The die casting process involves pouring molten metals with low melting points, such as zinc and aluminum, into a die casting mold and allowing it to cool. Depending on the melting point, it occurs under two different mechanisms (hot chamber casting and cold chamber casting), suitable for the manufacture of simple and complex sheet metal parts.
The process has a unique approach and is responsible for many of the metal parts used to make consumer and industrial products.
Types of Die Casting Process
The two die casting processes used in industry are hot chamber die casting and cold chamber die casting. Each has its own characteristics and is suitable for different scenarios. Here's what you need for both types of procedures.
Hot Chamber Die Casting
The hot chamber die casting process is perfect for processing low melting point materials such as zinc, tin, lead and magnesium alloys. It is not suitable for alloys with higher melting points as it will damage the pump as it will be in direct contact with the metal. It involves melting metal and injecting it into a mold using pressure from a hydraulic system.
Cold Chamber Die Casting
Cold chamber die casting is ideal for processing high melting point materials such as aluminum. The process is ideal for such metals because the high temperatures required to melt the material can damage pumping systems.
The process involves scooping the molten material into a cold chamber before injecting it into the mold. The hydraulic system used in the cold chamber process is similar to the hot chamber process. However, it may require more pressure from 2000 to 20000 psi.
Die casting alloy
Most alloys used in die casting are non-ferrous metals with strong mechanical properties. The non-ferrous part is responsible for the low melting point, consistent with strong mechanical properties. The type of properties required depends on the material being processed. Therefore, there are no restrictions when selecting materials. However, here are a few popular alloys:
· Aluminum alloy
Aluminum alloys have unique properties that make them suitable for manufacturing a wide range of products. On the one hand, aluminum alloy 380.0 is the most common material in die casting due to its unique properties. Other alloys include aluminum alloys 360, 390 and 413. You can use aluminum alloys for the following reasons:
high working temperature
excellent corrosion resistance
light
very good strength and hardness
Good stiffness and strength-to-weight ratio
Excellent EMI and RFI shielding performance
excellent thermal conductivity
high conductivity
good finishing properties
fully recyclable
Withstands the highest operating temperature of all die casting alloys
Corrosion resistance
It maintains high dimensional stability and thin walls
· Zinc alloy
Zinc alloys offer incredible strength, toughness, robustness, performance and cost-effectiveness. As such, they are an essential part of the die-casting process, with properties comparable or even superior to other alloys such as aluminium, magnesium and bronze.
You can use a variety of zinc alloys. However, common die cast zinc materials are Zamak #2, #3, #5, #7, ZA8 and ZA27 which have the following properties:
Improve castability
shorten cycle time
Extend mold life
ideal mechanical quality
· magnesium alloy
Magnesium is another material used in die casting. It comes in a variety of alloys, but the most common is AZ91D, known for its toughness, durability, lightness and good castability. It is 75% lighter than steel and 33% lighter than aluminum without loss of strength. Most hobbyists prefer magnesium because it is better suited for complex castings with tight tolerances and has better corrosion resistance.
· Other alloys
Other alloys suitable for making die castings include bronze, brass, lead and tin.
Due to its high fluidity, tin was the first material used in die casting. It has a low melting point and causes little wear to molds.
Bronze (white bronze) is the correct die casting material to use in the jewelry industry. It is similar in color to platinum and stainless steel alloys, but is suitable for die casting due to its low melting point.