Effect of Excited Duration on Cutting Characteristics of Polycarbonate Sheet Subjected to Center-Bevelled Blade Indentation Excited by Ultrasonic Wave

This paper describes the cutting process of a 0.5 mm thickness polycarbonate (PC) worksheet stacked on another 0.5 mm thickness PC underlay by an adhesive tape layer. As the first investigation, the cutting line force of the two-line blade (90/30deg.) on the laminated PC sheet was measured with a load cell and the sheared profile of the worksheet was observed by a CCD camera in order to reveal the effect of the time delay of the ultrasonic blade excitation on the deformation flow of the worksheet. The profile parameters such as the inclination angle, elevation angle and necked height of sheared section were observed with respect to the blade excitation patterns by varying the delayed time. Secondarily, in order to investigate the effect of the excitation-duty rate on the profile parameters of the sheared zone, two kinds of ultrasonic-excitement patterns were applied to the laminated PC sheet by varying the duty rate. Through the two experiments, it was revealed that both, the positioning control in the case of the time delay and the power density control in the case of the duty ratio were superior for varying the profile parameters of sheared zone.