ABSTRACT
Group technology (GT) is a management philosophy that attempts to group products with similar design or manufacturing characteristics or both (Mitrofanov, 1983). Cellular manufacturing (CM) can be defi ned as an application of GT that involves grouping machines based on the parts manufactured by them. The main objective of CM is to identify machine cells and part families simultaneously, and to allocate part families to machine cells in a way that minimizes the intercellular movement of parts. To successfully implement the CM concept, analysts must develop the layout of machines within the cells to minimize inter-and intracellular material-handling costs. CM has been applied successfully in many manufacturing environments and can achieve signifi cant benefi ts (Black, 1983). Companies surveyed by Wemmerlov and Hyer (1989) have witnessed the following results:
Setup time reduction WIP inventory reduction Material-handling cost reduction Direct and indirect labor cost reduction Improvement in quality Improvement in material fl ow Improvement in machine utilization Improvement in space utilization Improvement in employee morale
The main difference between a traditional job-shop environment and a CM environment is in the grouping and layout of machines (Burbidge, 1963, 1992). In a job-shop environment, machines are typically grouped on the basis of their functional similarities (see Figure 6.1). In contrast, in a CM environment, machines are grouped into cells, with each cell dedicated to the manufacture of a specifi c part family (see Figure 6.2). Typically, the machines in each cell have dissimilar functions. The CM arrangement allows easier control of a cellular manufacturing system (CMS).
