Die casting process explanation

Die casting process is a relatively old processing technology. Generally speaking, the types of pressing are divided into cold chamber die casting and hot chamber die casting.

In fact, the types of die casting can be divided into low pressure die casting, vacuum die casting, extrusion die casting. Live, semi-solid die casting.

Basic parts or accessories can be processed by die-casting. The die-casting process has a wide range of applications, from a small handle to a car rocket shell or an engine shell, all of which can be completed by die casting.

Of course, compared with CNC, die casting parts are generally not as accurate as CNC machined parts compared to CNC machined parts. In general, the types of die casting can be divided

For an excellent die casting parts manufacturer, it is very important to design and create a high-precision die casting mold, because the die casting mold is repeatedly used in the production process of die casting parts.

If your die casting mold is designed or created differently Well, it will greatly increase the production errors of die-casting parts and the amount of material used for die-casting parts, which also leads to the cost of producing die-casting parts.

Introduction of die casting type

Hot Chamber Die Casting

For hot chamber die casting, usually referred to as gooseneck die casting or hot die casting, hot chamber die casting and cold chamber die casting are the two most popular die casting processes, with hot chamber die casting being more popular than cold chamber die casting.

During the die casting process, the cylinder chamber of the injection mechanism is completely submerged in the molten metal pool. A gooseneck metal feed system draws molten metal into the die cavity. This process has higher part productivity compared to the cold room process.

This is a picture about low pressure casting

However, because hot chamber die casting completely immerses the die casting mold in the metal solution, although the production efficiency of die casting parts is accelerated, but at the same time, it also increases the corrosion sensitivity of the machine, so the hot chamber die casting process is most suitable for use with low melting point and high fluidity.

Metals, such as copper, zinc, magnesium, lead, for this reason, in Asian regions such as China, die casting types can also be divided into:

1.Zinc die casting or zinc alloy die casting

2.Magnesium die casting or magnesium alloy die casting

3.Copper die casting or copper alloy die casting

4.Lead die casting or lead alloy die casting

In the meantime, you can also check out our What Is The Difference Between Cold Chamber Die Casting And Hot Chamber Die Casting? article to help you understand.

Cold Chamber Die Casting

Cold chamber die casting is very similar to hot chamber die casting, if hot chamber die casting increases the production efficiency of die cast parts by increasing the machine’s susceptibility to corrosion, while cold chamber die casting is automated or manual injection of molten metal In order to minimize machine corrosion, cold chamber die casting is more suitable for casting metals with high melting temperatures, such as aluminum and aluminum alloys.

Also, you can check out our What Is The Difference Between Cold Chamber Die Casting And Hot Chamber Die Casting? article to help understand.

High pressure die casting

High pressure die casting is a process in which molten metal or molten alloy is pressed into a mold under high pressure and high speed, most often in soft alloys such as zinc and aluminum, and it also has good efficiency in production. Any die-casting process produces die-cast components with thinner cross-sections and wall thicknesses below 0.40mm, depending on the size of your die-cast part and your requirements, of course.

Components produced by high pressure die casting also have a good surface finish. Although the surface finish of die cast parts is more related to the mold, it can save a lot of subsequent surface treatment

Precautions for high pressure die casting:
If high-pressure die-casting is selected for the production of die-casting parts, thick profiles may be more difficult to form, and high-pressure die-casting has a greater chance of porosity.

If the chosen die-casting manufacturer is an experienced die-casting manufacturer, it can be improved to the greatest extent possible. this situation

Low pressure die casting

Low pressure die casting is a casting method in which liquid alloys are pressed into the mold cavity from bottom to top under pressure, and solidified under pressure to obtain castings.

The principle of low pressure casting is shown in the figure below. Dry compressed air or inert gas is introduced into the sealed crucible.

With the help of the pressure acting on the liquid metal surface, the molten metal can be smoothly passed through the runner from bottom to top along the liquid riser. Filling the mold, the filling pressure is generally 20 ~ 60kPa.

When the casting is completely solidified, the gas pressure on the liquid surface is released, so that the unsolidified metal liquid in the riser and the runner flows into the crucible by its own weight, and then the mold is opened and the casting is taken out.

This is a picture about low pressure casting

Vacuum die casting

The process of vacuum die casting is very similar to that of low pressure die casting, except that the die casting mold and the molten metal bath are in opposite positions, and the cylinder chamber can be turned into a vacuum, forcing the molten metal into the mold cavity.

This design reduces turbulence and limits the amount of gas inclusions.

Vacuum die casting is particularly beneficial in applications for post-casting heat treatment. Vacuum die-casting is an advanced die-casting process that eliminates or significantly reduces the pores and dissolved gases in the die-casting part by removing the gas in the die-casting mold cavity during the die-casting process, thereby improving the mechanical properties and surface quality of the die-casting part.

Extrusion die casting

Squeeze casting is a viable solution for casting low-flow metals and alloys.

In this process, molten metal fills an open die and then squeezes closed, forcing the metal into the recessed portion of the die.

Squeeze casting can eliminate defects such as pores, shrinkage cavities, and shrinkage porosity inside the casting, resulting in local plastic deformation, making the castings denser and grainier, and is a supplementary process for subsequent heat treatment.

This process is often associated with molten aluminum and is used in applications requiring fiber reinforcement.

What type of metal is generally used for die casting

Zinc die casting or zinc alloy die casting

When zinc exists as an elemental metal in the die casting process, because it has very good strength at room temperature, when elemental zinc is alloyed with other metals and non-metals, it can be largely Further increase the hardness and fluidity of zinc alloys.

Due to its high dimensional stability, aluminum is used to manufacture thin-walled and complex-shaped components. Because of its corrosion resistance, it is widely used in parts that require high corrosion resistance.

die casting parts

Magnesium die casting or magnesium alloy die casting

Magnesium has low density, one third lighter than aluminum, and its specific strength (ratio of tensile strength to density) is higher than that of aluminum alloy.

it has high fatigue limit; it has good bearing capacity and can withstand greater impact with aluminum alloy good thermal conductivity; good castability; good dimensional stability; easy to recycle; good machinability; good vibration damping performance; superior to engineering plastics in many aspects and can replace engineering plastics; in kerosene, High corrosion resistance in gasoline, mineral oil and alkalis, etc.

die casting parts

Copper die-casting or copper alloy die-casting

Copper has strong stability, belongs to precious metal, and has good electrical conductivity.

It is generally used in wires. Copper alloy die-casting has thermal strength and thermal stability; copper alloy die-casting has high temperature resistance. Abrasiveness; thermal fatigue resistance of copper alloy die castings; toughness of copper alloy die castings; good machinability of copper alloy die castings; good heat conduction of copper alloy die castings.

Copper die-casting or copper alloy die-casting

Advantages of die casting:

Unlike CNC, the advantages of die casting can be connected in series with each other. The advantages of die casting are more reflected in the outstanding performance of different types of die casting, such as:

1. All the special rules of die-casting products can be given in single mold design or mold group design

2. Have higher production efficiency and speed

3. Cost saving, cnc is basically made by material reduction, while die casting does not reduce material, which saves a lot of cost

4. Highly accurate and repeatable reproduction of designs with varying levels of complexity and detail

5. Excellent die-casting service providers can provide you with more complete and strict die-casting solutions.

If you want to know more about die casting, you can also read this  What is Die Casting:Process, Application, Advantages, can help you better understand die casting.

Disadvantages of die casting:

1.Because the development or creation of die-casting molds is a relatively expensive expense, die-casting products are generally produced in large quantities, and small batches will reduce cost-effectiveness relatively.

2.Limited metal fluidity, alloys vary in ductility, which limits the complexity and shape of the finished product.

3.Die-casting machine limitations: The cost of die-casting parts is greatly affected by the machine, the capacity of the die-casting machine limits the product size and range, and the weight limit.

4.During the die casting process, air may be trapped in the mold, causing porosity in the part.

5. It takes a long preparation time in the early stage of creating a mold. Unlike CNC, it is understandable to put into production.

Considerations When Choosing Which Type Of Die Casting

No matter which type of die casting is selected, the die casting service provider is determined according to the end use and function of the customer’s product. In many cases, the die casting solution given by the die casting factory is determined for this purpose, and the customer can decide which die casting solution to use. Program.
The creation of die-casting molds requires a period of preparation and cannot be put into production immediately
If you need very high precision, very high tolerance parts, more should choose CNC plus


There are many types of die casting. Which type of die casting to choose is determined by the end use and function of the product.

An experienced die casting service provider can create more accurate dimensions and dimensions for you in more time.

Clearly defined die cast parts for increased cost efficiency.

If you are also looking for high-precision die-casting service and custom die-casting molds, I think you should choose us Hongjingyuan Hardware, a Chinese die-casting factory specializing in die-casting and cnc for 22 years, we also have our own electroplating factory, oxidation factory, cnc processing The workshop can provide you with more complete one-stop customized die-casting services, precision CNC machining services and surface treatment services.

This article was re-edited on May 29, 2023

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