Original scientific paper
Incorporating machine reliability issue and backlogging into the EMQ model - Part I: Random breakdown occurring in backorder filling time
Yuan-Shyi Peter Chiu
; Department of Industrial Engineering, Chaoyang University of Technology, Jifong East Road, Wufong, Taichung 413, TAIWAN
Yu-Lung Lien
; Department of Industrial Engineering, Chaoyang University of Technology, Jifong East Road, Wufong, Taichung 413, TAIWAN
Chih-An Katherine Lin
; Department of Industrial Engineering, Chaoyang University of Technology, Jifong East Road, Wufong, Taichung 413, TAIWAN
Abstract
This study is concerned with determination of the optimal replenishment policy for economic manufacturing quantity (EMQ) model with backlogging and machine reliability issue. Classic EMQ model does not consider nonconforming items generated during a production cycle, nor does it deal with the machine breakdown situation. It is noted that in manufacturing system when back-ordering is permitted, a random machine failure can take place in either backorder filling time or in on-hand inventory piling period. The first phase of this study examines the
aforementioned practical issues by incorporating rework process of defective items, scrap and random machine failure taking place specifically in backorder satisfying time into the EMQ model. The objective is to determine the optimal replenishment lot-size that minimizes the overall production-inventory costs. Mathematical modelling and analysis is used and the renewal reward theorem is employed to cope with the variable cycle length. Theorem on conditional convexity of total cost function is proposed and proved. The optimal lot size for such a real-life imperfect manufacturing system is derived. A numerical example is given to demonstrate its practical usage.
Keywords
production; machine breakdown; EMQ model; rework; lot sizing; scrap; random defective rate
Hrčak ID:
185756
URI
Publication date:
4.5.2011.
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