Vacuum Forming Homework Hotline

Vacuum forming is a method of molding sheets of plastic into 3D shapes using the force created by an air vacuum. Depending on quantities and complexity, vacuum forming can be an inexpensive and efficient technique.

When manufacturing plastic products, there are a handful of ways to go about achieving a desired shape. For relatively small quantities of products that do not require complex, multi-directional molds, vacuum forming is generally the method of choice.

Sheet-Stock Plastic

There are countless plastic types, thicknesses, colors, etc.  Your product application, design, budget, and user will all contribute to making a decision on which plastic to use. Once the material selection has been made, you will have sheets like this.


Molds can be made in a variety of ways depending, again, on the project, budget, quantity, and type of plastic being used. There are wooden molds, resin molds where liquid plastic is poured over a form to generate a solid plastic mold, and polished metal molds that minimize blemishes and can be cooled with water for higher production quantities. Typically, molds are a one-time expense and can be reused for all subsequent production.

Heating the Plastic

Heat is used to soften the plastic into a pliable state before it is put onto the mold.  The sheet stock is clamped into the vacuum former and is heated to a very specific temperature based on the chemical properties of the type of plastic. Once it is heated, the plastic begins to sag and is dropped onto the mold.


Once the plastic is placed over the mold, the vacuum pulls all of the air from between the plastic and the mold creating a pull action. This force ensures that plastic reaches every detail and crevice leaving a consistent molded form.


Once the plastic is molded, it has to cool completely before it is removed from the mold.  This minimizes the chance that the plastic will alter its shape.


After the plastic is cool, it can be removed from the mold and continue through the fabrication process of trimming, polishing, and assembly.

Vacuum Forming is one of the most common and cost effective ways to form plastic. unlike some other forming methods, vacuum forming requires a certain amount of craftsmanship in regards to temperature control, timing, and material selection.

Interested in learning more about vacuum forming and other manufacturing services we offer at Ehren-Haus? Check out our summary of capabilities page and give us a call to discuss your product.

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This entry was posted in Industry Tips and tagged manufacturing tips, Molding, plastic fabrication, plastic manufacturing, Product manufacturing Tips, ThermoForming, Vacuum Forming. Bookmark the permalink.

We create with thermoforming that offers economy and versatility

One of the most economical thermoforming technologies is vacuum forming. It offers great flexibility in the creation of custom molded plastics because production costs are relatively low.

How vacuum forming works

To vacuum form a plastic product:

  1. A sheet of thermoplastic material is heated in an oven.
  2. The heated sheet is set on a mold.
  3. A vacuum pulls air out of the mold, pulling the sheet against the mold to shape it.
  4. After the formed plastic cools and hardens, it’s removed from the mold and trimmed.

Advantages of vacuum forming

Industrial vacuum forming is a suitable replacement for other custom forming processes that use sheet metal, fiberglass or wood. That’s because vacuum forming can:

  • Produce very large items that may be lighter
  • Be more cost efficient for small production runs, or products requiring less detail and complexity
  • Speed items into production

When to use vacuum forming

Vacuum forming plastics is a good choice for:

  • Tight budgets
  • Time constraints
  • Lower volume, shorter runs
  • Items with large dimensions

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