The Column Structure Of Ultra Precision Machine Tool Dynamic Characteristic Analysis And Optimization Design

Micro-nano machine tool which is a general term for nanofabrication equipment, represents a country’s highest level of industrial technology as well as the cornerstone of high-tech manufacturing industries, what is more important is that it determines the core competitiveness of the country’s overall manufacturing industry and which also has an impact on people’s livelihood of the country. NVG-300micro V-groove ultra-precision machine tools is mainly used to process micro V-groove, micro cylindrical tank, light guides, backlight module, dicing and other ultra-precision machining. It requires X, Z axis precision0.5μm and Y-axis accuracy under lμm, the roughness of surface less than0.01μm, the spindle’s runout accuracy below0.1μm. This kind of processing equipment is widely used in national defense, aviation, aerospace and other fields of micro-electronics, which is the basic equipment for processing the high-tech products. There is little foundation of China’s micro-nanofabrication equipment’s level and dynamic design, which mainly rely on experience in design, prototype, installation, and structural modifications. Moreover, the cycle of development is long and the design method is difficult to meet the demand of high-speed, high-precision processing. Therefore, in order to develop a reasonable structure, high precision, low vibration, and low-cost micro-nano machine tool in a more efficient way, we must apply the advanced CAE technology for dynamic analysis of micro-nano machine tool’s structural and dynamic parameter’s optimization techniques.Column structure is one of the dominant parts of the machine tool. Its dynamic performance directly affects the micro-nano machine tool’s accuracy. This article focused on the column structure of NVG-300micro-nano machine tool to make research and analysis. We use the method of finite element analysis for dynamic analysis and dynamic column parameter optimization, for the purpose of improving the dynamic stiffness of the micro-nano machine tool. This paper’s cardinal research work is building parametric CAD modeling of micro-nano machine tool’s column structure, the column structure’s dynamic analysis (modal analysis and harmonic response analysis) and modal test (because of the current conditions,we only carry out the testing program), as well as the dynamic parameters of the column optimization (established the response surfaces, sensitivity analysis, multi-objective optimization).The innovation of this paper is mainly reflected on the following sections:(1) Make analysis by combining static with dynamic methods for micro-nano machine’s column. Firstly, static analysis is made for column structure under the condition of imposing on the column bolt preload, also on the basis of the machine modal analysis and harmonic response analysis. We will achieve dynamic stiffness parameter of the column under the action of the grinding force at the grinding points.(2) The size of the whole column structure is optimized. The design size structure is set as design variables, and central composite experimental design using finite element method establish the optimal design of the sample. In addition, all these are solved respectively.(3) The relationships and response surface model are built between study design variables and target variables through response surface methodology.(4) By using multi-objective genetic algorithms, the structure of the column is optimized, getting a set of pareto solution. In this way, weighing the relationship of setting goals between variables, the best design can be established. Meanwhile, adopting sensitivity analysis can gain the round number of design variables, in order to design and process conveniently. After rounding the dynamic analysis of the column, the final dynamic parameters can be achieved.After optimization the quality of the machine column did not increase, the machine tool firstly-order and second-order intrinsic mode significantly improved, effectively improve the stability of machining, the more important is that the grinding point and relative vibration displacement between the workpiece significantly reduced, in theory, increase the stiffness of the machine tool and the workpiece between the grinding points, improved machine tool precision.