From: Mark Glusker <glusk@mechcad3.engr.sgi.com>

 I just received some stereo lithography parts last week that were made of
polycarbonate.  It is finally possible to use that process for more than
just verifying the shape of objects.  However, if you wanted to replicate
a cube (I assume you mean a Rubik-like mechanism)  you would need to do
lots of post-finishing to remove the "raster" ridges from the parts so
they will move smoothly against one another.  This post-finishing is done
by hand and will certainly affect your final tolerances.

 I use ProEngineer (on a Silicon Graphics workstation, naturally) which
can automatically generate an STL file, the standard data format used by
the stereo lithography vendors.  There are lots of vendors around here,
and several have relationships with prototype die casters for limited
production runs of parts (5 to 100 pieces, typically).

  {At this point, Mark offered help; however, since the help was a
personal offer to me, I don't want to post his comments directly.  -nb}

{snip}

 ... I could go on for quite some time on this subject! 

 There are similar digital processes for replicating flat metal parts from
a CAD file, with similar economic tradeoffs, in this case related to
perimeter-per-area of part.  That would be a great way to replicate a
missing piece of a mechanical calculator,... {Here, Mark's helpful
comments were welcome, but off-topic for this List. -nb}
Regards,

Mark

 

|*  Nicholas Bodley   *|*  Electronic Technician {*} Autodidact & Polymath
|*   Waltham, Mass.   *|*  -----------------------------------------------
|*  nbodley@tiac.net  *|*    When the year 2000 begins, we'll celebrate 
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