A design framework based on the non-planar partitioned flow path for discrete material flow systems
The design of material handling network has a critical impact on the overall performance of a manufacturing system. The challenge in a material handling flow path design is to come up with a design that gives an efficient performance in terms of throughput and requires a controller with low level of complexity. Although complicated configurations like bidirectional conventional systems can perform well, they require a sophisticated expensive controller that can allow them to perform with full capacity. On the other side, less complex configurations like unidirectional single loop patterns or tandem configurations require much simpler and cheaper supervisory controller and operational strategies; however, they are generally inferior to more complex systems in terms of performance. The non-planar partitioned flow path (NPFP) has been introduced. The basic concept of this approach is to partition the system into material handling zones defined by sets of machines or pickup/delivery points. Each zone is operated in bidirectional mode and served by one material handling device to reduce the control complexity. Flow paths from different zones can be overlapped or crossover. A transfer buffer must be determined for each zone serving as input and output point where the device can pick up outgoing loads or drop off incoming loads of that zone. A design r framework for the NPFP was introduced by implementing mathematical programming and simulation models. Simulation experiments were conducted for two test facilities, Facility A with 9 machines and Facility B with 20 machines, in order to compare the performance of NPFP systems with unidirectional conventional systems. According to simulation results, NPFP systems reduce the time in system up to 27% for Facility A and 85% for Facility B. Vehicle utilization of NPFP systems are also significantly lower than that of conventional systems. The simulation also suggested that the benefits of applying a NPFP system be more appealing in large size facilities.^
Major Professor: Jose M. A. Tanchoco, Purdue University.