Dimensional Quality Oriented Reliability Modeling for Complex Manufacturing Processes

The stability of process is certainly one of the most important aspects to fulfill the task. Now, it is still a challenge to put forward a model to deal with the stability of manufacturing process mathematically. Aiming at solving the problem, this paper discusses the issues by the notion of manufacturing process reliability and its sensitivity. Based on state space model, the process performance function which is used to describe the relations between the key product characters (KPC) of the machined part and the key control characters (KCC) of multistage process in machining system has been built. Furthermore, the measure index to the process reliability of multistage machining system is proposed, which facilitates the forming of the ways to model the process reliability mathematically. To determine the weakest stage during machining process, the sensitivity of process reliability to KCC of the process has been put forward and the corresponding ways how to calculate it. Because of the multistage process is highly non-linear process, chaos optimization algorithm and mutative scale chaos optimization algorithm are used to calculate this kind of robust reliability index. Finally, A simple 2-D case study has been used to validate the proposed model. It shows that the process reliability can be calculated effectively.