[BUG] Y-Axis Motor Shake with ZV Input Shaping Enabled Only on Y-Axis

[johnnychang924]

Did you test the latest bugfix-2.1.x code?

Yes, and the problem still exists.

Bug Description

When ZV input shaping is enabled only on the Y-axis (with the X-axis shaping disabled), the Y-axis motor experiences strong shaking and skips steps during movement. The issue does not occur when input shaping is enabled on both axes or when it is completely disabled.

Bug Timeline

new bug

Expected behavior

Smooth motion of the Y-axis with accurate positioning when input shaping is applied only to the Y-axis.

Actual behavior

The Y-axis motor shakes violently and skips steps, resulting in significant inaccuracies in positioning. This makes the printer unusable.

Steps to Reproduce

1. Configure Marlin firmware to enable ZV input shaping only on the Y-axis: INPUT_SHAPING_X_AXIS disabled INPUT_SHAPING_Y_AXIS enabled

2. Start any movement or home the printer.

Version of Marlin Firmware

2.1.2.4

Printer model

Ender-3 Pro with switchwire mod

Electronics

creality 4.2.2

LCD/Controller

cr-10 stock

Other add-ons

I use stock extruder motor as y-axis motor.

Bed Leveling

UBL Bilinear mesh

Your Slicer

Cura

Host Software

SD Card (headless)

Don't forget to include

• [X] A ZIP file containing your Configuration.h and Configuration_adv.h.

Additional information & file uploads

I am using a CoreXZ 3D printer, and in Marlin, CoreXZ configurations do not support input shaping on the X-axis. Therefore, I need to use input shaping only on the Y-axis. Configuration.zip

[SMH17]

I'm facing this critical issue too, and mostly the shift happens on Y axis although some prints show problem on X at same time, but it happens with input shaping enabled on both axes. So, I think that your claim about the issue not occurring when enabled on both X and Y axis could be just by coincidence.

It seems working normal then suddenly it goes crazy: a stepper rattling noise with a shift of bed to a significantly higher than normal Y position, continuing to print "normally" in a then heavily misaligned position behind the correct layer alignment, without any gradual shifting till the next recurrence of the problem.

• The problem represents itself also with low print speed and without mechanical problems as loose belts etc.
• Reducing or bumping stepper voltage doesn't seem to have any effect on the frequency of the issue.
• Enabling or disabling S_CURVE_ACCELERATION doesn't affect the issue too.

I haven't tried disabling STEALTHCHOP yet, that is the next in my list of suspect co-factors.

I have seen many issues related to shifting that are closed due to inactivity, without any related fix, I think the autoclosing of issues like this should be prevented till a proper determining of the cause of the problem and fix, otherwise these remains hidden and not properly addressed.

EDIT Reproduced exactly the same issue also with input shaping totally disabled, the issue in my case is this.

[johnnychang924]

Thank you for your reply! It seems like we're experiencing different issues. In my case, the machine works perfectly fine when input shaping is completely disabled, with no step skipping or vibrations on any axis. The problem only arises when ZV input shaping is enabled exclusively on the Y-axis. This contrasts with what you're describing, where you encounter the issue even with input shaping disabled.