Gear shift for the car industry

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.

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.

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.”