Prediction of Cutting Forces in Five-Axis Milling Using Feed Drive Current Measurements

This paper presents a model to identify cutting forces from the feed drive current measurements in five-axis milling processes. The friction, equivalent inertia, and the frequency response function of the structural disturbance of three translational (
X
–
Y
–
Z
) and two rotational (
A
–
C
) drives are identified. The disturbances caused by the structural modes are compensated through disturbance Kalman Filters for each drive. The kinematics of the five-axis machine tool is modeled using the Denavit-Hartenberg method and compensated motor current on the drives are transformed to the tool coordinate frame to obtain cutting forces. The application of the proposed method is demonstrated experimentally by machining a five-axis part on a Quaser UX600 machining center. LSV-2 communication protocol of the Heidenhain computer numerical control (CNC) is used to collect commanded, noise-free digital motor currents, drive speeds, tool center point position, tool orientation, spindle speed, and tangential velocity from the CNC via Ethernet connection.