The influence of measurement error on calculation of process capability indices and proportion of conformance

The influence of measurement error on the calculation of Process Capability Indices (PCIs) and proportion of conformance is proposed. General calculation formulas are given to calculate the PCIs (Cp, Cpk, Cpm, Cpmk) and proportion of conformance when measurement error is present. The relationship between PCIs and proportion of conformance is established based on measurement error. The influence of measurement on PCIs and the proportion of conformance is analysed by simulation.