From: Roger Spielman (
Date: Mon Dec 17 2001 - 19:10:48 EET

Hello all:

Good point Marshall. This really is inevitable, and necessary to the
evolution of a "neural network" for Rapid Manufacturing. You touched on the
cornerstone when you mentioned material properties. Unfortunately, very
little work has been done (that is available) on this subject for many
processes other than SLS and SLA. By that I mean information that can be
used in a materials database or selector. Another aspect will be the ability
to determine which process (including turning and high speed machining)
would be most appropriate for a given geometry. With all the great work that
has been accomplished in the past ten years or so we really are still on the
ground floor, and in my opinion, looking at a pretty bright future.


Roger Spielman
Regale, Inc

-----Original Message-----
From: Marshall Burns []
Sent: Friday, December 14, 2001 9:48 AM
To: 'RP Mailing List'
Subject: Re: STONE SOUP

From: "Bibb, Richard (PDR)" <>
> The problem with trying to come up with a system that evaluates RP systems
> is that it is in danger of comparing apples and bananas and not apples and
> apples. I suggest that a practical way forward is to compare RP system
> capabilities to product development objectives rather than comparing all
> systems to each other.

    One of the exciting things about this whole field of technology is that
there are so many different ways to accomplish its objective (to make a
solid object from a digital description and raw materials). I believe the
issue proposed by Paul Finelt in his "Stone Soup" e-mail has an even greater
long-term importance than deciding which *machine* to buy or use today.
Future machines will incorporate a variety of processes and the software
will have the challenge of determining which *process* to apply to creating
any particular shape and structure found in the CAD data.

    Perhaps a step forward for working on this problem from where we are
today is to develop a database of technology capabilities in terms of a
multi-dimensional matrix of materials, material properties, resolution
(in-layer and z), accuracy, solid formation rate, results repeatability vs
need for experienced operator, etc., etc. There's a wonderful book by M. F.
Ashby called "Materials Selection in Mechanical Design" that gives dozens of
two dimensional selection grids on the basis of many pairs of
characteristics. A computerized, multi-dimensional version of this technique
could help a user zero in on a desired domain of capabilities and the
processes/machines capable of working in it.

Best regards,
Marshall Burns
President, Ennex Corporation
Los Angeles, USA, (310) 397-1314

For more information about the rp-ml, see

For more information about the rp-ml, see

This archive was generated by hypermail 2.1.2 : Fri Jan 04 2002 - 09:58:19 EET