FreeForm Engraving Cr39

Hello,

I have a trouble with the engraving. I use a VFT Compact (Satisloh) and i use a mechanical tool for engrave.
I have a trouble when i hardcoated the Cr39 (and only the Cr39 because with the organic 1.6 the result is good)
I have a dipping machine (SCL CD200) and I use a vanish 1.52 (for CR39 and 1.6)
So when I hardcoated cr39 , the result is bad. I have a vanish point in the engraving. I test different hardcoated thikness and different depth engraving.
It's strange because the 1.6 the result is good. The result is good with different thickness and depth.

Do you have a idea?

Thanks for all and I sorry for this text. My english is very bad

What happens if you take a CR39 engraved lens and dip it in the 1.6 varnish? If it is still the same then it may be the engraving side.
If it is good, then I would say your varnish may be at fault. Perhaps the solids is too low, or the temperature of the varnish is an issue.

Etienne, please explain to me how you can engrave after dip hard coat, when the lens is obviously already off the manufacturing block and thus the true position/orientation of the lens surface is lost?

Have you ever tried to engrave the lens material rigth after surfacing and then coat over ? This seems to be the more usual way...

Georg Mayer

Better Best then Biggest

PS your English is better then my French

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Originally Posted by Georg Mayer

Etienne, please explain to me how you can engrave after dip hard coat, when the lens is obviously already off the manufacturing block and thus the true position/orientation of the lens surface is lost?

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Georg, my explanation was not so good. I engraving the surfuce just after the generation (and before the polish (look the link)). So the lens are already engrave before the hardcoat.

I think i have find. After many test and a very good technical support (SCL Compagny Jean Gehrig), the trouble is "tension of surface". The tension are during engraving. The surface is stressed
For dicrease this phenomenom, i increase the chemical attack.

Do you have a product for dicrease this trouble?

Tkanks for your help

Hi etienne
Anyway you can slow down the engraving, which may help relieve the surface stress? Or have you tried to increase/decrease this speed to see what happens?
I would think that if it is being done in the VFT, then the polishing porcess would smooth out the engraving. Is it cutting in too much?
Have you looked at laser engraving?

Just thinking of what else you can try to get to the bottom of the issue.

Good Luck.

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Originally Posted by IC-UC

Hi etienne

Have you looked at laser engraving?

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Unfortunately, i dont choose the machine. My boss said that a laser engraving is more expensive. Me, I dont know.

I go to test the engraving CR39 with an other cut speed. But now, the result is good with a good chemical attack

Is the tool used for engraving you mentioned a manually operated device? If so where can one buy this from?

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Originally Posted by lens_man

Is the tool used for engraving you mentioned a manually operated device? If so where can one buy this from?

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No, mechanical tool for engravings is part of VFT Compact generator (Satisloh)

Meanwhile, i found one external mechanical engraving machine - OME-80 (Optotech)

I have heard this same problem when engraving with the VFT ,and the best solution is to use a laser engraver,this is what we use in our Lab.I've also seen the external mechanical engraver from Optotech which works well and less expensive.But laser engravinng is far the best solution.

Hi! Do you still have Optotech engraver.? Send me and email albertzcampos@outlook.com

Hi! Do you still have Optotech engraver.? Send me and email albertzcampos@outlook.com