The position-dependent feature in current vat photopolymerization-based additive manufacturing leads to challenges in controlling the dimensional accuracy of printed components. To overcome this intrinsic limitation, we propose a time-dependent dynamic laser writing (DLW) approach for the precise volumetric printing of complex-shaped lenses. In the DLW-based volumetric printing, the formed surface is generated by accumulating the material growth functions (MGFs) on the scanning path, where the MGF is created by the laser direct irradiation with controlled energy doses. Benefiting from the stability of MGFs and the process homogenization, the DLW is less sensitive to process errors when compared to current vat photopolymerization-based additive manufacturing techniques. Furthermore, the continuous scanning leads to the naturally ultra-smooth feature of the printed surfaces. As a demonstration, a millimeter-scale spherical lens was printed in 5.67 min, achieving a three-dimensional (3D) form error of 0.135 μm (root mean square, RMS) and a surface roughness of 0.31 nm (RMS). The printing demonstrated comparable efficiency while achieving form errors an order of magnitude smaller than those of state-of-the-art continuous layer-wise and volumetric printing methods. In addition, polymer lens arrays, freeform polymer lenses, and fused silica lenses were successfully printed, demonstrating promise for advancing the state-of-the-art in 3D printing of precision lenses.

The lightness and high strength-to-weight ratio of the magnesium alloy have attracted more interest in various applications. However, micro/nanostructure generation on their surfaces remains a challenge due to the flammability and ignition. Motivated by this, this study proposed a machining process, named the ultraprecision diamond surface texturing process, to machine the micro/nanostructures on magnesium alloy surfaces. Experimental results showed the various microstructures and sawtooth-shaped nanostructures were successfully generated on the AZ31B magnesium alloy surfaces, demonstrating the effectiveness of this proposed machining process. Furthermore, sawtooth-shaped nanostructures had the function of inducing the optical effect and generating different colors on workpiece surfaces. The colorful letter and colorful flower image were clearly viewed on magnesium alloy surfaces. The corresponding cutting force, chip morphology, and tool wear were systematically investigated to understand the machining mechanism of micro/nanostructures on magnesium alloy surfaces. The proposed machining process can further improve the performances of the magnesium alloy and extend its functions to other fields, such as optics.