Mahle Advances 3D Printing Capabilities

Its new 3D printing center in Stuttgart aims to accelerate prototype production with an eye toward establishing processes for industrial series production.

Mahle’s new 3D printing center houses the printers, powder preparation module, testing laboratory and a blasting system for finish-machining the components. (Mahle)

Slashing the time to produce prototypes for complex components, from several months to a few days, explains in part why Mahle’s technology group decided to build a new facility for additive manufacturing (AM) processes at its Stuttgart headquarters. The 3D printing center houses the printers, powder preparation module, testing laboratory and a blasting system for finish machining the components to satisfy internal prototype production as well as automotive and commercial-vehicle customer orders.

In the laser powder bed fusion process, a laser beam solidifies metal powder layer by layer to form components. (Mahle)

“The development of new systems and components has to be much faster today than it was a few years ago, especially when it comes to e-mobility,” Andreas Geyer, head of Process Technologies in Central Research at Mahle, said during a recent press event introducing Mahle’s new AM capabilities. “We are boosting the performance of our existing portfolio through possibilities in production design.”

Highly complex parts can be produced quickly using 3D printing. (Mahle)

The other main reason for opening such a facility is to enable 3D printing for series production that meets the strict standards of the mobility industry. The focus is on developing and qualifying manufacturing processes for components in thermal management, mechatronics and electronics – for example, to produce transmission and electric motor housings, charge air coolers, oil filter housings and heat exchangers, as well as structural elements, mounting devices and connections.

“We want to be prepared today to find out how we can use an integrated 3D printing [development process] according to automotive standards for later large-scale production,” Geyer said. “This opens up completely new possibilities in product development and manufacturing, because these processes can be used to produce high-performance components that cannot be manufactured using conventional methods.”

Successfully producing pistons and charge air coolers for the Porsche 911 GT2 RS reinforced to Mahle the need to open its own 3D printing center. (Porsche)
Manual finish-machining is carried out at the end of the process by specially trained staff. (Mahle)
Andreas Geyer, head of process technologies in Mahle’s central research. (Mahle)

The center processes two standard metal materials: aluminum-silicon-magnesium (AlSi10Mg) and stainless-steel 1.4404 alloys. Mahle 174+ aluminum alloy, suitable for pistons in truck diesel engines with high loads, also was adapted to AM. In addition, a couple of plastics materials can be used on Mahle’s network of 3D printers, Geyer said. “Copper is a material that might be used in the future, but currently aluminum is the important material for heat exchangers,” he added.

Laser powder bed fusion is used to form the component layer by layer. Mahle currently can manufacture components up to around 30 x 30 x 40 cm (11.8 x 11.8 x 15.7 in). After the printing process is complete, the finished parts are separated from the base plate and finish-machined by hand by specially trained staff.

In a joint project with Porsche and Trumpf last year, Mahle engineers successfully produced and tested high-performance parts such as pistons and charge air coolers for the Porsche 911 GT2 RS. “This was one of the milestones that also led to our decision to establish our own 3D printing center with our own printers,” Geyer said.

The project proved expected advantages of the 3D printing process – namely the elimination of expensive production tools and the ability to create structures otherwise too complex to produce. “Computer-aided topology optimization, which is modeled on natural structures, adds material only at stress points,” Geyer said. “This is how it adapts the structure precisely to the load.”

Commercial vehicles also can benefit from the new center. “Certainly with respect to the heat exchanger, we’re currently intensively working on various projects in the field of thermal management. And of course, commercial vehicles in conjunction with alternative drives are a focal area,” Geyer said.