Pressure Die Casting

Why Choose RapidDone Pressure Die Casting?

As the prototyping manufacturing expert, RapidDone built up a long relationship with medium-size pressure die casting manufacturer. Over the years, we’ve worked with many clients on thousands of different hpdc die casting projects. With the experience we’ve gained, we can handle parts of different sizes, shapes, and tolerance. Due to the high-quality products we deliver, we have built lasting relationships with many of our clients.

As a one-stop solution provider of on-demand manufacturing services, we keep different CNC machines in-house. These machines include 3-axis, 4-axis, and 5-axis milling machines as well as lathe machines. We also offer outstanding finishing services, including polishing, painting, and silkscreen.

When it comes to costs, we believe our pressure die-cast parts are the most affordable in the industry. Our in-house team is always available to help customers decide between the various options we provide. With their advice, we can generate custom quotes that best suit the needs of the customer.

As an ISO-9001 certified pressure die casting manufacturer, quality is very crucial to us.  Our constant pursuit of quality enables us to gain and retain our customer’s trust. When you purchase RapidDone parts, you can be sure they’ve been tested thoroughly by our in-house QA team.

Finally, to tie it all together, we have a brilliant team of highly skilled engineers and technicians. No matter what you need, there is a team at RapidDone happy to assist you.

What Is Pressure Die Casting

Die casting is a well-known and widely used casting operation. It involves pressuring molten metal into a pre-manufactured mold under high pressure. Typical casting pressures can range between 120 and 1200 bar. Due to the high pressure, the filling speed is also high, which makes the process fast.

Pressure die casting is one of the fastest and one of the most financially efficient casting techniques. What makes it efficient is that it uses only one mold to produce a large number of castings. The castings are done very quickly and with good quality.

The casting process requires permanent metal molds. Metal molds are expensive, but they are reusable after the completion of the casting process. It reflects in the product’s unit price, as the manufacturing cost decreases by a large margin.

Pressure Die Casting Process Procedure

It is a little similar to our plastic injection molding, the whole process includes two processes: The tool-making process and the casting process.

1. Tool Making Process

The mold’s tooling is an important step in the casting process. Before the casting starts, we set up a plan covering the design and making of the tool. Let’s take a look at the steps we follow in our tool-making methodology:

• Create a design scheme for the manufacturing process.
• Check and choose the suitable mold tools material.
• Manufacture the molds using CNC machines and heat treatment processes.
• Start the casting process to create some samples with full control of all process steps.
• Check the surface finish and perform any required post-process fabrication.
• Visual and detailed inspection of the finished part to check if the product meets the requirements.

2. Casting Process

The casting process can be summarized in 3 simple steps: mold filling, cast curing, and part removal. Casting takes a short time, making it a very reliable method for the mass production of parts.

Let’s go through the steps involved in the casting process:

A. Mold Filling

The casting process starts with spraying a release agent into the mold. The release agent makes it easy to remove the part from the mold after casting. Common release agents include water-based chemicals.

The next step involves adding the melted alloy to a chamber in the die casting machine called the casting chamber. A piston pushes the molten metal through some channels until it reaches the mold’s cavity and fills it up. The piston assembly is known as a casting set.

B. Cast Curing

After the melted alloy has filled the mold, high pressure is applied to the mold. The high pressure ensures the molten alloy enters all the mold’s areas and also solidifies the cast. It’s necessary for a high-speed, detailed, and defect-free casting.

C. Part Removal

When the pressure reaches a certain limit, the latches of the mold are opened. Ejection pins that are operated automatically are used to push the part out of the mold after the gate is opened.

Pressure Die Casting Materials

1. Mold tools

The molds used in die casting must be manufactured from high-quality steel with high heat resistance.  At RapidDone, we use H13 tool steel and S136 steel with a Rockwell hardness of 40-55.

2. Die-Cast parts

The materials used in pressure die casting are usually non-ferrous metals. The weight, properties of the material, and budget are the factors that determine the type of alloy we select.

The most common material in die casting is aluminum, the process is called as aluminum pressure die casting. It occupies a percentage of more than 80% of the materials used in casting. Magnesium and zinc are the next popular materials, while tin and copper are the least used in die casting.

Aluminum and magnesium are metals with high melting points (above 500 C). They are cast using the Cold chamber process( we’ll cover it later). That is the reason why the cold chamber is more popular than the hot chamber process.

Pressure die casting also gives the materials some advantages after the casting process. These properties include high resistance to corrosion, high hardness and strength, and high conductivity (thermal and electrical).

Tolerances In Die Casting

Due to the high pressure die casting uses in the process, the quality of the finished product is very good. Pressure die casting can achieve products with detailed features and small tolerances, such as thin-walled vessels or cylinders.

The tolerances achieved with the process can reach up to 0.1 mm. These very low tolerances result in pressure die casting being used to manufacture lightweight, complex components.

Pressure Die Casting Products And Application

Pressure die casting has several uses in many industries for different applications. The following is a list of the  industries that use pressure die casting:

• Automotive Industry.
• Aerospace Industry.
• Machines Industry.
• Electronics Industry.
• Furniture Industry.
• Appliances Industry.
• Power tools Industry.

Although all these industries rely heavily on pressure die casting as one of the main components manufacturing processes, the Automotive sector uses pressure die casting the most in components manufacturing.

Over 80% of the casts produced using pressure die casting worldwide come from the automotive industry. Pressure die casting products such as pistons, cylinder heads, shafts, and manifolds are examples of automotive parts made using die-casting processes.

The reason for the heavy usage of this process in the automotive industry is the tendency to use aluminum alloys in vehicles. Aluminum is lightweight so, it reduces the overall weight of the vehicle’s mechanical parts. The cold chamber die-casting process is also efficient and cheap, making it very attractive to the auto industry.

Pressure Die Casting Defects

Each product manufacturing process can produce undesired irregularities in the final product. These are called process defects. In the die casting process, two defects occur frequently: misruns & cold shuts. Several factors can cause these defects. Let’s look at some of these factors:

• Low die temperature.
• Low metal temperature.
• Metal not clean enough.
• Poor venting.
• Excess use of lubricant.

Some other defects can happen during the die casting process. They include shrinkage porosity, gas porosity, flow marks, and hot tears.

These defects occur due to bad gating, sharp corners, or excessive usage of lubricant.

Pressure Die Casting Cost

The costs for any pressure die casting operation can be broken down into three main parts. Let’s look at these costs:

1. Setup Costs

Setup costs refer to the costs of the activities done to prepare for the casting activities. The most prominent cost among all these is that of tool design and manufacture. Tooling for the die-cast process is often very expensive. The cost is dependent on the size and complexity of the part.

2. Process Costs

Process costs are the actual costs incurred during the production of the die-cast parts. It includes labor, electricity, and material costs. The magnitude of these costs also depends on the quality and complexity of the parts.

3. Finishing Costs

The finishing costs refer to the operations carried out after casting to give the parts the required finish.  These post-production activities include machining, painting, polishing, etc.

Pressure Die Casting Machines

There are two types of machines used in die casting: hot chamber and cold chamber machines. Both of them consist of a power cylinder, a nozzle, and a cup for adding the molten metal. The difference between them is the position of the power cylinder to the cup.

In a hot chamber machine, the cylinder is always in direct contact with the molten metal. This is the reason why the hot chamber machine is suitable for low melting point metals.

On the other hand, in cold chamber machines, the casting set is located outside the melt. The piston doesn’t stay in contact with the molten metal at all times. This is why it’s suitable for high melting point metals like aluminum.

The piston used in both processes is driven differently depending on the machine’s manufacturer. Some models use hydraulic power, some use pneumatic power, and some use ordinary mechanical motion to deliver the power to the piston.

Advantages Of Pressure Die Casting

Pressure die casting is widely used in industry (especially in automated industries) because of the advantages of the process. Some of the process advantages are as follows:

• High Speed: Pressure die casting machines use short casting cycles. They can perform several cycles in a short time (up to 15 cycles in a single minute).
• High accuracy: Pressure die casting can produce parts that have thin, complex features with extreme accuracy. It also finds applications where low tolerances are needed.
• Surface finish: The pressure dies casting process produces a very smooth surface finish. This is an important requirement in some industrial fields like the automotive and aerospace fields.
• Automation applicability: Pressure die casting machines are capable of performing continuous cycle operations. In automated industries, this makes them the preferred choice.

Disadvantages Of Pressure Die Casting

Pressure die casting has some disadvantages too. Most of them are related to the high costs it demands, but also there are some other drawbacks to the process. Let’s take a look at some of these drawbacks:

• High Cost: The initial investment required (machines and molds), as well as the operational cost, is very high. However, it is easy to get the initial investment back during mass production.
• Product Strength: Tests on parts made using die casting have shown that their strength may be lower than those made with other methods. The lower strength is due to the forces applied to the metal in the hardening stage.
• Weight Limit: There is a weight limit on the parts that can be manufactured using pressure die casting Pressure casting machines cannot produce casts over a certain weight due to the locking force capacity.
• Complex Dies: The dies used in the machine to produce the final product are always complex in shape and hence expensive.

Finishes For Pressure Die Casting Product

Several finishes can be applied to the die-cast product once the casting process is complete. These finishes provide durability, a good appearance, and protection against rust and other climatic factors. These finishes can be listed as follows:

• Painting: Painting the part gives it a good appearance and also some protection. A coating is applied to the surface before painting to ensure the paint adheres to it.
• Powder Coating: This finish is applied to the surface to hide any flaws or manufacturing defects on It also provides anti-corrosion protection.
• Antiquing: Antiquingfinish is very popular with zinc castings. It involves electroplating the metal with copper or copper sulfide. It gives the cast an antique decorative look.
• Ceramic Coating: It has the advantage of being a thin coating. It can even be applied to the threads of a screw. Ceramic coatings have a drawback though their thin thickness cannot hide flaws in the cast.
• Plating: Plating is the worst finishing process for hiding flaws on the finished surface. However, it increases the surface’s electrical conductivity.

If you want to learn more about our surface finishing service for your parts, you can talk to our team.

Recommended Tips For Pressure Die Casting

There are four simple tips that the manufacturer and product designer need to follow to ensure a perfect die casting experience. Let’s list and explain these tips below.

1. Geometry and Design Points Verification

The designer must consider design limitations and part geometry before using the die casting process. Some design tips to ensure a successful casting are:

• Add more support to the design using ribs.
• Eliminate sharp edges and corners using fillets.
• Add mounting points when required using bosses.

2. Monitor The Mold Tools’ Lifespan

The lifespan of the mold tools must be known before the casting process. Continuous monitoring and active maintenance are also needed to ensure the desired quality.

3. Extend The Molds’ Lifespan

Heat treatments and die coatings can help extend the mold’s lifespan. The treatments may add extra cost to the molds, so you need to compromise between price and mold quality.

4. Choose The Right Casting Material

Each material offers different mechanical advantages and disadvantages. After factoring in the cast’s intended application and the cost, you have to choose the best fit.