A review of cellular manufacturing assumptions, advantages and design techniques

Abstract

Abstract For years the industrial job shop has faced an increase in complexity and a decline in productivity due in part to an increase in part mix, volume of parts, plant size, machine production rates, and part complexity. One result of the increased complexity and reduced productivity is the development of Group Technology and cellular manufacturing which seek to eliminate or minimize complexity and to improve or maximize productivity. Group Technology can be defined as bringing together and organizing (grouping) common concepts, principles, problems, and tasks (technology). Cellular manufacturing is the physical division of the functional job shop's manufacturing machinery into production cells. Each cell is designed to produce a part family. A part family is defined as a group of parts requiring similar machinery, machine operations, and/or jigs and fixtures. The parts within the family are normally transformed from raw material to finished part within a single cell. For the successful implementation of cellular manufacturing, a set of assumptions should be adhered to. These assumptions are related to the design, operation and control of the system. There are numerous advantages associated with cellular manufacturing: • -Reduced material handling • -Reduced tooling • -Reduced set-up time • -Reduced expediting • -Reduced in-process inventory • -Reduced part makespan • -Improved human relations • -Improved operator expertise. There are also some disadvantages associated with cellular manufacturing: • -Increased capital investment • -Lower machine utilization. Numerous techniques are available to configure or reconfigure a cellular manufacturing system. Interestingly, nearly all published techniques come from Great Britain and Europe. Mitrofanov, in Russia, was an early proponent of cellular manufacturing with his composite component approach. J. L. Burbidge's Production Flow Analysis (PFA) was one of the first methodologies developed and subsequently published in the free world. It is also probably the most well known and most widely accepted method. In the last few years, Burbidge's PFA has undergone considerable revision and updating in an attempt to eliminate much of the original manual sorting and calculations. Computerization has been applied in an attempt to determine the key machines. Burbidge has termed this new concept nuclear synthesis [4]. El-Essaway and Torrance incorporated many of Burbidge's material flow simplification concepts in their computerized Component Flow Analysis. V.B. Solaja and S.M. Urosevic have developed a method in which cells are designed based on optimizing three criteria: Maximizing machine utilization, minimizing the part operation time, and minimizing capital invested. In 1972, McAuley presented a method of creating cells based on part classification and coding and on a similarity coefficient. A.S. Carrie and J. Mannion reported in 1975 on a cell design procedure which is based on forcing the cell to resemble a flow shop. There have been several other design techniques presented in the open literature. Each technique has specific capabilities and limitations. In summary, there are numerous techniques developed to form a traditional job shop into a cellular manufacturing system. But, there are very few documented applications or techniques based on optimal seeking analytical development. It is apparent that although techniques are known, they have not been developed for easy industrial application and in many cases do not have a strong enough analytical base to warrant implementation. Therefore although obvious advantages to Group Technology and cellular manufacturing exist and methods to create a cellular manufacturing system are available, these methods are problematic because design or redesign of a job shop to a cellular manufacturing system remains rather difficult and theoretical.