Adapting EWMA Control Charts for Batch-Correlated Data

Batch production is common in the chemical and process industries. This article demonstrates how EWMA charts should be modified to account for substantial batch-to-batch variation. A batch-correlation model is considered, and methods of estimation and hypothesis testing for the batch-correlation coefficient are developed. This discussion is most appealing for production processes in which items are processed in batches but are related within batch.

[1]  Roland Caulcutt,et al.  Control chart design - A review of standard practice , 1992 .

[2]  S. W. Roberts,et al.  Control Chart Tests Based on Geometric Moving Averages , 2000, Technometrics.

[3]  Carl E. Noble.  VARIATIONS IN CONVENTIONAL CONTROL CHARTS , 1998 .

[4]  S. Crowder.  A simple method for studying run-length distribution of exponentially weighted moving average charts , 1987 .

[5]  Amit Mitra,et al.  Statistical Quality Control , 2002, Technometrics.

[6]  John B. Neuhardt,et al.  Effects of Correlated Sub-Samples in Statistical Process Control , 1987 .

[7]  Donald J. Wheeler,et al.  Understanding Statistical Process Control , 1986 .

[8]  W. H. Deitenbeck.  Introduction to statistical process control. , 1995, Healthcare facilities management series.

[9]  Gerald J. Hahn,et al.  Adapting control charts to meet practical needs: a chemical processing application , 1987 .

[10]  Stephen V. Crowder,et al.  An EWMA for Monitoring a Process Standard Deviation , 1992 .

[11]  William H. Woodall,et al.  Statistical process control with several components of common cause variability , 1995 .

[12]  P. Young,et al.  Time series analysis, forecasting and control , 1972, IEEE Transactions on Automatic Control.

[13]  D. Coleman.  Statistical Process Control—Theory and Practice , 1993 .

[14]  S. Crowder.  Average Run Lengths of Exponentially Weighted Moving Average Control Charts , 1987 .

[15]  G. Barrie Wetherill,et al.  Statistical Process Control , 1991 .

[16]  James M. Lucas,et al.  Exponentially weighted moving average control schemes: Properties and enhancements , 1990 .