scholarly journals AN ARITHMETIC-GEOMETRIC MEAN INEQUALITY APPROACH FOR DETERMINING THE OPTIMAL PRODUCTION LOT SIZE WITH BACKLOGGING AND IMPERFECT REWORK PROCESS

2017 ◽  
Vol 7 (1) ◽  
pp. 224-235
Author(s):  
Chun-Tao Chang ◽  
◽  
Liang-Yuh Ouyang ◽  
Keyword(s):  
Geometric Mean ◽  
Lot Size ◽  
Optimal Production ◽  
Production Lot Size ◽  
Rework Process

Optimal production lot sizing for an imperfect manufacturing system with machine breakdown and emergency maintenance policy

Kybernetes ◽  
2019 ◽  
Vol 49 (5) ◽  
pp. 1533-1560
Author(s):  
Xinfeng Lai ◽  
Zhixiang Chen ◽  
Bhaba R. Sarker
Keyword(s):  
Manufacturing System ◽  
Lot Sizing ◽  
Lot Size ◽  
Maintenance Policy ◽  
Managerial Implication ◽  
Optimal Production ◽  
Expected Cost ◽  
Content Type ◽  
Machine Breakdown ◽  
Production Lot Size

Purpose The purpose of this paper is to study a production lot sizing problem with consideration of imperfect manufacturing and emergency maintenance policy, providing managerial implication for practitioners. Design/methodology/approach In this study, the authors introduce two models, where in Model I, shortages are not allowed and repair times are negligible. In Model II, shortages are allowed and are partially backlogged, and repair times are assumed to be exponentially distributed, algorithm is developed to solve the models, numerical examples were demonstrated the applications. Findings Results show that in the Model I, demand rate is the most significant parameter affecting the average expected cost, whereas the time needed to breakdown after machine shift is the most significant factor affecting the production lot size. Therefore, reduction in the time needed to breakdown after machine shift would be helpful for determining an appropriate production lot size in Model I. In Model II, repair time parameter is the most significant factor affecting the average expected cost. Reducing the value of machine shift parameter would be helpful for determining an adequate production lot size and reducing decision risk. Practical implications This paper can provide important reference value for practitioners with managerial implication of how to effectively maintain equipment, i.e. how to make product lot size considering the influence of the maintenance policy. Originality/value From the aspect of academia, this paper provides a solution to the optimal production lot sizing decision for an imperfect manufacturing system with consideration of machine breakdown and emergency maintenance, which is a supplement to imperfect EMQ model.

Optimal production lot size under backup agreement allowing substitute products

2020 ◽  
Vol 54 (5) ◽  
pp. 1309-1326
Author(s):  
Wen-Chin Tsai ◽  
Chih-Hsiung Wang
Keyword(s):  
Third Party ◽  
Manufacturing Cost ◽  
Profit Function ◽  
Market Demand ◽  
Fashion Industry ◽  
Lot Size ◽  
Optimal Production ◽  
Substitute Products ◽  
The Impact ◽  
Production Lot Size

In the fashion industry, a flexible backup agreement contract allows the retailer to order a partial amount from the backup quantity to allay the risk of uncertain market demand. However, under such a contract, the manufacturer faces the risk of bearing a huge leftover if the quantity realized by the retailer in backup is small. Accordingly, the present study considers a modified backup agreement in which the manufacturer is permitted to urgently purchase substitute products to satisfy the backup order from a third-party supplier, but at a unit purchase cost greater than the original unit manufacturing cost. The corresponding expected total profit function for the manufacturer is established and shown to be concave. The profit function is used to explore various useful properties for determining the optimal production lot size. In addition, an illustrated numerical example is provided to analyze the impact of the backup contract terms on the optimal production lot size and manufacturer’s profit.

Note on “Effects of Random Defective Rate and Imperfect Rework Process on Economic Production Quantity Model”

2005 ◽  
Vol 128 (1) ◽  
pp. 375-377 ◽  
Author(s):  
Yuan-Shyi Peter Chiu ◽  
Singa Wang Chiu
Keyword(s):  
Algebraic Approach ◽  
Lot Size ◽  
Inventory Cost ◽  
Economic Production Quantity ◽  
Economic Production ◽  
Production Inventory ◽  
Epq Model ◽  
Production Quantity ◽  
Production Lot Size ◽  
Rework Process

Conventional approaches for deriving optimal production lot size are by using the differential calculus on the production-inventory cost function with the need to prove optimality first. Recent articles proposed the algebraic approach to the solution of classic economic order quantity and economic production quantity (EPQ) model without reference to the use of derivatives. This note extends it to an EPQ model taking the random defective rate and imperfect rework process into consideration. We demonstrate that the optimal lot size can be solved algebraically and the expected inventory cost can be derived immediately as well.

scholarly journals A finite horizon production model with variable production rates and constant demand rate

2002 ◽  
Vol 6 (2) ◽  
pp. 71-78 ◽  
Author(s):  
Zvi Goldstein
Keyword(s):  
Production Rate ◽  
Finite Horizon ◽  
Production Model ◽  
Maximum Speed ◽  
Lot Size ◽  
Production Problem ◽  
Demand Rate ◽  
The Cost ◽  
Production Lot Size ◽  
Variable Production

In this paper we present a finite horizon single product single machine production problem. Demand rate and all the cost patterns do not change over time. However, end of horizon effects may require production rate adjustments at the beginning of each cycle. It is found that no such adjustments are required. The machine should be operated either at minimum speed (i.e. production rate = demand rate; shortage is not allowed), avoiding the buildup of any inventory, or at maximum speed, building up maximum inventories that are controlled by the optimal production lot size.

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