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Process capability plots—a quality improvement tool

1999; Wiley; Volume: 15; Issue: 3 Linguagem: Inglês

10.1002/(sici)1099-1638(199905/06)15

1099-1638

Mats Deleryd, Kerstin Vännman,

Advanced Statistical Methods and Models

Quality and Reliability Engineering InternationalVolume 15, Issue 3 p. 213-227 Research Article Process capability plots—a quality improvement tool Mats Deleryd, Mats Deleryd Division of Quality Technology and Statistics, Luleå University of Technology, SE-97187 Luleå, SwedenSearch for more papers by this authorKerstin Vännman, Corresponding Author Kerstin Vännman Division of Quality Technology and Statistics, Luleå University of Technology, SE-97187 Luleå, SwedenDivision of Quality Technology and Statistics, Luleå University of Technology, SE-97187 Luleå, Sweden===Search for more papers by this author Mats Deleryd, Mats Deleryd Division of Quality Technology and Statistics, Luleå University of Technology, SE-97187 Luleå, SwedenSearch for more papers by this authorKerstin Vännman, Corresponding Author Kerstin Vännman Division of Quality Technology and Statistics, Luleå University of Technology, SE-97187 Luleå, SwedenDivision of Quality Technology and Statistics, Luleå University of Technology, SE-97187 Luleå, Sweden===Search for more papers by this author First published: 17 June 1999 https://doi.org/10.1002/(SICI)1099-1638(199905/06)15:3 3.0.CO;2-OCitations: 55AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract We introduce the concept of process capability plots, which are powerful tools to monitor and improve the capability of industrial processes. An advantage of using a process capability plot, compared with using a traditional process capability index alone, when deciding whether a process can be considered capable or not, is that we will instantly get information about the location and spread of the studied characteristic. When the process is non-capable, the plots are helpful when trying to understand if it is the variability, the deviation from target or both that need to be reduced to improve the capability. In this way the proposed graphical methods give a clear direction of quality improvement. We evaluate two different process capability plots, the (δ*, γ*)-plot and the confidence rectangle plot, from a theoretical as well as a practical point of view. When studying them from a theoretical point of view, among other things, a simulation study is conducted to investigate the ability of each of the two methods to identify that a process is capable when it actually is. The comparison from a practical point of view is made by discussing the advantages and disadvantages of the two methods in different practical situations. Based on the above-mentioned comparisons, the recommendation is that the practitioner should use the (δ*, γ*)-plot. Copyright © 1999 John Wiley & Sons, Ltd. Citing Literature Volume15, Issue3May/June 1999Pages 213-227 RelatedInformation