Bed Levelling on RC8 working but not compensating

Hi, I am trying to set up bed levelling with RC8, I have a Z Probe on the Z Min stop.

Everything works fine, Homing to Z fine, G29 fine, G29 reporting looks fine, but when I actually try a print then it homes XY, homes Z, runs the bed levelling (G29), but when it actually gets to printing there is no Z compensation for the bed levels. I.e. I have a bed that is high in the Front Right, during printing the head is squashed to the bed at the front right and far enough above the bed at Back left that the extrusion wont stick.



Any help really appreciated.

Modify your G-code and introduce G29 after G92 E0 command. In my case this works.

Thanks but tried that and no joy. I did discover that the slicer was putting in an extra G92 E0 so I exported the GCode and edited it so G29 was after that but stil does the same thing.

Here's the start of the GCode and I've attached the configuration.h

; Generated with MatterSlice 1.0
; filamentDiameter = 1.75
; extrusionWidth = 0.4
; firstLayerExtrusionWidth = 0.4
; layerThickness = 0.2
; firstLayerThickness = 0.2
; automatic settings before start_gcode
M107 ; fan off
M190 S25
; wait for bed temperature to be reached

M104 T0 S205 ; start heating extruder 1

T0 ; set the active extruder to 0

; settings from start_gcode

G28 X Y; home XY axes

G28 Z

G90 ; use absolute coordinates

G21 ; set units to millimeters

G92 E0

M82 ; use absolute distances for extrusion

M109 S205 ; wait for temperature to be reached


; automatic settings after start_gcode

T0 ; set the active extruder to 0

G92 E0 ; reset the expected extruder position

G29
; Layer count: 8

; Layer Change GCode

; LAYER:0

..................

And for completeness the debug output following G29
<-Bed Level Correction Matrix:
<-+0.999954 +0.000000 -0.009590
<-+0.000018 +0.999998 +0.001875
<-+0.009590 -0.001875 +0.999952
<- current_position=(115.00, 15.00, 12.30) : G29 uncorrected XYZ
<-Z from Probe:12.60 Matrix:12.60 Discrepancy:0.00
<- current_position=(115.00, 15.00, 12.60) : G29 corrected XYZ
<-<<< gcode_G29
<-X:115.00 Y:15.00 Z:12.60 E:16.16 Count X: 11500 Y:1500 Z:4920
<- current_position=(115.00, 15.00, 12.60) : sync_plan_position
<-ok
<-ok T:107.5 /0.0 B:24.0 /0.0 @:0 B@:0
->N281 M105*44

<-ok T:107.5 /0.0 B:24.0 /0.0 @:0 B@:0
->N282 M114*47

<-X:115.00 Y:15.00 Z:12.60 E:16.16 Count X: 11512 Y:1498 Z:4921
<-ok
->N1 M110 N1*125

Pff.......i really don't know what to say.....I'm really sorry. In my case it compensate but it's not compensate enogh. I mean I see Z axes how rotates and try to compensate but they don t rotate enough and I don't know why. Here's my start G-code. Maybe it will help you

G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode
M107 ;start with the fan off
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0 ;move Z to min endstops
G1 Z10.0 F{travel_speed} ;move the platform up 15mm
G92 E0 ;zero the extruded length
G29 ;AutoBed Leveling
G1 X0 Y0
G1 Z-16.0 F{travel_speed}
G1 Y1.0 F1000.0 ;Go to this specific point from print area
G1 X60 E9.0 F1000.0
G1 X100 E15 F1000.0
G92 E0 ;zero the extruded length again
G1 F{travel_speed}
;Put printing message on LCD screen
M117 Printing...

Pain Over, loos like I discovered the issue, I moved G29 further down the start G code and its now working. the only remaining issue is that I have a weird setting for the z Probe offset, when measured its 2.2 mm but I have to use M851 Z-1.2 when I want it to print at the right height.

Not sure why the previous try didn't work, but thanks for your help.

I don't know... For me, setting my Z offset with G92 Z10 after G1 Z0 for example is not working and I'm using repetier. I mean on my LCD shows that Z is 10 but in my repetier on Z axis is still showing Z0. So I can't move Z down. And I'm using babystepping during the print to set my Z offset, witch is a pain in the ass. Tell me if your autobed leveling is working fine. I don t have a spring mounting for my bed and my autobed level is not compensating enough witch is really suck.

All of the parameters are loaded from the EEPROM. You need to do a M502 followed by a M500 to get the new values to stick. Or if you do a M851, follow it up with a M500 to save the value.

This is for me or for him?

Hi, thought it was all solved, It seems to all be working fine, and I see the Z motors turn as the head moves though the print so its adjusting the Z Height, but it doesn't seem to be adjusting enough. so if I print many things across the plate The back left has a thick first layer and the front right is squashed. As I say I can visibly see the Z motors adjusting height but it just seems that its not adjusting enough.

Hah......you tell me bro. I'm thinking about this for 2 weeks now on. I have the same problem...I still didn't found the solution. I think the autobed leveling procedure is good but for very small deviations of the bed like under 0.5mm or something like this. Otherwise I don't explain why. I'm waiting for somebody wise and kind enough in this forum to help us with a solution.

I might have to go back to using the software print levelling option until thi is properly sorted.

I am having the same issue all of a sudden...

I actually got it to work on my DIY The Beast (https://www.instagram.com/bywebberen/)
But lately it just ignores the values after the G29 command... I am at a loss as to what has changed. I have been in my conf.h file again and again. Also if i control the printer via repetier host open config it says auto bed leveling:1(in log) but has a 0 in the text box, if I change it to 1 it now says ERROR: Failed To

19:11:26.936 : Cap:AUTOLEVEL:1
19:11:26.936 : Cap:Z_PROBE:1
19:11:26.936 : Cap:LEVELING_DATA:1
19:11:26.936 : CapOFTWARE_POWER:0
19:11:26.936 : Cap:TOGGLE_LIGHTS:0
19:11:26.936 : Cap:CASE_LIGHT_BRIGHTNESS:0
19:11:26.936 : Cap:EMERGENCY_PARSER:0
19:11:26.936 : N11 M221 S100*80
19:11:26.938 : N12 M111 S6*84
19:11:26.938 : X:0.00 Y:0.00 Z:0.00 E:0.00 Count X:0 Y:0 Z:0
19:11:26.938 : echoEBUG:INFO,ERRORS
19:11:26.938 : echo:Active Extruder: 0
19:11:26.940 : N13 T0*8
19:11:26.940 : N14 M155 S1*85
19:11:26.961 : echoEBUG:INFO,ERRORS
19:11:26.961 : echo:Active Extruder: 0
19:11:56.178 : N15 M503*17
19:11:56.260 : echo: G21 ; Units in mm
19:11:56.260 : echo:Filament settings:
19:11:56.267 : echo: M200 D1.75
19:11:56.272 : echo: M200 T1 D1.75
19:11:56.272 : echoteps per unit:
19:11:56.294 : echo: M92 X80.00 Y80.00 Z400.00 E356.00
19:11:56.294 : echo:Maximum feedrates (units/s):
19:11:56.317 : echo: M203 X100.00 Y100.00 Z15.00 E100.00
19:11:56.317 : echo:Maximum Acceleration (units/s2):
19:11:56.335 : echo: M201 X2500 Y2500 Z50 E5000
19:11:56.335 : echo:Acceleration (units/s2): P R T
19:11:56.344 : echo: M204 P8000.00 R8000.00 T3000.00
19:11:56.345 : echo:Advanced: S T B X Z E
19:11:56.371 : echo: M205 S0.00 T0.00 B20000 X25.00 Y25.00 Z0.40 E5.00
19:11:56.372 : echo:Home offset:
19:11:56.386 : echo: M206 X0.00 Y0.00 Z0.00
19:11:56.386 : echo:Auto Bed Leveling:
19:11:56.395 : echo: M420 S0 Z0.01
19:11:56.396 : echoID settings:
19:11:56.413 : echo: M301 P21.60 I1.25 D93.33
19:11:56.413 : echo:Z-Probe Offset (mm):
19:11:56.418 : echo: M851 Z-0.40

Quote
pcsentinel2
Hi, thought it was all solved, It seems to all be working fine, and I see the Z motors turn as the head moves though the print so its adjusting the Z Height, but it doesn't seem to be adjusting enough. so if I print many things across the plate The back left has a thick first layer and the front right is squashed. As I say I can visibly see the Z motors adjusting height but it just seems that its not adjusting enough.

Which bed leveling system are you using? It sounds like it is the Grid Based or Linear bed leveling. That works well if your bed is flat. But even pieces of glass that look flat, are not flat. In that case, a mesh based bed leveling system is going to give you better results.