RE: invesment casting from desktop printers

From: Rolf Hubert (
Date: Fri Mar 03 2000 - 06:29:36 EET

Alex, I have no problems with criticism. The Sanders machine is not for
everyone as I stated. When a potential customer asks me if my system can
produce concept models, I pass them on to all of my competitors. Karl knew
the performance of the system before it was ever purchased.

-----Original Message-----
From: []On Behalf Of
Alex Salvi
Sent: Thursday, March 02, 2000 9:51 AM
To: Rapid Prototyping Mailing List (E-mail)
Subject: RE: invesment casting from desktop printers

This is an interesting customer relations approach...
I'm beginning to see the light... now I understand why Al Hastbacka
responded the way he did back in mid January.
Does Sanders not like criticism or competitors?
I guess if you can make a machine that can build .0005" layers (as I read in
Rapid Prototyping Report Vol10, N2, Feb 2000 page 6) then you can afford to
loose a few customers because your machine is so great that everyone wants
Thanks for the info Karl.


-----Original Message-----
From: Rolf Hubert []
Sent: Wednesday, March 01, 2000 9:22 PM
Subject: RE: invesment casting from desktop printers

Karl, you bought these 2 machines knowing how precise but slow these systems
are. Our machine is not for everyone especially you. I have heard nothing
from you that makes any sense. Why don't you do yourself a favor and sell
it to someone who would appreciate them. We have delivered over 400 machines
and very few customers have problems like you.

Our machines are for dimensionally accurate, smooth, small parts. We build
turbine blades that you couldn't even begin to do with other systems. Why
don't you try stopping the verbal abuse. You bought systems that frankly
you shouldn't have, shame on you.

I can't even imagine why you built a model that took 650 hours, at least it

Rolf Hubert
Industry Marketing Consultant
Sanders Prototype, Inc.

-----Original Message-----
From: []On Behalf Of
Sent: Wednesday, March 01, 2000 2:55 PM
Subject: RE: invesment casting from desktop printers


We have investment cast from all of the machines that you listed including
the Sanders machine. Regarding the "Concept or Desktop" modelers, These
machines are ok for products that do not require very tight tolerances. In
general we have found that the parts on these machines are typically blocky
with little or no detail and have no thin wall features. This is not to say
that the equipment can not build these features but that they may not
survive the gating or dipping processes. We have a Genisys in-house and
have yet to cast anything from this machine as the build quality is less
then desirable for one of our cast parts. The equipment sits idle for 90%
of the year and the other 10% it is running crude small scale mockups. We
have cast parts run on the Z-Corp and Actua(ThermoJet) equipment and for
blocky parts they are ok although the surface finish on the Z-Corp was a bit
rough at best! We have 2 Sanders machines in-house (an MM6 Pro and MMII) and
although the bladed products we build on these machines are small (about the
size of your thumb nail) it took about 630 hours of machine time to complete
enough blades to make one completed ring(3 rings of blades per engine)!
These machines are headed for soon!

We also have 2 SLA-500s and with these machines have had the most success in
the casting arena! As an example on one build I had 500 parts run in less
then 2 hours and in a week they had been cast, cleaned and installed in
engines! Despite the frustration with support removal and having to seal
QuickCast patterns this is, in my humble opinion, the best route to
prototype investment castings. We are now enjoying nearly a 100% success
rate with patterns generated on the SLA equipment.

Beyond the specific RP equipment when generating a pattern for investment
casting you have to consider several factors that may prevent the part(s)
form completing. All of which should be considered even when using
conventional wax patterns. The longer I am involved in this industry the
more I realize just how much of a black art this process is! There are no
standards regarding gating, burnout, shell materials, and thickness,
preheat, melting temperature and pouring temperature! We have tried
solidification models and flow analysis and have found that our best first
guess is as accurate as the results from the analysis.

I'm sure this is much more then you needed but one can not give a simple
answer with out a minimal amount of background. I hope this helps!

Karl Denton
Lead Engineer
Williams International

        -----Original Message-----
        From: Kevin Dyer []
        Sent: Wednesday, March 01, 2000 12:31 PM
        Subject: invesment casting from desktop printers

        I would be interested in hearing from others who have used
ThermoJet, Z
        Corp or Genisys systems to produce investment castings. This
        would be helpful in preparing for an upcoming presentation that
        these technologies with 'industrial strength' RP systems like SLA.
If you
        have anything you would like to share it would be appreciated.

        Kevin Dyer
        InterPRO Rapid Technologies

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