3.5.0rc1 Input Shaping Layer Shifts not addressed in 3.5.0rc2

dc42

@bulbs yes I've fixed an issue in RC1 that could case layer shifts. It's the same issue that caused one of the filament monitor issues.

NeoDue

@gloomyandy If I may, I also posted this issue (if there was a previous topic, I did not see it - please feel free to merge the threads): https://forum.duet3d.com/topic/33926/3-5-0rc1-input-shaping-causes-layer-shifts/

I will check after christmas if the change from dc42 in RC2 helps in my case.
(edit: seems RC2 was withdrawn - at least I do not see it on Github?)

dc42

@NeoDue rc2 hasn't been released yet. We expect to release it tomorrow.

tas

@dc42 I tried 3.5.0rc2 on my Duet2Wifi standalone.

The part printed perfectly up to 5mm then began a very slight shift (0.1mm per layer maybe) towards the origin in the Y axis only.

There were no collisions of the printhead and part and no errors generated. The part finished printing ok except for the shift.

Input shaping was enabled with
M593 P"zvdd" F45.7 S0.0 L100;

As well as pressure advance with
M572 D0 S0.0825

Jerk set to 300 in X and Y.

Printing speed was 50mm/s max on a heavily modified Ender 5 Pro, direct drive LGX Lite with E3D V6 and E3D 0.9 steppers.

Hopefully this info will help isolate the problem.

oliof

@tas M593 L parameter changed in RC2, and may need adjustment.

gloomyandy

@oliof Yes it looks like L is now a value between 0.01 and1.0 which is used to control how much the speed and acceleration of a move can be adjusted to allow input shaping to be applied. The default setting is 0.25.

The docs do not seem to have been updated yet though (one for @droftarts ?).

tas

@oliof And that is why I should always read about the changes. I will do some more testing today if I get time. Thanks.

tas

@oliof @gloomyandy
I changed L parameter value to the default of 0.25 and the problem is completely gone. No Y shifting at all.

Many thanks, that was an easy fix.

tas

@tas Well I posted too soon. The first part on the bed printed perfectly.

The second part had a single shift at about 7.5mm layer height and another at about 10mm. Each time it shifted it moved towards the Y origin by 0.3mm this time. A larger shift than before but much less often.

I will try turning off Input Shaping to confirm that is actually the problem.

tas

@oliof @gloomyandy
I tried the same gcode with Input Shaping disabled and there were no issues with the print so something is up.

gloomyandy

@tas What motor current are you using on your Y stepper? I wonder if increasing it would allow your print to work with IS enabled. It may be that if the current is "marginal" using IS is pushing things over the edge.

tas

@gloomyandy
That is a good point.

I like my motors to run cool. I run the X axis with the E3D 'Compact but powerful motor' (40mm) and Y axis with the E3D 'High Torque Motor' (48mm). The rated current is 1.68A max for both so 85% is 1.428A and I am only at half of that.

M906 X700 Y700 Z800 E300 I30 ;

If you would like a test done let me know but it won't be tonight.

I didn't have issues with Y shifting until this rc2 release though.

gloomyandy

@tas I would say it is worth running a test with a higher current to the steppers, but perhaps @dc42 would like to comment. The way that IS is applied was changed in rc1 and so it is likely that it is now being used on a greater set of moves.

Exerqtor

@tas Like @gloomyandy said, just for troublesbooting purposes try setting the current high. Try with 1400milliamps just for one print and check if it makes a difference.

tas

@Exerqtor @gloomyandy

M906 X1400 Y1400 Z800 E300 I30;

M593 P"zvdd" F45.7 S0.0 L0.25;

Test print running now.

tas

@Exerqtor @gloomyandy

The test print worked perfectly.

So the Y shifts were due to a configuration error on my part. The motors do need more current to meet the demands of input shaping.

The motors got a bit hotter than I would like by the end of the print but most people would call them warm so that is interesting for me. I will bump up the current in my configs.

Thank you both for the suggestions.

dc42

@tas with input shaping enabled, do the motors sound normal? I get a slight clunking sound when some types of IS are enabled on one of my machines. However, as the IS code is being rewritten I decided not to investigate this before releasing RC2.

You might like to run M122 after doing one of these prints. It has a new field that lists the maximum number of overdue steps encountered, and that may be related.

tas

@dc42 I can't say I noticed a noise difference but I will do some testing today and report back.

tas

@dc42
I did a test 'print' without filament using the Klipper ringing part in vase mode at 100mm/s. I tried none, zvd, zvdd, zvddd and with IS off.

The noise sounded 'silkier' with IS enabled and to my ear is the same no matter which type was used.

I did not hear any clunks, clicks or other unusual noises. The highest value for max steps late was 1. I hope that is the new value you are referring to.

Using a speed of 100mm/s I tried all Input Shapers starting with IS disabled. I did M122 at random times during each 'print' to get the following info.

No IS:
M122 Move:
DMs created 83, segments created 9, maxWait 1020ms, bed compensation in use: none, height map offset 0.000, max steps late 1, ebfmin -0.89, ebfmax 0.98
next step interrupt due in 28 ticks, disabled
Moves shaped first try 0, on retry 0, too short 0, wrong shape 0, maybepossible 0

IS "zvd":
M122 Move:
DMs created 83, segments created 22, maxWait 881ms, bed compensation in use: none, height map offset 0.000, max steps late 1, ebfmin -0.79, ebfmax 0.98
next step interrupt due in 6 ticks, disabled
Moves shaped first try 34, on retry 18, too short 63, wrong shape 4, maybepossible 1

IS "zvdd":
M122 Move:
DMs created 83, segments created 33, maxWait 17471ms, bed compensation in use: none, height map offset 0.000, max steps late 1, ebfmin -0.97, ebfmax 0.99
next step interrupt due in 49 ticks, disabled
Moves shaped first try 73, on retry 25, too short 112, wrong shape 9, maybepossible 0

IS "zvddd":
M122 Move:
DMs created 83, segments created 38, maxWait 2364ms, bed compensation in use: none, height map offset 0.000, max steps late 1, ebfmin -0.95, ebfmax 1.00
next step interrupt due in 12 ticks, disabled
Moves shaped first try 114, on retry 65, too short 189, wrong shape 20, maybepossible 0

Let me know if you need any other info or other tests done and I can do them later today.

edsped

@dc42 said in 3.5.0rc1 Input Shaping Layer Shifts not addressed in 3.5.0rc2:

@tas with input shaping enabled, do the motors sound normal? I get a slight clunking sound when some types of IS are enabled on one of my machines. However, as the IS code is being rewritten I decided not to investigate this before releasing RC2.

You might like to run M122 after doing one of these prints. It has a new field that lists the maximum number of overdue steps encountered, and that may be related.

With RC2 I get clunking bad enough that it causes layer shifts. I would get slight clunks on RC1 but RC2 is a whole other level... I'm to the point that I'm starting to try to figure out how to get back to RC1 with SBC. I can't downgrade to stable because I'm running RRF-36's. ZVD seems to be the mildest for me and ZVDDD is just plain awful.