On the Shearing Process of Ductile Sheet Metals : 1st Report: Experiment on the "Scissors Type" Shear

Abstract

Recently, it is increasingly required to produce mechanical components by a simple blanking so accurately that the components blanked off can be fitted without any further finishing process. So, an observation of the phenomenon of material parting has become of prime importance in order to know about the result of surface formation in the shearing operation. However, in a shearing process the metal undergoes an unsteady deformation in a very limited zone. Experimental difficulty in practice arises, and an analysis consistent with both deformation and stress does not seem to have been reported. In this research, for the sake of simplicity of its geometry, the deformation in the "scissors type shear" is observed and investigated in detail. It has been clarified that the advancement of the tool can be made by causing the rigid body rotation of the material as a whole, the relative shift and the indentation. This paper refers to the possibility of a new interpretation of the shearing performance in general according to percentage of these component displacements. In a blanking of sheet metals, the material behaves under a more constrained state than in the "scissors type" shear and it is considered that a change in the proportion of these component displacements depends on the severity of constraints encountered in the process.