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RE: RE: Time Will Tell

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Posted by Rick Crockett on April 5, 2000 18:05:00 UTC

The Big mirrors are Ceramitized after polishing. Ceramitizing locks the glass into a crystal structure so it is more stable but also more delicate. By grinding into a Crystal structure, new stresses may be introduced. That would be a bad thing but may not happen at all. I have repeatedly tried to get answers from places such as Newport, as to what "precision" means vs "fine" anneal. The latter is quite acceptable for any application I know of so is "precision" just hype to get that extra dollar from the yuk yuks with bucks? If I were to pay extra for a feature in glass, I certainly would want to be able to quantify and qualify. How does one tell the difference between "fine" anneal and "precision". It could mean Newport just slops off "course" annealed for "fine" and now needs to call "fine", "precision".

My recommendation would be to check for strain after polishing. If necessary, the blank could be re-annealed and then finished as a worst case.

Good Luck,
-Rick

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