Question Step Loss on stepper_X

[josephF]

I have a weird problem on my Voron 2.4.

I often get huge layer shifts on very random files. To determine the origin of the problem, I ran a speed test with various acceleration and speed values, from 0.5k to 2k and 100 to 400 mm/s.

At the time I ran the tests, any acceleration above 2k sounded bad and showed direct step losses, so I reduced it to 2k and 300 mm/s, and there are no more step losses during tool head acceleration.

However, I systematically get about 6 mm (aka 1200 step losses) on my speed tests, and only on the X stepper, with exactly the same numbers each time!

// mcu: stepper_x:-1315 stepper_y:245 stepper_z:23 stepper_z1:-79 stepper_z2:1541 stepper_z3:-22
// stepper: stepper_x:583.975000 stepper_y:0.000000 stepper_z:10.000000 stepper_z1:10.000000 stepper_z2:10.000000 stepper_z3:10.000000
// kinematic: X:291.987500 Y:291.987500 Z:10.000000
// toolhead: X:299.000000 Y:299.000000 Z:10.000000 E:0.000000
// gcode: X:299.000000 Y:299.000000 Z:10.000000 E:0.000000
// gcode base: X:0.000000 Y:0.000000 Z:0.000000 E:0.000000
// gcode homing: X:0.000000 Y:0.000000 Z:0.000000
23:30
// mcu: stepper_x:-34 stepper_y:248 stepper_z:22 stepper_z1:-80 stepper_z2:1540 stepper_z3:-23
// stepper: stepper_x:600.012500 stepper_y:0.012500 stepper_z:10.000000 stepper_z1:10.000000 stepper_z2:10.000000 stepper_z3:10.000000
// kinematic: X:300.012500 Y:300.000000 Z:10.000000
// toolhead: X:299.000000 Y:299.000000 Z:10.000000 E:0.000000
// gcode: X:299.000000 Y:299.000000 Z:10.000000 E:0.000000
// gcode base: X:0.000000 Y:0.000000 Z:0.000000 E:0.000000
// gcode homing: X:0.000000 Y:0.000000 Z:0.000000

I swapped every thing related to the stepper_x motion :
motor
cable
driver
motherboard motor plug
I also checked the motion of the gantry, which is buttery smooth; my belt tension also seems good. I really don’t know where to look to solve this problem!

Thank you for your help.
Joseph

 

[NoGuru]

Can we see the printer.CFG with the X motor sections.

 

[josephF]

#####################################################################
#   X/Y Stepper Settings
#####################################################################

##  B Stepper - Left
##  Connected to MOTOR_0
##  Endstop connected to DIAG_0
[stepper_x]
step_pin: PE6 #PF13
dir_pin: PA14 #PF12
enable_pin: !PE0 #!PF14
rotation_distance: 40
microsteps: 16
full_steps_per_rotation:200  #set to 400 for 0.9 degree stepper
endstop_pin: EBBCan: PB6
position_min: 0

##--------------------------------------------------------------------

##  Uncomment below for 250mm build
#position_endstop: 250
#position_max: 250

##  Uncomment for 300mm build
position_endstop: 300
position_max: 300

##  Uncomment for 350mm build
#position_endstop: 350
#position_max: 350

##--------------------------------------------------------------------
homing_speed: 50   #Max 100
homing_retract_dist: 5
homing_positive_dir: true
##  Make sure to update below for your relevant driver (2208 or 2209)
[tmc2209 stepper_x]
uart_pin: PD3 #PC4
interpolate: false
run_current: 1
sense_resistor: 0.110
stealthchop_threshold: 0

##  A Stepper - Right
##  Connected to MOTOR_1
##  Endstop connected to DIAG_1
[stepper_y]
step_pin: PG0
dir_pin: PG1
enable_pin: !PF15
rotation_distance: 40
microsteps: 16
full_steps_per_rotation:200  #set to 400 for 0.9 degree stepper
endstop_pin: PG6
position_min: 0
##--------------------------------------------------------------------

##  Uncomment for 250mm build
#position_endstop: 250
#position_max: 250

##  Uncomment for 300mm build
position_endstop: 300
position_max: 300

##  Uncomment for 350mm build
#position_endstop: 350
#position_max: 350

##--------------------------------------------------------------------
homing_speed: 50  #Max 100
homing_retract_dist: 5
homing_positive_dir: true

##  Make sure to update below for your relevant driver (2208 or 2209)
[tmc2209 stepper_y]
uart_pin: PD11
interpolate: false
run_current: 1
sense_resistor: 0.110
stealthchop_threshold: 0

I put both X and Y stepper settings, Y stepper doesn't cause any issues. The commented values for the X stepper are those from driver 0. Since the actual printer.cfg file is testing driver 7 of the octopus v1.1 the values differ.

 

[NoGuru]

The only deviation from a standard config that I see is your run current is set to 1 instead of .8 and you are running 16 micro steps instead of 32.
Neither one should be an issue but might be worth setting them back just to test.
Maybe your steppers are overheating. See if you can run with a fan on them.
If none of this works, replace them with better drivers like 2240's or whatever the latest ones are.

 

[josephF]

Thank you for your advice. The standard settings did not work either. I changed them to try to provide a bit more torque to the motor, but that did not help.

Also, overheating is not probable because I ran the speed tests on a cold machine, and the motors are not even warm to the touch after the test.

I will try to replace the drivers, but having the issue move with different drivers or motor positions on the motherboard seems odd to me.

 

[endstop]

Have you checked whether your slicer overrides the printer.cfg values?
This has happened to me with Orcaslicer, for example the extrusion multiplier test would cause XY skips every time.
With default settings, large speed values default to machine limits e.g. G1 X10 Y10 Z10 F999999 is safe on my printer. As long as the slicer doesn't mess this up...
Check the G-code.

 

[uwedamm]

What do you mean by x stepper?
I do know about A/B steppers on corexy printer.
My voron 2.4 sometimes lost steps for one of them (both made trouble, one at a time) due to issue with the connector on the Motor side. I replaced it by waago clamps, no issue since then.

 

[NoGuru]

Something else I just thought of, what is your belt tension at? How does it feel moving the toolhead around with the motors off? It should be fairly smooth and easy to move them in a square pattern.