Traditional die casting process involves following four basic steps to obtain the desired result. These are the preparation of the die, forcing the metal into the cavity, ejection of the casting from the mold, and the shakeout process. This shakeout process enables the sorting out of excess metal from the final product.
Traditional die-casting is employed by many manufacturers for all kinds of castings like brass die casting and aluminum die casting. However, in traditional casting, numerous variations assist in making the process more efficient and quick. Below are some of the common variations found in the methods of traditional die casting.
Semi-Solid
Semi-solid die casting has few advantages, one of them being that it allows for thinner walls than the regular die casting process. Furthermore, this method allows the manufacturers for creating complex parts. Semi-solid die casting differs from regular die casting in some aspects. In this type of casting, aluminum is heated so as to resemble a solid-liquid state. In regular casting, the metal is injected into the mold after heating to its liquid state.
Pore-Free
Manufacturers use the pore-free method in casting particularly for avoiding the porous nature of castings. This method differs from regular die casting by the addition of oxygen to the die before the castings are made. Adding oxygen aids in the elimination of any excess air present inside the cavity, which will prevent any form of porosity due to gasses. In addition, the pore-free casting method provides better strength to the materials and enables heat treatment and welding much like the conventional process. Zinc, aluminum, and lead are the only metals used for making pore-free castings.
Acurad
Developed by General Motors in the 1950’s, this process enables working quick cycle times of the traditional casting process by merging direct solidification and stable fill. This method utilizes a bottom fill system with a stable flow. Initially, the trial and error were done manually, which were eventually replaced with computers.
The acurad process has led to the development of four new die casting technologies – thermal analysis, indirect squeeze, heat treatable, and flow and fill modeling.
Heated-Manifold Direct Injection
Also called the direct-injection or runner less method, this method is only used for casting zinc. In this method, first, the liquid zinc is injected into the heated manifold, which is then injected into a heated cavity using mini-nozzles. Lower costs are one of the main advantages of this method due to the reduction of the amount of scrap produced.