The Study Of Dynamic Characteristics Of Horizontal Machining Center

The dynamic characteristics of NC machine tool have an important influence onmachining accuracy, efficiency, the surface quality of parts and other properties,however the dynamic performance of domestic NC machine tool is weak. Supportedby the National863project, the study of experimental modal analysis, finite elementmodeling and damping characteristics is carried out for the horizontal machiningcenter of BEIJING PRECISION MACHINERY&ENGINEERING RESEARCHCO.LTD, which aims to break through the key technology of the machining center’sdynamic design, and provide an effective basis for positive design of the machiningcenter.The main research work of this paper includes the following aspects:(1) The dynamic characteristics of the machine tool are identified and the weak linkof the structure of machine tool is found by Modal analysis experiment analysis,in which the machine tool is excited from X, Y and Z direction using B&Kdynamic test system.(2) The dynamic model of the machine tool is established by the finite elementsoftware ANSYS, considered the boundary conditions and the combinationsurface equivalent, the validity of which is verified by experiment result, and thesimplification principles of the model are got in the meantime.(3) Based on the established dynamic model, the parameters of harmonic responseanalysis are determined and the harmonic response analysis is carried out to thehorizontal machining center. Based on the dynamic flexibility of machine tool, theinfluence of material and joint surface damping on the dynamic characteristics ofthe machine tool is analyzed, and the influence of joint surface stiffness on thedamping characteristics of the joint surface is also analyzed.(4) According to the structure characteristics of horizontal machining center, jointsurface research model is designed and experiment is carried out to study thedamping characteristics of the joint surface. Based on the research model, theinfluence of pre tightening force and surface roughness on the parameters of thejoint surface is analyzed. The study of experimental modal analysis, finite element modeling and dampingcharacteristics provides some guiding significance to the positive design for theprecision horizontal machining center, and promotes the design level of dynamiccharacteristics of NC machine tools.