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Moore diamond turning lathe

Posted by Elliot Burke
on 2003-01-30 21:52:46 UTC
Just got back from Photonics West in San Jose. Several diamond turning
lathes were shown, the Moore one looked exceptionally nice.
It had an air bearing 6000 rpm spindle, which was mounted above a slide
parallel to the spindle axis. The tool (single point diamond) was mounted
on the cross slide. The slides were hydrostatic (200 psi), about 1 foot
wide and a couple of feet long. Rated at 2 million lb/in. 9" swing, 6"
vacuum chuck on the spindle. This was all mounted on a grantite slab about
4 feet square.

1 Microinch accuracy, and a bit better than that in a few of the specs. A
sub arcsecond rotary table was available too, I think this mounted on the
cross slide under the tool.

This machine is intended to make precision mirrors and molds for lenses.
There are some crystaline materials the diamond can cut, but it is pretty
tricky to cut glass. Depth of cut cannot be more than a micron or so, or
the tool will be ruined, or so I've heard.

They have some other stuff too, but I think it was too big to lug out to a
little optics show, like the machine that cuts the facets for molds for
plastic retroreflectors.
One of their machines has a hydrostatic bearing for the spindle, I was told
the pumps were bigger than the lathe.

An exceptionally nice little lathe! There was probably a lot more I could
have learned about machine tool design if I would have had the wits to stop
drooling and ask more questions. Looking at something like this make we
want to scrounge up a pump (or use house water pressure?) and make a
bearing.

The piezo electric actuators were interesting too. There was one device
were the piezo stack was inside of a thick metal ring, almost elliptical.
The piezo stack ran along the major axis. The movement along the minor axis
was magnified. One of the larger of these had several mm motion, and was
used for damping motion on helicopter blades. The small ones had a few 10s
of microns of motion. A clever trick, since the ring could be made to keep
the stack in compression. I will FEA this device and see if I can figure
out how it works.

regards-
Elliot B.

Discussion Thread

Elliot Burke 2003-01-30 21:52:46 UTC Moore diamond turning lathe