A350 startup gcode seems overengineered?

[chege54]

3dp-configs/PrusaSlicer/Snapmaker.ini

Line 3398 in 61e20e9

start_gcode = ; Model: Snapmaker A350\n; Update: 20240428\n; Maintained by https://github.com/macdylan/3dp-configs\n; Printer : [printer_preset]\n; Profile : [print_preset]\n; Plate : [physical_printer_preset]\n\nM201 X[machine_max_acceleration_x] Y[machine_max_acceleration_y] Z[machine_max_acceleration_z] E[machine_max_acceleration_e]\nM203 X[machine_max_feedrate_x] Y[machine_max_feedrate_y] Z[machine_max_feedrate_z] E[machine_max_feedrate_e]\nM204 P[machine_max_acceleration_extruding] R[machine_max_acceleration_retracting] T[machine_max_acceleration_travel]\nM205 X[machine_max_jerk_x] Y[machine_max_jerk_y] Z[machine_max_jerk_z] E[machine_max_jerk_e]\n\nT[initial_extruder]\n\nM140 S{first_layer_bed_temperature[initial_extruder]}\n\n; you can clean the nozzle\nM104 S165\nM204 S100\nG28\nG0 Z216 F960.0\nG0 Y175.0 F3420.0\nG0 X160.0\n\nM190 R{first_layer_bed_temperature[initial_extruder]}\n\nG28\n{if 1==1}\n G0 X0\n G0 Z0.2 F960.0\n G0 Y0 F3420.0\n G0 X320\n G0 Y350\n G0 X0\n G0 Y0\n{endif}\n\nM83\n{if 1==1 && max(first_layer_bed_temperature[initial_extruder], bed_temperature[initial_extruder]) >= 90}\nG0 Z0.06 ;raise z to counteract thermal expansion\nG92 Z0 ;reset z\n{endif}\n\nT[initial_extruder]\nM104 S{max(250, min(290, first_layer_temperature[initial_extruder] + 15))}; common flush temp\nG0 Z1.6 F960.0\nG0 X{if initial_extruder == 0}145.0{else}175.0{endif} F3420.0\nG0 Y0 F3420.0\n\nM109 S{max(250, min(290, first_layer_temperature[initial_extruder] + 15))} C2 W1; common flush temp\nG1 E15 F80.0\nG92 E0\n\nM106 S{min(255, (max_fan_speed[initial_extruder] + 10) * 2.55)}\n\nM104 S{first_layer_temperature[initial_extruder] + 5}\n\nG1 E9.0 F200\nG92 E0\nG1 E6.0 Z4.6 F200\nG92 E0\n\nG0 Z5.6 F200\nM107\n\nG0 X{if initial_extruder == 0}100.0{else}220.0{endif} F3420.0\nG0 Z0.3 F960.0\nM109 S{first_layer_temperature[initial_extruder]} C3 W1\nG1 E3 F200\nG92 E0\nG1 X{if initial_extruder == 0}0{else}320{endif} E6.23628 F3420.0\nG92 E0\n\nG1 E-{retract_length[initial_extruder]} F200\nG92 E0\nG0 Y20 F3420.0\n\n; ready [physical_printer_preset]

I would have a few question regarding to the A350 startup code:

• Why the head moved to the "center" of the bed?
  G0 X{if initial_extruder == 0}145.0{else}175.0{endif} F3420.0 in my opinion it would be better outside G0 X{if initial_extruder == 0}-5.0{else}...

• What is the meaning of C2 W1; and C3 W1?
  M109 S{max(250, min(290, first_layer_temperature[initial_extruder] + 15))} C2 W1; common flush temp
  ...
  M109 S{first_layer_temperature[initial_extruder]} C3 W1

• My experience is with this part:
  M104 S{first_layer_temperature[initial_extruder] + 5}
G1 E9.0 F200
G92 E0
G1 E6.0 Z4.6 F200
G92 E0
G0 Z5.6 F200
  extruder is standing in one place and extruding. The melted filament is backfiring on the nozzle and it gets clogged. Like so:
  
  What is the use case of it?

@macdylan: Please have a look on it if you have some time. Thank you so much!

[macdylan]

• Why the head moved to the "center" of the bed?

During nozzle warmup, it is easier to manually clean the nozzle and load the filament by moving to the central position. Especially when using enclosure.

• What is the meaning of C2 W1; and C3 W1?

https://github.com/Snapmaker/Snapmaker2-Controller/blob/7c88979c4f10d65c8950440fdf122ebb22bfd920/Marlin/src/gcode/temperature/M104_M109.cpp#L140

https://forum.snapmaker.com/t/discussion-of-snapmaker-2-0-firmware-updates/5441/688?u=macdylan

• ... The melted filament is backfiring on the nozzle and it gets clogged...

Your nozzle looks slightly blocked, please replace it with a new one. or the filament is wet :)

[chege54]

• Why the head moved to the "center" of the bed?

During nozzle warmup, it is easier to manually clean the nozzle and load the filament by moving to the central position. Especially when using enclosure.

• What is the meaning of C2 W1; and C3 W1?

https://github.com/Snapmaker/Snapmaker2-Controller/blob/7c88979c4f10d65c8950440fdf122ebb22bfd920/Marlin/src/gcode/temperature/M104_M109.cpp#L140

https://forum.snapmaker.com/t/discussion-of-snapmaker-2-0-firmware-updates/5441/688?u=macdylan

• ... The melted filament is backfiring on the nozzle and it gets clogged...

Your nozzle looks slightly blocked, please replace it with a new one. or the filament is wet :)

But the head is at Z1.6, which is too close to the print bed. How can you clean it? I can not access/reach it.

I dried the filament for 24 hours in a sunlu S2 drier, assume it is (totally) dry, I was able to print it without any issues from a luban generated code. Nozzle is blocked because print head it stayed in one position and extruded ~20mm filament under itself. (That is problem that I wanted to highlight)

Btw. Thank you for the C and W explanation. I did not found it in the docs. But it is documented via code 🙂

[macdylan]

But the head is at Z1.6, which is too close to the print bed. How can you clean it? I can not access/reach it.

Ohh, I read it wrong. I thought it was G0 Z216, but on Z1.6 it would look like this:

[chege54]

But the head is at Z1.6, which is too close to the print bed. How can you clean it? I can not access/reach it.

Ohh, I read it wrong. I thought it was G0 Z216, but on Z1.6 it would look like this:

Exactly

[jakubkinst]

I am experiencing the same problem. Since the purge is happening super-close to the build-plate, the nozzle actually gets clogged and dirty instead of the opposite. @macdylan can you please fix this part? Thanks

[chege54]

I am experiencing the same problem. Since the purge is happening super-close to the build-plate, the nozzle actually gets clogged and dirty instead of the opposite. @macdylan can you please fix this part? Thanks

thanks for confirming. I will try to (support to) solve it at the weekend, and lets see is it acceptable by @macdylan as well :)