Design and development of a cutting force sensor based on semi-conductive strain gauge

A kind of cutting force sensor based on semi-conductive strain gauge is proposed in this paper in order to optimize the contradiction between sensitivity and natural frequency of strain-gauge type sensors. A new sensing element of two mutual-perpendicular octagonal rings¹ (TMPOR) is developed to improve natural frequency; and semi-conductive strain gauge that fabricated by MEMS (micro-electro-mechanical system) technique is used to enhance sensitivity of the sensor due to its higher gauge factor (GF). Static calibration experiment results show that semi-conductive strain gauge has improved the sensitivity by 16 times than traditional metal foil strain gauge, which proves the feasibility of settling the contradiction aforementioned by using MEMS technique. Modal impact test indicates that the natural frequency of the fabricated sensor is 771 Hz in primary direction, which fulfills its most application in high speed machining process. During dynamic cutting force measurement test, the developed sensor exhibits satisfying ability in dynamic cutting force signal detection. Generally, the MEMS technique based sensor shows great potential in solving technical defect between sensitivity and natural frequency in current cutting force sensor research.