Through the research of the DMRC a few innovations have been developed. These innovations appear in different fields of research and are presented in detail here.
For applications in electrical machines, AM provides exciting new possibilities. The process- specific freedom of design enables themeconomical production of geometrically complex components, since the component complexity has only a minor influence on the production costs.
Markings can be understood as a kind of individualization of parts. As individualization does not increase production costs when using AM the only effort results from the integration of markings in the digital product data.
Additive manufacturing (AM) of metal components attracts substantial attention. By employing AM, highly complex parts can be generated with additional functionalities such as contour near cooling, sensor systems, or permeable structures. With regard to selective laser melting filigree parts can be generated in a near net shape fashion. However, alloys processible via SLM are limited. Improved SLM manufacturing conditions can be achieved either by material adjustments consistent powder heating up to 800 °C.
Advantages of additive manufacturing using the example of functional integration of damped structures. Application example: armature plate in a spring-loaded brake.
The focus of the scientific work of the Chair of Design and Drive Technology (KAt) are electromechanical drive technology and design aspects in additive manufacturing processes. In the research project “KAtAMaran” (“Design and drive technology in an AM-optimized modular drive”), a modular multi-motor drive system (short: MMDS) is being developed as a research platform that exhibits the design freedom of additive manufacturing and the advantages of function integration.
Additive manufacturing processes are playing an increasingly important role in the field of medical technology. They make it possible to meet the demand and need for patient-specific products. The high design freedom of additive manufacturing processes in combination with CAE methods is used to provide approaches to solve the existing stiffness problem in hip endoprosthetics. Using stress adapted geometries and the finite element method, stiffness adapted variants of a short shaft hip endoprosthesis are developed in an iterative process.
The processing of metal powder filled polymer filaments in Fused Deposition Modeling (FDM) presents a comparatively new technology for the production of metal components. This technology enables powder-free handling of the base material and processing on low-cost FDM equipment. The aim of the research in cooperation with DMRC industrial consortium is to achieve a better understanding of the technology throughout the entire process chain.
Technical and economic feasibility study for the use of the SLM process for a hydraulic clamping device. A high weight saving could be achieved by topology optimization.
The laser-sintering process has, beside all the advantages like a high productivity and a great design freedom, significant disadvantages with the low material variety and material ageing. A major proportion of all LS components are still made of PA12 and PA11. High performance materials e.g. PA6, PPS, PEKK, etc. are appearing increasingly on the market but they cannot be processed on standard LS systems due to the higher processing temperature.
Temperature effects in the polymer laser sintering process are an important aspect regarding the process reproducibility and part quality. Depending on the job layout and position within the part cake, individual temperature histories occur during the process.
Experience from conventional manufacturing shows a good performance of the high-strength aluminum alloy EN AW 7075 which leads to frequent use in automotive and aerospace sector. Scientific investigations on the processability of this alloy in the SLM process shows that prepared samples have anisotropic behavior due to process-induced hot cracks. Furthermore, it was not possible to determine solid results regarding the fracture mechanical characterization.
A design adjustment of the inner structure minimizes the floating overhangs in the range of the flow channels. Due to this adjustment, the use of any kind of support material can be avoided. In this way it can be ensured that no residues of water soluble or non-biocompatible material remain in the system.
The layered structure of Additive Manufacturing processes results in a stair-stepping effect of the surface topographies. In general, the impact of this effect strongly depends on the build angle of a surface whereas the overall surface roughness is caused by the resolution of the specifi c AM process. The aim of this work is the prediction of surface quality in dependence of the part building orientation.
Machine and part qualification are always based on the information gathered. For a proper qualification and for confidence gaining in the LS technology the process itself should be observed and monitored as precisely as possible. Within this DMRC project a high-resolution images-based powder spread monitoring system for the laser sintering process has been developed.
A component is created in the Fused Deposition Modeling (FDM) process by depositing a polymer strand layer by layer. Due to thermal fusion, the deposited material bonds with the layer below. This leads to the characteristic welded seams of the FDM process. Therefore, an essential part of the qualification of new materials for the FDM process is the evaluation of the processing suitability by means of the weld seam quality.
