Let's explain what plastic injection mold is first:
Injection molded parts are created by pouring raw plastic resin into a hopper, then heating the resin and injecting it into a custom mold. Pressure is used accommodate shrinkage and once the plastic molded part has fully cooled, the mold is opened, and the parts are removed. Because of the tight tolerances, plastic injection molding is a suitable option for both standard and intricate plastic molded parts of all sizes.
· A sprue(Sprue (Bush) – Tapered hole in the center of the plastic injection mold into which the flow material travel from the nozzle of injection machine to runners) is simply the channel that guides molten plastic from the nozzle of the injection molding machine to the entry point for the entire injection mold tool. It is a separate part from the mold tool itself. A runner(Runner– Connect the sprue bush to molding cavities, it is a passageway of flow material, the section shape is usually round or trapezoid.) is a system of channels that meet up with the sprue, typically within or as part of the mold tool, that guides the molten plastic into the part cavities within the mold tool. Lastly, the gate(Gate–The narrowest position of the runner, where the flow material enters the molding cavity.) is the part of the channel after the runner that leads directly into the part cavity. After an injection mold cycle (typically only seconds long) the entirety of the molten plastic will cool leaving solid plastic in the sprue, runners, gates, part cavities themselves(Mould Cavity(include cavity and core)– The space in the mold shaped to produce molding product.), as well as a little bit of overflow potentially on the edges of the parts (if the seal isn't 100% right).
