Modify Purge Line?

[etsellers]

I’m not too experienced in editing gcode, but I’m hoping that someone else here can help me.

I’d like to modify the purge line at the beginning of the print so that it doesn’t end back at the starting point.

When I use PETG, sometimes I get some oozing at the nozzle tip as it’s sitting there at the starting point while the hot end is getting to the target temperature.

When the purge line starts, this blob sticks to the bed right at the start of the purge. However, when the nozzle returns back to that point, it frequently picks the blob right back up and drags it to the beginning of the print.

If the purge line finished a couple of mm before the starting point, the blob would always remain stuck at the beginning where it should be.

[JonRaymond]

First of all welcome the forum.

Your rational behind changing the purge line makes sense. Luckily it’s an easy edit.

In “Printer settings/Machine G-code/Machine start G-Code” look for this section (it’s near the bottom)

;===== noozle load line ===============================
M975 S1
G90
M83
T1000
G1 X18.0 Y1.0 Z0.8 F18000;Move to start position
M109 S{nozzle_temperature_initial_layer[initial_extruder]}
G1 Z0.2
G0 E2 F300
G0 X240 E15 F{outer_wall_volumetric_speed/(0.3*0.5)     * 60}
G0 Y11 E0.700 F{outer_wall_volumetric_speed/(0.3*0.5)/ 4 * 60}
G0 X239.5
G0 E0.2
G0 Y1.5 E0.700
G0 X18 E15 F{outer_wall_volumetric_speed/(0.3*0.5)     * 60}
M400

To edit the position that the nozzle returns to you need to increas the X value on the second last line. So this line should be something like this to shorten the return by 3 mm.

G0 X21 E15 F{outer_wall_volumetric_speed/(0.3*0.5)     * 60}

You can check your edit in the G-code preview by scrolling the right vertical slider to the bottom (layer 1) and scrolling the horizontal slider to the far left. You can then step through the lines with the right arrow key.

[etsellers]

Thank you! This was exactly what I was looking for.

[droidxbrad]

perfect worked like a charm! Thank you

[Wsquared58]

Also, the stock nozzle wipe is junk. It it in the right front corner of the purge chute.
You might want to look at some of the creative solutions users have come up with to upgrade that stock wiper.
IMO I would not be surprised if Bambu Lab doesn’t upgrade that thing at some point themselves.