A Multi-site PlanningApproach for theTFT-LCD Production Chain 193

Due to the increase of a variety of demands from downstream customers, the enterprises are necessary to expand more capacity of their factories by way of adding more plants or outsourcing. Many enterprises encounter great difficulties in production planning because manufacturing environments have changed from traditional single-plant to current multi-plants. Therefore, the company may possess many manufacturing plants located in different places geographically, and the production planners will face the demand allocation problem in the multi-site environment. The decisions may include the manufacturing routings of demand products and production amounts among multi-plants. As a result of these motivations above, we propose a hierarchical framework of the multi-site production planning. It results in a multi-site production allocation planning and then in single-plant master production scheduling and shop-floor operations scheduling like traditional manufacturing planning and control (MPC) tasks. This paper focuses on the multi-site production planning problem. A linear programming (LP) mathematical model is developed to solve this problem. In addition, we also take a numerical example from a real TFT-LCD (Thin Film Transistor-Liquid Crystal Display) manufacturer in Taiwan to illustrate our hierarchical multi-site planning approach and solution model.