Colored Petri Net Modeling of Metal Distribution in a Job Shop Iron Foundry: Improving Flow in a Pull System with Perishable In-Process Inventory

摘要

Colored Petri nets with time are used to model the dynamic behavior of a foundry job shop to address the basic issue of matching molten iron production capability with casting demands. The objective is to achieve the maximum iron throughput per day for the chosen configuration. The fundamental pulling forces in the system are analyzed and then combined to provide a picture of the overall pulling behavior on the demand side of the system. A necessary condition to avoid deadlock is developed and used to develop the best demand pattern. This pattern of demand is then compared to the supply capability of the furnaces. The fundamental parameters of the system are identified and analyzed and a sufficient condition for deadlock avoidance is developed. The conditions leading to finding the best compromise values for the decision variables are investigated.