(mis)adventures in Input Shaping

KP0005

oliof

Hi, I have a couple questions

which RRF version did you test with? There are known issues with IS in 3.4.6, it would be interesting to see whether 3.5.0-rc3 would give better results.
-Have you tried RRF with the values measured in Klipper?
Did you encounter any quality issues in RRF with IS enabled you did not without? I.e., blobs or layershifts with IS that didn't appear without.

KP0005

@oliof
RRF 3.5 RC3+ (last week, DC42's hotfix of the network issues from here https://forum.duet3d.com/post/332835)

I have tried MZV at both 40 and 50 Hz in RRF to basically no improvement over no shaping.

I haven't encountered layer shifting or blobbing in RRF, but some of the shapers caused sharp corners to print much worse. No such issue with Klipper.

oliof

two more questions: Safe to assume that apart from start/end gcode this was the same model(s)? Would you be willing to share a sliced file so people can try to recreate?

KP0005

@oliof
Sliced for Duet: ringing_tower_0.4n_0.2mm_PLA_MK3.9_9m.gcode
Sliced for Klipper: ringing_tower_0.4n_0.2mm_PLA_MK3.9_7m.gcode

KP0005

(I am trying to tune the printer to use Prusa MK3.9 profiles, since it shares most of the mechanics with it. My printer is a heavily modified MK2 with a homebrew version of the Bondtech MK3 extruder)

oliof

@gloomyandy possible good test case

KP0005

@oliof I know the Duet version has high jerk and mesh bed enabled. I have disabled those manually while printing. Haven't seen a improvement.

KP0005

Another thing I forgot to mention. Disabling pressure advance also didn't help.

KP0005

Photos! They're here!

MZV, frequency sweep from 36 to 56 Hz, jerk 300.

I did in the end notice some weird corner artifacts, I didn't pay much attention to this area before.

KP0005

All shapers except EI3. Reduced speed, so the bands are closer together. 38 Hz, 0.1 dampening factor.

Interestingly, the results do differ for small segments:

KP0005

MZV, no besh bed:

EI3, no mesh bed: it made shorter segments worse than baseline

KP0005

And now: Klipper MZV:

That's the harshest lighting I could manage. It's just perfect somehow.

KP0005

The different banding in the top and bottom half of each tower segment is (I think) because the move direction flips midway.

That's all I got so far. @oliof