3D Printing multifunctionality: structures with electronics
3D Printing multifunctionality: structures with electronics
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DOI：
10.1007/s00170-014-5717-7
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发表时间：
2014-05-01
影响因子：
3.4
通讯作者：
Wicker, Ryan B.
中科院分区：
文献类型：
--
作者：
Espalin, David;Muse, Danny W.;Wicker, Ryan B.
当NASA探索3D打印在下一代太空探索飞行器开发中的力量时，CubeSat Trailblazer于2013年11月发射，将3D打印结构与嵌入式电子产品集成在一起。太空提供了展示3D打印设备的耐用性所必需的恶劣环境，包括辐射、极端热循环和低压-所有这些都在原子到宏观尺度上攻击结构。因此，在轨道上运行的设备可以依赖于许多地面环境，包括许多国防和生物医学应用。3D打印的CubeSat模块（一个子系统，约占10 x 10 x 10 cm CubeSat外壳提供的总体积的10%）具有一个基板，该基板专门适合利用3D打印的可用体积，以提供体积效率。基于当时3D打印电子产品的最佳制造技术，立体光刻（SL），一种缸光聚合技术，用于制造介电结构，而导电油墨被分配在通道中以提供组件之间的电气互连。尽管结构通过了包括温度循环、冲击和振动以及排气测试在内的资格认证，但SL中使用的光固化材料无法提供长期功能所需的耐久性水平。此外，众所周知，SL基板材料所需的具有低温固化能力的导电油墨在导电性方面提供次优性能。为了应对未来3D打印电子产品中的这些挑战，下一代机器正在开发中，被称为多（3D）系统，这意味着使用多种技术来生产3D，多材料，多功能设备。基于用热塑性塑料取代光固化聚合物所需的挤出工艺，已经开发了基于熔融沉积成型（FDM）技术的材料挤出系统，其集成了其他技术以补偿FDM在表面光洁度、最小尺寸特征尺寸和孔隙率方面的不足。此外，为了最大限度地减少导电油墨的使用，一种新颖的热嵌入技术在FDM工艺中断期间将铜线浸入热塑性电介质结构中，从而提供高性能、坚固的互连和接地层，并意外地改善了结构的机械性能。本文通过实验结果将用于3D打印电子产品的立体光刻与基于FDM的系统进行了比较和对比，并展示了一种基于FDM的自动化工艺，用于生产单独使用FDM无法实现的功能。除了使用直接写入电子电路的可能性外，这种新型制造还使用了热塑性塑料和铜线，这在3D打印电子产品的性能和耐用性方面提供了实质性的改善。
While NASA explores the power of 3D printing in the development of the next generation space exploration vehicle, a CubeSat Trailblazer was launched in November 2013 that integrated 3D-printed structures with embedded electronics. Space provides a harsh environment necessary to demonstrate the durability of 3D-printed devices with radiation, extreme thermal cycling, and low pressure-all assaulting the structure at the atomic to macroscales. Consequently, devices that are operational in orbit can be relied upon in many terrestrial environments-including many defense and biomedical applications. The 3D-printed CubeSat module (a subsystem occupying approximately 10 % of the total volume offered by the 10 x 10 x 10-cm CubeSat enclosure) has a substrate that fits specifically into the available volume-exploiting 3D printing to provide volumetric efficiency. Based on the best fabrication technology at the time for 3D-printed electronics, stereolithography (SL), a vat photopolymerization technology, was used to fabricate the dielectric structure, while conductive inks were dispensed in channels to provide the electrical interconnect between components. In spite of the structure passing qualification-including temperature cycling, shock and vibration, and outgas testing-the photocurable materials used in SL do not provide the level of durability required for long-term functionality. Moreover, the conductive inks with low-temperature curing capabilities as required by the SL substrate material are widely known to provide suboptimal performance in terms of conductivity. To address these challenges in future 3D-printed electronics, a next generation machine is under development and being referred to as the multi(3D) system, which denotes the use of multiple technologies to produce 3D, multi-material, multifunctional devices. Based on an extrusion process necessary to replace photocurable polymers with thermoplastics, a material extrusion system based on fused deposition modeling (FDM) technology has been developed that integrates other technologies to compensate for FDM's deficiencies in surface finish, minimum dimensional feature size, and porosity. Additionally, to minimize the use of conductive inks, a novel thermal embedding technology submerges copper wires into the thermoplastic dielectric structures during FDM process interruptions-providing high performance, robust interconnect, and ground planes-and serendipitously improving the mechanical properties of the structure. This paper compares and contrasts stereolithography used for 3D-printed electronics with the FDM-based system through experimental results and demonstrates an automated FDM-based process for producing features not achievable with FDM alone. In addition to the possibility of using direct write for electronic circuitry, the novel fabrication uses thermoplastics and copper wires that offer a substantial improvement in terms of performance and durability of 3D-printed electronics.