A FRAMEWORK FOR UNDERSTANDING CELLULAR MANUFACTURING SYSTEMS Sílvio do Carmo Silva, Anabela Carvalho Alves Minho University, Campus de Gualtar, 4710 – 057 – Braga, Portugal phone:+351+253 604745, fax: +351 253 604741, e-mail scarmo@dps.uminho.pt Minho University, Campus de Azurém, 4800 – 058 – Guimarães, Portugal phone:+351+253 510260, fax:+351 253 510268, e-mail anabela@dps.uminho.pt Many practical benefits, such as superior quality of products and short manufacturing lead times, are usually associated with Cellular Manufacturing. These and other benefits can lead to important competitive advantages of companies. However, to fully achieve these benefits there is a need for an evolution from the traditional concept of CM to the more comprehensive one, which we call Product Oriented Manufacturing. Here systems are dynamically reconfigured for total manufacturing of complete products, not parts only. In this paper, we make a contribution to better understand the nature of cells and POM Systems. Thus a classification framework is presented of the different types of cells that might be formed and seen as building blocks for POMS. 1. INTRODUCTION Traditionally a manufacturing cell has been identified as a system dedicated to the manufacture of a family of identical parts. The manufacture based on a setting of such cells is usually referred to as Cellular Manufacturing. A more comprehensive definition of a manufacturing cell points to a manufacturing system that groups and organizes the manufacturing resources, such as people, machines, tools, buffers, and handling devices, dedicated to the manufacture of a part family, or the assembly of a family of products, with identical or very similar manufacturing requirements. Therefore important economies of scale can be obtained producing for economies of scope, i.e. for a variety of products. This approach of identical or very similar processing of similar objects is known as Group Technology (GT) (Gallagher, 1973). It is for this reason that manufacturing systems based on cells are frequently associated with GT. The problems to be solved in Cellular Manufacturing Systems (CMS) can be classified in cell design and cell operation problems. Arvindh and Irani (1994) identified four classes of problems to be solved in the design of cellular manufacturing cells, namely: machine group and part family formation, machine duplication, intra-cell layout and inter-cell layout . These