Welding robot mainly consists of two parts: robot and welding equipment.

A robot consists of a robot body and a control cabinet (hardware and software). The welding equipment, for example, arc and spot welding, consists of welding power source (including its control system), wire feeder (arc welding), welding torch and other components.

For intelligent robots should also have sensing systems, such as laser or camera sensors and their control devices. Countries around the world to produce welding robots basically belong to the joint robot, the vast majority of six axes. Among them, 1, 2 and 3 axes can send the end tool to different spatial positions, while 4, 5 and 6 axes to solve the different requirements of the tool attitude.

The mechanical structure of the welding robot body has two main forms: a parallelogram structure and a side-mounted (pendulum) structure.

The parallelogram robot's upper arm is driven by a tie rod. The tie rod and the lower arm form two sides of a parallelogram. Parallelogram robots developed in the early days had a small workspace (confined to the front of the robot), making it difficult to work upside down. However, new parallelogram robots (parallel robots) developed since the late 1980s have been able to expand the workspace to the top, back, and bottom of the robot without the stiffness problems of the mounted robots, and have thus gained popularity. This structure is suitable not only for light but also for heavy robots. In recent years, most of the robots used for spot welding (load of 100 to 150 kg) are of the parallelogram structure type.

The main advantage of the side-mounted (pendulum) structure is the large range of motion of the upper and lower arms, which enables the robot's workspace to reach almost a sphere. Therefore, this robot can work upside down on the frame to save floor space and facilitate the flow of objects on the ground. However, the 2 and 3 axes of this side-mounted robot are cantilevered structures, reducing the stiffness of the robot, which is generally applicable to robots with smaller loads for arc welding, cutting or spraying.

The above two robots each axis are for rotary motion, so the use of servo motors through the cycloid (RV) reducer (1 to 3 axes) and harmonic reducer (1 to 6 axes) drive. Before the mid-80s, for the electric drive of the robot are used DC servo motors, and since the late 80s, countries have switched to AC servo motors.

Because AC motors do not have carbon brushes, good dynamic characteristics, so that the new robot is not only a low accident rate, and maintenance-free time increased greatly, plus (minus) speed is also fast. Some of the load 16kg below the new lightweight robot its tool center point (TCP) of the highest speed of movement up to 3m / s or more, accurate positioning, vibration is small.

At the same time, the robot's control cabinet has been changed to 32-bit microcomputer and new algorithms, so that it has its own optimization of the path of the function, the running trajectory is closer to the trajectory of the demonstration.

Welding robot degrees of freedom selection

The arm and wrist of a welding robot are the basic action parts. The arm of a robot of any design has three degrees of freedom to ensure that the end of the arm can reach any point within its working range. The three degrees of freedom of the wrist are the rotary motion around the three mutually perpendicular axes of space, X, Y, and Z. These are commonly referred to as roll, pitch, and yaw motions.

When the customer procurement and use of welding robots should consider the following aspects:

1, the type of production of welded parts belongs to the nature of multi-species, small batch production;

2, the structural dimensions of the weldments are mainly small and medium-sized welding workpieces, and the material and thickness of the weldments are conducive to the use of spot welding or gas shielded welding welding methods;

3, to be welded blanks in the dimensional accuracy and assembly accuracy to meet the welding robot welding process requirements;

4, and welding robot supporting the use of equipment, such as automated welding equipment and welding positioner should be able to coordinate action with the welding robot online, so that the production rhythm;

Welding robot advantages

With the development of electronic technology, computer technology, numerical control and robotics, automatic welding robots from the 60s began to be used in production, its technology has become increasingly mature, its advantages are mainly the following aspects:

1), stabilize and improve the quality of welding, welding quality can be reflected in the form of numerical values;

2), improve labor productivity.

3), to improve the labor intensity of workers, can work in harmful environments;

4), reduces the requirements for workers to operate the technical requirements;.

5), shorten the preparation cycle of product modification and replacement, and reduce the corresponding equipment investment.