Process capability in industry: Setting preliminary statistical specification limits

摘要

In industrial processes, capability indices like the C_(pk) are frequently used. This index requires that specification limits have been set. The current paper focuses on the issue to set preliminary specification limits based on the statistical performance of the process alone. This preliminary interval should correspond to a C_(pk) value that is considered to be sufficiently high, with a pre-specified confidence level. The paper presents a theoretical framework to set these limits.