Gates connect the runner system to the cavity and are the orifices through which the melt enters the mold.
Before designing the runner system, you should run a Gate Location analysis for each cavity to find out the best gate locations. For parts where appearance is important, the gates should be narrow to prevent large blemishes on the surface of the part. A smaller opening will also make gate removal easier.
Make gates short, to prevent large pressure drops and avoid sharp angles between gates and runners, which could contribute to a pressure drop in the system. Make corners rounded, so that the melt flow is not inhibited. The cross-sectional shape you choose for the gate depends on the shape of the runners.
Gates can have many different configurations but they are broadly classified based on the method of gate removal into manually trimmed and automatically trimmed gates. Manually trimmed gates require an operator to separate the parts from runners during a secondary operation.
Gates can have many different configurations but they are broadly classified according to their method of degating into manually trimmed and automatically trimmed gates. Special features are incorporated into automatically trimmed gates so that the gates are trimmed or sheared when the mold opens and the parts are ejected.