Title: Optimising Shewhart charts in parallel production lines

Authors: Ronald D. Fricker, Jr.

Addresses: Operations Research Department, Naval Postgraduate School, Monterey, California 93943, USA

Abstract: I describe a methodology for optimising n Shewhart x-charts operating on parallel production lines in a factory. The goal is to maximise the factory-wide probability of detecting an out-of-control condition subject to a constraint on the expected number of false signals. I use non-linear programming to appropriately set the x-charts| control limits incorporating information about the probability of each production line going out-of-control. Using this approach, factories can set their quality control systems to optimally detect out-of-control conditions. Given some distributional assumptions, I also present a one-dimensional optimisation methodology that allows for the efficient optimisation of very large factories.

Keywords: industrial quality control; statistical process control; SPC; control charts; x-bar charts; quality engineering; quality technology; optimisation; Shewhart charts; parallel production lines.

DOI: 10.1504/IJQET.2009.031126

International Journal of Quality Engineering and Technology, 2009 Vol.1 No.2, pp.125 - 135

Published online: 21 Jan 2010 *

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