Study of imperfect production processes with shortages

(2005) Study of imperfect production processes with shortages. Masters thesis, King Fahd University of Petroleum and Minerals.


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We consider the Economic Production Quantity Model where the process goes out of control after a point within the production cycle. Shortages are allowed. The total cost function is developed which consists of set up cost, shortage cost, holding cost and cost of rework. The problem is to find the production time which minimizes the total cost. The study generalizes the work of Chung and Hou (2003), Hou (2005), Rahim and Hajailan (2006). Chung and Hou [2003] considered the case where the defective rate is a constant percentage of the production. In this work we extended their work in three directions. In the first we consider the case where the percent of defectives is proportion to the time the process is out of control to the total production cycle which is Rahim and Hajailan (2006). In the Model II when the process goes out-of-control the percentage of defectives rate increases using an exponential function. However, Model III considers the case where the process mean shifts after a random duration. The defective rate is determined by the percentage of the production outside the specification limits. In the first model we consider several distribution functions for the time to failure, namely the exponential distribution, the Weibull distribution, the Gamma distribution and the Normal distribution. In the Model II and Model III we consider only the case where the time to failure is exponentially distributed. We show that the objective function is generally nonconvex for all the cases studied regardless of the probability distribution of the time to failure. The objective function is convex for particular values of problem parameters. Sensitivity analysis is performed for the case of exponential time to failure for Rahim and Hajailan (2006) Model I, Model II, and Model III. In addition, warranty repair cost also has been incorporated for all models. The thesis is concluded by suggesting a number of recommendations for future research.

Item Type: Thesis (Masters)
Subjects: Engineering
Department: College of Computing and Mathematics > lndustrial and Systems Engineering
Committee Advisor: Selim, Shokri Zaki
Committee Members: Al-Turki, Umar Mustafa and Rahim, M. A.
Depositing User: Mr. Admin Admin
Date Deposited: 22 Jun 2008 14:07
Last Modified: 01 Nov 2019 14:02