Abstract
Laser powder bed fusion (L-PBF) has been the most popular metal additive manufacturing (AM) process thus far. However, residual deformation of the metal builds has been a significant issue. Laser scanning strategies adopted in the laser-assisted fabricating process have proved to have important influence on the residual stress and deformation. As the main contribution of this paper, the effects of different laser scanning strategies are incorporated into the modified inherent strain modeling (MISM) framework for the first time to enable accurate simulation for residual deformation of the L-PBF metal parts. Anisotropy in mechanical property of the fabricated components caused by the laser scanning strategies is also fully considered. For the rotational laser scanning strategies, only a small-scale representative volume element (RVE) is modeled by employing both the inherent strains and asymptotic homogenization. By employing the homogenized inherent strains, residual deformation can be predicted for the L-PBF manufactured components using different rotational scanning strategies accurately. Regarding the unidirectional parallel line scanning strategy, the directional inherent strain vector and orthotropic mechanical properties are used in the MISM-based layer-wise simulation. Good accuracy of the proposed framework is fully validated through comparing the simulated residual deformations with the experimental results for Inconel 718 parts produced by different laser scanning strategies. Thus, it is demonstrated that the effects of both parallel line and rotational laser scanning strategies have been successfully integrated into the MISM framework for predicting residual deformations of the L-PBF builds.
| Original language | English |
|---|---|
| Article number | 101648 |
| Journal | Additive Manufacturing |
| Volume | 37 |
| DOIs | |
| State | Published - Jan 2021 |
| Externally published | Yes |
Funding
The authors want to gratefully acknowledge financial support provided by the NASA STTR, USA program. We also want to thank Andrew Holmes in the Swanson Center for Product Innovation (SCPI) of University of Pittsburgh given his generous help in the 3D laser scanning experiments. The authors confirm that they have no conflicts of interest to clarify for this work. One of the authors of this article is part of the Editorial Board of the journal. To avoid potential conflicts of interest, the responsibility for the editorial and peer-review process of this article lies with the journal's other editors. Furthermore, the authors of this article were removed from the peer review process and had no, and will not have any access to confidential information related to the editorial process of this article. The authors want to gratefully acknowledge financial support provided by the NASA STTR , USA program. We also want to thank Andrew Holmes in the Swanson Center for Product Innovation (SCPI) of University of Pittsburgh given his generous help in the 3D laser scanning experiments.
| Funders | Funder number |
|---|---|
| Andrew Holmes in the Swanson Center for Product Innovation | |
| NASA STTR | |
| SCPI |
Keywords
- Homogenization
- Inherent strain
- Laser scanning strategy
- Material property anisotropy
- Residual deformation
