Rapid Protyping and advanced mold making


Andy Carlson
 

I have a first hand report on a roundhouse brick wall
in HO produced in injection molded styrene. The bricks
were reported to be the finest Terry Wegmann has seen
in plastic. The walls were CAD 'ed by the increasingly
productive Jim Booth, and the mold maker cut the
tooling with a focused laser cutter into the metal
mold.

Terry has been working with a Laser Tooling maker for
2 years to make molds for producing styrene SP
Overnight doors (and 2 other improved Youngstown 10-0
6' doors), the mold maker patiently waiting for the
CAD data to proceed.

I saw at Terry's work a large scale switch stand which
went from CAD to SL to wax to investment part. No hand
prototyping. Real Cool!

I don't see much time passing before complete laser
cut injection molded freight car kits (& RTR) becoming
available. The implications can be enormous- imagine
freight car kit construction returning to our shores!
-Andy Carlson
Ojai CA


Jon Miller <atsf@...>
 

The process is too slow to compete with resin and injection molded plastic
but is great for producing masters, either for resin kits or for ceramic
tooling inserts.<
I know nothing about ceramic tooling inserts however I'm wondering if
the tooling (for injection styrene) would hold up for say 500 to 1000 kits?
Is this a range to make a styrene kit (using this process) profitable?

Jon Miller
AT&SF
For me time has stopped in 1941
Digitrax, Chief/Zephyr systems, JMRI user
NMRA Life member #2623
Member SFRH&MS


Charlie Vlk
 

While the CAD/M and laser technologies are making advances, a large part of
the expense of tooling is still in the mold base and fitting the inserts to
it.
The marketing of kits is not related to the cost of the tooling,- it is a
function of the demand for kits versus assembled cars. Even buildings are
now coming built up.....this is not because labor is cheap in China (it
still costs more to assemble and ship assembled parts than package kits) but
because (most) customers in the marketplace want to buy them that way.
Rapid prototyping has its most promising application in the creation of
masters for short production run kits.... something in between today's resin
kits and Intermountain / P2000 . I have been working with a company that
has a new technology machine that has the resolution to build Z scale rivet
sized detail into an acryic plastic part. The process is too slow to
compete with resin and injection molded plastic but is great for producing
masters, either for resin kits or for ceramic tooling inserts.
There is all sorts of good stuff coming and the technology is helping make
possible projects that would have not been possible five years ago!!
Charlie Vlk


Charlie Vlk
 

Ceramic tooling is used for some injection molded plastic kits that are
commercially available in both HO and N Scale.
I've heard that the Beyers (???) horses are molded from ceramic molds made
by the same company that supplies tooling
to a couple of manufacturers that make those kits.
The finish and fit of the molds can be pretty good..... although AFAIK
ceramic tooling has not been used for rolling stock.
The tooling isn't good for large numbers of shots, but certainly enough for
one-railroad prototype freight cars of specialized
interest. And if you guess wrong new inserts can always be made to replace
the worn-out ones for a fraction of the cost
of having a damaged aluminum or steel insert repaired or replaced.
Charlie Vlk
Railroad Model Resources