RE: Is it possible to use RP systems to product production parts rela tively cost-effectively???

From: Scott Tilton <>
Date: Wed Jan 07 2004 - 16:14:30 EET

Bravo Bill!

Very well said!

I agree with just about everything in your message.

Some of your points in particular really struck a chord with me.
Whenever I talk to people about "direct manufacturing" (which is a term I
prefer to rapid manufacturing . .but that's a tangent for another
I always end up saying to them that if you back far enough away from them,
they really aren't any different than "conventional" manufacturing methods.

Effective design takes into account a knowledge of the materials and
processes used to make the part in question.
This is true for machining, forming, molding or whatever.

How many times has a designer come up with something only to have a
machinist come back and tell him what features are going to be difficult, if
not impossible for him to make?
The same is true on RP machines: they have limitations too.

A difference is that the conventional manufacturing processes are understood
to a much higher degree by a vastly larger number of people.

I better get off of this before I type myself in circles.

Until the capabilities and limitations of the various direct manufacturing
processes are more widely known, having a team of designers and fabricators
familiar with the specific RP technology intended to be used is definitely
the way to go. A couple of my design engineers here have grown to know the
general capabilities of our SLS machine pretty well. And consequently they
can design to the process much better than your average off the street
design engineer.

That being said, everything is still relative. They will still sometimes
ask for the impossible or even sometimes underestimate the capabilities. So
relative to the design engineer population as a whole, they are very
knowledgeable, but relative to the technicalities of RP, they still have a
good ways to go.

Keep up the good comments Bill ( and actually Johnn Kerr's reply too for
that matter )

Scott Tilton

PS ... although it depends on your definition of "direct product" I think
there are quite a few folks out there generating "direct product" right out
of their RP machine.

Particularly some of those ever growing number of Stratasys users out there
who are filling their own little niches but not necessarily advertising it.
That too is probably a topic for another tangent.

 -----Original Message-----
From: Bill Richards []
Sent: Tuesday, January 06, 2004 11:17 PM
To: Pacholski, Mike [SAA]
Cc: ''
Subject: Re: Is it possible to use RP systems to product production
parts rela tively cost-effectively???

Hi, Mike,

        This is a loaded question, for sure.
        The short answer is, "Yes." There are a number of companies that
on rapid prototyping systems as the core of their production cycle.
        However, I don't know of anyone who generates direct product right
of the RP machine.
        But as Larry Blasch stated, the devil in the details. There is a lot

more to it than that. As I stated above, you MUST approach rapid
prototyping as a system, not just looking at the machine. And the key
thing that makes rapid prototyping work are the people working the
system, not the rapid prototyping machine.
        You need to understand what types of RP equipment will best serve
needs. You need to understand how to design for the machine and your
products. How to pre-process the files -- some machines are more
tolerant of imperfections in the STL generated from CAD models than
others. How to post-process the pattern that the machine produces.
        Your best bet is to use the machines to produce a pattern for
investment or sand castings, or to use it to create a green part for
sintering. If the majority of your parts are large, the systems that
can handle the larger sizes are the SLA and SLS type machines.

        Though the easiest way to describe a rapid prototyping machine is to

explain that it is like a 3D printer, one must NEVER forget that these
machines are NOT 3D printers! An RP machine is a piece of capital
equipment (just look at the price tag), and it requires just as much
skill and time to prepare and operate as a CNC or any other piece of
equipment in the tooling room.
        My personal opinion is that the person who is designing should also
the operator of the machine, or at least be in charge of the people
that are running the machine. The more feedback the designer gets by
dealing with the patterns, the better the designer can create models
that answer any of the quirks of the RP machine in use.
        RP machines are cantankerous things at best. They only like to work
when they're being watched. However, get an operator/designer or a good
team that understands what it takes to move the RP system from design
to casting -- these things can really shine!

        RP systems work best in an environment where a design must be
reproduced with many variations, precluding the possibility of mass
production. Cell phone body designs are a pretty good example of this.
Cell phone manufacturers need to produce new designs two to three times
a year just to stay ahead of the competitors and changes in style.
        Jewelry is probably an even better example.
        If you need to create a lot of short run production, or you need to
create custom designed objects, then RP technology might just help.

        The best advice I can give you is to forge a partnership with a
service bureau that uses the type of equipment that you want to
evaluate. Explain that you are looking into bringing RP technology into
your business plan, but aren't ready yet. They'll be more than happy to
have your business.
        And keep in mind, that once you purchase your own equipment does not

spell the end of this partnership. You can still rely on the service
bureau when you have an overflow of work, but not enough to justify the
purchase of another machine. It will work the other way too: when the
service bureau has a customer who needs casting work done, guess who
they can turn to.
        This will give you RP capability, without having to make the initial

purchase without knowing whether or not this will work for you. One
thing to remember, though, is that the service bureau has other
customers, and they may not have the capacity to take as much work as
you may want to give them. Or to respond to your needs in as timely a
manner as you want. This actually happens fairly often. That's usually
the point where it's time to purchase your own machine.

        One point you should remember: Rapid prototyping is not as rapid as
you think it should be, but it's still faster than traditional methods.
And if you really needed it done yesterday, you'll have to wait until
they invent quantum prototyping so that they can take tomorrow's
backorders and get them delivered last week.

        Bill Richards
        Virtcon Design

On Jan 6, 2004, at 12:36 PM, Pacholski, Mike [SAA] wrote:

> So this brings us to the final question, can these (or any RP
> process) be
> turned into cost effective production method? Will a large number of
> parts
> and RP systems running time substantially reduce cost (larger material
> purchases, long machine run times, ect..)? Should we consider further
> investigation into this? Your comments are greatly appreciated!!!

Received on Wed Jan 07 16:02:14 2004

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