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Browsing Conference Proceedings and Journals by Author "Abele, Eberhard"
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Item Dimensional Accuracy of Small Parts Manufactured by Micro Selective Laser Melting(University of Texas at Austin, 2016) Kniepkamp, Michael; Fischer, Jakob; Abele, EberhardWhile selective laser melting of metallic parts is already widely used in today’s industry, problems in this process still occur when using small parts with dimensions of less than 5 mm. Micro selective laser melting can fill gaps with layer sizes of less than 10 microns and powders with particle sizes smaller than 5 microns. In this paper the dimensional accuracy of parts with sub millimeter features using 316L steel powder is investigated. Test specimens with different features like slopes, overhangs and sharp radii were built applying different scan strategies. The parts were 3D scanned and compared to the CAD data to analyze their accuracy. Based on the results, optimized scan strategies for the different features were developed to increase the parts’ overall dimensional accuracy.Item Examination of the Connection Between Selective Laser-Melted Components of 316L Steel Powder on Conventionally Fabricated Base Bodies(University of Texas at Austin, 2018) Link, Martin; Haefele, Tobias; Abele, EberhardThe advantages of selective laser melting lie in the production of complex, small components in small batches. For large-volume components, the use of additive manufacturing (AM) processes is limited by the available installation space, low build rates, and high material costs. For the production of large and less complex workpieces, conventional manufacturing processes such as milling are more economical. The background of this study was to combine both processes to decrease manufacturing times. For this purpose, a body made of 316L (1.4404) steel powder was printed using selective laser melting on conventionally manufactured stainless-steel base bodies. The use of multi-materials enables optimized machinability in the respective manufacturing process. This paper examines the hardness properties of multi-material samples and uses micrographs to analyze the microstructure of their connection area. A complete connection between hybrid components made of comparable materials was determined.Item Fatigue Analysis in Selective Laser Melting: Review and Investigation of Thin-Walled Actuator Housings(University of Texas at Austin, 2014) Stoffregen, Hanns A.; Butterweck, Katja; Abele, EberhardThe versatile applicable selective laser melting (SLM) is a promising manufacturing technology that allows 3-dimensional design freedom for complex and challenging load bearing parts. A specific application of SLM is the production of thin-walled housings for piezoceramic actuators which induce cyclic loads. Although there are investigations on the fatigue behavior of SLM-specimens, wide acceptance of SLM is limited by a lack of knowledge concerning the operating behavior of actual parts. This paper presents a review on existing studies about fatigue life analysis in SLM as well as results from uniaxial high cycle fatigue (HCF) tests of 1.4542 stainless steel as-built and machined specimens with a stress ratio of R = 0. Due to a lower surface roughness machined specimens show significantly higher fatigue strength compared to as-built ones. The obtained fatigue strength at 107 cycles of as-built specimens is used as input for fatigue tests of thin-walled actuator housings. Numerical simulation is used to determine the stress distribution of thin-walled as-built actuator housings under specific loads. Results indicate that the thin-walled as-built actuator housing withstand higher peak stresses compared to as-built specimens due to a high stress gradient.Item Towards High Build Rates: Combining Different Layer Thickness within One Part in Selective Laser Melting(University of Texas at Austin, 2018) Kniepkamp, Michael; Harbig, Jana; Seyfert, Christoph; Abele, EberhardAdditive manufacturing of metallic parts using powder bed based fusion processes like selective laser melting is increasingly used in industrial applications. With typical layer thicknesses of 20 – 40 µm good surface qualities and high geometrical accuracy can be achieved compared to other AM processes. However, low layer thicknesses are to the detriment of build rates as more layers are required. Increasing the layer thickness can significantly increase build rates at the cost of surface quality and accuracy. In this paper a new parameter set for a layer thickness of 60 µm is developed and combinations of different layer thicknesses within one part are investigated. Thus increased build rates can be achieved while a high accuracy can be maintained when locally required. Specimens with combination of different layer thicknesses in various build orientations are produced and mechanically tested. Micrographs of the layer transitions are examined and recommendations for their design are given.