This is an interesting topic to me.... while at DEC, I wrote
a program for our surface plate/vision tool (I'm a EE, so forgive me
for mangling the correct name of this system) that inspected parts
for coplanarity in waffle trays. I don't remember the name of the
system, but it had a camera mounted over a 4'  x  4' x 1' granite surface
plate, with the camera being under software control.

I indexed the plane of each part by taking 3 measurements off of
the component body, then using that as the reference plane, stepping
around the part measuring skew and coplanarity. The neat thing
about this (at least I thought so! :-) ) was the ability to measure without
removing parts from the trays. It worked well as an Incoming Inspection
tool, to gather data to work the root cause problems with the supplier.
It was fairly slow, and would not be suitable as an in-line screen
(which you wouldn't usually want to do anyway!). The program then
stepped to the next part in the tray, found the appropriate edges
and started all over again. It would work its way through the tray,
and datalog and plot results. Very handy to get a suppliers attention
with!

I have no idea where that piece of gear went. I do remember it came
on it's own tractor trailer (there was nothing else in it!) and we had
to scramble to get a BIG fork to get it off of the truck!  DEC scrapped
a HUGE amount of stuff in it's implosion period (including ME, I guess :-) ).

John
(Ex- of DEC Workstation Manufacturing, Albuq. NM)

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