Study on the deposition accuracy of omni-directional GTAW-based additive manufacturing

In gas tungsten arc welding (GTAW) based additive manufacturing (AM), omni-directional deposition with side feeding is common when depositing complex parts, which is different from the gas metal arc welding (GMAW). While side feeding may lead to unstable deposition process and deposition deviation. In this paper, a wire melting simulation model was established to analyse the behaviour of the wire in the arc column. An index of weld bead offset tolerance capacity is proposed to quantitatively analyse the sensitivity of the weld bead offset to the wire feed speed. Single-layer experiments were conducted to analyse the relationships between the deposition parameters and the weld melting/bead offset. A multi-layer sample with an actual usable area ratio of 95.11 % was deposited by using the proposed model and the optimized deposition parameters. The experimental results show that the control of the weld melting offset is the key factor in realizing the stability and accuracy of omni-directional GTAW-based AM.