Multiple streams process capability analysis chart

Process capability plots with single stream process have earlier been discussed by Deleryd and Vännman (1999); however multiple streams process often exists in practice. In the present paper, we introduce a new control chart, called the multiple streams process capability analysis(MSPCA) chart, using the multiple streamsyield index proposed by Wang et al. (2008). The MSPCA chart displays all the stream capability index values on one chart, and indicates the stream yield based on the Spkcontours. Using the chart, engineers can effectively monitor and control the performance of all streams process simultaneously. In addition, the MSPCA chart also provides a clear direction on the streams that should be targeted for quality/reliability improvement. We demonstrate the use of MSPCA chart by presenting a case study of an IC assembly process auto-molding system.