While manufacturing high‑tenacity PP FDY multifilament for geotextiles, lifting slings and ropes, many chemical‑fiber plants suffer obvious yarn tenacity dispersion. With same chips and production line, tenacity varies among different bobbins and triggers intermittent yarn breakage during downstream weaving. Technicians often adjust chip formula and manifold temperature with limited improvement. Defects frequently stem from roller‑speed synchronization, temperature‑control accuracy and transmission stability of high‑tenacity polypropylene yarn stretching machine.

To reach tenacity above 7g/d, high‑strength polypropylene filament relies heavily on stable speed‑difference and thermal condition of multi‑stage drawing. Asynchronous roller speed or local temperature deviation causes inconsistent actual draw ratio among yarn bundles and insufficient molecular orientation, resulting in tenacity fluctuation. Clearance fluctuation of transmission system brings tension offset among spindles under high‑speed operation, producing uneven bobbins even with qualified raw materials. Simply raising draw ratio may lead to over‑stretched filaments and hidden brittle‑breakage risk.

For equipment procurement, theoretical maximum spinning speed and output are not the only criteria. Multi‑roller synchronization and independent temperature‑control performance deserve high priority. Modular design facilitates maintenance and prevents parameter drift during long‑time operation.

As a national high‑tech enterprise, Jiangxi Donghua machinery Co., LTD develops DHP419 series polypropylene yarn stretching machine with integrated automatic spinning control system and multi‑zone independent drawing configuration for high roller‑speed synchronization. Final yarn tenacity can exceed 7g/d for industrial PP filament used in geotextile, lifting sling and rope sectors. Cooperating with Donghua University, National University of Defense Technology and other institutes, the machine features compact footprint. Custom process solutions are offered according to target denier and capacity requirements, helping fiber mills reduce tenacity dispersion and improve bobbin batch consistency.

Against the upgrading trend of industrial polypropylene filament, control accuracy of drawing system acts as core specification for polypropylene yarn stretching machine.