ATM 6:1 Flexture for Ribbed Blanks

[ric rokosz <ab866@freenet.durham.org>]

One of the best articles for determining the flexture characteristics of 
ribbed light wieght blanks can be found in SPIE vol 1236 Advanced 
Technology Telescopes IV 1990  pp735 -743.
This article was written by Parks,Cannon and Wortley of Hextek Corp. and 
details their rational for the parameters of their fused blown blanks.

They detail two aspects of lightwieght blanks construction : one is the 
degree of polishing pressure on the faceplate that determines the 
faceplate thickness and secondly the deflection patterns of a semi hollow 
body (blank with spaces in the cavity) versus a solid blank.For the 
latter they determined a 24 inch blank (solid) could be 2.25 inches 
thick,and achieve acceptable images.

Another article of more academic interest is "Lightweight mirror 
srtucture best core shapes:a reversal of historic belief." in Applied 
Optics vol 27 #2,January 1988.BY Sheng.
This article details the rethinking on hexagonal shaped ribbs -triangular 
are better for large blanks as the spun cast ones.

Ric
Toronto