Going Heavy in Lightweight

Germany’s expertise in lightweight engineering, design and services is generating exciting new opportunities and innovations in manufacturing, construction and other industries.

February, 2020

The Lilium jet is ready and requesting takeoff. A man standing in a field in southern Bavaria gets the “OK” on his radio and fires up the electric engines. The sleek aircraft’s wings are fitted out with 36 small ducted fans and 12 flaps that allow for vertical takeoff and landing – just like a helicopter but without the dangerous blades. The flying taxi achieves a velocity of 100kmh before landing safely.

The successful test flight in October 2019 was a momentous achievement for Lilium. Founded in 2015 near Munich, the start-up aims to offer aeromobility for all by creating a network of air taxi hubs. Its five-seater air taxis, designed to fly autonomously, are made possible thanks to lightweight technologies.

Engineers work on the Lilium jet. The flying taxi’s lightweight carbon fiber hull is essential for achieving electric-powered vertical takeoffs and landings. Where there are moving parts or mass needs to be transported, the rule is: the lighter the better.

© Lilium

Germany has become a heavyweight when it comes to lightweight technologies. Leichtbau, as it’s known in German, is an innovative branch that includes engineering, materials technology, design and services. The principles of lightweight technologies can provide substantial benefits across a range of industries, from aerospace to construction to robotics. Anywhere efficiency can be improved by reducing overall mass, you will find lightweight tech making an impact.

»I think we’re  approaching a renaissance in the lightweight industries «

Dr. Rainer Müller
Senior Manager of Lightweight Technologies at GTAI

Lightweighting can trigger a butterfly effect through all levels of the supply chain. If you make the moving parts in a machine lighter, the engines and gears can also be made smaller, which saves energy during operation and money for the operator. Lilium’s lightweight carbon fiber hull is essential for achieving electric-powered vertical takeoffs and landings. But it also obeys the general rule: the lighter the better.

A culture of innovation

Germany is a world leader in lightweight industries thanks to its great engineering tradition and because of the specialized companies and research institutes concentrated there. “Germany has the infrastructure and the experts in material design and technology to drive the Fourth Industrial Revolution,” says Dr. Rainer Müller, senior manager of lightweight technologies at GTAI. “You can’t create that from scratch – you’ve got to already have a tradition of engineering to be able to serve new industries.”

Facts & Figures

400 m

The investment by the U.S. aerospace giant Sierra Nevada Corp. in Germany to produce the Dornier 328*

28.2 bn

The total aviation turnover in Germany in 2018, not including spaceflight and defense**

*Source: Sierra Nevada Corp.
**Source: BDLI (German Aerospace Industries Association)

Lilium is one of many companies around the world that are rushing to create a flying taxi, but few have actually completed a successful test flight. The company’s location is strategic. Its founders met at the Technical University of Munich and decided to stay in Bavaria: “It made sense to remain here as the aerospace supply chain is strong throughout central Europe, and there’s a strong manufacturing base,” says spokesman Oliver Walker-Jones. The company is building the first of two factories that will employ hundreds of people once production is in full swing. Lilium aims to have its flying taxi hubs operational by 2025.

The strong supply chain was also a reason for U.S. aerospace giant Sierra Nevada Corporation to select Germany as the location for renewing production of the Dornier 328 passenger plane. The EUR 400 million investment will create the first new aerospace production facility in the former East Germany since the fall of the Berlin Wall.  Taking Off in Eastern Germany, page 8

Building new foundations

“I think we’re approaching a renaissance in the lightweight industries,” GTAI’s Rainer Müller says. “It’s not just about carbon composites. It’s also about high-performing metals and computer-driven materials research.”

Architecture also benefits from lightweight engineering’s ability to lower mass while maintaining strength. Reducing the weight of a ceiling, for example, makes it possible to redesign columns and walls because they need to support less weight. Considering all the intricate interdependencies and possibilities requires digital tools for planning and simulation. These types of calculations are too complex to be done with paper and pencil.

Exports flying high

Source: BDLI (German Aerospace Industries Association)

Researchers at the University of Stuttgart’s Institute for Computational Design and Construction (ICD) create experimental architecture projects, often inspired by nature and using robotic construction methods. The structures that the researchers are building might seem fanciful today, but the techniques and materials could one day become commonplace.

ICD researchers cooperated with local company FibR to create a pavilion for the 2019 Bundesgartenschau, a biennial German horticulture show. It was produced by two robotic arms spinning 150,000m of glass and carbon fibers. The resulting lightweight but sturdy structure was then covered by an ETFE (Ethylene Tetrafluoroethylene) membrane that’s both waterproof and recyclable. The finished pavilion looked like a futuristic circus tent, both alien and organic.

“I think that the sector of architecture and lightweight construction will grow because we are faced with the challenge of creating more housing and living space in cities for more and more people with fewer resources,” says Dr. Wolfgang Seeliger, managing director of Leichtbau BW GmbH, Baden-Württemberg’s development agency for lightweight innovation. “Lightweighting is the only way to cope with these challenges.”

Regional strengths

It’s no fluke that so many Leichtbau specialists can be found in southern Germany. Baden-Württemberg and Bavaria are renowned for their auto industries, which are currently facing the challenges of the shift to electric mobility. “One will find all stages of the value creation process here, from product concepts and designing methods to simulation and manufacturing,” explains Seeliger. “Customers from abroad often ask for solutions to reduce the costs of lightweighting, or they want to benefit from German manufacturing excellence when it comes to criteria like quality or process stability.”

Keeping weight down is of the utmost importance for electric vehicles. A lower weight will increase a car’s range without any increases in the size of its battery, which is not only expensive but adds additional weight. Using components made of hybrid plastic-metals or carbon composites can drastically reduce a vehicle’s overall mass.

Research & Development

Source: Federal Statistical Office

Auto companies are looking ahead to the not-too-distant future when autonomous vehicles will be commonplace. “A car needs a lot of sensors and systems to be able to drive alone,” says Seeliger. “And since, for safety reasons, many systems must be available redundantly in the vehicle, we can expect that the weight of a car will rise. By using lightweighting, you can compensate for the weight gain.”

Optimizing manufacturing

Although automobility and aerospace are the industries that most obviously gain from new lightweighting technologies, traditional manufacturing will also reap benefits. Digitalization is revolutionizing traditional production methods in what’s been termed Industrie 4.0 in Germany – the Fourth Industrial Revolution. The possibilities presented by a fully-digitalized factory – one that takes full advantage of innovative materials, artificial intelligence and computer-aided design – are yet to be realized.

In the case of Bahmüller, a family-owned mechanical engineering firm, the company used lightweight engineering to reduce the mass of a corrugated cardboard processing machine. They found that the carriage that moved the product batch through the machine during the operational cycle was the part with the greatest potential to optimize the machine’s functionality. Reducing the carriage weight led to being able to reduce the weight of the mounting frame as well (the frame had to meet specific requirements of strength and stiffness in order to absorb the machine’s vibrations). By reducing the moving mass in the machine, the amount of vibrations were reduced as well. Overall, Bahmüller was able to reduce the mass of the machine by 50 percent, while saving 25 percent on the cost of building it and 40 percent on energy use.

Automotive Industry

422.8 bn

Total turnover of the German auto industry in 2017 (up 4% on the previous year)

820,200

Employees working within the German auto industry in 2017 (up 1% on the previous year)

Source: 2017, VDA (German Association of the Automotive Industry)

In Stuttgart, the Fraunhofer Institute for Manufacturing Engineering and Automation (IPA) has developed a processing machine that can not only mill carbon fiber-reinforced plastics (CFRP) but also perform the post-processing. Cutting back on manual labor allows for post-processing savings of up to 50 percent and protects workers from harmful dust.

Carbon fiber-reinforced plastics are as stable as steel but eight times lighter. However, the manufacturing and processing costs of CFRP components have remained high because of the manual work required. Operators have to take freshly milled components from the machine, remove protruding fibers, and clean the items before sealing the edges.

The new machine developed by Fraunhofer IPA and its industrial partners solves this problem. When a near-net-shape CFRP component is fed into the machine, it is milled into the desired shape. A brush then removes all the protruding fibers, and nozzles blow the fine dust into an exhaust system. A sensor uses strip light projection to check the CFRP workpiece for defects.

Industry Growth Areas

If all measurements are within the tolerance range, the processing machine seals the edges with a liquid lacquer cured with ultraviolet light, and the component is ready. The system isn’t just limited to CFRP projects — it can also mill, finish and paint wood, aluminum or metal components.

Looking to the future

Unsurprisingly perhaps, more and more international companies are investing in German engineering. In November, Elon Musk announced plans to locate Tesla’s fourth Gigafactory for producing its electric cars, batteries and motors in Grünheide, Brandenburg, an hour southeast of Berlin. The multi-billion-euro Gigafactory should create 3,000 new jobs when the facility opens in 2021, and up to 8,000 when it is fully operational.

Musk had been searching for a European location for Tesla for years. Analysts suspected that it might end up in Germany because of its strong auto supply chain. “Germany builds great cars,” Tesla’s CEO Musk said at an awards ceremony in Berlin shortly before the Gigafactory was announced.

Tesla already had a German connection – it has sourced parts from ElringKlinger, an automotive supplier specializing in lightweight components, for years. Now ElringKlinger will also supply the cockpit cross-car beams for Tesla’s new SUV Y series produced in California. The company uses hydroforming and injection molding in a single step to produce lightweight, hybrid, plastic-metal components with both high dimensional accuracy and structural strength.

Lightweight construction solutions could also determine Germany’s future competitiveness when it comes to wind power. Most windmill rotor blades are currently made of fiberglass composites. The bigger the blades, the greater the energy output. Wind turbines have become a major product for carbon fiber-reinforced plastics manufacturers, with rotor blades measuring up to 90m being made. They need to be lightweight – not only to achieve maximum performance and aerodynamic efficiency but to make transportation and installation easier as well.

»Lightweighting is a game-changer technology.«

Dr. Wolfgang Seeliger,
Managing Director of Leichtbau BW GmbH

Industry leaders are waiting with baited breath to see what can be achieved when additive manufacturing is combined with lightweight technologies. 3D-printing technologies already reduce waste, cost and energy use compared to traditional manufacturing. The potential for experimental structures and extreme lightweighting is still being explored.

Because lightweight technologies are so diverse and affect so many industries, getting an overview of the entire ecosystem is a challenge. But Germany’s Federal Ministry for Economic Affairs and Energy hopes to make those connections easier with its Initiative Leichtbau, the Lightweighting Initiative.

The first ever lightweight-focused trade show, LightCon, will take place in Hannover in June 2020. It’s organized by Deutsche Messe AG with Composites United as technical partner. All materials – from carbon composites to high-performance metals to wood – will be represented, and the program includes product lifecycle and the possibilities for reducing environmental impact.

“Our network started looking into recycling opportunities and applying methods to reduce and reuse materials quite early on,” Composites United CEO Gunnar Merz says. “In the case of hybrid materials, you can only address recycling by getting all the partners together.” That kind of collaboration will hopefully continue all year round. Composites United regularly arranges tours of German facilities for overseas visitors and international tours for German delegations. “International cooperation is very important in this innovative field,” Merz says. “It’s hard to implement the newest developments when you do it alone.”

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