I understand that the z-offset can be tuned during a print. How to compose a temporary startup script that positions the nozzle front and center at the current z-offset. Then use the control box to increase/decrease until at .15mm. Possible?
I’m not sure if live Z adjust is available during a pause, since it prompts for a press of the wheel, and holding the wheel is how you get to the live Z adjust.
You could put all your homing and bed leveling portions of the startup into a separate .gcode file, which would do the homing and probing, and end with a G0 X80 Y10 Z0.15. From there, adjust up/down to get your height to Z0.15.
Then in your reduced startup .gcode in the actual file you’re printing, you would make sure there’s no G28 commands, and use G92 X80 Y10 Z0.15 to identify your manually adjusted position as the new position.
With it configured like that, you’d run your homing-leveling.gcode file, manually adjust up/down, then run the object.gcode file.
For all the trouble this has been though, you can get a BLTouch clone for $15, and I can give you the modified firmware I run on my Mini2.
This .gcode file accomplishes what I wanted. Just deleted temperature commands and added last two lines.
;Generated by Cura LulzBot Edition GCodeWriter Version: 3.6.40
;FLAVOR:Marlin
;TIME:6002
;Filament used: 0.395605m
;Layer height: 0.1
;Generated with Cura_SteamEngine 3.6.40-win10
M82 ;absolute extrusion mode
;This G-Code has been generated specifically for the LulzBot Mini 2 with SL 0.25mm Tool Head
;
M73 P0 ; clear GLCD progress bar
M75 ; Start GLCD Print Timer
G26 ; clear potential ‘probe fail’ condition
M107 ; disable fans
M420 S0 ; disable leveling matrix
G90 ; absolute positioning
M82 ; set extruder to absolute mode
G92 E0 ; set extruder position to 0
;M140 S65.0 ; start bed heating up
G28 ; home all axes
G0 X0 Y187 Z156 F400 ; move away from endstops
;M109 R150 ; wait for extruder to reach wiping temp
; ; ----------------------
; ; start x-level insert
G28 ; Home Axis
G0 X160 F9999 ; move toolhead to right
G0 Z5 F6000 ; Move to bottom of printer
G91 ; Set relative motion mode
M211 S0 ; Turn off soft endstops
M400 ; Finish moves
M906 Z600 ; Lower current to 600mA
G0 Z-15 F500 ; Skip steppers against lower Z mounts
G90 ; Return to absolute mode
M400 ; Finish moves
M906 Z960 ; Restore default current
M211 S1 ; Turn soft endstops back on
M400 ; Finish moves
G28 ; Rehome
M117 X-Axis Leveled ; progress indicator message on LCD
; ; end x-level insert
; ; ----------------------
G12 ; wiping sequence
; ; ----------------------
M206 X0 Y0 Z0 ; reseting stock nozzle position ### CAUTION: changing this line can affect print quality ###
G28 X0 Y0 ; home X and Y
M204 S300 ; set probing acceleration
G29 ; start auto-leveling sequence
M420 S1 ; enable leveling matrix
M204 S2000 ; restore standard acceleration
G1 X5 Y15 Z10 F5000 ; move up off last probe point
G4 S1 ; pause
M400 ; wait for moves to finish
M117 Mini2 Z-offset… ; progress indicator message on LCD
; ; ----------------------
G0 F1200 X80 Y10 Z0.15
G4 S180