Problem with Z-calibration or extrusion, maybe
Last month, I set up a MK3S. During configuration, I set the Z-adjustment to -0.608mm and it printed fine. The results looked like they were supposed to. Prints stuck to the bed properly. Everything was fine. Recently my wife had a print go bad that ended up with a big pile of filament encasing the extruder. We cleaned if off, but nothing is sticking now. I tried rerunning the Z-adjustment. With values up to about -0.800 mm, I get results like the first image below, clumpy on the edges and stringy in the middle. With values beyond that, I get results like the second image, where it looks like the extruder is dragging around part of the print. At -0.900 and beyond, I see thicker beads in the extruded lines every 3-5 mm and the lines are very thin. This makes me think the extruder is too close to the bed at that point. But when I start a gcode file that printed perfectly on the same device a week ago, the head moves 3-4 cm before the PLA starts adhering. And when the extruder makes a 90 degree turn, it drags the end of the extruded filament with it. This happens regardless of where the Z-adjustment is. I've tried between -0.600mm and -1.1mm with it still never sticking properly. I've also tried cleaning with 100% acetone and 99% isopropyl with no improvement.
Does any one have an idea what could be going wrong here?
Thanks.
RE: Problem with Z-calibration or extrusion, maybe
Guessing a bit... but it looks like you are not nearly low enough.
It can also be exacerbated by bad adhesion, where the print sheet is dirty - finger prints and hand lotion on the bed is a disaster. Alcohol does a great job of spreading oils evenly as an invisible but very real film. Soap and water at a kitchen sink - Dawn dish soap or local equiv - lots of hot water using only fresh paper towels toscrub and dry. Handle the sheet only by the edges. I rinse for about five minutes with the hottest water I can stand splashing on my hands.