Issue with X-Axis on Enders 3 v2

General Discussion
1

Heyho,

i got a new problem that i am not able to fix myself and hope you guys have an idea or a fix.

I am running Klipper on my Ender 3 v2 i nearly modified everything and it works realy good, with very smooth quality prints. If you don’t measure them :slight_smile:

If i do the cali_cube (just as an example) it’s exactly 20.20x20.00x20.00 ± 0.02 depenting on filament and how serious i calibrated the flow/temp etc. anyways, absolute same results on every print.

But there is my Problem X is always moving too big/long. Even on non print movements it moves 10.10 instead of 10. If i measure with a caliper on every +10mm move it’s +10.10mm (even on 1mm it’s 1.01). Also if i travel 100mm in one go, it’s mostly perfect 101mm in real (± 0.02, but mostly exactly 101.00).

What i tried so far: Replaced wheels on carrier. Replaced belt. Replaced Stepper motor and exchanged pulley too with a similar (20T). Tried 1.8° and 0.9° stepper. Tried SKEW Correction, i am measuring the issue i am facing in 3 diffent skew calibration objects i printed so far, but if i enter the values and let him print again, it has no impact on X as it should have (what means it’s 20.15-20.17, what is an improvement, but yeah … not what i got on all of my other printers - for sure it’s deactivated while not printing as mentioned in Klipper documentation). Even tighten or loosen the belt doesn’t realy impact the outcome, sure in both directions is a point that other problems occure like slipping belt etc., but as long as he mechanical can, it’s as mentioned above.

At the moment X and Y do have the same stepper motors pulleys and belts, with any issues on Y, so i quote down my config for them below - Board is SKR E3 Mini v3:

[stepper_x]
step_pin: PB13
dir_pin: !PB12
enable_pin: !PB14
microsteps: 16
rotation_distance: 40
full_steps_per_rotation: 400
endstop_pin: ^PC0
position_endstop: -13
position_min: -13
position_max: 247
homing_speed: 50

[tmc2209 stepper_x]
uart_pin: PC11
tx_pin: PC10
uart_address: 0
interpolate: True
run_current: 0.950
hold_current: 0.570
sense_resistor: 0.110
stealthchop_threshold: 999999

[stepper_y]
step_pin: PB10
dir_pin: PB2
enable_pin: !PB11
microsteps: 16
full_steps_per_rotation: 400
rotation_distance: 40
endstop_pin: ^PC1
position_endstop: -32.5
position_min: -32.5
position_max: 222
homing_speed: 50

[tmc2209 stepper_y]
uart_pin: PC11
tx_pin: PC10
uart_address: 2
interpolate: True
run_current: 1.000
hold_current: 0.600
sense_resistor: 0.110
stealthchop_threshold: 999999

Thanks and Regards,
MBPM

2

i believe u can correct it with the rotation distance.

https://www.klipper3d.org/Rotation_Distance.html

rotation_distance = <previous_rotation_distance> * <actual_extrude_distance> / <requested_extrude_distance>

so if we fill this in: new rotation distance = 40 * 10.10 / 10 = 40.4 this should be your new x rotation distance

1 Like
3

Hey,

thanks for the reply. I am aware of it, but i lived since a few years now in the knowledge if you have to correct your steps, something is wrong :slight_smile: and other issues will occure, so correct me if i am wrong - but shouldn’t this be only the last possible solution for my problem ? (i don’t know it better)

Thanks and Regards,
MBPM

4

might also be tollerance issue in the motors or name it. small tollerances will add up and boem your problem. i read somewhere that cheap chinees motors can have this issue. i wouldnt bother that much if i were u. atleast your error on position is very consistant, making it easy to adjust using rotation distance

5

Actually correcting the rotation_distance is the recommended way for Klipper to ensure accuracy.

https://www.klipper3d.org/Rotation_Distance.html

Keep in mind, that if the printer has a decent time of print in it’s life, there is wear.
Mostly in the belts.
Also the pulleys can be out of dimension. We are talking about a misalignment of 1%.

Technically my printer also should have a rotation_distance of 40 for X and Y, but it’s running with 39.84 to be accurate.

6

Hi,

thanks for the replies and i guess you are right that i bother to much about that. But unfortunatelly i changed the rotation distance as mentioned by jules and the movement distance is now very inconsistant 10 ± 0.15. Edit: and once went back to previous settings it’s massivly consistant again, but still the 0.1 too much on 10mm.

There is no wear on the machine, it’s a brand new Ender 3 v2 from a summer sale and i also exchanged most of the possible parts after facing the issue. Only the stepper motors where some i got laying around since a while, but StepperOnline ones (no issues with them in the last years on my other printers, as i use them in all of them - for sure not the best and pricy for what you get, but good available here and better then most nonames). But who knows maybe i tried 2 worn out stepper motors or there is something wrong with the cable, i will exchange it tomorrow with brand new ones and report it here.

So far thanks for help, highly appreciated.

Regards,
MBPM