Decoupling the arc pressure and heat output improves the controllability of the arc. In this study, an innovative torch was successfully developed for this purpose by adding an outer electrode under the orifice to a conventional plasma arc welding (PAW) torch. The arc rooting from the added electrode merges with the main/PAW arc forming a hybrid arc system with two cathodes and one anode. While the major arc is constrained, the added arc is allowing to change the anode heat while the pressure is still primarily controlled by the main arc. The coupling behavior was experimentally studied through analysis arc column image and arc pressure measurement. The results show that the added free arc formed by the outer electrode is fully absorbed and coupled into the constraint arc to form a single hybrid arc. The arc pressure peak value in the hybrid arc is little sensitive to outer free arc current compared with that by adjusting the center constraint arc current. Because the sided outer tungsten electrode is isolated to the center inner tungsten electrode and the cooper nozzle in the arcing torch system, the range of arc current applied by the outer tungsten electrode is large. The torch system provides a novel arc plasma generation method to improve the control precision in manufacturing process.

解耦电弧压力和热量输出改善了电弧的可控性。在这项研究中，为此成功地开发了一种创新的焊炬，方法是在孔口下方向传统的等离子弧焊（PAW）焊炬添加外电极。从添加的电极产生的电弧与主/ PAW电弧合并，形成具有两个阴极和一个阳极的混合电弧系统。在限制主电弧的同时，增加的电弧允许改变阳极热量，而压力仍主要由主电弧控制。通过分析电弧柱图像和电弧压力测量实验研究了耦合行为。结果表明，由外部电极形成的添加的自由电弧被完全吸收并耦合到约束电弧中，从而形成单个混合电弧。与通过调整中心约束电弧电流相比，混合电弧中的电弧压力峰值对外部自由电弧电流几乎不敏感。因为在电弧焊炬系统中，侧面的外部钨电极与中心内部钨电极和铜喷嘴隔离，所以由外部钨电极施加的电弧电流的范围较大。焊炬系统提供了一种新颖的电弧等离子体产生方法，以提高制造过程中的控制精度。