhaps perform some secondary machining to the part, such as holes.

Typical parts using the vacuum forming method are hot tubs, industrial pump covers – parts where design detail is not important.