Aluminum die casting is a high-pressure process that forms complex, precise parts by injecting molten aluminum into a steel mold. Compared with methods such as sand casting or gravity casting, it has faster molding cycles, higher dimensional accuracy, and better surface finish. Its performance depends on several key aspects, including die casting mold design, alloy smelting, and die casting parameter control, among others.
This article will explore why aluminum alloys are the preferred material for die casting, analyze each key stage in the aluminum die casting process, explain its design points, core advantages, and list typical applications of aluminium die casting products in various industries. Read on to learn more.
Why Aluminum Alloys
Aluminum alloys are very suitable for the high-pressure die casting process due to their light weight, high strength, excellent thermal and electrical conductivity, and good castability.
The addition of silicon, copper, and magnesium elements to the alloy improves fluidity and mechanical properties, which is conducive to the one-time molding of complex structures.
Its strong corrosion resistance makes it suitable for industries such as automobiles and electronics that require high environmental stability.
Aluminum alloys also have good machinability and recyclability, which is in line with the trend of sustainable manufacturing and has become the preferred material for modern die castings.
Key Stages of Aluminum Die Casting
Mold Design
The mold is made of high-strength mold steel, generally made of H13 or SKD61. Preheating the mold can prevent thermal cracks, improve the fluidity of molten aluminum, and reduce incomplete filling.
The mold surface is usually coated with a high-temperature resistant coating, which can reduce wear, reduce mold sticking, extend mold life, and reduce maintenance frequency.
Alloy Selection
Different aluminum alloys have different properties and need to be accurately selected according to the product application scenario.
A380 is suitable for general structural parts; A360 has excellent corrosion resistance and is suitable for marine or chemical industries; ADC12 is suitable for aluminium die casting components with complex molding and thin wall thickness.
Melting Control
Aluminum alloys are usually melted at about 660°C. During the process, the content of impurities, gases, and oxides must be strictly controlled to prevent pores, inclusions, and structural defects.
The use of centralized smelting, online degassing, and filtration systems can help improve metal purity and process stability.
Metal Injection
The metal injection process uses high pressure to quickly press molten aluminum into the mold cavity. Filling speed and pressure control are the key to preventing shrinkage, cold shut, and pores.
Precisely matched injection speed and clamping force can help achieve the molding of complex details and thin-walled structures, and improve dimensional accuracy and stability.
Cooling
Reasonable cooling system design determines whether the part will produce deformation or internal stress.
The cooling channels should be evenly laid out to ensure smooth heat conduction and avoid local overheating.
Controlling the solidification sequence can also help optimize the grain structure and improve the mechanical properties and stability of the casting.
Demolding and Trimming
The ejector system should be arranged reasonably to ensure uniform distribution of demolding force and prevent surface scratches. After molding, the flash, gate, and runner should be removed in time.
It is recommended to use automated trimming to ensure dimensional consistency and surface cleanliness. A good demolding design can also reduce production cycles and improve efficiency.
Aluminum Die Casting Design Points
Wall Thickness Design
Thin walls (less than 2mm) may lead to insufficient filling, while thick walls (greater than 5mm) will lead to slow cooling, internal looseness, and waste of material.
It is recommended to keep the wall thickness of the casting between 2.5–3.5mm and try to keep it consistent throughout the structure to avoid shrinkage, deformation, or pores caused by uneven hot and cold.
Transition fillets should be designed between different wall thicknesses to avoid sudden changes in wall thickness.
Draft Angle and Fillet
All surfaces perpendicular to the demolding direction should be designed with a draft angle of 1°–3°, which helps the casting to be demolded smoothly and avoid surface scratches.
It is safer to have a smaller outer wall draft angle (1°) and a slightly larger inner wall draft angle (2°–3°).
The corner position should adopt a fillet transition of R1–R3 to prevent stress concentration, mold cracking, and metal stagnation.
Avoid Undercut Structures
Try to avoid designing undercuts, lateral holes, or inner grooves that require the use of sliders or side cores, which will significantly increase the complexity, cost, and maintenance frequency of the mold.
If undercuts are indeed required, they should be arranged in a centralized manner, the structure should be simplified, and sufficient space for the side core to move should be ensured to avoid mold jamming.
Rib and Boss Design
Bosses are used to connect bolts or pins and should be designed to be hollow (center punched) to prevent shrinkage cracks. The thickness of the rib should be 50%–70% of the thickness of the adjacent main wall.
Too thick will cause uneven cooling, resulting in pores or shrinkage marks. Adding an R angle transition between the rib and the wall can improve metal fluidity and reduce stress concentration.
Hole Position Design
All holes should be opened along the mold parting direction as much as possible to avoid using side cores.
If side cores must be used, ensure that the core pulling direction is smooth and evaluate its impact on mold life and production cycle.
The hole diameter should be slightly larger than the finished product size, considering the die casting shrinkage, and reserve finishing allowance (such as tapping or drilling).
The hole distance edge is recommended to be greater than twice the wall thickness to avoid cracks.
Core Advantages of Aluminum Die Casting
High Precision
Aluminium alloy die casting can achieve a dimensional tolerance within ±0.05 mm, which is suitable for high-precision connectors, assembly structural parts, and thin-walled complex products.
Details such as threaded holes, logos, chamfers, grooves, etc., can be directly formed to reduce machining steps and improve dimensional consistency and assembly efficiency.
Rapid Prototyping
The die casting production cycle is short, and the single mold cycle time is generally between 30 and 60 seconds.
Combined with multi-cavity molds and automated equipment, tens of thousands of castings can be produced in a day, which is suitable for mass production and tight delivery projects.
The mold life is usually more than 50,000 to 200,000 molds, and the amortization cost is low.
Less Post-Processing
The high surface quality and good dimensional repeatability make most die casting parts directly usable, and only local CNC machining is required for threaded holes, sealing surfaces, and other locations.
The post-processing links, such as deburring, tapping, and spraying, are highly automated, which can save more than 30% of processing and labor costs overall.
Structural and Functional Integration
Aluminum die castings have good strength, rigidity, and heat resistance, while being light and having high thermal conductivity.
It can carry mechanical loads and heat dissipation functions at the same time, and is often used in core parts such as engine brackets, thermal management housings, and electronic control modules.
Structural parts and functional parts can be designed in an integrated manner to reduce the number of parts.
Wide Application Range
Aluminum die casting is widely used in many industries such as automobiles, consumer electronics, new energy, communication equipment, industrial automation, medical equipment, aerospace, household appliances, rail transit, LED lighting, power tools, security equipment, robot systems, and heavy machinery.
Common Applications of Die Casting Parts
Automotive Industry
Aluminum die casting is widely used in core components such as gearbox housings, cylinder heads, engine brackets, hub covers, and heat dissipation modules.
It has the advantages of lightweight, high strength, heat resistance, and high dimensional accuracy, and is suitable for electric vehicle power systems, chassis structures, and thermal management units.
Electronics
Used in mobile phone middle frames, notebook bottom shells, tablet shells, connectors, radiators, shielding shells, and other components.
Aluminum die casting has strong thermal conductivity, good shielding performance, and is easy to surface treat, which is suitable for large-scale, light, and high-precision electronic product structure design.
Industrial Equipment
Applied to structures such as motor housings, pump bodies, gearboxes, reducer housings, and servo module frames.
Aluminum die castings can maintain dimensional stability and mechanical properties in high-temperature, oily, and corrosive environments, and are suitable for industrial scenarios with heavy loads and long-term operation.
Communications and 5G Equipment
Used in base station housings, antenna brackets, RF module housings, filter housings, etc, aluminum die casting has excellent thermal conductivity and electromagnetic shielding capabilities.
It enables one-piece molding, improves heat dissipation efficiency and equipment reliability, and meets the needs of 5G high-frequency communication.
Electric Vehicle
Commonly used in battery housings, electronic control unit housings, BMS module structures, charging pile housings, and heat exchange modules.
Aluminum die casting can not only achieve lightweight and thermal management, but also meet the requirements of high-voltage insulation, structural integration, and long-term reliability
LED Lighting System
Commonly used in structures such as lamp housings, heat sinks, drive power housings, and module brackets.
Aluminum die casting has excellent thermal conductivity and a stable structure, which can reduce LED light decay, suppress temperature rise, and improve system stability.
It is widely used in high-power lighting equipment such as street lamps, tunnel lamps, and mining lamps.
Medical Instrument
Applicable to structures such as instrument housings, panel frames, handheld probes, and scanning components.
Aluminum die casting parts are lightweight, corrosion-resistant, highly consistent in size, and easy to clean with a smooth surface, meeting the requirements of medical equipment for high cleanliness, high precision, and structural stability.
Why Choose CEX Casting
In-House Mold Development
The die casting die is completed by the company’s internal team, covering structural design, DFM analysis, mold flow simulation, processing, and debugging.
With fast response and flexible modification capabilities, it can optimize the gate, cooling, demolding, and other structures, greatly improve the mold life and molding efficiency, and shorten the proofing and mass production preparation cycle.
Centralized Smelting of Raw Materials
The cleanliness and chemical composition of aluminum liquid are stably controlled through centralized smelting, online degassing, and filtration systems.
Significantly reducing defects such as pores and slag inclusions, the casting structure is denser and the performance is more stable, which is widely used in high-strength, high-sealing requirements or precision parts that require X-ray inspection.
Patented Squeeze Casting Technology
CEX Casting has a self-developed patented squeeze casting process that can perfectly replace traditional aluminum alloy die casting.
Suitable for aluminum alloy castings with high strength, high density, and high airtightness requirements.
This process can effectively reduce the internal pores and shrinkage cavities of the castings, and the mechanical strength is comparable to that of 5-series or 6-series forged aluminum alloys.
CEX Squeeze Casting Workshop
Strict Quality Control
ISO9001 and IATF16949 certified suppliers meet the factory inspection and certification requirements of high-end European and American customers.
The internal quality inspection laboratory is equipped with equipment such as spectrometers, X-ray machines, three-coordinate machines, tensile testing machines, helium detectors, etc., and quality inspection covers every link from raw materials to finished products.
Conclusion
The basic aspects of the aluminum die casting process, such as mold design, alloy smelting, and casting parameter control, are the core of achieving stable and high-quality production.
Correct application of these points can help improve strength, reduce defects, and reduce overall costs.
As an experienced aluminum die casting manufacturer, CEX Casting provides high-precision, almost zero-defect aluminum alloy squeeze die casting services to meet your customized needs.
Contact us now to get a quote for your exclusive aluminum die casting project.