Jaehn, Alfred H. (1989, ASQC) Consolidated Papers, Inc., Wisconsin Rapids, WI
The zone control chart method for variables data was first introduced by the author at the 1987 ASQC Annual Congress. Since then, interest in the application of this new control charting procedure has grown rapidly.
The zone control chart is a quality control tool that can be universally applied to any process where the data are normally distributed. Major application has been in process control, quality measurement, and analyses of quality performance. Its unique design has been found particularly advantageous in eliminating the need for constructing separate control charts for each individual process and measurement. Operator jobs have been made easier. Sound statistical tests for identifying shifts in process level automatically incorporated into the procedure eliminated the need for remembering the various control chart rules.
This paper reviews the basic zone control chart method and presents the status of current usage. Experience with the application of these charts in several industries is cited.
To date, applications of zone control charts have been specifically in the control of the process average. Since a process can also shift in variation, the further use of zone control charts for the control of ranges is also examined.
Chemical and process industries,Control charts