How to Make a Vacuum Mold

This packaging was made through vacuum forming.

Vacuum forming is a moldmaking technique that is used to create objects used every day. Model airplane parts, model car bodies, product packaging, 3-D signs and even some boat hulls are just a few examples. A vacuum form machine is quite simple. It has a table surface with a vacuum underneath and a heating element above. They are separated by a track on which a clamp frame that holds plastic sheets can slide up and down.

Things You'll Need

• Vacuum form machine
• Thermoplastic sheet
• Object to be molded
• Scissors

Instructions

1. Set the object that you want to mold onto the vacuum base. It should have a flat base with no areas that the plastic could get caught on (called undercuts). For example, a plate turned upside down is a good candidate for vacuum forming. A plate turned rightside up is not, because the plastic would wrap under the edges and be difficult to remove.

2. Clamp a sheet of thermoplastic into the clamp frame so that it can freely raise and lower along the clamp frame's track. The thickness of the plastic will depend on how strong you want your mold to be. Thinner plastic is weaker, but it is also less expensive and easier to work with.

3. Raise the clamp frame to the heating element and turn on the heat.

4. Watch the plastic heat and begin to sag. Do not walk away at this stage: too much heat and the plastic will melt completely.

5. Lower the clamp frame and soft plastic onto the vacuum base. The plastic will begin to form over the object.

6. Turn on the vacuum to draw the air through the tiny holes on the vacuum base, sucking the plastic all the way down against the object.

7. Turn off the hear, wait 30 seconds, then turn off the vacuum.

8. Allow the plastic to cool for a few minutes.

9. Remove the plastic from the clamp frame and pop the object free.

10. Trim the excess plastic off of the mold.

References

• Do it Yourself Vacuum Forming For the Hobbyist
• Plastipedia: Vacuum Forming