A mixed distribution system of direct and relay delivery methods based on an analogy of milk-run logistics

This paper proposes a new physical distribution model to express a mixed system of direct and relay delivery methods from the manufacturer to the shop. The direct and relay delivery methods should be selected and appropriately applied depending on the situations. However, a system with the intermediate characteristics of these two methods may be effective for some settings in practice and is proposed in this paper. This method is based on an analogy of the milk-run distribution method. Milk-run logistics is a method such that the manufacturer's trucks begin at the factory, move to suppliers, collect parts at each supplier's plant, and return to the factory instead of the usual distribution by suppliers. Though milk-run logistics is an effective method as an inbound logistics system, this paper identifies how an effective distribution system can be constructed for outbound logistics. A basic system model is shown for a distribution model with three layers, including an analysis of the model by Z transform. From the numerical examples, the effectiveness of the proposal is clarified. In the proposed system, the variances of inventories in the relay distribution center and shop can be reduced.