State space model based reliability and sensitivity analysis for multistage manufacturing process

Quality is an important aspect of any manufacturing process. The stability of process is definitely one of the most important aspects to insure the quality of the machined part stably. Now it is still a challenge to put forward a useful model to deal with manufacturing process stability mathematically. This paper deals with the issue by the notion of manufacturing process reliability and its sensitivity. Based on state space model, process performance function which is used to describe the relations between key product characters (KPC) and key control characters (KCC) during machining process has been conducted. Furthermore, measurement index to process reliability is put forward, which leads the ways to calculate the process reliability mathematically. To determine the weakness during machining process, process reliability sensitivity has been put forward and the corresponding ways how to get its magnitude. Finally, A simple 2-D case study has been used to support and validate the proposed model. It shows that this way can calculate the process reliability effectively