An additive manufacturing system includes an energy source and a material delivery device. The energy source is configured to direct an energy beam toward a component to form a melt pool. The material delivery device is configured to feed a wire toward the melt pool to deposit material on the component. In some examples, the material delivery device is configured to discharge a current to the wire to disengage the wire from the melt pool. In some examples, the material delivery device is configured to measure an arc voltage between the wire and the component.

Gas-shielded arc welding in which the tip-to-work distance changes is configured so that fluctuations in welding current are curbed while arc length control is maintained. This is achieved with a corrected current calculating unit that includes a first controlling expression where a first gain G1 is multiplied by an instantaneous voltage error value that is the difference between an instantaneous output voltage setting value and an output voltage detection value, and/or a second controlling expression where a second gain G2 is multiplied by an average voltage error value that is the difference between an output voltage setting value and an average output voltage detection value of a pre-set period of time, determines an arc property gain G1 and/or G2 based on a torch position detection value determined by a torch position determinator, and calculates a corrected current based on the first and/or the second controlling expression.

DC arc welding is performed by alternating a short-circuit period and an arc period. The arc period includes first to fourth periods. A welding current is raised to a first current value in the first period, lowered to a second current value with a time slope in the second period, kept at the second current value in the third period, and raised to a third current value then kept at the value in the fourth period. A wire feeding speed is constant throughout the short-circuit period and the arc period. In the second period, a welding output is under constant voltage control. In the third period and the fourth period, the welding output is under constant current control of the welding output.

DC arc welding is performed by alternating a short-circuit period and an arc period. The arc period includes first to fourth periods. A welding current is raised to a first current value in the first period, lowered to a second current value with a time slope in the second period, kept at the second current value in the third period, and raised to a third current value then kept at the value in the fourth period. A wire feeding speed is constant throughout the short-circuit period and the arc period. In the second period, a welding output is under constant voltage control. In the third period and the fourth period, the welding output is under constant current control of the welding output.

The present invention relates to a method for welding a half coil of a reactor, which performs the gas metal arc welding (GMAW) along a half coil temporarily welded to a welding machine body using an automatic welding machine to increase a formation amount of back beads, thereby increasing coupling strength of the half coil, increasing airtightness of a fluid flowing along the half coil, securing uniform welding quality by automatic welding, increasing productivity, and reducing production costs.

The present invention relates to a method for welding a half coil of a reactor, which performs the gas metal arc welding (GMAW) along a half coil temporarily welded to a welding machine body using an automatic welding machine to increase a formation amount of back beads, thereby increasing coupling strength of the half coil, increasing airtightness of a fluid flowing along the half coil, securing uniform welding quality by automatic welding, increasing productivity, and reducing production costs.

Systems, methods, and apparatus to preheat welding wire are disclosed. An example welding assembly for a welding torch includes: a first contact tip configured to conduct welding current to a consumable electrode; a second contact tip configured to conduct preheating current to the consumable electrode; and a cooling body configured to transfer heat from at least the first contact tip to coolant and to conduct the welding current.

Systems, methods, and apparatus to preheat welding wire are disclosed. An example welding assembly for a welding torch includes: a first contact tip configured to conduct welding current to a consumable electrode; a second contact tip configured to conduct preheating current to the consumable electrode; and a cooling body configured to transfer heat from at least the first contact tip to coolant and to conduct the welding current.

The wire feed mechanism includes a feed roll, a pressure roll, a pressure arm, and a pressure mechanism. The feed roll rotates around a rotation axis. The pressure roll is displaceable relative to the feed roll. The pressure arm has a first end and a second end that are separate from each other, and rotatably supports the pressure roll. The pressure mechanism engages with the pressure arm so that a pressure force is applied from the pressure roll to the feed roll with a wire held between the feed roll and the pressure roll. A force-receiving portion is provided at an end of the pressure arm. When the pressure roll presses the feed roll, the pressure mechanism applies a force to the force-receiving portion in a direction that is substantially parallel to the direction in which the wire is fed.

A plasma ejection unit (21) of an arc welding device includes a plasma torch (26), a copper plate (27), a container (28), and a gas supplying unit (29). Plasma gas inside the container (28) is pressurized by argon gas supplied from the gas supplying unit (29), and ejected from first to eighth ejection ports. The plasma gas ejected from the first to eighth ejection ports is concentrated in a concentration area (CA) between vehicle body plates (16-17) to form through holes (40) in the vehicle body plates (16-17), and is separated. The air pressures, in eight areas, of the plasma gas reaching a vehicle body plate (18) are approximately one-eighth of the air pressure of the plasma gas in the concentration area (CA). Accordingly, while the through holes (40) are formed in the vehicle body plates (16-17), no through hole is formed in the vehicle body plate (18).