Strategies for metallic powder reuse in powder bed fusion: A review

Metal additive manufacturing is a rapidly growing field because it enables extensive freedom in design coupled with the production of new materials that would be impossible to synthesise by conventional manufacturing. Successful powder bed fusion processes require careful monitoring of the powder since changes there can influence part properties and performance. This raises the issue of powder reuse, which is crucial for improving the financial viability and lowering the environmental impact of the process. As powder is widely known to degrade during reuse, powder reuse strategies must therefore be carefully devised. Here, we review three of the most common powder reuse methods: the single batch and collective ageing methods, the top up method, and the refreshing method. The effects that these reuse methods have on common powder and part properties, as well as an evaluation of powder traceability and powder handling procedures are discussed and evaluated. It is our purpose to set out the merits and challenges of the various powder reuse methods to frame a basis for their selection in academic research and industrial applications.