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Thread: Causes of Repeat Failures of Crizal on Poly

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    Causes of Repeat Failures of Crizal on Poly

    I'm having a fairly consistent problem with Crizal Alize on Poly. This has happened in the past and I'm looking for possible causes. I continue to get defects in the coating during edging/beveling/mounting. No matter how gingerly I handle the product, the final inspection may yield either small linear cracks or what appears like a hazy spot with a 'fingerprint-like' pattern. Usually the defects are only visible when light strikes the lens at a certain direction. The defects are nearly invisible when inspected in most orientations, but get the light just right and they become clearly evident.

    I looked at edging and there have been some that have come through with the defects even before hand beveling. Others seem to make it through, but may fail during de-blocking or possible excessively tight mounting. I'm even wondering if my wheels need dressing. I have a low volume practice and I'm running an Essilor Kappa that's really in very good shape.

    The problem seems far more common in single vision - no difference whether it's stock or coated surfaced product. Certainly lens thickness is an issue. Poly is definitely softer and maybe Crizal is just plain too hard for reliability on poly. I'm just searching for answers and wondering if Crizal on poly just isn't worth the effort.

    Is this a particular problem with Crizal? Have others experienced these failures? Thanks for your input
    Last edited by icare; 05-11-2017 at 07:17 PM.

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    Looks like this topic has been approached before. I've learned a lot by reviewing previous threads. I'm still wondering if there are any other coatings that might be easier to handle than Crizal. Sorry if this thread seems silly. I've been edging on my own for 20 years and somehow only periodically run into this problem. I should keep the circumference down (always liked a tight/perfect eye wire closure - hate a wobbly or loose lens) and should definitely sharpen these wheels!

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    Master OptiBoarder OptiBoard Silver Supporter lensmanmd's Avatar
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    You hit part of the solution by dressing your wheel. There are two things that stand out.
    First is the condition of the roughing wheel. Something tells me that it may be worn and needs to be replaced. You did not mention if you were having slippage. No slippage with a dull wheel means that your chuck pressure is too high. I'm guessing that these stress fractures are at the GC.
    Second, going back to the chuck pressure. You will need to adjust it. Are you base matching the blocks? Are you using the largest chuck possible? Are you using any protective discs on the back side? When de-blocking the lenses, are you applying any downward pressure, or just twisting the lenses without vertical pressure? Yes, many questions.
    And no, its not just Crizal. Standard/premium stock AR of all brands, even surfaced lenses with AR will craze with excess chuck pressure and/or blocks that don't support the center of the lens. Much to think about.

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    Master OptiBoarder LENNY's Avatar
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    We had this happened on 2 Kappa CTDs! We tried everything and only one thing helped!
    We changed the edger to Mr Orange.
    I also heard that changing to 1.60 with crizal helps reduce the issue by 75-80%, but in our case this is more costly then a new edger!

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    Thanks, lensmanmd and LENNY -
    I dressed the wheels and a fellow edger support expert also suggested keeping the rubber chucks in water - to keep them supple. I'm actually looking at the Kappa Blocker, too, because sometimes it seems to block more firmly and that's another no-no.

    I'm really not a fan of Poly, but the orders keep rolling in :/ Thanks again for your input!

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