In situ 3D monitoring and control of geometric signatures in wire and arc additive manufacturing

Lack of monitoring and quality control of in situ forming process is a major bottleneck in Wire and Arc Additive Manufacturing (WAAM). Among various process control, the control of the geometric signatures is of high importance. This paper presents a method of in situ monitoring and closed-loop control of topography measurement. A laser-based areal topography measurement sensor is used to measure the surface geometric signatures of the formed layer. A topography control strategy is carried out by processing and analyzing the 3D surface profile data. To increase the computing speed and efficiency, a depth-image method is proposed to process the 3D surface point clouds data and extract the 3D contour signatures of the shaped layer. Experiments were designed to verify the feasibility and stability of the system and the experimental results indicate that the proposed method can adaptively deal with the surface topography quality and handle the concave and convex parts of the shaped layer.