Step loss/XY crash when printing with a full print bed
Hello,
The C1+ is my first printer, I assembled it myself and it works great.
During a print with the print bed fully filled, I experienced a crash? or a loss of steps in the XY direction. I heard the crash as a sound (metal on metal), however I don't know if it was the result of step losses or the cause of the step losses.
Is there a way to "simulate" G-code on the printer only for the motion system, without printing? I would like to repeat the print coordinates without printing, in order to test whether I can reproduce the step loss. Is there a procedure for this?
Thx!
RE:
I guess you can disable both filament sensors and run the printer "empty", without filament? Haven't tried this myself though.
But maybe we can find a shortcut to troubleshooting this. A few typical reasons for step loss have been described by others:
- Use of the "avoid crossing perimeters" option in PrusaSlicer generates invalid Gcode with impossible accelerations. The printer does not actually experience a physical collision, but cannot follow that ultra-fast movement. The option must be avoided until Prusa finally fixes the bug in the slicer.
- The umbilical cord to the print head can sag (especially if not properly tied to the PTFE tube) and get caught.
- Prints can come loose from the print bed, typically at a corner, and curl upward -- resulting in a collision of the nozzle with the printed object.
Maybe one of the above is also the root cause in your case?
RE: Step loss/XY crash when printing with a full print bed
Check the umbilical whether it can jam under any circumstances. Then, objects coming partially loose from the print bed, overhangs curling up. Or severe overextrusion.
What usually happens:
- the print head gets stuck in the print for one of the above reasons
- a stepper slips (skips steps) and continues printing happily with an offset
- eventually, when a feature or planned movement shifts outside the mechanic range, the head runs - possibly full speed - into the end stop and that's the metallic noise. Sooner or later it'll happen on every printer. It will survive but diagnosing the root cause can be tricky. Check the print bed for any "evidence" of collisions. Molten blobs from a dripping nozzle can cause the same but this would be unlikely without material change (as in the MMU).
RE: Step loss/XY crash when printing with a full print bed
well... I didn't see Jürgen's post, for whatever reasons. Anyway, you now have a second opinion on the key items 🙂