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andrew888
05-08-2007, 05:34 PM
Hello all:

Does anyone know how to cast Aluminum powder filled composite Polyurethane? The people at Super-tech cast CNC parts out of this stuff in-house. They say it is comparable to aluminum. If this is true and low cost it would make CNC router building ideal. Here's a quote from the Super-tech guys:

"Super Tech & Associates fabricated a set of molds that produced eleven different parts. The components are made from a composite Polyurethane and Aluminum powder. The components produced have approximately the same strengths as if they were produced from machined aluminum. The completed machine is suited for working on non-metallic materials when used as a computerized router. When used as a Plasma Torch the composite components have the added advantage of being non-conductive and isolating the motion control stepper motors from the electrical noise produced by the Plasma Torch."

If anyone knows of the formula for casting the polyurethane and components
It would be greatly appreciated.

Preston E
05-10-2007, 08:25 AM
Hi Andrew,

I went and had a look at thier site to see what they were saying. My background is polymer chemistry, particularly polyurethane and polyurea...thus my interest.

They say approximately the same strengths as aluminum...well that depends on what strength properties they are speaking about...tensile, I highly doubt...impact maybe... compression, good but not as good as the real thing...

They are just filling a two part polyurethane with aluminum powder, plain and realitively simple. It's likely a TDI/PTMEG based system and then the aluminum powder has been dried in an oven to remove all traces of moisture so as not to creat CO2 gas when reacting with the isocyanate before cure has taken place...this would cause foaming to occur

Molding is much cheaper than machining aluminum or casting aluminum, but they also say this is for machining non-metalic parts...and likely as a slower feed than one could with aluminum brackets...

Hope that helps a little.

Regards,

Preston

andrew888
05-10-2007, 03:35 PM
Hello Preston:

Thanks for the information. After you wrote to my post I went on www.smooth-on.com and found a
product called c-1508 and it has some of the characteristics you mentioned. See the attached PDF.
What do you think? Any help will be appreciated.

Andrew

Preston E
05-11-2007, 04:30 PM
Hi Andrew, I had a look at thier data sheet...it's quite good for an MDI polyurethane...but now where near the properties of an aluminum like 6061-T6

For example the urethane is 6200 psi tensile the aluminum is 42,000 psi tensile.

The Modulas of Elasticity of the Aluminum is 10,000,000 psi....the urethane is a meer 43,000 psi...

Not saying that it will not work for some applications, just we are not talking apples and apples...more like a pea and a 40 pound watermellon...

Hope this has helped.

Best Regards,

Preston



Hello Preston:

Thanks for the information. After you wrote to my post I went on www.smooth-on.com and found a
product called c-1508 and it has some of the characteristics you mentioned. See the attached PDF.
What do you think? Any help will be appreciated.

Andrew