[3.4.0beta7] new input shaper disturb pressure advance

Argo

Oh, sorry, I forgot.

Voron 2.4 with LGX extruder and Mosquito Hotend
Duet 3 Mini5+
Speed: 120 mm/s
Acceleration: 3.000 mm/s

And I know that it's still beta. I'm not complaining, just reporting

PLA, EI2 shaper and PA at 0.15:

Bottom right is almost ok but upper right corner overshoots. Normal PA values for PLA are 0.05 up to 0.7 for this setup.

PCR

@argo yes. PA has to be tuned again. And it depends which shaper you are using. I already opened a thread on it.

For me it's

Flow-IS-PA-Retract

PCR

@argo and yes my PA is now higher than before.

PCR

@argo https://forum.duet3d.com/topic/25831/input-shaping-and-pa Thats my thread. I done more testing too.

Argo

@pcr

Oh I did not look in General Discussion as this is a beta feature.

Were you able to produce the same results with a higher PA value?
If I increase my PA value too much with input shaping enabled some corners begin to starve.

I wonder if that's a wanted behaviour. Besides the Voron we also have a bed slinger printer with Klipper. PA almost did not change with input shaping enabled.

PCR

@argo it tuned my PA with this https://forum.duet3d.com/topic/25764/pressure-advance-tuning-with-conditional-g-code/

so first IS then this.

are you using arcwelder aswell? I had problems with PA and arcwelder before

Argo

Another discovery I made:

In order to get good sharp corners I have to bump up PA quite a bit. From 0.07 up to 0.18.

But then the infill has issues and begins to starve which is a expected behaviour from such a high PA value for PLA.

Edit:
Did another test with ZVD shaper: pressure advance is at 0.07 - 0.075 for PLA and corners look nike + infill is not starving.
I guess the shapers with longer shaper duration somehow mess with pressure advance right now?

Phaedrux

@argo said in [3.4.0beta6] new input shaper disturb pressure advance:

But then the infill has issues and begins to starve which is a expected behaviour from such a high PA value for PLA.

This is not uncommon with PA and it's recommended to compensate by increasing the infill overlap in the slicer.

Argo

@phaedrux

This would work if the effect is the same on all infill paths.
The last picture I posted has huge gap on one specific infill part. Other parts look fine though.
I don't really see a way to compensate this with the slicer without causing problems on other parts.

Argo

RRF 3.4b7:

I first calibrated my PA.

Then some real world testing with PA set to 0.064 and

To get rid of the bulging I would need to increase to very high PA values which does impact all other areas whilst printing like starving infill ends etc. (see pictures above).

Used input shaper: M593 P"zvdd" F54.32

With RRF 3.3 I had similar PA values but no overshooting corners.