Help with Poly Surfacing

**Hoss** · 01-26-2011, 08:31 PM

Hello all, I was hoping for my first post someone could shoot me some advice or any thoughts and suggestions.

I'm a Lab Manager for a mid volume full service lab. We recently starting surfacing poly. I'm having some issues with swirl marks on a small handful of jobs. Its completely random and happens on about twenty percent of my poly surface.

I run a 2G generator with a new blade and motor. A set of 505 cylinder machines for fining and polishing. I'm running a two minute 1st fine cycle and a two minute second fine(17lbs of pressure). I'm using DAC velocity one step pads but the swirls are horrible if I don't two step. I'm running a six minute polish cycle(18 lbs of pressure). My water and polish are chilled to about 65 degrees. I'm using Americal Plus polish.

I have been troubleshooting this for several months but I just can't get it as consistent as my cr39. If this is as good as it gets I can live with it but I'd like to get rid of them completely. Is that possible? Or is this just the nature of the game with poly?

Sorry for the long post.

P.S
I know the 505's are really designed for glass and plastic. Replacing them or my generator is not an option.

Thanks for any help. If any other info would be helpful just let me know.

**fjpod** · 01-26-2011, 10:01 PM

Many folks, myself included, cannot do one step poly fining either. In my case, my older generator leaves a dimple in the center of the lens and we have to fine with a rougher pad for a longer time, and second fine. We are using PSI 2 step poly pads. I forget the number, but the first fine is black, and second fine is brown.

**Hoss** · 01-26-2011, 10:41 PM

Originally Posted by fjpod

Many folks, myself included, cannot do one step poly fining either. In my case, my older generator leaves a dimple in the center of the lens and we have to fine with a rougher pad for a longer time, and second fine. We are using PSI 2 step poly pads. I forget the number, but the first fine is black, and second fine is brown.

I used to have some of those laying around, I've since gotten rid of them. But now I'm curious because the one step pads I have aren't near as rough as those were. Maybe I need a more aggressive first fine? Interesting....

Thanks for the response.

I almost think my swirls are not getting polished out. What polish pad are you using?

Also, I hate to be a pain but....
What times are you running for each?

**fjpod** · 01-27-2011, 04:43 AM

I use the PSI yellow polish pads for 5 or maybe 6 minutes on poly. My first fine is 4-5 minutes, depending on the severity of the curves and thickness of the lens. Second fine is 2 minutes.

These times may seem ridiculously long to some, but I am limited by the dimple I get at the center of a poly lens. C'est la vie.

**eyemanflying** · 01-27-2011, 06:22 AM

With a high breakage rate, horrible optics, high chromatic abberation, extra labour/processing time, wear and tear, short life span, low margins, coating adhesion issues, dispensers cracking them with acetone and only your cheapest customers demand it, why bother selling it?

Here's my suggestions...

1. Do a 180 turn on the decision to offer poly. Or...

2. Farm out the poly surfacing to another lab and edge it only. Then at least you've improved your breakage by 20%. Or...

3. Bring your 1.6 pricing feasibly down as close to poly pricing as possible - then give an incentive...increase their warranty if they jump up to the 1.6.

**WFruit** · 01-27-2011, 09:35 AM

1st fine should be about 2 minutes with a course pad (we use a black) and 2nd fine should be about 2 minutes with a finer grit pad (we use a brown). Polish should be 5~6 minutes (we use the yellow pad, but I've seen pink as well). I would put the preasure for each at 18~20. Polish should be chilled to ~50 degrees, although that will do more to reduce heat related issues such as waves. Also make sure that you are filtering the polish and the water to remove debris.

I know you said you can't replace your finers/polishers, but I strongly recommend keeping an eye out for a good deal on some 5056 cylinder machines. Yes, they're an old model, but they run FOREVER and they are really easy to maintain and repair when needed.

**Hoss** · 01-27-2011, 10:13 AM

I have heard that we may be offering something like a 1.6 in the future as well as the poly. I only average about half a dozen poly surface a day, some weeks are better than others. I can go for days sometimes with no issues then boom, two or three in a row.

Thanks for the responses.

**DragonLensmanWV** · 01-27-2011, 03:35 PM

Try cutting a sphere test lens, then cover up the back of the lens with a Sharpie, and fine for 10 seconds. Examine where the Sharpie has worn off. If it's just worn off in the center, your curves are a bit too flat so you steepen them just a hair and repeat until your 10 second fine wears off the markings around the edge, say a 15 mm clear band. This prevents you from fining from the center out, which is OK for a lot of materials, but a no-no for poly.

**Wes** · 01-27-2011, 08:46 PM

No one's mentioned this yet, but have you checked the generator settings? I've seen some 2Gs setup incorrectly and the swirls get very wide and pronounced. You can set the machine up to give a better finish, but it takes longer to process.

**Matteomix** · 01-31-2011, 03:06 AM

Recalibrate the 505s, I'm sure you've done that already. I usually run 1.5 minutes on first fine, 1.5 on a second fine with an orange fine grit pad. 4 minute polish with 5056s

**Freebird** · 01-31-2011, 08:38 AM

When we have swirl marks in our poly lenses, it is usually due to the lab tech not having the pad adhered smoothly onto the lap tool. If there is a ripple or a crease in the fining pad, either first or second (we use DAC 2-step (blue and orange) fining pads and DAC blue polishing pads and polish), we usually end up with deep swirl marks. Our typical solution is to polish them for an additional minute or so (we run 2 minutes on both first and second fine, and 5 minutes on polish).

Now, if the swirl marks are the cutter marks left by the generator, it means in my lab that the curves on my 2G are either way too steep or too shallow. If you don't have a sagometer and sag charts for your lap tools, cutting a lens and coloring the backside with a sharpie or china marker and then fining it for about 10 seconds will give you the same idea. If it fines out from the edges but leaves the middle untouched, the curve bias is too steep. If it fines out from the center and leaves the edges untouched, the curve bias is too shallow. Ideally, after 10 seconds of fining, any marker should have fined out completely.

**hipoptical** · 02-04-2011, 11:17 AM

The best advice here came from eyemanflying. Ignore everything else. It's the only sensible thing to do.
(Not a poly fan AT ALL. It's a terrible, horrible, no-good, very bad material.)

**partyoptician** · 02-08-2011, 11:12 PM

Hoss, I to use to run the 505's for poly and was just never able to run one step pads, it just doesn't work. Go back to two step and you will be fine. the money you are trying to save is being eaten up with your breakage.

**DragonLensmanWV** · 02-09-2011, 07:15 AM

Originally Posted by hipoptical

The best advice here came from eyemanflying. Ignore everything else. It's the only sensible thing to do.
(Not a poly fan AT ALL. It's a terrible, horrible, no-good, very bad material.)

Even in Australia?

**hipoptical** · 02-09-2011, 06:06 PM

Australia...? Why would poly be any different in Australia?

**fjpod** · 02-10-2011, 05:09 AM

In the southern hemisphere, motors turn counter clockwise...and everybody knows poly doesn't grind right if the motor goes counter clockwise. (don't listen to me.)

**DragonLensmanWV** · 02-10-2011, 07:15 AM

Originally Posted by hipoptical

Australia...? Why would poly be any different in Australia?

You must not have a kid who once read "Alexander and the Terrible, Horrible, No Good Very Bad Day" where Australia was mentioned.:bbg:

**Mike Fretto** · 02-10-2011, 10:33 AM

You said your water is chilled Im assuming your running some kind of filtered tank. If so is the filter and water changed frequently, are the swirls consistent or occasional, any particular spot on the lens, center or edge. There have been many good suggestions about looking at the curves off your gen. We run an SGX with an 11 flute cutter Max DOC is 3.00 Feed at DOC is 225.0 Final DOC also 3.00 Fine @18 lbs with one step Black Knight for 2.30 min. Polish @ 18 lbs with Ultra Polish pads for 4.00 min. using Premium lens polish all by DAC. No swirls at all and we probably do around 100 lenses per week

**hipoptical** · 02-10-2011, 01:35 PM

Originally Posted by DragonLensmanWV

You must not have a kid who once read "Alexander and the Terrible, Horrible, No Good Very Bad Day" where Australia was mentioned.:bbg:

I read it as a kid, but haven't seen it since 19... well, since I was a kid, and I don't remember Australia. (I loved that book, I should get it for my kids.)

Back to the problem solving...
I used to process very similarly to Mike Fretto and had the same results. We used exactly what our local DAC rep suggested and rarely had issues. We processed around 250 pair per week. Try switching to the Black Knight and get a better (or different) polish. I like the 11 flute cutter, but also had success with the standard 3 flute for poly.

**Mike Fretto** · 02-10-2011, 02:59 PM

The only down side to our setup is cribbing takes forever. As little work as we do it isnt really an issue as far as time. Crib Reduction is 25 and feed is 200 any more or faster and they seem to come off the one step wax block. Curious to get an answer on the water issue hadnt seen that asked yet. We have to run a small filter system in the summer with a chiller, the city water here gets way to warn to run direct.