All,
I think the problem has been resolved, so I wanted to report back. I did file a support ticket, and Formlabs quickly helped out. After some diagnosis, I was basically advised to take two steps, clean the optical window and clean/lube x-axis:
When I went to clean/lube the x-axis rod, I was surprised to find very visible contamination. In retrospect, I should have just opened the printer and looked around with a flashlight, it would have been obvious something there was abnormal. Attached are a few pictures showing segments of the x-axis with what little “shavings” of black junk that have fallen on the floor of the printer under the x-axis rod (see arrows pointing to specific location in the photos). I could even see some accumulating around the hole where the x-axis enters the LPU.
So I just vacuumed out the shavings, cleaned the rod with a clean rag, and applied some white lithium lubricant. I have white lithium grease that I use on all my printers…FDM, SLA, SLS, etc. they all have positioning rods. After that you just move the x-axis back and forth a few times to spread it around. I also cleaned the top of the optical glass per the instructions above (PEC PADs).
Next three prints were all successful, no problems. Given that I had about 5 failed attempts in a row before that, I think it is safe to say that cleaning the x-axis rod really helped. Since I cleaned the optics at the same time as the rod, I cannot say with certainty which made the difference; but given the visible evidence of problems with the x-axis, I’m going to speculate that was the key issue.
Anyway, if anybody else has this problem, I would advise: (1) remove the tank and look around with a flashlight. Do you see this kind of junk under and on the x-axis? (2) If so, remove it and grease the rod. It took about 2 minutes of work.
