Lens issue

[Albert Nix]

Has anyone had the coating on a lens start to peel of starting from the outer edge. I have always taken good care of my lens's and its less than 18 months old. The center of the lens is still good but the spot that is peeling is slowly growing. Has anyone ran into this before.

[Dan Hintz]

That's typically the result of moisture incursion...

[onur cakir]

I've been worrying about the same thing for a while...

How to prevent that incursion ?

[Dan Hintz]

Peeling to that degree says it was (most likely) a drop of water (not just vapor)... if the optics box is pressurized, like on ULS machines, suspect water in the air lines.

[Dave Garcia]

Dan,

Would you suggest that a dryer/filter of some kind be placed in the air supply line before the laser head if one does not have a pressurized unit?

Dave Garcia
The Wood Block, Ltd

[Albert Nix]

Water could be a possibility. On real humid days I have noticed a few drops around the valve outside the cabinet where you regulate the air flow. I ask the tech folks when I first noticed it and they said that it should not be a problem. Anyway I noticed it again the other day and so I moved the little compressor into the office (air Conditioned)where the machine is and I havent seen anymore water. Hopefuly the a/c is acting like a dehumitifier but I may still need to add a filter. I wounder if there is a way to seal the edge where it is peeling?

[James Jaragosky]

I have some peeling as well, and I do not have air assist.
My lens has been in use for two years.
It was supplied with my Chinese machine.
I am thinking it may be from heat building up, due to my lack of frequent cleaning. This is just a guess on my part.

[Rob Bosworth]

The coatings used on coated optics for a CO2 laser are hygroscopic, which means they will absorb moisture. So any moisture or oils that come into contact with your coating will be absorbed. When a CO2 laser beam passes through the optics, the moisture will absorb some of the laser energy. This absorbed energy turns to heat. Between the heat and the moisture helps break down the bond of the coating to the optic substrate. You eventually will see flakes of coating coming off, or if the optic absorbs too much moisture and energy, they will actually fracture. Higher powered systems are less forgiving than lower powered systems.

That is why most laser systems manufactures offer warranties on their machines, but do not cover consumables, usually meaning optics.