Twin Sheet Thermoforming

For Strong, Lightweight, 3D Parts

Twin Sheet Thermoforming is a more technical version of the vacuum forming or pressure forming processes.  We begin by forming two sheets of plastic, essentially simultaneously, with separate molds on the top and bottom platens. Next, 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, thus causing the two sheets to weld together wherever the molds dictate a weld. Significantly, this twin sheet forming process creates beams, thus providing additional strength. The parts are hollow and have molded features on both sides.  Additionally, under certain circumstances, the Twin Sheet Forming process can be a better alternative than the Blow Molding or the Rotomolding processes.  See the comparison chart below!

Twin Sheet Thermoforming

In the twin sheet forming process needles are inserted into the cavity  created by the the molding process.  The needles are inserted between the 2 sheets to facilitate cooling, and to apply pressure.  Importantly, this piercing process will provide for 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. Check out our Twin Sheet Thermoforming Tips post.

Materials We Work With For Twin Sheet Thermoforming

With the Technical Twin Sheet Thermoforming process, we can work with all engineered thermoplastics including:
  • TPU
  • TPO – ThermoPlastic Olefins
  • FR – ABS Family of Plastics
  • PPE Family, including Radel & Ultem
In addition to the wide variety of materials we can work with in the Twin Sheet Process, we also have the ability to form parts 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 vacuum forming, thus enabling 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.  Read about what processes Twin Sheet Thermoforming can replace.

Twin-Sheet Thermoforming Advantages


  • 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

Learn More About Twin Sheet Thermoforming

Download our Twin Sheet Thermoforming White Paper and receive a sample part!