Additive manufacturing: how to create the new materials

The test aimed at replacing traditional metal moulds with polymer-based elements such as Carbon PA and Carbon PEEK, chopped carbon fibre filled nylon 6 and PEEK, respectively, to reduce costs and time with the advantage of increasing the design flexibility.

“Techno-polymers such as Polyether Ether ketone (PEEK), combined with a high presence of chopped carbon fibres, open up some interesting horizons for development,” said Stefano Corvaglia, intellectual property manager and head of R&D of the aerostructures division. “Testing with these materials is of particular scientific and technological interest since they give some structural and chemical-physical properties of extreme technological significance to the items produced, for example thermal and chemical resistance”.

He added: “What’s more, thanks to a technology that enables us to achieve previously unattainable levels of precision in fabrication, we can improve our capacity and speed in developing prototypes.”

The Roboze solution used in the test is the ARGO 500, an industrial 3D printer designed to help companies in the digital transformation of their production processes. Roboze has EMEA HQ in Italy and US HQ in Texas. In particular, Roboze 3D printers are equipped with a patented beltless movement, the Beltless System, capable of guaranteeing precision levels up to 0.01 mm and process repeatability, with the highest performing polymers and composite materials in the entire sector.

By optimising the printing parameters of the Roboze ARGO 500 in the test phase, Leonardo managed to remove any surface porosity and roughness, typical of the additive manufacturing with fused filament. This step was also essential for maintaining the vacuum during the curing process.

An important aspect of using technopolymers’ additive technology is the chance to use them for high temperature applications. The high level of thermal stability, given by the polymer and carbon fiber, does not cause significant deformations in the moulds. Their durability with the repetition of thermal cycles is now being studied.

“Thermoplastic techno-polymers are polymers made up of non-interconnected chains that are linear or have few branches; by raising the temperature we’re able to bring them to a viscous state and therefore to shape them and, in the case of additive technology, to fabricate them in layers” concluded Corvaglia.

The production flexibility of Roboze solutions and the opportunity to produce with technopolymers capable of withstanding the pressures and temperatures of the vulcanization cycles of the composites (cross-linking process of the polymer chains in the composite matrix - CFRP) represents a turning point for the aerospace industry, offering reduced development costs and times compared to traditional techniques.

The project, led by Nicola Gallo, R&D lead engineer at Leonardo's aerostructures division, and in collaboration with Roboze, already got a first recognition during the A&T 2020 fair in Turin last February, receiving the Innovation 4.0 Award in the research and university category.

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