For CNC, precisely maintaining the path to the predefined velocity is priority. The machinery is assumed to be capable of fulfilling these specifications, and therefore that the machery can tolerate the resulting velocities, accelerations, and moments.
For PTP (point-to-point) motion, maintaining the path is secondary. The motion in the axis space is defined by waypoints and the motion is interpolated between these points. For this purpose, the velocity and acceleration limits of the axis taken into consideration.
For CP movements the kinematic follows a programmed path. In contrast to CNC the velocity, the acceleration and the jerk limits are considered. Under these conditions the path is followed as fast as possible.
The calculation of PTP motion requires only one cycle so that movements can be planned or changed on the spot. The calculation of CP motion is more complex and generally requires more than one cycle.
See also
