Study On Dynamics Characteristic Of Joints Of Ultra-high-speed Surface Grinder Functional Parts

Ultra-high-speed surface grinder is an important modern processing equipment. With thedevelopment of the technology of high cutting speed, high feed rate and high precision, theprocessing requires the modern machine tools and equipment has not only good staticproperties, but also excellent dynamic performance. Joints of machine tools has a greatinfluence on static and dynamic performance of the whole machine. Studying on the effect ofjoints on machine performance, and using the foundation parameters of joint to design themachine can improve static and dynamic performance of the machine and shorten thedevelopment cycle.Starting from analyzing the structural characteristics of the whole ultra-high-speedsurface grinder machine and each subsystem, the characteristics of the system of the typicaljoints with theoretical analysis, the relationship between static displacement and force in theplane joints is gotten, and the stiffness and damping are calculated. Using the joints dynamicsmodel in screw and pin connection portion, a dynamics model of both pin and screwconnection is derived, which leads to computational dynamics including stiffness anddamping of the joint between column and its seat. Based on the normal and tangentialstiffness of linear motion guide, the axial stiffness of ball screw and angular contact ballbearings, the dynamic model of joint of ball screw linear rail is founded. The approach oftheoretical modeling of the joints surface in machine on the basis of the spring-damping unitis studied to set the units’ stiffness and damping according to the joint surface stiffness anddamping obtained by theoretical analysis method, which modal and harmonic responseanalysis need to analyze the column and the column seat systems, table rails system withANSYS.The study shows that the natural frequency of the column and the column seatsystem and the table guide system using flexible processing calculation is lower than thatusing the rigid, and the former is closer to the actual results.Under the influence of the joints stiffness parameters, the dynamic characteristics of thesystems are analyzed, while the joint plane stiffness which has a large effect has beenimproved. After optimizing the joint surface parameters, the natural frequency of the systemeach mode is improved in varying degrees, while the system vibration amplitude is reduced,grinding vibration is suppressed, the system static and dynamic characteristics is effectivelyimproved.