Reliability analysis for series manufacturing system with imperfect inspection considering the interaction between quality and degradation

Reliability evaluation of manufacturing system always takes machine performance and product quality as two key factors. But the imperfect inspection usually leads to unreliable quality judgments, cause the propagation of unqualified products, and aggravate the degradation of downstream machines. In this paper, considering the effect of imperfect inspection process, a new reliability model is developed based on the interaction between machine performance and product quality. Firstly, multiple degradation modes, which include continuous and discrete degradations, are modeled by different stochastic processes. Secondly, a quality reliability model is established to evaluate the satisfaction rate of production demand based on the variation estimation model of product's dimensions. Thirdly, the four states (Q-Q, U-U, Q-U, and U-Q)of quality inspection process are defined, whose effects on discrete degradation are analyzed in qualitative by referring to the quality evaluation. Finally, a system reliability evaluation model is proposed based on the analysis of minimum target requirements, and the practical case of a connecting rod illustrates the effectiveness of the proposed model. The results indicate that the abundant information existing in manufacturing system can be effectively integrated and exploited by the proposed reliability model, and the weakness of manufacturing system can also be identified easily.