New valve needle cylinder for hot runner system stability improvement
September 30 10:06:47, 2025
Ben Somme, Germany, October 2005 – In the field of long glass fiber injection molding, product stability is directly influenced by the length of the fibers used. The longer the fiber, the more stable the structure becomes, with each additional millimeter contributing to improved mechanical properties. To address this need, Synventive Molding Germany, based in Bentheim, introduced an innovative valve needle cylinder for its hot runner system. This new design features a significantly larger stroke and an optimized flow path, allowing better retention of long glass fibers during the injection process.
The development was driven by the growing demand for longer fibers in applications that require enhanced strength, impact resistance, and dimensional stability. With the increasing use of long fibers by filament yarn blending companies, manufacturers are looking for solutions that preserve fiber integrity throughout the molding cycle. The metering device plays a critical role in minimizing fiber breakage, and the gate remains a key stress point for both the hot runner system and the raw materials.
To reduce stress and shear forces, the new system incorporates larger cross-sections, rounded corners, and runners that do not interfere with the valve needle movement. These improvements help protect the fiber material and extend the service life of valve pins and hot nozzles. The new Synventive HYC 4018 and PNC 7518 (Hydraulic/Pneumatic Drive) models offer a range of benefits, including greater fiber retention, reduced shrinkage, less deformation, and improved flow characteristics.
Additionally, the reduction in skin thickness not only makes parts lighter but also shortens cooling times, boosting overall productivity. The new valve needle cylinder also includes features such as height-adjustable valve stems, lockable and externally adjustable valve stems, and a patented needle bushing with efficient cooling technology. These enhancements make it ideal for industries such as automotive, household appliances, and electrical installations. By extending fiber length per millimeter, Synventive provides injection molders with a competitive edge through improved part performance and manufacturing efficiency.