# Optical Forums > Ophthalmic Optics >  Scratches!!!

## Dantech

Lately we have been having issues with a large amount of scratches skyrocketing our breakage percentage. We have tried many cloths and have finally settled on disposables which seem to have the best results. We use denatured alcohol as our primary cleaner. Any tips/tricks to reduce scratches would be appreciated.

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## shanbaum

It's probably the software.

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## Dantech

Umm?

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## braheem24

filter your polish, change it often.

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## Dantech

That's one i haven't heard. What do you use to filter it?

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## braheem24

pantyhose at the end of the tube returning to the bucket.

ps not fishnet ;)

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## Georg Mayer

Check also whatever you can find in that pantyhose ( the one at the end of the return pipe obviously...), if it is foreign matter I would suspect the casing and impeller of the polish pump to be on the way out. Stainless pump housing and impellers do help a lot.

However if you still suspect the clenaing cloths the scratches should be fair and square on both sides of the lens, anything related to the surfacing process (...Pantyhose) would naturally be more on the RX surface only.



Better Best than Biggest

Georg Mayer

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## leestaniforth

when you refer to this, are you taking about during ( after fining and polishing) at QC or within or the end of the glazing process?

cheers
lee

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## Ineed Chocolate

> when you refer to this, are you taking about during ( after fining and polishing) at QC or within or the end of the glazing process?
> 
> cheers
> lee


 If I am reading correctly, I think George is speaking of the surfacing process..fining and polishing (I'll be corrected here, if Im wrong :)  Also, in the past, I have found that during fininshing, when the edger arm pushes up against the block to hold the lens in the edger, if you are using a 1/2 eye block in the edger and a full size chuck on the stationary end, sometimes the AR will splinter, making very uniform tiny  lines, sometimes half-moon in shape.  I don't know if I am explaining this correctly, but those fine lines can sometimes be miscontrued as scratches...to me, I noticed it more with Crizal products on very thin lenses (low minus poly or 1.60).

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## Georg Mayer

Yes, correct, I was referring to the surfacing (Fining and Polishing). I

f this is about  edging I can confirm the two types of hairline cracks ocurring in edging mentioned in the previous posting, i.e.
- Center cracks, mostly radial or partially radial on minus lenses with thin CT's. 
- edge cracks coming in sligtly off perpendicular, in pairs or more parallel, extending approx. 1/6 of an inch.

The first ones can be avoided by using just the necessary chuck pressure, working with the largest possible pad, using a pad with a matching base curve, if not available than pad must have a steeper base curve rather. Use  a gentle cut if your machine allows, otherwise you might think about two cuts if you are starting with a large lens cutting down to a small shape.

The second one is of similar nature, stress when the lens hits the wheel the first time, slow cut program or cutting twice, not taking off too much material in one go.

Keep your wheel in good orking order, use the correct wheel suitable for the lens material you are trying to cut.

Georg Mayer

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## William Brown

What type of surfacing equiptment are we talking about and is it in just a certain material. There are so many possible answers-emery pads- polish pads-chilled polish temp.-emery water temp. Running times emery&pol,pressures on the heads.Begin with the generator curve and stock removal? Curves to flat or to strong really are important-check thickness before fining and after fining to check stock removal. Better yet if you want to talk about it give me a # to call. Been surfacing 47years,started with a 390 shuron and now into LOH machinery.Ultra robotic-LOH compact and  SL2 dry cut generator by coburn.

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## Dantech

Thanks guys, Georg i am using a closed loop polish system on each polisher with chiller coils in the reservoir i have a couple ideas on incorporating this filter but  it may be a little more difficult. Leestaniforth it does seem to be more in our finishing/inspecting process the lenses are inspected prior to being hard coated and sent to finish and less scratches seem to come from our surface side. Ineed Chocolate we have experienced the crazing effect on A.r lenses that are run on an incorrect cycle with too much chuck pressure on the edgers but that's not been a huge problem. What i am seeing the most of is light scratches in random areas of the lens front and back leading me to believe some of it is mishandling or bad technique. I have tried several tapes and felt on our lensometers and several cloth/cleaning procedure combos. Was kinda just looking for any suave tricks of the trade i haven't heard of.

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## braheem24

Do you edge glass? are your edgers on recycled water?


You may have a pantyhose fetish by the time I'm done.

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## Dantech

We do not edge glass, we run all dry cut machines that use non recyclable coolant to polish.

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## braheem24

So I cant get you to buy anymore pantyhose?

Wash the lenses before deblocking.

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## William Brown

Yes we do a lot of glass because we have a filtering lense used in detached retinas. All are photo lenses and fired with gas for hours to get the wanted color. We also were a serengeti  lab. We still do them but blanks are hard to come by.We use a tank that needs to be changed so yes we recycle the water but filter it. If I can help you call me at 607-734-4251 and I will share info. Just ask for Bill Brown. I make my own segments and cement them when you can't get certain adds.We laminate glass lenses like 1.70&1.805 for high rxs that need a bifocal.X-ray glass rx's as well.If you can write it I can make it. Love challanges.

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## One science

> Lately we have been having issues with a large amount of scratches skyrocketing our breakage percentage. We have tried many cloths and have finally settled on disposables which seem to have the best results. We use denatured alcohol as our primary cleaner. Any tips/tricks to reduce scratches would be appreciated.


There are some devices now, like a pen, which can help you the scratch.

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## Wes

> There are some devices now, like a pen, which can help you the scratch.


I'm calling BS.

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## lee staniforth

if you have marks on both sides of the lens  there are many possibilities, however it could be poor handling causing the issues. After the lenses have finished the cycle, de-block in water (regardless of diameter) and run under old water straight away. Now inspect the lens and note if the marks are there. Keeping records to record fault at each stage will help you to resolve.

cheers
lee

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## Uncle Fester

> I'm calling BS.


 One science may be referring to a glass brush which I remember from the 70's. It was like a pen with the end having a bunch of glass fibers bundled like an artists flat brush. You could rub it over shallow scratches on glass lenses and it would somehow blend the scratch.

Am I remembering correctly anyone?

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## finefocus

> One science may be referring to a glass brush which I remember from the 70's. It was like a pen with the end having a bunch of glass fibers bundled like an artists flat brush. You could rub it over shallow scratches on glass lenses and it would somehow blend the scratch.
> 
> Am I remembering correctly anyone?


This was the procedure we used to convert flattops to Youngers.

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## optical24/7

> One science may be referring to a glass brush which I remember from the 70's. It was like a pen with the end having a bunch of glass fibers bundled like an artists flat brush. You could rub it over shallow scratches on glass lenses and it would somehow blend the scratch.
> 
> Am I remembering correctly anyone?


When I worked lab back in the 70's we used a super ball cut in half put on a spindle and used rouge to polish out scratches on glass lenses. ( Man I'm getting old...)  :bbg:

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## Dantech

Are suggesting to wash the lenses before deblocking after being edged? After surfacing a lens we do rinse under cold water after deblocking and removing tape.

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## braheem24

Yes and keep a water dip bucket next to handstone to dip the lens after pin bevel too.

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## William Brown

I'm hear to talk the optical business if you want to get together but I'd rather talk on the phone then over the internet. It's hard to communicate different situations on line but I love to talk the optical business. I'm the lab manager so call me at 607-734-4251 anytime 7-4:30 ask for Bill Brown-thank you from downtownbillybrown

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## lee staniforth

asuming that the surface quality is good at taping, the surface quality you refer to (Both sides) can only come from AFTER you remove the surface saver tape.

So.. Once the lenses have finished the polish cycle, Take the lenses from the cyl machine and rinse in water. Then de-block in WARM water upside down in the re-claim tank. Should be set to 60 to stop degeneration of the alloy (cadium burn)  this prevents any contact of the back surface.

Remove the lenses and inspect.

+0044 7826908769

regards
lee

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## William Brown

I believe someone else had the problem and I wanted to recommend suggestions by talking to them on the phone. After all these years I've seen it all. Must be it wasn't important because I never heard from those I gave my # to. Surfacing is a craft that needs attention all the time, so many things can and will go wrong. Happy surfacing everybody and I'm still here for information.

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## DragonLensmanWV

> One science may be referring to a glass brush which I remember from the 70's. It was like a pen with the end having a bunch of glass fibers bundled like an artists flat brush. You could rub it over shallow scratches on glass lenses and it would somehow blend the scratch.
> 
> Am I remembering correctly anyone?


Yes, I used to use those to clean off hardening spots from the chem hardener.

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