Minimizing the Non-value Task Times: A Pickup and Delivery Problem with Two-Dimensional Bin-Packing

The current crisis that struck the automotive industry created an urgency for improvement initiatives throughout the value chain. And, although it is vital to improve the primary value chain, we should also look to improve the support services that provide for it. To this end, the current work focuses on the Manufacturing Tool Repair service, a support service in an automotive factory. This service is responsible for delivering repaired tools to the production lines and collecting the used ones. The time spent on this activity comprises 30% of the total shift time, which means that 142 min of a 480-min shift are used in this non-value-adding activity. To improve this service efficiency, we look for ways to increase the number of tools delivered in each trip, and consequently reduce the number of trips performed. For that, a mathematical model formulation for the Two-Dimensional Bin-Packing Problem was proposed. The approach was tested in 12 real-world instances and the results show that the model was able to optimally solve all within satisfying CPU time, thus allowing for real-time feedback. Also, we tested the efficiency of the model by increasing the pickup and delivery demand and the number of bins available to perform each trip.