RE: [rp-ml] Super Large RP or AF

Two passes for foam? The second to melt or apply solvent doses to densify
the foam surface sculpturally? Actually a harsh material atmosphere to work
in, water base materials are more enjoyable.

Working directly with concrete even EPS-concrete would at least smell
better. EPS concrete (made with recycled styro products ground into
"gravel-beads") actually is light-weight enough to form freely in air
without collapse. Methods to directly foam portland cement paste (without
pre-foamed content) seems to be another material in progress, another
material potential for experimenters with budgets.

I'm trying to work with low budgets, to compete in sculpture. Have you guys
looked at "3D camera lucida":
http://www.midcoast.com/~bo/CADMERA.html

On Jun 21, 2006, at 6:30 PM, Charles Overy wrote:

What about a super /FDM/Solidscape extruding metermixed rapidsetting
urethane foam. A 2nd gantry/head net shapes the extrusion with cutters.
(top and sides or, in a more advanced version, adds detail to the
extrusion.)

Charles

 Charles Overy : Director of Engineering
 lgm :: architectural visualization
  http://www.lgmmodel.com
  cwho@lgmmodel.com <mailto:cwho@lgmmodel.com>
 970.827.5274
 800 448 8808

-----Original Message-----
From: owner-rp-ml@rapid.lpt.fi [mailto:owner-rp-ml@rapid.lpt.fi]On
Behalf Of O. Makai Smith
Sent: Wednesday, June 21, 2006 2:48 PM
To: rp-ml@rapid.lpt.fi
Cc: John Brock; bo@midcoast.com
Subject: Re: [rp-ml] Super Large RP or AF

Hi John;
Right you are! We used primarily that method for making the MGM lion:

http://www.kreysler.com/projects/mgmlion/lion.htm

and other large figures we did awhile ago. Though we do very little
slicing now. The bear:

http://www.kreysler.com/projects/Blue%20Bear/bluebear.htm

was done using milling (of molds). The aligning/gluing introduces
enough slop (and takes so much time) that we tend towards milling out
the foam positives or molds directly (and segmenting them as necessary
to account for the complexity of form). Internal features, of course,
are not possible this way without some effort, but we have yet to build
a large enough additive machine to make our gantry mill obsolete!

I'd like to though. I think the robotics is the easy part (maybe using
EMC for instance?):

http://www.linuxcnc.org/

But the build material, not so much. Berok's using fast-cure cement;
there are polyurethane foams. I am interested to hear about what
thoughts others have about materials to deposit (and also on control
systems, and mechanical platforms...I see a lot of gantries, but there
are many other ways to move the nozzle).

Makai

John Brock wrote:

Hi Bo:
   For big stuff, think "subtractive" instead of "additive" RP. Your
model can be milled in slabs from 20# foam on a large gantry mill. The
sections can be pinned together, then lost detail re-carved, then filled
and sealed with Bondo and primer. This big model can be used as a plug
to make a mould. Then using the mould you can lay up as many as you
need in Fiberglass. This is how Disney Imagineering gets 25' tall
fiberglass Mickeys, etc.

John Brock

Thanks good people, I really appreciated the update on capabilities
of rp
today... I must say I'm surprised no one seems headed in the
direction of
trade off towards low cost rp with low accuracy... Not that it is
easy. For
the price of a life size, high detail foam bovine, it seems I
actually built
a giant 60 ft or 20m snapping turtle with a garden inside: http://
www.midcoast.com/~bo/TurtleGarden.html . I'd still love to get work
on a
derrick supported rp system using concrete. I think much more must be
possible at a dollar per pound or a euro for a kilo range, at least
by use of
fire-wire cameras with renaissance-ciaro-scuro methods and concrete
batcher,
which i kind of used on the turtle... Turtle is mostly soils and
less 1$ US
per kilo when you subtract associated landscaping and 60+ meter
wetland I
personally dug and leveled for them with a mini excavator.)

Bo
Atkinson
Received on Fri Jun 23 10:35:46 2006