Rapid Prototyping from one who has done a bit

sryn.dump <sryn.dump@...>

While this might be seen as a slightly “off topic” reply I’ll start by
saying that Rapid Prototyping allowed me to produce an ACCURATE Southern
Railway SU Boxcar in N scale. So far the big commercial guys haven’t done
this one in N scale.

Let me start by stating that I’ve “done” some Rapid Prototyping- for N SCALE
and HO.

I used AutoCad Inventor. This is a 3-D software package.

My drawings were done in prototype dimensions. For the final product they
were scaled down to N scale.

This meant that I had to consider a few things during creation. I also
built an HO doghouse. (Southern Railway Prototype)

I’ll discuss the doghouse. If you write to me off list I’ll send you a link
to a picture of it.

During creation the RP machine (I used a Perfactory) will takes file and
re-create the model just designed it. That means that if you go with
prototyp thickness you may have some thin areas subject to deforming. They
can also be fragile. I “beefed up” the interior to make the walls stronger.

Yes the “smooth surface” can be a bit problematic. Most folks get around
this (to some degree) by using a build platform (the orientation to the base
that the model is built on) to alleviate some of the “stair stepping” that
can occur.

Building actual models using the perfactory one must consider how the
product will be handled. The doghouse model I did each one on the machine.
I also created a tool box that was INSIDE the doghouse with ALL detail. The
modeler simply sanded the bottom until the supporting “build posts” broke
free and the tool box dropped out.

BTW, I also took the same file to one of the “powder” 3-D printers and was
disappointed it just could NOT get the resolution of the Perfactory. It
looked like the sides of the dog house were not sheet metal but rough

The Perfactory model was acrylic and thin. I doubt that it will sustain a
drop to a concrete floor with the tender dropping on it.

I sold a few of them to SRHA members and they were appreciated. I hardly any
profit on them since I paid for the time and materials on the perfactory.

For my N scale box car I used it as a master and made an RTV mold and cast
in resin.

The N scale car (even with build platform shifts) required a bit of sanding
on the roof but then it IS an accurate roof for the car and the panels have
the correct stamping. I was also very happy with the correct Hutchins ends.

Now all of that being said, I’ll say that RP is a viable way of creating
many types of models. Costs are not your LHS shake the box prices. Some of
my “potential” customers thought my prices were high even though they could
not get an accurate Southern doghouse retail.

Yes, learning the software is more than a challenge. It is probably more
than the average computer user will ever attempt. The cost of the software
is NOT CHEAP. Time and materials on a machine like the Perfactory are not
cheap (yet).

Again, if you have specific questions etc, I’ll be more than happy to reply.
I can even send BMP files of portions of the drawings I’ve done if you ask

Gordon Andrews

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