EDAG LIGHTHINGE+ PROJECT, MODERN BONNET HINGE SYSTEM IN ORGANIC DESIGN
That's why with Edag LightHinge+ project we aimed to develop the lightest possible technical solution for the active bonnet hinge with the help of additive production technologies. We want to offer a part that does not require millions in initial production costs, but to have a piece price of less than 500 Euros.
In the first phase we devised a design that came from defining the course of forces in the original part with the engine bonnet open. Shape optimization of the resulting mass allowed us to reduce the weight as well as the number of components. We managed to get from 19 down to 6 parts and thus shorten the required assembly time by 68%. Using the Direct Metal Laser Sintering (DMLS) technology we achieved a target weight of 770 grams per hinge which means a weight reduction of 51%.
Direct Metal Laser Sintering, as the name suggests, sinters metal powder using a laser beam. It is one of a number of technologies where the product is not created by removing material but conversely the material is layed in very thin layers on exactly defined places. The disadvantage of this technology is the need for printing supports. The optimization phase has several stages. In the first stage Edag and its partners managed to reduce the percentage of needed supports from the original 50% of the total volume down to 30% by further adjusting the design of the parts and then down to the final 18% by optimizing the supports themselves.
The next phase was the realization of the final prototypes on which actual mechanical strenght tests were done in cooperation with company Voestalpine. Several samples with different structures were printed and mechanically tested. We found that because of the concentration and speeds of the thermal inputs the hinge naturaly twists resulting in an inaccuracy from the design of about 1-2mm. In the subsequent calibration it was therefore necessary to simulate the print process to predict the shape distortion based on a simulated manufacturing process. On the basis of these findings it was necessary to pre-deform the production data so that the deviation of the hinge print from the design was as small as possible.
Edag and its partners Voestalpine Additive Manufacturing Center, Düsseldorf and Simufact Engineering have been able to develop a safer and cheaper product for small-scale production with the potential to be marketed within 3 years by utilizing design, topological optimization, piece work and additive technology to their full potential. The project has received several very important awards. For example in 2018 the MATERIALICA Gold Award in the CO2-efficiency category or another Gold at Innovation 2018 in Germany in the "Excellence in Business to Business" category.
"We are very proud to have received this award and we consider this to be a testimony of the innovative focus of our engineering services and a reference to the additive production we have devoted years of research and development into," Dr. Martin Hillebrecht, Head of the EDAG Fulda Competence Center, and the initiator of the award-winning LightHinge+ project.