Some structural properties for the just-in-time level schedule problem

Just-in-time (JIT) is a pull concept applied mainly in repetitive manufacturing systems, and it is characterized by a scenario where only the required units are produced in the required quantities at the required times. It particularly aims at eliminating wastes associated with inventories in the system. A level schedule is desirable for a JIT assembly system, as it serves as an approximation for all forms of smoothing. The minsum formulation of the assembly line level schedule problem is one of those that has been mainly used in the literature. Using this formulation as a base, we develop some useful structural properties for the problem. Among other things, it is shown that a level schedule would tend to be more difficult to achieve for products (models) with comparatively fewer units in the products composition structure.