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View Full Version : New Lens, getting hot and smoking... ideas?



Amy Shelton
07-22-2014, 10:14 AM
Edit: Clarification... the subject should be getting hot and sooty. There isn't any smoke present.

I purchased a new 2.0 lens from ULS. It was engraving perfectly! I was engraving some stainless using Thermark tape. Then as time went on, it wasn't doing as well on the edges (where they fade out of focus). I decided to check the lens, and found the carriage area to be hot. The lens was blackened with soot that was easy to clean off.

I'm not using a nose cone, and not using air assist (but I am using the exhaust fan).

I did a beam alignment with both the red dot and the laser, and it's burning in the same spot in all four corners.

I cleaned the beam window optics, and there's a minor scratch there. The mirrors are fine.

This lens has a purple cast to it, when I hold it with a light shining on it. My original lens (2008) has a green cast. I don't know if that makes a difference.

It looks the same otherwise. I have been using the same original lens since July 2008. The only reason I needed a new one was--- I did a dumb thing -- I was engraving (not cutting) wood and it was getting smoky. So I turned on the air without the cone, thinking it would help clear the smoke. Later, I read here that it can cause problems, and it sure did. I got some debris on my lens that won't come off.

If you have any suggestions to try, I'd appreciate it! I tried to find a similar problem here and couldn't find one.
Is the minor scratch on the beam window enough to smoke up the lens?

Thanks in advance,
Amy

Bert Kemp
07-22-2014, 12:39 PM
Well I think the lens is getting hot and smoking from the soot you said you got on it.
Is there a reason you don't use the cone and air assist all the time?
The cone and air will help blow all that soot away from the lens keeping it clean and should help keep it cooler also. I have never run the laser with out both on and working.

Amy Shelton
07-22-2014, 12:52 PM
Hi Bert, thanks for your reply.

I meant to say the lens is getting "smoked up", not that there's smoke coming out of it.

I don't know what is causing the soot, or debris, on the lens.

I can't use the cone on it since it's a curved object and I have to focus a little closer to be able to have the logo engraved to the edges.

It's rastering, using Thermark tape. I have done thousands of these pieces over the last three years or so.

I am trying to determine if my new lens is to blame, or is something else going on?

Bert Kemp
07-22-2014, 6:03 PM
How much of a curve does the object have. I find that most curved objects engrave just fine focusing at the top of the curve but even if you split the differnce you should still have room for the cone to go on.

Amy Shelton
07-24-2014, 10:03 AM
Got it! We figured it could be the exhaust. The smoke is evacuating just fine, but maybe that was it. We took the dust collector apart and cleaned it up well, cleaned the exhaust plenum in the laser, and most of the duct work. The ducts that we didn't remove could be inspected visually from inside the laser.

It made a HUGE difference. Lens is clear after engraving 20+, whereas before, it would start getting the smoky residue after just 3 parts.

Bert, the cone does barely fit, but it's too close for my comfort. I'll keep checking it, and will use the cone & air if it continues to be a problem. But I'm hopeful it's fixed!

***
So, the moral of the story is:

Clean your external exhaust fan!!! Lol Even if it seems to be blowing well.

Bert Kemp
07-24-2014, 10:32 AM
Got it! We figured it could be the exhaust. The smoke is evacuating just fine, but maybe that was it. We took the dust collector apart and cleaned it up well, cleaned the exhaust plenum in the laser, and most of the duct work. The ducts that we didn't remove could be inspected visually from inside the laser.

It made a HUGE difference. Lens is clear after engraving 20+, whereas before, it would start getting the smoky residue after just 3 parts.

Bert, the cone does barely fit, but it's too close for my comfort. I'll keep checking it, and will use the cone & air if it continues to be a problem. But I'm hopeful it's fixed!

***
So, the moral of the story is:

Clean your external exhaust fan!!! Lol Even if it seems to be blowing well.:DGlad you got that fixed:)