OPTIMUM ALLOCATION OF INSPECTION EFFORT IN MULTISTAGE MANUFACTURING PROCESSES

摘要

The allocation of inspection effort (AIE) in multi-stage manufacturing system has been studied extensively over the last fifty years. The objective of this paper is to review the existing approaches, propose a classification of the available models in terms of the type of manufacturing system that they refer to and the applied solution methods and examine the effectiveness of the inspection strategies by developing appropriate generalised algorithm and software tool. The review revealed firstly that inspection allocation problem has been studied comprehensively by using variety of analytical and Monte-Carlo simulation methods rather than combination of both simulation techniques in a simulation-optimisation framework. Secondly large proportion of the papers focuses on several work stations representing part of a manufacturing line without attempting to solve the global optimisation problem which lead to solutions based on complete enumeration that are known to be computationally ineffective when the number of workstations increase. The developed simulation program demonstrated that methods determining the position of inspection by using complete enumeration method (EM) are of limited use in the majority of manufacturing situations when the number of workstations exceeds eighteen. This led to the development of a heuristic algorithm the performance of which was compared with the complete enumeration algorithm. It was found that heuristic method can derive an acceptable solution significantly faster. At present authors continue to develop heuristic algorithms for the AIE problem and methaheuristics using biologically inspired techniques.