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View Full Version : Is vacuum molding the best way to go??



screenzzzz
12-31-2006, 09:36 AM
Firstly I would like to wish everyone a happy and healthy New Year.

As opposed to my last thread on "how to vacuum form" where, I had an old machine and had to slowly learn the hard way, I would like to do this one by listening to idea's first.

The object of this set up is to create a die! The die will be used for embossing into hot 300f pvc. The only equipment I have at this point is a Solid state cooling systems Thermo cube 10-33-ID-I-LT, plus 2 6"x12" cold plates. My theory is based on extrusion of plastics. Where, the sheets are formed using chill rollers, i.e the molten plastic is compressed between two rollers set to a predefined thickness at a temperature lower than glass transition.

What has worked so far! I have embossed the hot PVC with a brass die, the die was kept cool by an a/c that I rigged, there was no sticking to that die, as long as it was cool.

Needs:

a. Perfect smooth replication of fine, convex line die.
b. A die that will not stick to hot Plastic, I will be using pvc, which I do not think is so relevant, I think the concept of any plastic product will have simular results.
c.Relatively hard durometer face surface.
d. The ability of the back surface to adhere to aluminium sheet (for support).
e. To be able to work in hot/cold temperatures with out shrinkage.

Products I have looked at include Teflon, silicone and overmolding silicone.

Teflon I found has a tendancy to creep as it travels through different temperatures, even Dyneon, which has less creep than most other Teflons
Also, the molding is to high temperature.

Silicone, usually has a soft durometer, I'm not sure how it will emboss. I have seen some that go as high as 85 A durometer that have a metal adative, and have not found one that is smooth.

My thought is vacuum molding, which is something I know nothing about! The things I have looked into regarding teflon/silicone are not written in granite, I am open to any opinions, as I found in my last thread, you blokes have great insight and I would really like to hear what you have to say

One of Many
12-31-2006, 04:02 PM
Embossing any flat sheet material I'd expect to displace primarily one side of the sheet. With any extruded or cast sheet, there will be no control of the shrinkage unless you could presumptively preshrink it and keep it flat, then emboss it?

The next possibility may be casting acrylics as DR mentioned in the previous thread. This would take a highly polished die and some form of parting compound.

Unfortunately I don't see either option as a fast cycle.

DC