In this paper, we gives a describe of the pushing shear process on a kraft paperboard. The cutting line force of a center bevel blade on the kraft paperboard was measured using a load cell and its cutting deformation was observed using a CCD camera to reveal the basic effects of the tip angle and tip thickness of the blade on the surface failures of the kraft paperboard. A deformation flow in the side view of the kraft paperboard was observed with respect to the indentation depth of the blade by varying the tip angle and tip thickness of the blade. From the experiment, the following results were obtained. 1) There are certain critical values of the tip angle αC and the tip thickness wC at which the inflection load response disappears and also the surface failures are restricted. 2) After the time when the surface layer of the kraft paperboard is cut off, lateral shear flow occurs in an in-plane layer of a laminated structure. The deformation flow and its resistance are strongly affected by the delamination and raised upper layer.
