Performance Evaluation of an Automatic Transfer Line with WIP Scrapping During Long Failures

Abstract

We develop a model of a failure-prone, bufferless, paced, automatic transfer line in which material flows through a number of workstations in series, receiving continuous processing along each workstation. When a workstation fails, it stops operating, and so do all the other workstations upstream of it. The quality of the material trapped in the stopped workstations deteriorates with time. If this material remains immobilized beyond a certain critical time, its quality becomes unacceptable and it must be scrapped. We develop analytical expressions for important system performance measures for two cases. In the first case, the in-process material has no memory of the quality deterioration that it experienced during previous stoppages, whereas in the second case it has. In both cases, we assume that the workstation uptimes and downtimes follow memoryless distributions. We use the analytical expressions to numerically study the effect of system parameters on system performance. To evaluate the memoryless assumption, we compare the performance of the original model to that of a modified model in which the workstation downtimes do not follow memoryless distributions. The performance of the modified model is obtained via simulation.transfer line, material scrapping, performance evaluation

Lead time distribution in unreliable production lines processing perishable products

“…The installation of a properly sized in-process buffer at a specific point of the line led to a reduction in failure impact on product quality and an increase of the system efficiency. In [9] the author focused on the production rate of asynchronous production lines in which machines are subject to failures. If the failure of a machine is long enough, the material under processing in the upstream machines must be scrapped by the system.…”

Improving the performance of manufacturing systems with continuous sampling plans

“…In this model, buffers are not considered and thus the performance regarding WIP is not calculated. The performance evaluation of bufferless production lines was also studied by Liberopoulos et al (2007), who analyzed the effects of system parameters such as failure rates on performance measures such as yield and scrap rate.…”

Integrated analysis of quality and production logistics performance in manufacturing lines

“…Furthermore, in [Bassetto and Siadat (2009)] the application of a methodology for updating the manufacturing control plan by integrating product, process and tool data within a system level perspective is proposed, related to semiconductor manufacturing. In [Liberopoulos et al (2007)] the production rate of asynchronous unbuffered production lines in which machines are subject to failures are considered. Products under processing are deteriorating items, in the sense that their quality characteristics deteriorate over time.…”