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Article
Publication date: 8 March 2013

Oladipupo A. Olaitan and John Geraghty

The aims of this paper is to investigate simulation‐based optimisation and stochastic dominance testing while employing kanban‐like production control strategies (PCS) operating…

Abstract

Purpose

The aims of this paper is to investigate simulation‐based optimisation and stochastic dominance testing while employing kanban‐like production control strategies (PCS) operating dedicated and, where applicable, shared kanban card allocation policies in a multi‐product system with negligible set‐up times and with consideration for robustness to uncertainty.

Design/methodology/approach

Discrete event simulation and a genetic algorithm were utilised to optimise the control parameters for dedicated kanban control strategy (KCS), CONWIP and base stock control strategy (BSCS), extended kanban control strategy (EKCS) and generalised kanban control strategy (GKCS) as well as the shared versions of EKCS and GKCS. All‐pairwise comparisons and a ranking and selection technique were employed to compare the performances of the strategies and select the best strategy without consideration of robustness to uncertainty. A latin hypercube sampling experimental design and stochastic dominance testing were utilised to determine the preferred strategy when robustness to uncertainty is considered.

Findings

The findings of this work show that shared GKCS outperforms other strategies when robustness is not considered. However, when robustness of the strategies to uncertainty in the production environment is considered, the results of our research show that the dedicated EKCS is preferred. The effect of system bottleneck location on the inventory accumulation behaviour of different strategies is reported and this was also observed to have a relationship to the nature of a PCS's kanban information transmission.

Practical implications

The findings of this study are directly relevant to industry where increasing market pressures for product diversity require operating multi‐product production lines with negligible set‐up times. The optimization and robustness test approaches employed in this work can be extended to the analysis of more complicated system configurations and higher number of product types.

Originality/value

This work involves further investigation into the performance of multi‐product kanban‐like PCS by examining their robustness to common sources of uncertainties after they have been initially optimized for base scenarios. The results of the robustness tests also provide new insights into how dedicated kanban card allocation policies might offer higher flexibility and robustness over shared policies under conditions of uncertainty.

Article
Publication date: 1 March 1985

G. Boothroyd, P. Dewhurst and C.C. Lennartz

The authors assess the suitability of different types of parts presentation devices in a variety of robotic assembly situations.

Abstract

The authors assess the suitability of different types of parts presentation devices in a variety of robotic assembly situations.

Details

Assembly Automation, vol. 5 no. 3
Type: Research Article
ISSN: 0144-5154

Article
Publication date: 1 May 1995

Mohammad Z. Meybodi

Presents a hierarchical production planning (HPP) model thatintegrates aggregate‐type planning, family disaggregate planning,lot‐sizing, job scheduling and evaluation of the final…

2084

Abstract

Presents a hierarchical production planning (HPP) model that integrates aggregate‐type planning, family disaggregate planning, lot‐sizing, job scheduling and evaluation of the final production plans into a complete planning and scheduling system. In‐corporation of a simple heuristic scheduling algorithm into the HPP model is the primary contribution. The scheduling routine schedules the jobs based on just‐in‐time (JIT) concept and provides detailed shopfloor information such as job tardiness, bottleneck work centres, capacity level, inventory or shortage level and number of set‐ups. This information is critical for effective shopfloor management. Experimental results indicate that the performance of the present model is better than the existing models in general. However, the model is truly superior under tight capacity conditions.

Details

International Journal of Operations & Production Management, vol. 15 no. 5
Type: Research Article
ISSN: 0144-3577

Keywords

Article
Publication date: 1 February 1992

N. Singh and J.K. Brar

Provides a comprehensive review of various modelling approachesrelated to Just‐in‐Time (JIT) manufacturing. JIT is essentially aphilosophy for reducing lead time as well as…

Abstract

Provides a comprehensive review of various modelling approaches related to Just‐in‐Time (JIT) manufacturing. JIT is essentially a philosophy for reducing lead time as well as excessive work‐in‐progress inventories. Based on this concept a number of techniques have been developed for the design, planning, scheduling and control of JIT manufacturing systems. Reports on a comparative study of these approaches for JIT manufacturing along with the conventional manufacturing approaches and alternative systems for JIT manufacture. Explores future research areas.

Details

International Journal of Operations & Production Management, vol. 12 no. 2
Type: Research Article
ISSN: 0144-3577

Keywords

Article
Publication date: 1 July 1992

Regine Slagmulder and Werner Bruggeman

The literature offers a variety of different views on theinvestment decision process for flexible manufacturing technologies, butthere seems to be no consensus about what are…

Abstract

The literature offers a variety of different views on the investment decision process for flexible manufacturing technologies, but there seems to be no consensus about what are really the key characteristics of the decision‐making process which guarantee successful advanced manufacturing technology projects. Describes and analyses the investment decision process for a set of investment projects, based on field research conducted in six manufacturing companies, and reveals some of these critical determinants.

Details

International Journal of Operations & Production Management, vol. 12 no. 7/8
Type: Research Article
ISSN: 0144-3577

Keywords

Article
Publication date: 8 October 2018

Binghai Zhou and Qiong Wu

The balancing of robotic weld assembly lines has a significant influence on achievable production efficiency. This paper aims to investigate the most suitable way to assign both…

Abstract

Purpose

The balancing of robotic weld assembly lines has a significant influence on achievable production efficiency. This paper aims to investigate the most suitable way to assign both assembly tasks and type of robots to every workstation, and present an optimal method of robotic weld assembly line balancing (ALB) problems with the additional concern of changeover times. An industrial case of a robotic weld assembly line problem is investigated with an objective of minimizing cycle time of workstations.

Design/methodology/approach

This research proposes an optimal method for balancing robotic weld assembly lines. To solve the problem, a low bound of cycle time of workstations is built, and on account of the non-deterministic polynomial-time (NP)-hard nature of ALB problem (ALBP), a genetic algorithm (GA) with the mechanism of simulated annealing (SA), as well as self-adaption procedure, was proposed to overcome the inferior capability of GA in aspect of local search.

Findings

Theory analysis and simulation experiments on an industrial case of a car body welding assembly line are conducted in this paper. Satisfactory results show that the performance of GA is enhanced owing to the mechanism of SA, and the proposed method can efficiently solve the real-world size case of robotic weld ALBPs with changeover times.

Research limitations/implications

The additional consideration of tool changing has very realistic significance in manufacturing. Furthermore, this research work could be modified and applied to other ALBPs, such as worker ALBPs considering tool-changeover times.

Originality/value

For the first time in the robotic weld ALBPs, the fixtures’ (tools’) changeover times are considered. Furthermore, a mathematical model with an objective function of minimizing cycle time of workstations was developed. To solve the proposed problem, a GA with the mechanism of SA was put forth to overcome the inferior capability of GA in the aspect of local search.

Details

Assembly Automation, vol. 38 no. 4
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 1 March 1988

MAJOR reductions in the number of set‐ups per job combined with very high levels of accuracy and a reduction in non conformance these are the major benefits to accrue from the…

Abstract

MAJOR reductions in the number of set‐ups per job combined with very high levels of accuracy and a reduction in non conformance these are the major benefits to accrue from the installation of two Maho MC 600 horizontal spindle machining centres at Birmingham aerospace industry sub‐contractor Gainsborough Precision.

Details

Aircraft Engineering and Aerospace Technology, vol. 60 no. 3
Type: Research Article
ISSN: 0002-2667

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), manufacturing…

2110

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

Keywords

Article
Publication date: 14 June 2019

Binghai Zhou and Qiong Wu

The extensive applications of the industrial robots have made the optimization of assembly lines more complicated. The purpose of this paper is to develop a balancing method of…

Abstract

Purpose

The extensive applications of the industrial robots have made the optimization of assembly lines more complicated. The purpose of this paper is to develop a balancing method of both workstation time and station area to improve the efficiency and productivity of the robotic assembly lines. A tradeoff was made between two conflicting objective functions, minimizing the number of workstations and minimizing the area of each workstation.

Design/methodology/approach

This research proposes an optimal method for balancing robotic assembly lines with space consideration and reducing robot changeover and area for tools and fixtures to further minimize assembly line area and cycle time. Due to the NP-hard nature of the considered problem, an improved multi-objective immune clonal selection algorithm is proposed to solve this constrained multi-objective optimization problem, and a special coding scheme is designed for the problem. To enhance the performance of the algorithm, several strategies including elite strategy and global search are introduced.

Findings

A set of instances of different problem scales are optimized and the results are compared with two other high-performing multi-objective algorithms to evaluate the efficiency and superiority of the proposed algorithm. It is found that the proposed method can efficiently solve the real-world size case of time and space robotic assembly line balancing problems.

Originality/value

For the first time in the robotic assembly line balancing problems, an assignment-based tool area and a sequence-based changeover time are took into consideration. Furthermore, a mathematical model with bi-objective functions of minimizing the number of workstations and area of each station was developed. To solve the proposed problem, an improved multi-objective immune clonal selection algorithm was proposed and a special coding scheme is designed.

Details

Engineering Computations, vol. 36 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 March 2003

Antonio C. Caputo and Pacifico M. Pelagagge

Describes the reengineering of a production line for household heating tubular radiators, assuming as a reference scenario the facility of one of the leading Italian…

1646

Abstract

Describes the reengineering of a production line for household heating tubular radiators, assuming as a reference scenario the facility of one of the leading Italian manufacturers. After a preliminary characterization of products and manufacturing process, a thorough analysis of the production system has been carried out in order to highlight current problems and improvement strategies in the light of lean manufacturing concepts. Subsequently, suggests some corrective actions and also assesses their expected effectiveness in economic terms. In particular, improvement possibilities have been found in the areas of internal logistics through streamlining of materials flow and layout modifications, as well as process quality increase. Reengineering activities are especially aimed towards layout optimization mainly by resorting to a U‐shaped cell‐based architecture. Further, the reduction of rework percentage during the assembly phase has been pursued by properly modifying the operations sequence and through integration of a new automated testing station in the production line.

Details

Integrated Manufacturing Systems, vol. 14 no. 2
Type: Research Article
ISSN: 0957-6061

Keywords

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