Study On Dynamic Modeling For Gantry Machining Center Beam Components Structure And Prediction Of Chatter Stability

With rapid development of modern manufacturing industry, it has brought unprecedented opportunities and challenges for machine tools equipment industry. Machine tools use various cutting or forming way to produce machinery parts. In order to guarantee the processing of a specific tolerance, machine tools precision must be higher than the precision of machining parts, machine tools accuracy depends mainly on the dynamic behavior of machine tool structure. To study dynamic behavior of machine tool structure must analyze dynamics of machine tools structures. In the past, machine tools physical prototype was tested to get the structure dynamic characteristic parameter data, and then process it to complete dynamic analysis of machine tool structure. But, today development and application of finite element theory make it real to establish virtual prototype of machine tools, then simulate the dynamic characteristics in a virtual environment.The dissertation combined with design of DF5020 gantry machining center beams components structure, characteristic parameters and dynamic model of join was focused, dynamic model of beam components structural was built in finite element environment, using finite element method to predict on low-speed and heavy milling chatter stability for gantry machining center beam components. The research take some practical significance on promoting the development of machine tool industry. The main research work falls into the following points:(1) Linear guidance joint stiffness is calculated with analysis theory of contact stiffness of bearing in the dissertation, and the dynamics model of linear guidance joint was established. It used the modal identification method to test the dynamic characteristic parameters of the linear guidance joint, and proved the feasibility of theoretical rigidity calculation methods. The dissertation proposes a theoretical method to calculate stiffness of ball screw joint with pre-load and the dynamic model of ball screw joint was established.(2) The co-simulation based on Pro/E, Workbench and Classic Ansys proposed to overcome the limitation due to using single simulation platform in the dissertation. It was established that finite element model of the beam components structure combined linear guide and ball screw joints dynamics characteristic parameters, and carry out more in-depth simulation and analysis.(3) The dissertation combined finite element analysis machine tools structure and milling chatter analytical theory based on the Altintas and Budak's approach, and proposed prediction on chatter stability of machine tools based on finite element method, we called that finite element prediction on the machining stability of machine tools structure.(4) The dissertation uses similar principles of experimental to design similarity gantry machine tools beam components test platform. It is prepared to study related experimental with dynamic modeling for machine tools structure and the method for prediction on chatter stability.