Starting a Poly Rx line need help!!

[lens_man]

Hi everyone!

Ive been processing CR39 prescriptions for the last 5 years and now want to set up a Poly Rx process line. Ive been having problems with the processing of Poly and need some advice on the following :-

The tools that are in use now are cut in .12 steps with an index of 1.498. These tools always give an error in the final Rx while processing Poly. Ive tried all the formulas and calculations that were provided and also some calculators that i had downloaded but havent had any real success. Im sure that ive been making mistakes somewhere but dont know where . Ive decided on cutting a separate set of tools for Poly and need advice on wether i should cut the tools in .10 steps on an index of 1.530 because the front curves are calculated on 1.530 by the blank supplier. I additionally would like to also surface mid index lenses on 1.56 and in future hi-index. Could someone tell me what would be the best tooling steps and in what index would help me in surfacing Poly, mid and hi-index materials?

Another problem ive been facing is cleaning of Poly after surfacing. I presently use Acetone and while using Acetone on Poly the surface scratches. Also while hard coating id like to know what is the acid to be used for etching. We currently use NaOh for Cr. Also i use a 1.55 index Hard Coating solution for CR. I wanted to know if the same can be used for Poly. Coating Poly with the same solution looks okay but i dont know what the effects would be after say 6 months ofuse.

I know most of you people out there have been processing Poly. Please forgive me if the questions asked above are silly but im in need of help especially from the many Gurus like Daryll Harry and others.

Thanks in advance:)

[chip anderson]

Acetone and Poly are not compatable even for "instant" contact.

I use denatured alcohol (although have to know the denatureant as some has Acetone for same) and it works O.K. But I don't surface, just remove marks, etc. Also I once had a gallon of alcohol blow up on me, someone blamed it on the denatureant.

Chip

[gemstone]

Cut a set in .10s at 1.53. You will need that for other high index materials. Software should be able to handle that. Chip is right, no acetone.

[JMoondog]

Most labs I have been in have there laps at 1.53 but most of these labs used those laps for all materials plastic glass poly. My early days of poly cutting 20 years ago, there was always issues with the final product, even with the 1.53 laps.

I found the real devil with poly is the details. Polish types, polish temp. Cutting blades in generator and speeds.

Ric

[Paul van Wyk]

We use the same set of tool for all materials including poly , but we have it in 0.06 steps. It will cost the same to expand the rage to 0.06 steps as it would to make a new set in 0.1 . This will give better results on all materials.

Paul

[Chris Bowers]

Try this fun little utility. It is fairly intuitive

[Bob MacNeil]

Power errors come in any of four different ways: front curve, back curve, lens index, and lens thickness. Rounding of the shop tools for back curve control is often the major problem in powers errors. On this point, the higher the tooling index, the more accurate the curve rounding for lens powers. If the lens index is higher than the tooling index, then it's an up hill battle with lens power.

Bob

[lens_man]

Thanks all who posted replies. And Chris that utility is nice and helps. I guess cutting the tools in .06 would be ideal because i already have tools for CR cut in .12 steps just have to add inbetween.

Do you all think this would be okay for all indexes?

Thanks again.

[humbleABOCtx]

it's been a while sense i've been in the lab...but if you are surfacing don't forget to use diff fining pads for poly + adj. the timing also
(I recall 2 diff grade pads for fining poly) and polishing times are longer I think than cr-39. also make sure the polish is at right temp (not hot) causes more problems for poly.
If you don't have this info --get with the current lab junky's for the details I've been out of the lab way too long.
and yea...acetone is way bad......be a little caution of standard neutralizer too (stess cracks on edge of lens may appear soon after)

[bob_f_aboc]

:angry:Acetone is also bad when someone dumps a bottle of it on your computer tower and seals your CD drive shut, because they didn't see the keyboard on the counter when they set it down with the lid off after cleaning marks off a poly clip-on sunglass.:angry:


:angry:...not that anyone at my office did that this week:angry:

[humbleABOCtx]

I sooooo feel your pain:hammer:

[DragonLensmanWV]

:angry:Acetone is also bad when someone dumps a bottle of it on your computer tower and seals your CD drive shut, because they didn't see the keyboard on the counter when they set it down with the lid off after cleaning marks off a poly clip-on sunglass.:angry:


:angry:...not that anyone at my office did that this week:angry:

Mwahhahha! I paid them to do that.

[bob_f_aboc]

Mwahhahha! I paid them to do that.

:angry:If you had told her to do it, it never would have happened!:angry:

[Fezz]

:angry:If you had told her to do it, it never would have happened!:angry:

She seems FUNEE!!

TEE-HEE!


:cheers::cheers::cheers::cheers::angry:

[Georg Mayer]

Most of the discussion was lens and power related, which is the basis to get a good lens out of the workshop in the first place.
The other issues you raised were cleaning scratches and Hard coat.

Discipline, cleanness and staff awareness training is the only help to combat avoidable unnecessary scratches through negligence in handling (dirty cloths, dry rubbing etc).

The chemistry in treating and coating Poly is fundamentally different to the conventional organic materials you might have.
Etching in caustic has practically no effect and your suspicion is right, it might look good but 6 months down the line your head will be on the block. I don't know which equipment (Dip - spin) you use and which lacquer you have, but speak to your supplier now and get the right lacquer/chemistry suitable for PC. You might get away with priming the PC and then proceed into your standard system, you might have to set up a small spin coat unit for PC (UltraOptics MR III with UVNV works well), but don't carry on coating PC with the standard 1,5-1.6 index procedure and chemistry!

Georg Mayer

[albednar]

Hi everyone!

Ive been processing CR39 prescriptions for the last 5 years and now want to set up a Poly Rx process line. Ive been having problems with the processing of Poly and need some advice on the following :-

The tools that are in use now are cut in .12 steps with an index of 1.498. These tools always give an error in the final Rx while processing Poly. Ive tried all the formulas and calculations that were provided and also some calculators that i had downloaded but havent had any real success. Im sure that ive been making mistakes somewhere but dont know where . Ive decided on cutting a separate set of tools for Poly and need advice on wether i should cut the tools in .10 steps on an index of 1.530 because the front curves are calculated on 1.530 by the blank supplier. I additionally would like to also surface mid index lenses on 1.56 and in future hi-index. Could someone tell me what would be the best tooling steps and in what index would help me in surfacing Poly, mid and hi-index materials?

Another problem ive been facing is cleaning of Poly after surfacing. I presently use Acetone and while using Acetone on Poly the surface scratches. Also while hard coating id like to know what is the acid to be used for etching. We currently use NaOh for Cr. Also i use a 1.55 index Hard Coating solution for CR. I wanted to know if the same can be used for Poly. Coating Poly with the same solution looks okay but i dont know what the effects would be after say 6 months ofuse.

I know most of you people out there have been processing Poly. Please forgive me if the questions asked above are silly but im in need of help especially from the many Gurus like Daryll Harry and others.

Thanks in advance:)

You raise a number of excellent questions pertaining to your entry into poly processing. First in regards to the tools. Since you stated that you are thinking of cutting a set of tools specific to that material as well as some high index materials, I would suggest cutting the new tools to a 1.60 index. This is fairly close to a one to one match of the index of the material including your other high index choices. This will give you better rounding for more accurate through powers. 10th increments are the norm these days. You may even elect to cut without the old pad compensation and just allow the software to take care of the mathematics.

For cleanup, acetone is a definite no since it aggressively attacks raw substrate even the edges after hard coating. There are a number of good "poly friendly" cleaners available from various suppliers. Contact your normal supplier for suggestions.

[shanbaum]

With regard to laps, here's a thread you might find interesting (from 2003!):

http://www.optiboard.com/forums/showthread.php?t=7157