Cross-docking Operation Scheduling: Truck Arrivals, Shop-Floor Activities and Truck Departures

Cross-docking is a relatively new logistic strategy which seeks to make economies in transportation, decrease lead time and reduce inventory. The main principle is to unload, sort, consolidate and transfer delivered packages from inbound trucks to outbound trucks, with a minimum of storage or treatment in between. Two key issues associated to this field are the truck scheduling and the shop-floor operation scheduling. We propose a mixed integer linear programming model to schedule truck arrivals, shop-floor activities and truck departures. The cross-dock configuration we study is based on an industrial case on the automotive industry. In particular, a repack operation and two temporary storage zones are considered. The objective is to minimize internal operation cost (penalty related to extra capacity needs) and outbound transportation cost (number of trucks). The model is implemented and tested in CPLEX with small size instances, based on industrial data. The proposed model could be easily adapted to a variety of cross-dock configurations, in terms of internal capacity and cost distribution.