TWI provides expertise and support to industry in electron beam additive manufacturing, a high-speed metal 3D printing process. It uses an electron beam to melt metal wire or metal powder feedstock in a high vacuum to build parts layer-by-layer.
Our support includes involvement in specific projects as well as the creation (and updating) of process guidance notes for industry…
- Additive Manufacturing Certification Guidance Notes
We worked with Lloyd’s Register (LR) to produce – and then later update – guidance notes for the certification of products made using different additive manufacturing (AM) methods, including electron beam AM. Originally created in 2016, the guidance notes were created to help manufacturers establish the safety of additively manufactured parts. AM certification is important to industry as it ensures that businesses can verify the safety of products to protect operators, assets, the environment and the public. The provision of product assurance means that legal requirements have been met and that AM parts are suitable for their intended applications. The certification also demonstrates the capabilities and quality of the parts to customers and end-users.
As well as providing input into electron beam AM guidance, our experts have worked to improve procedures and processes themselves…
- Wire-Fed Electron Beam Additive Manufacturing
Wire-fed electron beam additive manufacturing allows for a large amount of material to be deposited quickly, but required machining to reach the final dimensional tolerances. The process has created interest in the aerospace industry as a means to reduce material wastage and scrap, but needed issues with distortion to be addressed in order to become an industrially viable solution. Our experts addressed this issue during a core research programme project in 2017, which led to the creation of a demonstrator aerospace wing rib to show the results of the work that calculated a 40% cost reduction when compared to machining from solid material.
- Titanium Aluminide Turbochargers
Our experts also provided input into the public-funded ‘TiAlCharger’ project to investigate the use of electron beam melting to fabricate a turbocharger wheel from successive layers of powder. This allowed for a hollow, lightweight, low-inertia rotor wheel to be formed, which was then joined to a steel shaft using the electron beam brazing process. The challenge was to create a joint between dissimilar materials that was robust enough to withstand vibrations, high temperatures and the rotational speeds present in a turbocharger unit. This fabrication method demonstrated the possibility to manufacture turbocharger wheels from TiAl, which (if of the required quality) retains its strength at high temperatures, expanding the usage of turbochargers to a broad range of engine types.
- Nano-Ti Project
TWI collaborated with Epoch Wires Ltd on the Nano-Ti project, investigating methods to control grain growth of additively manufactured components. The project investigated doped Ti6Al4V wire manufactured with small quantities of grain refiners, with the aim of making minor modifications to alloy composition and reduce columnar grain growth. The project determined the most efficient quantity and type of grain refinement addition and its resultant properties across a spectrum of different wire-based AM processes, including DED-LB, WAAM and DED-EB (Figure 1).