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 Wed Jun 21 23:00:29 2006