Process capability monitoring chart with an application in the silicon-filler manufacturing process

Process capability indices (PCIs) can be viewed as effective and excellent means of measuring product quality and performance, but they are not sufficient for evaluating an entire product with multiple characteristics. [Chen, K.S., Huang, M.L., Li, R.K., 2001. Process capability analysis for an entire product. International Journal of Production Research 39(17), 4077-4087] proposed the process capability analysis chart (PCAC), applied indices Cpu, Cpl and Cpa to evaluate the integrated process capability for a multi-process product. However, as noted by [Pearn, W.L., Chen, K.S., 1997. Multi-process performance analysis: a case study. Quality Engineering 10(1), 1-8], when we take into account the asymmetric tolerance, Cpn reflects the process capability more accurately and is superior to index Cpa. In this paper, we select Cpn to replace Cpa, and reconstruct a process capability monitoring chart (PCMC) for evaluating process potentials and performance for an entire product, which consists of smaller-the-better (with Cpu), larger-the-better (with Cpl), nominal-the-best (with Cpn) specifications, respectively. Meanwhile, an integrated product capability index is proposed, and the relationship between the index and the process yield of an entire product is described. A PCMC, which reasonably and accurately indicates the status of all process capabilities for the silicon-filler product, is designed for practical applications.