An improved attribute control chart for monitoring non-conforming proportion in high quality processes?

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2013 vol. 21 p. 407 - 407

p align="left"> Processes with very low rate of nonconformities are frequently observed in practice. These processes are known as high quality processes. Traditionally, the study of the rate of nonconformities was carried out using the conventional 3-sigma p control chart (Shewhart), constructed by the normal approximation. But this p chart suffers a serious inaccuracy in the modeling process and in control limits specification when the true rate of nonconforming items is small. This paper shows that, with simple adjustments to the control limits of the