Hi Folks,
our laser tube was replaced in 2012. The machine is a ULS M-300, (45 watt) and it hadn't done much work after it was renewed.

It was going fine for me after we bought it, last year, but the last two jobs I've done have been an incredible struggle to cut through 3mm acrylic that it normally sails through. I've had to drop the speed down to about 1.5 % and power at 100%. If the speed was 2.5 to 3%, it would not go right through.

If I set it to cut out say 8 acrylic elements, it'll do the first 2 or three OK, then cut less and less as the job progresses. I've had to break cutting down into say 2 pieces at a time instead, and send them, to stop it from running out of grunt partway through a bigger job.

I have double-checked and cleaned the lenses, and I've checked the focus at 2".

Is this a sign the tube probably needs regassing, perhaps, or might there be some simpler fix I have overlooked?

Thanks in advance for any suggestions!