Thayer, S.B. (1986, ASQC) Colorado State University, Fort Collins, CO
The paper describes three steps used successfully by a manufacturer of an electro-mechanical product to design reliability into a new product. Step one, was an estimate of the reliability of each subsystem of the existing design. This analysis was used to identify those low reliability subsystems that should be designed out of the next generation. Step two, was the use of Duane plots during design verification test to plot the rate of reliability growth. The log-log plots of cumulative mean time between failures saw a steady rate of growth which allowed prediction of the mean time between failures for the product at customer release which was two years in the future. Step three, was the plotting on Weibull probability paper of the results of the production verification test program. The Weibull plots were useful in predicting the mean time between failures for a product incorporating all engineering changes. The Weibull plots also allowed the identification of failures due to manufacturing errors, wearout, or chance.