Aluminum casting & mold design services

Introduction

In recent years, the demand for aluminum castings, a technology for manufacturing products by melting aluminum alloy, pouring it into a mold, and solidifying it, has been steadily increasing worldwide, driven by the EV shift and growing lightweighting needs in the automotive industry, as well as the expansion of the electronics sector.
According to a report by Grand View Research, the global aluminum casting market reached approximately $70 billion in 2023 and is projected to exceed $100 billion by 2030. This market expansion represents new business opportunities for Japanese manufacturers, but at the same time, it necessitates a renewed recognition of the significant impact that aluminum mold troubles have on business continuity, cost, and quality.

Molds are critical production equipment that directly influence product quality and productivity, with their associated costs generally accounting for 10% to 30% of product manufacturing costs. However, under the harsh conditions of the aluminum casting process, various problems such as mold wear, thermal cracking, erosion, deformation, and damage are unavoidable. These problems directly lead to tangible losses such as production stoppages, delivery delays, defective products, and unexpected cost increases. The average duration of production stoppages due to mold troubles often ranges from several hours to several days, and in the worst cases, can even cause large-scale line shutdowns lasting several weeks.

This article delves into the root causes of common problems in aluminum molds and provides a detailed explanation of the latest countermeasure technologies to prevent them. Furthermore, it clarifies the specific risks of mold troubles in overseas procurement and introduces how the high-quality solutions provided by Daiwa Aluminum Vietnam can be a reliable partner for Japanese manufacturers. We hope this article will assist your company in resolving mold troubles and improving productivity.

Major Aluminum Mold Troubles and Their Causes

Aluminum casting molds are exposed to extremely harsh environments due to repeated injections of molten aluminum alloy. This makes them prone to various problems, and understanding their types and causes is the first step towards countermeasures. The lifespan of a die-casting mold is generally tens of thousands to hundreds of thousands of shots, but it varies significantly depending on the frequency and severity of problems.

Wear

Wear is one of the most frequent phenomena among mold troubles. It occurs when the high-speed flow of molten aluminum physically erodes the mold surface. It is particularly common in the gate area where molten metal first flows into the mold, the runner area which is the flow path, and the cavity area which forms the product shape. Oxides and other inclusions in the molten aluminum act like abrasives, scraping away the mold surface, which is a major cause of “abrasive wear.“ This process accelerates if the mold surface hardness is insufficient or if surface treatment is inadequate. As wear progresses, product dimensional accuracy decreases, leading to the formation of burrs, unnecessary protrusions, and ejection failures.

Thermal Cracking, Heat Cracking,

Thermal cracking, heat cracking, is caused by repeated thermal stress resulting from rapid temperature changes experienced by the mold during the casting cycle. When molten aluminum is injected, the mold surface is rapidly heated, and then cooled during ejection, a cycle that repeats. This temperature difference causes alternating tensile and compressive stresses on the mold surface, leading to metal fatigue, thermal fatigue,. Micro-cracks appear on the mold surface, gradually grow, and eventually transfer to the product. Thermal cracking has been reported to occur after several thousand shots, depending on the material and casting conditions, and is a major factor affecting mold life. It tends to occur particularly in areas with abrupt changes in wall thickness or at edges.

Erosion

Erosion occurs when molten aluminum and mold material chemically react or when high-temperature aluminum erodes the mold surface. This is particularly prominent in high-pressure die casting, a casting method where molten metal is filled into a mold under high pressure,. Iron and other alloy components in the molten aluminum react with iron on the mold surface, forming intermetallic compounds, e.g., Fe-Al compounds, which embrittle and dissolve the mold surface, leading to defects. This phenomenon progresses more easily as the mold surface temperature is higher and the residence time of molten aluminum is longer. The reduction in mold life due to erosion is said to be as high as over 30%. Erosion severely damages the surface quality of products and directly leads to defective products.

Deformation

Deformation is primarily caused by creep phenomena, the phenomenon where materials plastically deform over time at high temperatures, when the mold is exposed to high temperatures for extended periods, or by concentrated thermal stress resulting from uneven cooling. If the temperature distribution inside the mold is uneven, differences in thermal expansion and contraction occur, which accumulate to distort the entire mold or cause specific parts to bulge. This can lead to inaccuracies in product dimensional accuracy or ejection failures. It is particularly common in large or complex molds and negatively affects product assemblability and function.

Damage

Damage is the final stage of mold trouble, occurring due to a combination of progressive fatigue fracture, excessive stress loads, design flaws, or insufficient maintenance. Stress concentrates in areas where thermal cracks or wear have progressed, ultimately leading to a part of the mold chipping off or the entire mold fracturing. In particular, overlooking stress concentration points during the mold design stage, inappropriate setting of casting conditions, or incorrect choice of mold materials can lead to early damage. Damage means the mold is unusable, causing long-term production line stoppages and enormous costs for mold re-manufacturing.

Latest Countermeasure Technologies to Prevent Troubles

While some aspects of aluminum mold troubles are unavoidable, their occurrence can be significantly suppressed, and mold life extended, by implementing the latest technologies and appropriate management. Below, we introduce specific countermeasure technologies.

Mold Material Choice

The choice of mold material is fundamental to trouble countermeasures. The use of new materials with excellent high-temperature strength, thermal crack resistance, and erosion resistance is essential. In addition to conventional SKD61, a type of hot work tool steel, its improved versions and maraging steel, a type of age-hardening steel that combines high strength and high toughness, are attracting attention. These materials are expected to improve thermal fatigue properties and high-temperature strength, thereby delaying the occurrence of thermal cracks and extending mold life. For example, improved SKD61 can increase thermal crack life by 1.5 to 2 times compared to conventional SKD61. Materials with specific alloying elements added to enhance erosion resistance have also been developed.

Surface Treatment Technology

Applying special treatment to the mold surface can significantly improve wear resistance, thermal crack resistance, erosion resistance, and release properties. Representative technologies include the following:

• PVD/CVD Coating, Physical Vapor Deposition/Chemical Vapor Deposition,: Hard films such as TiN, titanium nitride, TiCN, titanium carbonitride, and CrN, chromium nitride, are formed. This increases the hardness of the mold surface to over Hv 1000, suppressing wear and erosion by molten aluminum. PVD/CVD coatings have been reported to extend mold life by 1.5 to 3 times. The film thickness is typically a few μm, micrometers, but its effect is enormous.
• Nitriding Treatment: Nitrogen is diffused into the mold surface to form a hardened layer. This improves surface hardness and fatigue resistance, suppressing the occurrence of thermal cracks. The treatment temperature is around 500°C, forming a hardened layer with a depth of 0.1 to 0.5 mm.
• TD Treatment, Toyota Diffusion Process,: Carbides are formed on the mold surface, imparting extremely high hardness and erosion resistance. It is particularly effective for erosion countermeasures due to its low reactivity with aluminum. The treatment temperature is 800-1000°C, and the film thickness is about 5-15 μm.

Mold Design Optimization

Ingenuity at the mold design stage is extremely important for preventing troubles. In recent years, the use of CAE analysis, Computer Aided Engineering, has become indispensable.

• Fluid Analysis: Simulates the filling pattern of molten aluminum to design optimal gate positions and runner shapes that prevent misruns and air traps. This is expected to improve the defect rate by several percent.
• Thermal Stress Analysis: Predicts the temperature distribution inside the mold during the casting cycle and the stresses generated by it. This allows for identifying stress concentration points and making design changes, such as adjusting wall thickness or adding radii, to alleviate stress concentration. There are cases where mold temperature was controlled within ±5°C by optimizing cooling channel placement for uniform cooling.

Appropriate Heat Treatment

Applying appropriate heat treatment to mold materials is essential for removing internal stresses, stabilizing the microstructure, and achieving desired hardness and toughness. Precisely managing processes such as quenching, tempering, and sub-zero treatment, cooling to temperatures below 0°C, maximizes the potential performance of mold materials and enhances resistance to thermal cracking and deformation. Inappropriate heat treatment processes can leave residual stresses within the mold, leading to early problems. In particular, the choice of tempering temperature is crucial for determining the balance between mold hardness and toughness, typically performed in the range of 550-650°C.

Cooling System Optimization

The cooling efficiency inside the mold significantly affects casting cycle time and mold life. Particularly noteworthy is conformal cooling, which uses 3D printing, additive manufacturing technology, to form optimized cooling water channels inside the mold. This allows for the placement of cooling channels along the product shape, enabling complex cooling paths that were impossible with conventional drilling. The introduction of conformal cooling not only uniformizes the temperature distribution on the mold surface and reduces thermal stress but also has a proven track record of shortening cooling time by 15% to 30%, contributing to productivity improvement. There are cases where this has reduced cycle time by an average of 10 seconds, increasing annual production by over 10%.

Maintenance and Repair

To minimize mold troubles, thorough regular inspection and early detection/repair are crucial. In addition to visual inspection, introducing non-destructive testing, ultrasonic testing, penetrant testing, etc., can detect micro-cracks and defects invisible from the surface. For repair techniques, laser cladding repair and TIG welding, tungsten inert gas welding, are effective. By using these technologies, worn or damaged parts can be precisely repaired, extending the mold’s lifespan. With appropriate repair, mold life can be extended by tens of thousands of shots. Regular mold cleaning and proper application of release agents also contribute to trouble prevention.

Risks of Mold Troubles in Overseas Procurement and Strengths of Daiwa Aluminum Vietnam

Against the backdrop of pursuing cost competitiveness and diversifying supply chains, overseas mold procurement, especially from the Asian region, has become an important option for Japanese manufacturers. However, overseas procurement entails unique risks not present in domestic procurement, which can increase the probability of mold troubles.

Specific Risks of Overseas Procurement

• Language and Cultural Barriers: Communication gaps and misunderstandings can easily arise, making it difficult to align specifications and share information quickly when problems occur. This risks inaccurate transmission of design change instructions or prolonged time for root cause analysis of quality issues.
• Variations in Technical Levels: The technical levels of overseas suppliers vary, and some may not meet the strict quality standards required by Japan. Differences in experience and know-how, especially in mold design and heat treatment technology, directly impact quality. Some overseas suppliers have reported mold lifespans less than half that of domestic products.
• Differences in Quality Standards: Quality perceptions and standards can differ between Japan and overseas, posing a risk of receiving products that do not meet expected quality levels. Some surveys indicate that the incidence of quality problems in overseas procurement tends to be 5% to 10% higher compared to domestic procurement.
• Challenges in After-Sales Support: Rapid dispatch of technicians to the site in case of problems or an insufficient supply system for repair parts may occur. This can prolong production stoppages and increase opportunity losses.
• Transportation Time and Cost: Due to geographical distance, mold transportation takes time, potentially delaying emergency responses. Transportation costs must also be considered. Air freight significantly increases costs, while sea freight can take several weeks.

These risks, when mold troubles occur, can lead to prolonged production stoppages and additional costs, potentially offsetting the benefits of overseas procurement.

Strengths of Daiwa Aluminum Vietnam

Daiwa Aluminum Vietnam understands these risks in overseas procurement and possesses unique strengths to provide peace of mind and reliability to Japanese manufacturers.

Strict Quality Control Compliant with Japanese Quality Standards

Daiwa Aluminum Vietnam has introduced the technology and know-how cultivated by its Japanese parent company into its production base in Vietnam, establishing a strict quality control system. Experienced Japanese engineers are permanently stationed to guide local staff, ensuring that mold design, manufacturing, and inspection meet the high quality standards required by Japanese manufacturers. Our target defect rate is 0.5% or less, which is comparable to top-level quality standards in Japan. We are also ISO 9001 certified, demonstrating that our quality management system conforms to international standards.

On-Time Delivery and Cost Competitiveness

Vietnam is one of the ASEAN regions experiencing remarkable economic growth and boasts an abundant supply of skilled labor. Daiwa Aluminum Vietnam leverages this geographical advantage to provide high-quality molds at appropriate costs, backed by a stable production system and competitive labor costs, approximately 1/3 to 1/5 compared to Japan. This allows customers to enjoy cost benefits without sacrificing quality and to plan stable production with on-time delivery. Over the past five years, our average on-time delivery rate has been maintained at over 98%.

Prompt Response in Case of Troubles

Even if mold troubles occur, Daiwa Aluminum Vietnam responds quickly and accurately. Japanese staff permanently stationed locally provide meticulous support without language barriers with customers. For technical issues, engineers with extensive experience and knowledge provide consistent support from root cause analysis to countermeasures, striving to minimize production line downtime. We aim to initiate initial response within 24 hours of trouble occurrence and propose concrete countermeasures within 72 hours.

Integrated System for Design, Manufacturing, and Maintenance

Daiwa Aluminum Vietnam has established a system that can provide total support from mold design and manufacturing to post-delivery maintenance. We design optimal molds according to customer product specifications and production conditions, and manufacture them with the latest equipment and technology. Furthermore, we contribute to maximizing mold life and improving productivity by offering services tailored to customer needs for mold trouble countermeasures, such as surface treatment, cooling system optimization, and regular maintenance and repair. We manufacture approximately 150 molds annually and also handle their subsequent maintenance.

Conclusion

Problems such as wear, deformation, and damage in aluminum casting molds are unavoidable challenges in the casting process, and they represent significant issues for Japanese manufacturers, directly impacting productivity, quality, and cost. However, by implementing the latest countermeasure technologies introduced in this article, such as mold material choice, surface treatment technology, mold design optimization, appropriate heat treatment, cooling system optimization, and continuous maintenance and repair, these risks can be minimized, and mold life can be significantly extended.

Especially when considering overseas procurement, there are specific risks such as language and cultural barriers, variations in technical levels, and differences in quality standards. To overcome these risks and stably procure high-quality aluminum casting molds, choosing a reliable partner is essential.

Daiwa Aluminum Vietnam has introduced the technology cultivated by its Japanese parent company and a strict quality control system into its production base in Vietnam, providing high-quality molds and aluminum casting products that Japanese manufacturers demand. Through meticulous support by experienced Japanese engineers, a cost-competitive production system, and integrated services from design to manufacturing and maintenance, we contribute to solving our customers’ mold troubles and improving productivity.

To management and procurement managers facing mold troubles, please consult Daiwa Aluminum Vietnam. We promise to be a reliable partner that strongly supports the success of your business.