(Lab) Machine related Issues (please read)

[SurferDude]

First time poster on this board,

And what do you know I have some machine related issues :)

Machines in Question
113 Generator
5056 Coburn Fining / Polish Machines

About two weeks ago I noticed that priscriptions with a high + or high CYL powers would come out with a very slight swirl in the edges of (poly lenses). These are not your typical deep swirl, you have to really take a good look at the lens for 2 / 3 minutes before you can detect them.

So I started with the very basics, change all my fining / polish pads. Replace the polish, ensure all steps are being done with blocking the lens etc. (No luck).

So take it a step more, Check the orbit / stroke pattern / all belts (make sure the lap tables are secure). Only noticed issues was a slight air leek from the actuator, however no play is given when a lap is on the table, Axis perfect / new pins ..... Still having the same issue. (At this point my actual LAPS are checked in perfect shape).

So a few days pass, and guess what (the problem is now affecting all lenses). What to do - what to do ... So back to basics check all lens powers / axis / prism .... etc everything is FLAWLESS.

Decide to work on the 113, I check everything from top to bottom curves perfect / belts excellent / tension / pressure / chuck / sweep speed ... Only possible problem ... My diamond wheel has not been changed in ages

At this point I have taken apart both machines and checked every aspect I can think of, and the problem still is around ...

If anyone has any ideas let me know,

Thanks a million :)

[Fezz]

First off, Welcome to the Board. Lots of good folks here. Hope you plan on jumping in on the conversations.

Now for your problem: Looks like you got most things covered. My first thought is to check temperature of your water and polish. I am sure others who are way more up on this than I, will chime in.


:cheers::cheers::cheers::cheers::cheers::cheers:

[gemstone]

Are you recirculating unfiltered water? Can you see the swirls before polishing? Also "knife edges" must be removed before surfacing lenses.

[braheem24]

Try surfacing your lenses about a 0.25 too steep so that they fine from the outer to inner part of the lens.

Let us know how it goes :cheers:

[HarryChiling]

Are you recirculating unfiltered water? Can you see the swirls before polishing? Also "knife edges" must be removed before surfacing lenses.

Ditto, tap water can be introducing contaminants from anything ranging from the pipes decaying to sand or grit. Always crib the lenses.

Now for your problem: Looks like you got most things covered. My first thought is to check temperature of your water and polish. I am sure others who are way more up on this than I, will chime in.


Also a great suggestion check the temperature of your water and the baum of your slurry. If the baum of the slurry is too low you will get these issues, I have found materials such as poly and spectralite are less forgiving than CR. Also I am sure you have doen this, but worth suggesting check the surface between each step, if it's fine after fining then chek your second step or polishing you may be able to reduce the problem to one machine and work from there. Good luck.

[OPTIDONN]

Try surfacing your lenses about a 0.25 too steep so that they fine from the outer to inner part of the lens.

Let us know how it goes :cheers:
Right. Check your processing sofware it may have an option to correct for elliptical error. Try and adjust the setting (often it will come out with a .25 difference like braheem mentioned). Had the same problem.

[gemstone]

Right. Check your processing sofware it may have an option to correct for elliptical error. Try and adjust the setting (often it will come out with a .25 difference like braheem mentioned). Had the same problem.
Elliptical error is on the cylinder only. The more cylinder,the more the correction. If your software does not have a correction, you may be able to get a chart from Gerber Coburn. I used to keep one posted at the generator.

[OPTIDONN]

Exactly and this should nearly eliminate the swirls from the high cyls. as for the high plus lenses what size block are you using?

[gemstone]

Where it STARTED later on "all lenses"

[DragonLensmanWV]

Right. Check your processing sofware it may have an option to correct for elliptical error. Try and adjust the setting (often it will come out with a .25 difference like braheem mentioned). Had the same problem.

Watch out for setting the curves too steep, some lens materials will flex too much at the edges of thin plus lenses, creating a lip on the back surface of the lenses.

[OPTIDONN]

Where it STARTED later on "all lenses"

OK? Still a good idea to check elliptical error.

[OPTIDONN]

Watch out for setting the curves too steep, some lens materials will flex too much at the edges of thin plus lenses, creating a lip on the back surface of the lenses.

That was my next thought. If you said the wheel has not been changed in ages the lens could be flexing when it should be cutting.

[MTAMERIUS]

have you tried fining water additive? it will help keep lens swarf from building on your pads. the other thing is material stock removal. are you seeing any big changes? do you do a mix of materials in the same fining water?

[Chris Ryser]

One old timers suggestion...............might work.

Reduce pressure ! .............................and find out.

[SurferDude]

Wow, did not think I would get so many replies (thanks!!!!)

This is what I did today ...

Ran a few tests lens, first off I ran a CR39 test lens 625 / 625 (6 base) and put it in the 113, the first thing I noticed is that the edges are not being brought down equally, so I tried the test lens a few more times and thought that the sweep speed may be a bit to fast, so I played with the sweep for a few attempts, but no luck , at this point im thinking that the 113 diamond wheel is seriously affected ... I doubled checked all grease fittings / made sure the oil levels were topped up. The sag for the test lens was perfect, (curves are super)

Ok so next, the water is not recirculated, and temps are perfect (i doubled checked the polish temp / made sure my chilling unit was running good). all was perfect.

I received my two lap tables for the 5056 today as I mentioned the baffles / actuator were leaking. when taking apart the fining tables the first thing i noticed off the bat was the actual unit was "stuck on hard" when I finally was able to take off both lap tables, I noticed "rust" in the lower lap table areas, so i put a little extra grease on both tables, I again checked all orbits / stroke patters / axis etc. ...

Now, I was able to get 2 lenses out ... CR39 / orange first 2 minutes !! / green step 2.5 minutes finally polish 6 minutes, pressure was set at 17psi all around. This was the first lens I was able to get with none of the evil swirls in a while.

I then put a polycarb lens with a high cyl / (progressive) / high prism .... Off the bat the problem came up again, I ran the lens extra / extra / extra and was finally able to get the swirls out ( before I couldn't at all.)

At this point im thinking it must be coming from the 113, but I could be wrong, I placed an order for new belts for the 5056, just as a precaution.

If anyone can think of any ideas let me know, im trying to eliminate any possible issues, jesus i went as far as changing my damn block centers :)

thank you

[gemstone]

Look for spots of poly on the pads after surfacing. Swirls are usually almost always caused on finers or polishers. The 113 we had (HW) automatically had elliptical correction. You are probably getting little spots of poly build up on the fining pads. If you look at the location of the swirls and the pad on the tool you can probably find the build up spots. Another reason to have a routine for putting the tools and lenses facing the same way, so you can find these things. If you have established it is off the finers, before polishing. You should filter the finning water and use a finning additive (as someone mentioned before.) Make sure you are using poly fining pads. Sounds like you are removing plenty of stock with those times.

[DragonLensmanWV]

Look for spots of poly on the pads after surfacing. Swirls are usually almost always caused on finers or polishers. The 113 we had (HW) automatically had elliptical correction. You are probably getting little spots of poly build up on the fining pads. If you look at the location of the swirls and the pad on the tool you can probably find the build up spots. Another reason to have a routine for putting the tools and lenses facing the same way, so you can find these things. If you have established it is off the finers, before polishing. You should filter the finning water and use a finning additive (as someone mentioned before.) Make sure you are using poly fining pads. Sounds like you are removing plenty of stock with those times.

Yes, It does sound now like it might be your pads. I never ran poly here but even though I can get second fine pads cheaper than the 3M blue, I still stick to them. Try some different second fine pads, maybe a slightly less aggressive first fine too.

[braheem24]

Check the diamond alignment.

If you still cant figure it out, get another lab to surface a pair of lenses and you fine and polis them if there are no swirls, you know it's your 113, if there are swirls it's your cyl machines. :cheers:

[Lab Guy]

One thing you may need to check is your pressure regulator, they usually read a little lower than the actual pressure,unless you have any kind of air leak in which case the pressure may fluctuate up or down.Also, if the lens clamps are old they may misbehave as well.