Solved [3.4beta6] CoreXY 'Banging' Motor Sound

[Pakue]

After updating I've noticed a very loud motor 'banging' sound when changing direction, similar to having the acceleration/jerk set very high. The issue happens even with low jerk/acceleration/feed setting.

Here a video of the noise while running with these settings:

• M556: X: 600.0, Y: 600.0, Z: 50.0, E: 600.0, jerk policy: 0
• M204: Maximum printing acceleration 50.0, maximum travel acceleration 200.0 mm/sec^2
• Feed: 10000

https://youtu.be/N-n4tybucY4

config.g

G4 S1   ;wait for expansion boards to start
; General preferences
G90                                          ; send absolute coordinates...
M83                                          ; ...but relative extruder moves
M550 P"Duet 3"                               ; set printer name
M669 K1                                      ; select CoreXY mode

; Drives
M569 P20.0 S0                                ; toolboard drive 0.0 goes forwards 
M569 P0.1 S1 D3 H49 V49                      ; physical drive 0.1 goes forwards
M569 P0.2 S0 D3 H49 V49                      ; physical drive 0.2 goes forwards
M569 P0.3 S1                                 ; physical drive 0.3 goes forwards
M569 P0.4 S1                                 ; physical drive 0.4 goes forwards
M569 P0.5 S1                                 ; physical drive 0.5 goes forwards
M584 X0.2 Y0.1 Z0.3:4:5 E20.0                ; set drive mapping
M350 X16 Y16 Z16 E16 I1                      ; configure microstepping with interpolation
M92 X80.00 Y80.00 Z1600.00 E655              ; set steps per mm
M566 X1000.00 Y1000.00 Z50.00 E600.00 P1     ; set maximum instantaneous speed changes (mm/min)
M203 X60000.00 Y60000.00 Z400.00 E3600.00    ; set maximum speeds (mm/min)
M201 X10000.00 Y10000.00 Z80.00 E600.00      ; set accelerations (mm/s^2)
M906 X1600 Y1600 Z800 E450 I30               ; set motor currents (mA) and motor idle factor in per cent
M84 S30                                      ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z0 S1                             ; set axis minima
M208 X300 Y250 Z200 S0                       ; set axis maxima

; Endstops
M574 X1 S3                                   ; configure sensorless endstop for low end on X
M574 Y1 S3                                   ; configure sensorless endstop for low end on Y
M574 Z1 S2                                   ; configure Z-probe endstop for low end on Z
M915 X Y R0 F0 S3 H200 	                     ; enable sensorless homing

; Z-Probe
M558 P9 C"20.io0.in" H3 F200 T15000 A4 S0.02    ; set Z probe type to bltouch and the dive height + speeds
M950 S0 C"20.io0.out"
G31 X0 Y-20.0 Z3.10 P25                        ; set Z probe trigger value, offset and trigger height
M671 X-8:295:144 Y-15:-15:290 S10             ; leadscrews at front left, front right and rear middle
M557 X10:290 Y0:230 P4:4                    ; define mesh grid

; Heaters
M308 S0 P"temp0" Y"thermistor" T100000 B4138 ; configure sensor 0 as thermistor on pin temp0
M950 H0 C"out0" T0                           ; create bed heater output on out0 and map it to sensor 0
M307 H0 B0 S1.00                             ; disable bang-bang mode for the bed heater and set PWM limit
M140 H0                                      ; map heated bed to heater 0
M143 H0 S120                                 ; set temperature limit for heater 0 to 120C
M308 S1 P"20.temp0" Y"pt1000"                   ; configure sensor 1 as PT1000 on pin temp1
M950 H1 C"20.out0" T1                           ; create nozzle heater output on out1 and map it to sensor 1
;M307 H1 B0 S1.00                             ; disable bang-bang mode for heater  and set PWM limit

; Fans
M950 F0 C"out1" Q1000                           ; create fan 0 on pin out7 and set its frequency
M106 P0 S0 H-1                               ; set fan 0 value. Thermostatic control is turned off
M950 F1 C"out2" Q1000                           ; create fan 1 on pin out8 and set its frequency
M106 P1 S1 H1 T50                            ; set fan 1 value. Thermostatic control is turned on

; Tools
M563 P0 D0 H1 F0                             ; define tool 0
G10 P0 X0 Y0 Z0                              ; set tool 0 axis offsets
G10 P0 R0 S0                                 ; set initial tool 0 active and standby temperatures to 0C

; Accelerometer
M955 P20.0 I20								 ; Acc. on tool board CAN 20 with orientation 20

; Miscellaneous
M501                                         ; load saved parameters from non-volatile memory
T0   

[mrehorstdmd]

Do all the obvious stuff first- make sure everything is bolted down tightly, make sure the drive pulleys are tight on the motor shafts, make sure the X axis assembly is tight on the Y axis bearing blocks, make sure the belts are tight (but not too tight).

[64bit]

Your maximum speeds are 1000mm/s? Id love to see that thing printing. 10,000 accel is pretty crazy IMHO too.

[Pakue]

@mrehorstdmd Seems like I'm having the same issue with stealthchop like in this issue: https://forum.duet3d.com/topic/25593/problem-with-proper-setting-of-stealthchop-to-spreadcycle-mode
Setting the drivers to spread cycle only fixed the issue. I'm a bit confused why the problem only appeared with the recent beta (didn't run beta 5 though).

[Pakue]

@64bit I don't run it nearly as fast usually, that's just what the motion system can do. Having the filament lay down nicely at that speed is a bit harder (never mind the noise... :D).

[dc42]

@pakue you are running the drivers in stealthChop mode. A jerk or bang is normal when switching between stealthChop and spreadCycle modes at high speed. There are two ways round this:

1. Set the changeover speed much lower, so that the bang will be much less.
2. Reduce the maximum speed, so that you can run in stealthChop mode right up to that speed.

[Pakue]

@dc42 Thank you for the answer! I found running it only in spread cycle the best option for this setup.