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Thread: American Tooling & H.I. Materials

  1. #26
    Objection! OptiBoard Gold Supporter shanbaum's Avatar
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    Thumbs up I swear...


    really man, when is the last time you VISITED a real lab???


    Yesterday.


    Since you work for an equipment manufacturer, perhaps you can explain what kind of equipment you will be producing aimed at the small-to-mid-sized lab in the coming years (you know, something designed to produce less work rather than more).


    I could tell you, Pete, but then... you know the rest...

  2. #27
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    Lab Work?

    Well said Robert.

    Mr. Hanlin, it seems to me you have access to labs to test your theories - why haven't you? Essilor's R&D lab has the equipment, so put the theory to the test.

    So I guess, the question is back to you... when was the last time you were in a lab? And I don't mean as a pass thru on the way to the front office.

  3. #28
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    Pete and Robert,
    I have really enjoyed this thread and reading all of the posts. I process a lot of Hi-Index materials and faced the same problems about maintaining the powers as everyone else.

    I looked at all options about what to do with tools and read many opinions. Maybe you will remember the one in Lab Tech or Lenses and Technology that said cut all of your tools to the highest index that you use.

    I really wasn't impressed with going to .10 as I didn't feel that the results would justify all the work in recutting tools.

    What I decided to do was cut my tools in .0625 steps. This way I didn't have to recut previous tools unless worn or abused. I could just fill in as needed. I first started doing this on 1.67 or 1.66 index and gradually added more indexes until every tool I use is cut in .0625 steps.

    This has eliminated the problems on power. It has sure increased my tool inventory but for me the results were worth it.

    Jerry

  4. #29
    RETIRED JRS's Avatar
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    One area that has changed with laps (tooling) in the last couple of years - the introduction of "gripper" pad systems. Depending on the gripper (manuf type) used, the thickness of the gripper pad varies from 0.3688 to 0.4600mm.

    Since most labs compensated (their laps) for the pre-gripper pad thickness, adding the gripper almost makes the laps uncompensated before placing the fining pad(s) on top. This has created some cut curve-to-lap alignment errors - depending on how a lab is configured. And is certainly radius dependent.

    Usually manifests itself by increased uneven stock removal, more aberrations (which may look like power issues), and/or fining marks (swirls) in a lens.
    J. R. Smith


  5. #30
    sub specie aeternitatis Pete Hanlin's Avatar
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    Mr. Hanlin, it seems to me you have access to labs to test your theories - why haven't you? Essilor's R&D lab has the equipment, so put the theory to the test.
    ...btw, thank you for the tone- it will remind me to temper mine in the future.

    Actually, I am in our R&D laboratory on a regular basis. In fact, it is there that the need to address tooling index, increments, etc. has made itself most evident.

    More important than what is seen in the R&D world, however, is what is actually occurring in the "real" world. In the real world, few labs pay very close attention to the surface quality of their tools, the temperature and baume of their polish, and the procedures they use at each and every step of the lensmaking process.

    In the past, in the "real" world, a certain amount of breakage was deemed "acceptable," and- even if the cause of breakage couldn't be defined- it could be tolerated because there is money to be made in the lab business.

    In today's world, the same processes that used to yield a "tolerable" amount of breakage are going to begin to drain the resources of the average laboratory if they are not addressed. That little bit of wax residue that used to go unnoticed on the lens surface is now showing up when the lens is AR coated. That alloy that gets dumped straight from the reclaim tank into the blocker is beginning to spoil more- and more expensive- lenses.

    Discussions like this- discussions that address things like tooling- are important to have. Its even important to have different opinions on the matter. Its important because each lab out there- regardless of the size- represents someone's business. Someone who probably inherited that business from their dad. Someone who would like to stay in the business- but only if it pays the bills.

    As Robert points out, if tools aren't compensated a bit of consistency is sacrificed (and while laying out in the sun this weekend it occurred to me that a -4.00 cyl on a non-compensated tool could get a bit gnarly). As JRS pointed out, even if you do compensate, if the amount of compensation required changes for some reason, you end up with an uncompensated setup anyway. Hopefully, the independent lab owner has exposure to different opinions like this when s/he decides on what tool set to purchase. That way, whatever decision is made, it is an informed decision.

    This has definitely been one of the more entertaining "Ophthalmic Optics" threads! :)
    Pete Hanlin, ABOM
    Vice President Professional Services
    Essilor of America

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

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    Another issue that needs to be considered is that the Dr. is still using 1/8 diopter incriments. When he gets to the part where he says "one or two", or "is A better or is B better" the patient is likely to reply (at least in his mind) "I don't know, you decide"!
    We sometimes try to find "perfect" when there is no such thing!
    :-) Just my two cents worth.

    Shutterbug

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    Wink

    I thought I had replied to this also, but it seems not to have gone through.
    I enjoy the discussion, but it seems to be a mute point given the beginning of the process is less than perfect. I've sat in the examination chair while the Dr. goes from one lens to the next (in 1/8 diopter steps, mind you) and always get to the point where it doesn't make a nickles worth of difference which lens is used. I want to say "You decide!"
    I know the Dr. is always right, but why try for perfection in an imperfect science? That is why we need tolerance from both sides of the business (lab and retail).
    The "scientist" in me cries for "perfect" but it can't ever happen
    from the patient's perspective. The bottom line is still 'how does it look to HIM?'


    :0)

  8. #33
    Objection! OptiBoard Gold Supporter shanbaum's Avatar
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    Shutterbug said:
    I know the Dr. is always right, but why try for perfection in an imperfect science? That is why we need tolerance from both sides of the business (lab and retail).
    The fact that the target may have been established imprecisely to begin with does not decrease the requirement for accuracy in the delivered product - it increases it.

    Were it possible to ascertain RX's with absolute accuracy, any error in the delivered spectacles would be more likely to be undetectable. As things are, because RX's are approximate, errors in the spectacles may push the overall error - the error in the RX plus the error in the product - over the line of detectability.

    That's why.

  9. #34
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    Stick out tongue

    All us lab guys are trying for perfection! :-)

    The fly in the ointment here is that the Dr. is using 1/8 diopter lenses. I've been in the chair trying to decide between "A or B", "1 or 2" and thinking "You're the doctor, YOU decide"! LOL
    The bottom line is how it looks through the patients eye, not how it looks in the lensometer. I find more problems with base curves than I do with powers :0) So the system is still imperfect from the top down. Still ...... we keep trying :0)

    shutterbug

  10. #35
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    Confused

    Hey - I just figured out why my posts were invisible! I'm new here, so just overlook my multiple posts with the same old points. Sorry! I'll figure this thing out eventually :-)

    Shutterbug

  11. #36
    Bad address email on file Susan Henault's Avatar
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    Pete Hanlin said:
    More important than what is seen in the R&D world, however, is what is actually occurring in the "real" world. In the real world, few labs pay very close attention to the surface quality of their tools, the temperature and baume of their polish, and the procedures they use at each and every step of the lensmaking process.
    I am very surprised that more folks like Jerry Thornhill have not chimed into this thread. Perhaps I am niave, or perhaps I just have the priveledge of working with some of the best independently owned laboratories in the business. Most of my laboratory customers pay very close attention to the consistency of their process and are relatively quick to identify problems. In many cases, it is the support they have received from their lens manufacturer partners (such as Zeiss and yes, in years past, Essilor) that have helped them improve and monitor their procedures.

    Due to the overwhelming increase in polycarb sales over the past several years, more than a few independents have upgraded their systems to include 1.60 tooling cut to 0.10D. Combine poly with the "relatively low" percentage of mid & high index orders, and you no longer have a small volume, but a sizeable one. Additionally, labs have unilaterally moved toward forcing ECP's to use only poly or trivex on drill mounts (a discussion of which warrants a thread of its own)-- further compounding the need.

    My hat is off to Jerry. Regardless of the tooling index, a tighter increment of tool curve cut, effectively resolves the issue.

  12. #37
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    I don't know where my reply ended up, so here it is again :0)

    We are using 1.530 tools precision cut to within .003. We don't like to cut our own because we were never sure if the tool was the problem or somthing else. We also recently added gripper pads to our process and noticed that different software use different compensation factors. If the software uses inches and the generator uses mm you may have problems :0). Also the way that rounding is figured differs. Our current program rounds the first curve to the nearest 1/10, then adds (or subtracts) the difference to the second curve before rounding it! This does not seem to be the best idea to me, so we calculate high index curves ourselves. This has helped.
    This might be a factor in many labs.

    Shutterbug

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    Hmmm... I have to side with Pete on the political scene and Robert on the lap issue.

    A little over four years ago, I was the US technical project manager for the creation of Essilor's Avisia lab. Part of my job was to choose the complement of lap tools for the plant, keeping within certain constraints.

    At the time, I took the materials we were processing (CR-39, Ormex, Poly), and having the luxury of using any index in any increment because the laps would have to be custom-cut for the robotic tool picker, I wrote some programs to evaluate the theoretical error of several scenarios (using compensated laps--sorry Pete). Then, having bazillions of dollars to spend, I had several laps cut and ran practical evaluations of the results compared with the theoretcials.

    The practical evaluation proved out the theoreticals, showing higher variance due to process variables. Hey, the real world of lens production is a far cry from R&D, right?!

    In a nutshell, I found what has been proven many times before. You should cut laps to the index of the highest material you surface in the lowest increment you can afford (though you won't gain much by going below 0.0625 D increments because of variable process constraints). I can't divulge what we went with, nor can I share the research paper I wrote on the subject, but I can say it mirrors one I read several years ago from Coburn.

    I was always a fan of John McCain, myself...

  14. #39
    Master OptiBoarder Jeff Trail's Avatar
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    Oh no another one in Pete's corner :) ..even though I would tend to agree, maybe not so much with Pete's original example of the index used and the RX. You almost really need to work in a reverse process here, especially when dealing with the boundries of the RX's and materials. Even though, a few posts up talk was bantered about on how a "refraction" was not exact, we still need to make sure that the greater the power and index the MORE precise we need to be in tooling as well as running process.
    If you considered a nominal power than yes we could be a 12th off and would it tend to have an effect across the plane of the lens, probably not to any great effect, but take an RX other than Petes simple example and lets toss in something along the lines of a 5 cylinder with say a -7 sphere.. than as you go from the optical center and across the merridians of the lens you would have the problem multiplied by a greater number as well as having a direct effect on the acuity achieved through the lens, especilly off axis and oblique astigmitism.
    So I would have to go with setting up the system (if you had to choose an index of refraction) for the greater index and smaller increaments in curve.. lets face it optics are getting MORE complicated than less, so having a system that fit the most demanding to the least would make the most sense.
    But one thing I have not seen mentioned is that the other parts of the process has now become just as important as well when dealing with some of these higher indexes and different materials.. which no matter how much we have tinkered with the tool index the end result in power could be effected (usually to the bad side :)) ... now we should also revamp the blocking, making sure that the correct alloy (or wax) and blocking is done (which could elimate your true curves if you are putting warpage in by heat or not letting the lens anneal)... you would and should have to take into acount the run time and pressure on the cylinder machines, pad grit and thickness as well according to material..oh before the CTP people jump on the wagon :) I have been into a number of the higher production labs where they have run the polish untill it had a dark look and I'm sure the baum rate was non existant.. so even in the CTP process you can still induce heat and waves if you let the polish break down to the point of it being "dark water"
    Tooling to the extreme might be a solution in the long run, but maintaining a full processing system would be just as important if you wanted to take advantage of the more precise tooling... talking about that +1-1 at 90 and being off a smidge.. yea it is not that big of a deal...talking about that -7 with 6 cyl. in a 1.67 index where the problems multiply more quickly...than it's a big deal :)
    I think we tend to forget to look at the "total package" and just the end result when checking in the finished product.. having some person telling them it's off power and not be able to figure out "why" .. very frustrating. I know every lab I have ever went into to try to correct production problems, I always start with the same thing, explaining that the product quiality can be no greater than your worst area in the production line... in our industry it is hard to compensate for a bad step in the process...almost impossible.

    Jeff "grind'em ...if ya know how" Trail :)

  15. #40
    RETIRED JRS's Avatar
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    Your assessment, and evaluation of Pete's opening remarks, are correct Jeff - the total system, not just a single change, is the best aproach. New laps, in a non-existant system of processing, is a waste of money. There are no "magic bullets" available.
    J. R. Smith


  16. #41
    Bad address email on file Susan Henault's Avatar
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    You guys have all made my point -- it is not fair to suggest that labs don't take time to know, analyize and consistently adjust their process to accomodate the changing needs of their respective markets.

    stvnscott: is there ANY research paper you can recommend that underscores the findings you came up with on your project? You mentioned a study done by Coburn -- is that still available?

    Susan (desperately trying to become something other than an "Optiboard Apprentice" :-D)

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