It is not only in the manufacture of electric vehicles that China leads the world; suppliers in the Middle Kingdom are also driving the future forward. In aluminum die casting, the Duoli Technology Group is taking a prominent role – together with Bühler's megacasting solutions.
Burkhard Böndel, January 2025
The hall is not yet finished, walls and steel pillars are still being erected. The area exudes the charm of a construction site; access roads are muddy, made passable with centimeter-thick steel plates. Bare container offices stand in front of the building. But don't be fooled – anyone who wants to know where the global hotspot for megacasting is currently emerging should head straight to Changzhou, not far from Shanghai. Here, the Chinese automotive supplier Duoli Technology Group is building a new factory, which, when fully expanded, will house eight megacasting cells for producing the largest possible structural components.
The company is an inspiring example of entrepreneurial spirit and strategic foresight. Founded in 1998, Duoli has quickly developed into a key supplier of stamped and welded parts for the domestic automotive industry. Today, 14 locations are spread across China, with an annual turnover of around CHF 500 million. Despite this rapid rise, Duoli has always kept an eye beyond its immediate horizon. "We analyzed the trends in our industry and realized that we could only continue our success story if we also invested in a new future technology," says Jianqiang Jiang, General Manager of Duoli Technology Group.
We had to react quickly, and Bühler, as a leading provider [in the field of megacasting], was the partner of choice.
Jianqiang Jiang,
General Manager of Duoli Technology Group
Only 10 years after the company's founding, internal discussions began. It quickly became clear: "This future technology is megacasting," says Jiang. Tesla, which introduced integrated die casting and redefined the construction of the body-in-white, was the wake-up call, according to Jiang. Once again, everything proceeded at supersonic speed. Projects were approved in 2020, the first Bühler Carat 610 and 920 machines were ordered in 2021/2022, and production began at the Yancheng plant in 2023. And now, the Changzhou plant is the next milestone. Due to its proven expertise in aluminum die casting, Duoli selected Bühler as a strategic partner and sole supplier for this realignment. "Although die casting was initially uncharted territory for us, there are already highly developed technologies and teams in this field. We had to react quickly, and Bühler, as a leading provider, was the partner of choice," says Jiang.
With the help of megacasting, innovative car manufacturers and suppliers are revolutionizing vehicle construction. Up to 100 individual parts, which previously had to be welded together by hundreds of robots, can now be cast in one shot in aluminum. This brings enormous efficiency gains in production and a significantly improved environmental footprint.
Fewer individual parts mean fewer assembly and joining processes. This means that a complete body part can be cast in just 100 seconds. It also means simplified supply chains, which reduces logistics costs. And the reduction in material usage improves the environmental footprint of the finished product.
These structural parts – such as the front and rear underbodies – reach previously unheard-of dimensions, with shot weights of up to 100 kilograms. Understandably, this new weight class requires new machines that also surpass all previous models in terms of clamping force, dimensions, and weight.
To equip the new factory in Changzhou, Duoli ordered four of these giants, the Carat 920 model, from Bühler at the beginning of 2024 – each as large as a single-family home. First introduced to the market in 2023, Bühler’s solution quickly established itself as the leading option – orders from Volvo, Honda, and four other original equipment manufacturers (OEMs), have since been placed with Bühler. The Carat’s performance stands out thanks to its unique two-platen technology, digitalization and the integration of peripheral devices.
In Changzhou, the first Carat 920 had already been set up and was operational in early January 2025, with parts ready for assembling two more units.
However, it's not only the machines that are enormous – the demands on the unit, processes, cell, and tooling design have also increased significantly. It starts with the setup. While smaller machines are assembled, tested, disassembled, and then reassembled on-site at Bühler’s clients, this is impractical for machines of this size. Everything must be perfectly coordinated and simulated in advance to ensure there are no surprises at the customer’s site. "With cell solutions and machines with a locking force of 6,000 tonnes, everything has to fit seamlessly right from the start. The smallest mistakes would have costly consequences and a major impact on the project timeline and the start-up process,” says Cornel Mendler, Managing Director of Bühler’s die-casting business.
With cell solutions and machines with a locking force of 6,000 tonnes, everything has to fit seamlessly right from the start.
Cornel Mendler,
Managing Director of Bühler’s die-casting business
Due to the immense forces involved, even the installation site and foundations require a new level of quality. In just 80 milliseconds, up to 230 kilograms of molten aluminum are pressed into the 200-tonne mold, with hydraulic pressures of 210 bar and forces of 92,000 kilonewtons. This force is enough to lift the Eiffel Tower – not once, but every 100 seconds. Ultimately, up to 1,000 parts are to be produced per day, with wall thickness precision to within a few tenths of a millimeter. Nothing must give way or deform; the machine must operate with absolute precision and repeatability in the casting unit. The foundations are therefore up to 30 meters deep, with the surface ground so flat that the height difference across the entire area is less than a millimeter.
"Even a minor installation error can lead to large deviations. There’s no room for adjustments with the Carat 920, so the foundation must be absolutely precise," says Robin Lu, who heads Bühler's die-casting business in China.
Above all, the processes must be as perfectly synchronized as a Swiss watch. At these production volumes, an aluminum furnace is needed directly next to the machine, along with robot-controlled handling of the heavy parts, a cooling basin, and immediate optical quality inspection before the part moves on for further processing. Over 20 peripheral devices need to be coordinated. This is managed through Bühler’s powerful DataView machine control, which integrates all process-related and quality-relevant peripheral devices.
It is supported by Bühler’s SmartCMS, a higher level of control that orchestrates the entire cell. When the first Carat 920 was powered up at the Changzhou plant in early January 2025, reliable experience from the smaller Carat 610 in Yancheng was available. For almost two years, Duoli has been producing body parts there in the megacasting process for automakers. The Bühler machine produces around 600 parts daily. "Bühler has met all agreed specifications," says Jiang.
Motivated by these successes, Duoli and Bühler are working together on further improving the parameters: “We want to increase production to 800 parts per day,” says Sun Jianxin, who is responsible for production at Duoli. Sun Jianxin joined Duoli from an OEM with his team. In his previous position, he managed several factories and knows what it takes to optimize production: “Our teams work together excellently,” he says.
We want to become the largest megacasting producer in China. After that, we’ll expand our business globally.
Jianqiang Jiang,
General Manager of Duoli Technology Group
In the medium term, Jiang expects further progress as more experience with megacasting accumulates: “We are still at the very beginning,” he says. “Most of the costs in megacasting are determined by the design of the parts. We had to develop a deep understanding of the entire process chain, from post-casting finishing to equipment maintenance.”
A thorough understanding of these points is essential to further increase efficiency and reduce costs. But anyone who has come to know Duoli has no doubt about the company’s ability to implement these operational principles. The company’s long-term strategic direction is no surprise either: “We want to become the largest megacasting producer in China,” says Jiang. “After that, we’ll expand our business globally.”
Who: Duoli Technology Group
Where: Headquartered in Shanghai with 14 locations across China.
When: The company was founded in 1998.
What: Duoli is a Tier 1 OEM supplier with stamping, welding, die-casting, and thermal forming business.
Customers: The company serves many well-known global OEMs in the domestic car manufacturing industry.
Bühler: Duoli has Carat 610 and Carat 920 die-casting solutions from Bühler.
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