AM arrives in the Automotive Industry

Text: Thomas Masuch; Photos: GKN / Thomas Masuch

As it fine-tunes its approach to additive automotive production at its innovation center in Germany, GKN Additive is hoping to tap into significant economic potential.

 

Not far from its glowing-hot sintering furnaces and metal presses rated at hundreds of tons, GKN has established a center for additive manufacturing in Radevormwald (near Cologne). There, a row of well lit, elegantly designed 3D metal-printing machines can be found behind a wall featuring an illuminated green corporate logo. The visual impression alone lets visitors know that this is a place where a new age of production is beginning.

Building up an additive manufacturing area at its German innovation center is a key part of GKN’s ambitious plans. »Our goal is to make series production a reality in the automotive industry,« declares Simon Höges, the group’s director of advanced AM technology.

GKN uses sintering technology to produce 11 million parts every day, which makes it one of the world's largest automotive and aviation suppliers. To realize its plans for the future, the group will need to take additive manufacturing to an all-new industrial level. Unlike other sectors – aviation, for example, where the advantage of AM mainly lies in weight reduction – the automotive industry focuses primarily on productivity. »We face a completely different kind of cost pressure,« Höges reveals.

 

 

We face a completely different kind of cost pressure.

AM is now one of the core topics

Back in 2013, GKN started a business development project in which it wanted to identify and expand on sensible forward-thinking ideas. »Along with e-mobility, additive manufacturing is now one of our core topics,« reports Höges, who earned his doctorate at Fraunhofer ILT (Aachen) and has been responsible for establishing the AM section of GKN's innovation center since 2014.

To advance these efforts throughout the group, GKN consolidated all of its AM-related activities under the division GKN Additive. This division now comprises 100 employees and has an external profile equal to that of GKN Aerospace, GKN Driveline, and GKN Powder Metallurgy.

 

 

Since powder metallurgy is one of the group's core areas of expertise, GKN is concentrating on metal in additive manufacturing, as well. Being a world-leading producer of such powder offers a number of additional benefits. Using the proven production methods PM (powder metallurgy) and MIM (metal injection molding), GKN typically manufactures quantities that start at around 100,000 units and have no real upper limit.

In additive manufacturing, it now wants to start offering lot sizes of less than 10,000. »That's where we've had to turn down a lot of projects that weren’t a good fit for our production facilities,« Höges explains. »As we incorporate AM into our operations, we're seeing plenty of demand in this area alone.« He adds that on the whole, AM is enabling GKN to »improve our coverage of entire product life cycles« (see graphic on top).

GKN BECOMES A BETA PROGRAM PARTNER

In developing additive series production, one of the obstacles GKN faced involved finding the right machines. »Quite a few systems were designed to produce prototypes, which didn't seem like a match for us,« Höges recalls. GKN was looking for more of a »machine tool«, which it eventually found through Additive Industries. This young Dutch machine manufacturer won Höges over with both its »vision and its mechanical concept for series production«, as he puts it. As a result, GKN was one of the first customers to get involved in the company's beta program as a development partner.

 

 

It then took delivery of an Additive Industries MetalFAB1 in Radevormwald in October 2016. At that point, Höges and his development team began working on achieving high (and reproducible) levels of component quality and density. An adjacent lab also examined the microstructures of numerous test series. This resulted in improvements to the MetalFAB1's hardware, which GKN discussed with Additive Industries in their regular monthly meetings.

By the time the beta testing phase ended in December 2017, GKN had already produced and shipped multiple components. »It did require a lot of technical expertise in terms of using the machine, though,« Höges concedes. Plans are thus in place to simplify the operation of the MetalFAB1 before it makes its way to its final destination at GKN's production facilities in Bonn in the first half of 2018.

»WE'RE BECOMING A MAJOR USER«

Along with the MetalFAB1, GKN has other laser melting machines (including from EOS and Renishaw) at its disposal in Radevormwald. These systems serve as both production units and a benchmark for the MetalFAB1's development. »Our lineup of machines is probably going to keep expanding, especially at our production plant in Bonn,« Höges predicts.

With its selective laser melting (SLM) systems, GKN will be looking to offer the lower quantities required in the production chain for small and complex high-end parts. At the same time, the group is also going to be manufacturing larger lot sizes of several thousand units using binder jetting technology.

This method is relatively similar to the MIM procedure that has been employed for decades, which means GKN will be able to leverage its wealth of experience in sintering. Since parts produced through binder jetting exhibit a lower relative density than SLM components, Höges sees numerous potential applications in the automotive sector – especially as a complement to MIM and powder metallurgy.

RESEARCH ACHIEVING FURTHER EFFICIENCY GAINS IN PRODUCTION

To ensure GKN’s continued success with AM techniques in the future, Höges and his colleagues are exploring a range of other developments. One of their objectives is to keep improving production efficiency, which requires component designs that reduce postprocessing to a minimum and the automatic removal of supporting structures.

The team is also researching other basic materials (such as copper) with an eye toward qualification, along with hybrid construction techniques. Here, additive and powder-metallurgy methods are combined in intelligent ways – by applying axial pressure to powder, for instance – to achieve greater productivity. Tests are currently being conducted on gear wheels, where 3D-printed internal components can lead to significant reductions in noise.

For Simon Höges, there are already clear signs that these and other additive advancements will play a significant part in the success of the GKN group going forward. »We're working closely with our customers and partners on these future topics, and their feedback has been really promising,« he says.