RE: [CAD_CAM_EDM_DRO] Inverse of G-code

Hi Bill -

We were pressing .063" 6061-T0 aluminum, about 120 in^2 area, over
a male aluminum pattern about 2" deep. I don't know how much
pressure that required, but the press used an 8" cylinder powered
by a typical hydraulic pump unit. The urethane we used was a
fairly stiff grade that can be purchased in thick sheets through
McMaster-Carr (#8716K69, for example). The urethane slab has to
be a couple times thicker than the depth of the mold/pattern. It
was amazing how much the slab distorted and squeezed out the
edges, only to return to its original shape. You'll probably want
to use a low-strength grade of metal.

Regards,

Carlos Guillermo
VERVE Engineering & Design

-----Original Message-----
From: W. P. McGown [mailto:bmcgown@...]
Sent: Thursday, September 18, 2003 2:55 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] Inverse of G-code

> Bill -
>
> If you have access to a high tonnage press, you might just use a
> slab of urethane as the "positive" die. I've worked on parts

that

> were formed this way in aluminum. The urethane acts like a

fluid

> to push the metal into the mold, and then returns to it's

original

> shape when done.
>

Wow, Carlos, what an idea!! Even if it does not work it sounds
like a
really fun thing to try! I have a press that uses a 20ton jack as
power
unit. Do you think that would be powerful enough?

Also, could you suggest a source for the urethane?

This sounds like fun and since the material will either be very
thin
stainless, aluminum or copper this might be the way to go!!

Thanks a lot.

Bill
On a bayou in Mississippi where we are just beginning to get a
taste of fall