Introduction to welding robot:

Welding Robot With the development of electronic technology, computer technology, CNC and robot technology, automatic welding robot has been used in production since the 1960s. Its technology has become increasingly mature, and its main advantages are as follows:

1) Stabilize and improve the welding quality and reflect the welding quality in numerical form;

2) Improve labor productivity;

3) Improve workers’ labor intensity and enable them to work in harmful environments;

4) Reduces the requirements for workers’ operating skills;

5) The preparation period for product modification and replacement is shortened and the corresponding equipment investment is reduced.

Therefore, it has been widely used in all walks of life.

Features of welding robot:

Spot welding does not have very high requirements for welding robots. Because spot welding only requires point control, there are no strict requirements on the movement trajectory of the welding clamp between points. This is why robots could only be used for spot welding earlier. Spot welding robots must not only have sufficient load capacity, but also must be fast when shifting between points, move smoothly, and position accurately to reduce shifting time and improve work efficiency. How much load capacity the spot welding robot needs depends on the type of welding clamp used. For welding clamps separated from the transformer, a robot with a load of 30 to 45 kg is sufficient. However, on the one hand, this kind of welding clamp has a long secondary cable and a large power loss, which is not conducive to the robot extending the welding clamp into the workpiece for welding; on the other hand, the cable keeps swinging with the movement of the robot, and the cable is damaged quickly. Therefore, the use of integrated welding clamps is gradually increasing. The mass of this welding clamp together with the transformer is about 70kg. Considering that the robot must have sufficient load capacity and be able to send the welding tongs to a spatial position for welding at a large acceleration, heavy-duty robots with a load of 100 to 150kg are generally used. In order to meet the requirements of short-distance and rapid displacement of the welding clamp during continuous spot welding. The new heavy-duty robot adds the ability to complete 50mm displacement in 0.3s. This puts forward higher requirements on the performance of the motor, the computing speed and algorithm of the microcomputer.

Structural design of welding robot hand:

Since the designed welding robot works in a quasi-plane and narrow space environment, in order to ensure that the robot can track the welding seam for automatic welding based on the deviation information of the arc sensor, the designed robot is required to be compact in structure, flexible in movement and stable in work. In view of the characteristics of the narrow space, a small mobile welding robot is developed. According to the motion characteristics of each structure of the robot, the modular design method is used to divide the robot mechanism into three parts: a wheeled mobile platform, a welding torch adjustment mechanism and an arc sensor. Among them, the wheeled mobile platform mainly performs rough tracking of welds due to its large inertia and slow response. The welding torch adjustment mechanism is responsible for accurate tracking of welds, and the arc sensor completes real-time identification of weld deviations. In addition, the robot controller and motor driver are integrated and installed on the robot mobile platform, making it smaller in size. At the same time, in order to reduce the impact of dust on moving parts in harsh welding environments, a fully enclosed structure is adopted to improve system reliability.

Welding robot equipment:

The welding equipment of the spot welding robot uses an integrated welding clamp and the welding transformer is installed behind the welding clamp, so the transformer must be as small as possible. For transformers with smaller capacity, 50Hz power frequency AC can be used, while for transformers with larger capacity, inverter technology has begun to be used to convert 50Hz power frequency AC into 600~700Hz AC, reducing the size of the transformer. After voltage transformation, you can directly use 600-700Hz AC welding, or you can perform secondary rectification and use DC welding. Welding parameters are adjusted by timers, see Figure 1b. The new timer has been microcomputerized, so the robot control cabinet can directly control the timer without the need for additional interfaces. The welding tongs of spot welding robots usually use pneumatic welding tongs. The opening between the two electrodes of the pneumatic welding tongs generally only has two strokes. Moreover, once the electrode pressure is set, it cannot be changed at will. In recent years, a new type of electric servo spot welding clamp has emerged. The opening and closing of the welding clamp is driven by a servo motor, and the encoder feedback allows the opening of the welding clamp to be arbitrarily selected and preset according to actual needs. Moreover, the pressing force between the electrodes can also be adjusted steplessly. This new electric servo spot welding clamp has the following features

Advantages of welding robots:

1) The welding cycle of each welding point can be greatly reduced, because the opening degree of the welding tongs is accurately controlled by the robot. During the movement of the robot between points, the welding tongs can start to close; and after welding a point, the welding tongs open while the robot can move. There is no need to wait for the robot to be in place before the welding tongs close or the robot to move after the welding tongs is fully opened;

2) The opening of the welding clamp can be adjusted arbitrarily according to the condition of the workpiece. As long as no collision or interference occurs, the opening should be reduced as much as possible to save the opening of the welding clamp and the time spent opening and closing the welding clamp.

3) When the welding clamp is closed and pressurized, not only the pressure can be adjusted, but also the two electrodes are gently closed when closing, reducing impact deformation and noise.

Welding Robot With the development of electronic technology, computer technology, CNC and robot technology, automatic welding robot has been used in production since the 1960s. Its technology has become increasingly mature, and its main advantages are as follows: