Development of an Ultrasonic Sensor for In-Process Measurement of Workpiece Diameter in Bar Turning

Abstract The paper presents the development of a novel non-contact sensor for on-line measurement of workpiece diameter in bar turning while using cutting fluid. The proposed measuring system allows continuous high speed monitoring of the workpiece absolute diameter. An algorithm is developed to simultaneously compensate for sensor misalignment due to translation of the rotation axis under the effect of dynamic cutting forces. The sensor employs three ultrasonic squirter transducers. It is designed to provide high accuracy, and practical working range, in addition to compactness and robustness, so that it can be incorporated into a numerically controlled turning machine. The accuracy and repeatability of the measuring system were tested experimentally under realistic cutting conditions. Comparison of the sensor measurements with those obtained from a CMM showed good agreement.