External axes parameters
Robot controller can use external axes and it is necessary to assign correct positions (indices) for that axes in assembly. Default SprutCAM postprocessors use index-based axes identifiers (ExtAxis1Pos for first axes, ExtAxis2Pos for first axes and etc). Some of custom postprocessors can use also axes address instead of indices (E1, E2, E3, J4 etc).
Click 
button to open Assembly parameters panel. Then go to the Axes tab.
Define Address and External axis position (index) here. MachineMaker will show axes identifier (like ExtAxis3Pos) in tooltip. You can use it in postprocessor.
Axis address and axis index must be unique in assembly context. You you are trying to set already in use value, MachineMaker will propose to replace existing one.
It is not possible to change robot axis address and index. It is necessary to change external addresses only.
It is also possible to define additional axes parameters here: Control type (Continues, Indexed, Manual), Brakes and Shortest path rotation mode