Input Shaping + Pressure Advance Artifact

evan38109

Try as I might, I can't get rid of these artifacts with any combination of IS and PA options.

Here's how it shows up in real prints. Note the gaps where it looks like some segments of certain layers just didn't print.

Here's a comparison with input shaping enabled + pressure advance enabled on the left (M593 P"ei2" F42.0 + M572 D0 S0.09); and only PA enabled on the right (M593 P"none" + M572 D0 S0.07). Same filament, gcode, printer, etc. Printed back to back, didn't even restart or re-home the printer. The one with IS disabled is fine.

Is anyone out there using both input shaping and pressure advance at the same time with v3.4.0?

Egon.Net

@evan38109 I'm having the very same problem, you are not alone.

Egon.Net

Any news about this issue?

evan38109

@egon-net I put this one down and figure I'll get back to it. I assume I'm doing something dumb somewhere.

In the meantime, I've got an accelerometer and cabling in the mail. I've been tuning manually by printing calibration towers and such, but I figure I should try the more rigorous approach eventually. I've also been tuning other elements of my printer. If you look closely, even the "good" prints above have some artifacts and could be better.

I'll probably revisit input shaping eventually, and I hope to be in the best possible place for it to succeed when I do.

CCS86

I can't see what you could be doing wrong here.

Printing the same gcode with IS on and off is about as isolated as it can get, and it shows a very noticeable quality issue.

Did you ever look at this @dc42 ?

gnydick

@CCS86 there is another very long thread about this. I didn't realize it's been at least 10 months since the problem started

dc42

@CCS86 yes we know that the current implementation of PA isn't ideal when IS is also used. We thought we could get away with not adjusting PA to account for IS, because Klipper doesn't either. But Klipper has got it wrong too.

I hope to address this before the RRF 3.5 release.

evan38109

Awesome! Thank you!

CCS86

@dc42 said in Input Shaping + Pressure Advance Artifact:

@CCS86 yes we know that the current implementation of PA isn't ideal when IS is also used. We thought we could get away with not adjusting PA to account for IS, because Klipper doesn't either. But Klipper has got it wrong too.

I hope to address this before the RRF 3.5 release.

Glad to hear that!

Any chance that some sort of PA smoothing might be implemented as well?

dc42

@CCS86 the main reason that Klipper uses PA smoothing is that it doesn't control extruder jerk, and without applying PA smoothing it's likely that the extruder would miss steps.