08-NOV-21
打印ed polymers that change shape once in a predefined way when heated? This is now possible thanks to a 4D printing technology developed in the Fraunhofer Cluster of Excellence Programmable Materials CPM. The extent of the change in shape of the printed objects is drastic: they can shrink by up to 63 percent. In the future, 4D manufacturing technologies could be used to produce parts that exhibit a specific behavior only after they take their predefined shape, for example as fasteners in the assembly of components in the medical technology, mechanical engineering, automotive and aviation industries.
3 d打印技术是流行,作为添加剂manufacturing technology, it offers numerous advantages. For example, products and prototypes can be individually designed and are quickly available. A team of researchers at Fraunhofer CPM is significantly expanding the benefits by producing printed objects using so-called 4D printing. This technology adds the dimension of time, or 1D, to the dimension of space, or 3D. In this way, objects can be printed from shape memory polymers that can change their shape once at a later point in time when exposed to heat - and in quite a remarkable way: rod-shaped samples measuring around four centimeters in length shrink by up to 63 percent. Specific curvatures are also possible in a targeted manner. “We initially started with a relatively simple rod geometry, but ultimately we were able to produce more complex hollow cylinders and hollow cuboid-shaped samples,” says Dr. Thorsten Pretsch from the Fraunhofer Institute for Applied Polymer Research IAP, who is coordinating the project at Fraunhofer CPM. “For all the geometries we investigated, we specified the desired material behavior in advance.”
Shrinkage behavior and curvatures can be precisely adjusted
通常有两种方法可以调整对温度升高的响应。首先是材料的选择 - 这里的研究人员开发了具有形状记忆特性的新型热塑性聚氨酯或TPU。该团队还表明，获得4D打印的发现也可以转移到另一种热塑性聚合物中：它们从基于生物的聚合物聚合物聚合物或PLA产生了可收缩的印刷物体。第二种可能性在于印刷过程的巧妙管理。“关键是，我们给打印过程中的材料很少，很少有时间冷却。结果，内部应力急剧存储在材料中。然后，随后的收缩效应非常明显。” Pretsch说。简而言之，材料，加工温度和打印速度的选择不仅可以调整收缩行为，还可以调整弯曲状态。
从单体到机械回收的开发
该项目的第一步是开发材料并将发现从TPU转移到PLA。第二步是开发一个演示者 - 一个揭开台的开门机，该开门机缩小到门把手上，以便可以用肘部操作而无需手接触。拆卸很简单：通过重新加热；门开瓶器从手柄上脱离，而不会留下任何残留物。当不再需要打印对象时，可以将其接地并重新处理成灯丝，至少可以再使用一次4D打印。»这个概念是整体的，并以未来为导向。就摇篮到摇篮的方法而言，我们已经完成了整个产品周期 - 从单体和聚合物合成的选择到演示者的4D打印及其机械回收，«Pretsch总结了。
The four Fraunhofer institutes contributed their specific expertise: the Fraunhofer IAP synthesized the shape memory polymer, further developed the 4D printing technology and carried out the mechanical recycling. Linda Weisheit from the Fraunhofer Institute for Machine Tools and Forming Technology IWU developed the concept of programmable stiffness of the 4D materials. The Fraunhofer Institute for Industrial Mathematics ITWM conducted mathematical simulations to design the demonstrator. “For example, we investigated how the force is distributed in the door opener when it is loaded. We were also interested in finding out which design is better in terms of material consumption,” explains Dr. Heiko Andrä. The practical tests took place at the Fraunhofer Institute for Mechanics of Materials IWM. “Here, for example, the question was which torques occur when the door opener is loaded,” explains Dr. Tobias Amann.
资料来源：Fraunhofer学院
以前的pressrease
下一个pressRelease
{{comment.datetimestampdisplay}}}
{{comment.comments}}