We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is Thermoforming?

By Brenda Scott
Updated May 17, 2024
Our promise to you
About Mechanics is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At About Mechanics, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Thermoforming is a manufacturing process which involves heating a material until it is pliable, stretching it over a mold, and then cooling it so it retains the desired shape. A variety of materials, including bone and shells, have been processed in this manner for centuries, though thermoforming is now primarily used for shaping plastic sheets or films. Examples of thermoformed products include blister packing for pills and individual food servings, plastic trays, and even plastic pallets.

The most common method of thermoforming is straight vacuum forming. This process involves heating a sheet of plastic to its sag point and then lowering it into a recessed mold. The air is removed by vacuum, plastering the sheet against the walls of the mold. The plastic is cooled and then trimmed and removed if necessary. Equipment required for straight vacuum forming is generally much cheaper than the equipment required for pressure or mechanical processing.

A more expensive thermoforming method used for parts which require exact detailing is matched mold forming. In this process, a sheet of plastic is stretched between two matching, heated molds. The molds are pressed together and air bubbles removed by vacuum through holes in the molds.

When plastic sheets need to be molded into deep shapes requiring uniform thickness, pressure-bubble plug-assist vacuum forming is a preferred method. In this thermoforming process, controlled air pressure is exerted against the heated sheet to create a bubble. Once the bubble reaches the correct height, a male plug-assist is lowered, forcing the bubble into the mold.

Trapped sheet contact pressure thermoforming uses both vacuum and air pressure to force the heated plastic into a mold. This process requires a lower temperature, is faster, and has a finer finish. Vacuum snap-back processing is a slower and slightly more complicated process that can be used when uniform thickness is more critical. In this method, the heated plastic sheet is placed over a vacuum box which sucks it down into a concave shape. The vacuum box then releases the plastic, and it snaps back against a male plug mold.

Billow and matched die are two methods of thermoforming which do not use a vacuum. In billow forming, the heated plastic is attached to a billow, a chamber which blows air, and the air pressure presses the plastic against a mold. Matched die forming is used to create parts with two halves which mate. The heated plastic sheet is clamped together between two molds, and no vacuum or air pressure is required.

About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.