SEE MORE MAKE MORE: Secondary Electron Energy Measurement Optimisation for Reliable Manufacturing of Key Materials

加法制造(AM)，或3D打印，是一种令人兴奋的新工业生产形式，有望给医疗保健、能源、航空航天和交通运输等各种行业带来革命性的变化。通过允许由各种材料形成更坚固、更轻和更复杂的部件，AM将在满足未来几十年的新兴技术需求方面发挥关键作用。在AM已经产生巨大兴奋的一个领域是骨组织工程，为患有退行性疾病或需要在事故或癌症后进行面部重建的患者生产植入物。然而，可重复地制造大型承重植入物仍然是一个重大挑战。从理论上讲，AM允许复制极其复杂的几何形状，同时也考虑到骨组织的结构、机械和细胞属性的变化。这种灵活性对于生产承载3D打印骨骼至关重要，这种骨骼具有取代金属植入物的强度，但也模拟复杂的血管网络。AM的大部分灵活性来自于它使用的复合材料，它结合了几种不同材料的理想特性。越来越多地，在一种使用激光不断熔化(烧结)复合材料的AM形式中，聚合物与纳米碳混合，使材料更坚固和更导电。然而，该领域的一个突出挑战是确保碳均匀分布在整个基质聚合物中，以生产具有可靠性能的印刷部件。我们还需要能够在AM期间实时监控纳米碳的分布，这将需要先进计量的新的创新方法。利用我们团队独特的设施和经验，我们将应对这些工程挑战，为AM社区提供生产定制高质量组件的能力的阶段性变化。为了做到这一点，我们将在我们最近在开发高光谱成像新方法方面取得的重大突破的基础上再接再厉，即允许我们绘制材料的化学和结构属性以及这些属性在不同条件下如何变化的技术。使用电子作为探针提供了有关纳米碳颗粒如何相互作用及其环境的信息，例如，当用激光加热时。这些信息对优化AM工艺至关重要，但由于这项技术是在纳米级运行的，因此在印刷时对整个组件进行监控是不现实的。为此，我们将使用另一种基于热发射的高光谱成像方法，类似于我们可以从火灾中热煤发出的熟悉辉光中测量温度的方法。通过结合这些电子成像和热发射检测方法，我们将能够控制纳米碳如何分布在复合材料中，以及这如何影响关键的宏观性能，如孔隙率、导电性、强度和表面光洁度。总之，这种新的高光谱成像框架将使研究人员和行业在各种应用中使用AM，从而在成本、产量、能源效率和寿命方面获得收益。一旦我们的框架建立，我们将通过将其应用于骨组织支架的AM来展示其有效性，该支架来自我们将开发的包含纳米碳和生物相容性聚合物的新型复合材料。通过优化激光加热工艺和控制纳米碳的分布和状态，我们将与我们的行业合作伙伴Lucideon一起通过测试验证，制造出适合临床使用的支架。其他合作伙伴包括NPL、ASTEC、YPS、SpINTEX和FBK，他们将通过在锂离子电池、制药、能源材料和加速器技术方面的应用来增强我们项目的影响力。

Additive manufacturing (AM), or 3D printing, is an exciting new form of industrial production that promises to revolutionise sectors as diverse as healthcare, energy, aerospace, and transport. By allowing stronger, lighter, and more complex components to be formed from a variety of materials, AM will play a critical role in meeting emerging technological needs over the coming decades. One area in which AM is already generating huge excitement is in bone tissue engineering for the production of implants for patients who have degenerative diseases or who need, for example, facial reconstruction following an accident or cancer. However, making large and load-bearing implants reproducibly is still a significant challenge. AM theoretically allows the reproduction of extremely complex geometries while also accounting for variation in the structural, mechanical, and cellular properties of bone tissue. Such flexibility will be essential to produce load-bearing 3D printed bones that have the strength to replace metal-based implants but which also mimic intricate vascular networks.Much of the flexibility of AM arises from its use of composites which combine the desirable properties of several different materials. Increasingly, in a form of AM that uses a laser to continually melt (sinter) the composite material, polymers are mixed with nano-carbon to make materials stronger and more conductive. However, an outstanding challenge in the field is to ensure that the carbon is evenly distributed throughout the matrix polymer to produce printed components with reliable properties. We also need to be able to monitor nanocarbon distribution in real time during AM which will require new, innovative methods of advanced metrology.Using the unique facilities and experience of our team, we will address these engineering challenges to provide the AM community with a step-change in their ability to produce bespoke high-quality components. To do this, we will build on significant breakthroughs we have recently made in developing new methods of hyperspectral imaging, that is, techniques that allow us to map the chemical and structural properties of a material and how these change under different conditions. Using electrons as a probe provides information on how nanocarbon particles interact with each other and their environment, for example, when heated with a laser. Such information is critical to optimise AM processes but, because this technique operates at the nanometer level, it is not practical for monitoring whole components whilst they are printed. For this, we will use another method of hyperspectral imaging based on thermal emission, similar to how we can measure temperature from the familiar glow emitted by hot coal in a fire. By combining these methods of electron imaging and thermal emission detection, we will be able to control how nanocarbon is distributed throughout a composite material and how this affects critical macroscale properties such as porosity, conductivity, strength, and surface finish. Together, this new hyperspectral imaging framework will benefit researchers and industry using AM for various applications leading to gains in cost, yield, energy efficiency, and lifetime.Once our framework is established, we will demonstrate its effectiveness by applying it to AM of bone tissue scaffolds from a novel composite we will develop containing nanocarbon mixed with a biocompatible polymer. By optimizing the laser heating process and controlling nanocarbon distribution and state, we will make scaffolds that are fit for clinical use, as validated through tests with our industry partner Lucideon. Other partners include NPL, ASTeC, YPS, Spintex, and FBK who will enhance the impact of our project through applications in Li ion batteries, pharmaceuticals, energy materials, and accelerator technologies.