Failure distribution law of a machining center and its study

The reliability study for numerical control (NC) machine tool is of significance to increase the market share of the NC machine tool. The mean time between failures (MTBF) of NC machine tool is an important reliability criterion; however, the failure distribution law, as the basis for calculating the MTBF, has not been adequately studied. Based on Type-Ⅰcensored likelihood function and actual timing censored data of the machining center, the fitting of weibull model is made for time between failures of machining center, then goodness-of-fit test is performed by the Hollander-Proschan's method. In the end it is proved that the time between failures of the machining center follows Weibull distribution. It is very effective to make fitting with censored likelihood function and goodness-of-fit with Hollander-Proschan's method for these censored data.