Die Casting Process-Principle: Die Casting is a metal casting process which is characterized by forcing the molten metal under high pressure or under gravity into a mold cavity. The mold is made by using metal which has been machined into a shape similar to an injection mold during the process. Die Casting process is different from Sand casting process w.r.t. the mold.
In Sand Casting Process, the Mould is made up of Sand whereas, in Die Casting Process, the mold is made up of Metal.
Most die castings are made from non-ferrous metals specifically aluminum, zinc, lead, copper pewter, and tin-based alloys.
Example: Die Steel or Tool Steel.
Because of the metal mold, the same mold can be used for producing the infinite number of castings.hence the process is also called a Permanent mold casting process.
- Surface Finish: On the metal molds, the excellent surface finish can be produced. Therefore, the surface finish produced in the casting is excellent.
- Here, no machining is required in the casting process and close dimensional tolerances can be produced directly.
- Thermal conductivity: The thermal conductivity of metal molds is higher.hence the surface hardening heat treatment effect is taking place.
- Porosity: There is no porosity property of the mold hence through Risers must be used.
- low melting point metals: Because of the problem of melting of the metal mold, this process is used only for producing castings with low melting point metals.
To avoid the formation of a bond between casting and metal mold, the Silicon powder will be sprinkled on the mold surface before pouring the molten metal into the casting
Types of Die Casting Process:
1.Gravity Die Casting:
- If the flow of molten metal into the mold cavity is due to the gravitational force, then it is called Gravity Die Casting.
- Because of the problem of flow of the molten metal into the each and every corner of casting cavity due to the gravitational force, the gravity Die casting will be used for producing the simple shape of the castings only.
Ex: IC engine piston made by aluminum alloys.
2.Pressure Die Casting:
- If the external pressure is used for molten metal to enter into the mold cavity called Pressure Die Casting.
- Due to the external pressure, it is possible to flow the molten metal into each and every corner of the complex shape of a cavity. hence the complex shape of the casting can be easily produced.
Ex: Carburettor body made by aluminum alloys
Die Casting Applications:
Die-casting is the largest casting technique that is used to manufacture consumer, commercial and industrial products like
- Parts of a sink faucet
- Connector housing
- Gears etc.
- Most die castings are done from non-ferrous metals like magnesium, aluminum, etc.
Advantages of Die Casting Process:
- An economical process used for a wide range of complex applications.
- A process that can be fully automated
- Post machining can be totally eliminated
- Parts have high dimensional accuracy, close tolerance, and longer service life.
- Mold can be used repeatedly because it is made up of metal.
- No external pressure is required for Gravity Die Casting Process.
The Process was explained briefly with Types of Die Castings, Applications and Advantages. If you have any doubts, you can ask us from the comments section.
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