Cheng Xu: ‘continuous development is necessary’
5/2/2024 Lightweight trend Die casting process Interview

Cheng Xu: ‘continuous development is necessary’

The die casting industry seems to agree that megacasting has potential. The fact that the Chinese market in particular is developing rapidly is not lost on European car manufacturers. In an interview, Cheng Xu, Chief Engineer of Casting at Chongqing Millison, talks about the intense competition in China, the process-related challenges and the expansion of the industrial use of the technology.

Cheng Xu standing in front of die casting parts.

Your company uses megacasting to manufacture vehicles. How long have you been using this technology, for which components and for which models? 

Cheng Xu
: Millison initiated pre-research on equipment and mold parameters in 2019. In April 2022, a formal trial mold of 8,800 tons was conducted, resulting in a successful first sample delivery. In November 2022, mass production officially commenced, with the mass production of 7,000 tons officially commenced underway in February 2023.

We employ this technology for the production of structural components in E-vehicles, such as the front cabin, rear floor, and battery trays etc. Notable applications include the NIO’s E-vehicle models of ES8 and ET5, as well as structural components for some renowned traditional European automotive companies. 

The technology is considered to be demanding in its application. What is your experience with it so far? 

Cheng Xu: Indeed, the application of new non-heat treatment material, the design of equipment parameters, mold design and process design for die casting manufacturing is no longer a simple of selection. Instead, it builds around a creative process based on „first principles”. In the absence of experience and standards, many die casting manufacturers and OEM automotive companies have engaged in Megacasting, exposing them to meaningful risks.Although the interim results may vary, each with respective advantages, the different manufactures all encounter significant challenges.

From a business perspective, the first requirement is a sufficient number of orders to support the investment in multiple sets of molds, ensuring optimal equipment utilization, while the qualification rate is also crucial. Meanwhile, to maintain the thermal balance of the molds, high energy consumption is another significant issue that needs to be addressed.

Part of a megacasting production line
From the perspective of the solidification process, as the size of the machine models continues to grow, there is a longer heat exchange time for the aluminum alloy before entering the cavity compared to that of the smaller die-cast structural components. Hence, Escs (externally solidified crystals) poses a significant challenge.

Personally, I believe this will be one of the most crucial bottlenecks limiting the development of larger die-cast components. I have carefully studied the research of Prof. Dr.-Ing. Wolfram Volk from the Technical University of Munich about megacasting, and I strongly agree with his views.

When the tonnage reaches a certain level, both equipment and processes will reach their limits, and we cannot freely introduce different mechanical properties into specified locations. The degradation of mechanical properties is ultimately inevitable with the deterioration of filling conditions. As a result, we are also actively researching solutions to address the aforementioned challenges.

As mentioned, after three years of engineering design and one year of the mass production process, we have prevented the occurrence of many problems and optimized various process issues. However, some challenges are not isolated, as they stem from systemic process flaws in die casting. We are still working diligently to address these fundamental process deficiencies in the die-casting system.

What are the most important goals you want to achieve with megacasting? Will they be achieved?

Cheng Xu: We aim to support the automotive industry to achiev faster and more cost-effective productions through this technology, creating values for customers and offering more possibilities for environmentally friendly transportation. Importantly, we do not rule out other industrial applications. Based on the information at my disposal, I believe that this goal has been partially attended, but continuous development is still necessary. I am confident that this technology will ultimately realize its intrinsic value.

TREND REPORT Megacasting

An increasing number of car manufacturers want to use ever larger structural parts made of die-cast aluminium in vehicle production. The trend towards megacasting appears to be unstoppable. However, opinions differ on the possibilities, limits and effects of the technology. This is the essence of the current TREND REPORT, for which the EUROGUSS 365 editorial team interviewed numerous industry experts. Download the TREND REPORT Megacasting now!

Are you planning to expand the use of megacasting?

Cheng Xu: We have been cautiously and steadily expanding investments for the production capacity of 8,800 tons and 7,000 tons. Additionally, we are actively engaged in pre-research and planning for machines with clampingforce of 16,000 tons and 20,000 tons.At that point, innovative technical solutions will be introduced to overcome equipment limitations and address process deficiencies.

During my studies in Germany, my professor, Thomas Steinhaeuser once mentioned to me that the size of equipment is determined by the market. I believe this is a bit of a chicken-and-egg situation. As casting engineers, our first task is to provide the market with more possibilities.

Many European car manufacturers seem reluctant to use megacasting. Chinese manufacturers, on the other hand, are perceived as pioneers. What are the reasons why megacasting solutions are in high demand in China? 

Cheng Xu: I find this issue to be multidimensional. 

Firstly, Europe possesses the world's most powerful traditional automotive technology and manufacturing capabilities. The inherent production systems and resources are highly mature, requiring a careful balance in aspects of large-scale transformation of the existing production mode. Indeed, Japan faces similar circumstances, but Japan has also begun its own transformative initiatives.

Furthermore, we are aware that Tesla was the pioneer in launching this application, but we have yet to see similar automotive companies in Europe. 

Lastly, let's talk about China. On one hand, China provides a favorable entrepreneurial environment in the new energy vehicle industry, with many entrepreneurs who do not bear the burden of traditional automotive companies' existing production systems and materials. Moreover, compelled by the intense market competitions, there is a need for rapid product iterations, which is a trend that European automotive companies, I believe, have also observed.

On the other hand, China has an abundance of engineers and a comprehensive supply chain from A to Z. From my personal perspective, these factors have contributed to China's rapid development in megacasting.

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Editors EUROGUSS 365