The Design and Evaluation of Twisted HDPE Grass-Cutting Lines: A Performance Comparison with Commercial Nylon.

This study presents the design and performance evaluation of a custom extrusion die for producing grass-cutting lines from high-density polyethylene (HDPE) with twist angles of 0°, 15°, 30°, and 45°. The mechanical properties, cutting efficiency, and energy consumption of the HDPE lines were compared with those of commercially available nylon lines with round and square profiles. The die successfully produced twisted HDPE lines with consistent geometry. Although the HDPE lines exhibited lower tensile strength than their nylon counterparts, due to inherent material differences and residual stress from twisting, they demonstrated comparable elastic modulus values. Importantly, HDPE lines require significantly less energy during processing, offering a cost-effective and environmentally friendly alternative. Cutting tests showed that the 45° twisted HDPE line achieved cutting performance comparable to the square-profile nylon line and surpassed the round-profile variant. These results highlight the potential of HDPE as a viable, energy-efficient material for grass-cutting applications, particularly when optimized through geometric design.