Thermoforming is a manufacturing process where a single sheet of material is formed around a single sided mold. This type of manufacturing uses thermoplastic sheets heated to a malleable state. There are three different types of thermoforming methods. Vacuum forming, where the air is pumped out of the mold forcing the sheet of plastic onto the mold walls.
Pressure thermoforming primarily uses an air vacuum to pull the plastic sheet to the mold walls. However, air pressure is also used on the opposite side of the plastic sheeting. This ensures the plastic is forced into all corners and ensures that all the design elements are crisp.
Mechanical thermoforming does not use air vacuuming or air pressure. A mold plug forces the plastic sheet down into the mold. The plug is the opposite shape of the mold being created. When the two pieces come together it creates a snug fit of the plastic sheeting between the layers.