The design assignment of connecting portions on a paperboard is important in order to stabilize the transport of the paperboard during die cutting. A mechanical estimation of various deformations of connecting portions is desired to predict an allowable assignment of connecting portions. The main purpose of this study is to reveal the elongation properties of the connecting portion of a paperboard with respect to several primary parameters such as nick width and crushed blade tip thickness. The result shows that there is a lower bound width of the connecting portion; the tensile strength of the connecting portion strongly depends on the cutting direction and grain (machine) direction of the paperboard. It is also clarified that the presence of string like dust affects the tensile strength of the connecting portion and that increasing blade tip thickness reduces the tensile strength of the connecting portion.

This paper describes for breaking behaviors on the surface layer of a white-coated paperboard during indentation of a center bevel blade. Cutting load response of the paperboard was measured regarding the indentation depth of the blade and the deformation flow in a side view of the paperboard was observed by a CCD camera in order to investigate the effect of blade tip angle on the surface failures of the paperboard. The surface breaking strength of paperboard was analyzed by using Finite Element Method (FEM). Through the experiment and FEM simulation, the followings were revealed. 1) There is a certain critical value of tip angle C at which an inflection load response disappears and also the surface failures are restricted. 2) When the tip angle is less than the C, there is an inflection point as the surface-layer breaking and its surface breaking point was strongly related to the maximum principal stress on the surface. 3) After the surface breaking, the deformation flow and its cutting resistance are strongly affected by the de-laminated and the raised-up of the inner-layer.

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 α C and the tip thickness w C 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.

In this paper, we describe a pushing shear process carried out on a white-coated paperboard. The cutting load response of a 42°center bevel blade on the paperboard was measured by varying the mechanical conditions of a rubber fixture. An early-stage deformation of the paperboard was numerically analyzed with the orthotropic elastic model, and the stress distribution in the surface layer of the paperboard was discussed with respect to the rubber fixture effect. From the experiment and numerical simulation，the following results were obtained. (1) The load of inflection point f C1 which corresponds to the surface layer breaking，decreases by 10-20% as a result of the mounting of a rubber fixture on a die set，while the load of peaked point f C2 ，during the final breaking，increases by 0-10% as a result of the mounting of the rubber fixture，for a specified condition of rubber fixture mounting. (2) The maximum principle stress (tensile) markedly increases at the surface layer near the blade tip as a result of considering the rubber fixture，at the early stage of blade indention into the paperboard. (3) The maximum principle stress markedly decreases in the surface layer, which is in 2-4 times the paperboard thickness from the blade tip，at the early stage.