Twin-Sheet Thermoforming


twin sheet thermoformingTwin Sheet Thermoforming is a process of vacuum forming or pressure forming two sheets of plastic, essentially simultaneously, with a separate mold on the top and bottom platens. Once the plastic has been molded, it remains in the molds, and while still at its’ forming temperature, the two molds are brought together under high pressures, causing the two sheets to weld together wherever the molds dictate a weld. This process creates beams to provide strength. The parts are hollow and have molded features on both sides.

Needles are inserted into the cavity in the molding process, between the 2 sheets to facilitate cooling, and to apply pressure. This will also allow pressure equalization as the part changes elevation.

We refer to our Twin Sheet Thermoforming capability as “Technical Twin Sheet”® thermoforming. ATI has refined the process of “Technical Twin Sheet”® forming, which emphasizes our ability to work with tight tolerances and the full spectrum of engineered polymers.

Materials We Work With

With the Technical Twin Sheet process, we can work with all engineered thermoplastics including:

thermoforming plastics

  • TPU
  • TPO – ThermoPlastic Olefins
  • FR – ABS Family of Plastics
  • PPE Family, including Radel & Ultem

We have had success using:

  • Materials With Different Thickness for Either Sheet
  • Different Materials for Either Sheet
  • Contrasting Colors for Either Sheet

With our process of Technical TwinSheet Thermoforming®, we have stretched the limits of regular Twin Sheet forming, allowing us to meet significantly higher tolerances in trim and molding. Moreover, we have developed the tooling and knowledge to hide the parting line, allowing us to produce very cosmetic parts.

The Twin Sheet Process possesses the following advantages over blow-molding and rotomolding


• Tooling and Machines Are More Cost-Competitive For Small to Modest Run Sizes
• Each Sheet May Be A Different Thickness, Material or Color
• More Flexibility With Parting Line Structure Is Possible
• Ability To Produce Very Cosmetic Parts
• Many More Resin Types Are Available In Twin Sheeting
• More Structural Beams Can Be Created In Twin Sheeting
• Much Higher Production Rates

For more information, download our Twin Sheet Thermoforming White Paper and receive a sample part!

Proceed to Twin Sheet Thermoforming White Paper