Further development of additive-generative manufacturing with regard to the production of large components
Duration: 01.09.2017 - 29.02.2020
Generative manufacturing processes already allow the production of complex, metallic components on a laboratory scale, which are increasingly being used in high-tech areas (e.g. aerospace). Despite the many advantages of these new technologies, such as freedom of design, the possibility of functional integration and the use of different materials, the acceptance of these processes has so far suffered, particularly in strongly cost-driven industries such as the automotive sector and rail vehicle technology, due to the comparatively low construction rates and the associated high production times and costs for large components. However, current demands for individualization, savings in operating resources and reduction of warehousing costs are also forcing industries traditionally dominated by steel construction, such as rail vehicle construction, to implement lightweight construction concepts, to combine component functionalities in larger integral components and to reduce the number of units due to individualization. Above all, this means an enormous increase in component complexity, which conventional production methods can in some cases hardly do justice to.
In the project, topology-optimized support structures on sidewall segments are produced additively and generatively by high-performance laser powder cladding (LPC). This combination should also make it possible to generate larger construction volumes in a production time that is competitive with conventional processes and also allow the implementation of lightweight construction concepts and functional integration.
The following work objectives were defined for the implementation of this ambitious project:
• Topology optimization and production-oriented design of a large component
In a topology-optimized design, a supporting structure is created by the interaction between construction and calculation, using a special calculation program, which takes into account the actual load courses and load values. This means that local under-utilization, which cannot be avoided in conventional structures due to production-related constant profile cross-sections and sheet thicknesses, can be reduced. Load-optimized structures are created which give an "organic" impression due to their appearance. With maximum utilization of this technology, considerable weight reductions are possible in load-bearing structures in some cases.
• Increase of the build-up rate of the LPC by 50 % compared to the state of the art
For the economic production of large components using LPC, an increase in the currently usual assembly rates is indispensable. The aim is therefore to scale up the process so that up to 50% higher build-up rates can be achieved compared to the current state of the art, which can significantly reduce the production time for large components.
• Development of plant technology for the additive-generative production of large components using high-performance LPC
The targeted build-up rates in the additive-generative production of large functional components by means of LPC and the associated energy and material flows place the highest demands on the system technology to be developed. In addition to the machine dynamics and repeat accuracy of the planned 5-axis positioning centre, which is necessary for the additive-generative production of complex structures, high demands are placed on the safety concept, which must take particular account of laser safety and the extraction of the excess powder, which is sometimes very hazardous to health.