Response Of Ultra-precision Machine Under Micro-environment Vibration

Precision and ultra-precision machining technology, concentrating on the machining accuracy, is the foundation of modern high-tech industry, as well as the symbol of comprehensive national strength. While the main factor decreasing the accuracy in the process is micro-vibration. Taking an ultra-precision machine tool as research background, the following aspects are mainly studied for the research of the response of ultra-precision processing equipment under environment vibration in this paper:(1) the characteristics and effects of micro-vibration on the ultra-precision machining accuracy are analyzed to put forward theory methods to the solution of micro-vibration;(2) the intrinsic characteristics of the ultra-precision machine is obtained by experimental modal analysis, and the limited value of displacement is concluded by the dynamic response of vibration;(3) the theory model of processing machine is verified through the modal analysis contrasted with the test results, providing essential conditions for the subsequent researching;(4) the influences of the overall design and key parts of the machine on machining accuracy are studied, and through numerical simulation analysis in ABAQUS of the vibration response in the table and the cutter caused by machine spindle working at different speeds, and results show that the influence of spindle working is remarkable, with displacement larger than allowed limit, among which the response is relatively small at speed of390r/min;(5) time and frequency domain response of processing machine under measured environment vibration is explored, with acceleration histories as excitation in time domain analysis and acceleration power spectrum in the other. Through modal dynamic analysis and PSD analysis, the results of peak response in time domain and the mean square value of displacement in frequency domain cannot meet the requirement of50nm limit, espacally in X and Z direction, as is necessary to take measures for vibration;(6) considering base isolation, the dynamic response of processing machine under micro-vibration is significantly reduced than before, which can satisfy the limit requirements; and isolation rates in X and Z reach as high as90%. At the same time the response varies with the base thickness and spring stiffness for isolation changing, and the results show that suggested base thickness value in standard is conservative, while too large value could lead to reduction of vibration isolation. In addition, with the spring stiffness increasing, the response of displacement can be reduced, significantly in X direction;(7) when the spindle working at390r/min, the response of displacement caused by spring stiffness changing is discussed in vibration isolation system. Overall, the response in X direction changes significantly, and variations in Y and Z are relatively small; when the spring stiffness is3.5×104N/m, the response is larger; and despite the drop of displacement, it still needs to be improved after vibration isolation compared to the ideal value of displacement.Through the research content above, the level of influence of micro-vibration on ultra-precision processing machine is mastered, and also trial and research of vibration isolation is made to propse design recommendations for engineering applications.