Too often when edging stock poly or 1.67 alize and avance the a/r coating crazes. Any suggestions? I end up surfacing them with a minimum center of 1.7 to avoid this problem.
Too often when edging stock poly or 1.67 alize and avance the a/r coating crazes. Any suggestions? I end up surfacing them with a minimum center of 1.7 to avoid this problem.
Last edited by witzoptical; 12-21-2009 at 06:27 PM.
What is your edging process? I find the following very important:
- Low pressure settings
- Putting an edging pad on each size
- Matching up the diameter of the chuck to the diameter of the other pressure point
- Slowly twisting off the chuck upon completion versus ripping it off
I have a Santenelli 7070. It is set on low pressure, but the lens seems to bend alot when chucking. What do you mean by the diameter of the chuck? Base curve of chuck?
It sounds like you need to let the lens go against the wheel lighter. It should not bend. Maybe take it down by hand a little.Originally Posted by witzoptical
What I means by chuck diameter, and this is going to be non-technical because I do not know the technical terms, but you have the clamps around the lens. On one side, you have the chuck. That side is the side that sticks to the lens. On the other side, it is a pressure point that holds the lens in. Ok, now if the chuck has a different diameter than the other side, the lens will press against the chuck and bend. I know for us, I had to use the smaller chuck sizes for all of my edging. The bigger ones were causing this problem
Call them and replace the chucks with their flexible pliable cup. It covers more surface area and has a solid hub therefore the lens is supported better and flexes less. AND listen to the previous suggestions
Money carefully refunded
On the 7070 I used to operate I would always use the biggest possible chuck, then using low pressure set my size about 3mm larger than my finished size and rough the lens down and stop it. Restart the lens again and let the LMU remeasure for a more precise bevel/groove placement on narrow "B" frames. As far as the crazing on A/R always use low pressure and don't flex that lens when you deblock. Ease those blocks off using a little warm water if you have to. Flexing those A/R lenses is the Kiss of Death.
Chris Beard
The State of Jefferson !
I'm a Medford man – Medford, Oregon. Up in Medford, we take our time making up our minds."
Stop using Avance stk lenses. I have.
Crazing completely gone. No muss.
No fuss.
It's not you or your edger. It's the crizal coating that is the issue.
FWIW
Barry
the main thing that got me to and continued having me use Crizal is the crazing was about 10% of other big name and little name AR's on the market.
I've institued *all* the admonisions and cautions that have been cited with respect to crazing.
Once I moved from Crizal Stk lenses, I've NEVER had any more crazing issues, short or long term.
Barry
Here's the Essilor paper on the subject, again.
It seems the Tharcle paper is a PP. Email me if you want a copy at besantini@optonline.net
Barry
Last edited by Barry Santini; 03-19-2016 at 06:20 AM.
The Tharcle paper is a PP? That's a new one.
Chris Beard
The State of Jefferson !
I'm a Medford man – Medford, Oregon. Up in Medford, we take our time making up our minds."
Yes, it's a Power Point. Please email me for a copy.
Barry
besantini@optonline.net
Put "Tharcle" in the subject line
Last edited by Barry Santini; 03-19-2016 at 06:20 AM.
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