Move Axis After Disabling Steppers

Lukrative · 17 Jul 2019, 05:28

I just switched to RepRap Firmware from Marlin, and I'm loving it so far. But as with any upgrade, there are some things that I really liked about the old version.

My nozzle usually oozes some amount of filament out at the end of a print. During homing, this oozed and solidified filament can sometimes hit the bed before the z probe triggers. Marlin used to let me move the axes in the positive direction before homing. So to get rid of the oozed filament, I would just raise the print head up away from the bed and clip away the offending filament.

Now if the nozzle is left close to the bed when the steppers are disabled, then to clear away the oozed filament I have to preheat the hot end when it's right next to the bed, and some amount of filament always oozes out and forms a small clump around the nozzle.

It's not a huge inconvenience, since I can preheat it, home it, raise it up, and spend some time picking at it with tweezers. But if there were a way to move the print head up to just clip the oozed filament away before it starts a blob, that would be great.

Thanks, y'all!

fma · 17 Jul 2019, 05:59

See: https://duet3d.dozuki.com/Wiki/Gcode#Section_G0_G1_Move

"G1 Xnnn Ynnn Znnn S2 Ignore endstops while moving. Also ignore if axis has not been homed. On Delta and CoreXY, axis letters refer to individual towers."

Lukrative · 17 Jul 2019, 06:42

Thanks for your comment! I had tried that and thought it didn't work, but I forgot to specify the feed rate, so it used the last feed rate, which was 0.5mm/min. I couldn't tell it was moving, and this reply got me to try again, but looking closer.

deckingman · 17 Jul 2019, 06:52

@lukrative You can do absolutely anything you want to home the printer. Pre heat the nozzle, move the bed, move any axis to any position, etc etc. Any of those things in any order. Just edit your homing files.

dc42 · 17 Jul 2019, 07:01

@deckingman said in Move Axis After Disabling Steppers:

@lukrative You can do absolutely anything you want to home the printer. Pre heat the nozzle, move the bed, move any axis to any position, etc etc. Any of those things in any order. Just edit your homing files.

For example, in homeall.g you could raise Z a little using G91 G1 S2 Znn, then use M291 to pop up a dialog box asking you to clip filament off the nozzle before touching/clicking on OK to continue with homing.

deckingman · 17 Jul 2019, 07:11

@lukrative Oh, and another little tip. If you add a retraction at the end of the print, say in the slicer end gcode section, it will alleviate or even eliminate the oozing you get as the hot end cools.