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Article
Publication date: 1 December 1993

S.K. Goyal, A. Gunasekaran, T. Martikainen and P. Yli‐Olli

Presents a mathematical model for determining Economic ProductionQuantity (EPQ) in a multistage flow‐shop production system for the casewhere the demand for items per unit…

Abstract

Presents a mathematical model for determining Economic Production Quantity (EPQ) in a multistage flow‐shop production system for the case where the demand for items per unit time is deterministic and the planning horizon is finite. Solves an example problem to illustrate the model.

Details

International Journal of Operations & Production Management, vol. 13 no. 12
Type: Research Article
ISSN: 0144-3577

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Article
Publication date: 8 November 2011

Matloub Hussain and Paul R. Drake

The purpose of this paper is to understand the effect of batching on bullwhip effect in a model of multi‐echelon supply chain with information sharing.

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2817

Abstract

Purpose

The purpose of this paper is to understand the effect of batching on bullwhip effect in a model of multi‐echelon supply chain with information sharing.

Design/methodology/approach

The model uses the system dynamics and control theoretic concepts of variables, flows and feedback processes and is implemented using iThink® software.

Findings

It has been seen that the relationship between batch size and demand amplification is non‐monotonic. Large batch sizes, that when combined in integer multiples can produce order rates that are close to the actual demand, produce little demand amplification, i.e. it is the size of the remainder of the quotient that is the determinant. It is further noted that the value of information sharing is greatest for smaller batch sizes, for which there is a much greater improvement in the amplification ratio.

Research limitations/implications

Batching is associated with the inventory holding and backlog cost. Therefore, future work should investigate the cost implications of order batching in multi‐echelon supply chains.

Practical implications

This is a contribution to the continuing research into the bullwhip effect, giving supply chain operations managers and designers a practical way into controlling the bullwhip produced by batching across multi‐echelon supply chains.

Originality/value

Previous similar studies have used control theoretic techniques and it has been pointed out that control theorists are unable to solve the lot sizing problem. Therefore, system dynamic simulation has been applied to investigate the impact of various batch sizes on bullwhip effect.

Details

International Journal of Physical Distribution & Logistics Management, vol. 41 no. 10
Type: Research Article
ISSN: 0960-0035

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Article
Publication date: 6 September 2011

Matloub Hussain and Paul R. Drake

The purpose of this paper is to analyze the effect of batching on bullwhip effect in a model of multi‐echelon supply chain with information sharing.

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2315

Abstract

Purpose

The purpose of this paper is to analyze the effect of batching on bullwhip effect in a model of multi‐echelon supply chain with information sharing.

Design/methodology/approach

The model uses the system dynamics and control theoretic concepts of variables, flows, and feedback processes and is implemented using iThink® software.

Findings

It has been seen that the relationship between batch size and demand amplification is non‐monotonic. Large batch sizes, when combined in integer multiples, can produce order rates that are close to the actual demand and produce little demand amplification, i.e. it is the size of the remainder of the quotient that is the determinant. It is further noted that the value of information sharing is greatest for smaller batch sizes, for which there is a much greater improvement in the amplification ratio.

Research limitations/implications

Batching is associated with the inventory holding and backlog cost. Therefore, future work should investigate the cost implications of order batching in multi‐echelon supply chains.

Practical implications

This is a contribution to the continuing research into the bullwhip effect, giving supply chain operations managers and designers a practical way into controlling the bullwhip produced by batching across multi‐echelon supply chains. Economies of scale processes usually favor large batch sizes. Reducing batch size in order to reduce the demand amplification is not a good solution.

Originality/value

Previous similar studies have used control theoretic techniques and it has been pointed out that control theorists are unable to solve the lot sizing problem. Therefore, system dynamic simulation is then applied to investigate the impact of various batch sizes on bullwhip effect.

Details

International Journal of Physical Distribution & Logistics Management, vol. 41 no. 8
Type: Research Article
ISSN: 0960-0035

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Article
Publication date: 1 February 1986

C. Carl Pegels

A batch size model developed for the therapeutic product problem has been instrumental in assisting the staff of a large general hospital to resolve problems associated…

Abstract

A batch size model developed for the therapeutic product problem has been instrumental in assisting the staff of a large general hospital to resolve problems associated with the transactional process of the preparation of intravenous medications for administration. The model is a variation of a basic profit maximisation model and is characterised by variable batch preparation cost, a variable planning period, fixed per unit base cost, and zero shortage costs since preparation of a new batch can take place without delay. The variable planning period is transformed into a fixed planning horizon which is at least several multiples of the planning period and is fixed. Development of the model is presented and illustrated with a hypothetical situation, followed by a real case — the determination of the optimal batch size for the intravenous drug, Cefazolin.

Details

International Journal of Operations & Production Management, vol. 6 no. 2
Type: Research Article
ISSN: 0144-3577

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Article
Publication date: 1 March 2003

Fahad Al‐Mubarak, Basheer M. Khumawala and Cem Canel

This paper is aimed at comparing cellular manufacturing with focused cellular manufacturing. We define focused cellular manufacturing as a layout scheme that groups…

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1939

Abstract

This paper is aimed at comparing cellular manufacturing with focused cellular manufacturing. We define focused cellular manufacturing as a layout scheme that groups components by end‐items and forms cells of machines to fabricate and assemble end‐items. It is not classified as a cellular manufacturing layout since it does not attempt to take advantage of process similarities. It also is not classified as a flow shop since there are no machines dedicated to individual operations and the machines are not arranged in a series. In addition, this research includes batching and assemble times in its criteria which few researchers in this area have done. The results indicate that the focused cellular manufacturing scheme has a batching advantage. This advantage out‐weighed the set‐up time reduction advantage of the cellular manufacturing scheme for average end‐item completion times and average work‐in‐process inventory levels. The cellular manufacturing scheme overcame the batching advantage only when there were small batch sizes or large set‐up time magnitudes.

Details

International Journal of Operations & Production Management, vol. 23 no. 3
Type: Research Article
ISSN: 0144-3577

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Article
Publication date: 3 June 2021

Maedeh Bank, Mohammad Mahdavi Mazdeh, Mahdi Heydari and Ebrahim Teimoury

The aim of this paper is to present a method for finding the optimum balance between sequence-dependent setup costs, holding costs, delivery costs and delay penalties in…

Abstract

Purpose

The aim of this paper is to present a method for finding the optimum balance between sequence-dependent setup costs, holding costs, delivery costs and delay penalties in an integrated production–distribution system with lot sizing decisions.

Design/methodology/approach

Two mixed integer linear programming models and an optimality property are proposed for the problem. Since the problem is NP-hard, a genetic algorithm reinforced with a heuristic is developed for solving the model in large-scale settings. The algorithm parameters are tuned using the Taguchi method.

Findings

The results obtained on randomly generated instances reveal a performance advantage for the proposed algorithm; it is shown that lot sizing can reduce the average cost of the supply chain up to 11.8%. Furthermore, the effects of different parameters and factors of the proposed model on supply chain costs are examined through a sensitivity analysis.

Originality/value

Although integrated production and distribution scheduling in make-to-order industries has received a great deal of attention from researchers, most researchers in this area have treated each order as a job processed in an uninterrupted time interval, and no temporary holding costs are assumed. Even among the few studies where temporary holding costs are taken into consideration, none has examined the effect of splitting an order at the production stage (lot sizing) and the possibility of reducing costs through splitting. The present study is the first to take holding costs into consideration while incorporating lot sizing decisions in the operational production and distribution problem.

Details

Kybernetes, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0368-492X

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Article
Publication date: 1 February 1996

Peter Burcher, Simon Dupernex and Geoffrey Relph

Places research undertaken into a periodic order cycle inventory management system for repetitive batch manufacturers into the context of lean production and world class…

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2963

Abstract

Places research undertaken into a periodic order cycle inventory management system for repetitive batch manufacturers into the context of lean production and world class manufacturing. Describes the attributes of the current marketplace, and how approaches used by successful users of the world‐class manufacturing and lean production techniques can be applied to a repetitive batch environment. Proposes a methodology to help traditional repetitive batch manufacturers in a route to continual improvement by: highlighting those areas where change would bring the greatest benefits; modelling the effect of proposed changes; quantifying the benefits that could be gained through implementing the proposed changes; and simplifying the effort required to perform the modelling process. Concentrates on increasing flexibility through managed inventory reduction by rationally decreasing batch sizes, taking account of sequence dependent set‐ups and the identification and elimination of bottlenecks.

Details

International Journal of Operations & Production Management, vol. 16 no. 2
Type: Research Article
ISSN: 0144-3577

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Article
Publication date: 15 February 2008

Amy H.I. Lee and He‐Yau Kang

This paper seeks to construct a model for inventory management for multiple periods. The model considers not only the usual parameters, but also price quantity discount…

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1272

Abstract

Purpose

This paper seeks to construct a model for inventory management for multiple periods. The model considers not only the usual parameters, but also price quantity discount, storage and batch size constraints.

Design/methodology/approach

Mixed 0‐1 integer programming is applied to solve the multi‐period inventory problem and to determine an appropriate inventory level for each period. The total cost of materials in the system is minimized and the optimal purchase amount in each period is determined.

Findings

The proposed model is applied in colour filter inventory management in thin film transistor‐liquid crystal display (TFT‐LCD) manufacturing because colour filter replenishment has the characteristics of price quantity discount, large product size, batchsized purchase and forbidden shortage in the plant. Sensitivity analysis of major parameters of the model is also performed to depict the effects of these parameters on the solutions.

Practical implications

The proposed model can be tailored and applied to other inventory management problems.

Originality/value

Although many mathematical models are available for inventory management, this study considers some special characteristics that might be present in real practice. TFT‐LCD manufacturing is one of the most prosperous industries in Taiwan, and colour‐filter inventory management is essential for TFT‐LCD manufacturers for achieving competitive edge. The proposed model in this study can be applied to fulfil the goal.

Details

Kybernetes, vol. 37 no. 1
Type: Research Article
ISSN: 0368-492X

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Article
Publication date: 1 April 1976

Thomas J. Love and Peter Gilmour

In general small companies have not taken advantage of the potential of integrated physical distribution management to reduce costs, improve customer service and increase…

Abstract

In general small companies have not taken advantage of the potential of integrated physical distribution management to reduce costs, improve customer service and increase profits. This is because the most publicised corporate distribution studies have used, as the tool for analysis, large computer simulation models. This paper reviews the distribution operation of Castrol (Australia) Pty. Ltd. a relatively small company involved in the blending and distribution of oil products. All analyses discussed were carried out on a pocket calculator. The procedures described provide a framework for other small companies to follow when evaluating their distribution operations.

Details

International Journal of Physical Distribution, vol. 6 no. 6
Type: Research Article
ISSN: 0020-7527

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Article
Publication date: 8 June 2015

Lluís Cuatrecasas-Arbós, Jordi Fortuny-Santos, Patxi Ruiz-de-Arbulo-López and Carla Vintró-Sanchez

Since lean manufacturing considers that “Inventory is evil”, the purpose of this paper is to find and quantify the relations between work-in-process inventory (WIP)…

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1977

Abstract

Purpose

Since lean manufacturing considers that “Inventory is evil”, the purpose of this paper is to find and quantify the relations between work-in-process inventory (WIP), manufacturing lead time (LT) and the operational variables they depend upon. Such relations provide guidelines and performance indicators in process management.

Design/methodology/approach

The authors develop equations to analyse how, in discrete deterministic serial batch processes, WIP and LT depend on parameters like performance time (of each workstation) and batch size. The authors extend those relations to processes with different lots and the authors create a multiple-lot box score.

Findings

In this paper, the relations among WIP, LT and the parameters they depend on are derived. Such relations show that when WIP increases, LT increases too, and vice versa, and the parameters they depend on. Finally, these relations provide a framework for WIP reduction and manufacturing LT reduction and agree with the empirical principles of lean manufacturing.

Research limitations/implications

Quantitative results are only exact for discrete deterministic batch processes without any delays. Expected results might not be achieved in real manufacturing environments. However, qualitative results show the underlying relations amongst variables. Different expressions might be derived for other situations.

Practical implications

Understanding the relations between manufacturing variables allows operations managers better design, implement and control manufacturing processes. The box score, implemented on a spreadsheet, allows testing the effect of changes in different operational parameters on the manufacturing LT, total machine wait time and total lot queue time.

Originality/value

The paper presents a discussion about process performance based on the mutual influence between WIP and LT and other variables. The relation is quantified for the discrete deterministic case, complementing the models that exist in the literature. The box score allows mapping more complex processes.

Details

Industrial Management & Data Systems, vol. 115 no. 5
Type: Research Article
ISSN: 0263-5577

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