Minimisation of inspection and rework cost in a BLU factory considering imperfect inspection

Abstract

We address an optimisation problem for minimising the cost of both the inspection and the rework incurred throughout an interconnected inspection–rework system. In order to formulate the relevant cost objective function, assuming imperfect inspection, we make a time-based flow analysis between nodes (or shops), and derive the limiting sizes of flows between nodes and the limiting fraction defective by solving a set of nonlinear balance equations. We provide an enumeration method for determining the optimal frequency of inspection cycles at the end of assembly lines which minimises the relevant cost of inspection and rework.

Keywords:

• imperfect inspection
• inspection cost
• rework cost

Acknowledgements

The authors would like to thank the referee for his helpful comments, in particular his comment on the idea of Corollary 4 in this paper and the possible application of a Markov chain-based optimization model to our problem. The present research was conducted by the research fund of Dankook University in 2012.