Precision punching of 5052 aluminum alloy sheets

In the shearing aluminum sheets, such as blanking and punching, aluminum whiskers and a large amount of powders are generated on the cutting surfaces, in and around the die respectively. This unwanted loss of material may cause deterioration of the dimensional accuracy of products and a decrease in working efficiency, which are considered as problems in production sites. In this study, we observed the condition of the cutting surfaces upon shearing deformation and clarified three causes of material losses. Next, we proposed the method of precision punching, which enables us significantly to suppress the generation of whiskers and powder simultaneously. Precision punching is an improved method of reciprocating blanking and is a type of burr-free blanking. Specifically, a workpiece is given to a small penetration that will not be developed into a crack, using a half blanking punch with an edge angle larger than 90. The workpiece is then punched from the opposite direction using a punch with an edge angle of 90. The experiment clearly seen that this method using a rectangular punching die can perform cutting surface without whiskers, which the amount of powder generated in and around the die can also be significantly reduced.