EWMA Control Charts for Monitoring High Yield Processes

Abstract

The main objective of this article is to scrutinize the efficiency and verify the performance superiority of the one-sided EWMA control chart on high-yield processes. The proposed control chart is designed to detect both upward and downward shifts of the fraction of non conforming products and is developed based on non transformed geometric counts. Its algorithmic function is theoretically established and numerous performance measures are extracted using analytical methods based on the Markov modeling of the chart. Comparisons with traditional high yield control charts are conducted. Optimality tables and nomograms are included to help graphical determination of the optimal chart parameters.

Keywords:

• Average run length
• EWMA
• Geometric counts
• High-yield processes
• Markov chain
• Statistical process control

Mathematics Subject Classification:

• 60G35
• 93E10