Re: [ATM] Figuring question

[Mike Lockwood <melockwo@uiuc.edu>]

Lance,

lance clarke wrote:
> I'm at a bit of a loss how to proceed.  Figure XP tells me I have a low zone 
> 1.5" from the edge, and the edge is also high compared the the rest of the 
> mirror. I've tried MOT w strokes, coc strokes, long and medium long (and 
> even short just to see what would happen), and TOT short strokes to bring 
> down the outside...always seems to give roughly the same result.  Is there 
> something I'm missing?  Should I blame the lap?
> The mirror is a 12.5" F5.  I can post my test numbers if it helps.

Yes, the test numbers (ROC, mask radii, zonal readings, moving- or 
fixed-source tester) would probably help.  Now for the standard questions:

Also, is your mirror Pyrex?
Are you done polishing?
Or are you still spherizing or are you working on the final figuring?
Have you judged the hardness of your lap?
If not, how long does it take the channels to nearly close during 
normal polishing?
What type of pitch is it?
How thick is the pitch?
What temperature is the room you are working in?
What is the tool substrate made of?

If you are trying to spherize and you have a classic oblate sphere 
shape (and possibly a turned edge) which can look like a low spot 
about where you describe, then here's a link to my page with info on 
how to fix that:

http://bi-staff.beckman.uiuc.edu/~melockwo/mirror_making/oblate/oblate.html

	Mike Lockwood

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