An experimentally-validated modeling framework for dot-by-dot WAAM process and product set-up: Application to rods

Wire Arc Additive Manufacturing (WAAM) enables high deposition rates and large build volumes compared to other Additive Manufacturing (AM) technologies. Further advancements have been achieved through the dot-by-dot (DbD) WAAM strategy, which allows the fabrication of complex geometries, particularly intricate lattice structures, with enhanced control over material properties via thermal cycle regulation. However, DbD WAAM presents significant challenges in geometric accuracy, primarily due to its thermal cycle, where heat buildup and limited interpass temperature control lead to unsatisfactory geometries and defects, requiring manual interventions that compromise repeatability and reliability.This work introduces the initial findings of the CIRCULAR WELD research project, focused on developing a comprehensive experimentally-validated modeling framework for DbD WAAM. Designed to set-up both process and product without the need for expensive and unreliable trial-and-error, the framework integrates Geometrical (PG), Thermal (TM), Microstructural-Mechanical (MM), and Mechanical-Structural (MS) digital models. These models investigate mutual interactions to link process parameters with geometrical accuracy, microstructural features, mechanical parameters, and structural performance. This paper presents preliminary results of the framework’s application to single DbD WAAM rods of different nominal diameters (from 4 to 6 mm), focusing on initial model calibration and validation. Experimental results confirmed the efficiency of calibrated geometrical and thermal models, enabling good process repeatability and rods with controlled geometrical features (reduced surface roughness and lack of straightness) and mechanical properties (coefficients of variation <10% for most of them). Overall, the rods demonstrated mechanical and structural performances compliant with steel grade S275, suitable for structural applications.