Machine Utilization Optimization in Manufacturing Systems

The four target criteria of lead time, scheduling deviation, work-in-progress (WIP), and utilization determine the objectives of production logistics. As a kind of typical queuing systems, optimization of performance measures is intractable to do in manufacturing systems. Fortunately, owing to its exellent characteristics, the convex optimization method can be very helpful. Based on the queuing theory, a nonlinear load optimal allocation model is proposed in this paper. A novel transformation of the optimization variables is also devised and the constraints are properly combined so as to make this model a convex one. The interior-point method for convex optimization is presented here as a computationally efficient tool. Finally, this model is assessed on a real case, from which such conclusions are drawn that the convex optimization can ensure the full utilization of machines and the least amount of WIP(work-in-progress); other performance measures of manufacturing systems may also be optimized in the similar way.