Die casting

Die casting: expert knowledge on processes, materials & procurement

In modern transportation and environmental technology, where precision, durability and efficiency are not options but basic requirements, high-performance components form the foundation. From robust housings for power electronics in a subway to precise sensor housings in water treatment plants - the requirements are immense. As a technical procurement partner with deep-rooted industrial DNA, we at Trade World One know that choosing the right manufacturing process is crucial to the success of a project. One casting process stands out here due to its unique combination of cost-effectiveness, precision and design freedom particularly emphasized: the Die casting (often also Die casting called).

This technical article sheds light on the die casting process in all its depth. We go beyond the basics and delve into the technical details, material science and application-specific benefits. Our goal is to give you - the engineers, purchasers and project managers - a solid understanding of die casting and how a strategic partner like Trade World One can make the difference between a component and a true die casting solution.

What is die casting? Definition and delimitation of the casting process

At its core, high-pressure die casting (HPDC) is a casting process in which a liquid metal melt is pressed under high pressure (up to over 1,000 bar) and at high speed into a two-part, reusable permanent mold made of steel. Once the metal has solidified, the mold is opened and the finished casting (blank) is ejected. This fundamental process enables the production of parts with high dimensional accuracy, complex geometries and excellent surface quality in very short cycle times, which makes die casting particularly suitable for series production.

To understand the technical nuances, it is necessary to distinguish between the two main variants of the die casting process:

1. Hot chamber die casting: In this process, the crucible with the molten metal is located directly in the machine (hence “hot chamber”). A piston presses the molten metal through a nozzle directly into the mold. This process is ideal for metals with a low melting point such as zinc, magnesium and tin alloys. The advantages lie in the extremely fast cycle times and high energy efficiency.
2. Cold chamber die casting: The hot chamber process is unsuitable for metals with a high melting point, such as aluminum and brass alloys. In the cold chamber process, the required amount of molten metal is taken from an external furnace and poured into the machine's cold casting chamber. A hydraulic piston then presses this melt into the mold at enormous pressure. Although the cycle times are somewhat longer, the cold chamber variant enables the processing of high-strength lightweight materials such as aluminum, which are of central importance for transport and environmental technology.

For our customers, aluminum die casting using the cold chamber process is by far the most relevant process for the production of structural components, housings or heat sinks.

The die casting process chain: from raw material to finished part

A high-quality die-cast part is the result of a perfectly orchestrated process chain. As technical problem solvers, we at Trade World One understand that every single step must be mastered in order to guarantee the specified quality.

1. toolmaking for die casting: the heart of the process

The Die casting mold is the most critical element that goes into the Die casting machine is installed. It is made of high-strength, heat-resistant tool steel and has to withstand extreme thermal and mechanical loads. The complexity is considerable:

• Mold cavity: It defines the external geometry of the component and must be manufactured with the highest precision (often in the µm range).
• Cores and sliders: Movable cores and slides are integrated into the mold to reproduce internal contours and undercuts. Their complex mechanics must function reliably over hundreds of thousands of cycles.
• Temperature control system: A sophisticated system of cooling and heating channels runs through the die casting mold to precisely control the temperature. This is crucial for minimizing distortion and optimizing cycle times.
• Sprue and venting system: The design of the sprue determines how the melt flows into the cavity. Incorrectly designed, this leads to typical Casting defects such as air pockets (Porosity) and incomplete filling.

The design and production of the die-casting mold requires enormous expertise. This is where we at Trade World One come in, using our global network to access specialized toolmakers whose quality we have verified.

2. melt and alloys: The basis for quality die casting

The quality of the end product starts with the raw material. Specific alloys are used (e.g. AlSi9Cu3 for aluminum). Exact adherence to the chemical composition is crucial for the mechanical properties of the die-cast part. The molten metal must be free of impurities and brought to an exact casting temperature.

3. the casting cycle in die casting: an act of precision

The actual casting process only takes a few seconds, but is physically highly complex:

• Mold filling phase: The piston accelerates the melt to speeds of up to 100 m/s and fills the mold cavity in milliseconds.
• Reprint phase: Immediately after filling, the pressure is massively increased. This phase is crucial to avoid cavities (shrinkage cavities) inside the part.
• Solidification and cooling: The mold's temperature control system draws heat from the melt until it solidifies.
• Eject: The mold opens, and ejector pins eject the finished part from the mold, often assisted by robots.

4. post-processing of die-cast parts: From blank to solution

A die-cast part is rarely finished after casting. A chain of post-processing steps follows:

• Deburring: Sprue and flash are removed.
• Mechanical processing: Although die casting is very dimensionally accurate (“near-net-shape”), functional surfaces such as sealing seats or threads often have to be brought to the final tolerances by CNC milling or turning.
• Surface finishing: Depending on the application, steps such as blasting, vibratory grinding, powder coating or cathodic dip painting (CDP) follow for maximum corrosion protection.

Our role is to oversee this entire process chain. We do not supply blanks - we supply ready-to-install die-cast solutions.

Materials in die casting: a comparison of aluminum, zinc and magnesium

Material selection is a strategic lever. Choosing the right material is crucial for the function and cost optimization of every project. Three material groups dominate:

• Aluminum die casting (Al alloys): The material of choice for most applications in transportation and environmental technology.
  • Advantages: Excellent strength to weight ratio Weight (ideal for the Lightweight construction), high thermal conductivity (perfect for Heat sink), good corrosion resistance and recyclability.
  • Application examples: Gearbox housings, housings for signaling technology, support structures, pump housings - all typical die-cast applications.
• Zinc die casting (Zn alloys): Zamak alloys, processed by hot chamber die casting.
  • Advantages: Enables extremely thin wall thicknesses and maximum imaging accuracy. The excellent surface quality allows direct electroplating.
  • Application examples: Precise sensor housings, complex levers and fittings, decorative panels.
• Magnesium die casting (Mg alloys): The champion of lightweight construction, 30 % lighter than aluminum.
  • Advantages: Lowest density, excellent attenuation properties and very good EMI/RFI shielding.
  • Application examples: Housings for mobile control units, steering wheel skeletons, covers - wherever die casting has to be extremely light.

We actively support you in selecting the optimum material for your specific application.

Procurement of die casting & components: Solutions for purchasing

The procurement of die-cast parts is a complex technical project. This is precisely where our strength as a technical partner lies.

Challenge 1: High tool costs and the right choice of supplier

The die-cast mold represents a major challenge Tool costs represents a significant initial investment.

• Our solution: We use simulation tools (Moldflow) to optimize the tool concept right from the start (“Right First Time”). Our global supplier network will find the right toolmaker for your project to optimize cost, quality and delivery time and protect your investment.

Challenge 2: Quality assurance in die casting

Porosity, distortion, cracks - there are many potential sources of defects in die casting.

• Our solution: Our ISO 9001-certified quality management, supplier audits, precise inspection plans and complete documentation are standard. We ensure that every part meets the specifications before it leaves our warehouse.

Challenge 3: Reproduction of obsolete die-cast parts

What happens if a component fails after 20 years and no drawings exist?

• Our solution: We specialize in manufacturing according to samples. We have already reproduced obsolete brake linkages from die castings for a transport company without drawing specifications. Our process includes 3D scanning, material analysis and reverse engineering to design a new tool and manufacture tested spare parts. This service ensures the operational readiness of your fleets.

Challenge 4: Global supply chains for die casting

Political instability or logistics crises pose risks.

• Our solution: Our in-depth knowledge of global procurement markets is embedded in our corporate DNA. We diversify supply chains, proactively manage logistics and use our warehouse as a buffer to ensure your security of supply for all components.

Future & trends: from giga-casting to sustainability in die casting

• Simulation and digital twin: Virtual optimization of the die casting process reduces errors and development time.
• Structural die casting: Particularly relevant for the E-mobilitywhere extremely large die-cast parts such as battery trays replace entire body assemblies. This process is also known as “giga-casting”.
• Sustainability: The use of secondary aluminum (recycling) is becoming the standard in order to massively reduce the CO2 footprint.
• New die casting alloys: Research is continuously developing new alloys with improved properties to meet increasing requirements.

Conclusion: Why die casting is a key technology for the industry and why we are the right partner

Die casting is a key technology for manufacturing complex, lightweight and highly resilient components that are at the heart of modern transportation and environmental technology. However, the path from the idea to the finished, quality-tested component is complex.

Success depends on having the right partner who understands your technical requirements, masters the global markets and delivers reliably.

At Trade World One, we live this partnership. With our team, our deep industry DNA and our uncompromising focus on solutions, we are more than just a supplier. We are your technical problem solver and implementation guarantor for every project. Whether new development, optimization or the reproduction of an obsolete die-cast part - we will find a solution.

Because we are driven by your challenges. Our promise is our motto:
Components. Solutions. Availability.

Sources

• Die casting - WikipediaComprehensive introduction to the die casting process, explanation of the technology and differences between hot and cold chamber die casting.
• Dissertation RWTH Aachen: Sheet metal reinforced hybrid structures in die castingScientific study on interface analysis and warpage optimization in die casting.
• TU Clausthal: Hollow aluminum structural components using salt cores in die castingIn-depth study on the use of innovative salt cores in the production of complex structural components in die casting.
• Dissertation University of Stuttgart: Microstructure and creep behavior of magnesium die casting alloysScientific work on the material properties of Mg-based die casting alloys.
• TUM dissertation: Holistic concept for the use of indirect metal laser sintering for die castingResearch on rapid tooling as an innovative approach for prototypes in the die casting process.
• Proguss Austria: Technical article on the hot cracking sensitivity of aluminum die casting alloys: Methodical investigation and comparison of different alloys and casting processes in the context of hot cracking.
• ScienceDirect: The Casting - Engineering OverviewScientific resources and overviews of the die casting process with a focus on industrial applications.
• MDPI Metals Journal - Special Issue on Die CastingCollection of current scientific articles and studies on various aspects of die casting.
• SpringerLink: Recent Advances in Die Casting Technology: Technical article on technological development and optimization in the die casting process.
• Taylor & Francis Online: Modeling and Simulation in Die CastingScientific paper on simulation techniques for the improvement of die casting processes.