Gary, thanks for your reply.
We know of foundries producing wall thickness' as small as .030 in. but
those walls were small in height and opened up into a larger cavity
allowing for movement of the resin when firing the slurry. We have
produced wall thickness' of .100 in. and they seemed to drain ok. We
are experimenting with beam comp and overcure parameters trying to open
up the meddle of the cavity while staying within tolerances. One thing
we found out while talking to the 3D people is that with the intensified
curing process during the lasering of the quickcast build style, the
resin trapped inside the wall thickens to as much as ten fold. This
hinders the draining process considerably on thin walled geometry's.
Have any of foundries you spoke of produced long thin walled parts? If
so, can you tell me the name of the company and a contact person to
speak to?
-----Original Message-----
From: Gary Vassighi [SMTP:Gary@3D-CAM.com]
Sent: Tuesday, December 01, 1998 2:34 PM
To: 'Paul Hanna'; rp-ml@bart.lpt.fi
Subject: RE: QuickCast
Paul, The thinest wall we can drain is .065" to .070" made on
an
SLA500 with a gas Laser. My understandin is that solid state
Lasers
on SAL5000 have a slightly wider beam and build thicker walls
which in
turn increases the minimum wall thickness for proper drainage.
To
find the minimum wall you may drain, build a part with varying
wall
thickness from .150" to .040". You will be able to measure the
limits
after drainage. Some foundries cast parts with walls as thin
as
.030" without much problem.
Gary Vassighi
3D-CAM, Inc.
9139 Lurline Ave.
Chatsworth, CA 91311
Phone: 818-773-8777
FAX: 818-773-0979
http://www.3d-cam.com
> -----Original Message-----
> From: Paul Hanna [SMTP:phanna@CESSNA.TEXTRON.COM]
> Sent: Tuesday, December 01, 1998 10:16 AM
> To: rp-ml
> Subject: QuickCast
>
> I am currently trying to produce a QuickCast pattern that has
proven
> to be a challenge. As a result, I have a few questions I
wanted to
> pose to the list. First a quick overview.
>
> The geometry I am trying to produce is a thin walled (.060
in.)
> pattern. The walls are approximately 11.50 in. tall and are
of a
> complex surface design. With the wall geometry being this
thin it has
> proven to be a challenge to produce and drain. We have a SLA
5000 and
> are using SL5195 resin. I have been able to achieve a minimum
wall
> thickness of .018 in. per side leaving .024 in. for draining
but have
> had little success in draining the part. I have been working
with the
> Stereolighography process for quite some time but have not had
the
> opportunity to produce any QuickCast parts until now. I am
working
> with the 3D Systems FSE's testing the boundaries of the
QuickCast
> process. They have concurred that this is not an easy part to
> produce. What a way to begin. Understanding the QuickCast
process
> such as I do regarding overcure issues, hatch type parameters,
laser
> beam technology, etc. we are presented with a couple of
questions.
>
> 1. What is the smallest geometry thickness anyone has
produced
> with the QuickCast process?
> 2. Has anyone produced an actual casting from this thin
of a
> pattern?
> 3. Is the best way to drain this part to use a centrifuge
or is
> there something else?
>
> Any help with these questions would be appreciated.
> Thank you.
>
>
>
> For more information about the rp-ml, see
http://ltk.hut.fi/rp-ml/
For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
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