Pressure Die Casting is a manufacturing process done by injecting molten metal into a die cavity applying an external force. Pressure Die Casting is much faster and more efficient than an ordinary die casting process.
Pressure Die Casting is classified into two types based on the extent of pressure applied. They are,
High-Pressure Die Casting
Low-Pressure Die Casting
When talking about Pressure Die Casting, most people actually refer to High-Pressure Die Casting. Because High-Pressure Die Casting is more common. Low pressure Die Casting is still not so popular due to some drawbacks.
This process involves forcing molten metal inside the die cavity under very high pressure and speed. It is the most commonly used die casting technology used by the manufacturer. Nearly 70% of the pressure die-cast parts are made by high pressure die casting.
Process of High Pressure Die Casting
High Pressure Die Casting can be done using two different processes. They are,
Cold Chamber Process
Hot Chamber Process
Cold Chamber Process
The cold chamber process is used for casting metals with a high melting point. The process of High Pressure Die Casting using the Cold Chamber Process is explained below:
The metal is melted in a separate furnace and carried into the shot sleeve using a ladle.
A plunger rapidly forces the molten metal into the die cavity under high pressure.
In the case of a vacuum-assisted system, a vacuum will be created during the metal injection for reducing porosity.
After the metal injection is complete, the casting is left for a while for solidification and cooling.
Then the casting is collected and the machine is prepared for the next casting cycle.
Hot Chamber Process
The hot chamber process is used for casting metals with a low melting point. The metal is melt inside the machine in this process. The process is described below:
The metal is melted inside a furnace that is linked to the die cavity via a gooseneck.
A plunger uses high pressure to force the molten metal to travel through the gooseneck and fill up the die cavity.
A vacuum may be created during the injection in vacuum-assisted systems.
The Metal is allowed to cool down and solidify.
After retrieving the casting the next cycle can be started immediately as there is no need to carry the metal into the machine.
Except for the metal melting part, both Hot and Cold Chamber processes are quite similar. Here’s a video that will help you get a visual representation of the high pressure die casting process.
Advantage of High Pressure Die Casting
The Advantages of High Pressure Die Casting are described below:
This is a speedy process, so casting cycles are shorter incorporating a rise in production capacity.
The high pressure allows the molten metal to reach any recesses. So, castings with intricate details and thin walls are possible.
Die-cast parts have a nice and smooth finish.
The entire process can be automated, so work efficiency and accuracy are higher.
LOW PRESSURE DIE CASTING
Low Pressure Die Casting is done using less pressure and a different mechanism. It is usually used for die castings large parts with simple geometric features. It is less popular than high pressure die casting and currently, about 30% of manufacturers make use of this process.
Process of Low Pressure Die Casting
The Process of Low Pressure Die Casting is explained below:
The metal is molten inside a sealed furnace.
The dies are clamped together and placed on top of the furnace opening.
The die cavity is connected to the furnace by a riser tube.
Low air pressure is applied from within the furnace that causes the molten metal to rise towards the die cavity.
The pressure is maintained until the casting has solidified inside the dies.
Once solidified, the pressure is released and the metals in riser tube fall back into the furnace.
The dies eject the casting and the next casting cycle starts.
Advantage of Low Pressure Die Casting
The advantages of Low Pressure Die Casting are described below:
Production cost can be often less than high pressure die casting.
There is less turbulence during the metal injection, so castings are relatively pore-free. So, parts can be given heat treatment.
Has a good production rate for simple and large castings.
IMPACT OF PRESSURE DIE CASTING IN THE INDUSTRY
Pressure Die Casting is widely used in the industry for the rapid production of complex parts with high-precision and durability. So, there has been a significant rise in the popularity of pressure die casting in recent years.
According to Grand View Research, In 2018, Pressure Die Casting alone had nearly 58.6% share of the global die casting market. This is predicted to significantly increase in the upcoming days.
Following Industries extensively use the Pressure Die Casting process for manufacturing,
Due to the convenience of Pressure Die Casting, more and more industries are shifting to Aluminum Pressure Die Casting for cheaper and better quality parts.
WHICH PRESSURE DIE CASTING PROCESS IS BETTER?
Regardless of which process you choose, Pressure Die Casting, in general, is superior to most other die-casting techniques. But High Pressure Die Casting is better for the production of complex parts. It is much faster and economical.
Low Pressure Die Casting has a slower casting cycle which will hamper the production capacity. But can be a better choice in some cases though. Casting high-quality parts with less porosity is possible in this process. But Low Pressure Die Casting is only suitable for large and simple parts. Complex parts with thin walls are hard to cast using this process. But it is still a better choice than other die casting processes such as gravity die casting.
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