Riede Mirko, Knoll Matthias, Wilsnack Christoph, Gruber Samira, Alegre Cubillo Alba, Melzer Christian, Brandão Ana, Pambaguian Laurent, Seidel André, Lopez Elena, Brueckner Frank, Leyens Christoph
Fraunhofer Institute for Material and Beam Technology IWS, Winterbergstraße 28, 01277 Dresden, Germany.
Institute of Materials Science, Technische Universität Dresden, Helmholtzstr. 7, 01069 Dresden, Germany.
Materials (Basel). 2019 Jul 30;12(15):2426. doi: 10.3390/ma12152426.
Recently, additive manufacturing (AM) by laser metal deposition (LMD) has become a key technology for fabricating highly complex parts without any support structures. Compared to the well-known powder bed fusion process, LMD enhances manufacturing possibilities to overcome AM-specific challenges such as process inherent porosity, minor build rates, and limited part size. Moreover, the advantages aforementioned combined with conventional machining enable novel manufacturing approaches in various fields of applications. Within this contribution, the additive manufacturing of filigree flexure pivots using 316L-Si by means of LMD with powder is presented. Frictionless flexure pivot bearings are used in space mechanisms that require high reliability, accuracy, and technical cleanliness. As a contribution to part qualification, the manufacturing process, powder material, and fabricated specimens were investigated in a comprehensive manner. Due to its major impact on the process, the chemical powder composition was characterized in detail by energy dispersive X-ray spectroscopy (EDX) and inductively coupled plasma optical emission spectrometry (ICP-OES). Moreover, a profound characterization of the powder morphology and flowability was carried out using scanning electron microscopy (SEM) and novel rheological investigation techniques. Furthermore, quantitative image analysis, mechanical testing, laser scanning microscopy, and 3D shape measurement of manufactured specimens were conducted. As a result, the gained knowledge was applied for the AM-specific redesign of the flexure pivot. Finally, a qualified flexure pivot has been manufactured in a hybrid manner to subsequently ensure its long-term durability in a lifetime test bench.
最近，通过激光金属沉积（LMD）进行的增材制造（AM）已成为制造高度复杂零件且无需任何支撑结构的关键技术。与众所周知的粉末床熔融工艺相比，LMD增强了制造可能性，以克服增材制造特有的挑战，如工艺固有孔隙率、较低的构建速率和有限的零件尺寸。此外，上述优势与传统加工相结合，在各个应用领域实现了新颖的制造方法。在本论文中，介绍了使用316L-Si通过带粉末的LMD增材制造细丝挠性枢轴的方法。无摩擦挠性枢轴轴承用于需要高可靠性、高精度和技术清洁度的空间机构中。作为零件鉴定的一项工作，对制造工艺、粉末材料和制造的试样进行了全面研究。由于其对工艺的重大影响，通过能量色散X射线光谱法（EDX）和电感耦合等离子体发射光谱法（ICP-OES）对化学粉末成分进行了详细表征。此外，使用扫描电子显微镜（SEM）和新型流变学研究技术对粉末形态和流动性进行了深入表征。此外，还对制造的试样进行了定量图像分析、力学测试、激光扫描显微镜和三维形状测量。结果，所获得的知识被应用于挠性枢轴的增材制造特定重新设计。最后，以混合方式制造了一个合格的挠性枢轴，随后在寿命试验台上确保其长期耐用性。
