Unwanted Filament unload at primer start

[FastLayers]

Hey,

Apologies if this is obvious or stupid, I am a newbie, I haven't had my prusa i3 mk2 kit assembled for very long.

To make a long story short(been troubleshooting for a few days now, unable to duplicate in another slicer), is there a setting that would cause the filament to basically fully unload right at the start of a primer?

t.extrusion_steps_mini.gcode

Gcode with unwanted filament unload at primer start

(62.67 KiB) Downloaded 185 times

I've uploaded a gcode file where this is happening. To accurately describe the issue, the filament gets basically entirely unloaded right at the start of the prime but I am lost as to why.

Thanks!

[CompoundCarl]

Well, you want to look for G1 moves that have an E value. Those are the ones that will be priming or extruding.

Can you try putting a "G92 E0" before the line that says "G1 X60.0 E9.0 F1000.0 ; priming". Maybe you need to zero the printer first if you just got gone with another print.

[FastLayers]

Well, you want to look for G1 moves that have an E value. Those are the ones that will be priming or extruding.

Can you try putting a "G92 E0" before the line that says "G1 X60.0 E9.0 F1000.0 ; priming". Maybe you need to zero the printer first if you just got gone with another print.

Thanks so much for the reply Carl. I did a bunch of playing around yesterday and tried the 'relative extrusion distances(RED)' check box, seemed to make the problem vanish. Checked the gcode, RED seems to remove G92 E0 entirely.

I tried having just the 'allow zeroing (G92 E0)' option and moving it up three lines as you suggest (thanks again) and it seems to solve the problem as well. I think for now, I might just omit the G92 E0 stuff, but in reality I don't think I really grasp how to use G92 E0 or RED.

I doubt I understand why this G92 E0 issue exists, maybe there is a setting in my printers firmware I need to change?

[CompoundCarl]

Well it might be good to do a bit of reading on some gcode basics

The E-axis is just like any other. So if you tell it to move to a position, it has to move the extruder motor to get there. The problem was that it wasn't setting the initial position of the E-axis, so the printer didn't really know how far it had to travel. This usually isn't a problem for the XYZ axes, since the G28 homing command essentially sets an initial value for all of them.

The G92 E0 just sets the current E-position to zero