Development of a New Cold Metal Transfer Arc Additive Die Manufacturing Process

Abstract

Due to its high efficiency, cold metal transfer (CMT) arc additive manufacturing presents considerable potential in the aluminium alloy additive manufacturing industry. However, during CMT arc additive manufacturing, the surrounding air environment promotes the lateral flow of liquid aluminium and the instability of the molten pool, reduces the surface quality and material utilisation of deposition walls, and causes internal hydrogen pores and coarse columnar grains, which negatively affect the structure and mechanical properties of the deposition walls. This study developed a CMT arc additive die manufacturing process to control the substrate material and deposition path to improve the physical properties of the deposition wall. The experimental results indicated that the copper plates can affect molten pool flow and material formation in the additive process, minimise hydrogen pores, and refine columnar grains. The porosity dropped from 2.03% to 0.93%, and the average grain size decreased from 16.2 ± 1.4 to 13.6 ± 1.3 μm, thereby enhancing the structure and mechanical properties of the deposition wall to attain standard additive manufacturing products.

Improvement of Cooling Effect and Dimensional Accuracy of Wire and Arc Additive Manufactured Magnesium Alloy by Active-Cooling-Based Contacting Copper Blocks

“…Therefore, we focused on the active cooling method shown in Figure 1d, which improves the dimensional accuracy and heat dissipation of WAAM by contacting the solid structures with the molten metal [27,28]. Direct contact of a solid bearing a high thermal conductivity with molten Mg alloy is expected to provide a strong cooling effect and dimensional accuracy to fabricated Mg alloy objects while avoiding combustion.…”

“…Fang L et al [27] improved the cooling effect and dimensional accuracy of WAAM-wall structures using an Al alloy and employing the developed heat transportation structure based on the thermoelectric cooling technique. Zhang A et al [28] used pure copper plates with high thermal conductivity as a heat transportation object and observed that the copper plates could minimize hydrogen pores and improve the ultimate tensile strength of the WAAM wall structure of Al alloys. However, these previous studies investigated the cooling effect only on Al alloys, not Mg alloys.…”