VARIAÇÃO DA FREQUÊNCIA DE PULSO NA MANUFATURA ADITIVA DE ALUMÍNIO COM GTAW ALIMENTADO / VARIATION OF PULSE FREQUENCY IN ADDITIVE ALUMINUM MANUFACTURING WITH FEED GTAW

Using the powered GTAW process to perform additive manufacturing on aluminum plates, this work sought to verify the effect of the variation of pulse frequency on the height of the deposited wall. As a complementary objective, we sought to identify whether the variation in pulse frequency would have the effect of minimizing the overflow of the posterior layers during the additive manufacturing process. In order to carry out this work, a MaxxiTIG 200P AC / DC inverter source was used, regulated for alternating current and pulse frequency adjustment in two conditions that follow: 50 and 200 Hz. The AC wave balance was maintained equal to 50% , that is, the same portion for the positive and negative semicycle. Initially, a welding condition was adjusted that would make it possible to open and maintain the arc on the aluminum plate. After that, the wire was fed constantly and automatically. Three specimens were made for each condition and in each set of passes for the realization of the wall, the same pulse frequency was maintained. After the deposition process, a cross section of the specimens and macrography was performed to analyze the geometric profile of the deposited strands. It was observed that the increase in the pulse frequency provides a greater height of the wall and less width of the cords. Regarding the overflow, the increase in pulse rate provided a reduction in the overflow of the predecessor and posterior cords due to the small deviation in the width of these cords while the height of the wall was increased.