Firmware Request - high Z position during preheat
When "Preheat" is selected on the MK2, I think it would be convenient to have Z move up to about +120 so the oozing filament builds a little mass to help draw it down and away from the nozzle. It is easier to grab and get out of the way before the print begins. What I do now is move to home and then move Z with the wheel then select preheat.
I guess a g-code program could be written to do this instead....Easy enough to load and keep it on the SD card. I don't know how to write the g-code though...yet.
Tom Cole
Re: Firmware Request - high Z position during preheat
I second this request, not only for the reason stated by OP, but also because if the PINDA probe is too close to the bed during preheat it seems to cause problems with readings, as notated by numerous other users on on this forum.
Re: Firmware Request - high Z position during preheat
Emptying the filament chamber before starting the print is not a great idea. You need to bring the extruder up to print temperature with the nozzle close to the bed; this then allows only a small blob of filament to ooze prior to printing and ensures that there is filament for the pre-extrude and/or skirt.
It is rather simple to amend the start GCode to heat nozzle to 170 degrees and bed to full temperature with the nozzle high, then home and 9-point calibration and finally heat nozzle to print temperature.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Firmware Request - high Z position during preheat
Emptying the filament chamber before starting the print is not a great idea. You need to bring the extruder up to print temperature with the nozzle close to the bed; this then allows only a small blob of filament to ooze prior to printing and ensures that there is filament for the pre-extrude and/or skirt.
It is rather simple to amend the start GCode to heat nozzle to 170 degrees and bed to full temperature with the nozzle high, then home and 9-point calibration and finally heat nozzle to print temperature.
Peter
I would agree, except for the fact that I haven't seen a single instance, even with particularly runny filaments like nGen, where the pre-print purge line in the lower left of the bed doesn't bring in enough filament into the chamber prior to printing.
Furthermore, since overheating the PINDA probe seems to alter it's behavior (something more than a handful of others have had an issue with on the forum, even if you haven't observed any issues personally) this is something that should be addressed in firmware and not in gcode since it potentially impacts the normal operation of the printer.
I suppose the alternative behavior to address calibration issues, although it would add a substantial delay, would be to move the nozzle away from the bed, complete preheating of the bed, execute MBL, then pre-heat nozzle. This would also potentially minimize the amount of excess filament that blobs up as the printer would be able to start printing the moment the nozzle comes up to temperature.