'Just-in-time' production of large assemblies

The problem of scheduling operations in a manufacturing facility that produces large assemblies is considered. Given the due dates of the end items, the objective is to determine a schedule that minimizes the cumulative production lead time. The lot sizes of the end items are considered known and 'just-in-time' (JIT) production is assumed. The scheduling problem within such an environment has been formulated and is NP-hard. Its similarities to and differences from the well studied resource-constrained project scheduling problem have been established. An efficient heuristic is developed that uses the precedence network of operations to prioritize execution of those operations that belong to a dynamically computed critical path. The effectiveness of the proposed heuristic is assessed in terms of cumulative lead-time and work-in-process inventory (WIP) costs.