Strategies for wire arc additive manufacturing of thin walls and overhangs

In recent decades, additive manufacturing has become a widely discussed topic. Wire arc additive manufacturing (WAAM) is an example of additive manufacturing based on direct energy deposition. The core principle of this technology is depositing filler material layer by layer using electric arc welding. Most additive technologies face manufacturing limits in the form of overhangs and residual stresses, and WAAM is no exception. This paper deals with wire arc additive manufacturing and focuses on production strategies for thin walls and overhangs. The article describes the influence of production strategies on residual stresses and production accuracy. Five different strategies for thin wall production were proposed and verified, and overhangs were produced. Results show that the position of the beginnings and ends of the weld bead is crucial for production accuracy and residual stresses. Suitable strategies to produce overhangs fabricated with low angular deviation and sufficient surface quality were identified.