Nozzle cleaning fail
The continued Core One nozzle clean fail with PETG filament, after a couple of prints normal is a fail - manual nozzle clean and restart print - very frustrating. My MK3S+ - MK3.5 I press print and feel confident of a trouble free print.
With my Core One (factory assembled) can I not press print and feel confident about the result - don't get me wrong, I am blind to all other printer brands - this has to be fixed by Prusa.
The alternative is reputation damage to the Core One
RE: Nozzle cleaning fail
Which firmware are you running?
RE: Nozzle cleaning fail
Hi.
firmware 6.3.3
RE:
My current idea about this:
Search for Custom Start G-Code, that disables the hotend heating during probing. Apparently, the heater is interfering with the loadcell and the "Nozzle Cleaning" G-Code command is simply to probe a little area at the front, not fancy G-Code that "cleans".
When I disable the heating during Homing, then heating back up, disable for the Nozzle Cleaning, heating back up and then again disable heating during the real print bed probing:
Short Homing, no Nozzle cleaning fails, probing every point just a single time.
I guess PETG Nozzle Cleaning fails more often due to the hotend having to spend more energy for the higher temperature.
Sadly, the mesh bed leveling suffers a tiny bit, due to the nozzle becoming a bit shorter, when dropping in temperature. But I didn't encounter issues or an ugly first layer yet.
Hopefully Prusa can implement something in the Firmware that disables the heating only for the Z-Moves during probing commands, so the hotend stays at its temperature.
RE: Nozzle cleaning fail
Support told me it's a known bug and a fix is coming. Workaround was some custom g-code. See attached screenshot.
RE: Nozzle cleaning fail
Thanks for the feedback - great to hear Prusa is on it. I will try the GCode fix in the interim
RE: Nozzle cleaning fail
I stick a small strip of thin tape (FrogTape Yellow) in the nozzle cleaning area, the failures have been rare since then.
RE: Nozzle cleaning fail
Interesting. I recently raised a support issue about failed nozzle cleaning as well as failed bed probing. While they did supply code without the heating during nozzle cleaning (but did not explain at all what they were doing), they also did send a new load cell and main cable. With some help on the forum I figured out how to disable heating during probing/cleaning, and have been able to print in the meantime.
I also noticed that my load cell values changed a LOT between finger taps. I mean at first it's somewhere around 800 or so, and a tap brings it down to -100 or so, but then a minute later we have a single digit baseline and it goes way negative. This is not normal behavior for a load cell. But it's also concerning to me that disabling heating would impact anything for anyone. I have personally assembled from bare strain gauges literally thousands of load cells, wired and calibrated them. If heating is impacting the load cell signal someone did not do their hardware homework designing this part. These things are a tiny signal, and massively susceptible to noise, not planning for this is pretty bad. I would imagine that the only software fix possible would be a more advanced turn off heater only during the actual touch move. But if it is influenced to that degree it is straight up a bad design.
Have not yet changed out the cable and load cell on mine, but the disabling heaters does work at least for the moment.
Support told me it's a known bug and a fix is coming. Workaround was some custom g-code. See attached screenshot.
RE: Nozzle cleaning fail
GCode file change certainly improves reliability .......
