Varela Leniz Irene, Bakouche Taieb, Astigarraga Malen, Husson Florent, Zaldua Ane Miren, Gemini Laura, Vilas-Vilela José Luis, Etxeberria Leire
Leartiker S. Coop, Xemein Etorbidea 12A, 48270 Markina-Xemein, Spain.
ALPhANOV, Institut d'optique d'Aquitaine, Rue François Mitterrand, 33400 Talence, France.
Polymers (Basel). 2025 May 7;17(9):1289. doi: 10.3390/polym17091289.
Precision micromilling is currently widely used for the fabrication of injection mold inserts for the mass production of microfluidic devices. However, for complex devices with micrometer-scale and high density of structures, micromilling results in high production times and costs for production runs of hundreds or thousands of units. Femtosecond laser (fs-laser) technology has emerged as a promising solution for high-precision micromachining. This study analyzes the potential of fs-laser micromachining for the fabrication of injection mold inserts for the large-scale production of thermoplastic microfluidic devices. For the evaluation of technology, a reference design was defined. The parameters of the fs-laser process were optimized to achieve high resolution of the structures and optimal surface quality, aiming to minimize production times and costs while ensuring the quality of the final part. The microstructures were replicated in two different grades of COC (Cyclic Olefin Copolymer) by injection molding. The dimensional tolerance of the structures and the surface finish achieved both in the insert and the polymer parts were characterized by scanning electron microscopy (SEM) and confocal microscopy. The surface quality of the final parts and its suitability for microfluidic fabrication were also assessed performing chemical bonding tests. The fs-laser machining process has shown great potential for the mass production of microfluidic devices. The developed process has enabled for a reduction of up to 90% in the fabrication times of the insert compared to micromilling. The parts exhibited very smooth surfaces, with roughness values (Sa) of 64.6 nm for the metallic insert and 71.8 nm and 72.9 nm for the COC E-140 and 8007S-04 replicas, respectively. The dimensional tolerance and the surface quality need to be improved to be competitive with the finishes achieved with precision micromilling. Nonetheless, there is still room for improvement considering the significant reduction in the production times through new laser processing strategies.
精密微铣削目前广泛应用于制造用于大规模生产微流控器件的注塑模具镶件。然而，对于具有微米级尺寸和高密度结构的复杂器件，微铣削导致数百或数千个单位生产批次的生产时间长且成本高。飞秒激光（fs-激光）技术已成为高精度微加工的一种有前景的解决方案。本研究分析了fs-激光微加工在制造用于大规模生产热塑性微流控器件的注塑模具镶件方面的潜力。为了评估该技术，定义了一个参考设计。优化了fs-激光工艺参数以实现结构的高分辨率和最佳表面质量，旨在在确保最终零件质量的同时最小化生产时间和成本。通过注塑成型在两种不同等级的环烯烃共聚物（COC）中复制微观结构。通过扫描电子显微镜（SEM）和共聚焦显微镜对镶件和聚合物零件中结构的尺寸公差和表面光洁度进行了表征。还通过进行化学键合测试评估了最终零件的表面质量及其对微流控制造的适用性。fs-激光加工工艺在微流控器件的大规模生产中显示出巨大潜力。与微铣削相比，所开发的工艺使镶件的制造时间减少了多达90%。零件表面非常光滑，金属镶件的粗糙度值（Sa）为64.6 nm，COC E-140和8007S-04复制品的粗糙度值分别为71.8 nm和72.9 nm。尺寸公差和表面质量需要改进，以与精密微铣削获得的光洁度相竞争。尽管如此，考虑到通过新的激光加工策略生产时间大幅减少，仍有改进空间。
