TY - CHAP A1 - Sommer, David A1 - Hornung, Simon A1 - Esen, Cemal A1 - Hellmann, Ralf ED - Gu, Bo ED - Chen, Hongqiang T1 - Optimization of mechanical properties of additive manufactured IN 718 parts combining LPBF and in-situ high-speed milling T2 - Laser 3D Manufacturing XI KW - Hybrid additive manufacturing KW - High-speed Milling KW - Hot isostatic pressing KW - Fatigue behaviour KW - Hochgeschwindigkeitsfräsen Y1 - 2024 U6 - https://doi.org/http://dx.doi.org/10.1117/12.3000952 PB - SPIE ER - TY - JOUR A1 - Sommer, David A1 - Hornung, Simon A1 - Esen, Cemal A1 - Hellmann, Ralf T1 - Surface roughness optimization of hybrid PBF-LB/M-built Inconel 718 using in situ high-speed milling JF - The International Journal of Advanced Manufacturing Technology N2 - AbstractWe report on the optimization of the surface roughness of hybrid additive manufactured Ni superalloys, combining a conventional laser powder bed fusion process with in situ high-speed milling. This remarkable hybrid approach has only recently been applied to different steel types and barely to Ni superalloys which opposite to steel appear to be challenging for milling processes, particularly within the powderbed of laser powder bed fusion. Different influencing factors on the surface roughness are varied in this study, following the Taguchi method. Their effect is evaluated with respect to the average surface roughness and the maximum surface roughness. The signal-to-noise ratio for the varied parameters infeed, z-pitch, feed rate, and spindle speed is calculated, determining their relevance on the surface roughness, and defining an optimal parameter combination. As the surface quality is optimized to $$\varvec{R_a=0.47\, \mu m}$$ R a = 0.47 μ m , the definition of the optimal parameter combination is of the highest relevance for the application of this novel manufacturing approach for Inconel. Using linear regression, the resulting surface roughness of these parameters is predicted, getting validated by the experimental evaluation. Due to a further analysis, including EDX analysis and a quantitative element analysis at different positions of the flank of the milling cutter, wear characteristics as well as the dissipation of the coating of the milling cutter are detected. The flank wear and the resulting breakage of the cutting edge are defined as the main reasons of a rising surface roughness. KW - Hybrid additive manufacturing KW - High-speed Milling KW - Taguchi-Method KW - Hochgeschwindigkeitsfräsen Y1 - 2024 U6 - https://doi.org/http://dx.doi.org/10.1007/s00170-024-13382-5 SN - 0268-3768 VL - 132 IS - 3-4 SP - 1741 EP - 1751 PB - Springer Science and Business Media LLC ER - TY - JOUR A1 - Sommer, David A1 - Esen, Cemal A1 - Hellmann, Ralf T1 - Static and Dynamic Mechanical Behaviour of Hybrid-PBF-LB/M-Built and Hot Isostatic Pressed Lattice Structures JF - Mechanical Properties of Polymeric, Metallic, and Composite Materials N2 - We report on a comprehensive study of the mechanical properties of maraging steel body-centred cubic lattice structures fabricated by a hybrid additive manufacturing technology that combines laser powder bed fusion with in situ high-speed milling. As the mechanical properties of additive manufactured components are inferior to, e.g., cast components, surface modifications can improve the mechanical behaviour. Different hybrid additive manufacturing technologies have been designed using additive and subtractive processes, improving process quality. Following this, mechanical testing is performed with respect to static tensile properties and dynamic stress, hardness, and porosity, comparing specimens manufactured by laser powder bed fusion only to those manufactured by the hybrid approach. In addition, the influence of different heat-treatment techniques on the mechanical behaviour of the lattice structures is investigated, namely solution and aging treatment as well as hot isostatic pressing. Thus, the influence of the superior surface quality due to the hybrid approach is evaluated, leading to, e.g., an offset of about 14–16% for the static testing of HIP lattice structures. Furthermore, the dynamic load behaviour can be improved with a finished surface, heading to a shift of the different zones of fatigue behaviour in the testing of hybrid-built specimens. KW - Hybrid additive manufacturing KW - Lattice structures KW - Hot isostatic pressing KW - Fatigue behaviour KW - Isostatisches Heißpressen KW - Selektives Laserschmelzen Y1 - 2023 UR - https://www.mdpi.com/1996-1944/16/9/3556 U6 - https://doi.org/https://doi.org/10.3390/ma16093556 VL - 16 IS - 9 SP - 1 EP - 14 ER -