Accurate modeling and controlling of weak stiffness grinding system dynamics with microstructured tools

Abstract

The weak stiffness grinding system often produces uncontrollable vibration, which directly reduces the machining quality. In order to accurately predict and control the weak stiffness grinding system dynamics, an accurate dynamics modeling and the controlling method with microstructured tools are presented innovatively. Based on the real random abrasive grain model, an instantaneous undeformed chip thickness model considering the phase deviation, time accuracy and grinding wheel-workpiece separation caused by vibration is established. On this basis, the controlling principle of microstructured grinding wheel on chip formation mechanism and grinding forces is studied. Then, combined with the element division principle and dynamics parameters of grinding system, the dynamics model of weak stiffness grinding system is established. According to the grinding experimental results based on vibration monitoring, the error rate of the established dynamics model is less than 9.8 %. Compared with the non-structured grinding wheel, the microstructured grinding wheel can control the vibration amplitude, the vibration frequencies and the wheel deflection. Based on the workpiece surface machining results, the addition of microstructures suppresses the phenomena of overcutting and the wheel bounce, and the profile protrusion height caused by grinding vibration is decreased by 77 %. The established dynamics model is of great significance for understanding and control the dynamic behavior of weak stiffness grinding systems.