Input Shaping driving me nuts

Exerqtor

Ok, so I've finally updated from RRF 3.50b1+ too 3.5.0b2 and sorted out the issues i was having regarding that and moved over to giving IS tuning a new go.

Lowered the jerk to 300mm/min as per @droftarts suggestion.

My printers movement config is as follows (350x350 corexy):

; Axis accelerations and speeds
M566 X300.00 Y300.00 Z30.00 P1                                                 ; Set maximum instantaneous speed changes (mm/min) and jerk policy (XY WAS 700)
M203 X18000.00 Y18000.00 Z900.00                                               ; Set maximum speeds (mm/min)
M201 X6000.00 Y6000.00 Z150.00                                                 ; Set accelerations (mm/s²)

; Extruder accelerations and speeds
M566 E8000.00 P1                                                               ; Set maximum instantaneous speed changes (mm/min) and jerk policy
M203 E15000.00                                                                 ; Set maximum speeds (mm/min)
M201 E1800.0                                                                   ; Set accelerations (mm/s²)

; Reduced accelerations
M201.1 X500 Y500 Z80 E500                                                      ; Set reduced acceleration for special move types (mm/s²)

The first test i tried finding the ideal M204 / printing acceleration. Both IS and PA turned off, starting with 500mm/s² stopping at 5000mm/s² in 500mm/s² increments @ 100mm/s print speed:
alt text

Judging by those result i think 3500mm/s² seems "ok", so i changed my config to:

M201 X4500.00 Y4500.00 Z150.00                                                 ; Set accelerations (mm/s²)
M204 P3500 T4500                                                               ; Set printing acceleration and travel accelerations (mm/s²)

Then let the print chamber heat ut to around 60-65C, so that everything is in the "state" where i normally do my prints. Hoping that the accelerometer outputs would be as close as possible to what a real life printing scenario would be.

Recorded two motion profiles with IS off and about 2min pause between them to let things settle:
Profile1
Profile2

With a 48Hz shaper center frequenzy, the plugin suggested ZVD:
Suggested shaper

I'm currently doing a new test print with the new accelerations settings, going thru all the shapers @ 48Hz. I'll post the results of that as soon as it finishes👀

Exerqtor

@Exerqtor
And the results:
alt text

IMO, the best result is ZVDDD. Even though it's not "perfect".

Al_Capwn

@Exerqtor Thank you very much for the effort and posting of your results.

Now for the question, what did you do to have the print broken down into different types of IS from EI3 to None? when it stops raining (too much humidity ) I'll set up and do the same to post my results and findings

Hoping that lowering the jerk gives me what I'm looking for

Exerqtor

@Al_Capwn
Np, hope it can help you a little bit.

I'm using Prusaslicer, so you have the option to incert custom g-code at what layer/height you wish.
So i add M593 commands manually with that each 5mm

Thought i should add that i'm going to run another test print @ 35Hz as well and see how that turns out. Since it's the Y-axis thats having the most visible ghosting that might be a better frequency for me to shape. I'll post the results tomorrow 🤟

Adamfilip

@Exerqtor I get this frustration. Im at the point where I want to stop tinkering so much to get my printer to just print "normally" Bambu machines are looking better and better lol

hestiahuang

@Adamfilip said in Input Shaping driving me nuts:

@Exerqtor I get this frustration. Im at the point where I want to stop tinkering so much to get my printer to just print "normally" Bambu machines are looking better and better lol

Bambu is Klipper base?

Adamfilip

@hestiahuang dont know. its a closed firmware

Al_Capwn

UPDATE:

Finally got around to trying things again now that there is a day of not rain, hail or near freezing temps.. only ran one test but it seems to have had large affect.

@droftarts , lowering the jerk seemed to do the trick, i have them down to 150/150, i'm only able to push it to 2000 m/s accel though including pictures

[link text]( link url)

alt text

Here is a picture of the much better looking (imo) input shaping and a picture of the final product, the second ring from the bottom is 2000m/s and after it goes up 500 about every ring, there is a huge change from 2000 to 2500 which seems odd to me and it goes as high as 7000m/s.

Anyway, tomorrow going to print (if its not raining) another set of speed tests to see if i can go faster then 50m/s in print speed, wish me luck and thanks all for the help ^_^ (Will post how that turns out as well, probably with another print for the voron to give a compare/contrast.

dc42

@Al_Capwn I'm glad you are getting better results now.

Large values of XY jerk do indeed reduce the effect of input shaping, so reducing XY jerk was the right thing to do. The main effect of low XY jerk is that curves that are made up of course segments will print more slowly.

Extruder jerk does not need to be reduced for input shaping, so it should be kept fairly high in order not to reduce acceleration when pressure advance is used.

You may also wish to try reducing the damping factor. I have a feeling that a damping factor of zero may be best when using the higher order input shapers, and the damping factor only really needs to be tuned when using the more basic shapers. On one of my printers, damping factor 0.0 certainly gives better results than 0.1.

Exerqtor

@Al_Capwn
Glad to see you getting some visible results! I've started testing with 150mm/min jerk today too.
Spewing out some test prints atm ✌

@dc42

Maybe it should be covered in the jerk documentation now that input shaping has become a thing.
What you just said would be valuable info for alot of us when we start tuning 😅

Exerqtor

Ok so in the quest to get this ghost into the proton pack I've and still being able to run high(ish) accelerations on most of the print WITHOUT using the PrusaSlicers built in acceleration control (I want to handle as much as possible in RRF) i think I've come up with a working solution.

By using regex in the PS G-code substitutions I'm now setting global.line_type to represent what kind of line/extrusion the printer is performing. Im doing this with Find: ^;TYPE:(.*) Replace with ;TYPE:$1\nset global.line_type = "$1".

Now that RRF know what's going on we have a bit more freedom to "manipulte" what happens. As of now i'm only changing what happens for External perimeters & Top solid infill since that's what we end up seeing anyways Ii'm also lowering the first layer acceleration, but that's for bed adhesion purposes).

The changes are done with daemon.g, who looks like this:

  ; Print acceleration & input shaping controll
  if global.accel_controll
    if global.layer_number = 1
      M204 P500                                                                ; Set printing acceleration(mm/s²)
    else
      if global.line_type = "External perimeter"
        if move.printingAcceleration != global.low_accel
          M204 P{global.low_accel}                                             ; Set printing acceleration(mm/s²)
        if move.shaping.type != global.input_shaper
          M593 P{global.input_shaper}                                          ; Configure input shaping
      elif global.line_type = "Top solid infill"
        if move.printingAcceleration != global.low_accel
          M204 P{global.low_accel}                                             ; Set printing acceleration(mm/s²)
      else
        if move.printingAcceleration != global.def_print_accel
          M204 P{global.def_print_accel}                                       ; Set printing acceleration(mm/s²)
        if move.shaping.type != "none"
          M593 P"none"                                                         ; Disable input shaping

The globals referenced in daemon.g get set in globals.g at startup and look like this:

if !exists(global.input_shaper)
  global input_shaper = (move.shaping.type)

if !exists(global.def_print_accel)
  global def_print_accel = (move.printingAcceleration)

if !exists(global.low_accel)
  global low_accel = 1500

if !exists(global.accel_controll)
  global accel_controll = true

if !exists(global.line_type)
  global line_type = "N/A"

if !exists(global.layer_number)
  global layer_number = 0

global.layer_number is also set automatically by PS by the "After layer change G-code" seciton with set global.layer_number = {layer_num+1}

Note that everything else is set like usual in config.g except global,low_accel,

Haven't gotten time to do more any test prints yet, only some preliminary 2-3minute test's to see that the code works.

Anyhow this should allow us to bump up the accelerations for everything that's not visible in the finished print without relying on the slicer doing the "right" thing.

droftarts

@Exerqtor said in Input Shaping driving me nuts:

@dc42

Maybe it should be covered in the jerk documentation now that input shaping has become a thing.
What you just said would be valuable info for alot of us when we start tuning 😅

Yes, we've been discussing this. I'll update the documentation next chance I get.

Ian

Exerqtor

@droftarts said in Input Shaping driving me nuts:

@Exerqtor said in Input Shaping driving me nuts:

@dc42

Maybe it should be covered in the jerk documentation now that input shaping has become a thing.
What you just said would be valuable info for alot of us when we start tuning 😅

Yes, we've been discussing this. I'll update the documentation next chance I get.

Ian

Glad to hear!

Out of curiosity, if we take a look at this motion analysis:
alt text

What would be the best shaper center frequency? My logic wants me to put it somewhere in the middle of the X / Y spikes at 39Hz, is that reasonable? Putting it at the X-axis peak / highest frequency totally smooth's out one axis (like one would suspect), but leaves something to be desired on the other in the test prints.

sebkritikel

@Exerqtor said in Input Shaping driving me nuts:

What would be the best shaper center frequency? My logic wants me to put it somewhere in the middle of the X / Y spikes at 39Hz, is that reasonable? Putting it at the X-axis peak / highest frequency totally smooth's out one axis (like one would suspect), but leaves something to be desired on the other in the test prints.

This is a totally reasonable approach, and one I've seen recommended a few times. Some shapers have a failry broad range, and can address two (or more ringing frequencies).

In the left column, tick 'estimate shaper effect' and then the 'show original values option'. Move your mouse over to the right, and click in the 'shaper centre frequency' after selecting a shaper. You can then scroll through the frequencies with your mouse wheel, and see how the frequency and damping factors change the results.

Exerqtor

@sebkritikel
Okok, nice to get confirmation that my brain works from time to time😅

Yeah i've tried playing around with those estimated values, but in my case they haven't really been representative of what ends up happening once i do a testprint.

I'm doing a testprint with zvd-ei3 @39Hz with zero dampening to see how it turns out.

On another tangent though, what M204 P value we have does effect the motion analysis right? Those still get applied on the test moves?
I haven't seen any mention of it in the documentation, but i would assume it gets applied.

OH YEAH! One more thing, does the Shaper center frequency support/allow for decimal numbers?🤔

sebkritikel

@Exerqtor M204 question is a good one (and unfortunately I don't know the answer), may be a good note that gets added to the documentation.

I just tried a decimal value for the shaper frequency, and it seemed perfectly happy to report it back to me.

Input shaping 'ei3' at 49.5Hz damping factor 0.10, min. acceleration 10.0, impulses 0.221 0.498 0.758 0.925 with durations (ms) 10.97 9.90 9.70 9.69

To be honest though, I can't imaging you wold need that extra significant digit for your shaper frequency.

Al_Capwn

@dc42 Hello and thank you for your time,

I have been... WAY busy with work so the past few days has been work, sleep, mess with 3d printer, work, sleep >_<; Only now reading through the thread.

I have done a LAWT and have a question for you @dc42 if you would, what amount of acceleration Should I set for the extruder if my X/Y acceleration is set to 7000? I currently have it set to 1500 and have not seen issues.

Ok, now for the BIG UPDATE

To all of those still watching here, and sorry again for not posting in a few days... I have finally gotten to a stable/workable slicer profile/printer settings etc. as far as jerk goes.. The old print was with input shaping and zero jerk where the new is 14 jerk for the walls and 10 for the top/bottom.

alt text

Ran out of filament when printing this one and had to start on a roll that was a little waterlogged.
alt text

alt text

if you want to see the rest here is the galley https://imgur.com/a/6oXPUVE

I will try out lowering my damping factor a little bit later and report on how that goes, later tonight or tomorrow and report on the results with pictures probably.

Thank/thanks again all who showed interest and/or offered assistance/advice, it was welcome/apricated

dc42

@Exerqtor said in Input Shaping driving me nuts:

What would be the best shaper center frequency? My logic wants me to put it somewhere in the middle of the X / Y spikes at 39Hz, is that reasonable?

From that graph it looks to me that you need to cancel about 25Hz to 52Hz. The Input Shaping plugin will allow you to select a shaper type and centre frequency, and overlay on the graph the effect of the shaper. The frequency range is about 2:1 so a ZVDD or EI2 shaper may be sufficient.

Al_Capwn

@dc42 hello again and sorry for pinging you again,

As well as the question about acceleration, what max jerk should I have my printer set to? Continuing to tune my printer and noted something strange. I have a bondtech BMG, when I first started to dial things in and set up linear advance I noticed a strange, not quite grinding sound that had popped up, apparently this is just a thing with dual gear extruders (or at least my googling told me.)

Ok, now for the strange, I had forgotten about this because at some point I had turned down my extruder jerk down to 300, switching it back to 900 has caused the not quite grinding sound to come back. SO, if 300 jerk is fine I would leave it there just to save on noise pollution, otherwise, if 900 or greater jerk is the best way to go I'll deal with the added sound.

Thank you again ^_^

Exerqtor

@dc42 said in Input Shaping driving me nuts:

From that graph it looks to me that you need to cancel about 25Hz to 52Hz. The Input Shaping plugin will allow you to select a shaper type and centre frequency, and overlay on the graph the effect of the shaper. The frequency range is about 2:1 so a ZVDD or EI2 shaper may be sufficient.

Aha i thought one should base on the peaks not where the peaks "start/stop" to climb/fall. I've adjusted the center frequency to 38.5Hz and ZVDD now to see i if i can see a noticable difference on a print i just ran with 41,8Hz & EI2.