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Aluminum molds for vacuumforming polycarbonate

Erik Vallbo

Apr 28, 2021
Hi everyone,

I'm making a luminaire in transparent polycarbonate for outdoor use and want to use vacuum forming/thermoforming. I want to do two forms for this project and I have been speaking to a few companies about making aluminum forms but they are very expensive. After some research I found an online service that can make the forms for half the price.

But I'm uncertain about what preferences I should have in order to get the the high quality I desire. I want to use polycarbonate for safety reasons like damage and so. The polycarbonate should be transparent and light will be projected through it, so the finish is very important. Since this is kind of a startup I won't make that many to begin with, I have and order for two now and if everything goes well the will order more, up to 20.

I have been talking to others about making a form in another material but polycarbonate needs a lot of heat in order become flexible. Therefor I think that I have to have an aluminum form.

There are a few options that I can consider when I order:
Aluminum quality: 2007/3.1645 - 5083/3.3547 - 6060/3.3206 - 6061/3.3211 - 6082/3.2315 - 7075/3.4365

Surface roughness: 3.2um Ra - 1.6um Ra - 0.8um Ra - 0.4um Ra

Finish: Standard, anodized, bead blasted or polished.

After some research I'm now looking at these options:
Aluminum: 7075/3.4365
Surface roughness: 0.4um Ra
Finish: Polished

Does anyone have experience in this and would like to give me some advices? All help is appreciated!

Thanks in advance


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May 31, 2011
upstate nj
I would look into using polyurethane tooling board. We use it at work with good results. After hundreds of pieces made on most of them they are in as new condition, and even after years of non use they are fine.