77540Closing The Loop - Towards defect free additive manufactureClosedCollaborative R&DInnovate UKThe 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.