RE: [CAD_CAM_EDM_DRO] re:RE: Epoxy Granite

Elliot,
SPDT of borosilicate, Cervit, Zerodur, and lots of materials is very
successful see;
http://www-eng.llnl.gov/lodtm/pdf/HI_SPIE_DT1.pdf

I have no illusions of reaching LODTM 1/25 wave or POGAL 1/60 wave accuracy.

I would like to be able to create mirrors from .3 to 2 meters to at least 2
waves (with figure) and traditionally polish to finish of 1/10 or better. I have
laser displacement sensors that will easily get me to my goal (lamba/2 @635nm).
The trick is going to be integrating the LD Sensors with DSP's to move the
cutting head fast enough to keep the correct depth, while moving linear motors,
reading laser interferometers, rotating the cutter on ROC, controlling spindle
air pressure/speed, maintaining environment, and all the while hoping that I
sized the UPS/generator just right in case the power goes! :)

Whew! Why am I doing this? Oh yeah... for a telescope and because I've always
wanted to.

Having said all that, if SPDT is to finicky then I'll fall back to grinding
which will achieve the same results only I don't get to thumb my nose at those
guys at Stewart Observatory (insert Monty Python taunt here). :)

Jack Hudler

-----Original Message-----
From: CAD_CAM_EDM_DRO@yahoogroups.com [mailto:CAD_CAM_EDM_DRO@yahoogroups.com]
On Behalf Of Elliot Burke
Sent: Monday, February 27, 2006 7:53 PM
To: CAD_CAM_EDM_DRO
Subject: [CAD_CAM_EDM_DRO] re:RE: Epoxy Granite

Jack,
Are you really going to try to single point turn glass?
I've read of experiments along that line, not very successful.

Grinding on the other hand can give a pretty good finish. Determanistic
microgrinding will give a finish that needs only a light polish.

Optimax has patented a process that preserves the shape of an aspheric
surface while polishing it. I don't remember the number but you could call
them and ask.

regards-
Elliot Burke