With the development of automatic welding technology, more and more robot workstations are used in practical engineering. In a welding robot workstation, the controller and robot body are its core components. The body is generally in the form of 6-axis joint, with high structural rigidity and load capacity. The materials used are not radioactive and corrosive, and the service life is generally 10 years Above. Generally, the joint axis adopts AC servo motor to provide driving force, has advanced digital path measurement system, can provide position information, so that it has high welding accuracy, and the error of repeated positioning accuracy can be controlled within 0.1mm. In addition, the system also includes the power-off braking device, which can provide digital control technology for the use of safety. The digital bus is used to connect all parts, and the computer is used for unified control, which can effectively resist the electromagnetic field dry guarantee of the distribution system. The whole system with full disturbance ensures the welding in reproduction. The central processing unit is designed with multiprocessor, which has strong stability and expandable function, and can ensure the track accuracy in high-speed operation. The system includes a teaching device with a friendly operation interface, which is convenient for the operator to learn and use. The key parameters of welding process can be displayed in the operation interface to realize visual control. In addition, the electric control cabinet and operating system have dust-proof treatment measures, or a special control room is set to ensure the reliable operation of the system.

2. Application of welding power supply

The application of welding power supply should give priority to international advanced brands, such as OTC welding machine, so as to improve the matching of the process. When selecting the welding power supply, pay attention to the matching with the control system interface. Generally, advanced products have welding expert parameter system, which can display welding parameters digitally. The main data is input by the teaching device, and can be corrected online at any time in the welding production process. The advanced technology products have a high success rate of arc striking, which can ensure the welding quality. The arc striking can fill the arc crater without bulge. The accuracy of covering and remelting, appearance weld and weld droplet separation is high. Using its parallel swing function, the weld can be quickly and effectively identified and filled. The welding gun used shall be free of electric leakage and oil leakage. Generally, coil or barrel welding wire is used, and the wire feeding speed can reach 0 ~ 24m / min. Due to the large welding wire specification of welding robot, when selecting the power supply specification, ensure that its temporary load rate can reach *.

3. Application of gantry

Gantry is the external axis walking part of the automatic welding robot. This part of structure is the key to expand the scope of robot work. At present, the robot workstations used in the project are all external walking frames equipped with the robot body. The control function of this part is in the charge of the control system, and the integrated control mode is adopted to ensure that the external axis movement and the body movement are coordinated. In the system, the robot body is usually hung upside down on the gantry, so that the welding gun has high accessibility. In order to ensure the welding accuracy when the external shaft is moving, it is necessary to adopt the components of the international advanced brand such as guide rail, bearing and gear, and equip the service motor and reducer with superior performance, and take the lubrication, dust-proof and splash proof protection measures for the guide rail. When the external axis is running, the robot body should be stable to avoid shaking and shaking, and the average repetition accuracy error should be controlled within 0.2mm.

4. Software and sensor system applications

In the application of software and sensing system, the functions of operation software and arc welding software package used by automatic welding robot workstation are relatively complex, including the following aspects: (1) teaching programming function; (2) off-line programming function; (3) database storage function; (4) data processing and calling function; (5) self diagnosis function; (6) breakpoint continuous welding function; (7) Multi layer and multi-channel welding function; (8) parameter real-time adjustment function; (9) longitudinal and lateral swing function; (10) linkage control function between robot and external axis; (11) sensing and tracking function. In order to make the system have high expansibility, the system should include many kinds of functional interfaces, including serial control interface, analog interface, digital interface, printer interface, LAN interface and domain bus system interface. Among them, the functions of the sensor system mainly include arc tracking, wire contact location and laser tracking. During the operation of the system, the arc tracking function can automatically correct the deviation between the programmed position of the weld and the actual position by detecting the change of the welding voltage and current. The welding wire contact locating function can find the starting point of the weld. Laser tracking function has both of the above two functions, and has high anti-interference ability, but the cost of laser tracking is high, which can be reasonably selected according to the actual situation of the project.

5. Application and development trend of automatic welding equipment

In general, in the manufacturing process of construction machinery, the application of automatic welding equipment is mainly affected by the robot body, controller, sensor system, welding power supply and external machines and tools. Due to the strict requirements of the manufacturing precision of the workpiece in the construction machinery manufacturing, in the process of applying the automation equipment, it is necessary to ensure the matching of the equipment and the process, set the welding parameters reasonably according to the actual situation of the project, and make full use of its self diagnosis function to adjust and repair the parameters. At present, there is still a large space for improvement of automatic welding equipment. In the future application and development process, problems such as real-time tracking of welds, low efficiency of locating, manual backing when the gap between welds is large, and repair welding after automatic welding should be solved, so as to further improve the automation and intelligence of the equipment.