Dynamic Characteristic Research Of Cnc Milling-Boring Machine

The main factors of influencing surface quality are attained by analyzing surface waviness of bored and milled sculptured surface. Cutting vibrations are an important factor which affects the quality of the workpiece surface. Cutting process and machine vibration system interact and interconnect with each other. Machine vibration system is mainly related to the structure. Study of structure of the machine tool and find the inherent characteristics can guide the design, reduce the machine's cutting tremor and improve the productivity of machine tools.Cutting force is an important parameter in the cutting process. It's the basis of researching'machine-tool'system, establishing milling simulation model and the dynamic analysis. Taking into account the complicated shape characteristics of ball-end milling, a simulation model of milling force is established reference to the research at home and abroad. The paper has elaborated the solution process of the model coefficient,programed computing software using MATLAB.It has finished the simulation of milling forces.The paper uses ANSYS to establish a finite element model of the TX6916 CNC milling machine.The form and the dynamic characteristics of real joint are discussed and theoretical calculation are applied to identify its dynamic parameters.Spindle and square ram system are the most important components of cutting.The paper uses ANSYS to establish a finite element model of bearing-spindle system and do the modal analysis. A finite element model of square ram is established and the non-damped free vibration is sdudied which obtains natural frequencies and its corresponding vibration modes.Dynamic response experiment with the method of hammer excitation is done to milling machine.Comparing test data and the results of finite element analysis of the spindle and square ram,the results verify the reasonableness of finite element model. Then the paper discusses the reasons for the error and provides proposed measures for improvement of the structure of milling-boring machine.It has carried out the transient dynamic analysis of the milling machine model with the simulation of milling forces. The relation between vibration displacement and cutting time can be depicted and the effects of ball-end milling vibration involved in the elongation of arbor and spindle has been sdudied.