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Workpiece: [Probing] [Height map]
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Probing uses the G38.3 command to detect the contact of the tool with the workpiece. By default, grbl detects a contact to ground on Pin A5, which means, the cutter / probing-tool is connected to ground (because it is perhaps already connected to ground via the spindle and support) and the touch-plate is connected to Pin A5.

General settings are:

  • Probe / cutter diameter: needed to calculate offsets, if 'Set tool center as zero' is enabled.
  • Touch plate dimension: thickness of touch-plate or aluminum-tape, needed to calculate offsets.
    If a conducting workpiece is used, these values needs to be set to zero.
  • Probing feed rate: speed of the probe when moving toward the edge.
  • Max. Probing distance: range / distance to move to find the edge.
  • Save distance: distance from edge to move to finally - after resetting the coordinates.
    Must be higher than touch plate thickness.
  • Use G10 L2 P0: sets the actual coordinate system after successful probing.
  • Use G92: set the coordinate system offset instead.


Edge finder

With the edge finder an edge in X, Y, X and Y and additionally in Z can be found and used to set the work coordinates to zero.
If more then one edge should be found, the order is as visible in the graphics: first '1' then '2', finally Z. 

Place the tool tip in front of the workpiece in the same area in which the arrow tip is shown in the graphic.

If an edge is found two times (vertical or horizontal) an angle will be calculated, which can be used to rotate the G-Code.


Center finder

With the center finder, the center of a drill or or round workpiece can be found.

Workpiece diameter: needed if the outside contour is selected, to move above the workpiece far enough from position 1 to 2 to 3 to 4.





Tool length

Tool length correction is a bit tricky:

  • 1st get the tool length of the first tool
  • Then zero the Z position via G92 as needed
  • Start work
  • After a tool change, measure tool length of new tool


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