3D Printing Germany: Light-Weight Construction and Flexibility
Manufacturers are currently required to integrate the increasing number of drive concepts and energy storage systems into vehicle structures.
The vehicle bodies of tomorrow, particularly in view of alternative drive systems in small series with lots of different versions, will not only need to be lighter, but above all will also require a highly flexible design. The consequence is an increasing number of vehicle derivatives which demand adaptable bodywork concepts that are economical to manufacture. In the foreseeable future, additive manufacturing could offer entirely new possible approaches.
The Edag concept car ‘Light Cocoon’ is a compact sports car with a bionically designed and additively manufactured vehicle structure, covered with an outer skin made from weatherproof textile material. The Edag Light Cocoon was unveiled in March 2015 at the Geneva Motor Show and in September 2015 at the International Motor Show (IAA) in Frankfurt. It is intended to polarize opinions among designers and breaks open existing thought patterns in vehicle design. The bodywork structure embraces bionic patterns and translates them into a lightweight bodywork structure—a concept car that highlights sustainable approaches and at the same time embodies the technological potential of additive manufacturing.
Production of the Additively Manufactured Nodes
The LaserCusing process from Concept Laser generates components in layers directly from 3D CAD data. This method allows the production of components with complex geometrical shapes without the use of any tools. It is possible to produce components which would be very difficult or impossible to fabricate by conventional manufacturing. With this type of design, the nodes cannot be manufactured by conventional steel casting. In order to be able to guarantee a fault-free structure, a support structure should be provided on planes with an angle of less than 45 degrees in relation to the build platform. As well as providing simple support, the support itself absorbs in particular internal stresses and prevents the components from warping. Due to the complex geometry of the nodes, clean support preparation is the absolute basis of successful production. After preparing the support, the component is virtually cut into individual slices. Once the data has been transferred to the LaserCusing machine, the corresponding process parameters are assigned, and the build process is started. The nodes were manufactured on an X line 1000R machine from Concept Laser which has the appropriate build envelope (630 x 400 x 500 mm3) for such projects and operates with a 1kW laser. Only the new X line 2000R (800 x 400 x 500 mm3), likewise from Concept Laser, has a larger build envelope for powder-bed-based laser melting with metals and it is also equipped with 2 x 1kW lasers.
Digital 3D manufacturing strategy
The spaceframe concept combines the advantages of 3D printing, such as flexibility and the potential for lightweight construction, with the efficiency of proven conventional profile designs. The laser plays the key role in both technologies. The topologically optimized nodes enable the maximum lightweight construction that is possible at the present time, and a high degree of functional integration. Both the nodes and the profiles can be adapted to new geometries and load requirements without any additional outlay. This means that they offer the possibility of designing every single part to cater for the level of loading, and not dimensioning the components to reflect the greatest motorization or load stage, as was previously the case. The basic idea then is to have a node/profile design which can be optimally customized to reflect what the particular model requires. The result is a spaceframe structure with an optimized load path. By employing processes that do not involve much use of apparatus or tools, it will be possible in future to manufacture all bodywork versions economically and with the greatest possible flexibility.