What Are The Different Types of Die Casting Process?

The die casting process is an automated manufacturing technique in which reusable molds (also referred to as tools or dies) are used to create sophisticated geometrical shapes of intricate metal parts. The liquefied metal is poured or filled into the recyclable mold which makes the molten metal contour to the design of the mold. As a result, the metal parts produced are with high-quality precision and accurate dimensional profiles.

CHARACTERISTICS OF DIE CASTING PROCESS

To maximize the full capacity of the production line, the die casting process is much more efficient than the conventional manufacturing methods such as injection molding, sandblasting, and extrusion for diverse components. Also, the die-casting process offers several characteristics, some of which are described below:

• For sturdy, premium-quality, and intricate production of components, non-ferrous metals are rather extensively used, including aluminum, copper, magnesium, zinc, pewter, lead, and sometimes even tin-based alloys. 

• Several key automotive components are manufactured by the cold chamber die casting for their high volume production and low-cost expenditures. The high melting point and abrasive traits of aluminum in the cold chamber die casting process benefit the manufacturing of impressive precision parts for various industries.

• Post-processing is easy to apply to components produced by die casting methods, including sandblasting, lathing, milling, surface plating (coloring), and hard black anodizing.

TYPES OF DIE CASTING PROCESS

The versatile nature of the die casting process has led manufacturers to achieve the specifications of complex design. It has become a design-focused manufacturing technique, giving the metal products an edge of high precision with fewer post-machining treatments.

Based on the preferred material type (metal or alloy), the die casting process can provide remarkable stability by being flexible in crucial areas, such as the geometrical complexity of design, tighter tolerance requirements, finishing sizes, and others.

The die casting process has five major types: the hot chamber die casting, the cold chamber die casting, the injected metal assembly, sand casting, and lost-wax casting/Investment casting. A brief introduction below includes all of the types mentioned above.

1. Hot Chamber

In the hot chamber die casting process, a casting machine has a built-in furnace to melt the metal and is shaped as a gooseneck. Thus, this die casting process is also known as gooseneck casting. While following the gooseneck structure of the machine, the molten metal gets pushed through the cylinder chamber by the hydraulic piston into the metal cavity.

A significant feature of the hot chamber die casting process is that it works great with various low melting alloys such as zinc and magnesium. As a result, the low melting points give the casting die a durable and prolonged die life. Other benefits of the hot chamber die casting process include reduced porosity and a faster process than the cold chamber die casting.

2. Cold Chamber

The cold chamber die casting process proceeds within a horizontal orientation instead of a gooseneck-shaped machine. Although the designed machine for the cold chamber process is different from the hot chamber die casting machine, both approaches are somewhat similar. The prominent distinction occurs at the point of metal casting, which is performed outside the cold chamber machine. Thus, a manual (or sometimes automatic) ladle transfer system collects the externally molten metal and puts it inside the die casting machine.

Finally, the hydraulic valves of the machine stimulate a plunger that performs to shove the liquefied metal into the die using different channels. The cold chamber die casting process gives outstanding results with alloys of high melting points, such as copper and aluminum. Various advantages associated with the cold chamber die casting process involve the resolved corrosion problem and extended operating life by minimizing the contact time, thanks to the separation of the melting pot and injector components.

3. Injected Metal Assembly

The Injected Metal Assembly (IMA) is a die casting process that functions by injecting the already melted material into the die mold at high pressure. After only a couple of milliseconds, the molten material inside the cavity turns solid. It powerfully combines the different small parts into a single machine element.

Consequently, this method also acts as a connecting moderator to compile several small machine parts that fall within 6” in diameter. The most preferred metallic alloy for this particular OEM die casting is often zinc. However, both die casting machines – either hot chamber or cold chamber – can be selected according to requirements. It also supports other materials than metals, including plastics, ceramics, fibers, elastomers, and glass.

The significant advantage of this die casting process is the absolute strength and accuracy provided by the custom-made tools involved only in this production technique. The incredibly tight positional tolerances and the solid mechanical lock between the combined machine components offer longer adherence and cohesion of produced parts. Other benefits of the injected metal assembly method are no special surface preparation, no thermal degradation, bearing harsh environments, and part-to-part consistency.

4. Sand Casting

Sand casting refers to a manufacturing method in which molten metal is poured into a sand mold with a hollow chamber of the required form. Then the mixture is allowed to solidify for some time before being removed from the mold.

It is well known that the sand casting technique has a wide range of applications. Sand castings may produce castings in a wide variety of sizes and weights, with highly complicated geometries, using a large variety of metals. These castings can also be made from a wide variety of materials. The main defining characteristic of the sand casting method is that it involves the use of sand as the molding medium.

Sand is used instead of other materials to build molds, resulting in significant cost savings. Undoubtedly, it is a considerable advantage. The expenses connected with the fabrication of the molds represent a substantial portion of the costs related to the various casting techniques.

Nevertheless, given the characteristics of sand, the molds required for this method cannot be reused and must be discarded after usage. The fact is that keeping the sand mold in one piece after extracting the casting from it is not feasible.

On the other hand, sand casting is suitable for casting metals with high melting temperatures, including titanium, steel, and nickel. This casting method is the only one that can be used successfully with these elements. As a result, the technique has become the method of choice in the automotive and aerospace sectors to produce low-cost, small-series components.

5. Lost-Wax Casting/Investment Casting

The process of investment casting involves coating a pattern made of wax or a compatible polymer by dipping it into a slurry of refractory material. After the refractory material coating has had time to solidify, this dipping procedure is carried out many times to improve the thickness of the layer and its strength. After completing the final coating's curing process, the wax is removed by melting it. Then the liquid metal is poured into the cavity created by the wax pattern. After the metal inside the mold has had time to solidify, the casting may then be removed from the mold by shattering the refractory mold.

Compared to other casting techniques, such as sand casting, investment casting, also known as a lost wax casting, is considered a precision metal casting method because it can produce highly accurate and finely detailed castings. Typical components include turbine rotors, electronics enclosures, gears, valves, jewelry, and dental fittings.

COMPARISON CHART

The following table compares all of the different types of die casting that have been discussed before. (Note that the information shown in the table is not definitive and may be subject to modification based on the requirements or the operating conditions.)

	Hot Chamber	Cold Chamber	Injected Metal Assembly	Sand Casting	Investment Casting
Materials	Low Melting Materials (Zinc, Magnesium, etc.)	High Melting Materials (Copper, Aluminum, etc.)	Metals, Plastics, Ceramics, Fibers, Elastomers, Glass	High Melting Materials (Titanium, Steel, Nickel, etc.)	Gold, Silver, Brass, Copper, Bronze, Aluminum
Safety Measures	Minimum	Maximum	Maximum	Minimum	Minimum
Surface Finish	1-2.5μm Ra	1-2.5μm Ra	0.96µm Ra	4.6-6.0µm Ra	3.5-4 µm Ra
Benefits	Reduced porosity and a faster process than the cold chamber die casting	Resolved corrosion problems and extended operating life by minimizing the contact time	Absolute strength and accuracy	Produce low-cost, small-series components	Produce highly accurate and finely detailed castings
Method	High Pressure Die Casting	High Pressure Die Casting	High Pressure Die Casting	Low Pressure Die Casting	High Pressure Die Casting
Production Time	Shorter	Longer	Shorter	Longer	Longer
Cost	Cost-Effective For High Volume Production	Cost-Effective And Affordable Maintenance Cost	Cost-Effective For High Volume Production	Cheapest Method	Less Expensive Than Die Casting

TEAMSWORLD – A PERFECT OEM DIE CASTING MANUFACTURING PARTNER

What makes Teamsworld unique is our ability to develop innovative and sustainable manufacturing solutions and to react quickly and flexibly, no matter the situation or requirement. Most importantly, we commit to protecting all of your information under nondisclosure agreement. Here is why you should get a free quote today!

• Teamsworld specializes in manufacturing automobile parts, electrochemical parts, and other machinery parts. 

• Being well-equipped with a state-of-the-art machinery collection, Teamsworld possesses 20 sets of die casting machines of renowned brands (like TOSHIBA, UBE, TOYO, and Italpresse). While for precision machining, various CNC machines are also well-performed in our facilities. (like CNC milling, grinding, and others).

• Over the past 20 years, Teamsworld has been producing  over 2 million die casting parts each year and has successfully exported them to their valuable customers in the US, Germany, and many other countries around the globe.

If you have any designs to be realized by the die casting process, feel free to book quick consultation sessions with our experts and get professional advice from material selection to engineering suggestions anytime. . For any further questions and related queries, get in touch with us now. We would gladly help!