Reliability Growth Techniques Of CNC Machine Tool

It is pointed out that the reason of lower market participation of popular NC machine tools made in China is the lower reliability. The reliability has become "bottleneck" of technical development of numerical control system, and has become the importantly common and key technique of the whole NC equipment and even now machine manufacturing development. The most important quality standard of NC machine tools is the using reliability (weighed by MTBF). There is great distance between homemade NC machine tools and the overseas famous products, so it is very significant to carry on the research of the NC machine tools reliability growth technique and to enhance the competition ability of homemade products. This essay is a part of the Hi-Tech Research and Development (863) Program of key reliability technology development and application of CNC device and system. The main point of this essay is the research of the NC machine tools reliability growth technique, which is order to achieve the significant reliability growth by applying these techniques.Researched the reliability of NC machine tools deeply and based on the traditional reliability growth management mode, the author put forward the life-cycle reliability growth management mode for NC machine tools. The traditional reliability growth management regards the reliability target value as the function of time and other assets and reallocates the assets based on the reliability comparison of plan value and estimate value, then control the pace to get the reliability target value. TAAF process management is the mode carried on during product development stage, trial-produce stage and batch produce stage, but the using stage hasn't been referred to. The author put forward the life-cycle (including the product development stage, trial-produce stage, batch produce stage and the using stage) reliability growth management mode which is added the CAAF (collection, analysis and fix) process management to the traditional management mode.Based on the failure date during the using stage of some type NC machine tool, the author choose the AMSAA-BISE model to track and evaluate its reliability growth. The point estimation and interval estimation of MTBF at the moment of test end are got. The author also predicts the time interval that the next failure will happen, in order to provide maintenance in time. Based on the production of other graduate students, the author introduces the reliability growth techniques applied in different stage and establishes the early failure test criterion and reliability assurance measures of key working procedure, key assemble process, key components and outsourcing parts. The reliability design criterion of NC machine tools is also established based on the design experience and collection of failures during using.