Scheduling model for hybrid production type in the process industries

Production scheduling has an important effect on the effectiveness of production activities. In production scheduling, characteristics of the production process to be scheduled must be concerned. In this study lot sizing and scheduling problem in the cement milling process, a sub-process of cement manufacturing that are taken place under the process industries was analyzed. Eventhough there has been many studies and successful models developed in the scheduling field so far, in the literature they have received some criticism for their practical applications. The aim of this thesis is to contribute to the existing literature by developing a practically tested lot sizing and scheduling model that minimizes total of production, set-up, inventory holding, raw material and electricity costs. In line with this purpose in this study a GLSP based mathematical model considering the industry specific characteristics was developed. To improve the practical applicability of this main model, besides industry specific characteristics, demand forecasting and safety stocks that are cyclically calculated depending on the changing demand conditions were considered in the scheduling process. In addition to this main model, a capacity control model aiming to minimize lost sales was used. The main GLSP based model was run cyclically during 2014 with real data and performance of this model was compared with the firm's real production performance for this year.