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Thread: Build a better tape machine, and they will come...

  1. #1
    sub specie aeternitatis Pete Hanlin's Avatar
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    Build a better tape machine, and they will come...

    Hi everyone... One of the problems we see with surfacing operations concerns the application of tape on raised segment lenses. Basically, a bubble often forms on the lens surface, and- if it isn't pressed out before blocking- there is a spot on the lens that isn't well supported (which leads to an aberration right at the optical center).

    Anyway, I'm driving home last night and thought "why apply the tape from the top?" Imagine a lens blocker with a block of pliable, rubber-like material. The tape could be placed on top of the block (with the sticky side up) and the lens could be pressed front down onto the material. Since the front is receiving pressure and is being forced into a pliable surface, the tape should be pressed into conformance on the entire surface.

    I find with most of my "new" ideas, there is usually already a piece of equipment out there already in existence. Has anyone seen a tape applicator similar to what I've described (or can you already think of a reason why this wouldn't work)?

    Thanks!
    Pete Hanlin, ABOM
    Vice President Professional Services
    Essilor of America

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

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    Bad address email on file John R's Avatar
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    We have the same problem with execs in glass. The way we cope is to press the tape down by hand afterwards.
    Pete is this not why people started using the one step wax..Which does not require tape but still needs tape to keep the lenses clean..

    Biggest problem i can see is aligning axis and heights as you're only going to get one shot at getting it right.
    Dream on Pete...

  3. #3
    sub specie aeternitatis Pete Hanlin's Avatar
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    Biggest problem i can see is aligning axis and heights as you're only going to get one shot at getting it right.

    Actually, the wax (aka "Freebond") system encounters the same problem (if tape is used before blocking- which is recommended to avoid contamination of the surface before application of AR stacks).

    Are you referring to blocking in the same process as taping? I don't know if your process is different, but here we usually have a "taping" machine that has a platform and a ring. The lens is placed front side up on the platform, the tape is pulled across the opening, and the clamp is used to secure the edges of the tape. Then the platform raises the lens (which presses it into to the tape), and an Exacto knife (or a hot knife) is used to trim the tape. The problem I see with this system is that the tape is stretched across the surface. My way would put pressure on the tape without stretching it...

    PS- I am guilty as charged (about being a dreamer)... thank the good lord you don't have to hear some of my other "brilliant" ideas!
    :D
    Pete Hanlin, ABOM
    Vice President Professional Services
    Essilor of America

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    Bad address email on file John R's Avatar
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    Pete Hanlin said:
    Are you referring to blocking in the same process as taping?

    My way would put pressure on the tape without stretching it...
    No we use just the same system for taping lenses.
    I thought you ment blocking and tapeing at the same time...Having re-read the post i see you didn't. :hammer: I must be getting tired as i'm missing the points...
    Nice idea though.

  5. #5
    Master OptiBoarder Joann Raytar's Avatar
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    Coburn's Matrix AR laminating system (or whatever you would call it) had an assembly similar to what you are describing. You put the wafer and glue lens "sandwich" down on a backlit acrylic platform and a mini airbag would inflate and compress everything together. To create a taper using the same type of assembly would probably cost a pretty penny.

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    Pete:

    I used to have (back when flush-fitting scleral lenses were in vogue to cure the uncurable) a press similar to a drill press that had a head of semi-soft silicone. We would take a model of the patient' eye, heat a thin (1 mm) acrylic wafer an place it over the model. Then press it flush over the eye model. Perhaps something similare could be made to accomplish you purpose. I know that I have occasionally wished for same when trying to get all the bubbles out of fresnel pasters.

    Chip

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    Master OptiBoarder Jeff Trail's Avatar
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    Pete,

    You are forgetting the biggest problem, cost effective process :-) Now it costs around .02 or so to tape a lens... how much do you figure getting your little rubber pre-molded filler would cost per lens? It would have to come in a variety of sizes for all the blocks (disposable, 40 mm, 55 mm etc. etc.) the trickiest part on top of that, I would think more so than axis and centering would be having it set properly into the block (no prism wanted here :-) You also would have to come up with a complete new blocking system.. either a saddle the different lens can set into flush and apply some type of pad press to the back of the block.. or vice versa ... and HOPE you never have to re-block a finished lens...yikes talk about cracking :-)
    BTW you do know that they make a "spray" version of tape saver didn't you? :-) ..comes in a can looks like a spray can and you apply it to the surface like paint...I never liked it myself, kinda messy and more expensive version of tape saver..
    This is one of those things where does the cost warrant the benefit ... to get rid of that "bubble" you need a $20,000 system... when the times it does cause a problem usually it's only in the area of extremely high adds...
    I always thought having a flexible tool was a neat idea..sort of like those "stress" balls you squeeze, "one tool" fits all RX's, no more 2,000 laps having to be maintained and kept in order.....and have talked about it for years.. and here someone came a long and did it :-)

    Jeff "someone give me the winning lottery numbers" Trail

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    Bad address email on file John R's Avatar
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    Jeff, You're dropping into the same trap as me..:hammer: Pete's not talking about blocking the lenses only a diffrent way of applying the tape.. Rather than the lens hitting the tape. THe tape hitting the lens.

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    Master OptiBoarder Jeff Trail's Avatar
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    Oh ho...so we skip making it part of the "blocking" and just worry about the taping...but here is where you would still run into problems...you are wanting a "flat" thing adhere to a multitude of curves (base and seg) and "not" stretch ...by using the base soft mold to be used as a sort of pad press .. a couple of problems, rubber tends to loose its elasticity to quickly, and you would still have the same problem but just doing it backwards..that seg is just to sharp of a short angle.. FT45 are the worst for the air bubble attacks, but more or less just running a metal PD stick along the taped seg line usually solves it... maybe we should get a bunch of metal PD sticks and just print our name on it and call it the "bubble removing seg adhering tool:" :-) only work if you put about a $45 price tag on it..
    I tinkered with a pupilometer for awhile that had the PD's as well as a fitting target with a grid system so you could take the PD, and take all the fittings off of it while the patient was wearing the frame they wanted the lens put into.. no one seemed interested in my idea though :-)

    Jeff "just use that spray saver **** if you have a phobia about bubbles" Trail

  10. #10
    RETIRED JRS's Avatar
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    Some years back, either OWC or Coburn, developed a blocking system (for surfacing) that used a form of thick adhesive - double sided tape, if you will. I was at the NOSTRA (Navy) lab when they were experimenting with it. It was an interesting design. And used a device similar to a pad press to apply the lens to the block. From a labor standpoint is was slow. From a cost standpoint (Jeff's comment) it was expensive. There were also a considerable number of 'de-blocking' issues that needed to be overcome. Needless to say - it ain't around anymore.

    There are some fairly sophisticated taping machines on the market now. Some are almost completely automatic and will do 2 lenses at the same time. The fundamental issue Pete mentioned - air pockets above the seg, are still a point of contention. The labs I know running these dual machines, still press the seg lines by hand. Taping speed, from a throughput standpoint, is still faster than the single head type we are most familar with.
    J. R. Smith


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    registeredoptician Refractingoptician.com's Avatar
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    Last edited by Refractingoptician.com; 02-15-2007 at 09:32 PM.

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    Bad address email on file John R's Avatar
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    Re: taping in air bubbles

    Gary said:
    If the problem is air bubbles then the correct solution is to eliminate the air. This would be done by a vacuum. Therefore , there would be no need for a flexible anything. Someone would need to study up on Fibreglass vacuum-bag molding processes and techniques and the answer would likely be very simple. And inexpensive.
    This is basicly how a tape machine works now...
    The problem is how to get any material other than a liquid to comform to such small, but important changes in curves (Read Seg line) Tape is very flexible now, even if it was thinner it still could not cope with the seg line.....

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    registeredoptician Refractingoptician.com's Avatar
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    Last edited by Refractingoptician.com; 02-15-2007 at 09:33 PM.

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    Master OptiBoarder Jeff Trail's Avatar
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    Gary said:

    I am saying this, but I don't do surfacing, so I haven't had the benefit of seeing how a present day tape saver machine works. Does it already apply a vacuum between the lens and tape? Or does it just press the lens up into the tape? Is the tape heated ?

    Gary,

    You drop the lens inside a small cylinder (air driven) the tape is pulled over the cylinder and when you shut the ring around the top (to make sure it seals) the cylinder pushes the lens up into the tape...
    The key thing to remember is speed is the name of the game for wholesalers and low cost per unit.. anything slower more involved and more expensive is not going to work. Maybe in a slower retail situation of labs they would use something fancy and slow :-)
    Wholesalers want it fast and the cheapest way possible, right now it takes about 3 or 4 seconds to tape a lens ...and the key to wholesale production is speed and a flow.. you mess up the flow just to make sure that a bubble is removed, which by the way it becomes habit in a lab when cutting the tape removing the lens you automatically run your finger along the seg line.. I don't think you'll find a cheaper way to do it :-)

    Jeff "sometimes the fly swatter is better than the electronic computer chipped pest removal system" Trail :-)

  15. #15
    sub specie aeternitatis Pete Hanlin's Avatar
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    Jeff
    Actually, reading your response is making the picture of this machine clearer and clearer in my mind (an amazing feat given the clutter and cobwebs up there, you should be proud).

    Okay, here is my latest envisionment... An air filled bladder sits at the bottom of the tube. The bladder has a convex surface, so the center of the bladder is the first thing that will hit the lens. The tape could come in pre-cut circles (like the little circles used for edging AR coated lenses- only larger). You throw a circle on the bladder (sticky side up) and push the lens front down onto the bladder. The bladder (which could be adjusted since it is air filled) gives way and presses evenly from the center out (eliminating air bubbles on top of segs), and because the tape is already cut, there's no need for a knife of any sort.

    Even better, there could be a special circular tape "dot" for use with higher base curves (with radial cuts around the periphery of the circle, to prevent wrinkles and bubbles at the edges of the lens).

    PS- If you've ever seen a "Hexapod" work, it should be obvious that an automated machine to do the taping using these circles should be a snap to create...
    Pete Hanlin, ABOM
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    Essilor of America

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    Master OptiBoarder Jeff Trail's Avatar
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    Pete Hanlin said:
    Okay, here is my latest envisionment... An air filled bladder sits at the bottom of the tube. The bladder has a convex surface, so the center of the bladder is the first thing that will hit the lens. The tape could come in pre-cut circles (like the little circles used for edging AR coated lenses- only larger). You throw a circle on the bladder (sticky side up) and push the lens front down onto the bladder. The bladder (which could be adjusted since it is air filled) gives way and presses evenly from the center out (eliminating air bubbles on top of segs), and because the tape is already cut, there's no need for a knife of any sort.
    Pete,

    I'll play Devil's advocate here, maybe we can refine it a little further. first Your idea of an air bladder would seem like a simple solution, BUT (don't you love it when someone says that?) :-) If the bladder was in the bottom of the cylinder you would have to figure out some process for clamping the lens down in the lid and move the bladder upward..to complicated since we have a large choice of lens diameters we deal with in uncut blanks... so lets reverse it.. but than you have the same problem again, how to get the tape to stick to the blabber till you move it down to the lens surce, you don't want sticky on both sides you end up with a mess as the glue would build up and it slows you down.. :-) Good try ..
    BUT (there I go again) I do like the idea of a cone shape as well as the trick about higher base curves, especially along the lines of E-lines and ARRRG lenticulars and 10 base and higher in full field.
    Any one here with lab experience can attest to what a pain it is taping up an 18 base lenticular without having creases in the tape and bubbles all over the place.
    Boy this has been your week for starting fire storms Pete, who would have thought the simple posts you made would bring all this fury, if I were those ones thinking you were "blowing" Essilor's horn, I would more lean towards you being bribed by Hoya and Younger for giving Trivex all the publicity :-) ..can't win for losing :-)

    Jeff Trail

    P.S.
    any new developments on the "thing" we talked about? :-)

  17. #17
    sub specie aeternitatis Pete Hanlin's Avatar
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    I'm off to get some actual work accomplished, but the bladder could stay stationary. An arm would grab the circle, swing over and apply just a little pressure on the center (to adhere it to the center of the lens). A suction cup would grab the back of the lens in the center (thus making the size of the blank a non-issue) and would swing the lens above the bladder and then press down.

    The pressure within the bladder and the pressure of the arm positioning the lens could be controlled depending upon the lens type, design, material, etc. In this age of automation, this would create consistency in the taping process (consistency being the golden fleece of production and all).

    What'ya think JRS and Jeff??? Can I start getting ready to retire yet?
    Pete Hanlin, ABOM
    Vice President Professional Services
    Essilor of America

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    Bad address email on file John R's Avatar
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    Wink

    I still dont think it would press the tape over the seg line Pete...
    For it to form a air free zone it would have to be a very good fit over the seg line other wise it will just take the easy way out and not press the tape down.

  19. #19
    Master OptiBoarder Jeff Trail's Avatar
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    John,

    Can tell you one little trick I do with those high adds (do a lot of 4.50's and higher) and FT45's is I'll put a smear of wax with my finger to fill in the gap and to make sure it does not chip the seg lip :-) before popping on the tape.. even leave it on if it's still sticking right up through the leap blocking and edging so the lens won't sit angled when popped into the edger..I do have less problems since my patternless edgers use pressure sensitive electric chucks instead of air chucks but still I had some chips once in a while on the seg line.. the wax works great, or I'll double over a leap pad to fill in the gap.
    I think Pete is closer to something, but still to make it a money saver instead of a money pit compared to the systems we use now I think ya got a long way to go brother :-)

    Jeff

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    opti-tipster harry a saake's Avatar
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    Lightbulb

    Hey Jeff, i think i got the answer, you just go out and buy a large can of that silly putty, put it over the seg line and when you clamp down with the tape the silly putty will fill in any voids.:cheers:

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    Spray.......

    As we speak, there is more than one company developing a fast, cost effective solution to this problem (for larger volume operations) It works like this basicly like a backside coater:
    layer of FLUID (or spray) that is some what thick is sprayed onto front surface of the lens, the lens is then "cured" by air, UV, or heat very quickly. The lens is blocked, processed, de-blocked, and when rinsed under water the "coating" (water soluable) melts away. (so they say.... beleive when I see)

    Spray or liquid = no air bubble

    So this could be a VERY cheap "back side coater", since contaminates will not be an issue.

    My only question is what happens when the "stuff" keeps comming off while polishing (increasingly contaminating the polish) on the new "cut to polish systems that are comming out now.

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    registeredoptician Refractingoptician.com's Avatar
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  23. #23
    RETIRED JRS's Avatar
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    Old news Myodisk.

    That is the way it was done prior to Surface Saver Tape. You either bought it (the coating) in a spray can, painted it on with a paint brush, or had a conveyor system that sprayed the lenses as they went by. Air dryed, then blocked. Coburn made a variation of it, as did ArmourLite.

    In the early 60's, we hand cut 3 inch rolls of tape. Applied the tape to the lens, then put the coating on by one of the above methods. If I'd have put the 2 together and put it on a roll, I could have retired!

    We had a few problems when computers first arrived, as the the "thermal" paper reacted reacted badly to the solvents. We used to use thermal paper in some of the old lens calc systems.

    Surface Saver Tape works fine. Only takes a second for the operator to minimize the air pocket over the seg. Not required that the entire pocket be removed.
    J. R. Smith


  24. #24
    Forever Liz's Dad Steve Machol's Avatar
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    I was thinking the same thing JR. We uses to use the Armorlite spray - I think it was called TB-Lite.

    One thing to keep in mind is that if the air pocket it too large this can result in unwanted aberration at or near the optical center. You can readily see the effects of misapplied tape when viewing the lens through an arc lamp.


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    Bad address email on file John R's Avatar
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    By Myodisc
    Spray or liquid = no air bubble
    Yep but spraying has its own problems in getting a even coat and not getting runs while waiting for curing.

    Gary....Time...
    The present taping machines do use a vacum of sorts to drive the lens onto the tape. The air is sucked out causing the piston with the lens on to rise into the tape. Its just there is not enough presure to remove all the air from such small areas.

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