Naked Blanks

[PNKansas]

Lately We Have Been Running Into A Problem Getting Naked (uncoated Cr-39 & Trivex) Products Through Our Wash-up Area Into Our Ar Facility Without Scratching The Blank. Does Anyone Have Any Ideas That They Would Like To Share On The Process That They Have Successfully Been Through??

Any Thoughts Or Ideas Would Be Appreciated.

Thanks

[Del]

what kind of scratches are on the lenses?

Are we talking scratches from clipping the lenses into the pannier, handling scratches or circular scratches due to maybe contaminated deblocking rings? if of course you are a production facility.

Need some more information.

[PNKansas]

Yes we are a >500 jobs / day production lab. I am looking for suggestions or other ideas of some wash-up procedures that we can try out to see if we are missing something that we could be doing better. I wont tell anyone that some could be from mis-handling which is to be controlled. However for the most part I am looking to see what other labs or people have done in the past that has worked for them.

thanks

[PNKansas]

Not to make this any longer, but to answer your question the scratches are random and the majority that are being found are all on the - side of the lens instead of the front side.

thanks again

[Websta]

There could be many reasons for your troubles. Fining times and pad combinations, Polishing pads and times, deblocking procedures.
Try checking some lenses after evry stage of the cycle and see if you notice an issue.

From what you have described the problem can occur at any one stage of the process, so you will have to take it step by step.
With more information it will be easier to trouble shoot.

Good luck.

[renee1111]

When we take the blank out of the box we first check it for scratches then immediately tape it (clear tape) before it's sent to surfacing. We use freebond in surfacing, which, if your manufacturing 500 jobs a day, I figure you are too. We don't even use the deblocker anymore, because of scratches, so we deblock by hand. Lastly we use an air blower to dry lenses once they come out of surfacing (not kleenex). All these steps seem to help quite a bit, since we hardly ever get scratches anymore.

Another thing we have done is stopped ordering uncoated lenses all together, specially for Trivex. Since the only reason we used to get uncoated, would be for AR coatings, but realized the coating company can strip it off anyway. You'll pay a bit more for coated lenses, but save on scratches (and your bottom line) in the long run.:o Hope this helps..

[Websta]

Hi,

From what you have said, it seems that the scratches are on the - side, so the issue does not lie with the blank quality. I would investigate the polishing compound (viscosity, baume reading, filters etc.) first.
Another area to look at is the deblocking process. It may be worth your while looking into the washing processs as the cloth they are using, or the water may have contaminants (bits of tape, metal, build up of hard polish etc) which may cause the problems.

Do you notice that it perhaps happens at the start of the day? Could be due to lenses sitting with dried polish on them.

Good luck, hope you find the problem.
Cheers