Plastic Design 101: A Guide to Thermoforming and Injection Molding

September 21, 2021 7:17 pm Published by Leave your thoughts

Plastic is an amazing material with a nearly infinite number of useful applications. Manufacturers in just about every industry use plastic components in their operations, and consumers have come to expect to see plastic employed in all kinds of ways.

Here’s a basic plastic design guide for thermoforming and injection molding to help you understand some of the key concepts of plastic-component fabrication.


The thermoforming process involves melting plastic sheets into a predetermined shape. The plastic is heated to a very high temperature, enhancing its malleability and allowing it to be formed and shaped without risk of cracking or breaking. Once the plastic sheets are heated, they’re pulled down onto a mold, which is the inverse of the final, desired shape. The heated plastic takes the shape of the mold, then cools and hardens into the shape.

In simplest terms, it’s best to think of thermoforming as a stretching process, as what was once a flat sheet is turned into a larger shape with a larger surface area, while the sheet’s original thickness may be thinned down. Materials that are ideal for thermoforming include ABS, acrylic and polycarbonate plastics, and there are infinite possibilities for customization.

Some of the most common thermoformed plastic applications include:

  • Advertisement industry: Vacuum-formed exterior signs, point-of-sale displays
  • Aerospace industry: Seat backs, snack trays, cupholders, interior trim panels, covers, cowlings
  • Computer industry: Enclosures, keyboard covers
  • Industrial industry: Refrigerator enclosures, light covers, dispenser covers
  • Health and medical industry: Medical device components, prosthetic parts, MRI equipment enclosures

Injection molding

Plastic injection molding is ideal for creating products in both small and large runs. Injection molding can be tailored to any production need you may have, in any amount. If you already have a product or component in mind, talk to a reputable plastics company to help you through the design process. Injection molding is a precise process, so you’ll need a company who can fine-tune every part of your design as well as choose the right type of plastic that suits your applications.

During the injection molding process, a machine melts plastic with intense heat and injects the molten plastic into a mold. The mold essentially is a hollow, metal block that has cavities that reflect the desired, finished shape. As the plastic flows into the mold, the injection machine controls the injection speed and all cavities are filled with the plastic. After the mold is full and the plastic has cooled, the finished product can be removed from the mold.

Some of the most common injection-molded plastic components include:

  • Advertising industry: Point-of-sale displays
  • Building and construction industry: Hand tools, fasteners and accessories, window components, door components
  • Food and beverage industry: Food and beverage containers, processing equipment components
  • Medical industry: Surgical prep products, diagnostic test kits

No matter what you need to make in plastic, it’s helpful to work with experts in plastic design to ensure exceptional results. D&D Plastics helps you understand the nuances of plastic design, so you can craft the components you need with the right materials and the right processes.

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