How lightweight design gives greater flexibility in automotive manufacturing

The vehicle bodies of tomorrow will not only need to be lighter, but above all will also require a highly flexible design. In the foreseeable future, additive manufacturing will be able to offer entirely new conceivable approaches

In a joint project, EDAG Engineering GmbH (Wiesbaden, Germany), Laser Zentrum Nord GmbH (Hamburg, Germany), Concept Laser GmbH (Lichtenfels, Germany) and the BLM Group (Cantù, Italy) presented the bionically optimized spaceframe produced by hybrid manufacturing to highlight a new way in which a bodywork concept that is adaptable and can be manufactured flexibly can be produced in order to make the increasing range of different vehicles manageable thanks to the large number of different drives and load stages.

Additively manufactured bodywork nodes and intelligently processed profiles are combined. Thanks to additive manufacturing, the nodes can be configured to be highly flexible and multifunctional so that, for example, different versions of a vehicle can be produced “on demand” without any additional tooling, equipment and start-up costs. Steel profiles are used as connecting elements. They too can easily be adapted on an individual basis to the specified load levels by providing them with different wall thicknesses and geometries.

The NextGen spaceframe is part of the EDAG “Light Cocoon” concept car, a compact sports car with a bionically configured and additively manufactured vehicle structure, covered with an outer skin made from a weatherproof textile material.

We spoke to all of the partners involved in the project about the new approach of a lightweight frame optimized for manufacturing.

Q. Is it becoming more difficult in the automotive sector to achieve the sustainability targets? If it is, what contribution is the hybrid NextGen spaceframe design from EDAG making?

Martin Hillebrecht: Automotive manufacturers are under great pressure to develop vehicles which are due to go into production between 2015 and 2020. The new bodywork structures should weigh less, have high stiffness to ensure outstanding performance and satisfy demanding load scenarios in the event of a crash. In spite of all the ambitious targets for weight reduction, greater demands from customers, thinking of alternative drives, comfort, functionality and networking, as well as new safety requirements from international legislators are sales criteria that do not favor lightweight construction. From my perspective, the core concept of a visionary and bionic spaceframe would be among other things only to use materials where they are really needed to deliver a function, safety or rigidity. So a reduced approach based on the motto “less is more”. Thanks to toolless additive manufacturing and the profiling method with minimal use of tools, it may even be possible in future to design all bodywork versions to suit the level of loading and manufacture them “on demand”. Whatever happens, there is definitely potential here.

Sergio Raso: Sustainability is the overriding aim for the automotive industry. Various core technologies for the future of automotive production have so far been looked at. The frame structure of the EDAG Light Cocoon combines many of these technologies in one approach. For example, there is a lightweight hybrid design to achieve weight reduction and fuel efficiency, use of additive methods for a bionically optimized design and use of tubing and profiles to ensure that the vehicle frame can be manufactured in a highly flexible way.

Q. As the example of electric vehicles in Europe demonstrates, it takes a long period of time to progress from initial innovators such as the pioneers Hayek (original Smart) or Tesla Motors (USA) to get to adapted innovations. Is the automotive industry really ready to look at its products in completely new ways?
Martin Hillebrecht: Experience shows that one possible way to embark on new manufacturing strategies such as lightweight design is often to produce small numbers of vehicles in the luxury car and supercar segment. This clientele identifies with lightweight design, e-mobility and technical innovations much more than the mass market. These “innovators” are willing to accept much higher manufacturing costs as a price worth paying for better driving dynamics, comfort, safety and for ecological reasons. If the technology displays suitable potential and as its development advances to allow mass automotive production, the processes can then be scaled up from a niche product to enable larger volumes to be produced. But this definitely requires a degree of patience, long-term investments in the future of the companies involved and a great deal of technical expertise. I don’t accept that “a long period of time” is required, but it definitely takes some time to adapt new technologies.

Sergio Raso: In the automotive industry, the number of jobs depends to a large degree on the manufacturing methods and strategy employed. They have a crucial bearing on the cost structures, the achievable margins and the level of success. These factors shape the way we look at mobility and not least also the prosperity of many national economies. In order to maintain the level of automotive mobility that has been achieved, the automotive industry has continuously invested in making technological advancements to its automobiles and the production processes behind them. Investments in research and development are essential, and we at the BLM Group are also on this path of innovation and ongoing development.

Q. Conservation of resources and “green technology” are key aspects. How does the automotive manufacturer view this?
Martin Hillebrecht: Thanks to smart lightweight design, particularly with composite construction, the vehicles should be roughly 100 kg lighter than their predecessors, depending on the segment of the market. A further weight saving of from 10 to 20% can be achieved in the bodywork and add-on parts. Many manufacturers have already succeeded in reversing the spiraling trend for increased weight. But what is also true is that in spite of all the ambitious targets for weight reduction, the greater demand from customers for alternative drives, comfort, functionality and networking as well as new safety requirements from international legislators are sales criteria that do not favor lightweight construction. It is a balancing act that we are trying to achieve.

Sergio Raso:  Solutions for “green technologies” and intelligent energy management are heavily dependent on action by governments, with their political targets, laws and definitely also the incentives that they provide. This focus, if we just look at the US state of California, is an increasingly prevalent fact that we must come to terms with. Automotive manufacturers are accepting these demands and also view political targets as an engine for driving innovation. So politicians and manufacturers share a common interest. Along with the known solutions for energy management, such as developing electric storage units and drives, and also vehicles equipped with fuel cells, the manufacturing processes can also be heavily geared to reflect the visions of “green technology”.

The manufacturing design with all-electric bending machines, laser cutting machines with a high level of efficiency or laser melting are examples of how the BLM Group is committed to a “greener” future. The path toward intelligent conservation of resources and sustainability is an irreversible mega trend. All of the stakeholders in the automotive industry are conscious of this.