Introduction
Die casting is a casting technology in which molten aluminum alloy is injected into a mold at high speed and high pressure, then cooled and solidified. Once a mold is created, parts can be formed in a matter of seconds, making it ideal for the mass production of components for automobiles, home appliances, and electronic devices. A major feature of this technology is its ability to produce complex shapes with high dimensional accuracy and a smooth surface finish in a single process.
In particular, aluminum die casting contributes to weight reduction in parts due to its capability for thin-wall casting. This can reduce the overall weight of a product by 20-30%, improving energy efficiency and operational speed. Furthermore, it boasts excellent corrosion resistance and thermal conductivity, which are characteristic of aluminum alloys, ensuring stable performance even under harsh operating conditions. Aluminum is also highly recyclable, contributing to a lower environmental impact through the collection and re-melting of scrap.
These advantages address the manufacturing industry’s need to balance cost reduction with quality maintenance and functional improvement. At Daiwa Keikinzoku Vietnam, we achieve a 20-30% reduction in manufacturing costs compared to domestic production in Japan and have shortened transportation costs and lead times by reaching a local procurement rate of 70-80%. Moreover, a JBIC survey (2022, 195 respondents) reported that 97% of companies are considering expanding their investment in Vietnam in the medium to long term.
Sources:
- diecast.co.jp “Die Casting Technology Overview”
- kiyota-and.co.jp “The Basics of Die Casting”
- Daiwa Keikinzoku Vietnam “Explaining the Features and Merits of Aluminum Die Casting”
- protech-japan.jp “Basic Information on Die Casting”
- JBIC “Survey on Medium- to Long-Term Investment Trends in Vietnam (2022)”
Case Studies of Aluminum Die Casting for Automotive Parts
Oil Pans (Cost Competitiveness through Production in Vietnam)
Located at the bottom of the engine, the oil pan is a critical component responsible for storing and circulating lubricating oil. By using aluminum die casting’s integrated molding technology, complex rib shapes and thin-walled parts can be mass-produced in short cycles, significantly reducing the number of processes and material loss compared to machining. At Daiwa Keikinzoku Vietnam, by increasing the local procurement rate to 70-80%, we have suppressed labor and transportation costs, achieving a cost reduction of approximately 20-30% compared to domestic production in Japan.
Condenser Cases for Hybrid Vehicles (Weight Reduction and Improved Thermal Management)
Condenser cases for hybrid vehicles must efficiently dissipate heat while protecting refrigerant lines. By using the highly thermally conductive ADC12 alloy and integrally molding complex cooling fins and thin-walled shapes, the number of parts is reduced, achieving a weight reduction of about 20% compared to assembled steel plate products. This also contributes to improving the vehicle’s fuel efficiency (jfs.or.jp, shinnichikogyo.co.jp).
Corrosion Resistance and Quality Assurance for Large Parts (JIS Compliance Example)
For large cast parts such as suspension components and engine covers, corrosion resistance and dimensional accuracy are essential. By applying pretreatment technology and painting processes developed for marine engines in an integrated production system, we ensure high corrosion resistance. Furthermore, under a quality assurance system certified for compliance with the Japanese Industrial Standards (JIS), we provide highly reliable large parts through strict dimensional tolerance management and a stable supply of mechanical properties.
Case Studies of Aluminum Die Casting for Home Appliances
Juicer and Mixer Housings (Artistic Appeal and Mass Producibility)
For the exterior housings of household juicers and mixers, balancing “aesthetic appeal” and “mass producibility” is a major challenge. Aluminum die casting allows for the integral molding of smooth curves and sharp edges, making it possible to reproduce complex designs with just the mold. A thin-wall design with a thickness of 1.5 mm reduces the product weight by about 20% compared to conventional methods while securing the necessary rigidity. Additionally, a shot blasting and anodizing process creates a high-end matte surface finish, and stable supply is possible with a production line of 100,000 units per month.
Cordless Vacuum Cleaner Main Frames (Thinning and Securing Rigidity)
The frames of cordless vacuum cleaners require light weight and good handling. In one case, by adopting a die-cast part with a wall thickness of 1.2 mm, a weight reduction of about 15% was achieved compared to a plastic housing. While making the part thinner, the optimal placement of ribs that do not compromise bending rigidity allowed it to pass drop tests from a height of 1.5 m onto the floor and repeated impact tests. Such thin-wall forming is a specialty of die casting, making it possible to obtain high strength while suppressing increases in manufacturing costs.
LED Lighting Fixture Cases (Heat Dissipation and Design)
For interior LED lighting fixtures, both heat dissipation performance and design must be achieved. In Panasonic’s track-mounted model XAS1531N, an aluminum die-cast shade made of ADC12 alloy is used to achieve a luminous flux of 400 lm, a power consumption efficiency of 97.5 lm/W, and a color rendering index of Ra90. By integrally molding fin-like ribs on the back of the shade, the heat dissipation area is increased by about 30%, suppressing the temperature rise of the LED elements. As a result, a long lifespan of over 20,000 hours and uniform optical characteristics are achieved simultaneously.
Sources:
- Kiyota Co., Ltd. “What is Aluminum Die Casting | Explaining Features and Manufacturing Processes”
- Japan Ferrous & Non-Ferrous Metal Scrap Association “Q&A Case (2) Non-Ferrous | The Straight Answer… Things You Couldn’t Ask Before”
- Panasonic “XAS1531N | Lighting Fixture Search”
Case Studies of Aluminum Die Casting for Electronic Device Parts
Electronic device parts are required to simultaneously meet the demands of precision, mass producibility, and high heat dissipation. Since aluminum die casting can form parts with all these features in one go, it is widely used in everything from office automation equipment and communication devices to IoT terminals. Below are representative examples by application.
Thin Laptop PC Chassis (Fanless Heat Dissipation Design)
For thinning down laptops, a fanless design that allows the chassis itself to function as a heat sink is effective. By leveraging the thermal conductivity of ADC12 alloy to integrally mold a 300x200x15mm chassis with a wall thickness of 1.5mm, the heat dissipation area is expanded by 30% compared to conventional designs, reducing the average CPU temperature by 10°C. Furthermore, a blast treatment and anodized finish ensure a surface roughness of Ra1.6μm or less, achieving both high heat dissipation performance and excellent appearance quality.
Housing for Current Measurement (30% Cost Reduction by Changing Method)
For a 180x170x60mm current measurement housing that was switched from conventional sand casting to a patented die-casting method, a dimensional accuracy of CT6 grade and a surface roughness of Ra12.5μm were achieved. The introduction of a die-cast cassette system reduced mold costs by 50%, leading to a 30% reduction in total cost. In addition, the manufacturing lead time was halved, ensuring profitability even for small-lot production of 400 units per year.
Smartphone Rear Covers (High-Precision Surface Finish)
Rear covers must be thin and have a high-end feel. A model achieving a wall thickness of 0.8mm with ADC12 alloy weighs only about 15g and can be molded with CT6 grade accuracy and a tolerance of ±0.1mm. After injection, barrel polishing and chemical conversion coating are applied to reproduce a mirror-like finish with a surface roughness of Ra0.8μm or less in a single process. This maintains stable, high quality even in mass production of tens of thousands of units.
Sources:
- mitsu-ri.net “What is Die Casting? Product Examples, Merits/Demerits, and Differences from Forging”
- Taikennet “Case Studies of Aluminum Die Casting for Electronic Devices”
- Precision Housing & Frame Factory “Basic Knowledge of Aluminum Housings ①”
- Taiyo Parts “Cases for Electronic Devices – Die Casting Cost Down Navi”
- Taiyo Parts “About Smartphone Manufacturing Supported by Die Casting”
Quality Control and Defect Countermeasures
Methods for Reducing Porosity and Shrinkage Porosity
Among casting defects, gas porosity and shrinkage porosity can lead to reduced part strength and oil leaks, so their thorough suppression is necessary. Gas porosity occurs when nitrogen and oxygen in the molten metal become trapped in the mold. Effective countermeasures include degassing treatments using nitrogen purging or argon blowing, the introduction of vacuum casting, and the optimal design of mold vents. Since shrinkage porosity is caused by volume reduction during solidification, it can be suppressed by optimizing the reservoir design, adjusting the injection weight, and controlling the cooling rate (5–15 °C/s) to sufficiently fill the mold cavity.
Surface Roughness and Dimensional Accuracy Control Flow
Surface roughness is targeted at Ra1.6–6.3 μm depending on the application, and deterioration is mainly caused by mold wear and insufficient venting. A stable finish is maintained by combining regular mold polishing, inspection of vents and cooling channels, and post-molding shot blasting or barrel polishing. For dimensional accuracy, key points include mold design that anticipates cooling shrinkage (e.g., 100 mm shrinks to approx. 98 mm, a reduction of about 2%) using CAE simulation, as well as standardizing injection pressure, molten metal temperature, and cooling time (30–60 second cycle). During production, in-line measurements are taken with calipers, micrometers, and CMMs, and if abnormalities are detected, parameters are adjusted immediately to minimize variations.
Use of Statistical Process Control (SPC) and Non-Destructive Testing
In SPC, key data such as injection pressure, molten metal temperature, and cooling rate are monitored with control charts to maintain process capability indices (Cp, Cpk). When an abnormal value is detected, an alarm is triggered, and the mold temperature or injection speed is automatically corrected. In addition, by combining non-destructive tests such as radiography (X-ray: 100–400 kV), ultrasonic testing (2–10 MHz), and eddy current testing, internal defects can be detected without damage, preventing a decline in yield. By operating these systems in an integrated manner, a stable supply of high-quality aluminum die-cast parts can be achieved.
Sustainability and Recycling
Aluminum Recycling Rate and CO₂ Reduction Effects
In Japan, the recycling rate for aluminum beverage cans reached 99.8% in fiscal year 2024, with 75.7% of that being recycled back into can material. This shows that aluminum as a resource is being recovered and regenerated with high efficiency. Globally, about 75% of all aluminum ever produced has been recycled, and much of it is still in use as products today. In addition, using aluminum derived from scrap reduces the required energy to about 5% compared to primary production, and CO₂ emissions can be cut by 92-95%. This data indicates a significant contribution to the reduction of greenhouse gas emissions across the manufacturing industry.
ESG Compliance in the Supply Chain
In recent years, participation in the “Aluminium Stewardship Initiative (ASI)” has been growing in the aluminum industry, strengthening responsible sourcing and decarbonization throughout the supply chain. A joint initiative promoted by Marubeni and Rio Tinto is establishing a system where customer companies can procure responsible aluminum products stably over the long term. Additionally, UACJ obtained ASI certification in 2022 and is collaborating with over 360 companies and organizations to develop and audit traceability standards and GHG reduction targets. Furthermore, the International Aluminium Institute (IAI) announced a new greenhouse gas reduction reporting initiative at COP28, making the industry’s environmental impact reduction more transparent and mandatory. These efforts support the improvement of ESG ratings and the acquisition of green procurement certifications for sourcing companies, leading to increased trust from end-product users.
Sources:
- Aluminum Can Recycling Association “Recycling Rate – Aluminum Can Recycling Association”
- Aluminum Association “Sustainability – Recycling”
- European Circular Economy Platform “Metal Recycling Factsheet”
- Marubeni & Rio Tinto “Building a Sustainable and Responsible Aluminum Product Supply Chain”
- UACJ “Sustainability Management: Global Aluminum …”
- International Aluminium Institute “Aluminium industry backs new greenhouse gas initiative”
Conclusion
Key Points on Implementation Effects from Case Studies For automotive parts, local production at our Vietnam base achieved a 20-30% cost reduction, while thin-wall technology improved the rigidity and thermal management performance of components. For home appliances, we have faithfully reproduced complex designs through integrated mold forming and established a system for the stable supply of 100,000 units per month. For electronic device parts, we have adopted fanless heat dissipation designs and mirror finishes, enhancing product durability and usability.
Future Market Outlook and Points to Consider When Selecting a Supplier As US-China tensions prolong and supply chain restructuring progresses, diversifying procurement sources away from a reliance on China to places like Vietnam is essential. Furthermore, it is required to select suppliers based on their response to international initiatives like ASI certification and an evaluation of their 92-95% CO₂ emission reduction through the use of scrap-derived aluminum, focusing on traceability and a high recycling rate.
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