Aluminum Die Casting Manufacturer | YZDIECASTING
Magnesium Die Cating Manufacturer | YZDIECASTING
High pressure die casting (HPDC) is a widely used manufacturing process for producing complex metal parts. In this process, molten metal is injected at high pressure into a steel mold cavity to create the desired shape. The pressure parameters play a crucial role in determining the quality and consistency of the final product. In this article, we will discuss the pressure parameters used in high pressure die casting and their impact on the casting process.
- Injection Pressure:
Injection pressure is the pressure at which molten metal is injected into the mold cavity. The injection pressure depends on various factors such as the size and shape of the part, the type of metal used, and the design of the mold. The injection pressure should be high enough to fill the mold cavity completely but not too high that it damages the mold or creates porosity in the casting.
The injection pressure typically ranges from 1500 to 2500 bar (21800 to 36250 psi) for aluminum and magnesium alloys, and up to 4000 bar (58000 psi) for zinc alloys. Higher injection pressure helps in filling the mold cavity quickly, reducing the cycle time and increasing productivity.
- Holding Pressure:
Holding pressure is the pressure maintained on the molten metal after injection until the solidification of the casting is complete. The purpose of holding pressure is to prevent the metal from shrinking as it cools and solidifies. Holding pressure also ensures that the casting is free of voids and has a uniform density.
The holding pressure is typically lower than the injection pressure and ranges from 300 to 700 bar (4350 to 10150 psi) for aluminum and magnesium alloys and up to 1200 bar (17400 psi) for zinc alloys. The holding pressure is maintained for a few seconds to a few minutes, depending on the size and thickness of the part.
- Die-closing Pressure:
Die-closing pressure is the pressure applied to close the two halves of the die before injection of the molten metal. The die-closing pressure ensures that the two halves of the die are tightly closed, and there is no leakage of the molten metal during injection.
The die-closing pressure typically ranges from 80 to 200 bar (1160 to 2900 psi) for aluminum and magnesium alloys and up to 300 bar (4350 psi) for zinc alloys. The die-closing pressure is maintained until the solidification of the casting is complete.
- Die-Opening Pressure:
Die-opening pressure is the pressure applied to open the two halves of the die after solidification of the casting. The die-opening pressure should be sufficient to separate the two halves of the die without damaging the casting.
The die-opening pressure typically ranges from 20 to 80 bar (290 to 1160 psi) for aluminum and magnesium alloys and up to 120 bar (1740 psi) for zinc alloys. The die-opening pressure is applied after the casting has cooled and solidified, and the ejector pins push the casting out of the die cavity.
- Shot Sleeve Pressure:
Shot sleeve pressure is the pressure applied to the molten metal in the shot sleeve before injection into the mold cavity. The shot sleeve pressure ensures that the molten metal flows smoothly and evenly into the mold cavity.
The shot sleeve pressure typically ranges from 200 to 400 bar (2900 to 5800 psi) for aluminum and magnesium alloys and up to 800 bar (11600 psi) for zinc alloys. The shot sleeve pressure is maintained until the injection of the molten metal is complete.
- Overflow Pressure:
Overflow pressure is the pressure applied to the overflow well in the mold cavity to ensure that excess molten metal flows out of the cavity during injection. The overflow pressure prevents the formation of flash or excess material on the casting.