Die-casting mold

We often need metal parts in various shapes. We use them in our cars, houses, machines, and other infrastructures. Have you wondered how it is possible to make such a detailed shape? Die Casting mold tech has revolutionized our lives. With this method, you can create complex shapes and patterns. Die-casting mold parts are widely prevalent in a wide range of applications.

In this article, we will learn some fundamentals about die-casting mold. In addition, it’s gonna be an excellent guide for those looking for the best die-casting services. You will learn how foundries make die-casting molds. So, sit tight and read this article thoroughly.

die casting mold

Overview of Die Casting

Die Casting is a famous type of metal casting process. As the name implies, this method typically uses specific dies for the job. The shape of the final metal part depends on the shape of the dies. Although there are different types of die casting, the base technology is the same for all. The material used for making these molds is hardened tool steel.

Die casting has a long history. People invented this tech in 1838. In the early times, this application was only for printing purposes. Later, as technology developed, people usually learned how to use this method to create various complex metal parts. Die casting offers several benefits.

  • Die-casting mold typically offers high production efficiency. This part is comparatively faster than other permanent mold casting processes. As a result, you can create hundreds of metal parts in less time.
  • Die-casting mold parts usually come with a smooth surface finish. For HPDC metal parts, this is more obvious. As a result, you might not need additional machining services.
  • The die-casting method is versatile. It generally works with many metals, including aluminum, zinc, and magnesium.
  • Since this method is fast, it generally reduces production costs. Although creating the dies may be expensive, this method is cheaper in the long run.
  • Die-casting mold parts are widely prevalent in many industries. This method makes your car’s engine, gearbox, and structural parts. You may also find similar applications in other sectors as well.

Different Types of Die Casting

Die casting typically has six major types, each with its own perks. Each type is suitably suited to specific applications. Let’s look at their particular technology and product use.

Type #1 HPDC (High Pressure Die Casting)

As the name suggests, this die-casting method requires high pressure for the job. This high pressure die casting technically pushes the molten metal to every mold corner. As a result, you can get very precise metal parts.

In the car industry, engine blocks and gearbox castings are made of high-quality HPDC aluminum parts. Various equipment and infusion pumps are noteworthy in the medical industry. Besides, many aircraft components also need HPDC casting metal parts.

Type #2 LPDC (Low-Pressure Die Casting)

This die-casting method is just the opposite of HPDC. It involves low pressure, typically ranging from 2 to 15 psi. The process is almost similar, but it is generally slower than HPDC. Since it is slow, you can easily control the movement of the molten metal.

LPDC metal parts are widely prevalent for car wheels, cylinder heads, and suspension systems.

Type #3 Gravity Die Casting

This die-casting method uses gravitational force to fill the mold with molten metal. The process typically pours the molten metal into the mold from above, and the liquid flows downwards. It is simple and cheap because it doesn’t need additional forces.

The gravity die-casting method is prevalent in making pipe fittings and various cookware.

Type #4 Vacuum Die Casting

As the name suggests, this casting method involves creating a vacuum environment. It does this before inserting the molten metal. As a result, you don’t get any casting defects caused by trapped gas inside.

Vacuum die casting is suitable for making delicate components. Electronic castings, aircraft parts, and some automotive parts are noteworthy examples.

Type #5 Squeeze Die Casting

Squeeze die casting combines casting and forging. After injecting the molten metal inside the mold, the process applies high pressure during solidifying. Squeeze pressure mainly reduces the porosity defects.

Squeeze die casting is widely popular because of the high strength and density of the metal parts. Some common examples are suspension parts, brackets, and some building components.

Type #6 Semi Solid Die Casting

This process also combines casting and forging. The only difference is that this process uses semi-solid metals. It looks like a slurry consistency. SMDC is highly popular for making many car parts, electronic housing, and medical devices. go to simi solid aluminum die casting page to know more.

What is Die Casting Mold?

The tool used in the die-casting method is generally called a die-casting mold. People also call it a die-casting tool. The process of making this tool is known as die-casting tooling.

The definition says that a die-casting mold is a unique tool used in the die-casting process. Its primary purpose is to shape molten metal into desired forms. In most cases, they generally come with two halves: the fixed and moving die half.

When both halves are closed, they form a cavity inside that mimics the desired part’s shape. A high-quality die-cast mould is essential to ensure the highest accuracy of your finished metal parts. However, there are several components:

Mold Cavity

The hollow space inside a Mold is generally the mold cavity. It actually gives the shape and size of the final metal part. The molten metal is injected into this cavity and solidifies to get the desired form. Note that you must ensure high precision when making this cavity.

Core Pin Die Casting Mold

The core is another vital component of a die-casting mold. It creates features in casting, such as holes or recesses. It mainly creates complex geometries within the metal part. However, depending on the requirements, you can make it using sand or metal. Note that this core must withstand high pressure and temperature during operation.

Ejector Pins

As the name implies, these pins basically eject the movable die-cast mold half from the fixed one. During the design process, engineers carefully place them where they can apply even pressure. The correct design always ensures that the part is not damaged.

Runner System

The runner generally channels the molten metal into the mold cavity. It consists of several tracks that go to different parts of the mold. Proper runner system design is crucial for even distributing molten metal. Overall, an adequate runner system significantly reduces defects.

Overflow System

The overflow system collects excess molten metal during the injection process. As a result, the system can prevent defects caused by trapped air. Note that this system may not be present for some die-casting molds.


Elements like bolts and pins hold the die-cast mold system together. These parts need to be strong and carefully machined. The die-casting method requires high pressure, gas pressure, and heat. Choosing the right materials is crucial to keeping these parts in good shape.

Die Casting Mold Material: Hardened Tool Steel

Hardened tool steel is a general type of steel. It has various grades suitable for specific use. You can achieve steel’s high hardness and strength by the heat-treatment method. However, why are these tool steels so popular?

First, they offer high wear resistance. Second, their toughness usually makes them ideal for many machining jobs. Third, they also give stable dimensions. Finally, and most importantly, they can withstand extreme heat. As you know, this property is crucial for die-casting jobs.

Hardened tool steel has five different groups. Each group is ideal for unique applications.

Cold-working Die Casting Mold Material

The following four grades are widely prevalent in die-casting mold manufacturing.

Grade Carbon Manganese Silicon Chromium Nickel Molybdenum Vanadium
O6 1.45% 1.00% 1.00% 0.8-1.4%
A3 1.25% 0.50% 5.00% 0.30% 0.9-1.4% 0.8-1.4%
A6 0.70% 1.8-2.5% 0.9-1.2% 0.30% 0.9-1.4%
D2 1.50% 0.45% 0.30% 11.0-13.0% 0.90% 1.00%

die casting mold equipment

Hot-Working Die Casting Mold Materials

As the name suggests, these materials are subjected to high temperatures during casting. They are ideal for HPDC die-casting molds. There are various grades: Grades H1 to H13 are usually chromium-based alloys. On the other hand, tungsten alloys are from H20 to H39, and molybdenum-based alloys are from H40 to H59.

Other types

There are other types of die-casting mold steels as well. SKD61, 8407, DIN 1.2343, 2083, and 8418 are noteworthy. These steels offer specific properties. As you know, die-casting methods have different types. Therefore, materials also vary based on these types.

Three Common Types of Die Casting Mold

We can generally divide molds into three types based on the number of cavities. This diversity mainly arises due to specific needs. Different cavity designs allow die-cast mold makers to produce parts rapidly.

Type #1 Single-cavity Dies

As the name suggests, these die-cast molds have a single cavity. Using these dies, you can produce one metal part per cycle. People widely use these molds for simple and low-volume orders.

Using these dies makes design easier, which is their main advantage. However, the speed of output is slower than with multi-cavity dies.

Type #2 Multi-cavity Dies

Multi-cavity dies have more cavities. Using these dies, you can produce multiple metal parts per cycle. This means you can produce more products than single-cavity dies. Therefore, multi-cavity dies are ideal for high-volume orders.

The best thing about these dies is that they offer cheaper production costs. However, they usually have complex designs.

Type #3 Family Molds

In multi-cavity dies you will find the same cavity design but multiple times. You can generally create multiple metal parts per cycle. However, in family molds, these designs are different. So, in one sense, all family molds are multi-cavity molds, but all multi-cavity molds are not family molds.

Aluminum Die Cast Mold: Market Trends

The aluminum die-cast mold market will grow significantly in 2024. According to Persistence Market Research, this market was valued at $301.3 million in 2023. In the future, this sector is expected to grow steadily at 4.8% every year. Experts expect this market will reach up to $481.6 million in 2033.

How are Die Casting Molds Made?

In the preceding section, we have briefly discussed various die-casting methods and molds or tooling types. In this section, we will generally focus on how they are made. You will be familiar with the step-by-step process in every die-casting factory. So, you will know every step of making the molds whenever you plan to make unique metal parts. This is actually important for custom metal parts manufacturing.

Step #1 Designing the Mold

This step is perhaps one of the most important aspects of the process. Here, you will decide how you wish your metal part to appear and what steps will be involved in manufacturing it. Depending on the part’s design, the type of die-casting method must also be properly selected.

Two parameters are essential in this case: a dimensional analysis and a geometric perspective. The dimensional view informs you of how many cavities your metal part has. Which of the single-cavity or multi-cavity or family mold types is required? This design also makes it easy for you to determine the pressure and volume of the casting.

A geometric view that informs you of the level of complication of the metal part and your plan on how to open and eject it. However, it is very important to note the kind of parting line that is used here. You must ensure that this parting line will coincide with the mold opening direction.

Similarly, a die-casting company also considers other important aspects during this step. We will briefly discuss those in the next section.

Step #2 Choosing the Material

The die-casting method usually involves varying pressure and temperature. Therefore, you must select material that is highly compatible with these situations. In general, engineers use various types of tool steels here. In the previous section, we have discussed these tools steel in detail.

Step #3 Machining the Mold

Once your design and materials are ready, you must plan how to shape the die-cast mold. In this case, various machining methods play a crucial role. Engineers prefer CNC machines for making die-casting molds.

As you know, CNC machining offers exceptional precision. You can technically achieve tolerance up to 0.01mm. You have options like CNC milling, drilling, turning, boring, and more.

Step #4 Heat Treatment

Various heat treatments are very important in die-casting mold making. This step significantly improves the machined parts’ strength and durability. Besides, the process makes the mold more resistant to wear and tear.

Common heat treatment methods are quenching, tempering, annealing, and stress relieving. These methods typically ensure the die-cast mold performs well during die-casting.

Step #5 Finishing

After heat treatment, the new die-cast mold needs some finishing touches. These steps are crucial to ensure smooth surfaces and precise dimensions.

Finishing techniques may include polishing, grinding, and sandblasting. The main purpose of all these techniques is to give the die-casting mold parts smoother and better textures. As a result, they can achieve high tolerances.

Step #6 Assembly if necessary

There are times when you may need to make die-cast mold parts separately. When there are many parts, assembly must always be done carefully. The die-casting mold factory always checks to ensure the assembly is lined up correctly.

Step #7 Testing

Once all the steps above are done, die-cast mold manufacturers test these molds in the lab. They run tests to ensure the mold is in good shape and works correctly. These tests tell you that the molds are high-quality.

die casting mold

Key Steps in Die Casting Mold Design

As mentioned in the last part, several key factors are considered when designing a die-casting mold. This section will mainly discuss those and discover why they are crucial in die-cast mold manufacturing.

Actual Part Design

Before making the die-casting mold, engineers create the part itself. For this job, they use various 2D and 3D drawing programs. In most die-cast mold factories, graphic designers typically use SolidWorks or AutoCAD.

During visual testing, you need 2D models. Engineers use this drawing to check the sizes after each stage of production. A well-designed part gives high-quality results. So, whenever you work with a manufacturer, make sure they have these plans before they start making the product.

Die Casting Injection Molding Type

This is a very important factor when making a die-casting mold. Usually, it changes the quality, strength, and finish of the finished part.

Based on this injection, there are six different types: HPDC, LPDC, Vacuum, and more.

When designing the injection type, several factors need to be considered. First, what type of metal are you working with? Second, did you consider parting lines, geometric views, and design details? Third, what is your expected production speed?

When you use the right injection type, the mold will always fill properly, and casting flaws will be less common. Also, the right pick cuts cycle time by a large amount. In general, you can get very good output.

Gate And Runner Design

The gate and runner channel molten metal into the die-casting mold and usually control the flow of the liquid. Proper design ensures smooth and efficient filling and reduces various types of casting defects.

Consider size, location, and shape when designing a gate and runner. The gate must be placed in the right place to minimize turbulence.

Die Casting Mold Base Design

The mold base typically supports and aligns all mold parts. When designing, ensure you have created a robust design. It provides the system’s overall stability.

You should consider the material and temperature here. The mold base must withstand high pressure and temperature. You should also check for proper alignment and fit.

Cooling System

The cooling system helps the mold solidify the molten metal. A proper cooling system typically improves production speed and part quality. However, inappropriate cooling can cause various casting defects. Therefore, ensure an appropriate cooling system when designing a mold.

There are different kinds of cooling systems. People often use water lines and cooling inserts. Cooling plugs are great for places that need to cool down quickly. When you design a mold cooling system, try to balance the heat across the mold.

Venting and Ejection System

The ventilation and ejection system mainly removes trapped air from the mold. The trapped air could either be created by mold or be there before the injection.

When designing a mold, place the vents at high points. In this case, you can use thin vents to avoid flash. Also, put the ejector pins in the right place to prevent damage.

Note that effective venting and ejection systems usually improve part quality. Overall, it reduces cycle times and production efficiency.


Once you have considered all the factors above, the simulation shows you precisely what you have designed. Simulations can help you find flaws and issues with the flow of metal. Die-cast Mold Makers typically use software like MAGMASOFT, ProCAST, and Flow-3D.

Frequently Asked Questions

What metals are used in die casting?

In die casting, the common metals are aluminum, zinc, magnesium, lead, pewter, and copper. These metals are popular due to their low melting point. Besides, they also offer excellent casting properties, strength, and durability. Among all these metals, aluminum is the most popular. It is lightweight and has an excellent strength-to-weight ratio.

Is 4140 a tool steel?

Yes, LSS 4140 steel is a type of tool steel. This alloy offers excellent hardness, strength, and wear resistance. It is an excellent tool steel for most machining jobs. More specifically, you can find its use in various rotating components. For example, axles, drive shafts, gears, and spindles are noteworthy.

What kind of steel is used for die casting?

The kind of steel mainly varies based on the type of die-casting method. For HPDC die-casting molds, H series tool steels are widely prevalent. On the other hand, for LPDC or cold-working jobs, the O, A, and D series of steel tools are famous. Some special grades are also there, like SKD61, 8407, and 8418.


Die casting is crucial for making many complex metal parts. You can create die-casting parts through various methods. HPDC and LPDC are the two most common methods you will use in a die-casting mold company.

Die-casting mold has three types:  single-cavity, multi-cavity, and family molds. Each type is suitable for specific production requirements.

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