The Dynamic Characteristic Research Of Milling And Grinding Machine Key Parts

With the rapid development of production and technology, machine tools are increasingly developing in the direction of high speed, high efficiency, high precision and automation. Besides the requirements of lightweight, low cost, easy to use and good manufacturability, the focus on more and more high processing machinability is highly claimed. Research shows that the processing quality mainly depends on the vibration that machine tools operation cause. Especially for the machine tools with the high speed and high accuracy, the influence of vibration on the machine tools is more remarkable. Therefore, the vibration machine tools operation cause is the primary issue of the dynamic characteristics research. Then, the dynamic characteristics of machine tools have closely related to the dynamic characteristics of their components.The bed is the foundation of machine tools,which plays an important role in sustaining the components like the workpiece, spindle box and tail stock, whose dynamic characteristics are related to whether machine tools working safely or not and the service life of the whole machine. The unnecessary loss that resonance factors cause will be avoided in the process when the stiffness characteristics of the bed structure are studied. As an important movement part, spindle system involved in grinding directly, which exerts an influence on the machining precision of machine tools, grinding ability, surface quality and productivity. Therefore, it is necessary to analyse the dynamic characteristics of the bed and spindle system in detail. The main work and contributions of mis dissertation are listed as follows:(1) With the COMBIN14unit to simulate the elastic support of spindle bearing, the finite element dynamic model of spindle system was established in ANSYS, and the corresponding static and dynamic characteristic analysis were carried out. And the dynamic characteristic influence of the preloaded force being exerted in the bearing on the rigidity of spindle was discussed. The simulation results show that the high-speed wheel spindle discussed in this thesis can satisfy the design requirements;(2) The three-dimensional solid model of milling and grinding machine bed was established based on the CAD software Pro/E. The finite element dynamic model of the bed was achieved with the help of ANSYS Workbench12in which the modal analysis was carried out to get the natural frequencies and vibration modes;(3) A test modal analysis platform of the bed was built based on the LMS vibration test system, with the response of the measured points that the LMS multi-channel acquisition equipment collected and data analysis and processing from the LMS Test. Lab9A modal analysis software, finally the modal parameter identification was achieved. Comparing the results from the finite element modal and the test modal analysis modal, the rationality of the finite element model of the bed was verified which provided the basis for further dynamic analysis and optimization design of the bed;(4) According to the dynamic characteristics research of the bed, the improvement program was proposed. Structure optimizing design of the bed was carried out by the Design Explorer module in ANSYS Workbench12to achieve the improvement of the lightweight improvement of the bed.