An appealing example of 3D printing on an industrial scale – also known as additive manufacturing – made headlines in 2017, when a 400 kilo metal ship’s propeller prototype was successfully printed in Rotterdam. UT researcher Tom Vaneker is currently working on a follow-up project involving yet more enormous metal shipping parts. ‘The possibility of producing very large objects in a single piece at lightning speed on location offers great opportunities for the manufacturing industry. Take the ship’s propeller, for example: a ship at sea having problems with its propeller will soon be able to send the specifications back to shore and when it returns to harbour a freshly printed propeller will be ready and waiting. The production speed of the technology we used in this project is 10 to 100 times higher than that of other methods. What’s more, maintenance-friendliness and durability of printed objects are ground-breaking, partly because they can only consist of one component.'
The ship’s propeller was printed in the context of a research project that Vaneker is involved in on behalf of the UT: Aim2XL (Additive Manufacturing for Extra Large Metal Components). The project focuses on printing large metal shipping parts that range from 1 to 10 meters in size. Although production for a tug boat propeller is in full swing, the technique used (‘direct metal deposition’) requires a lot of research for further development. One focal point in this research is the field of material properties. Vaneker: ‘Within one printed product, differences occur in the material’s physical properties. These deviations can result in serious quality or safety risks, among other things. We do not yet know enough about the possible effects, or about how to prevent them. Even the accuracy is not yet at its best: getting this kind of propeller ready for actual use involves a lot of manual finishing after the printing process, such as milling work. But these are obstacle we hope to overcome, so that in the long run 3D printing technology can take its place among other production technologies.’
The same development curve is underway in a project for Aeronamic companies at the Fraunhofer Project Center. Named 3D2SKY and launched at the end of 2017, this project focuses on achieving higher quality and accuracy in printing complex components for the aeronautics industry. Vaneker: ‘The metal printing technique we are using for 3D2SKY, powder bed fusion technology, is still relatively expensive and slow. But there is a lot of potential here, too. Just think: printing aircraft engine parts that now consist of twenty different components, all in one go. Even if production remains more expensive, this can save a lot of money on things like maintenance and assembly. And potentially, the lifespan of these products will be a lot longer. We are not yet able to guarantee these benefits, but we are working hard to develop these techniques into certifiable production methods, so that the industry can take full advantage of the many benefits.’
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