Abstract
In the RGB process of color filter production, different products can be processed on the same parallel machines, and each product has at least three visits to the parallel machines. This thesis focuses on the production scheduling of the RGB process, and the objective is to fulfill the demand of later production stage in time. After observing the RGB process, this study considers the following three factors: (1) the demand rates of products are time-varying; (2) different operations have sequence dependent setup time; (3) products are manufactured by lots. This thesis uses a two-stage approach to solve the production scheduling problem. In the first stage, the EOQ model is used to determine the proper lot size. A production lot can be treated as a job in the parallel machines scheduling problem. In the second stage, the apparent tardiness cost with setups (ATCS) dispatching rule is applied to obtain the initial schedule, and then a search algorithm is used to improve the initial schedule calculated by ATCS dispatching rule. We compare three search algorithms in this thesis. They are Simulated Annealing, Tabu Search and Memetic Algorithm. In the computation experiment, several factors are used to investigate their influences on the total tardiness. Four factors affect the result significantly. In the scheduling environment, shorter planning horizon, more parallel machines and less product types can reduce the total tardiness. In the search algorithms, the Tabu Search outperforms the others. Keywords: RGB process, production scheduling, reentry, economic lot size, search algorithms.