Mechanical interface coordinates

The mechanical interface coordinates refers to 3-dimensional Cartesian coordinates whose origin is at the center of the flange surface as shown as show below. The X,Y and Z axis in mechanical coordinates are expressed as Xm, Ym, and Zm.
The figure below represents VM robots.
For other robot types, the size of orientation key hole is φ5H7.

Zm: Normal axis on the center of the flange surface Ym: Axis passing through the flange center and orientation key hole Xm: Axis passing through the flange center and crossing Zm and Ym at right angles

Unlike the work coordinates or base coordinates, the mechanical interface coordinates rotate as the robot flange rotates.