PINDA Problem???
I have a MK2S which had been printing consistently with both PLA and ABS without problem. Then, after moving to an enclosure (an unused cabinet in my garage), printing PLA on a cold night (outdoor temp around freezing) with a heat lamp to keep the enclosure warm, when I checked-in on the print's progress a couple hours in, I found the print had detached, and a large glob of PLA encasing the extruder. Further, based on the reported bed temperature (which had been set to 55) the enclosure had heated to at least 80. (Seems to have ruined the roll of PLA - filament strands sticking to each other on the roll.)
But the real problem is that I can no longer achieve an accurate Live-Z adjustment. Running a 1st layer calibration yields significantly different outcomes from one run to the next. I have carefully reset the PINDA height in relation to the extruder, and re-run the full calibration routines and all report good results. But, again, running a 1st Layer cal, the live-z value can wander by up to several hundred microns!!! And, if I can finally get a 1st layer cal that looks right, when I attempt to print, the extruder can end-up skating on the PEI surface, requiring an "emergency" live-z backing off. Attempting to print following this I am usually able to get a print after several attempts, adjusting live-z repeatedly until all works. But, attempting the same print again ends up with z totally out of whack again... 🙁
So, since I have a tendency to replace the most expensive parts first, working my way down to the actual failed, cheaper(est) part, am I on the right track with my assessment that I've managed to damage the PINDA sensor?
Re: PINDA Problem???
Probably, it could be worse too. electronics, power supply in an enclosure at 80c? not an ideal environment. if still does it at Room temp (20-23c) then probably is broke or something else is.
Re: PINDA Problem???
Solved!!!
Well, it's not the PINDA! Happy to say. Ran the recently posted PINDA tests and the first two confirmed the PINDA was working.
However, when setting up I noted that invoking Auto Home managed to drive the extruder into the plate! Ok, some mechanical issue.
On manual inspection my bed was way out of level (by about 3mm).
Over time some of the nuts had loosened (or were never properly tightened???), and the clean-up (manipulating the entire printer in all three axis) after over-heated enclosure threw everything out of alignment.
Interestingly, the XYZ calibration reported Success!
But the wanderning Live-Z during 1st layer cal should have been a tipoff.
So, after a couple hours of painstakingly mechanically releveling, it's printing consistently. The Live-Z is still high (-0.980), but for now OK. I wiil be addressing that when I have just a bit more time.
Re: PINDA Problem???
The PINDA on MK2(S) has a known problem, the sensitivity drifts with temperature, therefore the height at which it detects the heatbed changes too.
I had to replace the whole head, including thermistor, because of a blob of ABS caused by this temperature drift.
They've fixed it in MK2.5 and MK3, but they won't backport the fix to MK2(S) for some reason.