A Novel Piezoelectric Grinding Dynamometer For Montoring Ultra-precision Grinding Of Silicon Wafers

It is necessary to monitor dynamic grinding force signal,dynamic characteristic of grinder and grinding performance of grinding wheel and real-timely realize adjustment in grinding wheel feed rate and other parameters,which can improve machining accuracy and surface quality of silicon wafers, guarantee processing yield.Grinding force is produced by grinding workpiece, and then transferred to the dynamometer. The dynamometer can feel and export the force.The movement is uniform between dynamometer and worktable. Relative to high-speed rotary motion of grinding wheel, the dynamometer translates or swings along with the worktable. It is a kind of passive measurement.This paper presents a novel piezoelectric grinding dynamometer, aiming at detecting demand of grinding force in the process of ultra-precision grinding. Grinder structure and interaction force distribution between grinding wheel and silicon wafers are considered.The piezoelectric effect is used.Four force sensors are used to measure three-dimensional orthogonal force simultaneously in the process.Soft ANSYS is used to design the dynamometer structure parameters,which can make the dynamometer work in the best condition.Four force sensors must have the same sensitivity, as well as the same co-rotating combined stiffness.The sensors are in uniform direction,homogeneous layout and arranged as a square in a circle on the base. The range of Fx and Fy is±500N, Fz is±1500N.The static and dynamic calibration devices are established,and the calibration of the dynamometer is done on the decive.Actual grinding experiments are done on grinder in the end.The results show the grinding dynamometer has high sensitivity, good linearity and repeatability, perfect static and dynamic performances, simple structure, non-centering, low cost, easy assembling and debugging, small zero drift.All specifications meet requirements of CIRP standards.