Optimized design and additive manufacture of double-sided metal mirror with self-supporting lattice structure

Lattice structure has excellent mechanical properties to develop lightweight devices, and additive manufacture makes it possible to construct complex lattice without extra cost. Especially, with the development of structural optimization technology, design of gradient lattice structure with optimized material distribution has become a research hotspot. In this paper, a double-sided metal mirror infilled with topology optimization (TO) based self-supporting lattice structure and fabricated with selective laser melting (SLM) was proposed. Considering the manufacturing constraints of SLM technology, commonly used body-centered cubic (BCC) lattice was modified and coordinate transformed to construct the self-supporting infill of the mirror. To further improve the mechanical properties of the structure, density-based TO method was introduced to optimize the diameters of all struts in the infill lattice. Finally, an SLM 3D printer was utilized to manufacture the mirror, and both stiffness and anti-vibration performance of the original and two different lattice infilled metal mirrors were evaluated through FEA. Compression tests were also conducted to verify the compressive property of all mirrors. Even though with 20% less material cost, both computational and experimental verifications have shown that the optimized lattice infilled mirror has much better mechanical properties compared with the original design.