Group Technology
3. Group Technology / Cellular Manufacturing1
3.1 Introduction
As early as in the 1920ies it was observed, that using product-oriented departments to manufacture standardized products in machine companies lead to reduced transportation. This can be considered the start of Group Technology (GT). Parts are classified and parts with similar features are manufactured together with standardized processes. As a consequence, small "focused factories" are being created as independent operating units within large facilities. More generally, Group Technology can be considered a theory of management based on the principle that "similar things should be done similarly". In our context, "things" include product design, process planning, fabrication, assembly, and production control. However, in a more general sense GT may be applied to all activities, including administrative functions. The principle of group technology is to divide the manufacturing facility into small groups or cells of machines. The term cellular manufacturing is often used in this regard. Each of these cells is dedicated to a specified family or set of part types. Typically, a cell is a small group of machines (as a rule of thumb not more than five). An example would be a machining center with inspection and monitoring devices, tool and Part Storage, a robot for part handling, and the associated control hardware. The idea of GT can also be used to build larger groups, such as for instance, a department, possibly composed of several automated cells or several manned machines of various types. As mentioned in Chapter 1 (see also Figure 1.5) pure item flow lines are possible, if volumes are very large. If volumes are very small, and parts are very different, a functional layout (job shop) is usually appropriate. In the intermediate case of medium-variety, medium-volume environments, group configuration is most appropriate. GT can produce considerable improvements where it is appropriate and the basic idea
3.1 Introduction
As early as in the 1920ies it was observed, that using product-oriented departments to manufacture standardized products in machine companies lead to reduced transportation. This can be considered the start of Group Technology (GT). Parts are classified and parts with similar features are manufactured together with standardized processes. As a consequence, small "focused factories" are being created as independent operating units within large facilities. More generally, Group Technology can be considered a theory of management based on the principle that "similar things should be done similarly". In our context, "things" include product design, process planning, fabrication, assembly, and production control. However, in a more general sense GT may be applied to all activities, including administrative functions. The principle of group technology is to divide the manufacturing facility into small groups or cells of machines. The term cellular manufacturing is often used in this regard. Each of these cells is dedicated to a specified family or set of part types. Typically, a cell is a small group of machines (as a rule of thumb not more than five). An example would be a machining center with inspection and monitoring devices, tool and Part Storage, a robot for part handling, and the associated control hardware. The idea of GT can also be used to build larger groups, such as for instance, a department, possibly composed of several automated cells or several manned machines of various types. As mentioned in Chapter 1 (see also Figure 1.5) pure item flow lines are possible, if volumes are very large. If volumes are very small, and parts are very different, a functional layout (job shop) is usually appropriate. In the intermediate case of medium-variety, medium-volume environments, group configuration is most appropriate. GT can produce considerable improvements where it is appropriate and the basic idea
References: Askin, R.G., Standridge, C.R.: Modeling & Analysis Of Manufacturing Systems, John Wiley & Sons, 1993. B. Kernighan and S. Lin (1970): An Efficient Heuristic Procedure for Partitioning of Electrical Circuits, Bell System Technical Journal, 291-307. Internet sources on Opiz, KK3 und some methods, e.g.: • • • http://www.ielm.ust.hk/dfaculty/ajay/courses/ieem513/GT/GT.html Examples for metaheuristics: T.L. James, E.C. Brown, K.B. Keeling (2007): A hybrid grouping genetic algorithm for the cell formation problem, Computers and Operations Research, Volume 34 (7, July) 2059-2079 . Mahdavi, M.M. Paydar, M. Solimanpur, A. Heidarzade (2009): Genetic algorithm approach for solving a cell formation problem in cellular manufacturing, Expert Systems with Applications: An International Journal, Volume 36 (3, April) 6598-6604. T. Tunnukij, C. Hicks (2009): An Enhanced Grouping Genetic Algorithm for solving the cell formation problem, International Journal of Production Research, Volume 47 (7, Jan.) 1989 – 2007. D. Cao and M. Chen (2004): Using penalty function and Tabu search to solve cell formation problems with fixed cell cost, Computers & Operations Research, Volume 31 (1, Jan.) 21-37. J. Schaller (2005): Tabu search procedures for the cell formation problem with intra-cell transfer costs as a function of cell size, Computers and Industrial Engineering, Volume 49 (3, Nov.), 449 – 462. • • •