3D printing metal in the automotive industry: you need to start small

EDAG, Voestalpine, and Simufact have developed the lightHinge + engine hood loop using the potential of additive manufacturing. The components were manufactured at the Voestalpine Additive Production Center on a metal 3D-printer SLM 280 with two lasers (selective laser melting technology). The result: weight reduction, material savings and functional integration.

Current situation and tasks

Active loopback systems for engine hoods are very complex due to their strict safety and functionality requirements. In a traffic accident involving a pedestrian, they increase the distance between the object with which the collision occurs and the hard engine components by raising the engine hood. The pyrotechnic actuator operates in a split second and raises the hood.

With mass production of more than 30 thousand units per year, such loopback systems can be manufactured by stamping, casting or pressing. Due to the complex kinematics, a large number of individual parts is required (about 40 components for each vehicle) and high costs for assembly and production of equipment. In the manufacture of active loops of sheet metal, each loop weighs about 1500 g, which leads to a significant weighting of the car.

SLM technology has reduced the mass of the product by 52% and reduced the number of components by 68% compared to the original sheet metal design

At the same time, the existing economic restrictions do not allow to cover the costs of small-scale production from 80 to 30 thousand units per year, using mass production technologies. Moreover, in the case of sports cars, the design of the car and the lack of space for assembly in its front end, as a rule, exclude the possibility of making active engine hood loops from sheet metal.

Bypass strategies designed to minimize investment in small-scale production usually entail problems with packaging and design, coupled with the adaptation of mass production processes of active loops. Thus, the joint project of EDAG, the Center for Additive Production of Voestalpine and Simufact was intended to use the potential of additive manufacturing to solve these problems.

Solution: 3D Metal Printing


From the very beginning, great demands were placed on the bonnet hinge: it was necessary to fulfill the requirements for strength and rigidity with the greatest possible reduction in weight. It was also important to carry out functional integration with a corresponding reduction in the number of components.

First, a topological optimization was carried out, which included the calculation of the minimum material requirements based on the actual loads. Complex geometric shapes resulting from this process can usually be realized only with the help of laser melting technology using a variety of supports. In the LightHinge + project, the share of subsequently removed supports should have been about 50% of the total volume of the material to be melted. In the course of joint work, this figure was consistently reduced, first to 30% and then to 18%. Thereby, a significant part of processing operations was eliminated and high efficiency of using materials was ensured.

Although topological optimization required significant design changes to reduce post-processing, the end result provided a weight reduction of 52% compared with the original sheet metal design due to the application of bionic principles.

Engine hood loop created in an additive way (left) and made of sheet metal (right) / EDAG photo

Minimizing the number of supports with a decrease in their share in the volume of material from more than 50% (left) to less than 30% / Photo EDAG

Functional integration

This loop was also required to provide an automatic hood opening function. Freedom of design, which gives the additive production, allowed EDAG engineers to develop complex structures with predetermined break points. In addition, the loop was able to integrate the point of connection of the gas spring, the mounting for the wiper tube and the screw with the collar. This functional integration reduced the number of components by 68% compared with the original sheet metal part, significantly reducing the initial mass of the structure. In such an integrated version, this loop can be installed in a limited space of sports and other vehicles with high performance requirements.

Simufact Additive Software

Comparison of the state before and after the deformation compensation in the lower part: deformation relative to the CAD model (left); deformation of the compensated component according to the simulation results (right) / Photo by Simufact

Concentrated heat supply during the process of additive production leads to deformation and the appearance of internal stresses due to rapid heating and cooling. As measurements have shown, without compensation for deformation, this may lead to a 1-2 mm deviation of the loop size from the CAD model. Because of this, an important intermediate step in the development and production of components in an additive way is to simulate the actual laser melting process. For this purpose, the software has been used by Simufact Additive, developed specifically for additive manufacturing. This software allows you to simulate the process of 3D printing and the subsequent processing steps, predicting the appearance of deformations and internal stresses.

The modeling of the building process played a critical role in improving the design, improving safety and optimizing the deformation of the additively produced loop. The use of Simufact Additive software has made it possible to reduce the amount of deformation of the hood loop as a whole by about 80%. It also made it possible to do without carrying out costly and time-consuming production tests, since the components produced were within the required tolerance from the very first production batch.

Project participants

The LightHinge + project was awarded the German Innovation Award 2018 in the category "Achievements in the field of B2B – automotive technology"

LightHinge + is a joint project of three companies.

  1. EDAG Engineering GmbH is an independent engineering service provider for the global automotive industry. As a leader in technology and innovation, EDAG also manages a number of innovation centers set up by it, which develop innovative technologies for the automotive industry: lightweight structures, electric vehicles, automotive information technologies, integrated safety solutions and new manufacturing technologies.
  2. The Voestalpine GmbH additive manufacturing center is part of the Voestalpine Group of Companies – a global leader in technology and capital goods with a unique combination of expertise in materials and processing. In 2016, a new research center for 3D printing of metal parts for the aviation and aerospace industry, automotive industry, tool manufacturing, etc. was opened at the Voestalpine Group premises in Düsseldorf.
  3. Simufact Engineering is an international software development company headquartered in Hamburg (Germany). Develops software solutions for designing and optimizing production processes using process modeling. The solutions in the field of modeling from the company Simufact builds the work of the departments of development, design and production of many well-known companies.

Results: briefly

  • Strict safety requirements and complex design – weight reduction of 52% compared with the original sheet metal construction.
  • Functional integration has reduced the number of components by 68% compared to the original part.
  • Holistic approach to the development of parts, which takes into account the entire technological chain of additive production.
  • Minimizing the number of supports leading to a reduction in material consumption and the number of post-processing processes required.

Material provided by SLM Solutions

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