Summary: Dynamic allocation of stochastic capacity among competing activities in a just in time manufacturing environment is addressed by optimal flow control. Optimal policies are characterized by generally intractable Bellman equations. A near-optimal controller design technique is proposed. It provides an approximate numerical solution to the Bellman equation, a tight lower bound for the optimality gap of tractable, near- optimal controller designs, and a building block for improved, near- optimal controller designs that rely on the decomposition of a multiple part-type problem to smaller (two or three part-type) problems. Computational experience is reported for two and three part-type problems.