Experimental Technology and Management

随着3D打印技术的快速发展，3D打印本科教学日益受到重视。该文设计了一项基于数字光处理（DLP）技术的3D打印教学实验，指导学生自主设计并搭建DLP 3D打印设备，学习设备的控制及参数调节。通过树脂固化实验，引导学生建立光敏树脂的光照时间与固化厚度关系，深入了解光固化原理，并基于灰度打印，培养学生的科研素养和独立思考能力。该实验不仅让学生体验了3D打印的完整流程，还有助于培养他们的跨学科思维、数据分析能力和创新意识，为未来的学术研究和工程实践奠定基础。

[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.