Improvement strategy for the geometric accuracy of bead’s beginning and end parts in wire-arc additive manufacturing (WAAM)

Abstract

Cold metal transfer (CMT) based wire-arc additive manufacturing (WAAM) is a promising method for the production of large-scale and complex metallic parts because of its high efficiency, less heat input and low cost. However, a critical and common problem with the arc welding processes is the irregular geometry at the beginning and end parts of the bead due to the ignition and extinction of the arc. Based on experimental investigations of the irregularities and different possible optimization methods, an improvement strategy consisting of configurations with a varying travel speed and an extra return path is presented in this paper. Experimental results show that this strategy can effectively enhance the geometric accuracy at the beginning and end parts of different single beads. In the manufacturing of a thin-wall part and a multi-pass cladding, the improvement of geometric accuracy has also been achieved by this strategy.

Experimental investigation on deposits of ER70S-6 wire on SiO2 substrate using non-transferred arc-based wire arc additive manufacturing

“…Under the high value of current and voltage, the plasma jet temperature increases [25]. The interaction time between plasma jet and substrate reduces upon increase in TS that reduces the heat input [26, [33][34][35][36][37][38][39]42]. So the substrate temperature is not increasing so rapidly, which enhances the temperature gradient and promotes faster solidi cation [12].…”

Non-transferring arc and wire additive manufacturing: microstructure, mechanical properties and bulk texture evolution of deposits

“…The volume of metal deposited (DV) per unit length [equation (8)] has direct control over the bead width and height (Liu et al , 2019; Sarathchandra et al , 2020; Wang et al , 2022). The filler wire’s cross-sectional area (A) is fixed, so DV can only be regulated through WFS and TS.…”

“…Heat input is the prime controllable factor for penetration depth and dilution (Sarathchandra et al , 2020; Yin et al , 2020). WFS primarily decides the flow of arc current, which controls the heat input and wire melting rate (Mishra et al , 2023; Rodrigues et al , 2021; Wang et al , 2022). Under high WFS, current flow enhances the heat input and filler wire melting rate.…”

“…The switchback deposition strategy resulted in a 70% g-phase in the middle of deposition and enhanced the mechanical characteristics [yield strength (YS) ¼ 440 MPa, elongation ¼ 40%]. After deposition of one bead, Wang et al (2022) retracted the torch back from the arc exit point with a low TS (than original deposition) to fill the height deviation part. This approach maintained the height deviation within 7.1% for the entire component.…”

A hybrid approach consisting of multi-objective and multivariate analyses for WAAM specimens

“…CMT-WAAM is recognized as a smooth and emerging technology [9]. Because of its high efficiency, low heat input , and low cost, this is a potential method for the production of huge and intricate parts with feasible deposition rates [10,11].…”