Uneven extrusion
This started with my first print this morning. My last print yesterday had no problems.
A calibration print shows the uneveness better:
Not a nice, neat straight line. It looks almost cyclic.
I noticed that when unloading filament, there was almost no tension while pulling it up. There had always been a slight "grab" from the idler before this morning. I tried adding a little more tension to the idler, but that didn't change the print or the tension. Filament feeds fine and the color test strand looks normal.
Any ideas on what I need look for?
RE: Uneven extrusion UPDATE
I had turned the printer off. After about 1/2 hour, I thought I'd try a MK I eyeball and maybe get a better idea of what and where things were going wrong. I turned the printer back on and a started a first layer calibration print. It was immediately apparent that it was printing just fine. I let the print complete and it was perfect.
I changed filament and this time, there was the normal tension unloading the filament.
Two 1/2 hour prints later and it's again printing perfectly.
Obviously, the problem is NOT solved, but at this point I have no idea what the issue is or how to begin to diagnose it. Firmware == 3.13.1
That first layer is definitely calibrated too low, if this is sudden, combined with your change of tension, it sounds like something has come loose.
First check the SuperPINDA mount is firm. Next the extruder carriage - this shouldn't be too tight so if it's less obvious if the screws loosen. A general run through the regular maintenance schedule won't hurt and will help you spot anomalies: https://help.prusa3d.com/en/article/i3-printers-regular-maintenance_2072
There are also, less likely, possibilities that include collapsed bearings but run through the above first, recalibrate the first layer 'Z' offset and try aain. Come back if the problem persists.
Cheerio,