G-EWMAG Control Chart for High-Quality Processes

• Activity Number: 181
• Type: Contributed
• Date/Time: Monday, August 2, 2010 : 10:30 AM to 12:20 PM
• Sponsor: Section on Quality and Productivity
• Author(s): Chang Wook Kang*+ and Jae-Won Baik and Hae-Woon Kang and Min Song
• Companies: Hanyang University and Hanyang University and Hanyang University and Hanyang University
• Keywords: Average run length ; G control chart ; G-EWMAG control chart ; alpha ratio

Abstract

G control chart is used to monitor and detect any change in high-quality processes. This control chart is based on plotting of G statistic which is the number of conforming units that comes out between two consecutive non-conforming units. However, there are some drawbacks in G control chart applying to high-quality processes, as it has low performance in detecting small shifts. The EWMA control chart is widely used in order for detecting small shift. In this paper, G-EWMAG control chart is proposed to detect small shifts in the high-quality processes. The run length properties of G-EWMAG control chart are studied and compared with G control chart at different fraction non-conforming units and process shifts. G-EWMAG control chart with alpha ratio smaller than 0.3 is efficient for small shift. Finally, the implementation of G-EWMA is illustrated in one real-world example.