Just-in-time policies for single-machine manufacturing flow controllers

Single, unreliable machine producing n part types is considered. Using a continuous flow model, conditions are found for the optimality of a just-in-time, or zero-inventory, policy via a stochastic coupling analysis. These conditions are proven to be necessary and conjectured to be sufficient for optimality. This correspondence extends the results of Veatch and Caramanis, in which necessary and sufficient conditions are found for a single machine producing two part types, and it strengthens the results of Perkins and Srikant, in which sufficient conditions are found for n part types.