Fixing filament runout always causes XY shift in the print

Snapmaker J1/J1s
1

When the filament runout sensor (or clog sensor) says something is wrong with the filament on my Snapmaker J1 printer, it always is the case. When I fix the issue and load the filament, the printer has already homed the XY axis (and Z probably too). Now when the printer continues with the print, there is always a shift in XY. And this shift always happens. I think this is due to the homing procedure in between. I already have the latest firmware installed.

For that I wish to disable the homing feature in the routine of resolving the filament run out. I understood this is embeded in the M600 g-code command?

I would very much appreciate it if there was a possibility to not home during the routine of fixing the filament runout.

I am a software developer myself. As a last resort I could remove it from the code and recompile the firmware myself if needed. Of course, if there is a more user friendly way to achieve resolving the XY shift I would be more happy with that :smile:.

From the M600 g-code implemetation here, I read the following:

  #if ENABLED(HOME_BEFORE_FILAMENT_CHANGE)
    // If needed, home before parking for filament change
    home_if_needed(true);
  #endif

What ways are there to set HOME_BEFORE_FILAMENT_CHANGE to false?

Thanks.

2

It would be good if you let it the snapmaker devs know and correct:
Support@snapmaker.com or
Support Ticket Form

3

Your J1 has a filament runout sensor??? Mine does not, and Iā€™m trying to figure out how to add one.

4

All J1 models have a runout sensor, it is however very different from what normal runout sensors look like as it uses a extruder gear to drive a rotary encoder therefore it can detect not just filament runout but under extrusion as well.

Its the orange part above the extruder gears in this image:

image
image720Ɨ720 90.9 KB

1 Like
5

OK. I found the ā€œRunout Sensorā€ setting in the Configuration screen, and they are both enabled, but, they donā€™t seem to do anything. I have had prints merrily continue printing after the filament has run out. Shouldnā€™t it pause and wait for more filament to be loaded?

6

Yes it should, seems like you might have to contact Snapmaker support regarding this issue as I have not personally ran into any issues with the sensor on my unit.

Perhaps check your slicer settings as it may be overridden by G-code, check for M412 in your sliced G-codes.

7

I have not done a thorough investigation, but it appears that the filament runout sensor does not communicate thru the USB-B connector in the back of the printer, which is how I use my printer. [Octoprint running on a Raspberry Pi connected to USB-B]. It seems that some of the J1ā€™s functionality is actually in the front panel, not in the firmware.