Procedure for Process Control with Inspection Errors

• Activity Number: 420
• Type: Contributed
• Date/Time: Tuesday, July 31, 2012 : 2:00 PM to 3:50 PM
• Sponsor: Quality and Productivity Section
• Author(s): Michelle Smith*+ and William S. Griffith
• Companies: Eastern Kentucky University and University of Kentucky
• Keywords: Acceptance Sampling ; Attribute ; Misclassification ; Process Control ; Runs

Abstract

Several papers have considered the procedure of online process control when the possibility of misclassification of items exists. In this paper, we consider online process control in which every hth item is inspected. The item is subjected to repeated independent classifications and will ultimately judged to be a conforming item if there are k consecutive judgments that it is conforming prior to a f consecutive judgments that it is nonconforming. When the item is ultimately judged to be nonconforming, the process is stopped and a search for a cause is conducted. If no cause is found, the process is put back online. When the item is judged as conforming, the process continues. There is a possibility of a misclassification of a conforming item as nonconforming and nonconforming item as conforming. We derived the probabilities of several quantities of interest for this model.