Doctor of Philosophy (PhD), Ohio University, 2017, Mechanical and Systems Engineering (Engineering and Technology)

Demand uncertainty has been an important obstacle in production systems and supply chains in recent decades. This uncertainty in demand has stimulated many researchers and practitioners to find new ways--such as combining Make to Stock (MTS) and Make to Order (MTO) manufacturing systems--to handle the uncertainty problem. In this research, applying the hybrid MTS/MTO system is developed in three different manufacturing frameworks. The first framework considers a production line, which produces semi-finished products based on a Make To Stock (MTS) strategy until a specific process is finished, and operates based on a Make To Order (MTO) strategy after this process. Two scenarios are studied in the first model: 1- In the first Scenario, the production line applies the MTO strategy after the OPP, which leads to an idleness cost when there is no order in the system. 2- In the second Scenario, the production line either applies the MTO strategy or the MTS strategy after the OPP, based on the presence of an order for semi-finished products in the line. This second scenario comprises the holding cost of completed products on MTS strategy, but does not have an idle cost. The second framework considers the demand uncertainties in two consecutive echelons of a supply chain--unlike most of the field research--which has only focused on the final customer's demand uncertainty. In order to decrease the operating costs of a manufacturer, a model is proposed to use hybrid manufacturing in two different levels of a supply chain with two echelons of manufacturers. The output of the presented model is the quantity of semi-finished products ordered by the decoupling point upstream manufacturer. The third problem studies a multi-product, two-echelon supply chain within a newsvendor framework, in which semi-finished products are produced by a supplier and customized according to specific customer orders. The focus of this paper is to investigate a situation where the manufacture (open full item for complete abstract)

Committee: Gary Weckman (Advisor); William Young (Committee Member); Dale Masel (Committee Member); Benjamin Sperry (Committee Member); Yong Wang (Committee Member) Subjects: Business Costs; Industrial Engineering; Management; Marketing

Master of Science (MS), Ohio University, 2006, Industrial and Manufacturing Systems Engineering (Engineering)

A comparison between two cellular manufacturing systems namely; connected and disconnected systems have been studied in order to evaluate the performance of each system with respect to certain performance criteria. Two cases have been considered namely: Make to Order and Make to Stock environment. In the make to order case, a sub case with different process routings for each family has been considered. Simulation models for each of the systems and each of the cases were developed in ARENA 7.0 simulation software. The data used to model each of these systems were obtained from a medical products manufacturer for a maximum period of nineteen months. The models were run 24 hours a day which basically represented 3 shifts round the clock. It was expected that the disconnected system which had a higher flexibility would perform better in both cases. The results obtained indicate that for case 1, connected system performed better than disconnected system in most of the comparisons made. Also, an increase in routing flexibility resulted in lower flowtimes and work in process depending on the cellular design of the system. In case 2 for the make to stock environment, the disconnected system performed better than the connected system with lower finished goods inventory and lower overall inventory.

Committee: Gürsel Süer (Advisor) Subjects: Engineering, Industrial