I am updating my sourcing for semi-finished spherical blanks, and I find lots of BC choices in the mid to high indexes... which is great.
But I am only finding the 2, 4, 6, 8, 10 base for CR-39 and Poly. I know there is not much money in either of those products, but does anyone know a supplier for the odd number base curves 3, 5, 7, and 9 in spherical CR-39 and Poly?
Thanks, pm if you don't feel comfortable posting.
VE and SA have them in both materials
Thanks Lenny, Vision Ease totally slipped my mind... SA = Signet Armorlite?Originally Posted by LENNY
Lenny, Signet Armorlite had a 3 base in CR-39, but I didn't see a 5, 7 or 9 on their website in UC CR-39 Semi-finished.
CR39
Signet has 0.5, 2, 4.25, 5.25, 6.25, 7.25, 8.25, 9.25, 10.25.
Visionease has 0, 2.25, 4.25, 5.25, 6.25, 7.25, 8.25, 10.25.
Poly
Polycore has 0.75, 1.75, 2.75, 3.75, 4.75, 5.75, 6.75, 7.75, 8.75
Signet has 0.75, 1.5, 2.25, 3.25, 4.25, 5.5, 6.5, 7.5, 8.5, 9.75
Visionease has 0.5, 1, 2, 3, 4, 5.25, 6.25, 7.5, 8.5, 9.75
You can also go with lenses for FF. I think they go in 1D steps.
That is my goal, but this is missing in many CR-39 lines, I guess there is just no money there.
By having lenses in 1D step you will increase $$$ your inventory! And make your life harder!
Theoretically you might be able to find All types of lenses FTs, progressives in 1D steps but they would have to be different brands and/or manufacturers. Are you realy going to achieve that much difference in going 1D steeper or flatter on the lens?
Personally I like 5 and 7 bases for higher RXs. Comes out flatter but still up there comparing to 6 and 8!
Also please dont forget that whatever it says on the box might not be the exact number on the front of the lens!
Yes, good point, boxes don't usually tell you whether the True Base was calculated on the Glass Index 1.53, or on the material index. Most labs in the US still run on the glass index (recalculated by the LMS), but most overseas on the material. With the influx of imported blanks there is likely to be confusion.
We are measuring the Sag for that very reason.
yea, but what does 6 more sets of semi-finished in CR39 really cost? Not that much. Given that my goal is better Optics I do want to have all the base curves available, and I can overnight what I don't carry in stock. Having more BC's allows much more precision on the optics esp in plus powers.
We generally need a few different vendors on hand as most of the digital vendors require the use of their blanks.
We tend to use one vendor to cover most of the base curves, and if one is missing, we can fill in with the other vendors. If you look at the CR39 curves I listed earlier, Signet is only missing the 3 base, and Vision Ease is missing the 3 and 9 base. Shamir, Essilor and Zeiss have a 3 base in their respective digital free form blanks. That pretty much covers the whole range.
Yea, I was hoping to fill on all the blanks from one vendor to keep thickness, diameter and shipping more consistent, and thus power ranges. Its sounds crazy to me that with the low price of manufacturing CR-39 and the flexibility and simplicity of digital, that we have such goofy gaps in the world's most popular lens material.
With multiple vendors the risk of running out meat on that lens increases a bit.
It would look as if Signet Armorlite or Polycore would be your best bet. They both seem to have the best base curve range in CR39. However, they both are missing the 3 base. To me, the 3 base is the least needed, as the plus prescriptions are where we traditionally run into problems.
They both also serve the Polycarbonate range fairly well as well. Vision Ease is a runner up as they are missing the 9 base in CR39.
Carl Zeiss makes 0.50, 2.50-10.50, in 1 diopter steps in their sola line.
They also make, or used to make them in 1 dipoter steps from 1.00-8.00.
edit:
sorry the above is for CR39
For spherical poly they make:
1.00, 2.00, 3.00, 3.75, 4.75, 5.75, 6.50, 7.25, and 8.00
hope those can fill your gaps
Last edited by ml43; 01-06-2015 at 02:54 AM.
Forgive my ignorance, but is poly something that is widely used in the US?
crazy, but true. I had a offered free lens give away coupon and I was shocked at how many ODs ordered Poly for their own eyewear.
Thanks! I forgot about Sola for semi-finished...
Just checked on their availability chart, and I am see Aspheric Poly in those BCs, but not Spherical, in spherical they only list the standard .5, 2.25, 4.50,6.50 and 8.0. but their CR39 selection is good.
<my bad, the call them SV+ in the other base curves, no idea why...
My information on Sola shows they have the gaps in base curves that you were looking to fill. CR39 is missing 3, 7, and 9 in SV, and their digital pucks are missing 7 and 9.
CR39 0.5, 2.5, 4, 5, 6, 8, 10
CR39 Pucks 0.5, 2.25, 3.5, 4.25, 5.25, 6.25, 6.5, 8.25, 10
74mm Poly 0.5, 2.25, 4.5, 6.25, 8
75mm Poly 0.5, 1, 2, 3, 4, 5, 6, 7, 8
My base curve chart has most of those powers, but I will verify its accuracy, it might be old or out of date. Thanks
Vision Ease for both Poly and CR-39.
CR-39: http://www.vision-ease.com/Portals/V...DATED22514.pdf
Poly: http://www.vision-ease.com/Portals/V...Updated614.pdf
CR-39 is 0.00 to 10.25 in roughly 1 diopter steps and Poly is 0.50 to 9.75 in roughly 1 diopter steps.
PS.: I can also verify their quality for use with Free Form as we use them for Shamir (for the designs they doesn't require their own blanks for), Seiko (for the designs they don't require their own blanks for), and IOT.
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 so much!
So, Sola/Zeiss doesn't have a 7.00 or 7.25, but they do have a 7.80 and an 8.00? very Strange.
Essilor has both a 6.25 and 6.50 in the same diameter. Strange again.
Vision-Ease has the most logical and evenly spaced set. Its kind of hodge-podge of BC, diameters.
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