Discrete Event Simulation for Supporting Production Planning and Scheduling Decision in Job Shop Facilities

This paper describes a new simulation-based production planning and scheduling (PPS) system for use in managing a job shop manufacturing facility. A job consists of a process flow that contains all tasks that must be accomplished in order for the job to be complete. Each task can be performed in several workstations (resources) of varying performance. The order in which the task will be performed, as well as the resources that will be involved in the process is called a schedule and it is specified by the shop managers. However, when creating a new schedule, it is difficult to predict and account for the randomness in the system as well as the contention for facility resources that is likely to occur. The PPS system will accept a proposed job schedule and, by using simulation, will resolve the resource contention. It will produce a realizable job schedule that allows the user to see the impact of resource contention on the shop floor. This paper describes the high-level design of the PPS system, with an emphasis on the input and output sub-systems.