Re: ATM How much Flexure to Allow in Mirrors? Advice Sought

["Jon Bertrand" <jonb@cirris.com>]

     Richard,
     
     Maybe the guy from Japan who was featured in S&T several months ago 
     (the mechanical engineer who is a finite element analysis wizard) 
     could be of assistance.  S&T listed an EMail address for him in the 
     his last article.
     
     I don't have the issue with me but I'll look up his address tonight 
     because I've been wanting to ask him some questions....
     
     
     Jon Bertrand
     jonb@cirris.com


______________________________ Reply Separator _________________________________
Subject: ATM How much Flexure to Allow in Mirrors?  Advice Sought.
Author:  Richard Schwartz <richas@chelsea.ios.com> at Address-InternetPO
Date:    8/7/96 1:11 PM


-- [ From: Richard Schwartz * EMC.Ver #2.5.02 ] --
     
I have been calculating mirror flexures in a crude way to get a rough order 
of magnitude of the number and depth of ribs required to support the 
structure.
     
My present design goal is a maximum flexure of one micro-inch.  Is this a 
reasonable value?
     
The number of ribs required depends on the support the mirror receives 
during polishing.  If the mirror is uniformly supported during polishing by 
a special (easily constructed) jig with compliant supports, then the mirror 
structure can be much lighter. 
     
I am designing around a polishing pressure of 0.1 psi.  Is this a reasonable 
value?  
     
Polishing pressure distorts the mirror shape much more than gravity (for 
small mirrors like mine).