Cure depth control for complex 3D microstructure fabrication in dynamic mask projection microstereolithography
Cure depth control for complex 3D microstructure fabrication in dynamic mask projection microstereolithography
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DOI：
10.1108/13552540910925072
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发表时间：
2009-01-01
影响因子：
3.9
通讯作者：
Lee, Seok-Hee
中科院分区：
文献类型：
--
作者：
Choi, Jae-Won;Wicker, Ryan B.;Lee, Seok-Hee
目的-本文的目的是探索一种利用光吸收的方法，用于改进使用先前开发的动态掩模投影微立体光刻（MSL）系统的复杂三维（31）微部件的制造。立体光刻系统的常见问题并且在MSL中特别重要的是在制造面向下的表面时紫外光源不受控制地穿透到可光致交联的树脂中。为了精确制造具有朝下表面的复杂3D部件，将化学光吸收剂Tinuvin 327（TM）以不同浓度混合到丙烯酸酯基光固化树脂中，设计/方法/途径-基于Tinuvin 327的高吸收特性，选择其作为光吸收体（类似于0.4）在365 nm（MSL系统中使用的过滤光波长）。在树脂中使用四种浓度的Tinuvin 327（0.00%、0.05%、0.10%和0.15%（w/w）），并进行固化深度实验。为了研究不同浓度的Tinuvin 327对复杂的3D微结构制造的影响，几个微结构与悬垂功能，如风扇和弹簧fabricated.Findings -结果表明，较高浓度的Tinuvin 327减少渗透深度，从而固化深度。对于含有0.15%（w/w）Tinuvin 327的树脂，与不含光吸收剂的200 μ m的固化深度相比，实现了类似于30 μ m的固化深度。四种树脂溶液用于制造复杂的3D微结构，并且根据微部件的几何形状，在给定的辐照度和曝光能量下需要不同浓度的Tinuvin 327以成功制造（0.05%和0.1%（w/w）的浓度为风扇和弹簧提供了最精确的构造，研究限制/影响-虽然需要两种不同浓度的光吸收剂在溶液中，以证明两种不同的微零件几何形状的成功制造（风扇和弹簧），使用单一辐照度和曝光能量进行实验。一个单一的解决方案与光吸收剂可能已被用来制造这些微零件通过改变辐照度和/或曝光能量，虽然改变这些参数的影响，几何精度，机械强度，整体制造时间，和其他变量没有explored.Originality/值-这项工作系统地研究了3D微结构制造使用不同浓度的光吸收剂的解决方案，并且证明了不同的面向下的微特征需要不同的光吸收特性。
Purpose - The paper's aim is to explore a method using light absorption for improving manufacturing of complex, three-dimensional (31)) micro-parts with a previously developed dynamic mask projection microstereolithography (MSL) system. A common issue with stereolithography systems and especially important in MSL is uncontrolled penetration of the ultraviolet light source into the photocrosslinkable resin when fabricating down-facing surfaces. To accurately fabricate complex 3D parts with down-facing surfaces, a chemical light absorber, Tinuvin 327 (TM) was mixed in different concentrations into an acrylate-based photocurable resin, and the solutions were tested for cure depths and successful micro-part fabrication.Design/methodology/approach - Tinuvin 327 was selected as the light absorber based on its high absorption characteristics (similar to 0.4) at 365 nm (the filtered light wavelength used in the MSL system). Four concentrations of Tinuvin 327 in resin were used (0.00, 0.05, 0.10, and 0.15 percent (w/w)), and cure depth experiments were performed. To investigate the effects of different concentrations of Tinuvin 327 on complex 3D microstructure fabrication, several microstructures with overhanging features such as a fan and spring were fabricated.Findings - Results showed that higher concentrations of Tinuvin 327 reduced penetration depths and thus cure depths. For the resin with 0.15 percent (w/w) of the Tinuvin 327, a cure depth of similar to 30 mu m was achieved as compared to similar to 200 mu m without the light absorber. The four resin solutions were used to fabricate complex 3D microstructures, and different concentrations of Tinuvin 327 at a given irradiance and exposure energy were required for successful fabrication depending on the geometry of the micro-part (concentrations of 0.05 and 0.1 percent (w/w) provided the most accurate builds for the fan and spring, respectively).Research limitations/implications - Although two different concentrations of light absorber in solution were required to demonstrate successful fabrication for two different micro-part geometries (a fan and spring), the experiments were performed using a single irradiance and exposure energy. A single solution with the light absorber could have possibly been used to fabricate these micro-parts by varying irradiance and/or exposure energy, although the effects of varying these parameters on geometric accuracy, mechanical strength, overall manufacturing time, and other variables were not explored.Originality/value - This work systematically investigated 3D microstructure fabrication using different concentrations of a light absorber in solution, and demonstrated that different light absorption characteristics were required for different down-facing micro-features.