Development Of Unitary Piezoelectric Four-component Cutting Dynamometer

Measuring forces and moments in cutting process is helpful to research cutting mechanism, calculate power consumption, and optimize cutting parameters as well as geometry parameters of cutting tools. According to changes of cutting forces, cutting process, such as wear or breakage of cutting tools, machine malfunction and so on, can be monitor. Therefore, cutting process can be controlled in time, cutting efficiency can be improved greatly, and rejection rate can be reduced.According to characters and varieties of forces and moments in cutting process, based on piezoelectric effect of quartz crystals, a type of unitary piezoelectric four-component cutting dynamometer is designed. Four sensors distributed as diamond on a ring are the core of the dynamometer. Horizontal moment and three-direction orthogonal forces carried on the dynamometer during cutting process can be measured simultaneously. Measurement ranges of the dynamometer is F_x / F_Y=- 5000～5000N, F_z =- 5000～5000N, M =- 200～200N·m. Using method of "force×force arm = moment", by using four crystal pairs, horizontal moment can be obtained easily and directly without complex calculation.In order to ensure the dynamometer being under the best working condition, structure parameters of the dynamometer are optimized by using ANSYS to choose the best values. Extreme working conditions in cutting process are discussed, and cutting ranges in which the dynamometer can work well are calculated.Establish static and dynamic calibration devices on which calibrations of the dynamometer are carried. The results show that the dynamometer has very good static and dynamic performances as well as high sensitivity, and all specifications meet requirements of standards of Scientific Technical Committees of CRIP-STCC. Finally, actual cutting experiments are carried on driller and lathe. They validate that the dynamometer with a stable performance can measure forces and moments non-centering, and zero drift of the dynamometer is very small.Therefore, the piezoelectric four-component cutting dynamometer has wide using fields which can measure forces and moments in drilling, grinding, milling and turning.