Problems encountered in cleaning OMTech 80W

Assuming you’re running the same jobs, then a sudden change suggests a hardware problem, rather than the gradual deterioration brought on by crud accumulating on mirrors / lenses.

Check for a loose mirror or focus lens: the lock rings must be snug.

If the machine has molybdenum mirrors (heavy metal slugs), then they’re easy to clean. If it has gold-plated silicon mirrors, then they’re easy to damage; check for any surface imperfections.

Similarly, the focus lens must be clean. You must dismantle the laser head to get to it, but make sure it is both clean and undamaged. Assemble with the convex side upward, remember the silicone washer, and snug the lock ring against the lens.

If the tube produces a good TEM00 spot when it’s cutting well and a bad spot (ring / blotch / whatever) when it’s not cutting well, then the tube is going bad. It seems they can flicker between “working OK” and “yuch” without anything else changing.

However, if the machine stopped cutting well and did not recover after cleaning and the test spot looks bad, then the tube has definitely failed.

As a rule, I keep the machine clean of material residues and dirt continuously, primarily to minimize the fire hazard.
Regarding the lenses, in my opinion, it depends a lot on how effective your extraction is. If there is always compressed air on the nozzle and the smoke from the laser process is led out of the cabin effectively, then the mirrors and lens will not get dirty for a long time.
I use a flashlight to check the M2, if it gets dirty, the whole system gets a turn. But months go by between cleaning the mirrors and lens when I process “normal” materials. However, some materials produce more dirt than others, so the cleaning interval must be adjusted, but I’m still talking about weeks between cleanings.
Have you checked your alignment recently? It could be that it no longer fits. Also check if the lens is tight in the nozzle and is not broken.

I’ve only had my 130w for a month, but have been cutting acrylic and wood…
I just changed my lens from 3" to 2" for testing and decided to clean the 3" lens since I had it out…
To my surprize there was a pretty good haze on the top open side, this is from cutting birchwood the last week…
So lessons learned, they seem to get dirty pretty quick…
Clean weekly, or maybe more often depending on your air flow and how much you cut…