In the process of die casting of casting zinc alloy, it is necessary to determine the die casting process according to the structural characteristics, technical requirements, production batch, production conditions and other factors. Its main content includes casting position, parting surface, die casting process parameters (machining allowance, drawing inclination, casting fillet, shrinkage rate, core, etc.) determination, and then use the specified process symbols or words to draw the die casting process diagram. Die casting process drawing is a technical document to guide zinc alloy die casting, and also the main basis for acceptance of zinc alloy die casting.

1. Determination of pouring position

The position of the zinc alloy die cast in the casting mold is called the casting position. The casting position has great influence on the quality, dimensional accuracy and the difficulty of molding process. The casting position is usually determined according to the following basic principles.

(1) The important working face or main machining face of the casting is downward or located on the side. During casting, the gas, slag and sand in the metal liquid will float up, which may cause defects such as pores, slag inclusion and sand holes in the upper part of the casting, while the possibility of defects in the lower part of the casting is small and the organization is dense. For the casting position of the machine bed as shown in the figure, the guide rail should face down to ensure the quality of the important working surface. As shown in the figure, the quality requirements of the circumferential surface of the winch cylinder are higher.

(2) The large plane of the casting is poured downward or inclined. Because the hot metal liquid during pouring has strong thermal radiation on the upper part of the casting mold, it causes the top surface sand to expand and arch or even crack, so that the large plane appears sand clamping, sand holes and other defects. Casting defects in the large plane can be avoided if the large plane faces down or the inclined casting method is adopted.

(3) The thin wall of the casting is downward, sideways or inclined. In order to prevent the defects of cold insulation and pouring failure in the thin wall part of the casting, the thin wall with a large area should be placed at the lower part of the casting, or placed at the side wall or inclined position, as shown in the figure.

(4) Most of the thickness of the casting should be placed on the top or on the side of the parting surface. The main purpose is to facilitate the placement of risers in thick places for feeding.