RE: invesment casting from desktop printers

From: Pattison, Will (
Date: Fri Mar 03 2000 - 16:51:12 EET

i've been following this thread a bit, because no matter how many times
these conversations are repeated in the rp community- and it is frequently-
i'm still both amazed and amused that some people still don't get it. as a
former applications engineer at dtm, and a current customer of many rp
technologies, i can say with confidence that if you aren't getting the parts
you need out of your rp efforts, then either:

1. your application is wrong, or
2. your expectations are wrong, or
3. you are not running your equipment correctly, or
4. you are not maintaining your equipment correctly.

just as i've said about rapid tooling, all the rp technologies are good-
when used appropriately. whether it's a sanders, a sinterstation, a cnc
mill, or an sla-3500, it has to be recognized that they are nothing more
than tools. anybody that's ever turned a wrench knows that not every guy
who picks up a craftsman 14mm box-end is going to get the same results. if
you didn't know all the capabilities of the wrench when you picked it up,
and then you stripped a nut, you can't blame it on sears.

i also note that these conversations usually include vague terms like "thin"
and "rough". rolf's replies were a bit testy, but i can understand his
frustration. a large part of my work at dtm centered on investment casting,
and i can tell you that one guy's thin is another's microscopic, and karl's
"rough" might be somebody else's baby-butt smooth. not exactly what i would
call constructive critiscism.

will pattison, idsa
product development engineer

> ----------
> From: Tom Richards[]
> Sent: Friday, March 03, 2000 2:31 AM
> To: Alex Salvi
> Cc:
> Subject: RE: invesment casting from desktop printers
> Alex: We've found Sanders to be the only RP process which can produce
> small
> to tiny intricate parts accurately with good finish all-around. We've been
> running our machine for seven years. Yes, it's been upgraded over the
> years
> under service contract. It now runs quite reliably, albeit slowly.
> Tom Richards, Metallurgist
> At 09:50 AM 3/2/00 -0500, you wrote:
> >Sanders,
> >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
> >it.
> >Thanks for the info Karl.
> >
> >Alex
> >
> >
> >-----Original Message-----
> >From: Rolf Hubert []
> >Sent: Wednesday, March 01, 2000 9:22 PM
> >To:;;
> >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
> >finished.
> >
> >Regards,
> >Rolf Hubert
> >Industry Marketing Consultant
> >Sanders Prototype, Inc.
> >603-429-9700
> >
> >-----Original Message-----
> >From: []On Behalf Of
> >
> >Sent: Wednesday, March 01, 2000 2:55 PM
> >To:;
> >Subject: RE: invesment casting from desktop printers
> >
> >
> >Kevin.
> >
> >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
> > To:
> > Subject: invesment casting from desktop printers
> >
> > Hello
> > I would be interested in hearing from others who have used
> >ThermoJet, Z
> > Corp or Genisys systems to produce investment castings. This
> >information
> > would be helpful in preparing for an upcoming presentation that
> >contrasts
> > these technologies with 'industrial strength' RP systems like SLA.
> >If you
> > have anything you would like to share it would be appreciated.
> >Thanks!
> >
> > Kevin Dyer
> > InterPRO Rapid Technologies
> >
> >
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> >
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> >
> >
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> >
> >
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