Papers by Author: Xiao Cui Zhu

Abstract: A method is introduced to process the failure data of 12 sets of machining centers for modelling and analyzing their reliability. In this method, Matlab is applied to fit the failure data for getting a hypothesis that their time between failures obey weibull distribution. Then, MLE (maximum likelihood method) is used to estimate parameters of distribution model of the time between failure, and the K-S test is employed to test the above hypothesis for proving that time between failures of machining center obey weibull distribution. Finally, the analysis of their common failures and corresponding improvements are done, which provide the theoretical basis for improvement of reliability of machining center and are greatly valuable in engineering.

Abstract: A method is introduced to analyze the reliability of wire cut electrical discharge machining by using the the failure data. It requires the least square method to estimate the parameters of the distribution model of the time between failures, utilizes the K-S test to test the hypothesis which distribution the reliability data obey, analyzes the common faults, and gives improvement approachs. Results show the fact that the time between failures obey thelognormal distribution, which provides the theoretical basis for improving the reliability of wire cut electrical discharge machining and have important application value.

Abstract: This paper chose multi-index to provide a comprehensive evaluation model to evaluate the use reliability of CNC machine tools as a single assessment indicator is biased. As the number of evaluation factors is huge and it is difficult to get the exact values, a fuzzy theory is applied. Reliability mathematical model and maintainability mathematical model were established based on failure data selected from filed test and calculated the estimation values of reliability indexes. Subsequently, a fuzzy comprehensive evaluation mathematical model of CNC machine tools was constructed which combined fuzzy with comprehensive evaluation theory. Using this model could evaluate reliability level of CNC machine tools accurately and integrative.