What is Pressure Die Casting?

Pressure die casting is a fast, reliable, and affordable process for the production of great volume, net-shaped metal parts with strict tolerances. Typically, this process includes injecting a metal alloy under low or high pressure into a tool or mold. It will solidify fast to produce a net-shaped part. After this, automatic extraction follows. 

Two Types of Pressure Die Casting

The two types of pressure die casting will depend on the pressure used – Low pressure die casting, and the high pressure die casting. The high pressure die casting has more than 50% of all the light-alloy casting. At present, low pressure accounts for 20% of the overall production, but its use is growing fast. 

High-pressure casting used for casting requires tight tolerance and intricate geometry as the added pressure can push the metal into better features in the mold. In contrast, the low pressure is for more significant and non-critical components. But, the machine and its dies are quite costly, and because of this pressure, die casting is best only for bigger production. 

High-Pressure Die Casting 

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The injected liquid metal is then subjected to high pressure and high speed into the metal mold. You will find 2 vertical platens in the machine – the fixed platen and the movable. Bolsters should be placed on the platens and hold the die. 

Pour a considerate amount of metal in the shot sleeve and then introduce it into the mold cavity. You can do this using a hydraulically-driven piston. Then the metal solidified, the die opened, and removed the casting. 

Low-Pressure Die Casting

The low-pressure type of casting is done if you are using aluminum alloys together with magnesium as well as other low melting point alloys. Castings of aluminum were weight ranges from 2 to 150 kilograms are the standard feature. 

The process starts with a metal die placed above a sealed furnace with molten metal. Then a riser extends from the bottom to the molten metal. The riser with refractory-line is extended at the bottom of the die to the liquefied metal. 

The low-pressure air is then introduced in the furnace. The molten metal will rise up in the tube and then enter the die cavity with low turbulence. Once it solidifies, the air pressure is later released. The metal that remains melted will then fall back into the furnace. After continued cooling, the die opens and extracts the casting. 

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