What Is Hot Chamber Die Casting?

Hot chamber die casting is a very useful manufacturing process. It can be used to process metals with low melting points, such as magnesium, lead and zinc. For manufacturers, this high-pressure die casting method offers many advantages, such as high throughput, low maintenance and low waste. The hot chamber die casting process can be used for a wide range of materials and it is very versatile. In industrial production, it is widely used in electronics, aerospace, automotive and other industries.

We will discuss all about hot chamber die casting in this article. We will mainly discuss its process, parts, advantages and disadvantages and its applications in industry. Finally, to illustrate its importance, we will make a brief comparison with the cold chamber die casting process.

What is Hot Chamber Die Casting?

Hot chamber die casting requires a mold with a cavity filled with molten metal. When the metal cools and hardens, the mold is opened and the part is ejected. This completes the cycle. If the part needs to continue to be manufactured, then the cycle continues.

Since hot chamber die casters can only be used to cast metals with low melting points. Therefore the furnace can be placed right next to the die casting machine without causing damage. Since there is no need to transfer the molten metal from the furnace to the die casting machine. This method is therefore very efficient and saves operating time. On the other hand, the injection unit allows the metal to be injected directly from the furnace into the mold.

Therefore, the main feature of hot chamber die casting integrated furnace and mold setup. This not only makes it possible to manufacture parts at a faster rate, but also produces better parts at a lower cost. On the other hand, in cold chamber die casting process, the furnace is usually a separate machine from the mold. In this way, high temperatures do not damage the die casting machine.

Components of Hot Chamber Die Casting

A hot chamber die casting machine is a complex machine that consists of many components. Next, let us understand its composition.

Furnace

The built-in furnace is the most important part of this machine. Inside the furnace, there is a combustion chamber in which the fuel is burned to produce extremely high temperatures which melt the raw material. In a hot chamber die casting machine, the furnace is close to the mold.

Gooseneck Tube

This is an important part that can only be found in a hot chamber die casting machine. The gooseneck pipe connects the pump that injects the metal and the pipe that leads the molten metal into the mold. It is located inside the molten metal pool. Therefore, it needs to be extremely heat resistant and able to cope well with high temperatures. For this reason, goosenecks are usually made from high-quality cast or forged steel.

The hot chamber and plunger are part of the hydraulic injection system and are located inside a cylindrical bushing. In addition, most goosenecks are replaceable. This is because they deteriorate in quality after a period of use in harsh environments.

Nozzle

The nozzle controls the flow of liquid metal through the gooseneck into the mold. It acts as a gate in order to allow the metal to enter the mold smoothly and in the correct direction. Any excess material at the end of the casting cycle is returned to the furnace through the nozzle.

Plunger or Piston in Hydraulic System

Liquid metal enters the mold through this component and is kept under high pressure. The piston moves up and down in the hot chamber. It is powered by hydraulic cylinders fueled by oil or gas.

Mold

The last part is the mold itself. It usually also has cavities and ejector pins for pushing the part out. Depending on the geometry of the part, it can also accommodate other parts such as cores. In addition, the mold used in the hot chamber die casting process is the same as any other casting process.

Learn more: Comprehensive Guide To Tooling Die Casting Mold Design

How to Do Hot Chamber Die Casting

Now that you have learned about the various parts of a hot chamber die casting machine. Now that you have learned about the various parts of a hot chamber die casting machine. Now that you understand the parts of a hot chamber die casting machine, let’s talk about how it works.

The hot chamber die casting process consists of four main steps:

• Filling the Hot Chamber: The piston moves upward, opening the air inlet and allowing the liquid to enter. Once the air inlet is open, liquid metal from the furnace fills the hot chamber of the hydraulic piston unit inside the gooseneck.
• Injection: As the hydraulic piston moves downward, it forces the liquid in the hot chamber into the mold cavity. The liquid metal enters the mold cavity through a nozzle and fills it.
• High Pressure Die Casting: When the cavity is filled, the piston continues to press downward. This continuously pressurizes the liquid metal to create a high quality casting. The pressure is usually between 5 and 35 MPa, but the exact value depends on the shape and other characteristics of the metal.
• Cooling: Inside the cavity, the molten metal is left to cool. At the end of the cooling cycle, the plunger returns to its initial position and the mold opens, releasing the part. The part can then be post-processed. In addition, the die casting machine can be prepared for a new casting.

Learn more: How Does Metal Die Casting Work?

What Are the Advantages and Disadvantages of Hot Chamber Die Casting?

There are many advantages and disadvantages of hot chamber die casting. Therefore, manufacturers need to be aware of these advantages and disadvantages in order to make an informed choice. Let’s see what these advantages and disadvantages are.

Advantages of Hot Chamber Die Casting

First, let’s talk about the advantages of hot chamber die casting. The hot chamber die casting process is famous because it makes parts quickly, affordably, and with good quality, and the molds last longer.

Fast Production Cycles

Hot chamber die casting is a casting process that does not require high temperatures. This method saves a great deal of time because the metal has a low melting point and can melt or solidify very quickly. In addition, because the hot chamber die casting machine has a built-in furnace. Therefore there is no need to waste time transferring the molten metal into the mold. For these reasons, the hot chamber die casting process can complete up to 15 cycles per minute.

Cost Effective

This method is more economical than other processes such as cold chamber die casting for a number of reasons. First, it is more productive and therefore more profitable. Since the furnace is built into the machine, the equipment requires less space. Therefore, you do not need to provide additional space for a separate furnace. On the other hand, the manufacturer also saves on equipment and personnel costs by not having to transfer the molten metal from the external furnace to the mold.

Longer Tool Life

Since the hot chamber die casting process is typically used to process metals with lower melting points. Therefore, the molds for this process are not subjected to high temperatures. As a result, the molds wear out slower and last longer. This helps the producer to save cost and time.

Less Material Waste

The built-in furnace of a hot chamber die casting machine reduces waste and allows for full utilization of materials. While handling raw materials, spillage and loss may occur. However, this does not happen with this setup.

Disadvantages of Hot Chamber Die Casting

There is no such thing as a perfect machine or manufacturing process. Now coming to some of the disadvantages of hot chamber die casting.

Not many Material Choices

Hot chamber die casting can only be used for low melting point metals such as tin, magnesium and zinc. Therefore, if hot chamber die casting is chosen, engineers can only choose from a few materials.

Unsuitable for Small Batch Production

The use of die casting makes economic sense only when a large number of products need to be produced. This is because it costs a lot of money to manufacture the molds. Before making a final choice, engineers should conduct a detailed cost-benefit analysis of hot chamber die casting to determine whether it is suitable for relatively small projects.

These are the advantages and disadvantages of the hot chamber die casting process. Additionally, when it comes to molding, die casting and injection molding are usually tit-for-tat. It is important to understand both processes if you are choosing the best manufacturing process.

Hot Chamber Die Casting Materials

Because the furnace is built into the die casting machine, this die casting process typically uses low melting point metal alloys. Next, let’s take a look at the common materials used in the hot chamber die casting process.

Zinc

Without a doubt, zinc is the most commonly used metal for hot chamber die casting. Zinc castings are strong, hard and resistant to wear. Zinc can be used in the hot chamber die casting process because it melts at a temperature of 420°C. Zinc is also a good conductor of electricity.

In addition, zinc has good electrical and thermal conductivity. It is therefore ideally suited for parts containing computer circuitry. On the other hand, since zinc flows extremely well when melted. Therefore the dimensional stability is higher and complex geometries such as thin walls can be produced.

Finally, it is an inexpensive raw material that can be reused many times. Overall, it is ideal for die casting processes.

Magnesium

Magnesium is another metallic material for the hot chamber die casting process. It is strong, lightweight, and recyclable. In addition, it has excellent electrical and thermal conductivity, as does zinc. Magnesium, like other metals, has the advantage of high dimensional accuracy and can be used to build thin-walled structures. On the other hand, magnesium also blocks radio frequency and electromagnetic radiation very well, which is a very useful property.

Hot Chamber Die Casting Uses

Next, let’s learn about the areas of application of this die casting process. Next, let’s look at the areas of application for this die casting process. Since they are used in a very wide range of applications, we will briefly describe the most prominent ones.

• Automotive: The automotive industry is a large market for metal die casting. The hot chamber die casting process produces products such as zinc alloy parts for engines and transmissions as well as electronic components such as mirror housings. In addition, high-performance cars often use lightweight magnesium metal castings to reduce weight.
• Housings for Electronic Devices: Magnesium and zinc alloys have excellent electrical conductivity. As such, they are ideally suited for the manufacture of items such as smartphone parts and integrated circuit housings.
• Decorative Items: Sometimes, fine-looking metal alloys such as pewter can be used to make artwork such as jewelry and home furnishings.
• Aerospace: Zinc-magnesium alloys are very useful because they make parts lighter. In addition, engineers use tin alloys to make gas turbine parts and spacecraft engines.

A Simple Comparison of Hot Chamber Die Casting and Cold Chamber Die Casting

There are two main types of die casting processes: hot chamber die casting and cold chamber die casting. We’ve already learned about the hot chamber die casting process. Next, let’s quickly compare the two processes to understand them better.

• Furnace: In a hot chamber die casting machine, the furnace and the mold are one and the same. In cold chamber die casting, they are separate. The furnace is usually located elsewhere in the plant.
• Cycle Time: Because it takes a long time to melt and cool the metal in a cold chamber die casting process. Therefore, this die casting process has a longer cycle time and lower output.
• Materials Used: Hot chamber die casting uses materials such as zinc, magnesium, and tin. The cold chamber die casting method usually uses metals with higher melting points, such as aluminum alloys.
• Safety Measures: The hot chamber die casting process is usually safer. This is because the molten metal is cooler and less fluid. When companies use cold chamber die casting equipment, they must invest more in worker and machine safety.
• Cost: In most cases, cold chamber die casting is more expensive for manufacturers. This is because setting up furnaces and die casting molds is expensive, and energy costs and maintenance are also higher. In addition, the molds have a shorter life span, which is also a major cost of die casting.

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In modern industrial production, hot chamber die casting is an important way of manufacturing products. It combines high pressures and low temperatures and is ideally suited to low melting point metal alloys. It is a very specialized manufacturing process. The hot chamber die casting process has many advantages that can help manufacturers earn more profits. It can produce high-quality parts quickly and in large quantities at a lower cost.

Yonglihao Machinery has professional equipment and a technical team to provide you with the best die casting service. We will help you select the best products for your die casting needs. We will also help you select the casting method that best suits your die casting job, such as a hot chamber, cold chamber, or other methods. If you would like to learn more about hot chamber die casting, please feel free to contact us!