Abstract

Reliability function, R(t), is defined as the probability that the system will not fail during the stated period of time under a given operating conditions. In production process, attaining reliability as a function of time is a common task but in multi-stage services, it is not straightforward due to intricacy of gathering data. Through the present work, we have addressed a systematic method for measuring multi-stage service reliability function using failure rate analysis beside a systematic six sigma approach to improve total system reliability. The proposed methodology furthermore could help practitioners to integrate six sigma metrics with the reliability function and the way to measure existing reliability situation based on sigma level. The proposed method is applied in a given multi-stage central repairing shop for an automobile producer which promotes 86% in total system reliability beside 58% improvement in the sigma level.

Key words: Service reliability, six sigma, failure rate, multi-stage processes, sigma level.