[BUG] Perform a small extrusion prior to unload

[Eldenroot]

Printer type - [MINI]

Printer firmware version - [e4.4.0]

Original or Custom firmware - [Original]

Optional upgrades - [Filament Runout Sensor]

USB drive or USB/Octoprint
USB

Describe the bug
I use M600 a lot, unfortunately filament (new one, Prusament - so completely dry) stuck inside the extruder during unloading. The small tip blocks the output. Same issue was discussed for MK3 Prusa -
prusa3d/Prusa-Firmware#2318
prusa3d/Prusa-Firmware#417

How to reproduce
Unload filament (PLA)

Expected behavior
Slower unloading

G-code

Crash dump file

Video

[Prusa-Support]

Thanks for your suggestion.

This behavior was already improved in the past with FW 4.1.0 and 4.3.3.

This behavior may change though if the M600 command is not directly prompted by the firmware itself (for example if you are printing via serial line). I may seem to understand that you are regularly printing via USB flash drive though, so this shouldn't be a concern. Is that right?

Also, consider double-checking or replacing the hotend PTFE tube. If such tube is deformed, out-of-specs, or simply shaking together with the filament movements, it may cause irregular tips at the end of the filament.
Same applies to the hotend metal parts: even a tiny gap between heat-break and nozzle can cause irregular tips.

Michele Moramarco
Prusa Research

[capi92]

Hi,

got the same issues on mk4 especially with 0.25 Nextruder nozzle.
As is, 0.25 nozzle are not usable with m600.
will check if immediate filament switch would improve, I used to be away thus coming back when printer is beeping I.e 30 / 60 seconds later, filament being cold can’t be pushed again in nozzle…

I have a small drop on top of the Nextruder nozzle that need nozzle to be dismantle to be cleaned up.

printing via usb.

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