Cellular manufacturing versus a hybrid system: a comparative study

European Journal of Operational Research, 2000

In this paper, the performance of hybrid cellular manufacturing (CM) systems is compared with that of functional layouts that use traditional job shop procedures as well as part family scheduling rules, under a variety of shop operating conditions. Unlike much of past research in group technology (GT), this work examines the entire shop floor, in which the CM systems comprise cells and a remainder shop organized as a functional layout. The experimental factors investigated include: the system (two functional layouts and five hybrid systems); setup factor, a surrogate for the degree of part family similarities; scheduling rule, which includes both job shop and part family-oriented rules; and lot size. The performance measures used were flow time, work-in-process inventory, machine utilization and flow ratio. Several findings emerged that form a useful addition to the literature. While part family-oriented scheduling rules significantly outperformed job shop rules, little difference was detected among the former. The results also indicated that the performance of the remainder shop deteriorated with increasing conversion, due to erosion of pooling synergy.

2021

Cellular manufacturing has tested positive in significantly reducing material handling and setup time as compared to a job shop, but it falls behind job shop in terms of flexibility. In this thesis a new system is proposed that takes advantage of the flexibility of a job shop while it keeps the setup time at a reduced level. This new system is referred to as hybrid system. In this thesis the performance of the proposed hybrid system is compared to the conventional cellular manufacturing system. Both systems are evaluated within a cellular layout and utilize group sheduling rules DDSI (due date truncated shortest processing time) and MSSPT (minimum setup shortest processing time). A simulation model, with random due dates and quantities is developed and tested. Performance measures are mean flowtime, tardiness and earliness. Overall results indicate that, in terms of mean flowtime and tardiness, the hybrid system outperforms the cellular system when the MSSPT rule was applied, while ...

2008

Cellular Manufacturing (CM) system has been recognized as an efficient and effective way to improve productivity in a factory. In recent years, there have been continuous research efforts to study different facet of CM system. The literature does not contain much ...

April 2021, 2021

Shorter product life cycles, unpredictable demand patterns and the ever-shrinking time to market, have been constantly keeping the manufacturing firms under a lot of pressure. To face these challenges the manufacturing organizations have been shifting to Cellular Manufacturing (CM) due to its benefits of reducing manufacturing costs, increasing flexibility and delivering orders on time. Despite having several benefits, designing a Cellular Manufacturing System (CMS) for a real-life application is a tough ask. The main challenge is the part-machine grouping in cells. It becomes even more challenging when the group scheduling (GS) problem is handled alongside the part-machine clustering. To take up this challenge, an integrated model is developed during this research which handles the machine-part grouping and the GS problems, simultaneously. To optimize the multiple objectives of maximizing Grouping Efficacy (GE) and minimizing Makespan (Cmax), concurrently, a Hybrid Genetic Algorith...

2010 IEEE International Conference on Industrial Engineering and Engineering Management, 2010

In mid-volume, mid-variety production cellular manufacturing systems have many advantages compared to systems using process layout. But their performance superiority is found to diminish when the demand becomes unstable. Adaptive cellular systems are designed, especially for dynamic demands. Here, the performance of an adaptive cellular system is compared to that of a system using process layout, using simulation, when they execute production in a multi-period dynamic demand environment. It is found that the adaptive design perform comparatively better than process layout in terms of reduced work-in-process inventory and manufacturing lead time. The managing of semi-finished parts at the end of a period, and the effort of relocation of machines after every period are the disadvantages of adaptive cellular systems.

2007

The manufacturing sector has become increasingly competitive as markets become more globalized. Consequently, there have been major shifts in the design of manufacturing systems using innovative concepts. The adoption of cellular manufacturing (CM) has received considerable interest from both practitioners and academicians that offers several major advantages, including reduction in lead times and work-in-process inventories, and reduction of setup times due to similarity of part types produced. Reorganizing the cell layout to meet the changed needs, however, may be time-consuming and costly. Further, if these changes occur very frequently, reconfiguration becomes impracticable or even infeasible. In such an environment, it appears that manufacturers tend to adopt a traditional job shop layout combined with the benefits of cellular manufacturing systems. The research in this paper considers the new concept of virtual cellular manufacturing (VCM). This is in an attempt to increase the efficiency of manufacturing operations by varying the methods of production. Embedded in this paper are the principles of group technology (GT) as it applies to processing families of parts that have similar manufacturing operations. The problem of family oriented scheduling to take further setup efficiencies of traditional CM that combines with the routing flexibility of a functionally organized job shop is also entrenched. Decisions for pooling of jobs into families, release of part families to the shop and dispatching of jobs to individual machines will lead to further improvement in job flow time. In this paper a case study was used to demonstrate new concept of CM. Emphasis will be placed to compare the model performance in terms of setup and job flow times.

1998

A limitation of Group Technology (GT) based cellular manufacturing systems is that their limited routing flexibility offsets the setup and material handling efficiencies they offer. Virtual Cellular Manufacturing (VCM) systems do not encounter the problem of limited routing flexibility but do not yield the same efficiencies as GT based cellular systems. This study compares the performance of a GT based cellular manufacturing system that utilizes operations overlapping to further improve material flow efficiency with that of a virtual cellular manufacturing system. Results suggest that while the use of operations overlapping in a GT based cellular manufacturing system can to some extent compensate for the system’s low routing flexibility, it cannot fully overcome the high flow time variance that results from the permanent dedication of machine resources. As a result, GT based cellular manufacturing performs comparably to VCM only under a limited set of conditions.

Hybrid cellular manufacturing (CM) systems are well represented in manufacturing practice and thus constitute a fertile area of research. This work studies the performance of hybrid CM systems by means of data envelopment analysis (DEA). Since DEA allows for simultaneous analysis of multiple inputs and outputs of a system, it provides for a comprehensive investigation of CM performance under a wide variety of experimental conditions. For the purpose of measuring system efficiency, the number of machines and the degree of set up reduction are used as inputs, and flow time, work-in-progress (WIP) inventory and job tardiness are used as outputs. Results indicate that the hybrid systems in the study perform best at a low to intermediate degree of cellularization

Manufacturing industries are under intense pressure from the increasingly competitive global marketplace. Shorter product life cycle, time-to-market and diverse customer needs have challenged manufacturers to improve the efficiency and productivity of their production activities. Manufacturing systems should be able to adjust or respond quickly to adopt necessary changes in product design and product demand without major investment. Traditional manufacturing systems, such as, job shops and flow lines are not capable of satisfying such requirements. Although a cellular manufacturing system (CMS) provides great benefits, the design of CMS is complex for real life problems. Existing design methods employ simplifying assumptions, which often deteriorate the validity of the models used for obtaining solutions. In this paper, a method of flexible CMS has been discussed and a case study is presented in a reputed gear manufacturing industry, which converted functional layout into CMS. There was reduction of Rs 1 05 234.84 in the total cost per week after converting functional layout into CMS. The CMS worked successfully with two different machines-parts combinations. Keywords : Cellular manufacturing system; Simulated annealing; Cell configuration; Cost reduction

2017

A big challenge of today’s batch production industries is to offer fast delivery of a variety of products to the customer. To meet this challenge, manufacturing industries are turning to cellular manufacturing system (CMS). CMS is based on group technology approach where workstations are arranged in form of manufacturing cells and part families are assigned to these cells. Each manufacturing cell performs all or most of the operations required by part families. Primary purpose of CMS is to reduce setup time, cycle time, and improve machining utilization. The important steps in CMS are identifying part families, formation of manufacturing cells and assigning part families to the cells. This paper reviews literature on cellular manufacturing system. Different approaches such as heuristic, meta-heuristics, mathematical programming methods etc. have been discussed.