Posted by Rob Helmke | Thursday, July 17, 2014 0 Comments


As thermoforming specialists, the PI team consistently gets questions from people asking what exactly the thermoforming process is and how to use it to create a custom packaging design. Here, we’ve outlined some of the basics behind the thermoforming process, as well as the different forming methods you can use for your products’ packaging: vacuum, plug assist and plug assist pressure. Consult with our guide to see which could work best for your plastic packaging design.

Custom thermoformed plastic packaging designs

What Is Thermoforming?

Thermoforming is the process used to create custom plastic designs. To develop a thermoformed design, the packaging team stretches a heated sheet of plastic over a mold to create a one-of-a-kind design. To create these packaging designs, packaging specialists contain air pressure in a designated box. After the packaging design cools into the shape of the mold, the packaging team will trim and assemble the design. Thermoforming is used when the pressure on a plastic sheet exceeds 15 lbs. per square inch, up to 150 lbs. per square inch. Packaging created for the food, pharmaceutical and electronics industries all utilize thermoforming.

Vacuum Forming

Vacuum forming, used for creating packaging designs with that do not require depth or thickness, utilized a "simple" version of the thermoforming where a sheet of plastic stretches over or into a female mold. With the use of negative air pressure, the plasticpackaging design forms over the mold. Companies tend to prefer vacuum forming because it is more cost effective and has a streamlined process. The vacuum forming machines cost less to operate, and the materials tend to be less expensive as well. Because these designs are not as intricate, vacuum formed packaging also requires less time to create. However, vacuum forming does not yield as many products as other packaging design methods, making it more ideal for shorter runs.

Plug Assist Forming

Plug assist packaging formation utilizes a male plug tool that mounts over the machine to force the plastic material into the female cavity and create the plastic packaging design. The plug may be constructed of urethane, aluminum or syntactic foam. Because this method has a consistent fill, it can ensure a similar thickness for each run. Plug assist forming can also prevent any webbing in the packaging design.

Plug Assist Pressure Forming

Plug assist pressure forming is very similar to plug assist forming, yet the two have key differences. A plug still mounts over the material as in plug assist forming, but this time, air vented under the sheet applies pressure onto the plug side. The temperatures in plug assist pressure forming must remain consistent to ensure desired results. Have any additional questions about thermoforming or which method could work best for your packaging designs? Contact PI today.

The Secrets of Successful Packaging


Topics: Custom Packaging, Thermoforming