Chinese Journal of Lasers, Volume. 51, Issue 10, 1002308(2024)
In‑Situ Monitoring and Diagnostics for Deposition Defects in Laser Powder Bed Fusion Process Based on Optical Signals of Melt Pool (Invited)
Figures & Tables(15)
Fig. 1. Deposition defects caused by powder spreading during printing. (a) Before printing; (b) during printing; (c) after printing
Fig. 3. Morphology and particle size of AlSi10Mg alloy powder. (a) SEM morphology of powder; (b) particle size distribution
Fig. 4. Schematics of experimental model. (a) Pre-processed substrate by milling; (b) single-layer printing after powder spreading process
Fig. 5. Spatial distributions of optical signals for melt pool of Group B samples. (a) Melt pool light intensity; (b) melt pool area
Fig. 6. Statistical results of melt pool light intensity under different process parameters. (a) Mean values under different laser powers; (b) mean values under different scanning speeds; (c) coefficients of variation under different laser powers; (d) coefficients of variation under different scanning speeds
Fig. 7. Statistical results of melt pool area under different process parameters. (a) Mean values under different laser powers; (b) mean values under different scanning speeds; (c) coefficients of variation under different laser powers; (d) coefficients of variation under different scanning speeds
Fig. 8. Surface roughness measurement results and three-dimensional morphologies under different powder thickness conditions. Three-dimensional morphologies of Group B samples when powder thickness is (a) 30, (b) 90, (c) 150, (d) 210, and (e) 270 μm;(f) relationship between surface roughness and powder thickness under different laser process parameters
Fig. 9. SEM images of surface morphologies and enlarged images. (a) Relationship between surface deposition defects and powder thickness under different laser process parameters; (b)‒(e) enlarged images of areas in dotted boxes
Fig. 10. Relationship between melt pool size and internal pore defect under different powder thicknesses. (a) Cross-sectional morphologies of samples after polishing and corrosion; (b)‒(f) locally magnified images
Fig. 11. Relationship between melt pool intensity and melt pool area. (a) Good quality; (b) remediable quality; (c) high risk with deposition defects
Fig. 12. ROC curve analysis under different thresholds. (a) 0.18 V; (b) 0.21 V; (c) 0.25 V; (d) 0.29 V
Fig. 13. Distributions of abnormal monitoring signals of test samples when small threshold is 0.21 V. (a) Samples under different laser powers and powder thicknesses; (b) samples under different scanning speeds and powder thicknesses
Table 1. Experimental process parameters
View tableTable 1. Experimental process parameters
Data set Laser power
P /W
Scanning speed v /
（mm·s-1）
Hatch space
h /μm
A 240 1000 90 B 200 1000 90 C 160 1000 90 D 200 800 90 E 200 1200 90
Table 2. Proportions of abnormal signals in test samples
View tableTable 2. Proportions of abnormal signals in test samples
Powder
thickness /μm
Proportion of abnormal signals /% Laser power
of 240 W
and scanning speed
of 1000 m/s
Laser power
of 200 W
and scanning speed
of 1000 m/s
Laser power
of 160 W
and scanning speed
of 1000 m/s
Scanning speed
of 800 mm·s-1
and laser power
of 200 W
Scanning speed
of 1200 mm·s-1
and laser power
of 200 W
30 0 0.24 17.90 0.08 0 60 0.27 1.23 54.15 1.01 0.04 90 1.10 4.48 42.95 6.21 0.04 120 3.96 8.90 55.40 12.74 2.17 150 13.49 21.49 66.32 23.47 11.44 180 20.70 35.79 74.60 28.22 22.19 210 29.05 57.78 78.04 35.09 63.85 240 33.73 72.51 77.27 48.86 75.02 270 40.05 80.52 77.01 57.92 77.45 300 40.50 58.69 77.73 59.20 53.47
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Xiangyuan Chen, Huiliang Wei, Tingting Liu, Kai Zhang, Jiansen Li, Zhiyong Zou, Wenhe Liao. In‑Situ Monitoring and Diagnostics for Deposition Defects in Laser Powder Bed Fusion Process Based on Optical Signals of Melt Pool (Invited)[J]. Chinese Journal of Lasers, 2024, 51(10): 1002308
Paper Information
Category: Laser Additive Manufacturing
Received: Jan. 8, 2024
Accepted: Mar. 5, 2024
Published Online: Apr. 27, 2024
The Author Email: Wei Huiliang (hlwei@njust.edu.cn)
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