Characteristic parameters of machine joints and the technology for applying them in overall modeling

There are various forms of joints in a machine tool, which have a high influence on the whole machine's static and dynamic behavior. Therefore the effect of the joints' features must be taken into consideration when establishing the overall kinetic model of a machine tool. Based on the forms of typical joints, the factors influencing the joint features are analyzed, and are classified into the factor of material, structure and application conditions; the expressing methods of the characteristic parameters for joints are presented for different sections based on the experimental results of joint features. During the establishment of the overall model for the machine, the characteristic parameters of joints are taken as known conditions, are equivalent to the connection rigidity and connection damp between structures, and added into the rigidity matrix and damp matrix of the dynamics model. The overall dynamics model of the machine generated therefrom covers the features of joints, and can more accurately predict the static and dynamic behavior of the whole machine. The correctness and effectiveness of the method is verified by the modeling and calculation of XK712B vertical boring and milling machine and comparing with the experimental results. With the method, it is possible to predict the static and dynamic behavior of the whole machine at the phase of drawing design.