What is the maximum blank size for an autograph II polar 167? I have a pt that needs a blank around 76mm to make cutout and my main lab swears that it only comes to a 74. Secondary lab won't do an autograph and the last one, owned by essilor blarg, can't give me any info.
I thought part of the whole point of using a spherical blank was that you could use whatever size you wanted and then even play around with where the pd and seg started, or am I just remembering things?
That is correct, except that the manufacturer needs to know the parameters of said blank in order to make accurate calculations in the design of the lens. That is why Essilor blarg (:) sorry, that made me smile) touts their state of the last decade free form products for using lenses made by Essilor, touting that their blanks are more superior than competitor blanks (pissing match anyone?). So, you still end up with product availability limitations because the manufacturer needs to know what blank you're using in order to make the calculations for the lens.Originally Posted by gunner05
I don't understand why essilor can't help you though, since they now own part of shamir.
First, I can get a 75mm blank from three different vendors.
Second, yes, on the Autograph II family, within certain limitations, the actual "progressive" is ground decentered, both horizontally and vertically (when needed) to give a lens a much larger effective blank size.
Third, your lab is wrong.
Now it will depend on frame dimensions, Rx, PD, Seg ht, and exactly which design you're using. If you want to either PM the info or post it here, I can run it through our system and see what it says.
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
Gracias, that's what I thought, but as my lab rat days are over and I no longer run jobs, I tend to try to listen to what my rep says.
Essilor can't help for the same reason that an Essilor rep can't explain the design of a Kodak Unique or Shamir Autograph II. While there is ownership, there is no communication or training. And for the record, other than their ownership of Shamir, Essilor does not produce Free Form lenses (except, technically, the Ideal, which no one uses). Their Enhanced and 360 lenses are standard molded progressive digitally optomized. A far cry from Free Form.
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
I just ordered an Auto II in an amber tinted polaroid. I also assumed that if a single vision blank existed it could be turned into an Auto II. Nope, according to my lab. Only certain colors, like Brown C (not even Brown A !!) are listed, and if not listed, can't be done. This just has to be wrong. I get different answers from different sources.
Your lab is both wrong and lazy. We did an Auto II in the KBCo Sky Blue a couple of weeks ago and it worked fine. I had to add the lens to our LMS as being possible to do, but that took me about 5 seconds. The material simply needs to be assigned Shamir's material code for, in our case, CR-39 Polarized. Color is irrelivant.
If the lens comes in Single Vision, it can be done in an Autograph II. Except for materials that Shamir has not worked out the software for. So far, this is only 1.70 and 1.71 (but they do have 1.74). EVERYTHING else is fair game. All available polarized colors are certainly possible.
At the very worst, your lab could have simply told the prescriptor that the lens was a Grey-C CR-39 and it would have run fine.
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
Thanks, WFruit.
I meant ELOA, not an essilor product rep., making perhaps to great an assumption that ELOA is making shamir lenses.
A far cry, indeed.
I would say following protocol more than being lazy. Correct me where I'm wrong, because my understanding has been that the manufacturers don't want their lenses produced on non-approved materials because they don't have the software written for it. Perhaps I am naive to think that CR-39 from one source is different than CR-39 from another source, just as gasoline from one gas station is different from gas at another. Sure, you technically can run a product on a different material, just like you can apply AR coat to a fork, but you ought not to. I want free-form Drivewear, but it isn't going to happen anytime soon.
No, they're lazy. Or don't care. Per our Shamir sales rep, Shamir technical rep, and the Shamir VP of sales for our region, there are NO non-approved materials, with the exceptions of 1.70 and 1.71. I couldn't force those anyway because there is no software for the lens calculations specific to those materials. I could probably tweek 1.74 to make it work, but I wouldn't and I don't think it would be worth it (rumor is that Shamir's working on those though). However, as far as the specific question, different color polarized lenses, I specifically asked, and was told I could do, any color available. In the LMS/Shamir prescriptor, it simply states "CR-39 Polarized" (it states all the other polarized materials as well, I'm just using CR-39 as my example). No color is specifed. Like I said, it's a 5 second modification to attach the material code from Shamir to that particular lens, and it's good to go.
Now, all of this is specific ONLY to Shamir. There are other Free Form companies, Seiko for example, that specify that you do have to use their blanks for their Free Form Designs. While Shamir does make SV lenses, they are doing so more to insure that all of their designs can be made in a dispenser's material of choice.
And we offer ALL of the Shamir Free Form designs (except the Office) in Drivewear, with Shamir's blessing. And we have been for two years now.
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
Fabulous, I'll definitely be checking that out with some labs, then. Thanks for the info!
You're welcome. If none of them will do it, let me know and I will.
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
Just keep in mind that this may not be the case for all free-form lens suppliers. If the free-form lens supplier has a process engineering program in place to ensure consistent quality and accuracy, the various free-form cutting and polishing parameters must be individually tweaked and tested for each new lens material, even if the material has a common refractive index. Although it is a relatively simple matter to plug in a new refractive index into lens design software, the kinematics of the free-form generating and polishing processes will differ depending upon the physical properties of each lens material.If the lens comes in Single Vision, it can be done in an Autograph II.
Additionally, if the free-form lens supplier uses a more rigorous optimization algorithm, there may be a limit on the range of base curves that can be used for a given prescription, since any pre-defined optimization weights will be sensitive to the choice of front curve. Factors such as the diameter and thickness of the lens blank must also be considered, since these influence the calculation of the lens design over an "extended" region, the range of prescriptions that will cut out, and so on.
Consequently, the more precise a free-form lens design or manufacturing process is, the more likely you are to see limits on the lens blanks that can be utilized or the prescription ranges that can be generated.
Best regards,
Darryl
Darryl J. Meister, ABOM
I did specify that it was specific only to Shamir. And they do have VERY specific ranges for what powers can go onto what base curves. This is one of the reasons that they have released there own lines of single vision blanks, to insure that the required base curves are available.
Our LMS know what design we are using and what manufacturer blank we are using for the lens, and compensates accordingly. For example, not all 1.67 lenses actually have an index of 1.67. There are 1.666, 1.669, 1.671, etc. The front curve of a 6 base is almost never 6. It can literally be anything starting with 6, i.e. 6.12, 6.27, 6.53, etc. All of this is taken into account, along with blank thickness, diameter, what backside hard coat we use, how many lenses have been generated so far on the machine, and a host of other factors. The biggest impact we've found is actualy polishing time, which not only varies by material, but also by vendor.
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
Yes, which is why I specified that this is not the case for everyone else. ;) Although my post was directed more at others, I think it is important to emphasize this distinction, since many eyecare professionals assume that any product with the word "free-form" in the product description works or performs basically alike, which is very far from the truth.I did specify that it was specific only to Shamir.
My understanding of their product is just the opposite. In fact, it's more in line with what you stated earlier, which your latest post seems at odds with:And they do have VERY specific ranges for what powers can go onto what base curves. This is one of the reasons that they have released there own lines of single vision blanks, to insure that the required base curves are available
Best regards,If the lens comes in Single Vision, it can be done in an Autograph II.
Darryl
Darryl J. Meister, ABOM
In reality, no 1.67 lenses actually have a refractive index of 1.67 according to US standards. There are essentially two "1.67" materials, MR-7 and MR-10: MR-7 has a refractive index of 1.658 in the helium d-line system and MR-10 has a refractive index of 1.661 in the helium d-line system.For example, not all 1.67 lenses actually have an index of 1.67. There are 1.666, 1.669, 1.671, etc
The use of "1.67" to describe these materials was started by certain Japanese lens suppliers who began marketing their products in the US using Japan's mercury e-line system in order to make their lenses seem thinner than other vendors' using the same materials. The mercury e-line refractive index will always be higher than the helium d-line index.
But, even though these two lens materials share a very similar refractive index, they have different physical properties, including glass transition temperatures, surface hardnesses, tensile strengths, and so on. So the ideal free-form machine code settings for these two materials will differ slightly.
Best regards,
Darryl
Darryl J. Meister, ABOM
I've been making that arguement for years now....and even had some success. Unfortunately I think we're still going to be clarifying "Free Form" for many years to come.
Free Form = A lens with a back surface progressive design. The lens may be spherical (in the case of Shamir and Seiko) or additionally front size optomized (in the case of Hoya and Zeiss). A "true" Free From lens will also have compensations for POW.
Digitally Surfaced = A front side molded progressive generated on a digital generator, usually with the curves optomized by software compensation (Essilor).
Digitally Molded = A front side molded progressive which has the design based on a digitally designed and compensated mold.
Those are my definitions and I'm sticking to them until someone convinces me otherwise.
Well, yes and no. Once upon a time, you would see lenses only in even or odd base curves (2,4,6,8 or 1,3,5,7). Because of Free Form using single vision blanks, and because of the base curve requirements, almost all single vision lens materials are now available in ALL base curves (1,2,3,4,5,6,7,8,9,10,11,12) from almost all single vision lens vendors.My understanding of their product is just the opposite.
So, I will admit that it would be more accurate to say "If I can get the base curve needed in single vision, it can be done on an Autograph II." I would also like to add that I've never been able to NOT get a needed base curve. And the Shamir ranges are fairly narrow, about .50 diopter leeway for the true curve of the lens.
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
And I did actually know all that ;). I can confirm that Shamir does differenciate in their software. Partially it goes by vendor, so for example, it knows that a Younger 1.67 is a MR-10, while a Somo 1.67 is a MR-7 (I still want to know what happened to MR-9 and if it's actually used for anything at all. Yes, I know 6 and 8 are 1.60 materials) and it compensates accordingly accross all facets of the lens production, from lens curves, to generator settings, to lens polish times, to laser engraving settings.
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
It is important to remember that the terms "digital surfacing" and "direct surfacing" and "free-form surfacing" actually refer to the very same process: The fabrication of a non-circularly-symmetrical surface using a free-form surfacing process.I've been making that arguement for years now....and even had some success. Unfortunately I think we're still going to be clarifying "Free Form" for many years to come.Those are my definitions and I'm sticking to them until someone convinces me otherwise.
At the end of the day, free-form surfacing is just a manufacturing platform. Contrary to popular belief, there is no inherent benefit of this technology to the wearer, without some form of optical customization. Free-form surfacing can be used, for instance, to produce basic progressive lenses from "points files" that are comparable in performance to traditional, semi-finished progressive lenses. In fact, without sufficient process engineering, it is entirely possible to produce progressive lenses that actually perform worse optically than traditional, semi-finished progressive lenses.
On the other hand, wearers can enjoy significant visual benefits if free-form surfacing technology is combined with real-time optical design software that is capable of optically customizing the lens design for parameters specific to the indvidual wearer, immediately prior to fabrication. This kind of software relies upon complex ray-tracing procedures combined with mathematical modeling and optimization algorithms using data such as the wearer's precription requirements, fitting parameters, frame size, and so on.
Since Essilor prefers the term "digital surfacing," and typically utilizes this technology to produce atoric-like surfaces on the back of semi-finished progressive lens blanks, the term "digital surfacing" has become closely associated with this particular product solution. It is still possible to optically customize a lens design in this manner. The ZEISS Gradal OSD (optimized surface design) and Rodenstock Multigressiv lenses are early examples of this technology. As always, there are both advantages and disadvantages associated with this technology.
Some may argue that placing the progressive optics on the back surface or splitting them between both surfaces affords some optical advantages, but in reality the differences are generaly small due to fact that progressive lenses represent relatively thin optical systems. The greatest optical benefits will be derived from optical customization of the lens design for the specific visual requirements of the wearer.
"Digitally molded," which is another common misnomer exploited by certain lens suppliers, refers to a mold-making process that relies on free-form surfacing or milling the mold, instead of "slumping" the mold over a ceramic former that has been milled using free-form technology. "Digitally surfacing" molds directly has been a very common method of making molds for decades, particularly for the metal molds used with polycarbonate lenses, although certain lens manufacturers have begun capitalizing on the recent interest in free-form surfacing technology by marketing their semi-finished lenses as "digitally molded." There are actually advantages and disadvantages to either approach in terms of manufacturing consistency, ability to replicate certain lens design features, and so on.
Best regards,
Darryl
Darryl J. Meister, ABOM
It is important not to confuse the software settings included in the free-form surfacing equipment with true process engineering conducted by the actual lens supplier. When you install a Schneider free-form surfacing system, for instance, the equipment will have default settings for the cutting and polishing processes, which are selected based upon the lens material. No additional calibrations or adjustments are made for the lens design and prescription combinations of a particular lens supplier, unless the lens supplier performs those calibrations and adjustments.it compensates accordingly accross all facets of the lens production, from lens curves, to generator settings, to lens polish times
Process engineering and ongoing quality verification go far beyond simply changing the refractive index in the calculation software for a different lens material.
Best regards,
Darryl
Darryl J. Meister, ABOM
Back to the original question.... If your ED is not greater than the lens blank diameter, then you can run any de-centered free form single vision or progressive and it will cut out. The optics and laser marks will be de-dentered to the very edge of the blank if required. In any material...
Darryl is right on the mark when he mentioned process engineering. In the Schneider setup the technology in the generators is selected by the LMATID in the VCA data. The newer 103 polishers not only create a "recipie" based on LMATID but also lens diameter and of course the SDF file or BASEX and CROSX values.
It has surprised me how much of the actual success comes from tuning all of the technolgies to your specific needs. These technologies take years of R&D and become the intellectual property of the engineers that develop them.
Be wary of the words "turn key" and "free form machines" in the same sentence.
Last edited by darius; 02-10-2011 at 02:09 AM.
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