High-Resolution DLP 3D Printing for Complex Curved and Thin-Walled Structures at Practical Scale: Archimedes Microscrew

Abstract

As three-dimensional (3D) printing becomes increasingly prevalent in microfluidic system fabrication, the demand for high precision has become critical. Among various 3D printing technologies, light-curing-based methods offer superior resolution and are particularly well suited for fabricating microfluidic channels and associated micron-scale components. Two-photon polymerization (TPP), one such method, can achieve ultra-high resolution at the submicron level. However, its severely limited printable volume and high operational costs significantly constrain its practicality for real-world applications. In contrast, digital light processing (DLP) 3D printing provides a more balanced alternative, offering operational convenience, lower cost, and print dimensions that are more compatible with practical microfluidic needs. Despite these advantages, most commercial DLP systems still struggle to fabricate intricate, high-resolution structures-particularly curve, thin-walled, or hollow ones-due to over-curing and interlayer adhesion issues. In this study, we developed a DLP-based projection micro-stereolithography (PμSL) system with a simple optical reconfiguration and fine-tuned its parameters to overcome limitations in printing precise and intricate structures. For demonstration, we selected an Archimedes microscrew as the target structure, as it serves as a key component in microfluidic micromixers. Based on our previous study, the most effective design was selected and fabricated in accordance with practical microfluidic dimensions. The PμSL system developed in this study, along with optimized parameters, provides a reference for applying DLP 3D printing in high-precision microfabrication and advancing microfluidic component development.

Keywords: Archimedes microscrew; DLP 3D printing; microfluidic component; photo-polymerization; projection micro-stereolithography (PμSL).

Figure 1

Schematic diagram of the PμSL 3D printing system setup.

Figure 2

Test print designs for testing (a) wall thickness t (=10 μm to 50 μm) and (b) wall height h (=100 μm to 500 μm).

Figure 3

Generation of the Archimedes microscrew model for printing: (a) rectangular generator undergoing simultaneous rotation and translation; (b) resulting screw surface after one full turn; (c) rectangular cuboid section extracted for use; (d) final microscrew with rectangular cross-sectional throughput.

Figure 4

Example of some of the slices of the solid model at three different depths.

Figure 5

Printed results of the design shown in Figure 2a with designed wall thicknesses of (a) 10 μm and (b) 20 μm.

Figure 6

Comparison of the designed and printed wall thicknesses.

Figure 7

Print results of the design in Figure 2b with a designed wall thickness of 10 μm and a height of (a) 100 μm, (b) 200 μm, (c) 300 μm, (d) 400 μm, and (e) 500 μm.

Figure 8

SEM images of the printed Archimedean micromixer structures: (a) 500 μm width and (b) 800 μm width.