Διαγράμματα ελέγχου με μεταβλητό ρυθμό δειγματοληψίας

Abstract

What is of interest, in productive processes, is monitoring the behavior of a quality attribute of the product that is produced. This monitoring procedure is done using optimal control charts. It is common when using control charts, to take samples with fixed sample sizes in fixed sampling intervals. In the present work, we present some studies related to the design of control charts in which the sample size or the sampling interval may vary. Moreover, we will compare the detection speed of these charts against the classical control charts. We will work on X , np , CUSUM, EWMA and Hotelling’s 2 T control charts. In any case, all the comparisons are done using known statistical indices, such as, the average time to signal (ATS) and the average number of samples to signal (ANSS).