I don't actually cast them but I design the patterns on
Rhino, have them made on a stereo lithography machine and them
have them cast by a local foundry. I then do the machining on
my CC mill. I have bought an old heavy duty NC mill and I am
in the process of replacing the old controller with PC
technology to do the patterns and the machining.

Paul Lamar

Paul,

I find this very fascinating.  There is no place around here
that teaches this kind of thing any more because of liability
reasons.  Too many hippies were getting ground up in the
machinery.  Nevertheless, I bought a little tiny mill from
Harbor Freight the other day.  I am trying to teach myself how
to use it.  I have books, but they don't substitute for the real
thing.

You must have some kind of machine shop company or something to
have all that great equipment.  If you can do stereo
lithography, then you should also be able to do investment
casting from the stereo lithography prototypes.  Also, I have
heard of wax printers.  They are basically ink jet printers that
print with hot wax thousands of layers to get a 3D object.  Then
the wax core is used for investment casting.

>From the looks of your parts, they look like they are sand cast.
What kind of process do you used to make the sand molders with?
Also, what kind of alloy do you have poured?

Dennis.

I borrowed the stereo lithography machine at the local junior college
by taking a course there.

The sand molds themselves are made at the foundry. They use some green sand molds
and some dry sand molds. The dry sand molds are used in cores made in core
boxes that I supply. It is an art and I suggest getting a book on the
subject as it is real complicated to explain. I used to have several
businesses and my CC mill is left over. It is now about 25 years old.
The NC mill I just bought and they can be had for as little as $3000.
Usually with bad controllers.

Paul Lamar
 
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