For those that want to know more about about this, read on, otherwise <del>
There are several RP (rapid prototype) processes, the most common of which
is stereolithography or SLA for short. The process goes like this -
design engineer creates 3D solid or surface model in a 3D modelling package
like I-deas, ProE, SolidWorks, etc. The model's 3D surface data is output
in a .stl file.
The prototype house imports the .stl file into their system, where they
position in the part(s) and add supports ( like little pillars) that are
needed during the construction process. The pre-processor software then
creates cross-sectional slices of the parts(s) that are anywhere from
.005-.007" thick.
The SLA machine consists of a UV laser, an aimable mirror optical system, a
tub of UV cureable epoxy resin, and a height indexable platten within the
tank. The platten starts off .005-.007 below the surface of the resin, and
the laser "draws" the first cross-sectional slice on the resin which cures
that section. Platten indexes down on thickness, a wiper moves accross to
ensure resin coverage, and the next section/slice is "draw". Repeat until
enitre parts is "drawn". Platten is raised, part is removed and post cured
in an oven, the supports are removed, and the surfaces are sanded to remove
minute steps created by the process.
There are several variants to this process. One uses powdered thermoplastic
that the laser fuses (SLS selective laser sintering), another uses either
starch or plaster powder and an inkjet printhead printing a binder solution
instead of a laser ( Zcorp). This process can actually be used to make
plaster molds for soft metal casting - the part geometry is subtracted from
a block in the 3D software to create the mold blocks which are then RP'd and
used to cast the metal part. http://www.zcorp.com link for Z-cast.
Prototype place we use most is http://www.tth.com/ - software we use is
I-deas http://www.eds.com/products/plm/ideas/pdf/coremod.pdf which is
probably the best package for complex, organin shaped products. Ford Motor
uses a customized version of I-deas for complete platform design - the .pdf
above has an image of an engine block modelled in I-deas....
Mark Sedlack
Millenium Development Corp.
OROC
Cuyahoga Falls OH
66 1600 http://home.neo.rr.com/mark2000/images/datsun1600/
77 280Z http://home.neo.rr.com/mark2000/images/datsun1600/Z.htm
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