The traditional die casting process (high-pressure die casting) mainly consists of four steps.

These four steps, including mold preparation, filling, injection, and filling sand, are also the basis for various modified die casting processes.

Lubricant is sprayed into the mold cavity during the preparation process. In addition to helping control the temperature of the dies, the lubricant can also help the castings release.

The mold can then be closed and the molten metal injected into the mold at high pressure, which ranges from about 10 to 175 MPa.

After the molten metal is filled, the pressure is maintained until the castings solidify.

The push rod then pushes out all die castings, and since there may be multiple cavities in a mold, there may be multiple castings per die.

The process of falling sand requires the separation of residues, including mold openings, runners, gates, and flash.

This process is usually done by squeezing the casting through a special trim die.

Other methods of falling sand include sawing and sanding. If the gate is fragile, you can directly beat the casting parts, which can save manpower.

Excess mold openings can be reused after melting. The usual yield is about 67%.

The high-pressure injection causes the mold to be filled very quickly so that molten metal fills the entire mold before any part solidifies.

In this way, surface discontinuities can be avoided even in thin-walled sections that are difficult to fill.

However, this also leads to air entrapment, as it is difficult for air to escape when filling the mold quickly.

This problem can be reduced by placing vents on the parting line, but even very precise processes can leave porosity in the center of the casting.

Most die castings can complete some structures that cannot be done by casting through secondary processing, such as drilling and polishing.

After the falling sand is complete, defects can be inspected. The most common defects include stagnation (underfill) and cold scars.

These defects can be caused by insufficient mold or molten metal temperature, metal contamination, too few vents, too much lubricant, etc.

Other defects include porosity, shrinkage, thermal cracking, and flow marks. Flow marks are marks left on the casting surface by gate defects, sharp corners, or excess lubricant.