Analytical model for distortion prediction in wire plus arc additive manufacturing

An analytical model was developed to predict bending distortion of the base-plate caused by residual stresses in additively manufactured metal deposits. This avoids timeconsuming numerical simulations for a fast estimation of the expected distortion. Distortion is the product of the geometry factor K, which is determined by the cross-section of substrate and deposit, and the material and process factor S, which is the quotient of residual stress and the Young’s Modulus. A critical wall height can be calculated for which the structure distorts the most. This critical height is typically less than 2.5 times the thickness of the substrate. Higher walls increase the stiffness of the cross-section and reduce the distortion with increasing height.