Effect of Underlay Stiffness on Cutting Profile of Polycarbonate Sheet during Wedge Indentation Process

This paper reports on the cutting characteristics of a polycarbonate (PC) sheet stacked on a flexible underlay by a wedge indentation. In order to investigate the effect of underlay stiffness on sheared profile of PC sheet, the stiffness ratio k(r) in the thickness direction was varied. Indentation of a 42 degrees center bevel blade into a 0.5 mm thickness PC sheet that was stacked on the flexible underlay was carried out experimentally and numerically. Deformation profile of wedged PC sheet was observed by a CCD camera in order to reveal the effect of underlay on the cutting performance of the PC sheet. On the experimental works, it was found that the underlay mechanical properties affected the cutting load response and deformation features of the PC sheet. To discuss the effect of underlay stiffness on the deformation profile of the PC sheet, a finite element method (FEM) analysis with elasto-plastic model was conducted. Through the experiment and FEM simulation, it was revealed that the deformation profile of wedged PC sheet was remarkably related to the bent-up angle of the PC sheet, which was mainly caused by sinking and lateral elongation of the underlay. Moreover, in order to obtain a smart profile of the PC sheet, the stiffness ratio kr must be chosen in a suitable range.