The rubber injection nozzle is controlled by a needle valve for forward flow. Currently, many manufacturers can provide injection nozzles with pneumatic switches as standard equipment and can set them in various parts of the mold. Some mold manufacturers have specifically developed an open cold runner system, which has a very small volume, requiring multiple injection points to be set up within an extremely limited mold space (thereby filling the entire mold cavity). This technology makes it possible to produce high-quality silicone rubber products in large quantities without the need to separate the injection port. If a cold runner system is used, it is important to establish an effective temperature gap between the hot mold cavity and the cold runner. If the runner is too hot, the rubber material may start vulcanizing before injection. But if it cools too quickly, it will absorb too much heat from the gate area of the mold, resulting in incomplete vulcanization.