Selective Laser Melting And Optics Focus Performance Of Lobster-eye Bio-inspired Structure

The Lobster-eye Bio-inspired Structure(LBS)is a microchannel array structure with small size thin wall,multiple intersections and inclined angle,which has been widely applied in the fields of highenergy ray detection,high-energy ray backscatter collection and light wave band focus.But it is difficult to form LBS using traditional machining technologies.In this paper,selective laser melting(SLM)technology was used to form LBS,the process control of SLM forming of thin-walled structure,intersecting thin-walled structure and integral components were systematically studied,and the optical focus performance of the SLM integral component was preliminarily measured in this paper.The influence of laser power and scanning speed on the densification behavior of SLM thinwalled structure was studied.It was found that high laser energy input can reduce the porosity due to the elimination of partial melting and gas residue,thus obtaining a thin-walled structure with high relative density(99.98%).However,the excessive laser energy input destroyed the continuity of molten tracks,which led to the formation of balls on the surface of the thin-walled structure,thus reducing the surface quality of the thin-walled structure.The effects of different areas of thin-walled intersecting structure on microstructure and properties were studied.It was found that the cooling rate of the thin-walled intersecting area was higher than that of the thin-walled area,which resulted in the higher porosity in the thin-walled intersecting area than that of the thin-walled area.The size of molten pool and the sub-grain in the thin-walled intersecting area(85.208 ?m,240 nm ± 16 nm)were smaller than those in the thin-walled area(59.375?m,270 nm ± 19 nm),resulting in the higher average nano hardness(2.277 GPa ± 0.044 GPa)in the thin-walled intersecting area.The influence of laser power and scanning speed on the densification behavior of LBS integral component fabricated by SLM was studied.It was found that the highest relative density(99.7%)of SLM-processed LBS can be obtained with laser power of 400 W and scanning speed of 2200 mm/s.The inner surface roughness in the middle position(17.419 ?m)of SLM-processed LBS was higher than that in both bottom and top area(14.159 ?m,14.064 ?m),caused by the combined effects of microchannel with inclined angle and heat transfer ability of the melting pool in different positions along the building direction.The optical focusing performance of SLM-processed LBS was tested,and it was found that the SLM-processed LBS with a microchannel width of 1 mm exhibited the best light focus ability.