OK, so I recently dialed in my Shenhui which included lowering the tube slightly to get better alignment, mirror replacement on 2 of 3 mirrors (new Mo mirrors) and a fresh lense (which I've since toasted due to soot - but that was an air cleaning issue). Cuts finally were as good as I had hoped for 2 years ago (I had sort of powered through or worked around issues until then). I have a 150w Reci and I typically cut acrylic at 95% power as fast as I can get away with. Right after dialing it in, I got 6mm at 20mm/s in the far bottom corner of the 1200x900 table which is what I often cut 3mm at - so I was pretty happy that day!
And so far still fairly happy with the alignment.
But I am still getting an issue where sheet 1 of a pattern, cuts great but sheet 2 maybe great, sheet 3-4 stops cutting on far side and so on.
It seems the mirrors and their holders are getting hot to the touch - not burning but very warm - maybe 50degC. I think that either the tube is getting too warm (and tomorrow I will try and lower the limit on the chiller to see if that helps) or the expansion of the mirror and or the holders of the mirror is causing the alignment to go out of whack.
If I let things sit/cool down for a while, they go back to OK (or better at least).
Anyone with any experience or suggestions on this? How hot do the mirror holders get on a similar set up? My brother is running an 80w tube on the identical machine and does not seem to have an issue so maybe the mirrors are absorbing too much heat at 130w?
Its a PITA as my sample cuts seem great but my production goes to pot.
Thanks, GF