Study On The Replacement Of Key Components Of Machining Center

Failure of a key component of machining center may lead to the whole production line suspended in the process of working, which may causing great losses to the enterprise. It is very important to replace the key components timely in order to ensure the continuous working of machining center. Therefore, considering multiple factors to optimize the replacement time of key components becomes the focus of current research.In this paper, we take a certain type of domestic machining center as the research object based on the National Nature Science Foundation. Combine with the failure information, analysis work of collected data is carry on with the help of mathematical statistics theory. The reliability modeling of the machining center and its subsystem will be carried out on the basis of the Total Failure Time Method, and the reliability influence degree of the subsystem can be quantified in succession. According to the different type of key components, different optimal replacement time models will be proposed to balance the production cost.The main contents are as follows:(1) Failure data analysis of machining centerTest the failure data of machining center for outliers based on the mathematical statistics theory, which can ensure rationality and reliability of the failure data. After the test for outliers, Weibull process model is established to inspect the shape parameter and scale parameter of multiple machining center Weibull process models with the help of AMSAA model theory, which can ensure the same type of the multiple machining center and eliminate the distortion phenomenon caused by taking all failure data together to analysis. At the same time, this work will provide a reliable data basis for reliability modeling.(2) Analysis of reliability influence degree of machining center subsystemFailure data integration of the same type machining center is carried out at the basis of the total failure time method, and the reliability function of the machining center can be obtained since its reliability model established. The reliability model of the subsystem of machining center is established then, in order to guarantee the accuracy and reliability of modeling under small-sample case, the non-offset estimation formula of parameters, which based on the maximum likelihood estimation is used for correction. To quantified the reliability influence degree of machining center subsystem, the concept of dynamic reliability influence degree and dynamic core reliability influence degree is used in this paper.(3) Determination of replacement time of the key components of machining centerFor key components of different failure mode of machining center, effective failure rate and ultimate failure rate are given in this paper. Combined with the cost of failure, maintenance and replacement cost information, the optimal replacement time models of key components of different failure types are established, then, the optimal replacement time at which the unit cost is the lowest can be obtained.