Bottlenecks in production systems: A systems approach.

In this work, the notion of bottlenecks in production systems is analyzed. Specifically, a machine is defined as the bottleneck if the sensitivity of the system's performance index to this machine's production rate in isolation is the largest. Although appealing from the systems point of view, this definition suffers a deficiency due to the fact that the sensitivities involved cannot be either measured on-line or efficiently calculated off-line. To avoid this, the work develops a method based on indirect but real-time data. From this point of view, the main result of the work is as follows: The bottleneck machine in serial production lines and assembly systems can be identified by analyzing relationships between the so-called manufacturing blockage and manufacturing starvation of each machine. This leads to a simple rule for bottleneck identification. The rule requires neither the calculation of the production rate sensitivities nor the production rate itself. When the probabilities of manufacturing blockages and starvations are not available from on-line measurements, the work presents their analytical estimates which, under certain conditions, can be used for bottleneck identification. In addition, two case studies, utilizing the results obtained at an automotive component plant, are described.PhDElectrical Engineering: SystemsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/105108/1/9635547.pdfDescription of 9635547.pdf : Restricted to UM users only