The Guaranteed Technology Of Availability Faced Life Cycle Machining Center

The development of Computer numerial controlled (CNC) Machine industry in our country is relatively laggard, and the availability is not high, which causes the share of homemade CNC machine in the market to be continuously very low. Statistics have showed that the market share is 24.3% in 2002,20.6% in 2003, 22% in 2004, and 21% in 2005. This situation is restricting the entire development of equipment manufacturing industry, and directly affecting the security of the national defense war industy. The developed experience of the domestic and foreign equipments manufacturing industry indicated that the CNC machine tool is a foundation in order to develop the equipment manufacturing industry. If the CNC machine tool would develop, the Machining Center is a key. Therefore, it is a earnest problem to carry out science development view comprehensively, speed up the development of our machining center industry, research the reliability and maintainability which can also say availability of Machining Center, enhances the availability level of the domestical Machining Center rapidly.1. The collection and analysis of availability tentative data of Machining CenterThe criterion of fault definition, fault judgment and fault count is confirmed firstly. The field fault data are collected and analyzed based on this criterion, gather 48 pieces of field fault data sampled from 19 series of Machining Center, find out the fault situation in the inspection time, and provide the basis for following fault analysis.2. Failure Mode Effects and Criticality Analysis (FMECA) Faced Life Cycle of Machining CenterThis chapter treats some serias of Maching Center as research object, analyzes the usability data obtained from loacal experiment of Maching Center, investigates the ratio thoroughly entire machine from various faults spot, fault pattern and the fault reason, graspes the whole fault situation of Machining Center, discovers the bigger affects of fault patterns to the entire machine reliability, analyzes the fault pattern and reason of the fault frequent part and subsystem to find out the direction of reliable improvement design, finds out weak tache of the Machining Center with criticality analysis in order to provide the gist for removing the fault of Maching Center. The fault situation of life cycle in different stages can be obtained from the fault anlysis of Maching Center, and provide the gist for life cycle in different stages established corresponding improving measurement.3. The Guaranteed Technology of Availability Faced Life Cycle of MACHINING CENTERAccording to analyze massive fault data system systematically and further, it was confirmed that many faults of some Maching Center is consanguineous relation to the life cycle stages of the design and development, manufacture and assembly, installation and debugging, locale running and maintenance and so on. Therefore, the practical feasible availability guarantee measures is taken to the life cycle of this series of production of Machining Center in different stage, in order to enhance the existing quality and the availability level of Machining Center. The keystone of availability is different in various stages of entire Machining Center life cycle.The stages of design and development mainly determine the various availability target of Machining Center with the help of fully considerating each kind of factor of entire life cycle, and then establish the official document, form the production standard of the Machining Center. The result of fault analysis shows that many faults are all directly or indirectly coming from the design reason in this series of Machining Center, therefore, the idiographic design rule and design method have been established in this stage, and provide the reference for the designers who can consider comprehensively and reduce each kind of faults in the process of design. Moreover, the problem of leakage which is caused by design is analyzed, and brought the advice of adopting special obturation. The broken problem of tank chain is also serious, bring forward the measure which can be solved accoding to stress filter experiment or simulation with the help of the user feedback data in the design stage. In the production stage, the parts of machinery and the electric appliance are producted, and each system is assembled. In this stage, each target of availability, which is not lower than the stated level established in design stage, is mainly ensued in the production process of system and equipment. The main working of availability must do many reliability and maintainence experiment, production experiment and reliable stress filter experiment, which can find the disadvantage factor promptly, take the guard measure promptly, avoid producting massive disqualified products, and reduce economic loss because of these reason.The stand or fall in the installment and debugging stage will affect the future working situation of Machining Center directly. The reasonable installment and correct debugging will ruduce occurrence of the fault, and improve the non-breakdown time in Machining Center. Therefore, the forepart performance test was adopted to find out the potential failure in Machining Center.In running and maintainence stage, the fault user reason statistics and unsettled fault situation in Machining Center showed that many faults were relation to the attitude, knowledge and skill level of operator directly. So the staff's training plan is established in this stage.The abandoned processing data of the Machining Center in this experiment was not collected, but the abandoned processing problem should be brought to the attention. It is suggested that some part of parts can be reclaimed and used reasonably under the environmental protection, and reduce the resources waste.All the safeguard measure in this article is united the analysis of the field test data in some series of Machining Center. But the problem existing in this series of Machining Certer is common, this method can also be used for reference in the other series of Maching Center.