Experts: Adriaan Spierings (Inspire)
In additive manufacturing, also known as 3D printing, a three-dimensional component is assembled from individual thin layers during the manufacturing process. For this purpose, the raw material, which consists of plastic, metal or ceramic, either in liquid form as a photopolymer, or else as a powder, fibre or film, is solidified layer by layer. The solidification occurs with the aid of a laser, an electron beam or an electric arc, or alternatively by bonding fibres or powdery particles.
Picture: Jon Tyson, Unsplash
One advantage of the procedure is that it takes a complex three-dimensional structure that is difficult to manufacture and reduces it to a two-dimensional problem that is easier to manufacture. This reduction of complexity enables the production of geometrically complex components for many industrial application areas. However, the mechanical properties of parts manufactured in this way are not identical to those of conventionally produced parts, such as those made using a casting procedure. Alongside microstructural differences, additively manufactured parts exhibit a certain residual porosity, meaning reduced material integrity. Such material weaknesses are significant in the context of mechanical properties, making it necessary to adapt quality control and to insert subsequent finishing into the process, thus making additive manufacturing more cost-intensive.
It is therefore crucial that new comprehensive quality management methods be developed for additive manufacturing processes. Ideally, these should be able to detect material defects and microstructural differences in the material while it is still in the production process – meaning on the spot. This would make the processes more robust and enable them to run with less variation in final quality. Suitable technologies must be developed to monitor the various additive manufacturing processes and the involved material systems. The monitoring technologies must be integrated into the plant control system, so as to be able to correctively intervene in the process flow during the assembly process. Not only could this make the manufactured components’ material integrity more reproducible and improve the parts’ quality, but these methods would also help to enable quantitative assessment of the processes’ robustness. This is an essential step towards a comprehensive quality management system that encompasses certification of additive manufacturing equipment and the components produced with it, as well as the required personnel.
