Zinc die casting process
The process of zinc die casting involves the injection of molten zinc into molds or casts by using very high pressure. Four essential steps are undertaken in zinc die casting, first of which is spraying the mold with lubricant and closing the die cast. The lubricant is used not only to facilitate casting removal but also to contribute in controlling the temperature of the die during the casting process.
Next, high pressure is used to inject or shoot the molten zinc into the die. The pressure is maintained once the die is completely filled and the casting has solidified. After the casting has cooled enough, the dies are then opened and ejector pins remove the shots inside. Scraps are separated from the castings, oftentimes through a special trimming device in a hydraulic press or power press. Secondary operations may be necessary in some zinc die casting that could entail plating, painting or buffing or tapping a hole in the cast parts.
The high-pressure injection is the most critical step in zinc die casting. The entire cavity of the die cast or mold has to be completely filled with the molten zinc before any of the casting’s part solidifies. If the injection or shot is swift enough, there won’t be casting discontinuities even in thin, difficult-to-fill sections of the die cast.
