Just-in-Time Smoothing Through Batching

This paper presents two methods to solve the production smoothing problem in mixed–model just–in–time (JIT) systems with large setup and processing time variability between different models the systems produce. The problem is motivated by production planning at a leading U.S. automotive pressure hose manufacturer. One method finds all Pareto–optimal solutions that minimize total production rate variation of models and work in process (WIP), and maximize system utilization and responsiveness. These Pareto–optimal solutions are found efficiently in polynomial time with respect to total demand by an algorithm proposed in the paper. The other method relies on Daniel Webster's method of apportionment for production smoothing, which produces periodic, uniform, and reflective production sequences that can improve operations management of the JIT systems. Finally, the paper presents the results of a computational experiment with the two methods.