Klipper mesh on print area only install guide

What this macro do

• This macro will dymanic change the bed_mesh area based on the size of the printed part. The fw will only probe on the area that the part will be printed (plus mesh_area_offset value)

Setup guide

• (1) Add the following macrro to your printer config, this will replace the default BED_MESH_CALIBRATE command.

[gcode_macro BED_MESH_CALIBRATE]
rename_existing: BED_MESH_CALIBRATE_BASE
; gcode parameters
variable_parameter_AREA_START : 0,0
variable_parameter_AREA_END : 0,0
; the clearance between print area and probe area 
variable_mesh_area_offset : 5.0
; number of sample per probe point
variable_probe_samples : 2
; minimum probe count
variable_min_probe_count : 3
; scale up the probe count, should be 1.0 ~ < variable_max_probe_count/variable_min_probe_count
variable_probe_count_scale_factor : 1.0
gcode:
    {% if params.AREA_START and params.AREA_END %}
        {% set bedMeshConfig = printer["configfile"].config["bed_mesh"] %}
        {% set safe_min_x = bedMeshConfig.mesh_min.split(",")[0]|float %}
        {% set safe_min_y = bedMeshConfig.mesh_min.split(",")[1]|float %}
        {% set safe_max_x = bedMeshConfig.mesh_max.split(",")[0]|float %}
        {% set safe_max_y = bedMeshConfig.mesh_max.split(",")[1]|float %}

        {% set area_min_x = params.AREA_START.split(",")[0]|float %}
	{% set area_min_y = params.AREA_START.split(",")[1]|float %}
	{% set area_max_x = params.AREA_END.split(",")[0]|float %}
	{% set area_max_y = params.AREA_END.split(",")[1]|float %}

	{% if bedMeshConfig.probe_count.split(",")|length == 2 %}
            {% set meshPointX = bedMeshConfig.probe_count.split(",")[0]|int %}
            {% set meshPointY = bedMeshConfig.probe_count.split(",")[1]|int %}
        {% else %}
            {% set meshPointX = bedMeshConfig.probe_count.split(",")[0]|int %}
            {% set meshPointY = bedMeshConfig.probe_count.split(",")[0]|int %}
        {% endif %}

	{% set meshMaxPointX = meshPointX %}
	{% set meshMaxPointY = meshPointY %}


        {% if (area_min_x < area_max_x) and (area_min_y < area_max_y) %}
            {% if area_min_x - mesh_area_offset >=  safe_min_x %}
                {% set area_min_x = area_min_x - mesh_area_offset %}
            {% else %}
                {% set area_min_x = safe_min_x %}
            {% endif %}

            {% if area_min_y - mesh_area_offset >=  safe_min_y %}
                {% set area_min_y = area_min_y - mesh_area_offset %}
            {% else %}
                {% set area_min_y = safe_min_y %}
            {% endif %}

            {% if area_max_x + mesh_area_offset <=  safe_max_x %}
                {% set area_max_x = area_max_x + mesh_area_offset %}
            {% else %}
                {% set area_max_x = safe_max_x %}
            {% endif %}

            {% if area_max_y + mesh_area_offset <=  safe_max_y %}
                {% set area_max_y = area_max_y + mesh_area_offset %}
            {% else %}
                {% set area_max_y = safe_max_y %}
            {% endif %}

            {% set meshPointX = (meshPointX * (area_max_x - area_min_x) / (safe_max_x - safe_min_x) * probe_count_scale_factor)|round(0)|int %}
            {% if meshPointX < min_probe_count %}
                {% set meshPointX = min_probe_count %}
            {% endif %}
	    {% if meshPointX > meshMaxPointX %}
                {% set meshPointX = meshMaxPointX %}
            {% endif %}

            {% set meshPointY = (meshPointY * (area_max_y -area_min_y ) / (safe_max_y - safe_min_y) * probe_count_scale_factor )|round(0)|int %}
            {% if meshPointY < min_probe_count %}
                {% set meshPointY = min_probe_count %}
            {% endif %}
	    {% if meshPointY > meshMaxPointY %}
                {% set meshPointY = meshMaxPointY %}
            {% endif %}

            BED_MESH_CALIBRATE_BASE mesh_min={area_min_x},{area_min_y} mesh_max={area_max_x},{area_max_y} probe_count={meshPointX},{meshPointY} samples={probe_samples|int}
        {% else %}
            BED_MESH_CALIBRATE_BASE
        {% endif %}
    {% else %}
        BED_MESH_CALIBRATE_BASE
    {% endif %}

• (2) Go to slicer setting and replace the old bed mesh gcode the following command.

Prusa Slicer
BED_MESH_CALIBRATE AREA_START={first_layer_print_min[0]},{first_layer_print_min[1]} AREA_END={first_layer_print_max[0]},{first_layer_print_max[1]}

Ideal maker
BED_MESH_CALIBRATE AREA_START={print_pos_min_x},{print_pos_min_y} AREA_END={print_pos_max_x},{print_pos_max_y}

Cura slicer
BED_MESH_CALIBRATE AREA_START=%MINX%,%MINY% AREA_END=%MAXX%,%MAXY%

*(Cura slicer plugin) To make the macro to work in Cura slicer, you need to install the post process plugin by frankbags - In cura menu Help -> Show configuration folder. - Copy the python script from the above link in to scripts folder. - Restart Cura - In cura menu Extensions -> Post processing -> Modify G-Code and select Mesh Print Size

For user using single command START_PRINT

• (*) If you use single command start gcode like START_PRINT BED_TEMP={material_bed_temperature_layer_0} EXTRUDER_TEMP={material_print_temperature_layer_0} .You might need to add parameter parsing to BED_MESH_CALIBRATE inside START_PRINT. This is an example, also check my macro sample

[gcode_macro START_PRINT]
variable_parameter_EXTRUDER_TEMP: 190
variable_parameter_BED_TEMP: 60
; gcode parameters for area bed mesh
variable_parameter_AREA_START : 0,0
variable_parameter_AREA_END : 0,0
gcode:
    # preheat, homing, etc
    BED_MESH_CALIBRATE AREA_START={params.AREA_START|default("0,0")} AREA_END={params.AREA_END|default("0,0")}
    # the rest of your start macro here

And you will need to change Slicer start gcode to this

• Cura: START_PRINT EXTRUDER_TEMP={material_print_temperature_layer_0} BED_TEMP={material_bed_temperature_layer_0} AREA_START=%MINX%,%MINY% AREA_END=%MAXX%,%MAXY%
• Prusa slicer: START_PRINT EXTRUDER_TEMP=[first_layer_temperature] BED_TEMP=[first_layer_bed_temperature] AREA_START={first_layer_print_min[0]},{first_layer_print_min[1]} AREA_END={first_layer_print_max[0]},{first_layer_print_max[1]}