Today the partners announced that the first WAAMpeller is close to completion; in fact, the 3D printing has been completed on the propeller prototype. The WAAMpeller was fabricated at RAMLAB, aka the Rotterdam Additive Manufacturing Lab, located in the Port of Rotterdam. It was 3D printed from a nickel aluminum bronze alloy using Wire Arc Additive Manufacturing (WAAM, hence the name) with a Valk welding system and Autodesk software. Designed by Promarin, the propeller has a triple-blade structure that matches the propellers used on Damen’s Stan Tug 1606.
A great deal of work has gone into 3D printing the WAAMpeller, with the participants in the project learning a lot about material properties as they went along.
“This is because 3D printed materials are built up layer by layer,” said Kees Custers, Project Engineer in Damen’s R&D department. “As a consequence, they display different physical properties in different directions – a characteristic known as anisotropy. Steel or casted materials, on the other hand, are isotropic – they have the same properties in all directions.”
Therefore, extensive material testing was required to ensure compliance with Bureau Veritas standards.
“This involved printing two straightforward walls of material – then using a milling machine to produce samples for lab testing of tensile and static strengths,” explained Custers. “The challenge has been to translate a 3D CAD file on a computer into a physical product. This is made more complex because this propeller is a double-curved, geometric shape with some tricky overhanging sections.”
They managed it, however, and the completion of the prototype WAAMpeller lays a foundation for the creation of even more complex and more reliable 3D printed propeller designs in the future, according to Yannick Eberhard of Promarin’s R&D department.
“Material characterization and mechanical testing have been an important part of this project. We have to make sure that the material properties meet the needs of the application. Material toughness, for example – ensuring that the propeller is able to absorb significant impact without damage. But we have also been working towards optimising the production strategy for 3D metal deposition. This includes bead shape and width, as well as how fast we can deposit the printed material,” said Wei Ya, Postdoctoral Researcher from the University of Twente at RAMLAB.
“For large scale 3D metal deposition, the WAAMpeller is really ground-breaking for the maritime industry. This technology is a fundamental change in the concept of how we make things. With additive manufacturing, you can print most metallic components that are needed in principle. There is so much potential for the future – these techniques will have a big impact on the supply chain.”
The WAAMpeller is 1,350 mm in diameter and weighs 400 kg. It’s an excellent showcase for the capabilities of RAMLAB’s 3D printer, which can print objects with maximum dimensions of 7 x 2 x 2 meters. Now that 3D printing is complete, the WAAMpeller will be CNC milled at Autodesk’s Advanced Manufacturing Facility in Birmingham, UK. This first propeller will be used for display services, and next month the team will begin production on a second WAAMpeller, which will eventually be installed onto one of Damen Shipyards Group’s tug boats.
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[Images provided by Damen Shipyards Group]