The gating system of sand casting is used to guide the liquid metal into the mold cavity. According to the casting structure, technical requirements and alloy type, we should select the structural type of sand casting gating system, determine the introduction position and calculate the cross-sectional area size, so as to design a reasonable sand casting gating system. Whether the gating system design of sand casting is reasonable or not is related to whether the liquid metal can fill the mold cavity smoothly, and whether the liquid metal will produce defects such as sand flushing, air entrainment and turbulence in the process of filling the mold cavity. The design of sand casting gating system shall follow the following principles:
① Guide the liquid metal to fill the mold stably and continuously, and do not directly impact the core;
② Control the flow direction and sequence in the mold filling process to ensure that the contour of the casting is clear and complete;
③ Fill the mold cavity in an appropriate time to avoid casting defects such as sand inclusion and cold shut;
④ It has the ability to stop slag and overflow, which is simple and reliable;