DesignHow does one avoid mistakes in the manufacturing process?

  • Start with sketches
  • Get your design engineer involved from the beginning
  • Get your design engineer involved from the beginning
  • Get your design engineer involved from the beginning

I wanted to make my point.

Vacuum thermo-forming is a process very unlike other methods of molding plastics.

It is not as much a science as it is an art form.  Many have considered it a “black art” in that the techniques have been kept secret and are not shared from shop to shop or person to person.

Because each shape may have difficult areas to form each technician that works on the project may go about forming or attempting to form the shapes a bit differently from the next person.  This is why consistency in the process from operator to operator within the plant is vital.

The shape you create may look really nice on paper or even in CAD (Computer Aided Design), however, it may not make a good candidate for the vacuum thermo-forming process.

It is always best to start with a shape that you KNOW can be molded before you spend a lot of time and money attempting to mold a monster.

Because of this we tend to stay away from allowing our customers to send us tooling they make.  There have been too many things come in that were monsters in the making and simply not formable.  The customer had wasted their time and were now going to cost us time and money fixing their creation.


Here you can see an example of a well designed part

Momma may be proud of what you carve up and offer to the vacuum forming shop but the guy that has to mold plastic around the tool may think otherwise.

This process of vacuum thermoforming enjoys the following in the design of the part:

  • Plenty of Radius

  • Generous Draft Angle (no straight walls)

  • Corners that are rounded as much as possible–avoid sharps

  • Space between shapes or other molds in the event this is a family tool

  • A ratio of 1:1 or greater.  1″ tall equals 1″ wide and so on.

  • No undercuts

  • No holes before the part is formed, just can’t do it.

  • Printing of photos is always best if not mandatory after the part is formed.

  • Consider attachment of other formed, injection molded, or machined parts to complete the product.

Following these guidelines will increase the successful formation of vacuum formed parts.

See you next time for a discussion of In-Line Thermoforming.

For more information, visit our website or call us today at 800-779-6925 for more information.