Design and implementation of internal logistics system in a vehicle mounted crane manufacturing company

Vehicle Routing Problem (VRP), one of the most important internal logistics problems of the manufacturing sector today, aims to determine the route with the minimum distance for transportation vehicles that meet the demands of the customers. In line with this goal, many studies are being conducted on internal logistics problems, and solution methods are being developed. Within the scope of this thesis, literature review on internal logistics applications has been conducted, and the definition of an internal logistics transportation problem in a real-life crane manufacturing company that can be evaluated within the scope of Stacker Crane Problem has been made. In order to do the solving of the problem, a mathematical model has been created by adding inequalities that provide real-life conditions. At this model, there are basic restrictions in the MTSP, such as visiting each customer only once, the trajectory of the routes starting and ending at the depot and the nodes that each vehicle can go to. In order to provide experimental studies, the 15-days work process in the company was followed, and the work data of three transportation vehicles were obtained. The distances between the nodes of the company and the weights and pallet needs data were obtained. In line with the data received, the optimized routing way of three transport vehicles was carried out using the GAMS/CPLEX package program. As a result of the solution of the mathematical model made by applying it to the company, optimal results were achieved compared to the current situation. According to the results of the study, significant improvements have been made in the internal logistics process of the crane manufacturing company, and operational efficiency has been achieved. As a result of optimization studies carried out using 15-days real internal logistics data, the increasing of the 55.72 % efficiency was achieved in internal logistics operations. Comparisons between the current situation and the optimization study have revealed important information for the improvement of internal logistics processes. This thesis contributes to significant improvements in the internal logistics processes of the company where the application is made by showing the strategic importance of lean production and internal logistics in the crane manufacturing sector.