RE: [CAD_CAM_EDM_DRO] Epoxy Granite

Harko,
Because the mirror is so thin 1.75"; I'm turning it in its mirror cell.
This cell is a functional part of the telescope on which the mirror is attached
axially to 36 actuators pads and radially at the 300 mm hole cored in the
center. The actuators are then used to flex the mirror to compensate for
gravity/figure/thermal/whatever errors in the finished mirror and not used
during turning. Though I suppose if I ran into some weird zonal defect while
polishing I could tweak it out by adjusting an actuator or two ;).

Before I make a decision one way or the other I'm going to part this all
up in Autodesk Inventor 10 and do some FEA then rotate it 90 degrees and see
what happens.
Besides I got a half dozen 16 inch and a couple of 24 inch blanks I'm
going to torture first. Then flatten the one face of the 2 meter disk, flip it
over and inverse parabolize the back side (this is for thermal/stress
equilibrium in the finished mirror) and core it. LOL... Figure it will take me a
year to get up the guts to put a cutter to it.

Jack Hudler

-----Original Message-----
From: CAD_CAM_EDM_DRO@yahoogroups.com [mailto:CAD_CAM_EDM_DRO@yahoogroups.com]
On Behalf Of Harko Schwartz
Sent: Thursday, February 23, 2006 8:03 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] Epoxy Granite

I think that you would be better off in a Vtl type of lathe for stability of
the mirror.


Harko