Hardware die castings have the following influencing factors: fast liquid cooling speed of aluminum, fine grain, compact structure, high comprehensive mechanical properties, accurate size, smooth surface, improved quality, uncertain factors affecting the quality of castings, especially suitable for mass production, well organized, which can reduce the machining allowance and riser size to the maximum extent. At the same time, the process yield and blank utilization rate are higher than other die castings.

Hardware has high thermal conductivity and small volume heat capacity. During the flow process, the temperature of molten metal will drop rapidly. The molten aluminum has active performance and is easy to be inhaled and oxidized. If the oxide film formed on the casting surface is always complete, it will play a good role in protecting the molten aluminum below and preventing secondary oxidation. If the casting is not smooth enough or smooth enough, the oxide film breaks, and the oxide slag on the surface is mixed into the aluminum liquid below, it is difficult to float to the surface, and various gases are not easy to precipitate. Due to the similar density of aluminum and aluminum oxide, slag is generated in the castings, which has high shrinkage and is prone to shrinkage cavity, porosity, pinhole, slag and other casting defects. Therefore, the stable casting of metal die castings is particularly important.

In practical production, it is difficult to combine the advantages of traditional gravity casting gating system of metal mold. If the filling stability (bottom injection) is emphasized, the reasonable cavity heat distribution cannot be obtained. If the reasonable heat distribution of the mold cavity is emphasized (note above), the stability of the casting will be lost, and nothing will be seen. Therefore, the traditional metal mold gravity casting process has caused a long-term adverse situation of low process yield and low blank utilization.