Plastic Thermoforming: Vacuum vs. Pressure vs. Twin Sheet

Plastic Thermoforming
Plastic Thermoforming

Vacuum forming, pressure forming, and twin sheet forming are plastic thermoforming services that create strong, lightweight parts without the porosity, sink/gate marks, and other undesirable surface conditions that are common to some other production methods. Compared to injection molding, these three plastic thermoforming processes also have lower tooling costs and shorter lead times.

If you’re considering thermoforming for your next plastics project, it’s worth comparing vacuum forming vs. pressure forming vs. twin sheet thermoforming. Gregstrom Corporation provides all three types of services and can help you to make the right choice. We also offer rotational molding along with value-added manufacturing. Contact us to get started.

Vacuum Forming

Vacuum forming is the simplest type of plastic thermoforming and is a good choice for quick startups and efficient prototyping. Temperature-controlled aluminum tools are not required, and wooden patterns and epoxy tools help control costs. As this video shows, vacuum forming heats a plastic sheet until it becomes pliable, stretches the material onto a mold, and then uses vacuum pressure to obtain the desired part geometry. Examples of vacuum formed parts include taxi tops and medical instrument cases and covers.

Pressure Forming

Pressure forming supports tight corners, texturing, and formed-in undercuts for recessed surfaces. This thermoforming process is a  good choice for low-to-medium volume runs and can support plastics prototyping. As this video shows, pressure forming applies positive pressure and vacuum pressure to the opposite sides of a plastic sheet. Examples of pressure formed parts include instrument housings and housing assemblies, medical laser assemblies, printer assemblies, and X-ray scanners.

Twin Sheet Forming

Twin sheet forming supports the production of strong, hollow products that can be made of dissimilar materials. This thermoforming process heats two plastic sheets simultaneously. Vacuum pressure draws each sheet to separate tools which then fuse together via high pressure. The result is a twin sheet part that’s attractive, structurally rigid, and detailed on both sides. For example, with the door on a medical device, a thicker sheet can be used on the outside for stability and a thinner sheet on the inside for rigidity.

Plastic Thermoforming from Gregstrom

Gregstrom provides the vacuum forming, pressure forming and twin sheet forming services that you need. Compared to many of regional competitors, we can also handle large, thicker sheets for heavy-gauge thermoforming. To discuss plastic thermoforming for your next project, contact us.