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This research was aiming to investigate cutting characteristics of Polystyrene ribbon that were cut by nail clippers. A pair of rotational-linked fixture of recent designed JIG was developed for measuring the cutting load and displacement of nail clipper arm. Nail clippers had the upper apex angle of αU = 13°, αU ' = 45° and lower apex angle of αL =20° and the lower biting edge thickness w L was chosen 0.06 and 0.25 mm. A 2-mm-width and 1-mm-thickness polystyrene ribbon was cut using the nail-clipper and the load response and the cut trace of sheared zone were investigated under the indentation velocity at V = 0.01 mm⋅s−1. A large force dropped and unstable crack was detected when using w L = 0.06 mm, while the force drop was disappeared without any large crack when w L = 0.25 mm due to the frictional restriction for fastening the work piece. While the peak line force was direct variation with tip thickness. When considered to vibration during cutting process by using AE sensor, nail clipper that have lower anvil thickness at 0.25 mm have lowest amplitude. Moreover, the cut traces were detected by microscope CCD camera.

This research was aiming to investigate cutting characteristics of Polystyrene (PS) 3 mm square bars subjected to indentation of a center bevel (blade angle of 42°) steel blade and stacked on an AL anvil (underlay). To reveal the effect of contact width of workpiece against the anvil on the sheared edge profile of workpiece, the contact width was varied from 1 mm to 40 mm during the cutting test. In this process, the cutting load response was investigated and the sheared edge profile of workpiece was observed by a microscope. To discuss the effect of the anvil width on the deformation behavior of workpiece, a finite element method (FEM) analysis with elastoplastic plain strain model was developed using a crack generation rule. Through the experiment and FEM analysis, a proportion of wedge penetration flow and crack propagation of sheared workpiece was revealed with the contact width. The peak maximum cutting force, pre-crack position and the breaking position were characterized with the contact width. When the contact width was two times or much larger than the thickness of workpiece, the wedge penetration flow form was remarkably appeared, while the crack propagation based smooth flat form was appeared when the contact width was narrower than the thickness of workpiece. A bentdown or bent-up deformation of workpiece varied with the contact width and its sign change occurred when the contact width was about two times of the thickness of workpiece. When choosing the narrower contact width than the thickness of workpiece, an asymmetric crack propagation occurred due to the misalignment of blade position against the left and right side edges of anvil.

In this work, the tensile characteristics of a 0.2-mm-thick polypropylene (PP) sheet subjected to indentation with virgin and blunt knives (apex angle, α=42◦; tip thickness, w=6 and 20 μm, respectively), were experimentally investigated. To determine the effect of mechanical condition, such as the notched depth and the profile of the root surface, on the breaking behavior of the half-cut PP specimen, the tensile testing of the half-cut specimen was carried out by varying the indentation depth and tensile velocity. By the experiments, the breakage behavior of the scored (half-cut) zone was determined by varying the indentation depth, tip thickness of the blade, and elongation rate. A kind of crazing or cracking by the blunt knife decreased the tensile resistance and burr elongation for an indentation depth larger than 0.9, whereas the work hardening by the blunt knife increased these properties for an indentation depth less than 0.8. When a blunt knife was used at a high elongation rate larger than 0.01 s-1, the half-cut zone of the PP sheet exhibited brittle fracture, i.e., the tensile resistance and burr elongation decreased.

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