Fig. 1. Schematic diagram of sample. (a) Schematic diagram of sample; (b) molded sample

Fig. 2. Field emission scanning electron microscope SUPRA55

Fig. 3. 316L stainless steel powder

Fig. 4. SLM 125HL printer

Fig. 5. Three-dimensional profiler

Fig. 6. Topography of upper surface (v＝0.8 m/s). (a) Sample No. 14 (P＝275 W); (b) sample No. 19 (P＝325 W);(c) sample No. 24 (P＝350 W)

Fig. 7. Topography of vertical surface (P＝275 W). (a) Sample No. 11 (v＝0.5 m/s); (b) sample No. 13(v＝0.7 m/s)

Fig. 8. Topography of up-skin surface (P＝275 W, v＝0.7 m/s). (a) Magnification is 63; (b) magnification is 153

Fig. 9. Topography of down-skin surface (P＝275 W, v＝0.7 m/s) . (a) Magnification is 29; (b) magnification is 490

Fig. 10. Mesoscopic morphology of upper surface (P＝275 W). (a) Sample No. 11 (v＝0.5 m/s); (b) sample No. 13 (v＝0.7 m/s)

Fig. 11. Mesoscopic morphology of up-skin surface (P＝275 W). (a) Sample No. 12 (v＝0.6 m/s); (b) sample No. 15 (v＝0.9 m/s)

Fig. 12. Mesoscopic morphology of Vertical surface (P＝275 W). (a) Sample No. 12 (v＝0.6 m/s); (b) sample No. 15 (v＝0.9 m/s)

Fig. 13. Relationship between process parameters and melting width. (a) Relationship between scanning speed and melting width; (b) relationship between laser power and melting width

Fig. 14. Schematic diagram of lap joint section

Fig. 15. Schematic diagram of effective melt channel overlap

Fig. 16. Schematic diagram of related factors such as roughness of vertical surface and melting width. (a) Relationship between side roughness and melting width; (b) principle of side sticking powder

Fig. 17. Relationship between melting width and roughness

Fig. 18. Influence of different process parameters on the roughness of upper surface. (a) Different scanning speeds (P＝275 W); (b) different laser powers (v＝0.6 m/s)

Fig. 19. Influence of different process parameters on surface roughness of up-skin surface. (a) Different scanning speeds (P＝275 W); (b) different laser powers (v＝0.6 m/s)

Fig. 20. Influence of different process parameters on roughness of vertical surface. (a) Different scanning speeds (P＝275 W); (b) different laser powers (v＝0.6 m/s)