Last piece too short
Hello, I have a Palette 3 Pro, and I’m trying to print the calibration keychain. I’ve noticed that the print consistently runs out of filament at the very end, in the exact same spot.
I’m not sure, but I think this only started happening when I added some GCode to my “End of print” Sequence to do a “hot unload”, which basically boils down to: “retract the filament 46.5mm while the hot-end is still hot, so that when I need to unload that filament for the next print, I don’t have to heat up the hot end first”.
Sure enough, when I…
- Take out the retracted leftover piece from the previous print,
- Feed a piece of filament through the extruder to the (cold) hot-end, and
- Compare the lengths,
…the leftover piece is almost 4cm shorter.
(True, it’s not exactly 46.5mm short, but it’s close enough to make me raise an eyebrow. And, if you add on the filament that’s still in the hot-end, and the filament string that comes out attached to the end of the leftover piece… hmmm :) )
What I think is happening is that the Palette sees that 46.5mm retraction in the “End of print” sequence, and subtracts that length from the length of the final piece. And since the Palette cuts the filament at the end of the print, that’s 46.5mm of filament that never makes it to the extruder… which causes the printer to run out of filament at the end of the print.
I’ll test this by commenting-out my 46.5mm retraction GCode. If the print finishes without running out of filament, then I know my 46.5mm retraction is to blame :)
If I’m right about this, then this begs the question: is there a “right” way to do a “hot unload” at the end of the print, that won’t confuse the Palette?
I read somewhere that underextrusion could be caused by the Bowden tube length being configured too short in the Palette, so I’ve increased that setting by 4cm — twice — and, both times, the leftover piece is still short by the exact same amount. So I don’t think that’s it :)
Is this a good question?