The height map is not created correctly

[kotuo]

@phaedrux Thank you for your reply.

@phaedrux said in The height map is not created correctly:

Do you actually use bed.g? Or call it with G32 at any point?

I ran G32 and found that P1 and P4 were not probed as the probes were sticking out of the bed.

@phaedrux said in The height map is not created correctly:

homeall.gファイルとhomez.gファイルを投稿できますか？

This is Homeall

; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v3.3.5 on Sun Nov 14 2021 09:23:55 GMT+0900 (日本標準時)
G91                     ; relative positioning
G1 H2 Z5 F6000          ; lift Z relative to current position
G1 H1 X-305 Y-305 F1800 ; move quickly to X and Y axis endstops and stop there (first pass)
G1 H2 X5 Y5 F6000       ; go back a few mm
G1 H1 X-305 Y-305 F360  ; move slowly to X and Y axis endstops once more (second pass)
G1 H1 Z-305 F360        ; move Z down stopping at the endstop
G90                     ; absolute positioning
G92 Z0                  ; set Z position to axis minimum (you may want to adjust this)

; Uncomment the following lines to lift Z after probing
;G91                    ; relative positioning
;G1 Z5 F100             ; lift Z relative to current position
;G90                    ; absolute positioning

This is Homez

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.3.5 on Sun Nov 14 2021 09:23:56 GMT+0900 (日本標準時)
G91 ; relative mode
G1 S2 Z5 F200 ; raise head 4mm to ensure it is above the Z probe trigger height
G90 ; back to absolute mode
G1 X150 Y150 F2000 ; put head over the centre of the bed, or wherever you want to probe
G30 ; lower head, stop when probe triggered and set Z to trigger height

;G91               ; relative positioning
;G1 H2 Z5 F6000    ; lift Z relative to current position
;G1 H1 Z-305 F1800 ; move Z down until the endstop is triggered
;G92 Z0            ; set Z position to axis minimum (you may want to adjust this)

; Uncomment the following lines to lift Z after probing
;G91              ; relative positioning
;G1 Z5 F100       ; lift Z relative to current position
;G90              ; absolute positioning

@phaedrux said in The height map is not created correctly:

When the heightmap has such a large offset it's usually because the mesh has been created without the z axis being homed with the probe first.

Now I understand why the height map was made so low.

@phaedrux said in The height map is not created correctly:

Your homing files should home the Z axis with the probe using G30 at the center of the bed to set the Z0 location. Then create a fresh height map.

Does this mean that I need to do a paper filler test in the centre of the bet and then run 「G92 Z0」 and then 「G29」?

[droftarts]

@kotuo said in The height map is not created correctly:

Does this mean that I need to do a paper filler test in the centre of the bet and then run 「G92 Z0」 and then 「G29」?

You shouldn't need to set the Z axis 0 manually, as you have a probe to do that, and it looks like when you home Z properly, it works okay. I think the problem is that your homeall.g file is incorrect.

At the moment, your homez.g homes the Z axis in the middle of the bed, with:

G1 X150 Y150 F2000 ; put head over the centre of the bed, or wherever you want to probe
G30 ; lower head, stop when probe triggered and set Z to trigger height

but your homeall.g just sets Z=0 at whatever height the Z is at after homing X and Y:

G92 Z0                  ; set Z position to axis minimum (you may want to adjust this)

Replace the G92 line in homeall.g with the two lines from homez.g, then a home all should home Z in the middle of the bed. If the nozzle doesn't touch the bed when you move Z to 0, check your probe offset: https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe#Section_Calibrate_the_Z_probe_trigger_height

Your bed mesh looks better, but now shows that the bed is twisted, or that the bed rails are not level (one side rises compared to the other) or that the nozzle carriage twists around the Y axis as it moves from one side to the other (if your bed still moves in X). If your bed has corner adjusters, you can use the manual bed levelling assistant to tell you how far to adjust the bed: https://duet3d.dozuki.com/Wiki/Using_the_manual_bed_levelling_assistant

That should get you closer to a flat bed. It's always best to get the bed as mechanically level as possible, so the bed mesh compensation isn't having to work too hard.

Ian

[kotuo]

@droftarts Sorry for the delay in replying.
Thank you for your reply.
I have reworked the parts you pointed out.

I rewrote homeall.g and it looks like this.

; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v3.3.5 on Sun Nov 14 2021 09:23:55 GMT+0900 (日本標準時)
G91                     ; relative positioning
G1 H2 Z5 F6000          ; lift Z relative to current position
G1 H1 X-305 Y-305 F1800 ; move quickly to X and Y axis endstops and stop there (first pass)
G1 H2 X5 Y5 F6000       ; go back a few mm
G1 H1 X-305 Y-305 F360  ; move slowly to X and Y axis endstops once more (second pass)
G1 H1 Z-305 F360        ; move Z down stopping at the endstop
G90                     ; absolute positioning
G1 X150 Y150 Z5 F2000 ; put head over the centre of the bed, or wherever you want to probe
G30 ; lower head, stop when probe triggered and set Z to trigger height


;G92 Z0                  ; set Z position to axis minimum (you may want to adjust this)

; Uncomment the following lines to lift Z after probing
;G91                    ; relative positioning
;G1 Z5 F100             ; lift Z relative to current position
;G90                    ; absolute positioning

As a result, when HomeAll is done, after the X and Y axis hit the limit switch, the carriage moves to the centre and is now Z-probed.

The next question is about the probe offset.
This is a CAD simulation of my probe.


You will probably need to enter X+20 or X-20 as the offset for G31.
I have checked the offset and if I move the probe to where the hot end nozzle is marked, then at +20mm the probe will be in the same position as the nozzle.
I set it to X20 on the G31.
However, I don't think that the Y axis offset is moving from the nozzle to either side. In this case, is it correct to set the Y offset to 0?

The next question is about Using the Manual Bed Levelling Assistant.
The prerequisite for Using the Manual Bed Levelling Assistant is
｛You need to use the {M671 command to define the X and Y coordinates of the adjusting screw. The M671 command must be specified after the M667 or M669 command in config.g}.
but the adjustment screw on my printer bed is on the inside of the bed.
Is this something I should be concerned about?
Also, there is no M669 in my Config.g. What should I do in this case?

[Phaedrux]

Is the probe in front or behind the nozzle? To the left or the right?

+X should be to the right, -X to the left, -Y to the front, +Y behind.

@kotuo said in The height map is not created correctly:

but the adjustment screw on my printer bed is on the inside of the bed.

That's fine. Just provide the absolute positions of the screws.

@kotuo said in The height map is not created correctly:

Also, there is no M669 in my Config.g. What should I do in this case?

That's fine. Do nothing.

[droftarts]

@phaedrux said in The height map is not created correctly:

Is the probe in front or behind the nozzle? To the left or the right?

+X should be to the right, -X to the left, -Y to the front, +Y behind.

Except @kotuo has the bed moving in X, and the extruder carriage moving in Y, so the sensor behind the nozzle is at, I think, X-20 Y0 when the nozzle is at the origin.

@kotuo said in The height map is not created correctly:

Also, there is no M669 in my Config.g. What should I do in this case?

That's fine. Do nothing.

To elaborate on this, M669 sets the printer kinematics. The default is cartesian, which your machine is, so you don’t need M669 explicitly.

Ian

[droftarts]

@kotuo does this picture show the nozzle at X0 Y0?

If the bed is moving in X, and the extruder carriage in Y, this should be the maximum X point, not minimum.

Ian

[kotuo]

@droftarts　Thank you for your reply.
This picture is taken from the back of the printer.
Y is about -20 places from the maximum
X is about two thirds of the way from the minimum.
In the printer settings, this is the maximum position.
In order to improve the serviceability of the printer, the bed can be moved up to 500mm

[kotuo]

@droftarts 　Thank you for your reply.

@droftarts said in The height map is not created correctly:

Is the probe in front or behind the nozzle? To the left or the right?

The nozzle is in front of the printer. And the probe is set at 20mm in front from the nozzle.

[kotuo]

@phaedrux 　Thank you for your reply.
I now understand the relationship between X and Y. Thank you.

[kotuo]

@droftarts @phaedrux Thank you for your kind remarks to my ignorance.
I finished setting up the M671 today. The result on Bed.g looks like this.
Bed image:
G32Results：G32
Manual corrections required: 0.00 turn up (0.00mm) 0.19 turn down (0.09mm) 0.13 turn down (0.07mm) 0.19 turn down (0.10mm)
Thank you for telling us.
I don't think I could have done so much with my knowledge.