Closing The Loop - Towards defect free additive manufacture

制造业对革命并不陌生，从世纪末的第一次工业革命，即手工生产的机械化，一直到世纪的计算机化，制造和生产技术不断发展。最新的工业革命，工业4.0，我们发现自己身处其中，是由机器变得“智能”驱动的。“机器和系统现在已经增加了传感器和人工智能，可以自己做出决定。3D打印或增材制造（AM）是这场革命的关键部分，因为它可以生产以前不可能的组件，以及更高效的设计，灵活的生产和更少的浪费。与从大块材料开始并移除材料直到产生所需形状的减材制造相反，AM通过以高度自动化的方式逐层构建（添加）对象来工作。然而，与许多传统制造工艺相比，增材制造仍不成熟，在被视为“智能”之前还需要进一步的进步。这些缺陷可能包括裂纹、内部孔隙或杂质，并且这些缺陷会显著影响所制造部件的性能。这些缺陷的后果可能是组件过早失效，甚至更糟，意外失效。金属的制造工艺，如焊接、锻造和铸造，比增材制造成熟得多，已经被广泛研究了几个世纪。因此，人们更好地理解了为什么会出现这些缺陷，以及如何优化这些过程以最大限度地减少这些缺陷。目前，增材制造正处于获取知识的同一旅程中，我们相信通过采用“智能”方法可以加速这一旅程。这项工作将创新的过程监控设备集成到增材制造机器中，以检测在构建过程中形成的缺陷，使我们能够在原位修复这些缺陷，并增强我们对这些缺陷发生原因的理解。这将有助于实现和加速金属增材制造零件在结构最终用途和高精度应用中的使用。这种方法将使我们对新制造的增材制造组件的质量和安全充满信心，减少对缓慢和昂贵的后处理过程的需求，并加速增材制造作为一种制造技术的采用。

The manufacturing industry is no stranger to revolutions, from the first industrial revolution in the late 18th century which saw the mechanisation of hand production, all the way to computerisation in the 20th century, manufacturing and production technology continues to evolve. The latest industrial revolution, Industry 4.0, which we find ourselves amidst, is driven by machines becoming "smart." Machines and systems are now augmented with sensors and artificial intelligence to make their own decisions. 3D printing or additive manufacturing (AM) is a key part in this revolution as it enables production of components not previously possible as well as more efficient designs, flexible production and less waste. As opposed to subtractive manufacturing which starts from a large block of material and removes material until it produces the desired shape, AM works by building (additively) an object layer-by-layer in a highly automated way. However, AM is still immature compared to many traditional manufacturing processes and requires further advancements before it can be considered "smart".When producing parts in metals, defects can occur. These defects may consist of cracks, internal pores or impurities, and these defects can significantly impact the performance of a manufactured component. The consequence of these defects can be premature, or even worse, unexpected, failure of the component. Manufacturing processes for metals such as welding, forging and casting are far more mature than AM, having been studied extensively for centuries. Consequently, there is a far better understanding of why these defects occur and how to optimise these processes to minimise them. Currently, AM is on the same journey of knowledge acquisition; a journey we believe can be accelerated by embracing a "smart" approach.This work will integrate innovative process monitoring equipment into AM machines to detect defects as they form during the build process, allowing us to fix them in-situ as well as enhancing our understanding of why they occur. This will help enable and accelerate the use of metal AM parts for structural end-use and high precision applications. This approach will give us confidence in the quality and safety of newly built AM components, reducing the need for slow and costly post-processing processes, and accelerate the adoption of AM as a manufacturing technology.