Effect of punch and die geometry on trimming quality of aluminium and steel autobody sheet

Tooling modifications that aim to reduce the burr height in the trimming of 6111-T4 aluminium alloy autobody sheet have been investigated. The results at zero-angle trimming show a significant influence from the punch and die geometry on the burr height. Modifications to the punch and die for trimming at 20° cutting angles have been made to increase the stress concentration at those points. While the modified punch gave slightly unfavourable results, the modified die showed some noticeable improvements in terms of burr height relative to the standard die, especially at larger clearances. Some comparisons showing the increased quality of trimming aluminium alloys at cutting angles when compared to drawing steels have also been made.