Engraving on Lenses - CR39 material

[Khalid Nazim]

Following up on my post earlier, I got lenses from my customer and he wants me to engrave a small logo on a corner on the lens - see picture below. I tried to do it on the sample lens that he gave and got mixed results - probably due to the curvature of the lens. I have couple of issues that I need help on:

What do I do to ensure consistent engraving on the curved surface of the lens?
What setup/holding arrangement should I have to ensure that I can engrave 100 of these lenses consistently?

The customer will give the lenses only and not the frames. Would it help if I get the lens in the frame?

If I can crack this issue then I can have consistent orders from this customer.

Thanks
Regards
229418

[Joe Hillmann]

Since the area you are engraving is so small I doubt the curve would be much of an issue. I would build a jig that only holds the area that is being engraved as level as possible and not worry about the rest of the lens. Then when you do the focus, focus between the high point and the low point of the area to be engraved and use the longest focal length lens yo have. If that doesn't work then I think that the problem is in the color difference in the materiel. If that is the case they you could play with half tone images to get even engraving or just use the laser to cut stencils and then sandblast the lenses.


Also if the lenses are polarized they might react differently depending on if they are engraved on an x or y axis.

[Glen Monaghan]

I'd rather get just the lens as it would be much easier to set up a small jig for that. As Joe said, position the lens so the corner you want to etch is as level as possible. I'd bet the lenses don't have enough curve there to make much difference but I'd measure the high and low points and try to set the focus midway.

You say you got "mixed results" but the picture is too small and blurry to actually see what you got. Better description/picture of the problem???

(I think it would drive me nuts to have that engraving there at the top of my FOV... why not put it on the frame?)

-Glen

[Khalid Nazim]

Thanks for suggestions. I will try with longer focal lens. The image I attached is the customer rendering of how and where they want it on the lens. I will post my results as soon as I am done with some more tests.

[Dan Hintz]

Since the area you are engraving is so small I doubt the curve would be much of an issue.
Correct.

I would build a jig that only holds the area that is being engraved as level as possible and not worry about the rest of the lens. Then when you do the focus, focus between the high point and the low point of the area to be engraved and use the longest focal length lens yo have.
That's what I would do...

Also if the lenses are polarized they might react differently depending on if they are engraved on an x or y axis.
Polarization coatings would have no effect on surface engravings...

[Mike Null]

The jig/fixture is the correct approach and a 2" lens should do the job perfectly. Don't bother with the frames.