Friction wear test evaluation for assembly tool

Conventional method to define the useful tool life is by punching the actual molded units in trim and form (TNF) machine. Throughout the punch intervals, the punched leadframes were sent for inspection for any side burr observed at the leads. This process might take several days or weeks in order to reach the end of punch tool lifespan. It is quite a manual and time consuming task, if it involves several types of punch tool to be examined. Beside that, this method does not capture the wear rate of the punch tool. This paper demonstrates the friction wear test of punch tool to obtain the wear rate using Bruker Tribolab UMT tester, which is equipped with reciprocating drive. The punch tool is hold stationary at the carriage (z axis), and rub against the dummy molded unit, which oscillated by the reciprocating drive. The volume loss of the punch tool is plotted against the number of reciprocating cycles to determine the wear rate. The wear mode of the punch tool is investigated at end of the test. From the results of this study, it is shown that the punch tool's volume wear vs the reciprocating cycles fit well with the linear line. The wear rate of punch tool is calculated from the slope of the linear line.