esteps vs multiplier

[hackinistrator]

oh well , i always thought calibrating esteps is unnecessary , as i can adjust my extrusion to my liking with just changing the extrusion multiplier .
it seems i was wrong , i think .
i print allot of carbon fiber filament and i didn't take into account the extruder gear wear .
i was compensating the wear by increasing the multiplier , but it seems that it also has negative effect on printing . so i recalibrated the extruder esteps and starting from scratch .
i still dont understand what can cause the difference in software . the only thing i can think of is retraction , as the software setting is in mm , which is related to esteps and not multiplier .
i tried printing without retractions (+linear advance or pressure advance turned off) and having same difference .
any idea?

[Phaedrux]

Did setting the correct esteps work?

I would have thought that setting esteps and changing the multiplier would have worked the same way, but maybe it is as you say and there are cases where it's treated differently.

Normally I would say to get the esteps close and then adjust the fine tuning with the slicer multiplier or firmware multiplier, but perhaps there are limits to that.

How much multiplier were you having to add?

[hackinistrator]

i was around 1.1-1.06 on multiplier , depends on filament .
when checked esteps , i was extruding around 90% (tested with 100mm filament)

[zapta]

@Phaedrux said in esteps vs multiplier:

but maybe it is as you say and there are cases where it's treated differently.

I also assumed that but on a second thought, they may be different, at least theoretically.

For example, imagine that you cut the esteps by half and compensate with the extrusion multiplier. The rate of the motor steps will stay the same but the duet will consider it to be twice the mm/s speed, and therefore apply differently jerk, constrains such as jerk and max speed.

[dc42]

Changing E steps/mm and changing the extrusion multiplier have the same effect, except as follows:

1. If you use firmware retraction then the extrusion multiplier is not taken into account during retraction and reprime moves.
2. The extruder acceleration, maximum speed and jerk limits will kick in a little sooner if you increase the extrusion multiplier.

I calibrate the E steps/mm just once, then I adjust the extrusion multiplier to suit different filaments if needed. I rarely need an adjustment of more than +/- 5%.

[zapta]

Another example that comes to mind is the start G-code purge line. It's effected by the esteps settings but not by the multiplier.

[dc42]

@zapta said in esteps vs multiplier:

Another example that comes to mind is the start G-code purge line. It's effected by the esteps settings but not by the multiplier.

Yes, likewise retract/reprime moves in pause.g and resume.g.