INFLUENCE OF SHIELDING GASES ON THE WAAM PROCESS FOR ALUMINIUM IN REDUCING DEFECTS AND INCREASING PROCESS EFFICIENCY

Abstract

WAAM (Wire Arc Additive Manufacturing) technology is a manufacturing technique based on combining metallic wire with arc welding techniques to melt it and generate, layer by layer, the geometry of the final part. This additive manufacturing (AM) process is offering a new manufacturing perspective to the industry, as it allows higher deposition rates than other additive manufacturing techniques despite having lower dimensional accuracy in its raw state. Compared to other AM technologies, WAAM uses simple equipment and achieves higher deposition rates.

This study analysed the influence of shielding gases on defect reduction and process efficiency improvement. To this end, thin-walled test pieces were made using pure argon, Perfect 1 (argon + O2 + N2O) and H30 (70% argon + 30% helium). Computed tomography and macrographs were used to analyse defects. In addition, measurements of the temperature of each layer of material added were taken using a thermal imaging camera.

The results obtained show a decrease in the level of defects and porosity through the use of specific gas mixtures, also reducing the intensity and voltage of welding, which translates into lower thermal input, helping to prevent the molten bath from spreading before solidification, so that the ratio between width and height tends to be lower.