权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

3D printing of micro-scale graded shape memory components for in-vivo actuated medical devices

用于体内驱动医疗设备的微型分级形状记忆组件的 3D 打印

基本信息

批准号：
EP/T005076/1
负责人：
Duncan Hand
金额：
$ 32.24万
依托单位：
Heriot-Watt University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2019
资助国家：
英国
起止时间：
2019 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FT005076%2F1
关键词：
3D printing micro scale graded

项目摘要

Micro-robots have great potential for evaluation and treatment of medical conditions. Such devices require highly controlled actuation at a micro-scale to provide controlled motion, testing of tissue compliance, biopsy, etc, and this is a prospect offered by functionally-graded shape memory alloys (SMAs). An SMA has the ability to "remember" its original shape and that when deformed returns to its pre-deformed shape when heated. Such alloys have sparked great interest ever since their first development. Functional grading of SMAs (i.e. locally modifying the properties of the material to tailor the SMA effect in different parts of the device) allow the design of more complex and hence much more controllable actuation mechanisms. Devices and components manufactured from functionally graded SMAs can provide actuation in response to external stimulation (stress or temperature variation, e.g. via induction heating), outperforming conventional actuation mechanisms such as electromagnets or electrical motors in terms of work output density. Such performance is ideal for micro-devices for minimally invasive medical applications such as precise incision, tissue identification, tactile sensing for disease and tweezing, as well as more ambitious shape transformations for "unpacking" structures in situ and "intelligent" stents and patches.The manufacturing challenge here is to achieve that functional grading at a micro-scale, by a combination of locally tailoring the material composition and thermal history. This will be achieved via development of a novel process, functionally graded Laser Induced Forward Transfer (FG-LIFT). This process will use a multi-track 'donor ribbon' (rather like a multicoloured typewriter ribbon) to deposit "sub-voxels" (of typical dimensions a few microns across and hundreds of nm high) of different metals, e.g. Ti, Ni and Cu onto a target substrate, in order to construct voxels each consisting of a number of subvoxel layers of different metals. By altering the laser parameters, subsequent thermal treatment will be used to provide control of interdiffusion within and between voxels providing very tight localised control of composition. 3D microstructures will hence be constructed by continuing to add additional voxels. This FG-LIFT process will be used to manufacture sub-mm and mm-scale SMA components with functional grading at a scale of 10's of microns. This highly challenging concept requires 3D control - at the micro-scale - of both material composition and thermal treatment. By depositing the functionally graded SMA material onto substrates with appropriate material properties (e.g. carbon fibre mats or trace heaters), additional tailoring of the overall performance of the device will be achieved.

微型机器人在医疗状况的评估和治疗方面具有巨大的潜力。这样的装置需要在微尺度下高度受控的致动以提供受控的运动、组织顺应性的测试、活组织检查等，并且这是由功能梯度形状记忆合金（SMA）提供的前景。SMA具有“记忆”其原始形状的能力，并且当变形时，SMA在加热时恢复到其变形前的形状。这种合金自从第一次开发以来就引起了人们的极大兴趣。SMA的功能分级（即局部修改材料的特性以调整设备不同部分的SMA效应）允许设计更复杂且因此更可控的致动机构。由功能梯度SMA制造的器件和组件可以响应于外部刺激（应力或温度变化，例如通过感应加热）提供致动，在工作输出密度方面优于传统的致动机构，例如电磁体或电动机。这种性能非常适合用于微创医疗应用的微型设备，例如精确切割、组织识别、疾病触觉传感和镊子，以及用于原位“拆包”结构和“智能”支架和贴片的更雄心勃勃的形状转换。这里的制造挑战是在微观尺度上实现功能分级，通过局部定制材料成分和热历史的组合。这将通过开发一种新的工艺，即功能梯度激光诱导前向转移（FG-LIFT）来实现。该过程将使用多轨道“供体带”（相当类似于多色打字机带）来将不同金属（例如Ti、Ni和Cu）的“子体素”（典型尺寸为几微米宽和几百nm高）存款到目标衬底上，以便构造体素，每个体素由不同金属的多个子体素层组成。通过改变激光参数，随后的热处理将用于提供对体素内和体素之间的相互扩散的控制，从而提供对组成的非常紧密的局部控制。因此，3D微结构将通过继续添加额外的体素来构建。该FG-LIFT工艺将用于制造亚毫米和毫米级SMA组件，其功能分级为10微米。这一极具挑战性的概念需要在微观尺度上对材料成分和热处理进行3D控制。通过将功能梯度SMA材料沉积到具有适当材料特性的基底（例如碳纤维垫或迹线加热器）上，将实现装置整体性能的额外定制。