Area of g-code before "Custom Code"

[Galaxyhunter 0]

Hello All, I'm fairly new to 3d printing and new to Cura.  I have spent 25 years programing & running CNC machines including customizing their post processors, so I'm familiar with working with g-codes.   So I just loaded a profile for an Ender3 pro.  When I create a gcode file, I noticed that it heats the bed & tip before the homing function. this is leading to filament

oozing during the homing.  This code is place before the area where the custom codes are entered. 

 

;Generated with Cura_SteamEngine 4.13.1
M140 S60
M105
M190 S60
M104 S205
M105
M109 S205
M82 ;absolute extrusion mode
; Ender 3 Custom Start G-code

G92 E0 ; Reset Extruder
G28 ; Home all axes
G29 ; Bed Leveling

 

Is there a cfg file that can be edited that I can change this?  I would like to end up with doing the Home (G28) and the Auto Bed Leveling (G29) before the command to turn the heaters on.

[GregValiant 980]

Here ya go.  You can copy and paste this into the StartUp Gcode box in your machine settings.  By heating the hot end part-way (I used 160°) before leveling it avoids oozing, but takes up some of the possible expansion of the hot end parts.  The purge lines speeds (F3000) are suitable for PLA but not so much for PETG or TPU.  You would need to make adjustments if you print those materials.  The words in curly brackets {} are replacement patterns.  Cura will insert the numbers when the gcode is created.  When Cura sees the replacement patterns in the Startup Gcode then it won't insert those early temperature lines.

;

; E3Pro StartUp

;

M82 ;Absolute extrusion

G90 ;Absolute movement

G21 ;Metric units

M140 S{material_bed_temperature_layer_0} ;start to heat the bed

M109 S160 ;start to heat the hot end and wait for it

M190 S{material_bed_temperature_layer_0} ;wait for the bed

G92 E0 ; Reset E

G28; Home all axes

G29 ;Auto-level

M109 S{material_print_temperature_layer_0} ;final heating of the hot end and wait

M220 S100 ;reset the feed rate in case of tuning during a previous print

M221 S100 ;reset the flow rate in case of tuning during a previous print

G1 Z10.0 F3000 ; Move Z

G1 X1.0 Y20 ;Move to start of purge

G1 X1.0 Y20 Z0.3 F5000.0 ; Move down

G1 X1.0 Y200.0 Z0.3 F3000.0 E12 ; First purge line

G1 X3.0 Y200.0 Z0.3 F5000.0 ; Move

G1 X3.0 Y20 Z0.3 F3000.0 E24 ; Second purge line

G1 E22 F1800 ;short retraction

G92 E0 ; Reset Extruder

G1 Z12.0 F3000 ; Move Z Axis up

G1 X20 Y35 F5000.0 ; Move over

;

;End of StartUp

;

 

[Galaxyhunter 0]

Thank You Greg, I'll load it up & give it a try.  🙂

 

                           Carl.

[GregValiant 980]

I just answered another post regarding this same thing and I realized I missed a couple of lines in there.

Change this:

G29 ;Auto-level

M109 S{material_print_temperature_layer_0} ;final heating of the hot end and wait

 

to this:

G29 ;Auto-level

G1 Z15 F1000

G1 X1 Y1 F6000

M109 S{material_print_temperature_layer_0} ;final heating of the hot end and wait

That will raise the Z and then park the head in the LF corner so it oozes over there instead of over the build plate.

[Galaxyhunter 0]

Got It.