Aluminum casting & mold design services

Introduction

For Japanese manufacturing to succeed in global competition, improving product quality and reducing costs are perpetual challenges. Especially with the increasing demand for lightweighting in many sectors, including the automotive industry, the importance of aluminum die-cast parts continues to grow. However, as executives and procurement managers are well aware, “mold design“ significantly influences product quality and production efficiency. This article delves into how maximizing precision and durability in aluminum die casting mold design impacts product quality, production costs, and delivery times, and introduces the value of high-precision, high-durability mold design offered by Daiwa Aluminum Vietnam.

The global aluminum die casting market reached approximately $75 billion, about 11 trillion JPY, in 2023 and is projected to grow to about $110 billion, about 16 trillion JPY, by 2030. This growth is driven by the increasing demand for large, complex-shaped parts such as vehicle bodies and battery cases, accompanying the shift to electric vehicles, EVs,. The adoption rate of aluminum die casting in automotive parts is expected to further increase with the advancement of EVs, with estimates suggesting that EVs use approximately 30% more aluminum parts on average compared to internal combustion engine vehicles, Source: Global Information, Society of Automotive Engineers of Japan,. In such a market environment, it is no exaggeration to say that the superiority of mold design determines a company’s competitiveness.

Mechanism by which Mold Design Determines the Precision and Durability of Aluminum Die-Cast Products

The quality of aluminum die-cast products is largely determined at the mold design stage. Specifically, the following factors significantly impact product precision, durability, and the lifespan of the mold itself.

Cavity Design and Molten Metal Flow Analysis

The design of the cavity, the space that forms the product shape, directly affects the behavior of molten aluminum as it fills the mold. Inadequate design can lead to casting defects such as incomplete filling, shrinkage porosity, depressions on the product surface, and entrapment defects, air or gas trapped inside the product, severely compromising product strength and appearance. By using the latest CAE, Computer Aided Engineering, analysis, especially molten metal flow analysis, fluid analysis, it is possible to simulate molten metal filling patterns, pressure distribution, and temperature changes at the design stage to derive the optimal cavity shape. This has been reported to reduce defect rates by up to 20%, Source: JSOL Corporation,.

Cooling System Design

The cooling system within the mold has a decisive impact on product dimensional accuracy, crystal structure, and the thermal stress, stress due to thermal expansion and contraction, of the mold itself. Uneven cooling can cause product deformation and residual stress, reducing dimensional accuracy. Furthermore, repeated excessive thermal stress on the mold can lead to mold cracking and heat checking, micro-cracks due to thermal fatigue, significantly shortening mold life. Proper cooling system design has been shown to improve mold life by over 30%, Source: Japan Die Casting Association,. The position, diameter, flow path design of cooling channels, and the flow rate and temperature control of the coolant are extremely important.

Gate and Runner Design

The design of the gate, the part where molten metal flows into the cavity, and the runner, the passage that guides molten metal to the gate, is essential for stable molten metal supply and uniform product quality. If the gate size or shape, or the runner cross-section or arrangement, is inappropriate, the molten metal can become turbulent, leading to air entrapment and temperature variations. This can result in variations in the product’s mechanical properties or damage to the surface quality. Optimal gate and runner design ensures smooth and uniform filling of the cavity with molten metal, enhancing overall product quality.

Draft Angle and Undercuts

The draft angle, the taper required to remove the product from the mold, directly affects the product’s demoldability, ease of removal from the mold,. Insufficient draft can cause the product to stick to the mold, leading to demolding failures, product damage, and even wear and scratches on the mold surface. Generally, a draft angle of 1 to 3 degrees is recommended for aluminum die casting, Source: Misumi Corporation,. Undercuts, shapes that cannot be removed in the opening direction of the mold, require complex mechanisms such as slide cores, complicating the mold structure and increasing manufacturing and maintenance costs. Efforts are needed to avoid undercuts as much as possible or minimize them at the design stage.

Material Choice and Surface Treatment

The material used for the mold determines its heat resistance, wear resistance, and toughness. Hot work tool steels such as SKD61 are commonly used, but for more severe conditions, high-nickel alloy steels and powder high-speed steels may also be considered. Material choice can improve heat resistance, for example, from approximately 550°C for SKD61 to over 600°C for special alloy steels. Furthermore, the treatment applied to the mold surface significantly affects mold life and product demoldability. Nitriding, PVD, Physical Vapor Deposition,/CVD, Chemical Vapor Deposition, coatings, and TD treatment, Thermal Diffusion Penetration Treatment, are typical examples, which increase the surface hardness of the mold to approximately HV800-2000, improving wear resistance and heat checking resistance, Source: Japan Surface Finishing Association,.

Specific Approaches to Mold Design for Maximizing Precision and Durability

To design high-precision, high-durability molds, an integrated approach combining multiple elements, not just a single technology, is essential.

Utilization of CAE Analysis, Molten Metal Flow Analysis, Thermal Stress Analysis,

CAE analysis is an indispensable tool in modern mold design. Molten metal flow analysis accurately predicts the filling behavior of molten metal, identifying potential risks of defects such as incomplete filling, entrapment, and shrinkage porosity in advance. This allows for optimization of gate positions, runner shapes, and vent, air vent, placements at the early design stage. Thermal stress analysis predicts temperature distribution within the mold and stress concentration points due to thermal expansion and contraction, reducing the risk of mold cracking and heat checking. Introducing CAE analysis has been shown to reduce mold development time by an average of 25% and reduce the number of prototypes from three to one, Source: JSOL Corporation,.

Mold Material Choice and Heat Treatment Technology

The choice of mold material varies depending on the required product quality and production volume. Hot work tool steels with high strength and toughness, e.g., SKD61, H13, offer excellent heat resistance and wear resistance. Furthermore, appropriate heat treatment, quenching and tempering, maximizes the inherent performance of the material, improving the mold’s hardness, toughness, and thermal fatigue resistance. For example, vacuum heat treatment and sub-zero treatment, cryogenic treatment, have the effect of refining the material’s microstructure and extending mold life.

Evolution of Surface Treatment Technology

Mold surface treatment technology is constantly evolving, dramatically improving the mold’s wear resistance, heat checking resistance, and demoldability. PVD/CVD coatings, e.g., TiN, CrN, TiAlN, form a hard, thin film on the mold surface, suppressing wear and erosion, corrosion by molten metal,. This often extends mold life by 2 to 5 times, Source: Japan Surface Finishing Association,. Nitriding is a treatment that diffuses nitrogen into the mold surface to increase hardness, and it is relatively inexpensive and widely applicable. These surface treatments are also expected to improve product demoldability and reduce the amount of release agent used.

Optimization of Cooling Structure

Uniform cooling is key to stabilizing product quality and extending mold life. In addition to conventional linear cooling channels, “conformal cooling“ has recently attracted attention. This is a technology that uses 3D printing, additive manufacturing, to directly form complex cooling water channels inside the mold along the product shape. This equalizes the temperature distribution throughout the mold and eliminates hot spots, localized high-temperature areas,. The introduction of conformal cooling has been reported to reduce cycle time by up to 15% and improve product dimensional accuracy by 20%, Source: Sodick Co., Ltd.,.

Maintainability and Replaceable Parts Design

Molds are consumables, and regular maintenance is essential. By modularizing wear-prone parts, e.g., slide cores, ejector pins, and designing them for easy replacement at the design stage, maintenance time can be shortened and downtime reduced. Furthermore, standardizing mold parts can reduce the procurement cost of replacement parts. Proper maintenance planning and easy part replacement extend the overall mold life and optimize production costs.

Strengths of High-Precision, High-Durability Mold Design at Daiwa Aluminum Vietnam

When Japanese manufacturers consider overseas procurement, quality, cost, delivery time, and stable supply are crucial decision criteria. Daiwa Aluminum Vietnam, Daiwa Light Alloy Industry Vietnam, leverages its unique strengths in high-precision, high-durability aluminum die casting mold design and manufacturing to meet these needs.

• Design and Manufacturing System Based on Japanese Quality Standards: Daiwa Aluminum Vietnam has introduced the mold design and manufacturing know-how and quality control standards cultivated over many years by its Japanese parent company to its Vietnamese base. This enables the stable supply of high-quality molds equivalent to those in Japan. Over the past 10 years, we have designed over 200 molds for various fields, including automotive parts, electronic device parts, and medical device parts, maintaining a defect rate of less than 0.5%.
• Design by Latest CAE Analysis Software and Skilled Engineers: We utilize state-of-the-art molten metal flow analysis and thermal stress analysis software to thoroughly conduct virtual verification at the design stage. This minimizes the risk of casting defects and achieves designs that maximize mold life. Our engineers receive regular training from Japanese experts, constantly acquiring the latest technologies and knowledge.
• Cost Competitiveness and Stable Supply System in Vietnam: Vietnam is experiencing remarkable growth in manufacturing, particularly within the ASEAN region, offering high competitiveness in labor costs and manufacturing expenses. Daiwa Aluminum Vietnam, Daiwa Light Alloy Industry Vietnam, leverages this geographical advantage to provide high-quality molds with cost benefits. We have also established a stable workforce and supply chain, enabling flexible responses to sudden increases in production or specification changes. Currently, we have business relationships with over 50 Japanese companies, building long-term partnerships (Source: Japan External Trade Organization, JETRO,).
• Flexibility to Handle Everything from Small-Lot Multi-Product Production to Mass Production: Customer needs are diverse. We propose optimal mold solutions tailored to customer production plans, from molds for small-lot production at the prototyping stage to molds for mass production capable of withstanding millions of shots. By promoting standardization of mold parts and modular design, we also achieve short delivery times.
• Optimal Mold Solution Proposals Tailored to Customer Needs: We don’t just manufacture molds; we participate from the customer’s product design stage, offering comprehensive solutions such as design reviews considering castability, cost-effective material choice, and optimal surface treatment proposals. This enables customers to shorten development periods and reduce total costs.

Conclusion

Optimizing mold design is essential for improving the quality of aluminum die-cast products, reducing production costs, and enhancing competitiveness. Specifically, mold design that maximizes precision and durability directly leads to improved product yield, extended mold life, and reduced maintenance costs, ultimately contributing significantly to increased corporate profitability. The utilization of CAE analysis, optimal material choice and heat treatment, and the evolution of surface treatment technologies and cooling structure optimization are indispensable elements in modern mold design.

Daiwa Aluminum Vietnam, Daiwa Light Alloy Industry Vietnam, is a reliable partner that combines Japanese quality standards with Vietnamese cost competitiveness to provide high-precision, high-durability aluminum die casting molds to Japanese manufacturers. We constantly incorporate the latest technologies and our skilled engineers propose optimal solutions to meet our customers’ diverse needs. When considering overseas procurement, please consult Daiwa Aluminum Vietnam. We are committed to doing our utmost to contribute to the success of your business.