This research determines time optimal routes for loading and picking pallets that can be stacked on top of each other during transport in a manual warehouse that only contains full pallets and utilizes single deep storage. This research was motivated by the fact that we are seeing this situation on an ever increasing basis, particularly in warehouses that supply parts to automotive assembly. In practice, forklift drivers have developed strategies to take advantage of this opportunity but to our knowledge there is no literature that addresses this problem rigorously. The important features of this work are that a time based mathematical model is required because the time spent stacking and unstacking pallets can be significant and a modeling approach to including stacking had to be developed. The basic models are included here with examples and insights into future work required for applicability to a wider range of users.
Progress in Material Handling Research: 2010
Hassan, Ahmed and Ferrell, Bill, "Forklift Routing in Warehouses Using Dual-Commands and Stackable Pallets" (2010). 11th IMHRC Proceedings (Milwaukee, Wisconsin. USA – 2010). 3.