The die casting process is melting low melting points metal materials such as zinc and aluminum and then injecting them into the die-casting mold through pressure to cool and solidify them into metal parts. Depending on the material’s melting point, there are two die-casting processes, hot chamber casting, and cold chamber casting, which can be used for highly accurate and efficient metal parts manufacturing in industrial, commercial, and consumer industries. The die-casting process uses a relatively long die life and has advantages in the mass production of complex parts. This article focuses on a few core issues of the die-casting process for those who need to manufacture components to understand the process.
First question; what is die casting?
Die casting is a permanent metal casting process in which molten low melting point metal is poured or pressed into a made steel mold at 0.7 to 700 MPA, cooled, and solidified to obtain a metal casting. The dies used for die casting are specially designed for each project. The primary materials are generally non-ferrous metals such as aluminum, zinc, copper, magnesium, magnesium alloys, lead, tin, and tin-based alloys.
Die casting has two opposite methods: hot chamber and cold chamber. The process used depends mainly on the metal and the type of part. The freezing room is used for metals with high melting points, such as aluminum, copper, brass, or copper alloys. Hot section dies casting is limited to metals that do not melt when heated, such as zinc, lead, and magnesium alloys.
Die-casting molds can be designed with a single cavity, multiple cavities, several different part cavities, etc., or a single unit mold and multiple mold combinations made into clamping molds, depending on the part’s complexity, size, and material. Because the mold has a long life, it can be produced repeatedly, and the claims made have a certain visual appeal. Efficient and economical are its advantages.
Die casting eliminates the need for post-processing and additional molding, even for high-volume production of parts with high precision tolerances and complex shapes. Depending on the part design, the aluminum die-casting process can hold tolerances of +/-.002,” and zinc can hold tolerances of +/-.0005″.
Second question: What types of die-casting processes are available?
The machines mainly distinguish the types of die-casting processes. Currently, there are two primary die-casting machines: a hot chamber and a cold chamber. These two basic types of casting process give birth to different variants: vacuum, extrusion, low pressure, and semi-solid die casting. Other die-casting methods are selected according to the part material, geometry, size, and complexity. The three main types are listed below.
Hot chamber process
The hot chamber process is known as the hot mold or gooseneck casting process. In this process, the plunger and chamber of the injection mechanism are immersed in a molten metal bath in a metal furnace and used for low melting point metals that do not chemically react to the immersed plunger assembly.
When the mold is closed, the plunger retracts and opens the chamber port, allowing molten metal to flow into the chamber. The plunger then seals the port while pushing the molten metal into the cavity through the gooseneck tube and nozzle. After entering the hole, the molten metal is pressed until it solidifies inside the mold. Due to the high pressure, the hot chamber process is much more productive than the cold chamber process. Hot chamber casting is more suitable for working with metals with lower melting points, such as tin, zinc, and alloys.
Cold Chamber Process
In the cold chamber process, molten metal is poured into the injection sleeve or chamber portion of the injection cylinder before being pushed into the mold. Because the sleeve is not heated, this is called the cold chamber process. Since the metal melters are separated, there is no corrosion problem.
The cold chamber process begins when the molten material is transferred from the furnace to the pressurized shot chamber through the casting hole. A hydraulic ram seals the cold chamber port and presses the metal under pressure into the mold cavity. The pressure range is between 30 MPa and 150 MPa.
This process is typically used for high melting point alloys of aluminum, magnesium, and copper, but other metals, including ferrous metals, can also be cast. The molten metal temperature starts at 600°C for aluminum and some magnesium alloys, while copper and iron-based alloys are significantly higher.
Vacuum Die Casting
The vacuum die-casting process is an addition to the two traditional die-casting methods and is most associated with the cold chamber process. A vacuum source removes air and gas trapped in the die cavity before the molten metal enters the hole.
This die-casting type minimizes turbulence and gas inclusions and is beneficial for applications used for post-casting heat treatment.
Some advantages of this casting type include improved mechanical properties, better surface finish, dimensional stability, shorter cycle times, and reduced defects caused by trapped gases. Parts can also be heat treated.
Third question: What are the advantages and disadvantages of die-cast parts?
1. Die-cast parts are durable, dimensionally stable, and can maintain tight tolerances.
2. Die-cast parts are physically stronger than injection-molded parts of the same size.
3. Suitable for producing parts with thin-walled designs.
4. The die-casting process can directly produce a smooth or textured surface, making it easy to carry out secondary operations such as plating.
5. Die-casting parts are beautiful and long-lasting and can also enhance the visual appeal of the overall design of the region.
1. Die-casting parts Due to the unique nature of the process (liquid metal filling speed and unstable flow rate), die-casting parts are easy to produce porosity and, therefore, can not be any heat treatment or welding. If heat treatment is carried out, it will quickly lead to micro defects and surface detachment inside the part, thus affecting the region’s quality.
2. For complex parts with a concave design, it is challenging to use die-casting process.
3. if using high melting points alloys, such as copper and other metal materials, the life of the produced die-cast parts is relatively low.
4. the die-casting process requires a high production rate of die-casting molds and machines, thus leading to a very high upfront cost of the die-casting process, which is unsuitable for small batch parts production.
Fourth question: What products are the die-casting process mainly used to produce?
Die-casting parts can be used in the following fields: automobile manufacturing, internal combustion engine production, motorcycle manufacturing, motor manufacturing, oil pump manufacturing, transmission machinery manufacturing, construction, hardware, equipment, machine tools, ships, aerospace, automobiles, locomotives, electronics, computers, electrical appliances, lamps and so on. To find out if your part suits the die-casting process, please get in touch with [email protected] or leave us a message on our website, and our team will contact you immediately.
Automobile industry: car engine cylinder head, transmission case, clutch case, water pump case, carburetor case, steering housing, etc., are all aluminum alloy die castings.
Communication industry: communication equipment radiator, radiator shell
Consumer goods industry: lamps and lanterns, furniture, kitchenware, home accessories, digital shells, crafts, security products shells, LED lighting (lampshades)
The fifth issue: the primary materials used in the die-casting process
Various alloy materials are used in the die-casting process; they are usually non-ferrous metals and vary significantly in mechanical properties. However, almost all types of applications a manufacturer might need can be met. Die-casting alloys are not only able to withstand high operating temperatures but are also fully recyclable. Also, because of the substantial mechanical properties, the die-casting process has a few limitations when choosing materials. The following are a few of the popular alloys on the market:
AZ91:with good casting properties and strength, used for thin-walled parts with complex shapes, such as automobiles, computer parts, hand tools, sports appliances, and household appliances.
AM50, AM60: with outstanding toughness and energy absorption and good strength and mechanical properties, used for car seats, steering wheels, instrument panels, and car wheels.
AM20: with high toughness and impact strength, used for parts requiring high toughness.
AS41: Good creep resistance at 150 degrees, used for parts subjected to high loads, such as cylinder blocks, crankcases, brake parts, etc.
The traditional die-casting zinc alloys are 2, 3, 5, and 7 alloys; the most widely used currently is the No. 3 zinc alloy.
Aluminum alloy die-casting products are mainly used in electronics, automobiles, motors, home appliances, and some communication industries.
Titanium is an important structural metal; titanium alloy has high strength, good corrosion resistance, heat resistance, and other characteristics and is widely used in various fields. Titanium alloy is mainly used to make aircraft engine compressor parts, followed by structural parts for rockets, missiles, and high-speed aircraft.
Sixth question: What surface treatment processes are available for die-cast parts?
Surface treatment is a process method of artificially forming a surface layer on the surface of the base material with mechanical, physical, and chemical properties different from those of the base body. The purpose of surface treatment is to meet the product’s corrosion resistance, wear resistance, decorative or other special functional requirements. For metal castings, the joint surface treatment methods are mechanical polishing, chemical treatment, surface heat treatment, and spraying of the surface. The surface treatment of die-casting parts mainly involves cleaning, cleaning, deburring, degreasing, and removing oxidation skin from the surface of the workpiece. The main types of surface treatment for die-cast parts are electrophoretic paint, black oxide, powder coating, anodic oxidation, chromate, chromium plating, copper-nickel-tin, cobalt-tin, chemical nickel plating, gold plating, silver plating, polyurethane paint, nickel-free surface treatment, impregnation, Teflon, bright nickel, physical vapor deposition (PVD), etc.
The seventh question: what kind of mold is generally used for the die-casting process
The molds used differ for casting parts and casting processes; the common die-casting molds are generally the following.
1. Ordinary die-casting molds
Ordinary die-casting mold is a relatively simple mold in the process of die-casting. It usually adopts a one-piece structure design, mainly including a cavity, core, and gate system.
2. Complex die-casting mold
This die-casting mold has a complex force state, and the size, shape, and appearance of the parts to be cast have high requirements. Therefore, these molds are generally designed with various materials and structures.
3. Aluminum alloy die-casting mold
Aluminum alloy die-casting mold is specially used to produce aluminum alloy die-casting parts. The design of these molds is mainly based on the aluminum alloy solution’s fluidity, solidification, and heat conduction.
4. Zinc alloy die-casting mold
Zinc alloy die-casting molds are used to produce zinc alloy die-casting parts. When designing these molds, the thickness, density, strength, etc., required for the design of the die-casting parts are fully considered, and the appropriate gate position and gate method are selected according to different situations.
5. Copper alloy die-casting mold
Copper alloy dies casting mold specializes in producing copper alloy die casting parts, which is one of the more common types of die casting molds—copper alloy mold in the design of the main consideration parts shape, performance, and other factors.
6. Cold chamber die-casting mold
Cold chamber die-casting mold refers to a mold in which the solution must be heated and insulated through the liquid metal container during casting and then enter the mold through the gate for casting. It is mainly used to produce aluminum, copper, and magnesium alloy parts of various high-quality requirements.
7. Hot chamber die-casting mold
Hot chamber die-casting mold is also called injection mold. This mold uses liquid metal heating equipment to melt and then inject into the mold for casting—mainly used for producing zinc alloy and aluminum alloy parts.
1. The die-casting process is how most products are produced and manufactured.
2. Society depends on die-casting and its ability to produce high-precision technical equipment.
3. the die-casting process allows for economical and efficient mass production of parts.
4. The article provides a brief overview of the die-casting process, its advantages and disadvantages, the materials used, the areas of application, and the dies used through seven questions.
Elimold’s Die Casting Service
The die-casting process is a viral and commonly used necessary manufacturing process. Its popularity is due to its low cost and high efficiency, the simplicity of the production process, and the high quality of the parts produced. The expertise required is relatively low compared to other methods. Therefore, it is more appropriate to outsource this business.
If you choose Elimold to serve you, you will not only have access to engineers and production teams with extensive experience in the die-casting process, but you can also communicate with us about processes such as 3d printing, injection molding, rapid prototyping, cnc machining, sheet metal fabrication, etc.
We are an ISO 9001:2015 certified company with several state-of-the-art manufacturing facilities. Our internal management system is continuously optimized to create a service system that allows for the fastest delivery times and quality of parts. Contact us now for a quote and DfM analysis within 12 hours.