Model Forum / General / Models / August 2007

The version I saw used something that looked like a tank of liquid
polyester resin that it solidified into the object.

Pat

I think you're not thinking out of the box.

Builder makes several parts from the machine that comprise a kit.

But you'd still have to paint it... now assuming it was an aircraft, and
they managed to place the whole cockpit into it during manufacture...
you are really going to have some fun painting the inside through the
cockpit opening (although I've done this in a few occasions)
There's also the fact of that layer thickness of .01 inch they mention;
that's not good enough to manufacture a really super-smooth surface,
like is needed for a car body or a canopy, although it might work for a
tank.
If detail fidelity goes way up, you could still manufacture
sub-assemblies via this method that would be glued together like a
conventional resin kit. It seems to be a lot of trouble to go to to
manufacture a limited edition model though unless you can assure
yourself of fairly numerous sales. One of the smaller aircraft models I
have is a 1/72 scale Ba-349 Natter rocket fighter; that's probably
around 4-5 cubic inches of material, so actual material cost using this
process would be $4 - $5, which is pretty reasonable; you could sell
them for $10 each and make a profit. But consider the number of
man-hours that would go into  writing the program that the machine will
use to make them to the level of detail of a injection-molded or resin
cast kit, and the economics don't look as good unless you sell quite a few.
On small things this may work, but as the size starts increasing, things
don't look as good; a 1/72 scale B-17 is going to be around 50 cubic
inches of material or more,  so now cost is up to $50 just for materials.
Once you go beyond that size things go completely off the deep end as
far as material cost go due to the square/cube law in relation to size
and volume goes... a hypothetical 1/32th scale B-17 now ends up costing
several hundred dollars for materials alone even if it's all made very
thin internally.
There's also the problem of how you get the excess unsolidified forming
production material out of the inside things of like the tires, where
there is no obvious way for it to be poured out.
That could get expensive fast, and drilling holes into the model to
drain the unsolidified material out of it sort of defeats the purpose of
making it in one piece.
I don't think we'll see this being used in a large scale anytime soon
for making models, as the technology doesn't seem to be a great leap
over what we have when it comes to effort and production cost versus price.
At best, it might be used for quite small models where someone sells you
the files needed to allow your home replicator machine to make a model
of something. But I think they are going to need to get their  fidelity
level up a order of magnitude to around .001 inch thickness per layer to
make it competitive with injection molded or resin cast kits.

Pat

Uh...the future is NOW...

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