Team spirit in lightweight design
Aluminum has a long history of use in the automotive industry. Now experts are trying to develop alloys that will let auto makers use highly automated joining techniques. Corrado Bassi from Novelis believes that remote laser welding is the method that shows the most promise.
ars and cans are the biggest drivers of growth in the aluminum market. Weight and stability play a key role in both applications. But in the packaging industry, the main focus isn’t really on the material, but rather on the coating solutions we develop in collaboration with our partners and customers. That’s not the case in the automotive industry.
There the material itself is constantly pushing our developers to work harder on areas such as plasticity, strength and joining techniques.
In search of automation
Obviously we’re delighted with every car built solely from aluminum, and of course we want to increase the
share of aluminum used in car making. But the future lies in composite construction — deploying diff erent materials in the right places to make the best use of each of their strengths.
Thanks to hot forming, steel has taken on a key role in lightweight construction and is generally the manufacturers’ preferred choice when it comes to structural components. But plastics and fi ber-reinforced composites such as CFRP are now coming into their own as loadbearing materials. And aluminum has clearly demonstrated that it’s a good choice for exterior components such as the hood, trunk lid and doors.
Our job as material manufacturers is to improve how our products work together. When you use lots of diff erent materials, things obviously get far more complex in regard to joining processes, corrosion problems and painting. One thing that’s very important is to fi nd solutions making it possible to use highly automated joining processes.
Unlike steel, these lightweight materials cannot even be welded to themselves, and they inevitably require some kind of fi ller metal.
fascinating remote welding
When it comes to welding tools for aluminum, I’m particularly interested in lasers, specifi cally remote laser
welding. The great distance between the optics and the workpiece makes the technology very fl exible, letting users
weld many diff erent seams, even in hard-to-reach places. That’s a big advantage particularly in automotive engineering, because component rigidity is a key criteria that depends in part on the joining process.
The Eiffel Tower comprises 7,300 tons of wrought iron. If it were to be built today using aluminum, it would weigh only 5,110 tons.
But especially in remote welding you have to work without filler wire and
shielding gas. So that’s why we’ve developed a special kind of sheet aluminum that makes this possible. We call this innovation “fusion”, and it involves casting two diff erent alloys in a slab. Aft er rolling, we end up with a core made of the standard 6000 series alloy used in car manufacturing and, on the outside, a layer of aluminum-silicon alloy that can be laser welded without filler.
We believe that laser welding and aluminum are a combination that off ers plenty of potential. That’s why I’m confident that developments of this type will become increasingly important.
Corrado Bassi is the auto development manager for Novelis at the company’s Sierre location in Switzerland. Novelis is a global market leader in rolled
aluminum products. Headquartered in Atlanta, Georgia, USA, Novelis operates 25 manufacturing plants and recycling centers in 11 countries and employs almost 11,000. E-mail: Corrado.Bassi@novelis.com
Lightness for everyone!
High rigidity combined with very low weight. Th ese are the prominent features
of carbon-fi ber-reinforced plastic — CFRP. Unfortunately, it is also expensive, leading to higher component costs than when using other lightweight materials. Andreas Wüllner from the SGL Group argues that innovative production methods will change all this—with the effect that we’ll soon be seeing a lot more CFRP and the like in everyday products.
Fiber-reinforced plastics are usually fi nished using conventional techniques such as milling and water jet cutting. Another method that holds great promise for the future is the laser, especially when it comes to high volumes, repairs and preparation for adhesive bonding. As a manufacturer of fiber-reinforced plastics, however, we don’t favor any one particular method.
ready for mass production
What matters most to us is strengthening this material’s position in the market. We do this by working with our
customers to develop and promote new and innovative applications and optimized production methods. In the past,
CFRP and similar composites were used primarily in industries such as the aircraft and wind power sectors, as well as in sports cars and Formula One racing. Those are generally areas where you’re looking at comparatively short production runs and longer manufacturing cycles. As a rule, the components are made by baking layers of CFRP in an autoclave, and this is a time-consuming process.
What’s new is that we’re now seeing composite materials entering mass production to an ever greater extent. One example is the auto industry. One prominent example is the inclusion of CFRP as a standard material in the body of the new BMW 7 series. These kinds of applications obviously involve high volumes, and that’s making the production methods better and more innovative in terms of lead times and the whole approach to component manufacturing. And of course that ultimately reduces the cost per part.
fast flow of resin
As a material manufacturer, we support this process in a number of ways, for example by optimizing the weave of
the mats and the orientation and weight of the carbon fibers. That makes the resin flow faster through the fibers, achieving optimum distribution within the part. And we also support our customers and advise them how to keep
scrap rates as low as possible, for example by using tools that are very close to the final shape.
An Eiffel Tower made of CFRP would weigh just 1,460 tons instead of 7,300. Of course, at today’s prices, it would cost 50 times more than the iron version.
By constantly enhancing the material, we also open up access to new applications. One example of a new product line introduced by the SGL Group are the fiber-reinforced thermoplastics that achieve especially short cycle times and can be welded, repaired and recycled. We also actively seek out collaborative projects and put signifi cant resources into basic research and issues that aff ect the industry. For example, we work in partnership with the chair of Carbon Composites at the Technical University of Munich and we are co-founders of an industry association — Carbon Composites e.V. (CCeV).
Our goal is to get to the stage where fiber-reinforced plastics are no longer a luxury application but rather an integral part of many everyday products.
Andreas Wüllner heads up the SGL Group’s composite materials business. SGL is one of the world’s leading manufacturers of carbon-fiber-based products and materials, operating 42 production facilities worldwide. The company is headquartered in Wiesbaden and employs some
6,300 people. E-Mail: email@example.com
Production experts say that producing producing components made from plastics and metals is no easy task. Dr. Harald Ott from Albis Plastic GmbH agrees, and adds, “But that’s where the best opportunities are found.”
Plastics are nothing new in the world of lightweight construction. Virtually all the components used in car interiors, for example, are made at least partly from plastic, from the dashboard and switches to the interior trim.
Even in areas where metals have traditionally reigned supreme — such as the engine compartment and chassis — we are beginning to see the use of highly reinforced polyamides and high-performance plastics as mounting systems for engines and transmissions. And engineers are increasingly using specially fabricated compounds for car body components such as bumpers, fenders and glazing.
Focus the bigger picture
This trend is likely to continue, largely because it off ers considerable potential to reduce a vehicle’s overall weight. Another exciting development is the move toward making components more multifunctional, adapting the materials they contain or their design or manufacturing processes to let them perform a wider range of functions. This approach can help cut costs and reduce manufacturing complexity. Yet for all these developments, I think that much of the potential inherent to metals and plastics themselves has now been exhausted.
Now, the task for engineers and technicians is to focus more on the bigger picture, using new combinations of materials and processes to develop innovative products. To do that, they need to involve the suppliers of the relevant material groups early on. We support our customers by helping them design finished parts and tools in a way that makes the best use of a material’s properties, as well as by off ering custom development of the required plastic components.
laser applications for plastic
An Eiffel Tower made of polyamide would be completely weather- proof and resistant to UV light. Paris would no longer have to apply some 60 tons of special paint to the
tower every seven years.
When it comes to innovative manufacturing methods, the laser plays a crucial role. Some of the key processes used for plastics — along with using lasers in additive manufacturing (3D printing) — are laser structuring, marking and welding. Another method used for bonding plastic parts is laser transmission welding, a process in which the laser passes through an upper transparent piece of material and only heats the laser-absorbing piece of material below, creating a highly defined joining zone. We offer a wide range of solutions to meet all kinds of needs and we can also modify those solutions for custom applications.
In plastic-metal hybrid manufacturing, for example, we first use suitable lasers to structure the surface of the metal. Then we inject a plastic component and create a secure bond between the two. Keeping up with our customers’ changing demands is essential, so we work closely with partners in business and industry and participate in research projects.
That’s the only way to provide our customers with the professional support they need to develop new and innovative products.
Dr. Harald Ott works as senior manager for product development at Albis Plastic GmbH in Hamburg. The company represents leading European brands
and manufacturers as a distributor of thermoplastic products. It also works in the field of compounding, creating its own highly specialized compounds for a broad range of applications. E-mail: firstname.lastname@example.org