This paper investigates the information processing function of a computer-integrated manufacturing (CIM) system, which is usually neglected by engineers when they study the performance of a manufacturing system. The feasibility of developing a complete simulation model which would include both the operational and information processing functions is therefore considered. In order to achieve this, a typical pick-and-place manufacturing cell was considered in which 46 devices were connected to a local area network (LAN). Two independent simulation tools, SIMAN* and L-NET†, were used in order to develop the complete model. The model was evaluated and used to study the performance of the pick-and-place cell using different communication protocols such as the IEEE 802.3 carrier sense multiple access with collision detection (CSMA/CD), IEEE 802.4 token bus and the IEEE 802.5 token ring. Results presented in this paper show that with careful design and simulation it is possible to develop a complete model which includes both operational and informational processing functions. Although the example of the pick-and-place cell is relatively simple the technique adopted could be applied to any CIM system. Results have also shown that for the pick-and-place cell considered in this paper an IEEE 802.3 CSMA/CD protocol operating at 10 Mbps would guarantee access to the network within the shortest station processing time.
Manufacturing cell formation in the case of multimanufacturing processes
