Prediction of punch life in notching process for automatic transmission retainer considering fatigue and wear

In notching process, predicting punch replacement period is very important. The retainer made of thick steel plate is one of the important components of the automatic transmission. The transmission retainer is produced through a shearing process, such as a piercing or notching process. In this process, very high stress occurs in the punch because of high strength and thickness of steel plate. Therefore, punch life is very short. In this study, the fatigue and wear life of the punch in notching process is predicted using numerical analysis. An experiment was conducted to verify the effectiveness of the result of numerical analysis for predicting the punch life. From the experiment the fatigue failure of the punch and the wear depth in notching process are measured. From the results the wear and fatigue life predicted through numerical analysis agree well with the experimental results.