Design and experimental optimization of a bio-inspired beak-shaped blade for superior natural rubber tapping performance

The double-edged V-shaped knife has been used in rubber tapping for a century, but its cutting mechanism is limited. Current research predominantly focuses on optimizing this traditional tool, with little exploration of potentially more efficient cutting methods or novel blade designs. This study designed three rotary blades (BEB-L, BEB-U, and TBB) by applying the biomechanical principles of a woodpecker’s beak. A full factorial experiment was conducted using simulations of cutting perpendicular to wood fibers to systematically analyze cutting behavior under different parameter combinations. Based on these results, an optimization experiment was performed with the selected optimal parameter levels. The best-performing biomimetic blade was then compared with the conventional V-shaped tool in actual rubber tapping trials. Cutting performance was evaluated based on peak cutting force and energy consumption. The cut surface quality was quantitatively assessed using laser scanning microscopy (LSM) to obtain surface roughness parameters (Sa, Sz, Str, Sdr). Element deposition on the blade edge was examined using energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). Results demonstrated that the BEB-U blade outperformed the BEB-L and TBB designs. The optimal parameters were a 3-mm thick BEB-U blade, a cutting speed of 20 mm/s, and a rotational speed of 1500 r/min, under which it exhibited superior cutting performance and practical feasibility. This study provides a theoretical basis and practical reference for developing new rubber tapping tools.