2nd print too high and z-offset is inconsistent,config problem?

o_lampe

@lui2004 In your homeall.g you change M558 (z-probe setting) twice.
Just to be sure, I also repeat the G31 line everytime I change M558. I'm afraid it'll use default values instead, if I don't. (paranoid?)

Another sidenote: you drop the motorcurrent a lot while probing, but still use the full probing speed. How can you be sure, not to skip steps while probing?

lui2004

@o_lampe

Hi

thanks for reply !

what do you thing i must change on my config?
i am not an expert

o_lampe

Your homeall.g:

M558 F600 A1 		; Dive fast once
G30			; probe Z
M558 F100 A10 		; Slow second dive with more accuracy
G30			; probe z again

Adding G31 from config.g:

M558 F600 A1 		; Dive fast once
G31 P500 X-52 Y0 Z0.689 C0.0010 S20 H5                 ; set Z probe trigger value, offset and trigger height
G30			; probe Z
M558 F100 A10 		; Slow second dive with more accuracy
G31 P500 X-52 Y0 Z0.689 C0.0010 S20 H5                 ; set Z probe trigger value, offset and trigger height
G30			; probe z again

I'd also outcomment the M913 current reduction

lui2004

@o_lampe

rest of config looks good ?

ok,now it looks like this:

homeall.g

; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v3.3.4 on Thu Oct 14 2021 05:57:31 GMT+0200 (Mitteleuropäische Sommerzeit)
;M913 X35 Y35 Z35	    ; Reduce motor currents for homing
G91                     ; relative positioning
G1 H2 Z5 F6000          ; lift Z relative to current position
G1 H1 X 240 F3000 ; move quickly to X axis endstop and stop there (first pass)
G1 H1 Y 240 F3000 ; move quickly to Y axis endstop and stop there (first pass)
G1 H2 X-5 Y-5 F6000       ; go back a few mm
G90                     ; absolute positioning

G1 X162 Y110 F2000 ; put head over the centre of the bed, or wherever you want to probeG30                     ; home Z by probing the bed
M558 F600 A1 		; Dive fast once
G31 P500 X-52 Y0 Z0.689 C0.0010 S20 H5                 ; set Z probe trigger value, offset and trigger height
G30			; probe Z
M558 F100 A10 		; Slow second dive with more accuracy
G31 P500 X-52 Y0 Z0.689 C0.0010 S20 H5                 ; set Z probe trigger value, offset and trigger height
G30			; probe z again
G29 S1			; Load heightmap and enable mesh grid compensation
G1 X235 Y235 Z10 F6000	; return head to park position
M913 X100 Y100 Z100	; Return motor currents to normal

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

lui2004

I use Prusaslicer
can you check my Start G-Code and End Gcode,please ?

Start G-Code:

T0
G28 XY ;Home XY
M561 ; Clear any bed transform that might be in place
G1 X162 Y110  ; Move Probe to middle of bed
G30 ; Do a single probe
G29 S1 ; Load my custom heightmap. Otherwise use G29 S1
G92 E0 ;Reset Extruder
G1 Z2.0 F3000 ;Move Z Axis up
M104 S[first_layer_temperature] ; set final nozzle print temp
M109 S[first_layer_temperature] ; wait for the nozzle to heat up
G1 X10.1 Y20 Z0.28 F5000.0 ;Move to start position
G1 X10.1 Y200.0 Z0.28 F1500.0 E15 ;Draw the first line
G1 X10.4 Y200.0 Z0.28 F5000.0 ;Move to side a little
G1 X10.4 Y20 Z0.28 F1500.0 E30 ;Draw the second line
G92 E0 ;Reset Extruder

End G-Code:

M106 S0 ; turn off cooling fan
M104 S0 ; turn off extruder
M140 S0 ; turn off bed
G91 ; set to relative positioning
G1 Z5 ; raise Z 5 mm
G90 ; set to absolute positioning
G1 X235 Y235 ; park at X0 Y0
M84 ; disable motors

cosmowave

@lui2004 your end code is not really nice if you print an object near zmax! So the z axle can't raise 5mm.

I have the following code in stop.g

G91								; relative positioning
if {move.axes[2].userPosition +5} < move.axes[2].max		; possible to move z+5 ?
	G0 Z+5							; move z 5mm away from nozzle
else 
	G0 Z+{move.axes[2].max - move.axes[2].userPosition}	; move z to the max possible position

It moves the z axle 5mm if it is possible.
If not, it moves to zmax.

lui2004

@cosmowave said in 1st print perfect,2nd print too high,config problem ?:

G91 ; relative positioning if {move.axes[2].userPosition +5} < move.axes[2].max ; possible to move z+5 ? G0 Z+5 ; move z 5mm away from nozzle else G0 Z+{move.axes[2].max - move.axes[2].userPosition} ; move z to the max possible position

ok iadd this code in my Duet Stop.g
do i need to change something in my End G-Code ?

o_lampe

@lui2004 In your start code, you only home XY (G28 XY) Now that we have changed homeall.g, you can replace it with a simple G28.
New start code:

T0
M561 ; Clear any bed transform that might be in place
G28  ;Home all
G29 S1 ; Load my custom heightmap. Otherwise use G29 S1
... ; rest is OK

cosmowave

@lui2004 you should insert my code in your end code (at the position where you raise the z axle), not in stop.g. Because you disable the motors in your end code.
Stop.g will be called afterwards, and with disabled motors it will be not possible to move z!

e.g. your modified end code:

M106 S0 ; turn off cooling fan
M104 S0 ; turn off extruder
M140 S0 ; turn off bed
G91	; relative positioning
if {move.axes[2].userPosition +5} < move.axes[2].max; possible to move z+5 ?
	G0 Z+5; move z 5mm away from nozzle
else 
	G0 Z+{move.axes[2].max - move.axes[2].userPosition}; move z to the max possible position
G90 ; set to absolute positioning
G1 X235 Y235 ; park at X0 Y0
M84 ; disable motors

lui2004

@cosmowave said in 1st print perfect,2nd print too high,config problem ?:

M106 S0 ; turn off cooling fan M104 S0 ; turn off extruder M140 S0 ; turn off bed G91 ; relative positioning if {move.axes[2].userPosition +5} < move.axes[2].max; possible to move z+5 ? G0 Z+5; move z 5mm away from nozzle else G0 Z+{move.axes[2].max - move.axes[2].userPosition}; move z to the max possible position G90 ; set to absolute positioning G1 X235 Y235 ; park at X0 Y0 M84 ; disable motors

i got this error from prusaslicer:

G-code export to C:\Users\Lfna\AppData\Local\Temp\.2324.gcode failed due to invalid custom G-code sections:
end_gcode
Parsing error at line 5: Not a variable name
if {move.axes[2].userPosition +5} < move.axes[2].max; possible to move z+5 ?
    ^
Please inspect the file C:\Users\Lfna\AppData\Local\Temp\.2324.gcode.tmp for error messages enclosed between
        !!!!! Failed to process the custom G-code template ...
and
        !!!!! End of an error report for the custom G-code template ...
for all macro processing errors.

cosmowave

@lui2004 ok, then it could be, that this code is not allowed in prusa slicer.
I use it in stop.g, so it's slicer independent....
Sorry for that!

lui2004

@cosmowave

no problem !

now i have follow problem, my z-offset shows me different z-offsets:
whats going wrong here ?

Stopped at height 0.709 mm
Stopped at height 0.729 mm
Stopped at height 0.739 mm
Stopped at height 0.756 mm
Stopped at height 0.697 mm
Stopped at height 0.696 mm
Stopped at height 0.697 mm

lui2004

Morning

the problem with the second preresist,the second print is always too high

i must shutdown the printer and then is all fine and the second print is again high

i dont know why

cosmowave

@lui2004 About this i can't say much. I don't use a z-probe...
Do you use babystepping during the first print?

Can you please post your startcodes once again?

lui2004

@cosmowave

no, i dont use babystep for the first print ,its all fine

prusa slicer start g-code:

T0
G28 XY ;Home XY
M561 ; Clear any bed transform that might be in place
G1 X162 Y110  ; Move Probe to middle of bed
G30 ; Do a single probe
G29 S1 ; Load my custom heightmap. Otherwise use G29 S1
G92 E0 ;Reset Extruder
G1 Z2.0 F3000 ;Move Z Axis up
M104 S[first_layer_temperature] ; set final nozzle print temp
M109 S[first_layer_temperature] ; wait for the nozzle to heat up
G1 X10.1 Y20 Z0.28 F5000.0 ;Move to start position
G1 X10.1 Y200.0 Z0.28 F1500.0 E15 ;Draw the first line
G1 X10.4 Y200.0 Z0.28 F5000.0 ;Move to side a little
G1 X10.4 Y20 Z0.28 F1500.0 E30 ;Draw the second line
G92 E0 ;Reset Extruder

end g-code:

M106 S0 ; turn off cooling fan
M104 S0 ; turn off extruder
M140 S0 ; turn off bed
G91 ; set to relative positioning
G1 Z5 ; raise Z 5 mm
G90 ; set to absolute positioning
G1 X235 Y235 ; park at X0 Y0
M84 ; disable motors

cosmowave

@lui2004 And when you use a startcode like @o_lampe said in his post (without G30)?

T0
M561 ; Clear any bed transform that might be in place
G28  ;Home all
G29 S1 ; Load my custom heightmap. Otherwise use G29 S1
...

lui2004

@cosmowave

i dont have tested!

i will test it after work

o_lampe

@cosmowave @lui2004
The start code in my slicer is always empty. Also my homeall.g only calls homeX, homeY, homeZ.
I want only one file, I have to edit.

My guess is, you G30-probe the bed after the heightmap is loaded, which changes the Z-height

lui2004

@o_lampe
Thanks ,i will test it after work

Phaedrux

@o_lampe said in 2nd print too high and z-offset is inconsistent,config problem?:

I also repeat the G31 line everytime I change M558. I'm afraid it'll use default values instead, if I don't. (paranoid?)

Definitely paranoid. The G31 restatement is unneeded.

@cosmowave said in 2nd print too high and z-offset is inconsistent,config problem?:

your end code is not really nice if you print an object near zmax! So the z axle can't raise 5mm.
It moves the z axle 5mm if it is possible.
If not, it moves to zmax.

Also unnecessary. If the axis limits are set correctly, the firmware won't allow it to go beyond z max anyway, so a relative move close to the z limit would stop at zmax regardless. No need for conditional gcode there.

@lui2004 Did you end up figuring out your problem with the second print start?