'99 conference & confused - rapid milling?

From: T Schuett (todd@creat.com)
Date: Sat Apr 24 1999 - 17:11:37 EEST

>Sure, everything cost money but the amount of money the RP industry is
expecting is pretty high. >The SBs have realised this and have dropped their
rates and are seeing benefits.
>It is high time now that the OEMs too realise this and start reducing their
prices to affordable >levels.
>RP per say has limited application and with the metal RP coming to fore
coupled with enhanced >accuracy and speed, I think it is just a matter of
time (my guess is about 2-5 years) when the RP >gets into the main
production lines. When I say RP, I mean the technology and am not
restricting >myself to the SBs.

I'm confused by the overall tone of the correspondence on this list that I'm
new to, so bear with me...

Is the purpose of RP to make prototypes quickly and accurately or is it
technology for technology's sake?

There seems a real absence of discussion of enhanced use of traditional (?)
technology like CNC milling within this group! Many in the industry
approached me during the show to discuss their newfound respect for real
high-performance CNC milling of models, citing the better finish off the
machine, less handwork, greater resulting accuracy and the generally
equivalent speed. The unlimited choice of materials seems to make
prototypes that better represent production parts. Overall, rapid milling
seems to be the method of choice for those with that choice.

Does that mean that I don't respect the high value of other RP techniques
and their need to evolve into more useful tools? Absolutely not. Rather, I
encourage the use of all available technology to get the job done quickly
and accurately, at a profit. Certainly there are significant advantages to
many RP techniques for many parts with complex buildups or structural

Still, I think the intense discussions on choices and competitive methods
within this group are lacking acknowledgement of "best methods." I expect
this will draw many remarks that traditional techniques do not require
discussion, but the clang about CAD/CAM, as an equally established tool,
convinces me that there is still a lot to be said of the ongoing evolution
of so much traditional stuff.

Many have stated concerns over the future of the industry. No surprise
here! Much of the tooling industry in "rapid" and non-rapid (like molds and
dies" are concerned where it is all going. I can see a convergence in
plastic injection mold making with the "rapid" industry because my customers
keep improving on their deliveries and techniques. They are using
well-known techniques of milling and EDM to get more aggressive about making
prototypes. Either aluminum or even hard P20, etc. are commonly being used
to build prototypes in just a week or two. My customers now tell me that
the only difference in a prototype and a "hard" tool is the complexity of
the mechanism and the number of cavities. They are now building cell phone
part "prototype" molds of P20, capable of millions of parts, in less than 2

Will this put you out of business? Not likely unless you're faint-hearted.
You and your business will have to evolve to offer different services and/or
other advantages, though. More creative design service integrated with
visual models seems to be the logical separation of prototyping from the
engineering and technical service offered by a mold shop. Still, that
convergence of prototyping with mold shops will continue, say I.

So back to the milling and technology for its own sake...

One of the many notable things frequently discussed on the floor of the show
was the speed, finish, accuracy, and choice of materials offered by CNC
milling. Many have a bad taste for it because they haven't seen the speed.
They think 60 IPM is fast for CNC milling. That is way wrong!

Defiance Innovations was showing a small and inexpensive
(relatively -$70,000) CNC machining center that is arguably the fastest in
the industry. We aren't talking fast in rapid traverse rates, but rather
fast in SUSTAINED FEED RATES. Because of quality design and look-ahead in
their CNC control, they can program for 500 IPM or so and sustain it more of
the time than anyone. This means dramatically faster parts than most expect
from CNC milling. The speed is also used with finer stepovers to virtually
finish the parts right on the CNC. Defiance Innovations also offers smaller
bench mills that are deceptively fast and accurate for their low $35,000
starting price tag! They still use the same feedrates as the higher priced
models above.

My own company, Creative Technology Corporation, offers retrofits and hybrid
CNC mills, again offering sustained higher feedrates. One prototype service
on the floor had no complaint of his CNC speed, generally using feedrates
around 60 IPM on large Haas machines for most all his prototypes. He was
floored to learn that he could speed things up 3 to 5 times or more just by
a CNC control change on that same machine! We have a lot of experience
doing that for people in the rapid prototyping trade for about 15 years.

Successful rapid milling relies on fast and efficient cutterpathing. We
aren't just talking about crunching the numbers faster, but also taking less
human intervention. The HUMAN LABOR to cutterpath CNC parts can seem like
one of the biggest hurdles. PTC's Pro/Man can do better than ever before
for both speed and reliability. Still, it can be complicated to learn and
use. A real secret weapon can be Sescoi's WorkNC. It is only a 3-D
cutterpathing package, working with all CAD and CAD/CAM packages. WorkNC's
benefit is that it takes almost no labor to make your cutterpathing choices
and cut 3-D parts reliably! It can be counted on for good, gouge-free paths
day in and day out. While other companies are aspiring to this noble need,
they have a 10 year track record of success. Their fast and accurate
cutterpaths can make the difference in your success or failure with rapid

SLA is the stuff dreams are made of. Parts magically emerge from chemicals
with light, smoke and mirrors. That's not cynical, it's a true statement!
What more could we want? The other technologies each represent new and
innovative ways to solve many specific challenges in our trade. Still, we
mustn't forget our mandate to run our businesses for a profit! We must use
the available tools to push the envelope, not only of technology, but also
the service and profit envelope. Don't ignore the evolving changes in your
old technology that can make it key today! When you can offer more accurate
and faithful prototypes faster, with less manual work and a lower overhead,
this is the stuff business dreams and success is made of!

Todd Schuett
Creative Technology Corp.

P.S. I sincerely want people to use the tools they have to the best
advantage. This was not intended as a commercial. That's why I didn't list
web sites right with the text. Still, some will want more info, so I ask
the others to forgive the following... If you want more information on any
of the stuff mentioned, Defiance Innovations www.defianceCNC.com, Creative
Technology Corporation www.creat.com, Sescoi WorkNC www.sescoi.com.

For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/

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