Registration and fusion of large-scale melt pool temperature and morphology monitoring data demonstrated for surface topography prediction in LPBF

Zhang, Haolin; Vallabh, Chaitanya Krishna Prasad; Zhao, Xiayun

doi:10.1016/j.addma.2022.103075

Cited by 10 publications

(6 citation statements)

References 33 publications

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“…Micro hardness of the grains for all the combinations of parameters varies from 325 to 395 HV, 20 comparable to the values reported in literature with samples fabricated using uniform parameters. 22 Unfortunately the exact value can't be obtained because it is hard to find the parameter set for the current location due to grinding and the thin layer of each parameter set.…”

Section: Microstructuresupporting

confidence: 87%

“…The effect of laser power, scanning speed and the derived laser energy density on microstructure and voids were investigated in reference. 20 However, the microstructure observation is still limited to few horizontal and vertical sections. In this paper, sample No.…”

Section: Methodsmentioning

confidence: 99%

“…Macrostructure and microstructure was performed under SEM and optical microscope, and micro hardness was tested, these results were published in reference. 20 The microstructural analyze was further conducted using a FEI Helios G4 PFIB CXe microscope. The sample was sliced with a thickness of 1µm by xenon ion beam, which is of high micro-milling speed.…”

Section: Methodsmentioning

confidence: 99%

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3D characterization of the microstructure of LPBF- fabricated Inconel 718 alloy

Kang¹,

Huangb²,

Yub³

2023

MSEIJ

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Laser powder bed fusion method is popularly applied in the additive manufacturing of metal parts. The void defect and microstructure are the main factors which determine their mechanical properties. However, the characterization of microstructure and cavities is two dimensional, which is hard to show the spatial profile. In this paper, in order to explore the microstructure and defects in three dimensions, the combined continuously slicing and microstructure observation was used to investigate the microstructure of an Inconel 718 sample. The sample was sliced 468 layers with thickness of 1 µm by xenon ion beam, a 142.8 µm* 107 µm* 46.8 µm microstructure cube was reconstructed. From the 3D model, the melt pool, cavity, pore and grains and their orientations were analyzed. The results provide spatial features of its microstructure. The equi-axed grains are among the coarse column grains, and some are the original grains of insufficiently melt or totally unmelt powder particles. The results tell the difference of the two kinds of voids, i.e., cavity and pore.

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Section: Microstructuresupporting

confidence: 87%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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3D characterization of the microstructure of LPBF- fabricated Inconel 718 alloy

Kang¹,

Huangb²,

Yub³

2023

MSEIJ

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“…The camera is equipped with a 6 MP lens with a focal length of 25 mm (1-24422, Navitar, Rochester, NY). Details about our off-axis monitoring system can be found in our previous works [20]. In this work, the print is monitored using the STWIP system and the off-axis camera, the data acquisition settings were 40,000 fps (128×96 px) and 4,000 fps (320×256 px) -corresponding to a eld of view of 200 mm ×180 mm on the build plate, respectively.…”

Section: Off-axis Camera Monitoring For Melt Pool Registrationmentioning

confidence: 99%

“…To retrieve the MP coordinates, the off-axis monitored MP images are rst corrected using perspective transformation through standard checkerboard calibration, followed by Otsu thresholding algorithm to cluster the pixels from the off-axis images into different groups based on pixel grayscale level. The Otsu thresholding method can effectively extract the melt pool core for coordinate calculation as detailed in our previous work [20]. The previous work uses down-sampling to accommodate the frame rate differences between the co-axial STWIP camera and the off-axis camera.…”

Section: Off-axis Camera Monitoring For Melt Pool Registrationmentioning

confidence: 99%

Melt pool width measurement in a multi-track, multi-layer laser powder bed fusion print using single-camera two-wavelength imaging pyrometry

Vallabh,

Zhang,

Anderson

et al. 2024

Int J Adv Manuf Technol

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In laser powder bed fusion (LPBF) additive manufacturing, melt pool characterization is one of the potential approaches toward rapid process quali cation and e cient non-destructive evaluation of printed parts. Especially melt pool width measurement is crucial for understanding the print process regimes, estimating the solidi ed melt pool depth, and identifying any process anomalies, among other attributes of interest. While existing works focus on monitoring melt pools of single scan tracks or single layer prints, melt pool characterization for a multi-track multi-layer (MTML) LPBF print has not been extensively studied. In this work, we employ our lab-designed coaxial single-camera two-wavelength imaging pyrometry (STWIP) system to monitor in situ melt pool properties during a MTML LPBF process. The STWIP-measured melt pool widths are validated using a serial sectioning machine (Robo-Met, UES). The in-situ STWIP and ex-situ Robo-Met measurement data are in close agreement with each other, having a mean absolute error and root mean squared error of 9.83 µm and 16.53 µm, respectively. Further we demonstrate the successful mapping of melt pool location and melt pool size on the printed MTML part. In sum, this work demonstrates the capability and the applicability of STWIP for accurate large-scale melt pool monitoring during LPBF processing of practical parts, thereby facilitating the development of LPBF process models and control strategies.

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