What is the plastic thermoforming process?

Plastic thermoforming is a multi-step process. Here is a breakdown of this process:

1. Plastic material is selected. Thermoforming is a process that involves heating thermoplastic sheets so that they harden into a particular shape. Popular plastic materials used to create these sheets include ABS, PVC, PET, PETG, polycarbonate, and high-impact polystyrene. The thickness of the plastic sheet depends on the intended application: thin for packaging, thicker for structural parts.
2. The thermoplastic is heated. After being clamped into a frame, the flat plastic sheet is heated to the necessary forming temperature in an oven. At the proper temperature, the thermoplastic becomes soft and pliable but doesn’t melt.
3. The thermoplastic is molded. Once the plastic sheet has been heated to forming temperature, it is moved to a mold that defines its final shape. There are three main methods of plastic thermoforming:
   1. Pressure forming: Vacuum pulls the sheet onto the mold, then additional compressed air pushes it down.
   2. Vacuum forming: The sheet is placed over a mold, then air is removed, creating a vacuum that pushes the plastic tightly against the mold.
   3. Mechanical forming: A mechanical plug pushes the sheet into the mold before vacuum is applied.
4. The thermoformed plastic is cooled. This process happens while the plastic is still on the mold. As it cools, the plastic hardens and retains the mold’s shape. Cooling can be natural, or assisted with fans or water.
5. The plastic component is finished. The formed part will be trimmed from the surrounding sheet metal using either CNC routers, die cutting or laser trimming. Afterward, any additional finishing steps will be completed to conclude the plastic thermoforming process.