AutoBed Leveling Offset


#1

First, many thanks to Marty Rice for the WIlson II plans. Just finished assembling and everything worked great.

Starting my first print. Sliced an object with CURA. I added a G29 to the start G code in Cura. The problem is that it starts the print about 5 mm above the buildplate, not matter what I have the Z Probe Offset set to in the COnfiguration.H file. Any suggestions?

Thanks.


#2

The way Marlin works, even if you change the offset value in configuration.h and re-program the board, it is going to keep using the current value stored in eeprom (this is a separate part of memory on the arduino, so it isn’t overwritten when you flash the firmware). So, you’ll need to go to the Control menu and choose “restore failsafes” to get it to load the value you put in the configuration header file.


#3

I tried that. Or, at least I changed the Z offset to -25, flashed it to the printer and then hit the Restore Failsafe. It went through the autobedleveling just fine, but then stopped with the extruder about 5 mm about the build plate, same as when the Z offset was set to -20. It’s like it just doesn’t want to go down any further.


#4

Got it! The Z offset was below the Z min (-10). I lowered the Z min to 15 and that fixed it.


#5

I have a follow up question on the AutoBed Leveling offset. How to see at which height the nozzle will be without having to print anything? I just want to see how low it goes (preferably only using the Smart controller).

Another question: does everyone autobedlevel before each print? Whenever I stop mid-print and start a print before ABL’ing again, the nozzle crashes into my bed.


#6

To see the height of your first layer without printing anything I believe you just move your Z axis to 0.

I set the start.gcode of Cura to run commands G28 and G29 to home and auto bedlevel so that it’s done with each print. I’m a newbie and don’t know much about gcode, I just copied the start.gcode and end.gcode from the gcode file that came on the SD card that shipped with my kit. Before I did this, with the default start.gcode in Cura, my nozzle also crashed into the bed at the beginning of each print.

start.gcode:

;Basic settings: Layer height: 0.24 Walls: 1.5 Fill: 70
;Print time: #P_TIME#
;Filament used: #F_AMNT#m #F_WGHT#g
;M190 S55 ;Uncomment to add your own bed temperature line
;M109 S205 ;Uncomment to add your own temperature line
G21        ;metric values
G90        ;absolute positioning
M82        ;set extruder to absolute mode
M107       ;start with the fan off
G28 ; home
G29 ; run auto bedlevel
G1 Z15.0 F6000 ;move the platform down 15mm
G92 E0                  ;zero the extruded length
G1 F200 E3              ;extrude 3mm of feed stock
G92 E0                  ;zero the extruded length again
G1 F6000
;Put printing message on LCD screen
M117 Printing...

end.gcode:

M104 S0                     ;extruder heater off
M140 S0                     ;heated bed heater off (if you have it)
G91                                    ;relative positioning
G1 E-1 F300                            ;retract the filament a bit before lifting the nozzle, to release some of the pressure
G1 Z+0.5 E-5 X-20 Y-20 F6000 ;move Z up a bit and retract filament even more
;G28 X0 Y50                              ;move X/Y to min endstops, so the head is out of the way
G1 X0 Y100
M84                         ;steppers off
G90                         ;absolute positioning
;{profile_string}

Hope that helps.


#7

I should have know… Thanks anyway.

Thanks too for your Cura code, I did not have the ABL included.