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Thread: Chuck marks

  1. #1

    Chuck marks

    Hello all,
    any pointers?

    I'm getting chuck marks on AR poly lenses. Chuck pressure lowered but now lenses are coming out axis off. The 3m Blue dots aren't helping.

    New Santinelli 9000.

    AR brand doesn't matter.

    Now what am I supposed to do?

  2. #2
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    Use glass.

  3. #3
    OptiBoardaholic
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    Use a 3m blocking pad on back of lenses.
    Joseph Felker
    AllentownOptical.com

  4. #4
    One of the worst people here
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    Quote Originally Posted by jofelk
    Use a 3m blocking pad on back of lenses.
    That helps a lot.

    Also, if it is a larger frame and the edger is taking everything in one step then cut it larger and bring it down.

  5. #5
    Underemployed Genius Jacqui's Avatar
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    We use a blocking pad on the minus side, the sticky helps to hold the lens on axis. Also edge it down in small steps, here we do them in 4 - 5 small cuts.

    Thank you jofelk and For-life. I think by using both his problems should come under control.

  6. #6
    Master OptiBoarder Jedi's Avatar
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    Stop using poly.;)

    /had to be said
    "It's not impossible. I used to bull's-eye womp rats in my T-16 back home."


  7. #7
    Manuf. Lens Surface Treatments
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    Solution ...............................

    Quote Originally Posted by mrba
    Hello all,
    any pointers?

    New Santinelli 9000.

    AR brand doesn't matter.

    Now what am I supposed to do?
    Send it back for credit and do lenses by hand:cheers:

  8. #8
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    Could it be a problem with the lenses getting hot? That is the only time i had problems with a Briot 6000 when using hard buttons, the buttons were marking the lens through the pad, problem was solved by changing the wheel.
    Maybe necessaryto change the wheel or use rubber type buttons.
    Rick

  9. #9
    Thank you for all this. I think I have found a level of chuck pressure that solves both problems. We shall see at final inspection in about an hour. The double blocking pad thing was tre good!

  10. #10
    Optical Clairvoyant OptiBoard Bronze Supporter Andrew Weiss's Avatar
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    We have a Horizon II, which also has adjustable chucking pressure. For poly with A/R, we use chucking pads on both sides and set the pressure at 10 psi. This seems to be sufficient.

  11. #11
    Master OptiBoarder ziggy's Avatar
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    chuck marks

    mrba, when we would get them in cr-39 we would put them in the water bath(or uv/sc) of the tint tank the heat would draw out the "dent" give it a shot next time.:cheers:
    Paul:cheers:

  12. #12
    Did that to a spectralite last night... In the hot air warmer. It was cool.

  13. #13
    sub specie aeternitatis Pete Hanlin's Avatar
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    By chuck marks, are you getting an indentation or an area of crazing that looks like fog?

    If the mark looks "foggy," the problems are either related to chuck pressure (as you've suspected) or a mismatched chuck and block. If the problem is pressure, you should see just a "dot" of fog in the center of the lens (maybe 5-6mm around). If the problem is a mismatched chuck and block, the mark will look like a target (dot surrounded by a ring in the shape of the block).

    The solution for mismatched block and chuck is to use the same size for both. With all the small frames, its become popular practice to put in the smaller chuck (to avoid grinding into it). However, if you are still using the larger block, this creates an area of flexure.

    Anyway, I hope the pressure adjustment solves the problem. If it doesn't, and you would like, feel free to send some lenses in for evaluation and maybe there are some other fixes that could be suggested.

    Just a note of warning- putting an AR coated lens in any frame warmer can cause crazing if the temperature gets anywhere above 150F or so, especially on a material that expands a lot under heat (like poly or high index).
    Pete Hanlin, ABOM
    Vice President Professional Services
    Essilor of America

    http://linkedin.com/in/pete-hanlin-72a3a74

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