Disposal of hot runner mold
Part of the material leakage is not due to poor system design, but due to failure to operate according to design parameters. Leakage usually occurs at the seal between the nozzle and the manifold. According to the general hot runner design specifications, the hot nozzle has a rigid edge to ensure that the height of the hot nozzle assembly is smaller than the actual groove depth on the hot runner plate. This difference in size (commonly referred to as the cold gap) is designed to avoid thermal expansion that can cause component damage when the system is at operating temperature.
1. The back of the hot nozzle is fixed on the manifold; the high temperature bolt that fixes the hot nozzle to the manifold can prevent leakage under cooling conditions. This system still requires cold clearance, because rigid edges require some expansion space at normal temperature. Although this method can actively prevent leakage from the nozzle to the manifold, it cannot prevent the thermal expansion of the component under overheating conditions.
2, the hot nozzle fixed to the manifold with bolts moves with the manifold together. This design has a minimum length requirement for the nozzle and a limitation on the cavity spacing. It is an economical and effective way to prevent leakage between the hot nozzle and the manifold. It is suitable for systems with a small number of cavities.
3. The edge of the hot nozzle is designed with elasticity instead of rigidity. The elastic edge provides preload under cooling conditions and prevents system damage. If accidentally overheated, it can also absorb thermal expansion, expanding the operating range to ± 110 ° C.