Temporal Capacity Constraints and Supply Chain Balancing

This chapter discusses leveling off (smoothing out) demand in mixed-model, pull supply chains. These chains respond to customer demand by setting forecast-based demands for each model produced, and pulling supplies required for model production whenever they are needed. To level off and synchronize these supply chains, it is crucial to design model delivery sequence for given demands for models. Two main goals shape this sequence. The external, that is meeting the model demands, and, the internal, that is satisfying the chain temporal capacity constraints. These constraints may render a model delivery sequence difficult to implement through the pull mechanism of the chain just-in-time material flow for the sequence may temporarily impose too much strain on supplier's resources by setting too high a temporary delivery rate for their supplies.

The chapter addresses the temporal supplier capacity constraints. It presents in Sect. 9.7 a framework for a mixed-model, pull supply chain, and proposes using the model of temporal capacity constraints based on the car sequencing problem to level off demand in the chain. It claims that this model of temporal capacity constraints though typically used to better balance the workload of mixed-model assembly lines may serve a more important and general goal of leveling off demand in the entire supply chain. We assume in particular that supplier s is a subject to a capacity constraint in the form p_s : q_s, which means that at most p_s models of the model delivery sequence S in each consecutive sequence of q_s models of S may need options supplied by s. A digression: it seems natural here and later in the chapter to use the small letter s to denote a supplier, we hope this notation will not be confused with the notation that uses the letter to denote sequences in other chapters of the book.