Finetuning a single-blade sonic paper-cutter as an energy-saving sharpening instrument

Constant usage and exposure to harsh environments results in a blade to become blunt. Two matching circuits were developed to improve the energy efficiency of an ultrasonic single-blade paper-cutting tool, whilst enhancing the sharpness of the blade. The unmatched ultrasonic knife had a measured magnitude of −0.3 dB and a resonance frequency of 251 kHz. The incorporation of a matching circuit significantly improved the magnitude indicating greater power transfer and consequently energy efficiency. The sharpening effect of ultrasound was qualitatively and quantitatively investigated, where both yielded a less tortuous cut under sonication in comparison to the unsonicated case. The addition of a matching circuit further improved the cutting efficiency. At an operating voltage of 10Vpeak, the cut made by the ultrasonic knife with a matching circuit was less tortuous than even an industrially cut edge, with a linearity of 61–63 % compared to 59 %, respectively.