Schleifende Nachbearbeitung additiv gefertigter austenitischer Edelstähle

Int J Adv Manuf Technol

Gutzeit

Hotz

et al. 2020

Self Cite

In selective laser melting (SLM) the variation of process parameters significantly impacts the resulting workpiece characteristics. In this study, AISI 316L was manufactured by SLM with varying laser power, layer thickness, and hatch spacing. Contrary to most studies, the input energy density was kept constant for all variations by adjusting the scanning speed. The varied parameters were evaluated at two different input energy densities. The investigations reveal that a constant energy density with varying laser parameters results into considerable differences of the workpieces' roughness, density, and microhardness. The density and the microhardness of the manufactured components can be improved by selecting appropriate parameters of the laser power, the layer thickness, and the hatch spacing. For this reason, the input energy density alone is no indicator for the resulting workpiece characteristics, but rather the ratio of scanning speed, layer thickness, or hatch spacing to laser power. Furthermore, it was found that the microhardness of an additively manufactured material correlates with its relative density. In the parameter study presented in this paper, relative densities of the additively manufactured workpieces of up to 99.9% were achieved.

Section: Microhardnesssupporting

confidence: 84%

Selective laser melting (SLM) of AISI 316L—impact of laser power, layer thickness, and hatch spacing on roughness, density, and microhardness at constant input energy density

Int J Adv Manuf Technol

Gutzeit

Hotz

et al. 2020

Self Cite

“…The microstructure of AM1 showed large pores, which is also evident from the relative density of ρ = 79.0% (σ ρ = 1.3%). The hardness of AM1 was 258 ± 12 HV 0.01 which is much higher than the hardness of the reference material (218 ± 17 HV 0.01 [24]). The roughness of the as-built AM1 surface was Ra = 7.4 μm (σ Ra = 7.6%).…”

Section: Characterization Of Am Workpiecesmentioning

confidence: 69%

Micro milling of additively manufactured AISI 316L: impact of the layerwise microstructure on the process results

Int J Adv Manuf Technol

Kieren-Ehses

Kirsch

et al. 2020

Self Cite

In the field of metal additive manufacturing (AM), one of the most used methods is selective laser melting (SLM)—building components layer by layer in a powder bed via laser. The process of SLM is defined by several parameters like laser power, laser scanning speed, hatch spacing, or layer thickness. The manufacturing of small components via AM is very difficult as it sets high demands on the powder to be used and on the SLM process in general. Hence, SLM with subsequent micromilling is a suitable method for the production of microstructured, additively manufactured components. One application for this kind of components is microstructured implants which are typically unique and therefore well suited for additive manufacturing. In order to enable the micromachining of additively manufactured materials, the influence of the special properties of the additive manufactured material on micromilling processes needs to be investigated. In this research, a detailed characterization of additive manufactured workpieces made of AISI 316L is shown. Further, the impact of the process parameters and the build-up direction defined during SLM on the workpiece properties is investigated. The resulting impact of the workpiece properties on micromilling is analyzed and rated on the basis of process forces, burr formation, surface roughness, and tool wear. Significant differences in the results of micromilling were found depending on the geometry of the melt paths generated during SLM.

“…As additive manufacturing offers a high potential to produce safety relevant structural components, where a sound knowledge of the cyclic properties is indispensable, the presented work focuses on the fatigue behavior of specimens manufactured by laser‐based powder bed fusion. In accordance with preliminary own work, the commonly used austenitic stainless steel AISI 316L was utilized as investigated material [19–22, 26, 27, 35]. Because the “as‐built” surface of additively manufactured parts leads to a dramatic decrease of fatigue strength and additive manufacturing only offers a low level of dimensional accuracy, subtractive manufacturing of additively manufactured parts is of great interest.…”

Section: Introductionmentioning

confidence: 99%

“…The most common post‐processing technology that is used in combination with additive manufacturing is machining [24]. Thereby, grinding and milling are suitable subtractive processes to significantly reduce the surface roughness of additively manufactured structures [25–27].…”

Section: Introductionmentioning

confidence: 99%

Influence of microstructural defects and the surface topography on the fatigue behavior of “additively‐subtractively” manufactured specimens made of AISI 316L

Blinn

Materialwissenschaft Werkst

Smaga

et al. 2021

As additive manufacturing offers only low surface quality, a subsequent machining of functional and highly loaded areas is required. Thus, a sound knowledge of the interrelation between the additive and subtractive manufacturing process as well as the resulting mechanical properties is indispensable. In this work, specimens were manufactured by using laser‐based powder bed fusion (L‐PBF) with substantially different sets of process parameters as well as subsequent grinding (G) or milling (M). Despite the substantially different surface topographies, the fatigue tests revealed only a slight influence of the subtractive manufacturing on the fatigue behavior, whereas the different laser‐based powder bed fusion process parameters led to pronounced changes in fatigue strength. In contrast, a significant influence of subtractive finishing on the fatigue properties of the defect‐free continuously cast (CC) reference specimens was observed. This can be explained by a dominating influence of process‐induced defects in laser‐based powder bed fusion material, which overruled the influence of surface machining. However, although both laser‐based powder bed fusion parameter sets resulted in substantial defects, one set yielded similar fatigue strength compared to continuously cast specimens.