The nominations for the2021 3D Printing Industry Awards现在开放。您认为谁应该在今年的演出中列出入围名单？现在有发言权。
来自弗莱堡大学and the斯图加特大学have developed a novel method of 4D printing wearable medical devices that self-adjust to the anatomy of the patient.
受空气马铃薯植物（Dioscorea bulbifera）的传播机制的启发，可以预先编程，以在暴露于水分时进行复杂的运动。该团队已经利用了4D打印一种自触角矫形器夹板的方法，该钉子自行缠绕在患者的手臂上。
该研究的合着者蒂法尼·郑（Tiffany Cheng）告诉Materials Today, “We showed how functional and structural principles from biology could be transferred to technical material systems. Our work constitutes an important step in expanding the design space and tunable functionality of bio-inspired solutions.”
生物启发的4D打印
当3D打印结构的形状随着时间的推移而变形时，它被称为4D打印。这些几何变化可以以多种方式诱导，其中一些最常见的是电刺激，热和水分。许多4D打印的对象都使用智能放置的层和折叠进行了预编程，以收缩并扩展以产生所需的效果。
顺便说一句，我们可以通过从大自然中汲取灵感来学到有关4D印刷系统的知识 - 毕竟，Evolution是那里最好的设计师之一。
In this case, the Freiburg team turned to the air potato, a vine plant capable of climbing trees by winding itself around the trunk of the host. Air potatoes sprout outgrowths called stipules, which help tension the winding stem and exhibit a squeezing force on the host plant. This allows the air potato to work its way up its host, bringing it closer to that much-needed sunlight.
A 4D printed, self-tightening wrist splint
In a bid to emulate the movement mechanism of the air potato, the researchers employed a computational design strategy that involved selectively printing ‘bend lines’ into the geometry of the splint itself. Like creases in a piece of paper, these bend lines are designed to determine how, where, and to what degree the splint will bend when exposed to moisture.
在这里，物质选择也至关重要，因为只有对水分的反应，夹板的致动才有可能。为此，团队必须使用木聚合物复合材料，该复合材料轻松吸收并释放了水分。
印刷结构还包括几个与弯曲线结合使用的肿胀和稳定层，以达到类似螺旋的螺旋状形式。此外，团队在夹板表面上打印了口袋，这些口袋将螺旋向外推到设备中产生张力，最终导致整个夹板的收缩。这使该设备能够在佩戴者的手臂上拧紧，以获得个性化的，舒适的贴合性，从而为手腕提供了支撑。
The study concludes, “Through proving this concept with a working prototype of a common orthotic device, we envision that this design process might enable medical experts to physically design, prototype, and custom-fit self-adjusting orthotic devices without any specialized knowledge in digital modeling.”
Further details of the study can be found in the paper titled ‘生物启发的运动机制：自调整的4D打印可穿戴系统的计算设计和材料编程’. It is co-authored by Tiffany Cheng, Marc Thielen et al.
The applications of 4D printing go far beyond the medical sector, with soft robotics and electronics also on the cards. A team of researchers fromLinköpingUniversity，瑞典，以前有4D printed a set of microactuators用于使用基于自定义挤出的3D打印机的软微型机器人。虽然4D打印的软机器人通常仅限于中心级或毫米级，但该团队能够将印刷设备缩放到微米域，从而达到约20微米的区域的厚度。
最近，德国电子3D打印公司Neotech Amtannounced a new欧盟支持的Penta项目Ampere，它试图开发可靠且可扩展的混合添加剂制造工艺来生产多功能的4D机电系统。该项目将着重于加速4D制造，以加快用于照明，信号和电力电子等的智能系统的可靠生产。
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Featured image shows the 4D printed wrist splint. Image via University of Freiburg.
