An arc welding robot is an industrial robot used for automatic arc welding tasks, primarily encompassing fusion welding and non-fusion welding operations. As scientific technology advances, these arc welding robots are evolving towards intelligent automation.
The system of an arc welding robot mainly comprises an operating unit, control system, teaching pendant, arc welding system, and related safety equipment. In fact, this system essentially forms a robotic welding workstation.
The structure of the arc welding robot manipulator is similar to that of a general-purpose industrial robot, with the main difference being the end effector – the welding gun.
The manipulator typically has 3-5 or more degrees of freedom, and a 6-degree-of-freedom robot can ensure any spatial position and posture of the welding gun.
The control system of the arc welding robot is fundamentally similar to that of a general-purpose industrial robot in terms of control principles, functions, and composition.
It adopts a hierarchical control system structure, generally divided into two levels: the upper level has a storage unit, can achieve repetitive programming, store multiple operation procedures, and is responsible for management, coordinate transformation, trajectory generation, etc.
The lower level consists of several processors, each responsible for controlling the motion of a joint and detecting its state, offering good performance and facilitating high-speed, high-precision control.
Also, the control of peripheral devices of the arc welding robot, such as workpiece positioning clamping, displacement, protective gas supply cut-off, etc., have separate control devices.
They can be programmed independently and can exchange information with the robot control device, allowing the robot control system to achieve coordinated control of all operations.
The argon arc welding system is the core equipment for completing arc operations, mainly composed of welding power supply, wire feeder, welding gun, and gas cylinder.
Due to the need for parameter selection (such as arc voltage, welding current, wire feed speed, etc.) in the argon arc welding robot’s power supply and wire feeder equipment, these must be directly controlled by the robot controller.
Safety equipment is crucial for the safe operation of the arc welding robot system. It mainly includes protections such as overheat self-disconnection of the drive system, action limit position power off protection, overspeed self-disconnection, workspace interference self-disconnection of the robot system, and manual emergency power off.
These protections are essential for safeguarding the robotic system, personnel, and peripheral equipment. The end effector of the robot is also equipped with various tactile or proximity sensors, which can stop the robot from working when it approaches the workpiece too closely or encounters a collision.
Arc welding processes are significantly more complex than spot welding, necessitating precise control of the wire feed end’s trajectory, the welding torch’s posture, and the welding parameters.
Therefore, in addition to the general functions mentioned earlier, robots used in arc welding must possess capabilities specifically tailored to meet these requirements.
Theoretically, a five-axis robot can be used for arc welding. However, it may encounter difficulties when dealing with complexly shaped weld seams. Therefore, unless the weld is simple, it’s preferable to opt for a six-axis robot.
Robots designed for arc welding are characterized by their ability to perform long-term welding tasks, ensuring high productivity, quality, and stability in the welding process.
The widespread adoption of argon arc welding techniques across various industries has led to the extensive use of argon arc welding robots in the manufacturing of automobiles and their parts, motorcycles, construction machinery, railway locomotives, and more.
