New alliance for electromobility

When a network electrifies What fits together technologically and strategically is growing together: the medium-sized machine manufacturers Gehring and Wafios are pooling their expertise together to offer the global automotive industry complete turnkey production lines for hairpin stators.

The first step towards the new, medium-sized network was already taken in November 2020, when the family-run Nagel Group from Nürtingen took over the plant and machine manufacturer Gehring in neighbouring Ostfildern (near Stuttgart), which further strengthened its role as a technology partner for production systems for electromobility. The next important step is the intensive cooperation with the forming specialist Wafios from neighbouring Reutlingen.

Electromobile network
As a result, a network of two strong medium-sized companies with a total of almost 3,000 employees is being created in the Stuttgart area, one of the most important locations for the automotive industry in Germany. Together, Gehring and Wafios will be implementing stator assembly lines for all important automotive locations worldwide, from the initial idea to commissioning.

"Wafios and Gehring are forming an alliance that will enable us to build a powerful presence on the market for manufacturing systems for stator production," explains Dr Wolfram Lohse, CTO at Gehring. "This cooperation will allow us to make the entire process chain more efficient because we take a comprehensive view of the technologies and don't just focus on individual processes." The cooperation, therefore, offers everything from a single source - from prototype production to systems for series production. Another important aspect: The OEM has only one contact for the entire process chain. 0

"The biggest beneficiary are the car manufacturers. They benefit from our extensive know-how, developed over many years, which eliminates all unnecessary interfaces and friction points from individual solutions," explains Tobias Single, Head of E-Mobility at Wafios. "Together, we develop safe processes quickly and in line with customer requirements. In the process, each of us contributes the know-how around our core technologies." The cooperation combines Gehring's decades of experience in designing systems for automotive series production and Wafios' technological leadership in the field of straightening technology and wire forming, which is particularly important for the production of hairpins.

High speed in e-motor production: challenge for wire bending
The fast pace of high-volume production, in which electric motors are produced in under one minute, is a major challenge for stator production and its very complex wire-bending processes. Single: "We have mastered this complexity and can offer efficient, process-capable and future-proof overall solutions on the solid basis of our existing know-how. In addition, the bending process contributes significantly to quality: Anything that I do at the beginning, whether right or wrong, makes the processes further down the line easier or more difficult." This is where Wafios comes on board as the right partner for Gehring, because the FMU E bending machine has already proven itself many times over in the automotive industry in the small series production of hairpins. 

But it's not just about transferring existing technology to mass production. The collaboration is also tackling new developments to improve the performance and efficiency of electric motors. This is where a third partner comes into play.

PUR casting resin reduces heat loss and boosts electric motor performance
We are talking about the start-up company copaltec, which is developing special polyurethane (PUR)-based casting resins as a partner of the Nagel Group. The resins are introduced into motors using a vacuum process to protect them from external influences as well as overheating. "It can increase the performance of electric motors by up to 20 percent," says Jochen Nahl, consulting engineer at copaltec. "Our PUR-based resin has high thermal conductivity. The potting compounds used so far are used for insulation, for bonding cells and magnets, and as "gap fillers." That's why the battery and electric motor heat up: they need to be actively cooled." The start-up relies on the principle of "introducing thermal conductivity via potting compound," which significantly reduces the necessary cooling power, keeps the electric motor at a lower temperature level and, on the other hand, increases performance. Together with Gehring, copaltec is now developing machine solutions for industrialization in the electric drive train.

Scalable and modular: if required, the plant "grows" with the customer
The new medium-sized network can now offer all important core technologies - from bending to impregnation or final casting with copaltec resin. "Together, we develop scalable and modular solutions that are geared to the production philosophy of our customers," says Bernd Nagel, managing director of Nagel and the newly acquired Gehring Group.

"As a system supplier, we integrate the respective required conveyor technology and automation from suppliers. For example, full interlinking does not usually make sense with a maximum annual batch size of 50,000." Thanks to scalability, however, a system originally designed for small batches can also "grow" to accommodate large batches if required.

Smooth transition from stator prototype production to series production
"Thanks to the cooperation, the partners are coordinating all procedures across processes, thus improving the entire manufacturing process holistically across the entire technology chain," emphasises Dr Uwe-Peter Weigmann, CEO of Wafios. The technical risk involved in transferring know-how from small to large series is reduced thanks to the close bridging from sample production at Wafios and Gehring to complete series systems. But the cooperation does not end with delivery: The combination of the two service networks, which have been tried and tested in practice for many years, ensures rapid support in all the important countries.

While the electromobile theory is rather grey, the new prototype construction at Gehring's main plant in Ostfildern offers a colourful practical experience: complete plants for the production of hairpin stators and electric motors are located there. Together with the customers, the network partners use this as a basis for developing customised systems for the respective individual technologies such as wire bending or hairpin setting.

Gehring
The company is a recognised supplier of complete systems which, as an experienced partner to the automotive industry, has built up extensive knowledge in the various core technologies of stator production. The spectrum ranges from customised machine solutions for stator prototyping to systems for small-batch production and fully automated system solutions for stator production lines. Digital networking is handled by the Gehring Core IoT platform, whose cloud data helps to simplify the search for errors and identify productivity potential.

Gehring's extensive expertise in the customised development and manufacture of production machines speaks for itself. For example, the SNT machine series is characterised by the fact that it covers highly productive setting processes for different hairpin windings, which connect seamlessly to the Wafios Speedformers. The redundantly designed strands with pin production, pin setting and insertion of the generated wire basket increase technical availability and ensure scalable setup. An intelligent buffer system between Wafios Speedformer and Gehring SNT machines enables a robust transition between these operations.

Gehring know-how also plays an important role in the joining processes for hairpin stator production: the company maximises the utilization of energy- and cost-intensive laser sources by outsourcing unproductive non- productive time to separate stations upstream of the welding chamber. This reduces the number of welding machines and the investment outlay; it also results in a smaller footprint. In impregnation and insulation technology, too, Gehring achieves highly economical plants that are at the same time suitable for "batch size 1" production by cleverly combining heating processes.

The close coordination between Gehring and Wafios will enable all processes in this chain to be jointly driven forward in the future with regard to global optima in the interests of the customer.

WAFIOS
The company has many years of expertise in forming copper wire into plug-in coils known as hairpins, a flat wire-based alternative to classic round wire windings. The hairpin bending technology was developed with a view to smooth downstream processes for prototypes, small and large series. With this new technology, the hairpin legs can be positioned with high precision as one of the most essential quality features. The know-how plays a very important role in the bending of coated conductors, where the interaction of wires and insulating layer is crucial. The bending technology has already proven itself many times over in the automotive industry in the small-series production of hairpins. The experience gained here can now be transferred one-to-one to series production with its extremely short cycle times of close to one second.

To ensure that the quality is right in high-speed mass production, an intelligent camera checks typical geometrical features such as leg position during bending and ensures automatic compensation in the event of deviations. This optical in-process monitoring also enables the Wafios Speedformer to react at any time to changing boundary conditions such as fluctuating wire quality.

The tools play a very important role in bending. Wafios relies on tools that are largely independent of the geometry, because they allow complete pin sets for several stator variants, including special and phase arrestor pins, to be produced on a single line without changing tools. There are two plus points in favour of this solution: Customers get production with maximum availability, and they can respond flexibly to changing call-off numbers and geometries.

 

Profiles

Gehring
With over 90 years of experience, Gehring develops, among other things, technologies for highly efficient conventional and electrified powertrains. With its laser roughening, coating and honing processes, the company offers innovative solutions for combustion engines in response to current requirements of the automotive industry. Production technology for electric motors complements the portfolio and sets the tone for the future direction of the company. As a worldwide company, the Gehring Group is globally represented in key markets of the automotive and supplier industry, hydraulics and pneumatics, as well as aerospace technology.
www.gehring-group.com

WAFIOS
With around 1,100 employees, WAFIOS AG, Reutlingen, is one of the world's leading companies in the field of special mechanical engineering. It develops, designs and manufactures technically sophisticated machines for the wire and tube processing industry and for cold forming.
www.WAFIOS.com

copaltec
Since its founding in 2012, copaltec GmbH, based in Böblingen, Germany, has made a name for itself as an innovation leader in thermally conductive polyurethane-based potting compounds (PUR) that protect batteries, electric motors and electrical components from external influences and overheating.
www.copaltec.com

NAGEL
NAGEL Holding GmbH & Co. KG. in Nürtingen has 1,850 employees and is represented in 26 locations. In November 2020, the Gehring Group from Ostfildern, a global market leader for precision machining and specialist for stator assembly lines, has become part of the Nagel Group.
www.nagel.com