Self-Sensing of Cutting Forces in Diamond Cutting by Utilizing a Voice Coil Motor-driven Fast Tool Servo

Abstract Cutting force measurement is important for monitoring the diamond cutting process. In this paper, a new measurement method of thrust cutting force associated with a voice coil motor (VCM) driven fast tool servo (FTS) system has been developed. Instead of integrating additional force sensors to the FTS which would influence the dynamics of the FTS, the force measurement in the proposed system is achieved associated with in-process monitoring the variation of the driving current of the VCM and pre-process determining the system parameters. In this way, the cutting forces are accurately obtained by subtracting the influences of the driving force, the spring force, the damping force and the inertial force associated with the system as well as the cutting process. Based on the proposed method, a microstructure array was machined using the developed VCM-FTS and the cutting force during the machining process was monitored in real time. The measured force signal was in good agreement with the machining result. The surface profile error of the fabricated microstructure could be clearly distinguished by the variation of the measured cutting force signal. This provides a new approach for in-process cutting force measurement associated with FTS based diamond cutting process.