inputshaping on IDEX?

sebkritikel

M204 P20000 T20000 ; Set print and travel acceleration maximums

How did you calculate these acceleration values (or at least pick them)?

Have you tried something a little simpler than a benchy? I like the ringing tower test as it gives you a chance to test X and Y. A little simpler to start there - quick prints, easier to see the results from changing input shaping values, jerk values, speeds, etc.

oliof

@sebkritikel I tried simpler things and they have similar issues.

also, the M204 is just a maximum value that I set to a (high) limit. I am not using acceleration control from the slicer, so the acceleration values from the line before M204 are being used

M201 X7500.00 Y4000.00 U7500.00 Z100.00 E6000.00     ; Set accelerations (mm/s^2)

sebkritikel

@oliof Ah totally missed that line!

Is the ringing worse in a specific single axis direction (noticeably worse in X vs Y)? Input shaping working better on a single axis?

MaxGyver

I have had similar motor-vibration issues with RRF 3.5b2 on my IDEX. -> Forum Post and Video

In my case, print speeds between 30mm/s to 100mm/s produced horrible resonance in the motors. Switching the firmware back to stable helped. Unfortunately, I did not have the time and patience to investigate the cause further.

oliof

@MaxGyver unfortunately, switching back isnt really viable with the 2040 toolboards.

oliof

@sebkritikel I will print the standard ringing tower in a hot minute, maybe that will shed some light.

oliof

on my particular machine with the Klipper test print I see the same ringing at my accelerations, as well as reducing X down to 4000mm/sec^2. The frequencies I measure are pretty low (about 20 Hz) ... I assume on the smaller benchy the repeating pattern double up. My best bet is that this is due to the shoddy table. I am not sure that Input Shaping can deal with frequencies this low.

oliof

@sebkritikel I did reduce accelerations to 3k on both X and Y and I am still getting ringing artefacts at roughly 3mm frequency with and without IS (100mm/sec print time still). With 3.5-beta.3 there are some other issues when using IS that I need to investigate further. Not sure if this is IDEX related, or just my machine exhibiting bad ringing from a source IS can't do anything about.

sebkritikel

@oliof My IDEX gantry is fairly heavy - a few kilograms, so I typically run my print moves at 1000 mm/sec^2, and my travel moves at 4000 mm/sec^2 (I do outer walls/perimeters from 45mm/s to 120mm/s, and right now travels at 450mm/s - 600mm/s).

I previously calculated 4000 mm/sec^2 as the max safe acceleration value for the X-U gantry (weight/motor torque, etc), and while I did see substantial improvements with input shaping at that acceleration, I still had (IMO) unacceptable acceleration induced ringing. I settled on 1000 mm/sec^2 based on test prints and measured data from the shaping plugin.

20hz does seem really, really low - reminds me when a bearing block mounting screws were a touch too long, so the mounting plate could actually rotate slightly on direction changes. Once I noticed that, I was able to eliminate that frequency from the input shaping charts, and focus (and reduce) the 49hz band (or frequencies around that, I believe I split the distance to hit two frequencies (X and Y)) with EI3.

oliof

@sebkritikel my individual IDEX heads are pretty light (two EVA toolheads, can run 20k and more acceleration on other machines) and only run in X (its still an i3 style bed slinger), so I think I am good on the weight front.

I guess I need to actually put an accelerometer on mine since the Klipper test print shows almost nothing in terms of ringing. if that gives me weird graphs, I will go hunt for things that move when they shouldn't.