Dimensional Accuracy on Burr-Free Blanked Products Obtained by Push-Back Blanking Method

Abstract

The push-back blanking is easy for achieving perfect burr-free blanking. This method consists of two stages, that is, the 1st stage for making the half-blanked product, and the 2nd stage for pushing it back to the original thickness. Successful blanking conditions for burr-free have been investigated already. Applying the method to the manufacturing processes of precise mechanical parts more widely, dimensional accuracy of burr-free blanked products should be known. In this research, influence of material constraint conditions on dimensional error and shear droop is investigated. As the results, it is found that the employments of material constraint at 1st stage, strong blank holder and counter punch, improve the dimensional accuracy and reduce shear droop. Dimensional improvement mainly depends on the ideal shape of half -blanked specimen obtained at 1st stage using strong blank holder and counter punch.