G-code to manually change filament without AMS. See https://github.com/bambulab/BambuStudio/issues/278

change_filament_without_ams.gcode

;===== Change filament G-code without AMS ===
;===== version: 1.2 =========================
;===== original version date: 20230719 ======

;===== description ==========================
; Everything between M620 and M621 is executed only if AMS is connected.
; All M620, M620.x and M621 commands are removed to enable manual filament change.

; first filament change is skipped
{if toolchange_count > 1}
M204 S9000
{if z_hop_types[current_extruder] == 0 || z_hop_types[current_extruder] == 3}
G17
G2 Z{z_after_toolchange + 0.4} I0.86 J0.86 P1 F10000 ; spiral lift a little from second lift
{endif}
G1 Z{max_layer_z + 3.0} F1200

G1 X70 F21000
G1 Y245
G1 Y265 F3000
M400
M106 P1 S0
M106 P2 S0
{if old_filament_temp > 142 && next_extruder < 255}
M104 S[old_filament_temp]
{endif}
G1 X90 F3000
G1 Y255 F4000
G1 X100 F5000
G1 X120 F15000

G1 X20 Y50 F21000
G1 Y-3

;===== custom filament change ===============
; cut filament
G1 X5 F300
G1 X20 F12000

; move to poop chute
G1 X70 F12000
G1 Y245
G1 Y265 F3000

; push a little filament out and then retract out
G1 E10 F200
G1 E-10 F200
G1 E-20 F500

; pause for user to load and press resume
M400 U1

;===== continue =============================
{if next_extruder < 255}
M400

G92 E0
{if flush_length_1 > 1}
; FLUSH_START
; always use highest temperature to flush
M400
M109 S[nozzle_temperature_range_high]
{if flush_length_1 > 23.7}
G1 E23.7 F{old_filament_e_feedrate} ; do not need pulsatile flushing for start part
G1 E{(flush_length_1 - 23.7) * 0.02} F50
G1 E{(flush_length_1 - 23.7) * 0.23} F{old_filament_e_feedrate}
G1 E{(flush_length_1 - 23.7) * 0.02} F50
G1 E{(flush_length_1 - 23.7) * 0.23} F{new_filament_e_feedrate}
G1 E{(flush_length_1 - 23.7) * 0.02} F50
G1 E{(flush_length_1 - 23.7) * 0.23} F{new_filament_e_feedrate}
G1 E{(flush_length_1 - 23.7) * 0.02} F50
G1 E{(flush_length_1 - 23.7) * 0.23} F{new_filament_e_feedrate}
{else}
G1 E{flush_length_1} F{old_filament_e_feedrate}
{endif}
; FLUSH_END
G1 E-[old_retract_length_toolchange] F1800
G1 E[old_retract_length_toolchange] F300
{endif}

{if flush_length_2 > 1}
; FLUSH_START
G1 E{flush_length_2 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_2 * 0.02} F50
G1 E{flush_length_2 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_2 * 0.02} F50
G1 E{flush_length_2 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_2 * 0.02} F50
G1 E{flush_length_2 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_2 * 0.02} F50
G1 E{flush_length_2 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_2 * 0.02} F50
; FLUSH_END
G1 E-[new_retract_length_toolchange] F1800
G1 E[new_retract_length_toolchange] F300
{endif}

{if flush_length_3 > 1}
; FLUSH_START
G1 E{flush_length_3 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_3 * 0.02} F50
G1 E{flush_length_3 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_3 * 0.02} F50
G1 E{flush_length_3 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_3 * 0.02} F50
G1 E{flush_length_3 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_3 * 0.02} F50
G1 E{flush_length_3 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_3 * 0.02} F50
; FLUSH_END
G1 E-[new_retract_length_toolchange] F1800
G1 E[new_retract_length_toolchange] F300
{endif}

{if flush_length_4 > 1}
; FLUSH_START
G1 E{flush_length_4 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_4 * 0.02} F50
G1 E{flush_length_4 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_4 * 0.02} F50
G1 E{flush_length_4 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_4 * 0.02} F50
G1 E{flush_length_4 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_4 * 0.02} F50
G1 E{flush_length_4 * 0.18} F{new_filament_e_feedrate}
G1 E{flush_length_4 * 0.02} F50
; FLUSH_END
{endif}
; FLUSH_START
M400
M109 S[new_filament_temp]
G1 E2 F{new_filament_e_feedrate} ;Compensate for filament spillage during waiting temperature
; FLUSH_END
M400
G92 E0
G1 E-[new_retract_length_toolchange] F1800
M106 P1 S255
M400 S3
G1 X80 F15000
G1 X60 F15000
G1 X80 F15000
G1 X60 F15000; shake to put down garbage

G1 X70 F5000
G1 X90 F3000
G1 Y255 F4000
G1 X100 F5000
G1 Y265 F5000
G1 X70 F10000
G1 X100 F5000
G1 X70 F10000
G1 X100 F5000
G1 X165 F15000; wipe and shake
G1 Y256 ; move Y to aside, prevent collision
M400
G1 Z{max_layer_z + 3.0} F3000
{if layer_z <= (initial_layer_print_height + 0.001)}
M204 S[initial_layer_acceleration]
{else}
M204 S[default_acceleration]
{endif}
{else}
G1 X[x_after_toolchange] Y[y_after_toolchange] Z[z_after_toolchange] F12000
{endif}
{endif}

;===== AMS commands skip ====================
; Since there is no AMS, the following three lines are used solely to suppress
; the T[next_extruder] command.
; If these lines were omitted, the T[next_extruder] command would be executed
; after this code, leading to system hang as the toolchange command wait for the AMS.
M620 S[next_extruder]A
T[next_extruder]
M621 S[next_extruder]A

Thanks so much for sharing this! I was really surprised when I realized my P1P couldn't handle color changes on its own without an AMS, and this gcode saved my day. 🙌

I tried this on my P1S but it gets stuck forever purging on the first filament change.

Edit: Setting my purging volume multiplier to 0.1 fixed it, for some reason Bambu Studio set the purging volumes very high and you already purge a bunch when you do the manual filament change anyway.

Works like a charm, thanks!