Carat solutions

Gear shift for the car industry

Car manufacturers are at a watershed as they move further into the age of electric vehicles. With this change comes a shift in production methods, and Bühler is fully prepared for the new challenges.Car manufacturers are at a watershed as they move further into the age of electric vehicles. With this change comes a shift in production methods, and Bühler is fully prepared for the new challenges.

Change drives innovation

The electro-mobility revolution has brought with it a radical rethink around car production methods. Both established and new car producers are looking to simplify their production methods and save costs by reducing the size of their factories by producing ever-larger components that require fewer robots to assemble them. The industry is even changing the materials they use to manufacture cars.

Car manufacturing traditionally involved stamping sheets of steel into the shapes needed. A typical car would be made up of hundreds of different steel parts that needed to be welded and fitted. In 1993, the car manufacturer Audi took a radical step when it introduced the Audi Space Frame concept for one of its luxury sedans. It was the starting point for a new manufacturing process. Instead of steel, Audi used aluminum and integrated casted structural parts created by using a process called high-pressure die casting. It involves molten aluminum being shot into a die or mold in milliseconds and then being solidified under high-pressure compression.

Between 2000 and 2010, a handful of luxury car manufacturers started to follow Audi’s example and began using structural castings in their designs. While the parts were varied the volumes were low as early adopters still restricted their usage to luxury ranges. Over the following years, more manufacturers switched to die casting. One example is the production of the shock tower, an integral part of a car’s body in white, the stage where the car frame has been joined together and is yet to be painted.


We see enormous opportunities for die casting, as newcomers are changing the market by opting for the advantages of the aluminum die-cast method.

Michael Cinelli, Product Manager Die Casting

Rapidly changing market demands

But it was increasing environmental standards requiring greater weight reduction in vehicles along with the desire to cut production costs that started to drive a more radical change in the market. A process once limited to a few luxury car lines was now catching the attention of car producers across all price ranges. Out of the 78 million light vehicles produced globally in 2020, 6 million involved structural castings in their manufacture.

It is still a small proportion of the market that includes aluminum die-cast parts in car bodies, but that figure is expected to grow to around 25 million by 2030. Michael Cinelli, Bühler’s Product Manager for Die Casting, believes the auto industry is at a watershed. “We see enormous opportunities for die casting as newcomers are changing the market by opting for the advantages of the aluminum die-cast method. On one hand, there’s the trend toward further implementation of structural components in many different car segments,” he explains. “On the other hand, the new body-in-white-concept is a highly interesting development, resulting in growing demand for bigger die-casting solutions.”

This market development led Bühler to expand its portfolio last year with the inclusion of the Carat 560, the Carat 610 and the yet-to-be-launched Carat 840, capable of a locking force of 84,000 kN (just over 8,500 tons). The locking force is the force used to keep the two halves of the die together. The greater the force, the larger the component that can be produced in one shot of aluminum under a certain pressure. These machines are big; the smallest of the three, the Carat 560, weighs about 400 tons, or the same as a Boeing 747-400.


Extending the Carat die-casting machine series


Cinelli believes the move to larger machines has in the past been inhibited by what he describes as a “chicken and egg” situation. “Car designers did not think about large component sizes because the machines to make them were not available and we had no reason to build bigger machines because there were no components requiring such large machines,” he explains. Now that the market has changed, car manufacturers realize that to remain competitive they need to fundamentally rethink their production setup – with the die-casting process at the heart to increase flexibility and efficiency.

It is the rise of electro-mobility that has proven to be the greatest market disruptor. New car manufacturers realized that going straight to die-cast production was more cost-effective when it comes to start-up costs. This is particularly true for newcomers that don’t already have the stamping and assembly lines in place necessary for traditional sheet metal production.

Companies such as Tesla are also finding that larger machines, when producing a single large component, can result in doing away with costly welding and assembly processes. Fewer processes require a smaller factory footprint and overall lower investment to produce greater volumes. Tesla is currently using 6,000-ton die-casting machines to produce the rear underbody for its Model Y car in the US and in China, according to statements made by Tesla CEO Elon Musk in the 14th episode of the podcast “Third Row Tesla” released in April 2020.

This single piece casting combines 70 different stamping parts and reduces the number of robots required by 300 and the factory footprint by 30 percent. Larger machines are also capable of producing more components in one shot. Shock towers are typically cast one or two at a time, taking around 70 seconds each. A die-casting machine large enough to produce four shock towers in one shot can significantly increase productivity and cut costs.

A key component for a greener future

Carbon emission reduction is central to the ethos of electric vehicles, which is why manufacturers are also looking to lower their production emissions. Primary aluminum production is very energy intensive, so companies are looking for ways to produce it using renewable energy sources. Manufacturers are turning to countries such as Dubai, where solar power is used, and Norway with its abundant hydro-electric resources, to produce aluminum. All these fundamental changes offer unique opportunities. “The die-casting industry is at a cross-roads as more manufacturers adopt a new philosophy towards their production methods,” Cinelli explains. “We believe current market forces are pushing the car industry towards die casting as an alternative to sheet metal design, and Bühler is absolutely ready to meet this new demand with our expanded Carat range.”


About the Carat series:

The Carat two-platen solution with minimum deflection and a high degree of dimensional accuracy has long-proven its value for the production of large and complex structural components. The unique Bühler shot control system, for real-time closed-loop control, allows for consistent high quality part production.

All the machines in the expanded Carat portfolio are delivered with the DataView control unit – which makes the control of the die-casting machine easier and more intuitive via its multitouch screen. Additionally, every machine is equipped our new energy frame concept with a clear and distinctive arrangement of energy couplings. The Carat series also offers the option of servo drive technology.

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