A top down and bottom manufacturing enterprise function view up approach to engineering using the

Abstract

In the contemporary global marketplace, manufacturing enterprises are increasingly required to be highly optimized. In order to re-engineer manufacturing systems to achieve this goal, enterprise engineering methods together with advanced support tools are required. In developing such methods it has often been suggested that a formal top down approach is difficult to map onto manufacturing resources, and that a bottom up approach will fail to accurately reflect the business needs of the enterprise. This paper describes and compares two enterprise engineering workbenches which are related, but take these two opposing approaches to system modelling: (1) A top down approach based on the CIM-OSA Reference Architecture which in its purest form prescribes that the modelling process begins with the identification of high level business goals, and; (2) A bottom up approach based on the creation of integrated systems through the coordination of manufacturing functional entities. The workbenches described primarily embrace the function view of an enterprise. They are part of a tool set which provides additional views. These additional tools are not discussed in this paper. This paper describes the facilities provided by the two CASE workbenches which both use petri-net models to describe system behaviour. The paper compares the approaches by describing their application during the design of a printed circuit board assembly line and concludes by identifying the appropriate use of each tool.