【 Abstract 】 : Robot replacement manual welding has been more and more common, not only high efficiency, good quality, easy to manage is also a reason for enterprises to choose. However, the simple welding robot system has high requirements on the precision of products and assembly of tooling. Some products with low precision cannot meet the actual requirements of the factory by welding robots, so it is necessary to add a welding seam tracking system. Generally, arc tracking can only be used with the function of initial end detection of welding robot. You can test the weld and then weld it, or you can test it and weld it. The starting end detection of the welding robot can be used alone, and only the offset positions of the starting and ending points can be detected. And arc tracking

Weld tracking need not worry, what problems find Rui Cattle!

Robot replacement of manual welding has become more and more common, not only high efficiency, good quality, easy to manage is also a reason for enterprises to choose. However, the simple welding robot system has high requirements on the precision of products and assembly of tooling. Some products with low precision cannot meet the actual requirements of the factory by welding robots, so it is necessary to add a welding seam tracking system.

Generally, arc tracking can only be used with the function of initial end detection of welding robot. You can test the weld and then weld it, or you can test it and weld it. The starting end detection of the welding robot can be used alone, and only the offset positions of the starting and ending points can be detected. Arc tracking can be detected at any position. If it is a right-angle weld, it can be basically detected at the beginning end (too much welding deformation is not ideal). For the thin plates below 2MM, especially for spline welds, most of them use laser as weld seam tracking. The laser tracking is to monitor the laser scanning of the front camera to get weld seam information and feed it back to the robot controller. In the welding process, the robot will automatically modify the trajectory according to the obtained data to complete the welding.

Arc tracking and initial end detection are two surfaces where the welding wire touches the base metal. The front part of the welding wire releases low voltage, and the information is transmitted to the controller through the sensor. Then, after calculation, the location of the welding seam is automatically obtained. When the workpiece position changes, no reprogramming is needed, and the weld position can still be obtained through arc tracking. Therefore, arc tracking and initial end detection are only suitable for fillet welds or lap welds (plate thickness shall be greater than 3mm).

However, laser tracking is more suitable for thin plate, and the accuracy is slightly higher than arc tracking, but laser tracking needs to be installed on the head of welding gun, which will cause certain interference to the product. Therefore, the welding seam tracking system of robot should be selected according to the actual situation of the product.

When the laser fringe irradiates to the surface of the weld, the laser fringe (laser structural light) is formed. After passing through the lens on the sensor, a contour of the weld section is generated on the photosensitive detector, that is, the laser fringe image reflecting the shape of the weld section. The laser fringe image is processed in the visual control to extract the characteristic data of the weld, such as the coordinates of the tracking point, the weld clearance, the wrong side and the sectional area. The vision system calculates the path of the welding gun according to the measured position information of the welding seam, and transmits the path data to the robot. The robot controls the running trajectory in real time to ensure that the welding gun is always aimed at the welding seam. At the same time, the visual system can also be the weld dimension is according to the measured data, the calculations required welding parameters, such as welding speed, the arc voltage, welding current, oscillation amplitude, etc., the welding parameters can be sent via Ethernet to the robot, via the robot control welding speed and welding torch swing, or control power adjust welding parameters, welding machine so as to realize the welding parameter of the adaptive control.