# Optical Forums > Ophthalmic Optics >  Surfacing Troubleshooting

## IChen

Hi! New participant in the OptiBoard community, I would like to give my greetings and also present to you problems I am having with setting up our surfacing lab. Below I've listed the equipment and materials we are currently using as well as pictures of a couple of our problems;

Blocker - Optek Unity Max Blocker (Wax)
Generator - Optek SL Profile
Finer/Polisher - Optek 425 Surfacer
Lens - Sola PolyCarb SFSV 74mm 6.25base 
Lap - Plastic
Water and Polish is chilled to 60°F
Surfacing Process - 2 step -   1st Step - PSI P280, high speed for 1 minute @ 19.8psi
                                                                              2nd Step - 15um Orange Strip (Optifilm/Durafilm), high speed for 2 minutes @ 19.8psi
                                                                                       Polish - Clearly Digital (3300G from PSI) + Maize HD Polish Pad from PSI, high speed for 6 minutes @ 19.8psi



In this picture, there are these very small scratches visible in the reflection, what causes these? Increasing fining time/pressure and/or increasing polishing time/pressure did nothing. Would this be an acceptable lens?

And another concern is that we still have some fining marks (scratches) on the very outer perimeter of the lens, about 1/6th of an inch in, visible when checking with our Bulbtronic. These scratches only went away when we increased our polishing time to 10 minutes. However, 10 minutes polishing time is hardly acceptable so we would like to reduce that.

And finally, if you look closely at the reflection on the lens, you can make out the outline of a fining pad. Are we at too high of a pressure or are there any other reasons to see something like this?


If you would like any additional information, please let me know and I will post it as soon as I can. 

Thank you for your time and any assistance would be greatly appreciated!

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## Wes

Are you using recycled water or fresh?
if that head pressure or machine pressure?
Does the generator give a relatively smooth finish?

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## IChen

I am using recycled water, filtered through a coarse mesh and a pantyhose.

The pressure I gave (19.8psi) is the head pressure, the machine pressure is 50psi.

The generator, in my opinion, gives a relatively smooth finish.



Sorry about the picture quality! Hopefully it does show a little bit of the finish the generator is providing.
This is a CR-39 lens, unfortunately I do not have any generated polycarbonate at the moment, but the finish is pretty close with the exception of the center nub is larger in polycarbonate lenses.

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## Wes

My first thought is that the water is contaminated.  Second thought is maybe the polish is, but the fact that ten minutes of polishing gets rid of the issue indicates it's the water.  Is this a new problem or an ongoing one?  Try changing the water and check your filtration.

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## IChen

I believe you are addressing the 2nd issue I am having? The one about fining marks on the perimeter of the lens? This is an ongoing issue, we've changed the water and we still have the issue. The filtration system (coarse mesh + pantyhose) is the same setup for both our water and polish. I've checked both the mesh and the pantyhose and I am not seeing any coarse particles or chunks caught inside.

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## Wes

Its hard to make a good call based on grainy internet pictures.  If your generator is off axis, or the cutter is slightly off center,  it can leave small areas on the edges that don't easily fine out.  This also leads to more wear on fining pads.  Worn pads can lead to debris in the water.  
Does this happen with spherical jobs and clean water?

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## IChen

Yes, this does occur with spherical jobs and clean water. We've also tried to check to see if our generator was off by coloring in a lens with sharpie and fining for 10 seconds, there were a couple of spots where the sharpie faintly remained but they were about a 1/2 inch in from the perimeter of the lens while the scratches we're finding are in the very extreme ~1/6 inch.

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## RT

Does your generator support cribbing?  The lenses pictured do not appear to be cribbed.  That will almost certainly improve issues near the perimeter of the lens.

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## IChen

Yes my generator does support cribbing, and you are correct the lenses are not cribbed. We only have the PCD cutter (Optek 8300-348) that came with the generator so we do not have a fluted cutter. We have already ordered one and eagerly await its arrival. I suspect the cribbing will indeed improve or eliminate the issues near the perimeter of the lens, but what about the other two issues I am having?

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## fjpod

I have virtually the same setup.  We crib lenses first on an old Optronics 3...it's just easier.  Cribbing is important.

Let me ask a stupid question about those hairline scratches...Are you rubbing the poly lens after polishing and rinsing it?  those marks look more like someone took a towel to the lens to dry it off.

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## IChen

I'm not rubbing the poly lenses after polishing and rinsing it, I can't say what our techs are doing but they shouldn't be. All the lenses I'm taking into consideration at the moment are ones I've personally handled though. We dry/clean our lenses with kimwipes (delicate task wipers, http://www.amazon.com/Kimberly-Clark.../dp/B00006IAUT) and 99.9% IPA. I suspect those hairline scratches to be coming from the fining or polishing process since as you can see in the picture, they are in a circular pattern. I would imagine if it was handling or a towel causing the scratches, the scratches would be more linear? I'm just really puzzled by this issue as we've swapped several different polishes and we consistently see this issue, though at varying intensities (amount of hairline scratches).

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## WFruit

Pardon if these questions seem basic or elementary, but I prefer not to assume anything in situations like this.

I'm not as familar with those finers/polishers but others that I've used over the years usually run ~18 psi.  

Since these are poly lenses, do you still see the scratches after they have been backside coated?  

Is it possible you're getting debris from somewhere onto the pads (probably polish)?  Do you start the cycle with the pads wet or dry?  Wet not only helps start the process a little more smoothly, but can rinse off any debris on the pads.  

Have you contacted PSI to see if they have any recommendations?  You're using a lot of their products so they may have tips you can try.

Are you rinsing/drying the lenses between fining and polishing to make sure the lenses are fined out completely?  This may help determine if the issue is fining or polishing specific.

For the edge fining marks, cribbing will defintely help, as it sounds like the lens is flexing in the generator.  Or it could be your tools are old.  You said they are plastic tools, how old are they, and are you sure of their accuracy?

Oh, and welcome to Optiboard.   :Smug:

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## fjpod

What about your fining?  Fining a little longer will probably get rid of those edge marks...but it may affect your center thickness, so watch out.   Also, your blade may be cutting a tad flat.  Have you done a 7 second test?  IOW, generate a lens with a -6.00 curve.  with a black sharpie draw four or five spoke like lines through the center of the lens.   then fine it for 7 seconds on a 6 lap tool.  The black lines should wear out somewhat equally in the center as well as the periphery.  If not, or iif the periphery is not wearing, then you need to adjust your blade radius calibration.

Im not familiar with the second fine pad you mention.  We use the PSI black first fine, and brown second.

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## braheem24

what size are your laps in diameter? ...and do the fining petals cover the lap fully?

I would try increasing time on lower speed

2min 1st fine
3min 2nd fine
4 min polish

all on low speed.

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## IChen

Wow, a lot of responses! Thanks for the warm welcome and the help! Sorry about the late replies, I just got home now and am responding as fast as I can.

WFruit:

Since these are poly lenses, do you still see the scratches after they have been backside coated?  

I'm not sure if the scratches will be filled in by the coating or not as we are a surfacing lab and will not/cannot coat anything.

Is it possible you're getting debris from somewhere onto the pads (probably polish)?  Do you start the cycle with the pads wet or dry?  Wet not only helps start the process a little more smoothly, but can rinse off any debris on the pads.  

A definite possibility, we're using a coarse mesh and a pantyhose to filter both our water and our polish, and I've checked both filtration systems and neither one has anything that stands out (besides from the usually gunk you catch in the water and the settled polish abrasive from the polish). We start the fining cycle wet by turning on the water before placing the lens on, and same with the polish, we even rub the polish into the pads with our fingers too. 

Have you contacted PSI to see if they have any recommendations?  You're using a lot of their products so they may have tips you can try.

I've already contacted them a couple times, both times they've given pretty standard condition recommendations (12-18psi @ 1-2 minutes for each step) and then asked me to check my filtration. I've yet to contact them a third time as the last time they just asked me to double check the filtration again.

Are you rinsing/drying the lenses between fining and polishing to make sure the lenses are fined out completely?  This may help determine if the issue is fining or polishing specific.

Yes we are rinsing and drying (with a kimwipe and 99.9% IPA) the lenses, after the 1st step we will occasionally see some very faint generator marks (not detectable to touch though [running my fingers over it]), and after the 2nd step we will not see any generator marks detectable with the naked eye. 

For the edge fining marks, cribbing will defintely help, as it sounds like the lens is flexing in the generator.  Or it could be your tools are old.  You said they are plastic tools, how old are they, and are you sure of their accuracy?

Now that you mention it, the tools are pretty well loved, I'm not so sure about their age as we purchased our set used, and therefore am not comfortable in stating their accuracy. In that case I will definitely get one re-trued and test it out.

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## IChen

> What about your fining?  Fining a little longer will probably get rid of those edge marks...but it may affect your center thickness, so watch out.


This is exactly why I haven't extended the fining time, I feel much more comfortable lengthening the polish time. I will go back and increase the fining time on the 2nd step by 30 seconds and see if that will  fix the problem without affecting center thickness too drastically.




> Also, your blade may be cutting a tad flat.  Have you done a 7 second test?  IOW, generate a lens with a -6.00 curve.  with a black sharpie draw four or five spoke like lines through the center of the lens.   then fine it for 7 seconds on a 6 lap tool.  The black lines should wear out somewhat equally in the center as well as the periphery.  If not, or iif the periphery is not wearing, then you need to adjust your blade radius calibration.


I've done something similar to a 7 second test where I generate a -6.00 curve and color in the lens with sharpie, and 1st step fine for 10 seconds on a 6 lap. Everything except for 2 very faint sections maybe 1/4" x 1/2" about 1/2" in from the perimeter fined out. This seemed acceptable to me, do you think I should just go ahead and adjust my blade radius calibration (And any recommendations  :Biggrin: )? 




> Im not familiar with the second fine pad you mention.  We use the PSI black first fine, and brown second.


15 micron 3M Optifilm/Durafilm is advertised as a 1 step for CR-39/hi index or as a 2nd step for polycarbonate. I can take a picture of it when I get back to work tomorrow but its pretty distinct, white-greyish with orange strips.

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## IChen

> what size are your laps in diameter? ...and do the fining petals cover the lap fully?


I'm not currently at work at the moment so I cannot say exactly what they are, but I think they are 3.5" as they are larger than my 3" pads. So no, my fining petals do not fully cover the lap. I didn't think it would be an issue as I made sure the stroke of my fining machines did not cause the lens to go over the edge of the lap (Seen dings on the edge of the lap cause scratches when the lens goes over them).




> I would try increasing time on lower speed
> 
> 2min 1st fine
> 3min 2nd fine
> 4 min polish
> 
> all on low speed.


I'll definitely give that a shot as soon as I can and report back my findings! Thanks for the recommendations! Also just a quick side note, my finers only have 3 settings; high, low, and play dead (kidding about the 3rd one! it only has high or low) so I might consider increasing fining/polish times even more just to see if lower speed eliminates my problems.

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## Jubilee

A few thoughts here:

1) Surfacing poly, but not coating? I was always thought this was part of the surface side if you will. Offices will expect the lens to be coated and ready to edge if ordering "uncuts."  Poly will always have some faint scratches/marks due to the nature of the material. A simple wipe off with even a microfiber cloth will leave marks. Btw.. the marks will resemble your cleaning pattern. So if they are being cleaned in a circular patter, the marks will be circular.

2) If you reduce the speed to low, you take off less material over the same period of time compared to high. Think of it more in terms of how many strokes and orbits it makes over the pad. So increasing the length of the finer cycle, but reducing the speed will not affect the thickness much unless you more than double the length of time. 

3) I am on the same page as braheem thinking that perhaps by increasing the time and using a low setting should give a smoother surface. Think of it like using sand paper. For a rough fine, hard and fast works great, when you want to create a nice smooth finish, usually slower and deliberate works better.

4) If you still have some marks after trying braheem's you might kick up the polish time by a minute more.

5) I can't believe no one has asked.. but is this only occuring with poly?

6) How many jobs a day are you averaging, and how often do you change the polish? Do you check the baume'?

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## IChen

> A few thoughts here:
> 
> 1) Surfacing poly, but not coating? I was always thought this was part of the surface side if you will. Offices will expect the lens to be coated and ready to edge if ordering "uncuts."  Poly will always have some faint scratches/marks due to the nature of the material. A simple wipe off with even a microfiber cloth will leave marks. Btw.. the marks will resemble your cleaning pattern. So if they are being cleaned in a circular patter, the marks will be circular.


After reading this comment, there is now a little bit of doubt in the back of my mind, but I am still about 95% confident that handling/cleaning is not the cause of these hairline scratches. I shall pay even more extreme attention to this the next time we polish a lens to triple check if it truly is our handling. 




> 2) If you reduce the speed to low, you take off less material over the same period of time compared to high. Think of it more in terms of how many strokes and orbits it makes over the pad. So increasing the length of the finer cycle, but reducing the speed will not affect the thickness much unless you more than double the length of time. 
> 
> 3) I am on the same page as braheem thinking that perhaps by increasing the time and using a low setting should give a smoother surface. Think of it like using sand paper. For a rough fine, hard and fast works great, when you want to create a nice smooth finish, usually slower and deliberate works better.
> 
> 4) If you still have some marks after trying braheem's you might kick up the polish time by a minute more.


Okay I'll try this recommendation first before I mess with anything else! Thanks!




> 5) I can't believe no one has asked.. but is this only occuring with poly?


Well, can you believe I didn't think about including my results on CR?  :Banghead:  We currently only work with poly and CR39, and looking back it just makes me feel even stupider for not including the results for CR as well. Anyways, I'm not currently at work and it is a bit too late to call my colleagues and ask about it, but from what I roughly remember it is also occurring on CR as well. Please let me double check this, as I have a feeling it is pretty important and I tend to doubt my memory when it comes to remembering things.




> 6) How many jobs a day are you averaging, and how often do you change the polish? Do you check the baume'?


We've still trying to get the lab set up (about 2 weeks now), but I think we average about 10 - 15 jobs a day. We're still trying to nail down the process, conditions and consumables, so we probably change the polish every 5 jobs (suspecting the polish so cycling through them to see if we can find one that eliminates our issues). We currently do not check the Baumé due to us changing polish so much and also since we're cycling through polish, I rigged the polisher to only use a little less than a liter (33.8oz) of polish.

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## fjpod

You should remove all generator marks with the first fine. Do not proceed to second fine unless all marks are gone.

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## Jubilee

hmm. And with the liter of polish, is flow always a nice steady amount? I would hope that it isn't so contaminated after 5 jobs that it would produce results like this. I seriously doubt it with the use of the makeshift filter.

I know that you aren't able to crib right now, though the fluted cutter is on its way. For now, are you at least touching off the lens on the handstone to give it a nice bevel edge to reduce swarf/crumbling, and to remove part of the lip to allow water/polish to get under the lens and more on the pad?

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## IChen

Ha! Combined two responses into one! Getting smarter!  :Smug: 




> You should remove all generator marks with the first fine. Do not proceed to second fine unless all marks are gone.


The vast majority of the time, I would say about 95% of the time, all generator marks are gone (not visibly detectable with the naked eye) by the first fine, and the 5% that it's not, you can barely see, cannot feel it, and it is not there after the second fine. I wanted to idiot proof my process by just having anyone in the lab able to use the cylinder machines and just fine the lens for whatever the machine is set to but it's starting to look like a pipe dream, especially if I can't get around these issues.




> hmm. And with the liter of polish, is flow always a  nice steady amount? I would hope that it isn't so contaminated after 5  jobs that it would produce results like this. I seriously doubt it with  the use of the makeshift filter.


Ah, I figured someone would ask  about that, but didn't include that in my last response as I seemed to  getting kind of wordy. But yes, polish is at a constant flow, so that is  definitely not an issue. I don't think it is contaminated as when we  swap polishes I always have someone check the filtration (mesh and  pantyhose) for anything strange beside the usual settled polish gunk. 

Also a quick question, I was under  the impression that tying a pantyhose was a pretty typical  quick/effective way to filter your water and polish, was I wrong? I do  have some other filtration media of various sizes (255μm, 185μm, 125μm, 100μm, 75μm, 55μm, 25μm, 10μm, and 5μm)  available, I just wasn't sure if that was necessary as the typical size  of most polishes is 1.3 microns with a range of maybe up to 6 microns  (and up to 13 microns for cheaper polishes).  I also didn't want to be filtering too small and end up plugging my  recirculation system and having to constantly clean my filter, if it  plugs up quickly in my system of 1 liter, I'm scared to imagine what  would happen once I go back to a gallon or more. But I'm definitely  willing to experiment at this point, solving the three issues I've  listed in this thread is my top priority, I can optimize my process  later once I've eliminated my issues. Should I be changing my filter to  something else? And what would you recommend? 




> I know that you aren't able to crib right now, though the fluted cutter  is on its way. For now, are you at least touching off the lens on the  handstone to give it a nice bevel edge to reduce swarf/crumbling, and to  remove part of the lip to allow water/polish to get under the lens and  more on the pad?



Uh, no I'm not touching off the lens on a handstone  :Redface: . It's partly due to not having one, but mostly due to me not even thinking about it, sorry. This will be the 1st thing I try when I get into the lab!

Seems like I got wordy again, sorry about that! Thank you for all the responses, I'll get to work on your suggestions and report back with my results as soon as possible!

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## WFruit

Unless your generator is putting a safety bevel on the lenses (which it sounds like it isn't), then you MUST touch them off by hand.  Not only will you not cut your hands, but you won't tear up your fining/polishing pads, AND it allows the water/polish to flow under the lens.

I'm with Jubilee in being shocked you don't backside coat poly! 

I've used pantyhose to filter polish, though I've had fresh water in every lab I've worked in (retail and wholesale).  The last place I had to worry about it was at a retail chain location lab.  I did 100~150 surface jobs a week there and changed the polish and pantyhose about 1/week.

Silly question about the polish, but are you stirring it on a regular basis?  Running so few jobs I'd give it a quick stir before each one, just to make sure the polish particles haven't settled too much.  Otherwise you're pretty much polishing with white water...

First fine should completely remove the generator marks EVERY time.  One the ones where it isn't, I'd be curious to know, after fining and polishing, if the lenses were still on power.  That sounds to me like the lap curves may be worn.  Try to keep an eye on which tools give which results.

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## IChen

> Unless your generator is putting a safety bevel on the lenses (which it sounds like it isn't), then you MUST touch them off by hand.  Not only will you not cut your hands, but you won't tear up your fining/polishing pads, AND it allows the water/polish to flow under the lens.



No we're not putting a safety bevel on the lenses, I was under the impression the bevel and/or cribbing was mainly to improve fining/polishing quality by allowing more water/polish to flow under the lenses as well as less surface area to work with. Do you put the safety bevel on the lenses as well crib? or is it one or the other?




> I'm with Jubilee in being shocked you don't backside coat poly! 
> 
> I've used pantyhose to filter polish, though I've had fresh water in every lab I've worked in (retail and wholesale).  The last place I had to worry about it was at a retail chain location lab.  I did 100~150 surface jobs a week there and changed the polish and pantyhose about 1/week.


It shouldn't be too much of an issue to hook water into our machine and have fresh water rather than recirculated, I'll go ahead and work on that and see what happens.




> Silly question about the polish, but are you stirring it on a regular basis?  Running so few jobs I'd give it a quick stir before each one, just to make sure the polish particles haven't settled too much.  Otherwise you're pretty much polishing with white water...


Yes, we just stick a tongue depressor in there and stir it up before every job we polish.




> First fine should completely remove the generator marks EVERY time.  One the ones where it isn't, I'd be curious to know, after fining and polishing, if the lenses were still on power.  That sounds to me like the lap curves may be worn.  Try to keep an eye on which tools give which results.


I'll have to look into this and get back to you, but the laps I were working with were 6's, which really bothers me since it wasn't something more extreme like a 2 - 3 or a 11 - 12.

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## Darryl Meister

This may have already been mentioned in one of the above posts, and I apologize in advance if this post is redundant, but you may be able to tell the source of the "scratches" by inspecting the actual pattern and texture of the scratches.

Generator marks that have not completely fined out will have a more consistent pattern (spirals for a 3-axis generator, parallel curves for a 2-axis generator) and are more "sleek." Random and more jagged scratches or "swirls" would be more indicative of contaminated water or slurry during fining or polishing.

If you haven't already done this, inspecting the lens surface carefully under an arc lamp or in a shadow box between each step of the process might also help you isolate the source of the scratches. And, of course, obvious issues, such as tears in polishing pads.

I have seen several very good recommendations above regarding cribbing and chamfering the lens blank to improve water and slurry flow. Remember that over-polishing to work around this issue, in addition to reducing throughput, can lead to other unwanted problems, such as waves and polishing burn.

Best regards,
Darryl

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## IChen

Not at all, thanks for taking the time to provide your expertise on my issue.




> This may have already been mentioned in one of the above posts, and I apologize in advance if this post is redundant, but you may be able to tell the source of the "scratches" by inspecting the actual pattern and texture of the scratches. 
> 
> Generator marks that have not completely fined out will have a more consistent pattern (spirals for a 3-axis generator, parallel curves for a 2-axis generator) and are more "sleek." Random and more jagged scratches or "swirls" would be more indicative of contaminated water or slurry during fining or polishing.


My 1st issue (hairline circular scratches) I'm puzzling over as I haven't seen such a pattern before, they are not swirls nor are they random. They are also extremely faint and only visible under the reflection of an arc lamp, you can only see them if you look directly at the lens while reflecting the light of the lamp off the lens.

My 2nd issue (scratches and sometimes swirls on perimeter of lenses) seems pretty commonplace, most likely due to lack of cribbing and chamfering of the lens blank. They are also only visible when the lens is held perpendicular to under an arc lamp.

My 3rd issue (imprint? of a fining or polishing pad) I haven't seen this type of defect before, the imprint is only visible under the same conditions as the 1st conditions but at a different angle. The imprint seems to be made up of tiny hairline scratches.

So lucky me, all 3 of my issues has to do with scratches, but in my opinion none of them are generator marks. I can try to get some better images, maybe bring in a better camera or something if anything thinks it will help.




> If you haven't already done this, inspecting the lens surface carefully under an arc lamp or in a shadow box between each step of the process might also help you isolate the source of the scratches. And, of course, obvious issues, such as tears in polishing pads.


Pardon my ignorance, but what and how exactly do you use a shadow box? I did a little google-fu and found that a shadow box is a wall mounted mirror (or a box of makeup)? I can imagine how it's used but my google-fu didn't really help me much on shadow box usage. Unfortunately no obvious issues such as tears in fining pads or polishing pads, nor did I find anything which I would consider significant in my filtration.




> I have seen several very good recommendations above regarding cribbing and chamfering the lens blank to improve water and slurry flow. Remember that over-polishing to work around this issue, in addition to reducing throughput, can lead to other unwanted problems, such as waves and polishing burn.
> 
> Best regards,
> Darryl


I am actually a little excited about going into work Monday, I have all these recommendations to try out! I will update the thread with my findings as soon as possible! Thanks!

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## Darryl Meister

> Pardon my ignorance, but what and how exactly do you use a shadow box?


The device may go by different names. I've always known ours as a "shadow box" or a "shadow scope." It is basically a bright lamp, I believe with some sort of collimating lens, which is used to illuminate a lens under inspection while it is held over a matte white screen. Common surfacing defects in the lens show up on the screen as faint shadows.




> My 1st issue (hairline circular scratches)


I noticed these in your first photo, which is why I brought this up. Several suggestions pertained to contaminated water or slurry, although I wouldn't have expected this kind of pattern due to the more complex movement of a cylinder machine head. But, in all fairness, I haven't done any lens surfacing in years.

I would consider any stages in your process that might involve rotational movement or contact against a rotating part. For instance, since you're using a 3-axis generator, I imagine that they could be generator marks. If so, you should detect these marks on the lens surface after the first fine.

Even something as simple as cleaning the uncoated lens surface with a circular wiping motion may be the cause.

Best regards,
Darryl

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## IChen

> The device may go by different names. I've always known ours as a "shadow box" or a "shadow scope." It is basically a bright lamp, I believe with some sort of collimating lens, which is used to illuminate a lens under inspection while it is held over a matte white screen. Common surfacing defects in the lens show up on the screen as faint shadows.


Ah, so a shadow box/shadow scope is the same thing as an arc lamp? We have a Bulbtronic, basically an arc lamp which shines onto a flat platform so you can hold a lens parallel to the platform and see the shadows, so I think we're talking about one and the same. This makes me curious as to what the hell this thing is then; http://www.veatchinstruments.com/pro...?ic=CPCO06-000.




> I noticed these in your first photo, which is why I brought this up. Several suggestions pertained to contaminated water or slurry, although I wouldn't have expected this kind of pattern due to the more complex movement of a cylinder machine head. But, in all fairness, I haven't done any lens surfacing in years.
> 
> I would consider any stages in your process that might involve rotational movement or contact against a rotating part. For instance, since you're using a 3-axis generator, I imagine that they could be generator marks. If so, you should detect these marks on the lens surface after the first fine.
> 
> Even something as simple as cleaning the uncoated lens surface with a circular wiping motion may be the cause.
> 
> Best regards,
> Darryl


Yes, now that I think more about, the cylinder head has a much more complex movement than just a circular motion, and the hairline circular scratches in my 1st picture are just that, just very faint scratches about 1mm long going into a circle. I've gotten so many recommendations to check our handling/cleaning of lenses that I'm getting very paranoid. I might even just start having people rinse the lens and then blow them off with an airgun or something...

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## uncut

@IChen: 

The article that you were wondering about in Post #28 is a mirror used in a refracting lane.  The mirror is usually front-side "silvered", and is adjustable at all corners in order to reflect a projected chart image for viewing.

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## IChen

> @IChen: 
> 
> The article that you were wondering about in Post #28 is a mirror used in a refracting lane.  The mirror is usually front-side "silvered", and is adjustable at all corners in order to reflect a projected chart image for viewing.


Oh wow, I just realized, a projected eye chart screen. Duh. Well guys, good example of my uhhh...airheadedness? I'm not sure of the word I'm looking for but you can go ahead and fill in the blank for me, thanks.

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## uncut

Welcome to the Forum, IChen.  No need to feel airheaded.........we all are a-learnin' as we go in life.................and we all have those "DOOH! moments.  I wish you success in finding the source of the circular scratches.  

I assume that they are on the back side of the lens?
Are there any airborne sources of polycarb dust/swarf with in the room?(Just thinkin' out loud)

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## IChen

Yeah I understand too, I can totally understand a couple of "DOH!" moments but when you're getting several a day, something's wrong and you start feeling not too bright. Also it's more like relearning, I've been taught it, I just don't remember it until someone points it out or smacks me in the face with it.  :Banghead: 




> Welcome to the Forum, IChen.  No need to feel airheaded.........we all are a-learnin' as we go in life.................and we all have those "DOOH! moments.  I wish you success in finding the source of the circular scratches.  
> 
> I assume that they are on the back side of the lens?
> Are there any airborne sources of polycarb dust/swarf with in the room?(Just thinkin' out loud)


Yes, you're assumption is correct they are only on the back side of the lens. The only 2 sources of polycarb dust/swarf becoming airborne would be the generator (which has a working vacuum system) and also the vacuum system for the generator which is unfortunately in the same room, so if the filter on the vacuum isn't on right or clogged I guess it could be shooting some stuff into the air. I would think I would notice if it was putting stuff into the air as I kinda stuck my face in the exhaust when I was getting it set up to make sure it wasn't. I also put a bag over the exhaust while we did a couple of jobs to double check but I didn't find anything in the bag so I think we're good.

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## fjpod

FWIW, I use recirculated water in my finer.  We change it out every 10-15 jobs or so, but I really don't see that it makes too much difference in results.  If anything, water with a lot of lens material in it just acts likes more of an abrasive...but I still recommend changing it out.

We have at times not put safety bevels on lenses and saw no difference in results, but again, I recommend it.

Cribbing on the other hand, does show improved results in that lenses finish faster and the perimeter of the lenses come out better.

I still think those hairline scratches look like they are from toweling the lens.

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## IChen

Thanks a lot for your input, I'll be testing out some of the recommendations made in this thread and it definitely helps to have someone else's results to compare against. Unfortunately I won't be able to do anything with cribbing until we get that fluted cutter in so I'll just have to work around that for now. The hairline scratches I'll verify tomorrow if it is due to handling and report my findings as soon as possible.

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## IChen

Sorry about not updating yesterday, got called away from the lab. Today I only got to play with 1 job and the option available/chosen was lighter pressure and it doesn't look like I'll have much time to try anything else for the timing being. Anyways, onto my results. 

Machine was flushed and water replaced with fresh water, slurry is used but stirred before use. Lens was rinsed and air dried and examined between each step.

1st Fine: P280 for 2 minutes @ 16psi on high, stock removal of 0.164mm
2nd Fine: 15um Optifilm for 2 minutes @ 16psi on high, stock removal of 0.016mm
Polish: Clearly Digital (3300G from PSI) + Maize HD Polish Pad from PSI, 6 minutes @ 16psi on high, stock removal of 0.016mm

Results were better than initial results posted but all 3 issues are still present. The amount of hairline scratches have been reduced but there are still present and still in the same pattern as reported earlier (circular). The scratches and swirls on the perimeter of the lens have been reduced, but still present as well. And finally the imprint of a pad is still faintly visible, but much harder to see. 

So from this job I think it is safe to conclude that the hairline scratches are not handling scratches nor are they coming from the water. The slurry was only used for 3 jobs before this, so unlikely, but still a possibility for some sort of contamination. 

And for the benefit of anyone unfamiliar with my 2nd step; http://www.1-800-optisource.com/1-St...ge-Stripe.aspx. 

Also this pad can be used for one step fining of CR-39 (I use a compensated version for this), I use it for 2 minutes @ 19.8psi on high followed by 6 minutes polish with the same conditions and no issues with CR, so polycarb is the only material (I only do CR and poly anyways) which these issues present themselves in.

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## fjpod

> Sorry about not updating yesterday, got called away from the lab. Today I only got to play with 1 job and the option available/chosen was lighter pressure and it doesn't look like I'll have much time to try anything else for the timing being. Anyways, onto my results. 
> 
> Machine was flushed and water replaced with fresh water, slurry is used but stirred before use. Lens was rinsed and air dried and examined between each step.
> 
> 1st Fine: P280 for 2 minutes @ 16psi on high, stock removal of 0.164mm
> 2nd Fine: 15um Optifilm for 2 minutes @ 16psi on high, stock removal of 0.016mm
> Polish: Clearly Digital (3300G from PSI) + Maize HD Polish Pad from PSI, 6 minutes @ 16psi on high, stock removal of 0.016mm
> 
> Results were better than initial results posted but all 3 issues are still present. The amount of hairline scratches have been reduced but there are still present and still in the same pattern as reported earlier (circular). The scratches and swirls on the perimeter of the lens have been reduced, but still present as well. And finally the imprint of a pad is still faintly visible, but much harder to see. 
> ...


Call PSI.  Ask them for samples of their Black/Brown first and second fine pads for poly.  Tell them your problem and that a satisfied PSI customer recommended that you call.

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## LLano

IS there a trick to balancing and "re-belting" an Accuity cyl. Machine??? We had a leak under one or both spindles and when gaskets were replaced and gear pulleys placed under newly gasketed spindles the belt keeps riding up <(quickly). Any wisdom?

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## theGross1

> IS there a trick to balancing and "re-belting" an Accuity cyl. Machine??? We had a leak under one or both spindles and when gaskets were replaced and gear pulleys placed under newly gasketed spindles the belt keeps riding up <(quickly). Any wisdom?


A little late but there are some set screws that go into the gear to hold it in place.


As for OP.  I hope you have solve your problem by now but I would suggest you check the curves of your generated lens to make sure it's cutting true and also check the curves on your laps

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## albednar

It has been a while since I have been on OptiBoard and this problem immediately caught my eye. I have read through all the posts and everyone offers great suggestions. I would like to share my personal experience with the 2 step pad combo you are currently using. I believe that the 15 micron orange stripe pad is not nearly aggressive enough to effectively smooth the surface coming off of a P280 first step. I would suggest trying something a bit less aggressive on your first step such as a P400. It is still quite aggressive, but will leave a better finish for the 2nd step to do its job more effectively. My recommendation for your second step would be more in line with a pad such as a P1000 or P1200.

All of your other surface parameters look right where they need to be.

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## IChen

Over half a year, I always told myself if I made an account I wouldn't abandon threads, not enough discipline apparently. Sorry guys  :Frown: . 
A long overdue update, the scratches and fining marks on the rim of the lenses was fixed by swapping to some aluminum laps, it seems the plastic ones we were using were either not true or had some sag (either one possibly due to age).
The hairline scratches and the pad imprint were due to the polishing pad. Once we swapped over to a higher quality polishing pad (Pink Supreme or 549-7) the issue was resolved. I suspect this is due to thickness of the polishing pads as well as the nature of the felt (which determines how the polish particles are held). 

With the issue resolved, I'd like to give my thanks to those who gave their inputs and those who read my thread. Sorry about abandoning thread, hopefully this post will be a step towards making it up to you guys. 
Thanks again.

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