数字光处理 3D 打印设备的搭建与教学应用实验设计

[Objective] As 3D printing emerges as a transformative force in manufacturing and biomedical fields, China emphasizes its integration into undergraduate education to nurture interdisciplinary innovators. However, existing curricula often lack system-level, hands-on training bridging hardware design, process optimization, and advanced printing techniques. This study addresses this gap by developing a comprehensive teaching experiment centered on Digital Light Processing (DLP) 3D printing. The dual objectives are to (1) enable students to independently construct and operate a DLP printer, enhancing their understanding of photopolymerization and system integration, and (2) investigate how grayscale printing modulates material properties and precision, fostering analytical and research skills. [Methods] Students assemble a DLP printer using a DLP4710 projector (405 nm wavelength, 2W optical output) with a 1 920×1 080 Digital Micromirror Device (DMD) chip. A Raspberry Pi 4B serves as the control core, coordinating projection timing and platform movement via UART communication protocols. A Nema23 stepper motor, coupled with a 5 mm lead screw, enables precise vertical layer control (10 μm resolution). Critical steps involve optical alignment to ensure uniform illumination across the 136×76.5 mm build area and mechanically stabilizing the resin vat to minimize layer misalignment. Using ANYCUBIC ABS-LIKE photopolymer resin, students systematically correlate exposure time (1–30 s) with cured layer thickness. Students project a 10×10 mm square pattern and measure layer thickness using a vernier caliper. Concurrently, they quantify light intensity across grayscale levels (0–255) with an LP100 power meter to establish grayscale-light relationships. Dog-bone tensile specimens are designed in SolidWorks, sliced into layers using CHITUBOX, and printed with grayscale gradients (0–255). Post-printing, students evaluate dimensional accuracy using digital microscopy and assess mechanical performance via tensile testing to quantify strength-precision trade-offs. [Results] The experimental outcomes demonstrate both technical and pedagogical successes: 1) Students independently constructed a functional DLP printer, achieving a lateral resolution of 70 μm. Light intensity measurements confirmed a nonlinear relationship between grayscale values and light output, saturating beyond grayscale 200; 2) Cured thickness followed a logarithmic growth trend with exposure time. Notably, a 2-second exposure produced a 200 μm cured layer, highlighting the resin’s rapid photopolymerization kinetics. However, prolonged exposure induced over-curing, leading to dimensional instability; 3) Higher grayscale values enhanced light intensity, promoting denser polymer networks and increasing tensile strength. However, this mechanical improvement coincided with reduced lateral precision. Significantly, minimal precision loss occurred at 30% grayscale, underscoring the necessity of balancing light intensity and exposure parameters for optimal performance. [Conclusions] This experiment establishes a replicable pedagogical model for 3D printing education, immersing students in the full process of device development, material characterization, and advanced manufacturing. By engaging in hands-on printer assembly, resin curing analysis, and grayscale optimization, learners gain practical insights into the synergies between optical engineering, material science, and digital control systems. The observed trade-offs between mechanical strength and geometric fidelity emphasize the importance of parameter optimization in real-world applications—a skill rarely addressed in traditional coursework. Future iterations could explore multi-material printing (e.g., elastomer-rigid polymer composites) or biocompatible resins for medical applications, further aligning academic training with industrial and biomedical challenges. Ultimately, this framework equips students with the interdisciplinary agility, technical proficiency, and critical thinking required to pioneer innovations in additive manufacturing.