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Slicers & Macros

After installing, configuring, and calibrating klipper-toolchanger-easy, you need to set up your slicer to work with the toolchanger system.

klipper-toolchanger-easy provides a PRINT_START macro that must be used. It initializes the toolchanger, performs homing and QGL, and handles tool selection and heating. Your slicer should call it with the following parameters:

Required Parameters:

  • TOOL - The initial tool number to use (e.g., 0, 1, 2)
  • TOOL_TEMP - The temperature for the initial tool
  • BED_TEMP - The bed temperature

Optional Parameters (for multi-tool prints):

  • T0_TEMP, T1_TEMP, T2_TEMP, etc. - Pre-heat temperatures for tools that will be used in the print

Example:

PRINT_START TOOL=0 TOOL_TEMP=220 BED_TEMP=60 T0_TEMP=220 T1_TEMP=230

What the macro does:

  1. Initializes the toolchanger (INITIALIZE_TOOLCHANGER)
  2. Stops tool probe crash detection
  3. Heats the bed to BED_TEMP
  4. Homes all axes (G28)
  5. Selects T0
  6. Runs Quad Gantry Level (QUAD_GANTRY_LEVEL)
  7. Re-homes Z after QGL
  8. Selects the specified TOOL and heats it to TOOL_TEMP
  9. Pre-heats other tools if T0_TEMP, T1_TEMP, etc. are provided
  10. Restarts tool probe crash detection

Do not override the PRINT_START macro. If you need custom startup behavior, modify the macro in stealthchanger/macros.cfg or use the provided hooks.

The _PARK_ON_COOLING_PAD macro in PRINT_START is not needed for StealthChanger and can be commented out or removed if present.

Examples: - Minimal PRINT_START Example - Basic implementation - Advanced PRINT_START Example - Enhanced features with smart QGL selection and tool detection

Overview

  1. Slicer Software - Supported slicers for multi-tool printing
  2. Slicer GCODEs - Required start G-code and tool change G-code for each slicer

Slicer Software

Name Multitool Notes
Cura ✓ As of 5.8, select new printer, select DraftShift Design, select the size from the voron list, allows up to 8 extruders
OrcaSlicer ✓ As of 2.2
PrusaSlicer ✓
Simplify3D ?
Slic3r ?
SuperSlicer ✓ See 2197

Slicer GCODEs

Prusa

Printer -> Custom G-code -> Start G-code - all must be a single line

PRINT_START TOOL_TEMP={first_layer_temperature[initial_tool]} {if is_extruder_used[0]}T0_TEMP={first_layer_temperature[0]}{endif} {if is_extruder_used[1]}T1_TEMP={first_layer_temperature[1]}{endif} {if is_extruder_used[2]}T2_TEMP={first_layer_temperature[2]}{endif} {if is_extruder_used[3]}T3_TEMP={first_layer_temperature[3]}{endif} {if is_extruder_used[4]}T4_TEMP={first_layer_temperature[4]}{endif} {if is_extruder_used[5]}T5_TEMP={first_layer_temperature[5]}{endif}  BED_TEMP=[first_layer_bed_temperature] TOOL=[initial_tool]

Printer -> Custom G-code -> Tool change G-code

M104 S{temperature[next_extruder]} T[next_extruder] ; set new tool temperature so it can start heating while changing

NOTE: add this as a second line if you use prime tower

G1 X{wipe_tower_x} Y{wipe_tower_y} F{travel_speed*60} ; Move to wipe tower before tool change

Orca

Printer settings -> Machine G-code -> Machine start G-code - all must be a single line

PRINT_START TOOL_TEMP={first_layer_temperature[initial_tool]} {if is_extruder_used[0]}T0_TEMP={first_layer_temperature[0]}{endif} {if is_extruder_used[1]}T1_TEMP={first_layer_temperature[1]}{endif} {if is_extruder_used[2]}T2_TEMP={first_layer_temperature[2]}{endif} {if is_extruder_used[3]}T3_TEMP={first_layer_temperature[3]}{endif} {if is_extruder_used[4]}T4_TEMP={first_layer_temperature[4]}{endif} {if is_extruder_used[5]}T5_TEMP={first_layer_temperature[5]}{endif}  BED_TEMP=[first_layer_bed_temperature] TOOL=[initial_tool]

Printer settings -> Machine G-code -> Change Filament G-code

;Leave blank

Cura

Machine Settings -> Printer -> Start G-code - all must be a single line

For single tool prints:

PRINT_START TOOL_TEMP={material_print_temperature_layer_0} BED_TEMP={material_bed_temperature_layer_0} TOOL={initial_extruder_nr}

For multi-tool prints (Cura 5.8+):

PRINT_START TOOL_TEMP={material_print_temperature_layer_0} T{initial_extruder_nr}_TEMP={material_print_temperature_layer_0} {if material_print_temperature_layer_0[1]!=0}T1_TEMP={material_print_temperature_layer_0[1]}{endif} {if material_print_temperature_layer_0[2]!=0}T2_TEMP={material_print_temperature_layer_0[2]}{endif} {if material_print_temperature_layer_0[3]!=0}T3_TEMP={material_print_temperature_layer_0[3]}{endif} {if material_print_temperature_layer_0[4]!=0}T4_TEMP={material_print_temperature_layer_0[4]}{endif} {if material_print_temperature_layer_0[5]!=0}T5_TEMP={material_print_temperature_layer_0[5]}{endif} BED_TEMP={material_bed_temperature_layer_0} TOOL={initial_extruder_nr}

Machine Settings -> Printer -> Tool n -> Extruder Start G-code

;Leave blank

Machine Settings -> Printer -> Tool n -> Pre tool change G-code - 5.10+

M104 S{material_print_temperature} T{extruder_nr}

Optional Next Steps: - LEDs → Configure color LEDs and lighting effects

FAQ

Quick Links:

PrusaSlicer wipe tower position error after upgrading to 2.9.0

If you use G1 X{wipe_tower_x} Y{wipe_tower_y} F{travel_speed*60} in your Tool change G-code, it won't work in PrusaSlicer 2.9.0. They dropped the option to choose your wipe tower position, and the above command will give an error. Either don't use the wipe tower positions, or stick with PrusaSlicer 2.8.1 until it's fixed.

OrcaSlicer sets pressure advance to zero with prime tower

There is a bug in OrcaSlicer where it sets the pressure advance to zero when using a prime tower. See OrcaSlicer issue #7594. You can use a post-processing script to remove SET_PRESSURE_ADVANCE ADVANCE=0 from the g-code, or ensure your pressure advance values are set in your filament settings.

My tool waits a long time to heat up before continuing

This is likely Klipper waiting for the temperature of the hotend to settle to the target temperature. If your hotend is not well PID tuned, it can sometimes oscillate indefinitely around the target temperature. By default, this margin is quite small (only 0.5°C). This is usually not a problem for single toolhead printers, but with a toolchanger where it heats up the tool every tool call, this can introduce a lot of delay. Ensure your PID values are properly tuned for each tool.

How do I decrease the prime amount in OrcaSlicer?

Decreasing the Prime volume and width should work, but decreasing width just makes it longer. Adjust the Prime volume setting in your slicer's multi-material settings.

Can I use ooze prevention and pre-heating?

Yes! Ooze prevention is highly recommended for multi-tool printing. It reduces power draw by keeping inactive tools at a lower temperature, prevents filament from oozing, reduces heat creep, and prevents filament from cooking during long prints.

OrcaSlicer: - Location: Printer Settings → Multi-material → Ooze prevention - Temperature variation: Recommended 30-50°C below print temperature (e.g., if printing at 220°C, set idle temp to 170-190°C) - Pre-heat time: Recommended 15-30 seconds before tool change - This uses M104 to pre-heat and M109 to validate temperature before switching

PrusaSlicer: - Location: Printer Settings → Multi-material → Ooze prevention - Similar settings available as OrcaSlicer - Newer versions include an option to turn off tools completely when no longer needed

Benefits: - Reduced power draw: Only the active tool runs at full temperature, significantly reducing peak power requirements - Prevents oozing: Lower idle temperature prevents filament from oozing out of inactive nozzles - Prevents heat creep: Keeps filament from getting too hot in the heatbreak - Prevents filament degradation: Avoids cooking filament during long prints

Ensure your PID values are properly tuned for each tool, as the temperature will need to stabilize quickly when switching tools. If you experience long wait times during tool changes, you may need to adjust the temperature deadband in your M109 macro or increase the pre-heat time.