The potential of group technology for U.S. manufacturing
Authors: Lea Hyer Nancy 
Published: October 2002

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 GT's introduction. The second critical factor is top management's 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.