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The main purpose of this thesis is to design a global supply chain network for a pharmaceutical company located in Puerto Rico, which manufactures blood sugar strips products.As a design aspect of supply chain, layered cellular manufacturing systems consist of dedicated, shared and remainder cells are considered. One of the main differences between classical cellular manufacturing systems and layered cellular manufacturing systems is, in layered cellular design, some cells may needed to be utilized by various parts of product families. Depending on the required demand and similarity in essential processes or manufacturing characteristics for each product family, products are grouped together and form a product family. If the product family assigned to one cell and just one product family utilizes that cell, the cell is a dedicated cell. Shared cells and remainder cells are employed by, two families and three or more families, respectively. In the first part of this study, a new heuristic layered-cellular manufacturing design approach is proposed and later in the second part, two mathematical models are proposed. The first one is with the objective of minimizing number of cells and cost of opening cells, and the second one is maximizing Net Present Value considering budget limitations for the whole manufacturing system. In the first step, the required number of cells are determined for a product family to meet an acceptable demand coverage (MADC) percentage. It is assumed that customer demand follows normal distribution with the established parameters mean (µ) and standard deviation (s). An attempt is made to increase the utilization of each cell by combining multiple families (thus creating shared and remainder cells) to increase the utilization of each cell as long as it is economically acceptable. As demand coverage increases, revenue also increases. However, this also increases operational costs. The expected profit is calculated based on the expected cell utilization. Cost analysis approach proposed in this study will allow us to modify cells or open new cells. The results of this heuristic approach and mathematical model are compared. Finally, simulation is employed to verify our proposed layered-cellular system based on evaluating two measurable performance factors: average flow time and work in process inventory. |
