Reliability analysis for machine working and causes of defective machines : A case study of an autoparts manufacturing factory

Abstract

This research proposes reliability analysis in order to find the probability that a machine will work properly, the failure rates of a machine, and the factors related to the failure rates. The data were collected from 8 types of machines in an autoparts manufacturing factory. They consist of the times measured from the first day of the study until the machine produces defective product, workers and production steps. The study duration is 90 days. The results show that the probability that the machine type 4 will work properly more than days is 0.40, machine type 5 more than 68 days is 0.32, machine type 6 more than 72 days is 0.31, machine type 8 more than 85 days is 0.26, machine type 9 more than 109 days is 0.80, machine type 10 at more than 52 days is 0.38, machine type 11 more than 71 days is 0.32, and the probability that the machine type 12 will work properly more than 85 days is 0.26. The failure rate of the machine type 4 at day 51 is 6.61, machine type 5 at day 68 is 1.61, machine type 6 at day 72 is 0.77, machine type 8 at day 85 is 1.26, machine type 9 at day 109 is 1.31, machine type 10 at day 52 is 0.92, machine type 11 at day 71 is 1.24, and the failure rate of the machine type 12 at day 85 is 2.15. The factors influencing on the failure rates are worker group 2 and production step 3 at the significance of 0.05.