University of Bordeaux students develop novel WAAM process
Two students from France’s University of Bordeaux, report that they have developed an innovative Wire Arc Additive Manufacturing (WAAM) process. The students, Rémi Thuillet-Méric and Théo Baldacchino, explain that by depositing only where needed, with as little as 2 mm of wire feedstock, substantial material savings can be achieved using this wire-based form of Directed Energy Deposition (DED). The team reportedly designed and built their metal AM machine from scratch, using recycled material and hardware from previous student projects.
The technology is said to have one key advantage that allows it to stand out in its sector – the work area theoretically allows the Additive Manufacturing of parts with infinite length. Even if the width and height of the parts are constrained by the dimensions of the machine, the length is not constrained.
The students remarked that the use of WAAM is growing in the naval, aeronautics and space industries. However, there are key challenges to be solved in order to increase the performance, specifically parts with curved shapes. These are difficult to manufacture with regular parallel layers without support because of an excessive overhang in certain regions. This new technology can solve the issue, states the students.
By leveraging the digital nature of AM, processing steps are reduced and finished products can be obtained much more quickly. The preparation and slicing time for Additive Manufacturing is equivalent to that of the most common cartesian axis machines, which allows it to be simple and quick to use, reducing the costs of preparing for AM. The particular kinematics allows it to produce hollow parts, with slopes, and uneven surfaces, all of which helps to reduce material costs, as required by industry, and also reduce environmental impact.
Tests were conducted to implement a path planning strategy, applicable to a large number of geometric shapes, to guarantee good quality of the final additively manufactured part. Since the arc start and stop phases generate noticeable defects in the final part, the optimisation criteria for tool path planning was the minimisation of arc start/stop phases. Additionally, gravity plays a key role and has to be considered for complex shape buildup. Several shapes were additively manufactured which included a hollow cube, W-profile and M-profile.
The initial idea for the project was generated during an internship with Dr Robin Kromer, Associate Professor in the Institute of Mechanical Engineering (I2M) at the University of Bordeaux. The students added that the overall objective is to present a ready-to-go Additive Manufacturing machine, with the in-situ monitoring and functional surface machining integration. They are aiming to minimise material waste and simplify manufacturing operations, opening this technology up to large-scale production of finished products.
