Multi-level Lot-streaming Production Planning with the Objective of Workload Balancing

This paper addresses a tactical production planning problem we encountered in a factory producing high-end equipment. Various realistic characteristics in this factory such as make-to-order, multi-level product structure, lot streaming are considered. The objective is to determine the item production quantity of each order at each time period so that the workload of each shop floor during the planning horizon is as balanced as possible. We propose an integer quadratic programming model to formulate this problem. A hybrid variable neighborhood search algorithm with a local search method is proposed to solve this problem. Numerical results show that the proposed algorithm could solve the industrialsize problems effectively and efficiently in a reasonable time.