We previously discussed lost foam casting. This time, we will discuss pressure die casting. This pressure die casting is a type of modern casting.
What exactly is pressure die casting?
Pressure die casting is also referred to as pressure casting. What is the significance of the term “pressure casting”? Because the metal liquid is injected into the mold at a specific pressure. The mold used in pressure die casting is made of metal and can be reused, or what is commonly referred to as a permanent mold.
Pressure die casting is classified into two types based on the amount of pressure applied: high pressure and low pressure. The pressure is what distinguishes the two. The pressure at high pressure can reach 200 bar, while the pressure at low pressure starts at 2.5 bar.
Die Casting Machine
The melting unit, injection unit, and die unit are the three main components of a die-casting machine.
Melting unit
A melting unit is a tool that holds liquid metal. The melting unit could be a casting furnace that melts metal.
Injection unit
The injection unit presses or injects the molten metal from the melting unit into the die unit.
Die unit
Die units are permanent molds, typically made of metal, with cavities shaped like casting products that will be filled with molten metal. The mold is made up of two parts: a fixed die and a movable die. When the molten metal solidifies, the movable die opens, and the casting object is pushed by ejector pins.
Okay, now let’s discuss the stages of pressure die casting. See the explanation below.
Stages of Pressure Die Casting
1. A hot chamber or cold chamber system is used to insert metal liquid into the shot chamber. The following is the difference between a hot chamber and a cold chamber:
Hot Chamber:
- Melting units and injection units are not separated, so they do not require a long time during the die-casting process.
- Used on metals that have a low melting point such as lead or zinc alloys.
- The injection cylinder is pneumatically or hydraulically driven.
- The injection cylinder is always submerged in molten metal.
Cold Chamber:
- The melting unit and injection unit are separate. So the molten metal needs to be poured first from the melting unit to the scoop and taken to the injection unit to be poured and then injected into the mold.
- Used in metals that have a high melting temperature, such as aluminum and magnesium.
- The injection cylinder is driven hydrolyzed.
- The injection system is only in contact with the metal melt for a short time (only when the metal liquid is injected into the mold) so that the injection system can last longer.
2. The moveable die is brought close to the fixed die, closing the mold cavity tightly.
3. The liquid metal that has been introduced is then pushed by the plunger with a certain amount of force to fill the entire mold cavity.
4. The molten metal in the mold cavity is left to cool until it solidifies.
5. After the cast metal has cooled, separate the moveable die from the fixed die to allow the mold to open.
6. Push the casting object off and out of the mold cavity using the ejector pins.
7. Clean the surface of the mold cavity of any remaining material so that it is ready for reuse.
Pressure die casting is commonly used for objects requiring high-size homogeneity. This casting method is commonly used in the production of automotive components. Engine blocks, pistons, pump casings, brake levers, and alloy wheels are examples of die-cast products.
That concludes our discussion of pressure die casting. If you have any questions or need more information, please leave them in the comments section or contact our Team directly.