Nancy Lea Hyer

Cellular manufacturing in the U.S. industry: a survey of users

This paper reports the findings of a survey study of 32 U.S. firms involved with cellular manufacturing. Areas covered include the reasons for establishing cells, benefits achieved, types and sizes of cells, extent of cellularization in the plants, methods used to design the cells, changes to planning and control systems, labour-related issues and important experiences gained by the companies. The data presented here were collected as part of a larger study of various group technology (GT) applications in which 53 companies participated. GT applications other than cellular manufacturing are described in Hyer and Wemmerlov, 1989, Group technology in the U.S. manufacturing industry: a survey of current practices, International Journal of Production Research.

Procedures for the Part Family/Machine Group Identification Problem in Cellular Manufacturing

Abstract One of the first, and most important, problems faced in the design of a cellular manufacturing system is the identification of part families and machine groups and the simultaneous or subsequent evaluation of the associated cell properties. This cell formation problem is embedded in a larger cell design process. This article first discusses the general cell design process and its objectives and then proposes a framework for structuring the cell formation problem, which encompasses four basic solution approaches. These approaches are based on the fundamental ways part families and machine groups are identified and matched within the cell formation process. The framework is then used to classify descriptive and analytic procedures for the part family/machine group identification problem found in the literature. In all, over 70 such contributions are categorized and briefly reviewed. Promising procedures are identified and areas where additional research is needed are highlighted. It can be concluded that cell formation, despite the reliance on computerized procedures, is a process that is difficult to formalize and that requires a large portion of human insight and decision making.

Research issues in cellular manufacturing

Abstract Both industry and academia are currently devoting considerable interest to cellular manufacturing systems. Despite this growing attention, the existing literature does not adequately address a number of issues related to the successful adoption of these systems. This paper identifies a large number of research topics related to cellular manufacturing, discusses the need for their investigation, and suggests appropriate methodologies for their study. This research agenda is presented in the context of four important decision areas for new technology adoption—applicability, justification, system design, and implementation. The volume and variety of topics identified allow us to conclude that cellular manufacturing is an area with many researchable issues, spanning several academic disciplines, and requiring a multitude of research methodologies.

The human factor in cellular manufacturing

Abstract Recently, Group Technology (GT) as a batch manufacturing innovation has commanded much research attention and pragmatic interest. This approach to small lot production is based on identifying and exploiting similarities. By grouping items which share common traits, GT facilitates the rationalization of activities in a wide variety of functional areas including purchasing, design, and manufacturing. When GT is used in manufacturing one potential application involves the creation and operation of production cells. A production or manufacturing cell is a group of functionally dissimilar machines that are placed together and dedicated to the manufacture of a specific range of component parts. The usefulness of cellular manufacturing is demonstrated by the impressive catalog of benefits reported by its users both in the US and abroad. Reductions in work-in-process and finished goods inventories, decreases in production lead time, better delivery performance, improved product quality, and an overall increase in productivity are but a few of the benefits reportedly accruing to the use of cells. While it appears that cellular manufacturing can significantly improve the operation of batch production, an important component of the GT cellular production system has, unfortunately, been overlooked. Little study has been devoted to the human aspects of the use of production cells. The research reported in this paper attempts to fill this void by systematically examining the effect of cellular production on batch manufacturing employees. The research site was a medium size plant in which a portion of the functionally arranged facilities had recently been converted to a cellular layout. Both functional and cellular workers responded to a questionnaire designed to assess employee perceptions of their jobs, their job satisfaction, and their performance. In contrast to the findings of earlier (ethnographic) studies, cellular manufacturing employees did not perceive greater autonomy, significance, identity, or cohesiveness in their jobs than workers in traditional functional jobs. Cell workers also were as satisfied with their jobs, supervision, and advancement opportunities as non-cell workers, but were more satisfied with their pay. Supervisory ratings of performance did not vary between groups. The major contributions of this article are threefold. First, this research represents the first attempt to scientifically evaluate the human impact of cellular manufacturing. Second, in contradicting the findings of earlier descriptive studies, all of which emphasize the very positive human consequences of cellular production, the need for additional research which challenges initial intuitive presumptions is clearly indicated. Third, and perhaps most importantly, the findings of this exploratory study suggest that cellular manufacturing does not have a negative impact on worker performance, attitudes, or satisfaction. A ramification of this is that reductions in work-in-process and finished goods inventories, decreases in production lead time, and improved overall productivity which reportedly accompany the implementation of cellular manufacturing may be achieved without any human fallout.

The potential of group technology for U.S. manufacturing

Group Technology (GT) is an innovative approach to batch production which seeks to rationalize a variety of aspects of the conversion process by recognizing and exploiting the underlying sameness which exists among component parts, end items, raw materials and so forth. The majority of GT applications, however, focus on identifying and capitalizing on component part similarities. The central theme of GT when applied to this class of items is the formation of part families based on design or manufacturing similarities (or both). Although the basic principles of GT were described and applied overseas as early as 1950, it is only in the past ten years that any significant and sustained U.S. interest in GT has surfaced. In an effort, first, to determine the status of GT use in the U.S. and, second, to provide some insights as to the desirability of GT for U.S. manufacturers, data was collected on twenty U.S. firms known to use this innovation. A fifteen page questionnaire was employed to gather information on (1) the characteristics of these firms which use GT, (2) the ways in which GT has been applied at these companies and (3) the costs and benefits of these GT programs. The results of this survey, described below, provide an overview of GT practices in a sample of U.S. firms and indicate the potential usefulness of this innovation for a broad spectrum of U.S. manufacturers. The survey responses indicate that GT is a multifaceted tool which can be applied to a variety of problems in a variety of industrial settings. GT has been adopted by both large and small installations involved in the manufacture of metal items produced in small to medium quantity lots. Although no applications were identified outside metal working, the range of metalworking industries in which GT had been implemented is quite broad. Universally, GT was adopted in response to a particular problem or set of problems. Frequently, the need to curb excessive lead times motivated firms to introduce GT. In terms of implementing and using GT there were a number of interesting findings. First, the survey results confirm that GT is more than cellular manufacturing. In fact, the most popular application of GT was in manufacturing engineering, particularly as an aid in rationalizing the process planning function. Seventy-five percent of the firms had used GT in manufacturing engineering, while fifty-five percent had set up one or more production cells and an equal number had applied GT to product design. A second interesting finding was that, for the majority of firms, informal procedures for identifying and grouping similar items (i.e. by visual inspection or informed judgement) proved inadequate for pursuing GT applications. Consequently, eighty-five percent of the respondents noted that formal classification and coding schemes had been used to aid in identifying and exploiting item similarities. The survey also yielded interesting results with respect to the problems encountered in implementing GT. The firms reported that regardless of the type of application (i.e., product design, manufacturing engineering or cellular manufacturing), human resistance to change was the most serious impediment to successfully introducing GT. This obstacle could be surmounted, in most instances, by GT education and by involving those affected by GT as early in the implementation process as possible. A number of other problems specific to the type of GT application were also noted. With regard to the relative ease of implementing GT in various areas, the respondents generally agreed that establishing cells is fraught with more difficulties than are GT applications in manufacturing engineering or product design. With respect to costs and benefits, 85% of the firms reported that the actual benefits from GT met or exceeded their anticipated benefits. Specific savings frequently mentioned included reduced lead times and easier preparation of process plans. Costs for planning the GT program and for purchasing additional computer hardware and software were the most commonly cited GT-related expenses. In terms of prerequisites for success in implementing GT, the overwhelming majority of respondents agreed that two elements are essential. The first is GT education for all those (managers, supervisors and line personnel) who are affected by the changes that accompany GTs introduction. The second critical factor is top managements commitment to GT principles and support for the personnel involved in directing the GT efforts. Thus, to the extent that the firms included here are representative of a broader spectrum of U.S. manufacturers, one can conclude that in the presence of top management encouragement and a commitment to GT education, batch manufacturers involved in metalworking and facing any of a variety of problems could benefit from putting into practice GT principles.

A socio-technical systems approach to cell design: case study and analysis

Abstract There exists a large and growing body of academic research exploring various facets of cell design. Most of this research adopts a micro-level focus, investigating one or a few issues within this large and complex process. Further, most of this research can be characterized as technically focused, giving only limited attention to the significant human dimensions. This has led to a situation where we know a great deal about certain steps in technical design of cells (for example, how to form machine groups and parts families among small data sets), but lack a well-developed and broadly-focused theory of cell design and its human consequences. Based on a review of both existing cell design approaches and socio-technical systems (STS) theory literature, this paper proposes a comprehensive model of cell system design that considers both technical and social dimensions. We illustrate the viability of this model via an observational case study of a very successful cell manufacturing implementation effort in a Fortune 500 company. We highlight the ways in which STS principles influenced and enhanced the cell system design and draw conclusions about the elements of cell system design which appear to be the most significant determinants of sustainable success.

Research needs in managing factory automation

Abstract The subject of factory automation is a critical one for all business functions, with the potential of creating an entire upheaval in the fields of accounting, finance, marketing, general management, and most significantly, operations management. Totally new ways of managing a business are likely, but it is not yet clear what these ways may be. In spite of the tremendous implications of these new technologies, little research is being conducted in this area. A panel session exploring this topic was thus offered at the 1984 Toronto meeting of the American Institute for Decision Sciences. This article presents the results of that session. The intent of the article is to foster research interest in this area and identify the extensive opportunities available. The article reviews the extant literature concerning the management of factory automation and identifies the gaps in our knowledge where research is needed. Factory automation as defined here is intended to include the areas of both hard automation (CAD/CAM, robotics, FMS, etc.) and soft automation (such as MRP II, group technology, MAP, data networking). Research issues are divided into three major topic areas for ease of discussion: strategic issues, justification issues, and implementation issues. The strategic area encompasses the subjects of corporate strategy and its tie with manufacturing strategy, firm characteristics of leading-edge users of automation, the effect of learning and experience with automation, the concept of “synergy” among automation technologies, technology transfer, and implementation strategy. The justification issues are divided into benefit, cost, and risk aspects. The present inadequacy of economic justification techniques for automation systems and the pros and cons of alternative approaches are explored. The consideration of differing types of automation and their possible need for differing justification techniques is also discussed. For both benefits and costs, the quantification problem is a major issue, particularly with benefits believed to improve the effectiveness of operations, rather than their efficiency (a major advantage of the automation technologies, it is often claimed). Another major issue here is the pre- and postautomation comparison, requiring accurate and thorough manufacturing audit techniques. The risks in automation can be tremendous. Whether this can be reduced through incremental automation, or other approaches, is a very important question. The nature of the risks-technological, financial, sociological—is also an important subject for research, as well as methods to deal with each type. Topics in the implementation area include procedural aspects, human aspects, interface/infrastructure aspects, and measurement and reward aspects. In general, the nature of the automation implementation process, and its solution, is a critical research area that is confounded with multiple factors. There is a need for research to determine if such a thing as a “best” implementation path exists for specific technologies and firms. How does a firm know if it is “ready” for automation, and which automation technology to start with? The effect of automation on workers and management is an important research question. And in addition, what are the effects of these employees on the implementation process? And it will be necessary to know how jobs change under automation, for both line and staff. Research is also needed to determine how automation will affect the way the firm does business, how interdepartmental coordination will be affected, and whether there will even be departments. If automation is implemented piecemeal, can the pieces later be tied together? What will be the problems? Managers need to know if new measurement and reward systems will be needed for workers, or perhaps even more important, for the managers. Will incentives need to be increased, or changed in some other fashion, for managers to be willing to take the risks involved in automation? Last, some advice is given to the potential researcher in this area. Approaching this subject in a way that yields meaningful research, helpful to real managers currently struggling with these problems, is important since real firms are our primary research laboratories in this field. For example, case studies, interviews, surveys, and conceptual development are important early tools in this area compared to the traditional model building and analysis techniques that have historically characterized operations management.

An expert system based approach to manufacturing cell design

The design of cellular systems is a complex, multi-criteria and multi-step process which can have significant implications for the entire organization. Most research in this area focuses on the formation of pan families and associated machine groups, one step in the cell design process. Numerous quantitative techniques have been developed to address this part-family/machine group formation problem. Existing approaches include math programming, algorithms for matrix diagonalization, the application of network modelling and the use of similarity coefficients. These mathematically-oriented techniques can handle a relatively limited set of quantitative objectives and. in addition, require many simplifying assumptions. For this reason, the solutions generated by these techniques are of limited usefulness in actual cell design. This paper proposes an expert system approach to cell system design. The starting point for the expert system is the initial solution generated by traditional mathematical techniques. Ba...

The Human Factor in Group Technology: An Analysis of the Effects of Job Redesign.

The effects of group technology and cellular manufacturing on batch manufacturing employee perceptions of their jobs, satisfaction and performance were examined using a quasi-experimental design. In contrast to earlier ethnographic studies, cellular manufacturing employees did not perceive greater autonomy, significance, identity and cohesiveness in their jobs than workers in traditional functional jobs. Cell workers also were as satisfied with their jobs, supervision or advancement opportunities as non-cell workers but more satisfied with their pay.