I made it at the TechShop in Menlo Park! Here is a picture of the light diffuser in the vacuum forming machine as it is being formed. This machine uses a plug mold to vacuum form plastic parts like this. This machine does not work with a cavity mold because the vacuum does not seal until the mold platform is all the way up.
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Step 1: Mold Release
After it has cooled down, I push the RELEASE button on the vacuum forming machine to inject air to release the diffuser from the mold. In this example, the plastic is too thick and stiff so the part did not release using this method.
Step 2: Mold Modification to Release Diffuser Using Air Gun
Since the air pressure in the vacuum former is not strong enough to release the diffuser, I added a hole through the mold from the base to the top. High pressure air from the air gun can then be applied to through the hole to the top of the diffuser to pop it loose. I also added a piece of scotch tape over the hole to prevent the vacuum from sucking the plastic into the hole during forming. Works like a champ every time!
Step 3: Releasing the Diffuser Using an Air Gun
Here you see the diffuser popping off of the mold when air pressure from the air gun is applied to the top of the diffuser.
Step 4: Diffuser Is Vacuum Formed
Here you see the finished diffuser nicely separated from the mold.