| 1. |
- Deckers, Tobias, et al.
(författare)
-
Einfluss heliumhaltiger Prozess-gase auf den Laser-Strahlschmelz-prozess
- 2022
-
Ingår i: Zeitschrift Kunststofftechnik. - : Walter de Gruyter GmbH. - 1864-2217. ; 117:7-8, s. 452-455
-
Tidskriftsartikel (refereegranskat)abstract
- Influence of Process Gases Containing Helium on the Laser Beam Melting Process. Can the process gas play a key role in optimizing the PBF-LB/M process (layer thickness, scan speed, processability of new materials, etc.)? This article provide insights into the current state of research at Linde GmbH regarding he-lium-containing process gases and presenting the novel process gas ADDvance® Laser230. Due to its composition, the gas mixture allows to significantly improve process productivity and stability.
|
|
| 2. |
- Deckers, Tobias, et al.
(författare)
-
Impact of processing gas composition on process stability and properties of PBF-LB/M processed alloy 718
- 2024
-
Ingår i: Journal of Manufacturing Processes. - 1526-6125. ; 120, s. 712-718
-
Tidskriftsartikel (refereegranskat)abstract
- The almost unlimited design freedom of the laser-based powder bed fusion of metals (PBF-LB/M) makes this technology very attractive for industry. However, as a developing technology, it still faces some challenges when it comes to productivity and robustness, to name some. Whereas numerous studies covered the impact of laser-based parameters on material properties and robustness, the effect of the processing gas received limited attention. The objective of this study was to evaluate the effect of processing gas composition, containing helium (He) and hydrogen (H2), compared to conventionally used argon (Ar), during PBF-LB/M processing of virgin alloy 718 powder, on printing behavior and part properties. The four gases studied were Ar, Ar +30%He, Ar +30%He +2%H2, and Ar +70%He. Optical Tomography (OT) was used to monitor process stability, which unveiled a significant decrease in process-by products (spatters) between 51 % and 89 % using He and H2-containing gases. It was also found that the process gas decreased the bulk porosity from an average value of 0.08 % when processed with Ar to 0.04 % when using Ar + 70%He. The oxygen pickup by the spatter particles was reduced from 630 ppm (Ar) to 331 ppm (Ar +70%He). EBSD analysis revealed that there were no evident changes in microstructure with the processing gas. The samples processed also had similar tensile properties with yield and ultimate tensile strength of 1180 MPa and 1395 MPa, respectively. However, there was a slight increase in ductility from 16.5 % to 17.2 %, when processed with pure Ar and Ar + 70%He, respectively. This study shows that utilizing standard Ar processing atmosphere with He addition leads to a more stable process with reduced spatter, porosity and a marginal increase in ductility for Alloy 718.
|
|
| 3. |
- Zissel, Kai, 1995, et al.
(författare)
-
Binder Jetting - Reusability of 17-4 PH Stainless Steel Powder
- 2022
-
Ingår i: World PM 2022 Congress Proceedings.
-
Konferensbidrag (refereegranskat)abstract
- Binder Jetting (BJT) is a binder-based Additive Manufacturing technology, where only a small fraction of the processed powder is bonded inside the green parts after printing. Unbound powder, which is recovered during the BJT process, is reused for printing. For powder reuse, the resulting changes in the physical and chemical powder properties along with the powder surface conditions strongly affect the reproducibility of the BJT process and its final part properties. In this study, the powder degradation and its impact on the reusability of 17-4 PH stainless steel powder are evaluated for the BJT process. Powder characteristics are analyzed after multiple reuse cycles after different process steps, namely drying, sieving, printing and curing. The influence of reused powder on print quality and green densities is investigated and compared to virgin powder. Furthermore, the effect of inert and reducing atmospheres on the powder reusability during curing is examined.
|
|
