In wire-arc directed energy deposition (DED), tungsten inert gas (TIG) welding/gas tungsten arc welding (GTAW), which offers high flexibility in deposition conditions and less spatter, are used as primary welding processes. However, in additive manufacturing of complex shapes with TIG welding, it is difficult to achieve uniform and stable fabrication because the wire is fed from a fixed lateral direction to the centered arc heat source. To overcome this problem, a novel rotary TIG torch was developed in this study. The wire was fed from the center of the torch, and the tilted electrode or arc heat source rotated around the wire during deposition, allowing the deposition process to be omnidirectional. In the experiment, the basic characteristics and process window of the rotary TIG were investigated, and single-layer and multilayer depositions were performed with changing torch travel directions to evaluate deposition accuracy and flexibility. In conventional TIG, particularly under the condition of low heat input per material input, the deposited bead position and shape were changed depending on the travel direction, and in multilayer deposition, up to 1 mm deviation of the deposition position was observed. In contrast, in the rotary TIG, beads were deposited uniformly regardless of the travel direction and deposition conditions, and in multilayer deposition, straight walls were obtained, and the deviation in the deposition position was small. The results suggest that the application of the rotary TIG torch to wire-arc DED can achieve highly accurate fabrication with higher flexibility in building conditions.

中文翻译：

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具有同轴送丝和旋转电极的焊枪，用于线弧定向能量沉积

在电弧定向能量沉积 (DED) 中，钨极惰性气体保护焊 (TIG)/钨极气体保护焊 (GTAW) 被用作主要焊接工艺，其沉积条件高度灵活且飞溅较少。然而，在采用TIG焊接进行复杂形状的增材制造中，由于焊丝从固定的横向方向送入中心电弧热源，因此很难实现均匀稳定的制造。为了克服这个问题，本研究开发了一种新型旋转TIG焊枪。焊丝从焊炬中心送入，沉积过程中倾斜的电极或电弧热源围绕焊丝旋转，使沉积过程是全向的。在实验中，研究了旋转TIG的基本特性和工艺窗口，并通过改变割炬行进方向进行单层和多层沉积，以评估沉积精度和灵活性。在传统的TIG中，特别是在每输入材料的热量输入较低的情况下，沉积焊道的位置和形状根据行进方向而改变，并且在多层沉积中，观察到沉积位置的偏差高达1毫米。相比之下，在旋转TIG中，无论行进方向和沉积条件如何，珠子都均匀地沉积，并且在多层沉积中，获得笔直的壁，并且沉积位置的偏差很小。结果表明，将旋转 TIG 焊枪应用于线弧 DED 可以实现高精度制造，并且在建筑条件下具有更高的灵活性。