After installing a direct drive extruder (E3D Hemera) to my CR-10S, I calibrated the E-steps so that adequate extrusion would happen; going from ~95 steps/mm to ~390 steps/mm.
I had a couple of days of mostly successful prints. Some under extrusion (or no extrusion) happened here and there, solved by calibrating Vref for my extruder (from 455 mA to ~800 mA). I was then able to print a thing or two.
Then, after a couple of days, I had major under extrusion problems. (To the point that it looked like only the infill was being mostly printed despite using the same slice settings on past successful prints.) I looked up under extrusion causes (temp, bed level, speeds, idler tension, etc) and nothing seemed to apply, except for idler tension, which I cranked up.
Despite being certain that I didn't do anything to reset my step settings (namely resetting EEPROM) I decided that I might as well check to see what my steps are set to. Lo and behold, my steps were back down to 95. No wonder I was under extruding, I was only pushing a quarter of plastic out! Sending an
M92 I was able to get the E-steps back to where they belong. Benchy came out with some droopy layers, so I was over extruding. I tweaked the idler tension (since I cranked it tight earlier) and for the most part that seemed to help. I came to have other issues (like a potential clogged nozzle) so I'm not sure how much calibration is needed as plastic isn't feeding, but I digress...
What could have happened to cause my e-steps to reset? The obvious being resetting the EEPROM, which I am most sure I didn't do. Is there anything else that could have happened?
Printer: Creality CR-10S
Firmware: TH3D Unified Firmware U1.R2.22 (or one/two versions before it maybe) (firmware is Marlin based)
Extra: OctoPi (Unsure of version, possibly most recent stable release) Other than starting prints, only used to set E steps and
G0 commands before problem showed up.
As for future prevention of resetting to 95 steps/mm, I realize I just need to re-flash the firmware setting the E-steps to 390 or something.