BATCH-SIZING AND BUFFER STOCK MODELS CONSIDERING CHANGES IN THE PRELIMINARY ORDER

• Main Author: DARMA WANGSA (NIM : 23410001); Dosen Pembimbing : Prof. Dr. Ir. Bermawi P. Iskandar, IVAN
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/16128
• Institution: Institut Teknologi Bandung

Scheduling changes on the production floor are common in practice to meet the consumer demand and these cause the nervousness. The nervousness in turn will result in increased costs and reduced service level. This research deals with production batch size and buffer stock taking into account changes in a preliminary order. Demand (as the preliminary order) for the coming week (five days) varies from day to day and is received on Friday. Change in the demand for a given day is announced one day before and this is viewed as it occurs randomly. <br /> <br /> <br /> This research considers a two echelon supply chain system with a single supplier and single manufacturer. Two models have been developed – i.e. under transactional relationship and supplier-owned inventory contract relationship. A mathematical model is formulated for each and the objective function is the total inventory cost. The decision variables are the period of production run, production batch size, and buffer stock. Heuristic methods used are Silver-Meal (SM) and Least Unit Cost (LUC) to obtain solution for each model. Algoritm is developed to assist in finding a solution. This study also considers the backorder and production capacity according to the real condition. <br /> <br /> <br /> Numerical examples are given to demonstrate the performance of the models. From the numerical results, it appears that coefficient variation (CV) of the demand affects the results obtained using method of SM and LUC. It is concluded that the proposed models with larger the CV value provides better savings than those of Pujawan and Silver (2008), and vice versa.