Fig. 1. PBF-L forming and monitoring equipment

Fig. 2. Sample position relative to air outlet

Fig. 3. Online monitoring system for PBF-L molten pool

Fig. 4. Radiation intensity of molten pool versus number of layers

Fig. 5. Relationship between output voltage and temperature

Fig. 6. Radiation intensity waveform of molten pool

Fig. 7. Relative position relationship between soot and melting point. (a) Upwind; (b) downwind

Fig. 8. Radiation intensity of molten pool versus number of layers for different positions

Fig. 9. Process of dust taken out of forming bin by scanning at different positions. (a) Near air outlet, in early scanning stage; (b) near air outlet, in middle scanning stage; (c) near air outlet, in final scanning stage; (d) far away from air outlet, in early scanning stage; (e) far away from air outlet, in middle scanning stage; (f) far away from air outlet, in final scanning stage

Fig. 10. Distributions of scan line angles on different layers

Fig. 11. Mean intensity versus scan line angle in single period. (a) In second period; (b) in third period

Fig. 12. Comparison of scan lines at different scan angles. (a) Diagram of scan lines at different angles; (b) sample solid drawing