# Marlin: Why is the extruder stepper jerking?

Environment:

• Printer: Anycubic Chiron,
• Firmware: Marlin 2.0.7.2,
• Settings: FWRETRACT is not enabled,
• Slicer: Cura 4.8.0.

When I print using the code below (it is longer, but I do not know where to put attachments), I can see that the extruder-gear is jerking, as if it tries to do tiny retractions between every little movement. Real retractions happens where they should and seems fine. If I slow down the printing from F2400 to F600, it is almost gone. I don't say it is a problem, the printer works. I wonder if there are settings that can cause this, if it is as expected or if I can do anything to make my printer work more quietly.

Short film

; example G-code for noisy extruder stepper
; PLEASE DO NOT RUN ON YOUR PRINTER unless you know what it does.
M302 P1 ; disable cold extrusion checking
G0 Z5
G0 F2400 X214.8 Y177.1
G1 F600 Z5
G1 F2400 E0.20522
G1 X214.866 Y177.134 E0.20647
G1 X214.934 Y177.161 E0.20890
G1 X214.923 Y177.189 E0.20990
G1 X214.912 Y177.217 E0.21090
G1 X214.907 Y177.229 E0.21133
G1 X214.813 Y177.456 E0.21927
G1 X214.793 Y177.480 E0.22031
G1 X214.540 Y177.791 E0.23364
G1 X213.982 Y178.218 E0.25701
G1 X214.155 Y178.986 E0.28319
G1 X214.757 Y179.315 E0.30601
G1 X214.962 Y179.542 E0.31618
G1 X214.990 Y179.574 E0.31760
G1 X215.109 Y179.775 E0.32537
G1 X215.124 Y179.801 E0.32637
G1 X215.140 Y179.827 E0.32738
G1 X215.105 Y179.848 E0.32874

• I have absolutely the same problem with my custom build printer. I think it's the voltage/current the stepper driver provides, but didn't have time to test it yet. I hope someone can provide an useful answer. – Kev Inski Feb 16 at 5:44
• You can post your movie on YouTube or something similar and post a link here. – 0scar Feb 16 at 8:18
• Quite good analysis of basic possible causes. Could this be just extrusion wheel slipping on filament - or stepper looksing steps due to pressure? – octopus8 Feb 16 at 18:57
• I have bad roller-bearings. That cause extrusion wheel and stepper-motor wheel to be further apart at some parts of every turn of the extrusion wheel. This explains the noise. – dotswe Feb 16 at 21:19
• But it does not explain that the stepper seems to retract a tiny bit after many/every G1 movements. I have today tested to increase/decrease current through the stepper. Normal voltage for Chiron stepper seems to be around 0.9V. I run the E-stepper at 0.7V. I tested up to 1.3V, but that made no difference. At 0.5V, I could force rotation by hand, so the stepper got weaker as expected. – dotswe Feb 16 at 21:27

The setting that makes these small retractions is LIN_ADVANCE. It is found in Configuration_adv.h and is disabled in the vanilla configuration.

I, on the other hand, is using one of the 46 example configurations that has this feature enabled. It shall be said that most of them them has the value 0 set to this, which means that it has no effect.

To disable the effect of this feature, send G-code M900 K0 to the printer.