Hand Edging Special Considerations

Question 1

What are the 4 reasons to hand edge?

Answer 1

-Smooth edge surfaces
-Remove sharp edges from a lens after it has been machine edged
-Reduce lens size
-Reshape

Question 2

How do you remove chips using a hand edger?

Answer 2

steepen the rear bevel angle in the area of the chip to grind away chips

Question 3

How do you salvage an off-axis lens with a hand edger?

Answer 3

modification of the lens shape-especially lenses with distinct corners to not disturb appearance of frame

Question 4

How do you correct for unwanted vertical prism using a hand edger?

Answer 4

Removal of extra lens material above from top or bottom of
lens to move MRP relative to frame

Question 5

What are the different ways a lens edge can be polished? 4

Answer 5

-In-edger polishing
-Rag Wheel
-Drum Tool
-Polishing Machine

Question 6

Explain in-edger polishing. 2

Answer 6

-A wheel inside an edging machine which has the ability to give lens edges a high luster
-Amount of polish can vary depending on age of the wheel

Question 7

Explain a Rag wheel for polishing edges.

Answer 7

Lens edge is buffed by hand on a rag wheel using buffing compound

Question 8

Explain a drum tool used for polishing edges.

Answer 8

-Lens edge is buffed by hand using a flat rotating drum tool with a felt surface where buffing compound is applied

Question 9

Explain a polishing machine. 2

Answer 9

-An automatic machine where lenses are placed after edging
-Lenses are not deblocked before using this machine

Question 10

What 4 considerations need to be made when re-edging for a different frame?

Answer 10

-Distance between optical centers needs to remain the same
-Lenses must be large enough
-Rotating the old lens so it fits the new frame may not work
-Glass lenses need to be re-hardened

Question 11

What should we consider when cleaning glass lenses? 3

Answer 11

-Non-water-soluble markings can be removed with a solvent or alcohol
-Detergent or lens cleaner can be used
-Small spots can be removed using the point of a lead pencil

Question 12

What should we consider when cleaning plastic lenses? 3

Answer 12

-Acetone can be used but should not
contact plastic frame parts
-Detergent or lens cleaner can be used
-Ultrasonic bath can be used but not on lenses with antireflective coatings

Question 13

What should we consider when cleaning polycarbonate lenses? 3

Answer 13

-Mild, non-citrus based dishwashing detergent is recommended
-alcohols will work but are considered a secondary option
-Do NOT use methylene chloride, methyl ethyl ketone or any
of the ketone family, acetone, or chlorinated/aromatic hydrocarbons

Question 14

What are the basic rules for hand edging?

Answer 14

-keep the angle between the hand edger and the lens consistent
-listen to the wheel
-travel as far around the bevel as possible without lifting the lens away

Question 15

Explain how to make the most of the blemished sphere lens blank. 2

Answer 15

-same power can be rotated around the OC
-same power all over the lens

Question 16

Explain how to make the most of the blemished spherocylindrical lens blank. 4

Answer 16

-two major meridian
-two possible orientations
-can be flipped upside down to work 90=270, 0=180
-process is done after spotting and before R/L is marked