A Basic Period Approach for Solving the Economic Lot and Delivery Scheduling in Flexible Flow Lines

In this paper, the problem of lot sizing, scheduling and delivery of several items in a two-stage supply chain over a finite planning horizon is studied. Single supplier via a flexible flow line production system (FFL), produces several items and delivers them directly to an assembly facility. Based on basic period (BP) strategy, a new mixed zero-one nonlinear programming model has been developed with the objective of minimizing the average setup, inventory-holding and delivery costs per unit time in the supply chain without any stock-out. The problem is very complex and it can not be optimaly solved, especially in real-sized problems. So, an efficient hybrid genetic algorithm (HGA) has been proposed based on applying, the most applied BP approach i.e. power-of-two policy. Based on some problem instances, the solution quality of the algorithm has been evaluated and also compared with the common cycle approach. Numerical experiments demonstrate the effectiveness of the proposed HGA.