Influences Of Process Parameters On Twin Tungsten Electrode – Wire Electrode Indirect Arc Additive Manufacturing Process

In this paper, the effects of wire-tungsten ( d_1 ) and tungsten-tungsten ( d_2 ) spacing on the forming characteristic of twin tungsten electrode - wire electrode indirect arc (TTWIA) additive manufacturing were comprehensively studied. The arc shape, droplet transfer, and molten pool behavior were recorded respectively. Results showed that as d_1 or d_2 increased, the arc shape of TTWIA diverged and the coupling intensity was weakened. Besides, the liquid stream became thick as well as the larger droplet diameter and lower transfer frequency, mainly attributed to the reduced arc current density and detachment forces acting on the droplet. Additionally, on account of the decreased arc pressure and droplet impingement force on the molten pool, the transverse flow tendency of liquid metal was diminished, and the molten pool width of TTWIA decreased, which was adverse to the spreading of the deposited layer. Moreover, the forming quality of the thin-walled part deteriorated, together with the increased surface roughness and reduced material utilization rate, which mainly attributed to the instability of the molten pool because of the lowered normal reaction acting on the molten pool of the present deposited layer.