SLS LaserForm ST100 vs. RS2... Your Opinions Please

From: Jim Williams (
Date: Thu Jul 05 2001 - 17:22:06 EEST

Hello to All,
This request is particularly focused to users of DTM's LaserForm ST100.
More specifically to users who are producing parts, not mold inserts. Even
more specific are parts that do not have a flat down facing plane. The
reason is it's been Paramount's experience that flat down facing surfaces do
not require support structures using LaserForm. Therefore, making these
parts is quite simple relative to parts that have a complex surfaces none of
which are flat to use as the down facing surface. It has been our
experience complex down facing surfaces require a support structure to
eliminate sagging and warpage during the multiple furnace phases. A further
consequence of the processing change from RapidSteel 2.0 to LF ST100 is
internal areas that previously could have been packed out with coarse
alumina to support the part during sintering may be impossible to produce
because of the necessity of cutting and machining support structures. At
the very least more time consuming and costly.
In Paramount's opinion this is a direct consequence of the different
processing developed for LaserForm ST100 (LF) vs. RapidSteel 2.0 (RS2). RS2
required (2) distinct furnace cycles. The first ~24 hour cycle was the
sintering phase. To prepare for this phase we packed a coarse alumina
carefully and completely, surrounding the part, including internally. This
was our support as the part was phased from green to sintered to prevent
warpage. The next phase was the infiltration phase. We removed the crucible
from the furnace and repacked the part. Because the part at this time was
rigid as a result of the sintering phase in virtually didn't need support.
Adding to this, we were able to re-orient the part to achieve the most
effective infiltration position. We surrounded the part in a fine alumina
to direct the bronze infiltrant to the part. As we experienced last year
during participation in DTM's beta for LF the new furnace process combined
both sintering and infiltration into (1) furnace cycle. In other words you
did not remove the crucible post-sintering and repack the part in fine
alumina as we did with RS2. The LF part is supported mechanically by adding
supports, thus replacing the coarse alumina and surrounded with fine alumina
to control the flow of the infiltrant. Saved time, but at what cost?
First, if anyone has experience to the contrary I'd appreciate knowing that.
If however, your experiences are not unlike ours then the question is, are
you using any special software applications to design your support
structures? I've heard, but unconfirmed, Bridgeworks is being used. If I'm
not mistaken Bridgeworks is the tool used by SLA people. SLA parts have a
lot of support structure. When doing SLS powder metal parts removing
support structures adds a great deal to the cost and time. As an example in
Paramount's 2+ years in working with LF's predecessor RS2, 99% of the time
we never had to design support structures. In the rare instances we needed
mechanical support it was usually because of the part frailty (small and
difficult to handle).
At the SLS UG 2000 conference, during the LaserForm break-out session I
attended, DTM personnel confirmed that parts which were previously possible
with RS2 may not be as friendly with LF ST100. What's happened since Oct
2000? Who has had success using LF ST100 making complex parts? I would
appreciate hearing from you. If you have any experience that is different
then mine I'd like to hear from you. Call me toll free at 1-888-RPTOOLS or
directly via email <> .
In 1998 when RS2 was released for beta I organized a user group of the then
~(6) RS2 users. We shared experiences and ideas which hopefully lead to
continual improvement for the individual users, their respective companies,
as well as the industry at large. Paramount has remained steadfast in it's
belief that processing metal parts with RP technology is a significant
achievement for prototyping, but more importantly for small lot
manufacturing. Further it invites a new paradigm of design innovation to
make parts that are totally unconventional in the world as we see it today.
I am extending the same invitation as I did in 1998 to LaserForm ST100 users
and RS2 users (for those of us that still exist) to join me for a special
SLS powder metal UG. Place and time to be determined.
Because of my experience in receiving a lot of unnecessary email as an RP-ml
subscriber I unsubscribed 2 years ago. Please reply to my personal email
address. Thank you and happy sintering!

Jim Williams, President and CEO
Paramount Industries, Inc.
2475 Big Oak Road
Langhorne, PA 19047
215-757-9611 x229
215-757-9784 fax

Don't be seduced by the noise from their mouths. Pay close attention to the
actions of their feet.

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