Automated toolpath planning with 3D implementation of a parabolic weld bead deposition model for wire arc additive manufacturing repair

Abstract

To ensure sufficient repair of a metal structure damaged from, e.g., corrosion or wear by wire arc additive manufacturing (WAAM), appropriate toolpath planning and prediction of material deposition for the welding process are required. In the current work, a planner employing combined contour and raster pattern paths based on a sliced surface scan of the damage was developed. To extend existing empirical models for material deposition during welding to the two-dimensional paths used in WAAM, a paraboloid deposition function was used. Realistic deposition rates for uneven substrates were ensured by continuously adjusting the vertex height of the paraboloid in closely timed deposition events along the path. The deposition prediction can be used to assess if additional layers of repair welding are needed to fill a damage. For a repair with a build height of around 13 mm, the damage was sufficiently filled after following the generated toolpath plan, and a minimal amount of voids were observed. Errors in the material deposition prediction were within ±1 mm in most of the repair. Errors in the predicted deposition were higher in the start/stop regions of weld beads, presumably because the ignition procedure in the welding machine was not accounted for.