AbstractThe paper describes a simulation model that was built to predict the production output of a printed circuit-board manufacturer. Such a prediction with traditional forecasting tools is difficult owing to varying lot sizes, designs, processing time, product mix, machining capacity and fluctuating work-force. The model was built with discrete-event orientation using SIMPLE_1 simulation language. Model-validation was made over a period of 1 month by comparing the simulation and actual outputs as well as the supervisor's predictions. The model was later used to study the effects of varying manning levels and equipment capacities on output, as well as to evaluate proposed changes to the existing system.