The colossus of die casting

A revolution is underway in the automotive industry. Instead of assembling a slew of separate stamped steel parts, vehicle manufacturers are die casting a few single aluminum modules to constitute a big portion of the body-in-white. Bühler’s colossal megacasting platforms, Carat 840 and Carat 920, help cut production costs and product weight, as well as improving the sustainability of automobile production.

 Bühler’s largest die-casting platforms each weigh upwards of 600 tons and occupy the space of a generous single-family house. And while the Carat 840 and Carat 920 are about as immobile as a house, in fact they provide a crucial contribution to modern mobility, as they enable auto manufacturers, especially those making battery-electric vehicles, to die cast ever larger parts in one piece.

A single aluminum megacasting replaces dozens of parts, potentially cutting production time and investment costs, while reducing the vehicle’s weight and improving its driving range.

“We are seeing a huge increase in the demand for ever larger solutions,” explains Michael Cinelli, Product Manager Die Casting at Bühler. “With our Carat 840 and Carat 920 we can offer our customers solutions for large structural parts with complex geometries and new body-in-white parts.” Megacasting pioneers are now looking to make the rear underbody of what is also called the body-in-white in one piece of aluminum. This will save them welding or gluing together 70 to 100 components – almost all of which have to be manufactured separately. 

Larger castings improve efficiency

By enabling automotive manufacturers to revolutionize how cars are made, Bühler is helping them to attain new levels of efficiency. Where they currently need an assembly line of about 300 robots to put together a rear underbody, automobile makers can switch to using a Carat 920 to produce it in one piece. As even Bühler’s largest machine only requires around 800 square meters of floor space, manufacturers could save around 30 percent of expensive production space.

Bühler’s largest die-casting platforms are truly shifting vehicle production into new territory. Manufacturers now have the ability to megacast structural parts as large as 1.8 meters by 1.8 meters. “We’re talking about the rear and front underbody,” explains Martin Lagler, Director of Global Product Management and Marketing for Die Casting at Bühler. “With our solutions, die casting these large parts is now part of the manufacturing process for automobiles.”

Bühler has made this significant step by working with customers. “It is a close collaboration. And the journey is just beginning,” says Lagler. Forming large amounts of aluminum in milliseconds is an extremely complex process. Manufacturers can today process twice as much aluminum in one die as they could only a few years ago.

 

Automotive manufacturers are rethinking production. We have the machines to put their future visions into reality and support them in developing all the processes to do so.

Martin Lagler, Director of Global Product Management and Marketing Die Casting at Bühler

“The Carat 920 is able to inject over 200 kilograms of liquid aluminum into a die within milliseconds, holding the die tight by applying a force of 92,000 kilonewtons to it,” explains Cinelli. “That’s 9,000 tons − the same weight as the Eiffel Tower. Imagine locking the die with the weight of that Parisian monument ensuring the excellence of every single shot.”

To cast ever larger and more complex parts, die-casting machines must be powerful and precise. Die casting aluminum structural components for vehicles took off a little over 15 years ago, and Bühler has been involved from the beginning. Vehicle makers were able to produce more and more models using aluminum in the body-in-whites, including structural components such as shock towers, longitudinal members, tailgates, and battery housings for electric vehicles. Large, yet lightweight, die-cast aluminum parts were a focus of industry innovation.

Bühler’s Carat series of machines has been a major driver in the segment for more than a decade. With its unique shot control and a casting process that protects the die, a Carat machine can help to increase overall productivity by up to 30 percent. Its two-platen closing unit ensures more stable production than less sturdy toggle systems, while better locking force distribution and reduced flash mean better repeatability and higher uptime. By automating it with Bühler’s SmartCMS system, all peripheral devices are fully integrated, thereby increasing the performance of the entire casting cell.

More than 800 Carat machines are in use today, making half of all structural parts manufactured worldwide. As they helped die casting to become standard in vehicle manufacturing, the trend towards megacasting gained more and more traction. “Automotive manufacturers are currently rethinking production in many ways,” says Lagler. “At Bühler we not only have the machines for them to put their future visions of even larger parts into reality, but we also support our customers in developing all the processes to do so.”

Reimagining die casting

Megacasting ever larger vehicle body parts is pushing the boundaries of die casting, and of every crucial complementary discipline – component design, alloy selection, melting, dosing, tempering, spraying, casting, extraction, cooling, deburring, marking, and final handling. In addition to supplying the right die-casting machines, Bühler also helps customers conceive the die-casting cell, from the melting furnace through the process chain to the finished part and its integration into existing manufacturing sites.

As aluminum die castings grow, all production steps must be reconceived to cope with the size and weight of the new megacastings – the fact that they can no longer be carried by humans is just one of the many challenges. That’s why Bühler works with its customers to conceive and commission entire process solutions from ingot to the body shop. Robots and transport racks, for example, are vital parts of an integrated transportation system that takes over the handling of megacastings from the jaws of the Carat machine to the body shop. “We at Bühler, and our partner network, can provide solutions for all these processes thanks to our wide practical knowledge in commissioning and running such large cells, collaborating with foundries and suppliers all over the world,” says Lagler.

Bühler helps manufacturers design and build complete custom solutions, with professional project management to deliver on time and on budget. Aside from planning and commissioning, Bühler also offers training, maintenance, servicing, and support once the megacasting cell is running.

 

With our Carat 840 and Carat 920 we can offer our customers solutions for large structural parts with complex geometries and new body-in-white parts.

Michael Cinelli, Product Manager Die Casting at Bühler

A future of zero scrap

Another upside of such solutions is the improvements in sustainability that they bring. Aluminum die castings can be almost CO neutral if low- CO aluminum alloys are used for production and green electricity to power induction melting furnaces. Cells are also constructed to catch aluminum overflow and re-use it directly, avoiding transport emissions and recycling costs. “Aluminum die casting can be close to CO neutral if foundries use recycled secondary aluminum and run their production on green electricity,” Cinelli says.

Bühler’s vision for the future of the die-casting industry is zero percent scrap, 40 percent less time to make a casting, and 24/7 production. “Advancing toward this vision is even more important. The larger the castings, the bigger the lever to minimize production costs by reducing scrap, cycle time, and increasing uptime of the die-casting system,” says Lagler. The aim is to make every shot perfect and to produce parts that are ready to install every time.

Benefits

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Megacasting reduces product weight and production time by replacing dozens of parts that have to be put together individually.

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A stand-alone megacasting cell cuts investment needs and production area by replacing robots and other devices.

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Making a megacast can be close to CO neutral if low-CO aluminum and green electricity are used.

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