RE: [rp-ml] Sand core prototypes

From: Blasch, Larry <>
Date: Thu May 13 2004 - 15:03:26 EEST


If you are making 30-50 of the same sand core part, than just build the core
prints with any accurate RP process and make high temperature epoxy core
boxes to form the sand cores in.

I do aluminum sand casting pre-production patterns often with SLA for
quantities like that. I've also made tools for casting bronze, iron, steel
and stainless the same way. It also works well for "Green Sand" molding when
no cores are required.

Just build the patterns for sand casting -split at the parting line with
dowel pin holes already in the parts. Use the pin holes to match drill the
plate and this will guarantee that the pattern halves get mounted to the
mold plate accurately. Unless you plan on making more than 100 parts, you
can run SLA patterns in the sand without duplicating the plate. Glue the
pattern halves to the plate, and rig gates and runners as necessary. A final
coat of epoxy spray paint will help the sand pull clean.

I've run SLA "Master Patterns" with double shrink and used them to cast the
production tooling plate. That was in the distant past, now we just NC
machine the production plate if we need 100+ quantities.

The same goes for core prints. Depending on the core sand process you are
using, you may be able to just build the core box with RP and make the cores
directly. I never tried it with the newer "High Temperature" SLA resins, but
you may even be able to make shell cores in SLA core boxes.

I've found that most pattern makers won't have any problem working with
"accurate" RP masters. Typically, I just add a single shrink to the pattern
and no shrink to the core.


Larry Blasch
Design Engineer/CAE Systems Administrator
OPW Fueling Components
P.O. Box 405003
Cincinnati, OH 45240-5003 USA
Voice: (513) 870-3356
Fax: (513) 870-3275

-----Original Message-----
From: asrp []
Sent: Wednesday, May 12, 2004 12:59 AM
Subject: [rp-ml] Sand core prototypes

       We looking for some resource/advise for making sand cores for =
Aluminium castings. We have tried SLS sintered sand cores but process =
seems to be very expensive. We need at least 30-50 pieces. Has someone =
tried Zcorp machine to make the sand moulds? I'm keen for getting few =
ideas and technologies available, because it will be an ongoing process =
for us. Thanks in advance.

Rick =20
Received on Thu May 13 14:28:21 2004

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