I’ve had a MP Maker Select Plus for about 6 months. After the initial setup and calibration, I’ve printed over 100 models successfully (even parts-to-fit). My calibration/leveling/slicing seemed all dialed-in.
I’m mass printing some gifts for Christmas (some pokemon models, some coaster sets, etc). After printing 12 of the pokemon models in 2 different colors of PLA (they all turned out great), I changed colors for the next set of models. I started the next print and walked away. When I came back about 30 minutes later there was an obvious problem.
I was using a raft for this print as the model had a small footprint. The raft had not printed. Instead the nozzle had descended into the print bed and scarred it throughout the entire raft portion of the print, ruining the factory mat which covers the build plate (I’m not sure what this is made of). The model itself did print with little issue, other than the missing raft and the first few layers being rough as a result of the scarring.
I removed the damaged mat, as well as the residual adhesive. There was a massive amount of adhesive and I had to try a few solvents to completely remove it. As an aside, Goof Off Pro Strength Remover worked best and after some hard work with a plastic putty knife, the print bed was pristine. I installed the new mat (the printer shipped with a spare) and began trying to determine what caused the problem in the first place.
I am still unsure how this could have occurred. Moving the Z-axis to 0 now causes the nozzle to push into and below the bed surface, even with the leveling screws/springs completely tightened. It seems that either Z0 is now at least 0.6mm lower than it had been (the raft was 6 layers at 0.1mm each) or the bed had risen at least 0.6mm. The other possibility I can think of is that the position of the nozzle relative to the X-axis has been lowered somehow. I did examine the X-axis motor/extruder assembly for any bending, but it seems solid. I can’t imagine how it would have been bent out of alignment.
I know I can move my Z stop switch up (there are 4 holes to mount this and it is currently in the bottom set of holes) and re-level the bed. But I am dumbfounded as to what caused the initial problem. More concerning is whether it will occur again.
Any input/advice would be greatly appreciated!
Probably no help, but did you cancel the print immediately prior to that print? On some models (and makes)
that can leave the on-board controller not-quite set up correctly for the next print. I’ve taken to power-cycling
my printer (a Monoprice Mini) if I cancel via the control panel. (I mostly run from Octoprint these days and have
experienced no problem after canceling via that software.)
Hope this helps.
Are you sure the z-stop switch was at the bottom in the first place? Over time, it could’ve loosened and fallen to the lower set of holes.
