Add Z clearance step before XY homing in homing override

[Copilot]

When a Z home is requested through the homing override, the printer should establish Z clearance before starting the X/Y homing sequence. This updates the macro so the bed/nozzle is lifted to a safe minimum height first, whether Z is already homed or not.

• Homing override behavior

  • Detect when the current G28 request includes Z homing (G28, G28 Z, etc.)
  • Before any X/Y homing:
    • If Z is already homed and below 8mm, move to Z=8
    • If Z is not homed, force-move Z upward by 8mm to create clearance

• Macro cleanup

  • Keep the clearance height and normal move feedrate as named variables
  • Inline the single-use Z-home condition instead of storing it in a separate variable
  • Derive the unhomed FORCE_MOVE velocity from safe_z_feedrate / 60
  • Document the printer-specific assumptions around the unhomed Z FORCE_MOVE
  • Wait for the Z clearance move to complete before continuing into the existing XY homing flow

• Resulting macro path

  {% if home_all or 'Z' in params %}
    {% if 'z' in printer.toolhead.homed_axes %}
      {% if printer.gcode_move.gcode_position.z|float < safe_z %}
        G90
        G0 Z{safe_z} F{safe_z_feedrate}
      {% endif %}
    {% else %}
      FORCE_MOVE STEPPER=stepper_z DISTANCE={safe_z} VELOCITY={safe_z_feedrate / 60}
    {% endif %}
    M400
  {% endif %}

[github-actions]

✅ Build Artifacts

Branch: copilot/force-move-bed-down-5mm
Build: 046132b (merge into main)

Artifact	Size
CC1 Firmware	89.86 MB

View workflow run

[suchmememanyskill]

Can't properly test this til tomorrow evening

[jaimbo]

Just tested these changes and it seems to work well.

• If z is not homed, G28 will force drop the Z axis before homing
• If Z is homed but within 5mm of the nozzle, Z is dropped an amount before homing
• If Z is homed but more than 5mm away from the nozzle, homing proceeds as normal.
• I don't expect there is a way to avoid this, but if the bed is at max Z, not homed - it will force move the Z by 5mm and give some pretty miserable grinding sounds...

I think I prefer that to the bed being destroyed though :)

This all seems to work whether using G28 to home all or G28 Z for just Z