五轴联动精密微铣削机床试验模态分析

Experimental modal analysis of five-axis precision micro-milling machine tool

五轴联动精密微铣削机床的结构性能直接影响精密三维微小零件的加工质量,为研究其结构性能,应用试验模态分析技术对五轴联动精密微铣削机床进行结构分析。采用单点激励多点响应的方法进行锤击试验,建立传递函数,经分析处理得出机床固有频率、阻尼比与振型等动态特性参数,并对识别的参数进行模态置信矩阵(MAC)校验。试验得到机床前三阶固有频率为102.44,133.97,154.86 Hz,对应阻尼比为3.27%、4.94%、2.14%;试验结果证明该五轴精密微铣削机床结构布局合理,机床固有频率有效避开微切削加工的激振频率,通过振型分析可找出机床结构薄弱环节,并提出优化建议。试验验证应用试验模态分析技术对机床动态特性分析方法的有效性。

The performance of five-axis linkage precision m icro-m illing machine tool structure hasdirect influence on the quality of machining 3D precision micro components. In order to study theproperty of the machine tool structure, it was analyzed with experimental modal analysistechnique. The hammer test was conducted by the method of a single-point excitation and m ultipointresponse, and the transfer functions were set up. Dynamic characteristic parameters of themachine tool structure including its natural frequencies, damping ratios and vibration modes wereobtained by the analysis and processing. Also, the modal parameters were verified by the modalassurance criterion (MAC). The first three of the natural frequencies obtained by the experimentare 102.44 H z, 133.97 Hz and 154.86 Hz and the corresponding damping ratios are 3.27%, 4.94%and 2.14%. The experiment proves that the structure of the five-axis linkage precision micromillingmachine tool is reasonable and the natural frequencies can effectively avoid the vibrationfrequencies of the micro cutting process. The weak links of the machine tool structure werediscovered by the analysis of the vibration modes. Optimization suggestions were put forward. Itproves that the experimental modal analysis technique for studying the dynamic characteristics ofthe machine tools is effective.