A demerits control chart for autocorrelated data

摘要

A new moving centerline demerits (MCD) control chart is developed for monitoring process quality where there are multiple nonconformity severity levels and measurements tend to be autocorrelated. This extends the traditional demerits control chart, which assumes samples are independent. The MCD control chart is applied to actual data from injection molding production lines. Results show that the MCD chart performs well in signaling an out-of-control conditions. (13 refs.)