RE: invesment casting from desktop printers

Date: Fri Mar 03 2000 - 17:00:48 EET


Yet I get personal emails from you at my NON-work related email address
asking me to stop!

I said in my note that the process, no wait a minute the MMII, was not for
us! We have gone around and around with Sanders and this equipment. We
purchased it two years ago and from the start we had trouble. Williams
International typically does not acquire service contracts rather we prefer
time and materials, in the case of Sanders Equipment that was the wrong
decision! Aside from that, the parts that we produce are small air foils, a
part that should be well suited for the MMII. The problems started with
poor reliability. We have only completed a few builds because the equipment
simply would not function long enough to complete. We would hear reason
after reason from Sanders yet when the problem(s) seemed fixed something
else would go! Rolf is quick to tell me that we knew the capabilities of
the equipment when we purchase it and this is true that's WHY we purchased
it. What Sanders failed to inform us was the fact that the equipment and
software were still in BETA and in my opinion still is! The latest version
of software STILL is not finished!

As an example of or problems...had JUST gotten the MMII back from Sanders
presumably with ALL of the new bells and whistles, upgrades and on and on, I
unpacked the equipment plugged it in and started a build. The machine
STOPED functioning within two days. As it turned out there was a service
tech. In the area so he spent 2 days with the equipment got it running and
the very next day it STOPED running and back to Sanders it went! That has
been our experience with Sanders and the MMII, over and over and over again.
I have TWO 2" binders that represent the repairs and fixes and replaced
parts that went into the MMII.

Instead of spending more money and development time making bigger machines,
time needs to be spent on making the ones you have function day after day
REGARDLESS of the size of the build or the length of time to complete the
build. You are the ones that made a piece of equipment with the build
envelope that you have, if your equipment can not function within that
envelope then change your spec sheet to something like: The MMII builds very
small accurate features ONE AT A TIME!


        -----Original Message-----
        From: Rolf Hubert []
        Sent: Thursday, March 02, 2000 11:30 PM
        To: Alex Salvi; Rapid Prototyping Mailing List (E-mail)
        Subject: RE: invesment casting from desktop printers

        Alex, I have no problems with criticism. The Sanders machine is not
        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
        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
        are. Our machine is not for everyone especially you. I have heard
        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
        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
        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
        the Sanders machine. Regarding the "Concept or Desktop" modelers,
        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
        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
        survive the gating or dipping processes. We have a Genisys in-house
        have yet to cast anything from this machine as the build quality is
        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
        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
        enough blades to make one completed ring(3 rings of blades per
        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
        engines! Despite the frustration with support removal and having to
        QuickCast patterns this is, in my humble opinion, the best route to
        prototype investment castings. We are now enjoying nearly a 100%
        rate with patterns generated on the SLA equipment.

        Beyond the specific RP equipment when generating a pattern for
        casting you have to consider several factors that may prevent the
        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
        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
        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.
                would be helpful in preparing for an upcoming presentation
                these technologies with 'industrial strength' RP systems
like SLA.
        If you
                have anything you would like to share it would be

                Kevin Dyer
                InterPRO Rapid Technologies

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