Additive manufacturing of millimeter-scale micron-accuracy 3D structures

In this work, we demonstrate a developed 3D printing based on two-photon polymerization for achieving millimeter-scale, micron-accuracy 3D structures (MM-3DS), which combines the femtosecond laser of 800 nm and low magnification objective lens of 10×. The commercial photoresist SU-8 is used in 3D printing system for improving mechanical strength and chemical stability of MM-3DS. The 3D microstructures are preprogrammed and optimized by considering the scanning mode and experiment parameters. During 3D printing process, micron features are written within the interior of SU-8 film via localized polymerization driven by nonlinear two-photon absorption process. By the 3D movement in ~1 mm scale of the focused beam, a customized MM-3DS can be produced. We have fabricated a customized MM-3DS with a size of 1.6 mm and an accuracy of 10 μm. The influence of volume for the printing structures V_s on the printing time T exhibits a linear behavior, indicating that the printing speed is 0.248 mm³/h under the current conditions. This technology offers a flexible and low-cost method of generating highly customizable, precisely controlled MM-3DS, which is promising for the manufacture of complex functional structures and devices for the microfluidics, microelectronics, photonics and so on.