Lense Damage in Laser Cutter

A1) See #1⇑. Prevention is best addressed by contacting the manufacturer for recommendations; after all, a description of what is being cut and how it is being cut has been withheld from the forum.

A2) A discussion with the manufacturer will determine this.

<...Last November...> After all, one wouldn't want to do home-brew repairs on an item of equipment that is still under manufacturer's warranty.

It looks like you got something on the lens...the lens should be carefully checked before operation....I believe this is standard procedure....I would put a sign next to the "ON" button....and as a result you should have a way of quickly checking the lens that yields accurate results...You pay for your mistakes, get your money's worth...

As to your followup question, I expect the lens can be replaced at a much lower cost than replacing the whole system. Look at how easily you were able to remove the lens. Purchase a new OEM lens. Explore obtaining and mounting a protective, sacrificial barrier as Rixter suggested. Be prepared that you might find lens replacement costs are small enough compared to barrier and loss of production that replacing lenses might be the most cost-effective solution.

Looks like the barrier is the way to go. our quotes from Amada is north of $3K for the replacement lens, and we found an off brand that will sell us a lens for $2,700. Of course we have a spare, but we now need to purchase a replacement. Rixter help is the direction I think we're going to go.

by the way, we only cut mild steel. ASTM A1011 or ASTM A36

Redfred et al, pretty good comment... as far as getting to the cause and Preventive Maintenence,... you’ll need to begin asking question internally.

Now, when this happened, its unlikely that this happened over night,.. or the very last cut it made the previous shift, but it can happen,... (other possibilities, moisture, grease/oil on the material, etc... ), was there maintenence done recently?

Now, unless the operator was doing something not regularly done,... I’m not going to get into the unregular operations now.

but question the operator, and it has to be through, if he noticed issues when used last, and operations he did,... all the operations... also, if there was something that turn out he did something ‘unregular’, don’t be hard on him initial, or you’ll never get to the bottom of it in the future. But let the operator know.

I like to add, a 6000kW laser,... pretty nice size..

I’ve used a laser cutter. Frankly, I’m skeptical that such a small speck on the lens is the problem. More likely, it’s a symptom.

You didn’t mention any exhaust ducting system. It’s imperative using a laser cutter to use a high-speed, high-volume exhaust system to remove smoke and toxic gases that might occur when using a laser cutter. The smoke, by itself, scatters the laser energy and can greatly weaken the cutting ability of the laser.

The speck can possibly be removed without a major cost. Certainly the entire system needs to be thoroughly cleaned to remove all contaminants. Be sure that the output port of the laser itself is not contaminated with smoke or aerosol residues.

A plausible observation from the image presented. The circled opaque speck is quite small compared to the lens aperture. However, one cannot tell at all from the presented image if the surface areas around the speck are deformed or distorted, particularly in the infrared spectrum the cutting light energy resides. Furthermore, since the troubleshooting that found this lens defect succeeded in restoring production quality I believe you may have just introduced a red herring. Besides, the question was how this defect happened and how to prevent it.

I don’t see where the OP said they’ve already replaced the lens and restored production. Labguy said they’re ordering a replacement lens.

I agree that a barrier to protect the lens is a good idea, though I wonder why the laser cutter manufacturer didn’t include one or offer one. But the barrier itself may suffer damage shutting down production. A proper ventilation system should be Priority #1.

When we purchased the machine, we purchased a dust collector that is powerful enough to keep the cutting area clean and clear. when we replaced the lens with the back up, the poor cutting conditions went away, instantly. We are still trying to root cause the source of the contamination.

There is a possibility that nothing can absolutely prevent this from happening again. All of the possible systems to make this type of mishap as unlikely as possible have already been implemented by the engineers that designed this machine. You just had the misfortune of bad luck just a few months after installation.

On another note, I would be interested to see a near field image through the failed lens of some graph paper, screen or a repeated pattern. With the circle still around the speck for orientation. This might reveal a distortion of the lens surfaces.

You can see the glass stems are not perfect right angle cylinders from how they distort the circles in the background.

Would like to see a closeup at about 10x magnification...

You could try polishing it....

I had a similar experience. I have what seems to be a larger spec on a much smaller lens. I think it happened when I was aligning the mirrors., And a piece of tape I was using as a Target fell down into the lens aperture.

That said. The spec doesn't affect anything notably. Only when the lens gather's a fine sooty layer is performance compromised.

I find that it's best to pop the lens off before each use and give it a wipe with a Bausch & Lomb alcohol lens cleaner.

... Funny story I was at fabtech and saw a table full of amazing lenses for laser cutters. When I asked their sales reps about the coating on the lens and whether it was through and through.. they looked at me like a deer in headlights like I was asking the most technical question ever.

The lens is amazingly durable.

One time I was blasting Rock without the air assist and the lens became encrusted with rock debris that blasted up through the little hole laser shoots out of. Surprisingly it cleaned off.

Dear sir : I noticed in your question that you asked " how did this happen ".

Did your salesman forget to mention protective equipment and accessories ?

Sometimes sales will conveniently " forget " to tell the customer about needed supplies.

Maybe a complete inspection of your equipment is in order to tie up any other loose ends.

Hi Tony,

My salesman turned out to be a very typical salesman, and I thought I was old enough not to be taken in like a rookie, but I was. My lesson learned again was, although I've purchased many machine tools before, when I'm buying something I've never bought before, I truly don't know how much I don't know. As a result, my salesman has asked me not to contact him anymore and to call the service department with questions and issue. So, what happened to customer service after the sale??

So, the next question is, in response #2 it was suggested to use the filter to protect the lens. Does anyone have an Amada 3015, and do you use a protective filter on your machine?

I think you should implement the lens wipe before use suggestion and continue the investigation as to what the contaminate is and how it came to be on the lens...I would also install surveillance cameras pointed at the lens location from different angles...this would eliminate any tampering questions....Still would like to see a forensic analysis of the failed lens...

Laby, I checked on some prices for filter lenses, ( typical lenses ) and I see an average of $450.00 for a set of 10. While I have never used your type of machine, I can see that it would be prudent to include 2 + or more in a project order. It's like soap and paper towels = just the cost of doing business. I hope you can get what you need.

These cutters are repairable its not a big deal.

Implementation of lens may be helpful to burn it again.

.. I just remembered the targeting material that caused the damage.. oh well