Mesh bed leveling isn't working properly

[MrHradaa22]

Hello,

I've built a toolchanging 3D printer and I'm having issues with bed leveling. Using 3-point true bed leveling (G32) works just fine and it is consistant, however when I use standart mesh grid compensation these values aren't right. I have measured the compensation with dial indicator and in X axis it is about right but when I move from Ymin to Ymax (0-500) it linearly decreases 0,2 mm. I'm trying to figure it for quite some hours now.I thought it must be some kind of mechanical problem, but everything is solid. I have set correctly all offsets so when I'm probing (without tool) the probe is right in the middle of the bed and when I took any tool and move it to midle it is in the same spot. I'm using Duet 2 Wifi with dueX5, firmware 3.4.6.

Here is my config.g

; General preferences
M111 S0 						; Debugging off
G21 							; Work in millimetres
G90 							; Send absolute coordinates...
M83 							; ...but relative extruder moves
M555 P2 						; Set firmware compatibility to look like Marlin
M669 K1  ;X1:-1:0 Y1:1:0 Z0:0:1


; Network
M550 P"ToolChanger Salamander" 			; Set machine name
;M587 S"ssid" P"password"		; WiFi Settings
;M552 S1 P"ssid"				; Enable WiFi Networking
M552 S1							; Enable Networking
M586 P0 S1 						; Enable HTTP
M586 P1 S0 						; Disable FTP
M586 P2 S0 						; Disable Telnet

; Drive direction
M569 P0 S0 						; Drive 0 X
M569 P1 S1 						; Drive 1 Y
M569 P2 S0 						; Drive 2 Z1
M569 P3 S0 						; Drive 3 Z2
M569 P4 S1 						; Drive 4 Z3
M569 P5 S1 						; Drive 5 E1
M569 P6 S1 						; Drive 6 E2
M569 P7 S1 						; Drive 7 E3
M569 P8 S1 						; Drive 8 E4
;M569 P9 S1 						; Drive 9 E5

M584 X0 Y1 Z2:3:4 E5:6:7:8:9 									; Apply custom drive mapping 
M671 X567.8:567.8:-63 Y605.4:-40:250 S25                        ;3 point bed leveling
G31 Z20                                                    		; Probe depth
M208 X-59.4:553.6 Y-22.9:529.8 Z0:520            	 			; Set axis maxima & minima

M92 X80 Y80 Z4144:4144:4144 E404:404:404:920	    			; Set steps per mm assuming x16 microstepping 4144
M350 E16:16:16:16    I1 										; Configure microstepping with interpolation	
M350 X16 Y16 Z16:16:16 I1										; Configure microstepping with interpolation
M566 X300 Y300 Z12:12:12 E100:100:100:100  						; Set maximum instantaneous speed changes (mm/min)
M203 X50000 Y50000 Z500:500:500 E5000:5000:5000:5000	    	; Set maximum speeds (mm/min)
M201 X6000 Y6000 Z200:200:200 E6000:6000:6000:6000			    ; Set accelerations (mm/s^2)
M906 Z1300:1200:1200 I40   										; Idle motion motors to 40%   mA
M906 X2000 Y2000 E700:700:700:700 I20     			    		; Idle XY,extruder motors to 20%

; Endstops
M574 X2 S1 P"xstop"                                                                       ; configure active-high endstop for low end on X via pin xstop
M574 Y1 S1 P"ystop"
M591 																					  ; Configure filament-out sensors

;Filament runout sensors 
M591 P1 C"e0stop" S1       D0   ;P- typ S1- aktivní D0- extruder
M591 P1 C"e1stop" S1       D1   
M591 P1 C"duex.e2stop" S1   D2
M591 P1 C"duex.e3stop" S1   D3
;M591 P1 C"duex.e4stop" S1   D4

;Accelerometr
M955 P0 C"spi.cs3+spi.cs4" I05
M593 P"zvd" F31.5      ; imput shaping 
; Z probe

; setings for G29
M558 P8 C"zstop" H2.2 F300:300 I0 A5 S0.02 T20000 	; Set Z probe type to switch, the axes for which it is used and the dive height + speeds H- height, A-max repetetions, S- tolerance betwean multiple
G31 P200 X0 Y0 Z0	 								; Set Z probe trigger value, offset and trigger height
M557 X40:460 Y40:460 P6:6 							; Define mesh grid P - number of probs X:Y
;M376 H15											; bed compensation taper

; Heaters
M308 S0 P"bedtemp" Y"thermistor" A"Bed" T100000 B4725 C7.06e-8 	; Set thermistor 
M950 H0 C"bedheat" T0											; Bed heater
M143 H0 121													    ; Set temperature limit for heater 0 to 120C
M140 H0															; Bed heater is heater 0

M308 S1 P"e0temp" Y"thermistor" A"T0" T100000 B4725 C7.06e-8 	; Set thermistor
M950 H1 C"e0heat" T1											; Extruder 0 heater
M143 H1 S305 													; Set temperature limit for heater 1 to 300C

M308 S2 P"e1temp" Y"thermistor" A"T1" T4721000 B5462 C2.29788e-8 	; Set thermistor
M950 H2 C"e1heat" T2											; Extruder 0 heater
M143 H2 S450 													; Set temperature limit for heater 2 to 450C

M308 S3 P"e6temp" Y"thermistor" A"T2" T100000 B4725 C7.06e-8 	; Set thermistor
M950 H3 C"duex.e2heat" T3										; Extruder 0 heater
M143 H3 S305 													; Set temperature limit for heater 3 to 300C

M308 S4 P"e2temp" Y"thermistor" A"T3" T4721000 B5462 C2.29788e-8 	; Set thermistor
M950 H4 C"duex.e3heat" T4										; Extruder 0 heater
M143 H4 S455 													; Set temperature limit for heater 4 to 455C

;M308 S5 P"e4temp" Y"thermistor" A"T4" T100000 B4725 C7.06e-8 	; Set thermistor
;M950 H5 C"duex.e4heat" T5										; Extruder 0 heater
;M143 H5 S305 													; Set temperature limit for heater 4 to 300C


; Tools
M563 P0 S"T0" D0 H1 F4 					; Define tool 0
G10 P0 X0 Y0 Z0 						; Reset tool 0 axis offsets
G10 P0 R0 S0 							; Reset initial tool 0 active and standby temperatures to 0C

M563 P1 S"T1" D1 H2 F6 					; Define tool 1
G10 P1 X0 Y0 Z0 						; Reset tool 1 axis offsets
G10 P1 R0 S0 							; Reset initial tool 1 active and standby temperatures to 0C

M563 P2 S"T2" D2 H3 F8 					; Define tool 2
G10 P2 X0 Y0 Z0 						; Reset tool 2 axis offsets
G10 P2 R0 S0 							; Reset initial tool 2 active and standby temperatures to 0C

M563 P3 S"T3" D3 H4 F0 					; Define tool 3
G10 P3 X0 Y0 Z0 						; Reset tool 3 axis offsets
G10 P3 R0 S0 							; Reset initial tool 3 active and standby temperatures to 0C

M563 P4 S"Dial Indikator" 							; Define tool 4
G10 P4 X0 Y0 Z0 						; Reset tool 4 axis offsets
										; Reset initial tool 4 active and standby temperatures to 0C
										
M563 P5 S"Laser" 					    ; Define tool 5
G10 P5 X0 Y0 Z0 					 	; Reset tool 5 axis offsets


;Servo
M950 S0 C"exp.heater7"

;Laser

M452 C"fan2" F500 
M451

; Fans
M950 F1 C"fan0"                               ; T3/tool light
M950 F0 C"fan1"                               ;
;M950 F2 C"fan2"  							  ; Laser

M950 F3 C"duex.fan3"						  ;
M950 F4 C"duex.fan4"						  ;
M950 F5 C"duex.fan5"						  ;
M950 F6 C"duex.fan6"						  ;
M950 F7 C"duex.fan7"						  ;
M950 F8 C"duex.fan8"						  ;

M106 P1 S255 H4 T70 	  		; T3 PCF 
M106 P0 S0 						; T3 HE
M106 P3 S255 H1 T70				; T0 HE    P3=F3
M106 P4 S0						; T0 PCF
M106 P5 S255 H2 T70 			; T1 HE
M106 P6 S0						; T1 PCF 
M106 P7 S255 H3 T70 	    	; T2 HE 
M106 P8 S0 						; T2 PCF

;M593 F42.2						; cancel ringing at 42.2Hz (https://forum.e3d-online.com/threads/accelerometer-and-resonance-measurements-of-the-motion-system.3445/)

;tool offsets

;Z- Zmenšování čísla vede ke zvyšování trysky 
G10 P0 X-50.33 Y-2.33 Z-9.49			    ; T0
G10 P1 X-50.25 Y-0.96 Z-9.19		     	; T1
G10 P2 X-50.34 Y-0.99 Z-17.61			    ; T2
G10 P3 X-61.4 Y2.5 Z-6.8			 	 	; T3
G10 P4 X-55 Y-6 Z-8.2                       ; T4
G10 P5 X-85 Y-5.8 Z-18.81                   ; T5

;M572 D0 S0.2 						; pressure advance T0
;M572 D1 S0.2 						; pressure advance T1
;M572 D2 S0.2 						; pressure advance T2
;M572 D3 S0.2 						; pressure advance T3

M575 P1 S1 B57600				; Enable LCD
G29 S2							    ; disable mesh
T-1								      ; deselect tools
M911 S10 R11 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000"                                        ; set voltage thresholds and actions to run on power loss

;Defaultní retrakce S-vzdálenost retrakce, F-rychlost retrakce, T-rychlost deretrakce, R0- extra retrakce, Z0.4- Z hoop
M207 S1.5 F2400 T2400 R0 Z0.4
M207

M501                    ; load config-override.g

Here is how usual height map looks like:
https://imgtr.ee/image/Kog5W

Thanks for any tips and recommendations. I'm at dead end I can't figure it out.

[Phaedrux]

@MrHradaa22 said in Mesh bed leveling isn't working properly:

I thought it must be some kind of mechanical problem, but everything is solid.

I think it's a mechanical problem too. There may be a slight skew on the left Y member.

[MrHradaa22]

@Phaedrux
Thank you for your tip, I'm using cheap 1604 ballscrews and their runnout is terrible. So it might be a problem on it selve. So I might go to some T8 trapezoidal rods instead.

This is How it looks like