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Chang Chou Optical Technology
Lens Processing
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@ Finishing Procedure

Edging

1. Polycarbonate lens can edged using present CR-39
procedure with slight modifications using a dual propose
CR-39/Poly Wheel.
2. Use the dry edging for polycarbonate lenses. coolant
should be turned off until the last one or two cycles.
This will makes the lens edge brighter.
3. Clean the edge machine regularly, If there are chips
sticking on the diamond wheel, clean them with oil stone
or sharp pick.
4. Adding a filter at the end of water pipe from the edge
machine to filter the edging chips.
5. Take down the bigger chips carefully from the lens edge
when they are found during the edging process to smooth
the edging work.

Pin Beveling

1. A standard ceramic wheel may be used. Dry beveling is preferable as wet tends to load wheel and is slow.
2. If chips are found at the edge of the lens, use single edged razor blade to remove. Be carefully not to damaging the lens.

Grooving

1. Use standard CR-39 grovving machines dry.
2. If chips remains in groove, use a pick or single edged razor blade to remove.

Drilling

1. General drilling machine can be used. However, use sharp drill is important. A dull drill will melt the material plus add stress to the lens. Adjust speed of drill to approximately 160-180 RPM.
2. Clean the chip in the drilling hole by a tooth pick or tiny stick.

Polishing Edges

1. Use standard CR-39 techniques with a buffing wheel and polishing compound. But, use softer and delicate polishing cloth. green oil polishing earth is recommended.
2. Use slow speed on buffing wheel and less pressure than CR-39 to minimize stock removal and heat build-up.

Glazing

1. The rule to keep in mind when glazing PC Lenses is to eliminate stress to the lens from improper sizing. mountingor excess tightening of screws, stress will eventually lead to the crazing or cracking of the lens usually days or weeks after dispensing.
2. The crazing or cracking will usually appear and localized fine hailines radiating inward from the overly stressed area of the edge of the lens or from an overly tightened screw mout. Occasionally, if the lens is evenly oversized, the equal stress will result in the center of the lens cracking.
3. Inspect mounted lenses using a polariscope.Excessively stressed areas will appear as bright colors. usually purple and yellow. hand edge or loosen the screw until the stress is removed.
4. With screw mounts, use inserts or washers where polible.

@ Trouble Shooting

Problem A: Edging melting or cracking at edging

Problem B: Lens bending in frame or cracked after worn a period of time

Cause

1a. Excessive heat build up



2a. Diamon wheel too fine




3a. Cutter tips dull on router type

4a. Diamond wheel loaded with polycarbonate material

1b.Lens mounted too tight







2b. Rimless screw mount too tight

Solution

1a. Turn coolant off. Coolant slow the cutting action, resulting in heat build up

2a. Use a coarse diamond wheel recommendeded for Pc by the edger manufactreer

3a. Replace Cutter


4a. Clean wheel


1b. Check lens in polariscope after mounting to determine excessive stress points. If stress exists, remove lens and hand edge stress areas until no stress is present when viewed in polariscop

2b. use sharp drill and bushing for screw mount. view in polariscop to avoid over tightening

Please contact with sales manager Mr. Chen Tony
TEL: 886-6-2547818
FAX: 886-6-2549943
Mobile: 886-939986075

e-mail: cchingoo@hotmail.com

Copyright 2001 Chang Chou Optical Technology CO., LTD. All Rights Reserved Any unauthorized use or duplication of the contents or graphics on this page is strictly prohibited under penalty of law.