Mesh Bed Compensation NOT compensating enough

FelixH

how does your initial Gcode look like? Are you telling the printer to use the compensation? also, are you homing Z before you start the print?. The printer needs to know where your bed is and it does so with a G30 command. Depending of the printer's kinematics a G28 Z also suffices, I believe.

Phaedrux

@Tryptamine said in Mesh Bed Compensation NOT compensating enough:

G29 S1 "heightmap.csv"

Do not load the heightmap in config.g, you must only load it after Z0 has been established with the probe.

Please post your homing files and your slicer start gcode.

An image of your heightmap may also help.

Tryptamine

@FelixH said in Mesh Bed Compensation NOT compensating enough:

Are you telling the printer to use the compensation?

@Tryptamine said in Mesh Bed Compensation NOT compensating enough:

I see the compensation working.

The comp is working. The Z-Spindles are turning when I move in x-y- direction.

@Phaedrux said in Mesh Bed Compensation NOT compensating enough:

@Tryptamine said in Mesh Bed Compensation NOT compensating enough:

G29 S1 "heightmap.csv"

Do not load the heightmap in config.g, you must only load it after Z0 has been established with the probe.

Please post your homing files and your slicer start gcode.

An image of your heightmap may also help.

Really? I added that line later, the comp does also work just as bad when I uncomment this.

The reason I already load it in the config is to prevent the nozzle from moving into the bed.
I could otherwise move it into the bed, because My z axis minimum is -1 (which is necessary to allow height correction in negative z direction)

homeall.g:

; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v2.1.8 on Wed May 06 2020 00:49:52 GMT+0200 (Mitteleuropäische Sommerzeit)
G91                     ; relative positioning

G1 H2 Z3 F18000

G1 H1 X-350 F12000
G1 X5 F12000
G1 H1 X-350 F360            ; home X axis
G1 X5 F12000

G1 H1 Y-330 F12000
G1 Y5 F18000
G1 H1 Y-330 F360


G90 

G1 X145 Y139 F18000

G30
G1 X342 F18000

Slicer Start GCode:

M561
G28 ;Home
G29 S1 P"heightmap.csv"


G1 X350 Y20 F18000
G1 Z0

G1 X332 Y20 F18000
G1 Z0.2
G1 X330

G1 X315 Z0.25 F120 E50
;G91
;G1 E-5 F1000
;G90
G1 X330 Z0.2 F400
G4 P3000
G1 Z0.1 F9000
G1 X300 Z0.35 F18000

G1 X150 Y150 F18000
;G91
;G1 E5 F1000
;G90

Tryptamine

https://forum.duet3d.com/topic/16185/mesh-bed-leveling-not-moving-bed/2

Is from where I got the idea of changing the Z-Minimum to a negative value and adding the heightmap in the config to prevent bed crashes.

I thought this would solve the issue, which it did not.

FelixH

I can gladly share my config and initial gcodes, but I'm still running RRF2

Phaedrux

@Tryptamine said in Mesh Bed Compensation NOT compensating enough:

Z-Minimum to a negative value

This will help allow you to move down lower with baby stepping, but the mesh compensation should be able to adjust to follow the bed regardless because it's not going down below 0, it's adjusting to keep 0 at the surface of the bed. Provided of course that the probe has provided an accurate map of the surface of the bed.

Your homing files look alright. Loading the heightmap at startup without first establishing the bed surface can cause an offset in height. Loading it in the slier start gcode like you are doing is the correct way to do it.

Usually if the compensation isn't accurate to the bed surface it's because the probe offsets are incorrect, or the points measured aren't accurate either due to the probe itself not being consistent or due to effector tilt or other geometry problems twisting the probe/nozzle relation depending on XY position.

Peletor

Sorry to resurrect the dead, but did you ever figure out what was causing your issue?

I'm having the exact same problem (even running a hypercube) and I've been racking my brain on how to fix it. I've also recently moved over to a genuine BLTouch from a clone and it hasn't seemed to make a huge difference.

Any help would be appreciated!

Phaedrux

@Peletor slop in the Z axis eating up some of the compensation movement?

Peletor

@Phaedrux What do you mean slop? With the coupler between the stepper and the screw?

Phaedrux

@Peletor That's a possibility. Basically any stepper movement that doesn't directly translate into vertical movement. Mechanical mushiness.