The Synthesis Of Reliability Analysis Of Horizontal Machining Center

Domestic machining center has a certain gap compared with foreign processing center in the level of manufacturing. The main reason is that the reliability level is not high, and the failure rate is too high. With the continuous development of the domestic auto industry, the demand of machining center is increasing. Therefore, to improve the reliability of the machining center is an urgent problem need to be solved. To improve the reliability of the machining center can not only expand the domestic market share and improve the export advantage of domestic machining center, but can also develop the level of the whole China' machinery manufacturing industry.Firstly after having the reliability evaluation test of the HDL63 machining center in cylinder production line, the failure data of eight HDL63 processing center which run for 11 months was collected. At the same time, the Reliability Enhancement Testing of the main components of the machining center is conducted. Acceleration factors that can greatly stimulate failures of machining center were selected and a comprehensive stress profile of the testing was developed. Finally, applying the FMECA method the fault data were classified into different failure modes and the critical harm values were calculated. According to the results of the FMECA the failure mechanism of machining center was analyzed deeply, which can provide guidance for improved design of the machining center.Accurate reliability model can correctly describe the reliability change trend with time of machining center, this paper aimed to improve the precision of model fitting. Because the failure rate curve of machining center showed the same change trend of the'bathtub curve', a new bathtub curve was used for fitting fault data of HDL63 machining center. At the same time use the commonly used Weibull curve were fitted the fault data of HDL63 machining center. At last, through comparison of the two curves' fitting accuracy squared error (MSE) of the bathtub curve fitting were smaller than the parameter of Weibull fitting, so the bathtub curve fitting has a high precision.Then based on analytic hierarchy process the reliability allocation design of the HDL63 machining center on the cylinder block production line was conducted. Firstly the mean time between failures (MTBF) was determined as the index of reliability allocation. Then the four distribution criteria which has strong influence on the reliability allocation was determined, including the fault frequently, the harm fault, the maintainability and the cost efficiency ratio. The fuzzy matrix and the membership degree vector of criterion layer was calculated. Finally the allocation reliability index of each function subsystem were calculated.Finally using the Sipesc platform a reliability synthesize analysis software aimed at machining center was compiled. The calculation process of the above three chapters was translated to algorithms diagram, then according to the algorithm diagram the reliability analysis software was programed. Three Calculation functions of reliability synthesize analysis software were reliability modeling function, FMECA fault analysis function and reliability allocation design function respectively. After inputting fault data into the databases of reliability synthesize analysis software the calculation results of software were confirmed to be truth. Reliability synthesize analysis software simplifies the artificial calculation process, and saves a lot of time and manpower for the management and analysis of the machining center' reliability.