Die casting is a much popular manufacturing process that is used to make metal products. Mainly, there are two main die casting process types with many variations in the design. In die casting, molten metal is forced into the mold cavities at very high pressures and the process is best to offer bulk metal parts needing minimal machining after production.
Die Casting Process Types
The different die casting process types are introduced with the same goal, to cast a mold by the use of injected molten metal at very high temperatures. Depending on the type of metal used, the part size, and the mold geometry, die casting process can offer great results over the other methods.
The main types of die casting processes are cold chamber and hot chamber die casting and there are many variations on these two types of processes. These are explained below.
Low-Pressure Die Casting
This variation of pressure die casting is suitable to make aluminum parts that are symmetric around an axis of rotation. For instance, vehicle wheel hubs can be fabricated using low-pressure die casting techniques. In the technique, the mold will be located above the molten metal bath and will be connected to the molten metal through a riser tube. When the die caster increases the pressure inside the chamber, the molten metal will get pulled into the mold.
Squeeze Die Casting
This variation was introduced as a workable solution to cast alloys and metals that has low fluidity. In the squeeze die casting process, the molten metal will fill up the open die which is squeeze closed. Closing the die will force the molten metal into all areas of the molding. This technique can be used to producer very dense products. This technique is often used to cast aluminum parts and is mainly used in applications that need fiber reinforcement.
Vacuum Die Casting
Vacuum Pressure Casting (VPC) is a new process that offers minimal porosity and improved strength to the finished parts. The process is much similar to low pressure die casting, except that the positions of the molten metal bath and the die cast mold are reversed. The cylinder chamber will have vacuum that force the molten metal to the cavity. This design is very efficient as it reduces the amount of gas inclusions and turbulence.
Semi-Solid Die Casting
This process is also called Thixoforming and it delivers maximum density and minimal porosity to the finished parts. The work piece is cut into small slugs with a machine, which are then heated to make the metal reach the phase transition state. When the metal reaches a slushy state, a shot sleeve is used to force the same into the mold cavity. Increased precision is the main benefit of this variation of pressure die casting.