Runner systems

The runner system is a manifold for distribution of thermoplastic melt from the machine nozzle to the cavities. The sprue bushing and runners should be as short as possible to ensure limited pressure losses in the mold.  Properly sizing a runner to a given part and mold design has a tremendous pay-off. To summarize a runner system that has been designed correctly will: Deliver melt to the cavities Balance filling of multiple cavities Balance filling of multi-gate cavities Minimize scrap Eject easily Maximize efficiency in energy consumption Control the filling/packing/cycle time. Cold runner systems   Hot manifolds / runnerless