resume redundant extrusion

bugpwr

There seems to be additional extrusion when resuming a job, which is not part of what's done by resume.g. It happens at a very different speed (faster), right after the macro has done its thing.

My guesss is some kind of relative/absolute extrusion mixup when returning to the correct gcode position within the job - meaning, the redundant extrusion comes from what is written in the job file itself. Stems from rrf forum topic 416,832302,896231.

For reference, here's my pause/resume.g.

; pause.g
M83 ; relative extruder moves
G1 E-10 F3600 ; retract 10mm of filament
G91 ; relative positioning
G1 Z20 F360 ; lift Z
G1 Y-30 F6000

; resume.g
G1 R1 X0 Y0 F6000 ; move XY first to saved pos
G1 R1 X0 Y0 Z5 F6000 ; go to 5mm above position of the last print move

G1 R1 X0 Y0 Z0 F6000 ; go back to the last print move
M400 ; wait for moves to complete
M83 ; relative extruder moves
G1 E10 F300

Opening this here due to dc42's advice.

Phaedrux

Firmware version? Which Duet board?

bugpwr

@Phaedrux Duet2Wifi, FW 3.5.4 but also tried with 3.6.0 beta 1.

Phaedrux

@bugpwr said in resume redundant extrusion:

There seems to be additional extrusion when resuming a job

Can you show a photo of what you mean?

bugpwr

@Phaedrux I will make a video later as this huge printer is now printing, but let me try to describe the steps clearer:

start print
pause in the middle of the print. wait until paused. 10mm retract occurs as it should. print is now paused.
resume the print. unretract (extrude) of 10mm happens accordung to resume.g. This has no effect because it was retracted before.
printer now extrudes another 5 to 15 mm for no reason, very quickly, much quicker than the F rate specification of the respective command in resume.g
printing resumes with an ugly blob. this happens almost every single resume.

droftarts

@bugpwr Original thread is here: https://reprap.org/forum/read.php?416,832302

Please post your config.g, and the gcode (or a test gcode) that exhibits the problem. Are you pausing in the middle of a long move? Are you using absolute extrusion? Do you have segmentation enabled?

Please could you also test with RRF 3.6.0-beta.2, as this issue may already have been fixed. https://github.com/Duet3D/RepRapFirmware/releases/tag/3.6.0-beta.2

Ian