On the Monitoring of Cutting Forces in End Milling Processes

Abstract

This paper presents a scheme to estimate cutting forces in end milling without using any additional sensors. An external disturbance can be estimated by monitoring the armature current in servo motors. It is, however, often subject to high friction on guideways, particularly in a stationary direction, which makes it difficult to estimate the disturbance in an accurate and stable manner. On the other hand, the armature current in a spindle motor is less affected by the friction, although only the tangential component of cutting force can be estimated. This paper proposes an estimation scheme of all the components of cutting force by geometrically combining force vectors given by servo motor and spindle motor currents. The accuracy and practical applicability of the proposed scheme are validated by experimental case studies, where the cutting force control for end milling processes is implemented based on the proposed estimation scheme.