Abstract
The CCC (Cumulative Count of Conforming) chart of which quality characteristic is the cumulative count of conforming items inspected before observing a nonconforming one has been discussed by several researchers, Bourke, Kaminsky et al., Nelson, Glushkobsky, and Xie et al. Moreover, Xie et al. have extended the CCC chart to the CCC-γ chart of which quality characteristic is the cumulative count of conforming items inspected before observing γ (≥2) nonconforming ones to detect more sensitively changes in the fraction defective p for high-yield processes. Recently, Wu et al. have presented a Synthetic chart that is an integration of the Shewhart-type charts, such as x^^- chart and p chart, and the CCC chart to have a higher power for detecting moderate process shifts in quality characteristics on Shewhart-type charts. Kusukawa and Ohta have presented the CS (Confirmation Sample)ccc-γ chart for detecting more sensitively small or moderate changes in p for both upward and downward shifts in high-yield processes. As a superior chart for high-yield processes, we present a new Synthetic chart for high-yield processes that is an integration of the CSccc-γ chart and the CCC-γ chart. In use of the proposed Synthetic chart, the quality characteristic is initially judged as either in-control or out-of-control, using the confirmation control limits of the CSccc-γ chart. If the process was not judged as in-control by the CSccc-γ chart, the process is successively judged by using the CCC-γ chart for conforming the judgement of the CSccc-γ chart. It is demonstrated through computer simulation that the proposed Synthetic chart is more sensitive in detecting small or moderate changes in p for both of upward and downward shifts in high-yield processes than the CSccc-γ chart by comparing the ANOS (Average Number of Observations to Signal) of the proposed chart and those of the CSccc-γ chart.
