Die casting is the process through which many different metals are converted into mould from their molten state. The molten metal is forced into a mould cavity under high pressure. In precision die casting, the mould cavity is made up of two steel dies. With precision casting, precision-sized castings are obtained.
Die castings are made with non-ferrous metals like zinc, aluminium, and alloys of tin. Depending on the type of metal used, the type of machine (hot/cold chamber) is used to make the cast. The process is best suited for high-volume items. As the casting equipment makes up a big part of capital costs, the cost per item remains low.
The precision die casting method ensures that the manufactured products have excellent finishing and dimensional consistency with accurate measurements.
Types of die casting
- Hot chamber die casting
In this type of casting, the chamber for the injection mechanism is immersed wholly in the molten metal. Direct immersion is a fast process, resulting in high production rates. It eliminates the need of transferring the metal from the furnace. It works well with low melting-point metals like tin, zinc, and lead.
- Cold chamber die casting
In this, the molten metal is put into the injection system (the system is not immersed into the molten state). It is a slower process, but great for alloys that have high melting points like brass, magnesium, and aluminium.
Materials used in die casting
There are a variety of metals used for die casting. But corrosion resistant and optimal density alloys or metals are the most suitable. When picking the right alloy, the following things should be considered:
- Strength
- Hardness
- Elongation
Based on these mechanical properties, the most used metals and alloys are aluminium, magnesium, copper, and zinc.
Steps of precision die casting
Precision die casting involves the following steps, namely:
- Clamping
The halves of the die are clamped together with great force for keeping it secure when the metal is injected.
- Injection
This step includes the injection of molten metal into the die. The method of transfer on the type of machine used – whether it is a hot chamber or cold chamber machine.
- Cooling
The molten state of the metal is left to cool down and solidify on entering into the die cavity.
- Ejection
Once the metal has cooled down, the two halves are opened, and the casted metal is pushed out with the help of an ejection mechanism.
- Trimming
If the casting has access material, it is trimmed from it.
The type of die casting depends on your project’s type. You need to pick the right process for your application.
