Nozzle cleaning usually fails, bed levelling works perfectly.
What's the logic for nozzle cleaning? - how does it decide when the data is good, and when it is not?
The load sensor value was around 2000 , with jitter of about 50 - after "load cell test" (or similar, somehow not called calibration like the neighbouring items in the menu) - I got it to about 100, with a jitter of 50. (with filament unloaded.)
I did not yet test if that fixed anything, but so far, the nozzle cleaning failed on most prints, levelling proved good.
I wish Prusa described the exact logic involved, maybe it would be easier to understand what's going on, also, faster refresh rate in the info-screen , or a graph could help.
RE: Nozzle cleaning usually fails, bed levelling works perfectly.
Getting the same failure now but it is every print. Prusa says its some pinched or damaged wire in the bundle to the hotend, but havent told me which cable exactly.
They had me test by modifying the start gcode before the clean command to both turn off the nozzle heater, then tried with it set to 240.
It passes when set to 240 and fails when set to zero.
test 1
M84 E ; turn off E motor M104 S240 ; added this line for test G28 Q ;home all without mesh bed level
test 2
M84 E ; turn off E motor M104 S240 ; added this line for test G28 Q ;home all without mesh bed level
RE: Nozzle cleaning usually fails, bed levelling works perfectly.
Does any cable pull on the hotend and add mechanical force on the loadcell sensor? I understand this adds to the loadcell sensor readings and can confuse the SW e.g. if it behaves slightly hysteretic.
RE: Nozzle cleaning usually fails, bed levelling works perfectly.
My contact with the support asked me to try to turn the temperature off using the tuning screen just before/at the nozzle cleaning, and it worked perfectly (but waiting for that is clearly not optimal)
I asked for the technical reason, and support tech said that the if the loveboard-connecting cable was pinched there could be interference from the heater.
I should receive a new cable soon, and hopefully there will be some instructions on how to replace it.
RE: Nozzle cleaning usually fails, bed levelling works perfectly.
Interesting, thanks for the extra detail. Guess its the same for me. What i cant figure out is why its only affected my hardened steel nozzle so far
RE: Nozzle cleaning usually fails, bed levelling works perfectly.
That would not make any sense (given how it works)
My error went away temporarily over time too, I would guess your interaction with the assembly is more likely to be the case, than the minimal weight difference between those nozzles. (given, of course, that they are clean.)
RE: Nozzle cleaning usually fails, bed levelling works perfectly.
This is a long standing issue with the love board and load cell on the Core One's. The consensus is that the heater PWM signal is interfering with the load cell readings. Setting the nozzle temperature to a fixed value in start-up gcode will mitigate this. Another work-around is to install a nozzle wiper mod (found on Printables) and comment out the nozzle cleaning procedure: ;G29 P9 X208 Y-2.5 W32 H4
A third way is to remove the signal and ground heater wires (I believe there are 2 pairs) from the cable harness, twist them and reinsert.
Short answer is that it's a hardware bug that still hasn't been fixed by Prusa.