I have an A20M dual extruder printer of Geeetech. It has 2 similar extruder stepper motors which feed 1 mixing nozzle via seperate bowden tubes.


I'm bussy re-calibrating the printer. And ofcourse began with calibrating the extruder steppers.


But I've found out that E1 feeds around 1mm more (without nozzle connected) then E0 does (feeding 100mm). I can't seperately configure the steps/mm because Marlin 2.0.x seems to refuse this when MIXING_EXTRUDER is configured.
It only shows me 1 E-stepper setting. And it uses the same value for E0 and E1.


Idler spring tensions seems to be equal, so guess this is not the problem.


I also changed the cables from one to another and tested again. Which gave me the same results on the same motors. So it's also nothing with electronics or stepper-driver settings/resistance.


So I guess it's some diffrence in tolerance of the motors itself? Is there a way to compensate the diffrences?