Die-casting is a manufacturing process utilized for casting metal products, which involves the forced introduction of molten metal into the mold cavities, at very high pressures. It is the most appropriate process for the fast production of bulk metallic parts that needs minimum post-production machining. There are two main types of die casting process: Hot-chamber and Cold-chamber. Let us look into both the types in brief here.
Hot-Chamber Die Casting
It is the most popular type among the two die casting processes, and is sometimes referred to as gooseneck casting. The key feature of this process is that the cylinder chamber of the injection mechanism is immersed in the molten metal bath. Delivery of the molten metal into the die cavity is through a gooseneck metal feed mechanism, which gives the Hot-chamber die casting process its secondary name.
Metals with low melting points and high fluidity are most appropriate for this process. Copper, Magnesium, Zinc, and Lead are some of the metals used in the Hot-chamber die casting process. One of the advantages of this process is that this direct immersion allows for a quick mold injection. However, it comes with the cost of increased rate of corrosion as well.
Cold-Chamber Die Casting
In this process, the immersion of the injection mechanism in the molten metal bath is eliminated. Instead, the melted metal is automatically or manually supplied into the injection system. Machine corrosion remains lower with such a design.
Applications such as the casting of metals with high melting points like Aluminum and Aluminum alloys utilizes this process. This is due to the corrosive nature of these applications that are unsuited for the immersion design of hot chamber die-casting.
Apart from these two, there are also several other variations of die casting process, such as:
Low Pressure Die Casting – Vehicle wheels and other Aluminum components are fabricated using this process. The removal of the feeders from the process ensures high casting yields.
Vacuum Die Casting – Applications that have post casting heat treatment uses are made through this process. The advantages of this process include reduced turbulence and limited gas inclusions. Vacuum die casting also ensures enhanced strength and low porosity to the material.
Squeeze Die Casting – This process is mostly used for the strengthening of fiber, and it is mostly related to molten Aluminum. It allows for casting metals and allows much lower fluidity.
Semi-Solid Die Casting – It provides minimum porosity and maximum density into the casted material. Also called Thixo-forming, this process gives an added advantage of better precision; it is most commonly used for non-ferrous metals such as Magnesium and Aluminum alloys.