G1 command runs BACKWARDS after Load

Snapmaker 2.0
1

I was trying to calibrate my extruder this evening, and ran into trouble:

  1. Connect Luban to SM2 via serial USB (Mine’s on COM3)
  2. Open Controls page on touchscreen
  3. Let it finish the homing procedure
  4. Turn on the nozzle to 200, let it heat up.
  5. Press “Load”, and feed the filament through (I was using SM2-default filament)
  6. Enter G1 E100 F300 command into Luban shell
  7. Note that the filament goes BACKWARDS, and unloads from the module

I noticed other weirdness, too:

  • Only the first G1 E100 F300 command ever worked for me. After running it once, I had to turn it off and back on again
  • When G1 failed (i.e. the second time I ran it):
    • one time it printed some kind of information: X:-19.00 Y:347.00 Z:327.20 E:100.00 Count X:0 Y:142800 Z:133600 but failed to extrude anything.
    • one time it said Enclosure online: Off. I don’t have an enclosure.
  • My extruder calibration came off 17.8mm short on a 100mm extrusion (!!!). So my new E value is 258.12, which seems really high - almost 20% off!? (I wondered for a moment if maybe 258 was overflowing 8 bits and causing it to extrude backwards, but of course, no - it’s floating point, so obviously 256 is not MAX_VALUE.)

The problem persisted even after multiple reboots - I was able to repro it 5 or 6 time tonight, I’d have to check my journal. I keep detailed notes about everything I do, so if you need more info, LMK.

2

Did you enter M83 to enter the relative mode? You have to to that before the G1 E100 F300.

3 Likes
3

M83 for relative mode is needed, like @FlyByWire mentioned.

Is your filament tension free? - The best way for calibration would be to cut the filament, so the extruder could pull easily.

Snapmaker firmware has a runout protection to save filament, you could just extrude 50mm per gcode line. (sure I have seen different behavior, but so it is)

I would suggest you to extrude a bit slower, like F100. So filament could not slip that easy.

After assembling my machine, it was 10% off but I had to give it 10% more after a couple of months, maybe depending on other filament, so this sounds normal.

1 Like
4

Awesome - nope - didn’t enter M83, thanks xchrid and flybywire! Always learning. I was working off the Extruder Calibration thread, and missed that.

I’ll try again tonight with slower F value - good suggestion. Will also make sure there’s no tension on the filament.

Thanks for the help! Such a great community here! :slight_smile:

1 Like