Welding robot gradually replaced the welder's work, although the welding robot is easy to use, but because it is a machine, it will inevitably have some faults, so what are the common faults of welding robot? How to solve this problem, Shandong ellite Zhongshun welding robot manufacturer will answer for you.
1. The welding deviation may be due to the problem of welding position or welding gun; first consider whether TCP is accurate, and then adjust it.
2. Undercut may be caused by improper selection of welding technical parameters, incorrect angle of welding torch or incorrect position information of welding gun; proper adjustment of power can change welding process parameters, adjust the posture development of welding gun and relative important position between welding gun and workpiece
3. The appearance of the air hole may not be well protected by gas. If the primer of the workpiece is too thick or the protective gas is not dry enough, the corresponding adjustment can be made
4. Excessive spatter may not be suitable for the selected welding parameters, which is caused by the external gas composition www.amital-nechasim.com or the wire elongation is too long; the power can be adjusted to change the size of the welding parameters, and the ratio adjusting device can adjust the gas ratio of the mixed gas to adjust the relative position between the cutting torch and the workpiece;
5. The weld and the end of the weld are cooled to form an arc crater. When programming, the submerged arc pit function is added in the work step, which can be fully filled.
6. Shot. It may be due to assembly deviation of workpiece or inaccuracy of welding gun TCP; the assembly can be checked or corrected;
7. When the arc fault, not the arc. It may be due to no contact with workpiece or over welding process parameters; manual line, adjust distance and welding torch or properly adjust process parameters;
8. If there is an arc fault, the arc cannot be started. It may be because the welding wire can not contact the workpiece or the process technical parameters are too small.
1、 Some common phenomena of welding robot welding
Carbon dioxide gas shielded welding is commonly used in robot welding. Welding defects such as welding deviation, undercut and air hole are generally found in the welding process. The specific analysis is as follows:
(1) The welding deviation may be due to the incorrect position of welding or the problem of welding gun searching. At this time, it is necessary to consider whether TCP (welding torch center point position) is accurate and adjust it. If this happens frequently, it is necessary to check the zero position of each axis of the robot and correct the zero again.
(2) The undercut may be due to improper selection of welding parameters, incorrect angle of welding gun or incorrect position of welding gun. The welding parameters can be changed by properly adjusting the power, the posture of welding gun and the relative position of welding gun and workpiece.
(3) The porosity may be due to poor gas protection, too thick primer or insufficient drying of protective gas, which can be treated by corresponding adjustment.
(4) Excessive spatter may be due to improper selection of welding parameters, gas composition or too long wire extension length. The welding parameters can be changed by properly adjusting the power, adjusting the gas proportioner to adjust the proportion of mixed gas, and adjusting the relative position of welding gun and workpiece.
(5) A crater is formed at the end of the weld after cooling, which can be filled by adding the function of submerged arc pit in the working step during programming.
2、 Common faults of welding robot
(1) There was a gun collision. It may be due to the assembly deviation of the workpiece or the TCP of the welding gun is not accurate. You can check the assembly or correct the TCP of the welding gun.
(2) Arc fault occurs, no arc ignition. It may be because the welding wire does not contact the workpiece or the process parameters are too small, the wire can be manually fed, the distance between the welding gun and the weld, or the process parameters can be adjusted appropriately.
(3) Protection gas monitoring alarm. If the cooling water or protective gas supply is faulty, check the cooling water or protective gas pipeline.
3、 Influence of welding workpiece on robot welding
At present, most welding robots use teaching programming, which requires that the assembly quality and accuracy of the workpiece must be consistent.
The application of welding robot should strictly control the preparation quality of parts and improve the assembly accuracy of welding parts. The surface quality of parts, groove size and assembly accuracy will affect the effect of seam tracking. The following aspects can be used to improve the quality of parts preparation and assembly accuracy of weldments.
(1) The special welding process of welding robot is compiled, and the part size, weld groove and assembly size are strictly regulated. The tolerance of general parts and groove size is controlled within ± 0.8mm, and the assembly dimension error is controlled within ± 1.5mm. The probability of weld defects such as porosity and undercut can be greatly reduced.
(2) The assembly tooling with high precision is used to improve the assembly accuracy of weldments.
(3) The weld shall be cleaned and free of oil, rust, welding slag, cutting slag and other impurities, and weldable primer is allowed. Otherwise, the success rate of arc striking will be affected. The locations welding is changed from welding rod welding to gas shielded welding, and the spot welding parts are polished to avoid residual slag shell or air hole due to positioning welding, so as to avoid the instability of electric arc and even spatter.
4、 Influence of robot welding positioner and fixture on welding
1) The relative position accuracy of welding seam should be less than or equal to 1 mm.
2) Because the weldments are usually assembled and welded by several simple parts, and the assembly and positioning welding of these parts are carried out in sequence on the welding fixture, so their positioning and clamping are carried out separately.
3) The positioning of robot welding fixture must be consistent before and after the process.
4) Due to the large deflection angle of the positioner, the robot welding fixture should avoid using the movable manual bolt as far as possible.
5) The robot welding fixture should adopt fast clamping parts as far as possible, and need to be equipped with hole platform. In order to compress the quick clamping.
6) Different from the common welding fixture, the robot welding fixture can weld the workpiece on its side as well as the front side, which can be extended infinitely.
The above six points are the main differences between robot welding fixture and ordinary welding fixture, which have a direct impact on the quality of robot welding.
5、 Influence of welding wire on welding process of welding robot
The robot can choose welding wire in barrel or in coil according to the need. In order to reduce the frequency of changing welding wire, the robot should choose barreled welding wire. However, due to the use of barreled welding wire, the feeding hose is very long and the resistance is high, which requires high quality of welding wire such as stiffness. When the welding wire with poor copper plating quality is used, the copper plating on the surface of the welding wire will reduce the volume of the pipe due to friction, and the resistance will increase when the wire is fed at high speed. The welding wire can not be sent out smoothly, resulting in shaking, which makes the arc unstable and affects the weld quality. When it is serious, the robot will be stopped due to the jamming phenomenon, so the welding wire guide pipe should be cleaned in time.
6、 Summary of robot operator programming skills
1) Choose reasonable programming welding sequence. In order to reduce the welding deformation and the length of the welding torch path, the welding sequence is established.
2) The welding torch space transition requires short, smooth and safe moving track, and gun collision is not allowed in the process.
3) Optimize welding parameters. In order to obtain the best welding parameters, the working specimens are made for welding test and procedure qualification.
4) Reasonable positioner position, welding torch posture, welding torch relative to the joint position. After the workpiece is fixed on the positioner, if the welding seam is not the ideal position and angle, it is required to adjust the positioner continuously during programming to make the welding seam reach the horizontal position one by one according to the welding sequence. At the same time, the position of each axis of the robot should be adjusted continuously to reasonably determine the position of the welding gun relative to the joint, the angle and the extension length of the welding wire. After the position of the workpiece is determined, the position of the welding gun relative to the joint is observed by the programmer's eyes, which is difficult. This requires programmers to be good at summarizing and accumulating experience.
5) Insert the cleaning procedure in time. After a certain length of welding procedure is compiled, the cleaning procedure should be inserted in time, which can prevent welding spatter from blocking welding nozzle and conducting nozzle, ensure the cleanness of welding gun, improve the service life of nozzle, ensure reliable arc striking and reduce welding spatter.
6) In general, the program can not be completed in one step. It is necessary to check and modify the program, adjust the welding parameters and welding torch posture during the welding process of the robot, so as to form a good program.
7、 The influence of enterprise internal standard management on the use of equipment
Strictly control the robot operator's specification and operation process, strengthen the maintenance of welding process, can reduce the average daily use of consumable parts such as nozzle, conductive nozzle, etc. In addition, regular inspection and maintenance of the robot system can effectively improve the service life of components.
High quality managers, technicians and operators are the necessary conditions for the robot to give full play to its efficiency. The use of welding robots in an enterprise depends largely on people (in fact, they are robot application Engineers), so it is really important to ensure that there is a stable working team.