What are Plane Selection G-Codes (G17, G18, and G19) used for?
It’s convenient to refer to planes for various purposes. A plane is a flat 2-dimensional space defined by two axes. For example, the default plane on most mills is XY. If you draw an arc without specifying a change in the plane, it will be drawn on the XY plane. There is a plane for each combination of the linear axes XYZ.
The G17, G18, and G19 G-Codes select which plane is active.
G17: XY
G18: XZ
G19: YZ
Here is a visual representation of the planes:
Plane selection is modal, so once you have established a plane all future arcs will be against that plane until a different plane selection g-code is invoked.
The selected working plane affects the following commands:
G43/G44: Cutter length compensation. Length compensation is along the axis that is perpendicular to the selected plane.
Many canned cycles.
It’s a good idea to include a plane selection gcode such as G17 in the preamble or safety block at the top of your g-code program. Most g-code operates in G17 mode and you will seldom use G18 or G19.
Example Use: Right Angle Heads on Milling Machines
G18 selects the XZ plane. The active plane determines how the tool path of an arc is interpreted.
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![G17, G18, and G19 G-Codes [Plane Selection]](data:image/svg+xml;nitro-empty-id=NDgzOjEwMzk=-1;base64,PHN2ZyB2aWV3Qm94PSIwIDAgOTg4IDY3NSIgd2lkdGg9Ijk4OCIgaGVpZ2h0PSI2NzUiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PC9zdmc+)
![Program Stop and End G-Codes [M00, M01, M02, and M30]](data:image/svg+xml;nitro-empty-id=Nzc0OjUzMTM=-1;base64,PHN2ZyB2aWV3Qm94PSIwIDAgMTUwIDE1MCIgd2lkdGg9IjE1MCIgaGVpZ2h0PSIxNTAiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PC9zdmc+ "Program Stop and End G-Codes [M00, M01, M02, and M30]")
