Time Parameter Estimation Using Statistical Distribution of Weibull to Improve Reliability

Environmental stress screening program, which is used in development phase of manufacturing, causes decrease or even elimination of hidden faults of products before competency tests. This can lead to significant improvement in product reliability and decrease in maintenance costs. During environmental stress screening test, the product is exposed to a certain environmental conditions such as temperature, humidity and vibration in a certain level for some amount of times. The exposure time is a very important parameter that should be determined accurately using statistical methods. The aim of this paper is to calculate the optimal exposure time for an environmental stress screening process using Weibull distribution which has wide applications in reliability analysis. A case study of electronic sets is then applied to illustrate the process step by step. After determination of Weibull parameters, obtained results and charts are used to calculate the time parameter of screening test for the components.

Keywords:

Environmental stress screening , Weibull distribution , Reliability , Exposure time , Competency test