Input shaper vs. max. volumetric printing

[o_lampe]

Hi gents,
tldr; It would be nice to have an IS algorithm which can handle speed variation

I often print parts with variable layer height for overhanging parts. Since the bottleneck of my printer is the DD-extruder, I can print much faster when the layerheight is small.
I haven't used PrusaSlicers max. volumetric speed feature, but I tend to increase the speedfactor in DWC manually when layerheight is low.
This unfortunately messes up my IS-calibration and I see ringing.

[jay_s_uk]

@o_lampe maybe try 3.6 alpha 2? it would be interesting to see if you still experience the same amount of ringing

[o_lampe]

@jay_s_uk I'm still on 3.4.6 on a Duet2 board. IIRC there are limits regarding this board and IS.
Haven't read the release notes of rrf3.6 yet, but I don't expect miracles.
As I understood the new IS algo supports shorter tracks, but is still calibrated for a fixed printspeed, no?

[jay_s_uk]

@o_lampe yes, it is still calibrated for a set speed.
There are no "limitations" with the duet 2 board as far as I'm aware except memory is a bit tight.
and IS is applied to all moves in 3.6 whereas its only applied to a small number of moves in 3.5.2 and under

[jay_s_uk]

@o_lampe and I should add I've tried 3.6 at various speeds and the ringing is a lot less when compared to 3.5 and under.
Also PA has been improved dramatically in 3.6

[o_lampe]

@jay_s_uk For the time being, it would probably be good enough to have two IS calibrations and manually switch between them.
IIRC I can't use all the possible IS algos with Duet2? Using EI3 would probably cover enough frequencies for eg.100mm/s and 150mm/s printspeed?

@all Does anyone use PS max. volumetric speed feature?

[jay_s_uk]

@o_lampe I'm not aware of any limitations regarding which IS algorithms can be used with the Duet 2.

[dc42]

@o_lampe if you find you need different input shaping depending on speed, something is wrong. It's possible that you have two resonances and different speeds tend to excite one or the other; but I think this is unlikely. More likely is that what you think is a resonance is actually vibration caused by the belt teeth cogging, and that will of course vary with speed.

[o_lampe]

@dc42 I don't use an accelerometer to tune IS, but the caliper method.
I've now switched from ZVD to EI3 and do some test prints.
IMHO belt teeth cogging would have a much higher resonance, more like VFR-artifacts?