Laser Seam Tracking Sensor For Wind Turbines

Count on our laser seam tracking welding sensors if you want to upgrade your automated welding process, increase quality of your welded products, improve welding efficiency and decrease any costs, risks or unnecesary waste.

In such macroscopic terms, it may seem faintly absurd to claim that a technology as specialised as laser seam tracking has a meaningful role to play, there are significant benefits available if the technology is exploited fully. While laser seam tracking may not be the primary mover in energy saving, it enables other advances in welding which do directly address the issue.

Offshore wind installations are largely composed of laser seam tracking sensor for wind turbines steel structures. Producing these efficiently is important for their overall carbon footprint. The efficiency of arc welding power sources has already taken a leap forward with the replacement of mains frequency transformer based units by high frequency inverters using modern power transistors and high-speed electronic controls. Having made the power source itself much more efficient, the next and more difficult step is to improve the efficiency of the welding process.

Considering that joining two pieces of metal together by welding involves melting the interface between them to allow a single molten puddle to be formed and then solidifying the same so that two parts become one, then clearly significant heat is involved. The weld area has to be heated above melting point, around 1500°C for steel, and then allowed to cool back to ambient with the heat mostly radiating to the environment. Any way of reducing the amount of heat used is not only beneficial in general environmental terms but also in specific welding terms, for example, by reducing distortion.

In the case where two parts are butted together, then the objective could be to minimise the heat input by melting only very thin slices of the parent material on either side of the interface. To achieve this, application of heat has to be precisely controlled and it's easy to see how advanced sensing of the actual joint position and precise control of heat delivery is required. So in general terms, the benefits of sensing the joint position are obvious.

Tactile seam tracking
As the name suggests, tactile sensors physically contact the weld seam using a contact probe. As the torch position changes relative to the workpiece, the probe deflects in the opposite direction and the controller makes adjustments to return the torch to its original position. Tactile seam tracking systems are best suited for weld seams with large, distinct geometry. If the weld seam is too small, the probe can lose contact with the seam and run the welding torch off track.
 

Through arc seam tacking
Trough arc seam tracking systems use feedback from voltage, amperage, and wire feed speed sensors to identify changes in torch position. For example, if we were welding down the center of a fillet joint and began to drift to one side, the torch to work distance would decrease causing an increase in arc amperage (cv welding). For this method of tacking to work, the welding torch must oscillate back and forth perpendicular to the weld seam. In doing so, the system is continually making a comparison of welding amperage on the left and right side of the weld seam; between the two amperage peaks must lie the center. Through arc tracking systems are best suited for weld seams with large, distinct geometry such as large bevel and fillet welds.
 

Laser vision seam tracking
Laser vision seam tracking demonstration with column and boom welder systemlaser vision seam tracking systems use a laser ribbon which is projecting onto the surface of the part creating a distinct laser line across the weld seam. The laser line is then viewed at a slight angle using a camera. The result is a line profile that exactly matches the geometry of the weld seam. A reference point is then created on the line profile and the controller will make any necessary movements to keep this reference point in the same position relative to the welding torch. Laser vision systems have a very high resolution allowing them to reliably track both large and small weld seams. 

The use of laser seam tracking sensor for wind turbines beam welding with robotic manipulators is expanding towards wider industrial applications as the system availability increases with reduced capital costs. Conventionally, laser welding requires high positioning and coupling accuracy. Due to the variability in the part geometry and positioning, as well as the thermal deformation that may occur during the process, joint position and fit-up are not always acceptable nor predictable a-priori if simple fixtures are used. This makes the passage from virtual CAD/CAM environment to real production site not trivial, limiting applications where short part preparations are a need like small-batch productions. Solutions that render the laser welding operations feasible for production series with non-stringent tolerances are required to serve a wider range of industrial applications.

Such solutions should be able to track the laser seam tracking sensor for wind turbines as well as tolerating variable gaps formed between the parts to be joined. In this work, an online correction for robot trajectory based on a greyscale coaxial vision system with external illumination and an adaptive wobbling strategy are proposed as means to increase the overall flexibility of a manufacturing plant.

The developed solution employed two control loops: the first is able to change the robot pose to follow varying trajectories; the second, able to vary the amplitude of circular wobbling as a function of the gap formed in butt-joint welds. Demonstrator cases on butt-joint welds with 301 stainless steel with increased complexity were used to test the efficacy of the solution. The system was successfully tested on 2 mm thick, planar stainless-steel sheets at a maximum welding speed of 25 mm/s and yielded a maximum positioning and yaw-orientation errors of respectively 0.325 mm and 4.5°. Continuous laser seam tracking sensor for wind turbines could be achieved with up to 1 mm gaps and variable seam position with the developed control method. The acceptable laser seam tracking sensor for wind turbines quality could be maintained up to 0.6 mm gap in the employed autogenous welding configuration.

Laser seam tracking sensor for wind turbines guidance is a technique in which the welding torch and the welding wire are precisely positioned along the welding gap. When aligning the weld metal to the gap, various tolerances play a role that can influence the dimensions, geometry and position of the weld gap in space.

Even if the gap is laid out straight in the design, in practice it can be uneven and show variations in the width and height of the opposite edges. These variations can be caused by various factors such as the type of fixture or the dead weight of the components.

During the welding process, another effect occurs that can hardly be compensated for by design measures: Namely, thermal distortion. To compensate for these effects, the technique of laser seam tracking sensor for wind turbines was developed. There are various methods of weld seam guidance, although classical approaches are used less frequently today.

A traditional method is to guide the welding torch through a gap using a mechanical pin. However, this method is rarely used nowadays due to its susceptibility to interference (e.g. pin clamping) and its limited applicability to simple geometries. In addition, it does not provide any information about the height of the seam.

The state of the art today consists of optical sensors that detect the geometry and position of the seam without contact before the welding process. Point laser rangefinders with moving beam guidance have been used in some cases, but laser seam tracking sensor for wind turbines are becoming more common. These sensors capture 3D profiles of the gap in front of the welding torch.

In combination with special seam tracking software, the data is evaluated and the optimum position (in the x- and z-plane) is transmitted to the axis control of the welding system or welding robot. As a result, the optimum position of the laser seam tracking sensor for wind turbines can be achieved at any time, even if heat distortion occurs.

Suzhou Full-v was founded in 2019 and has served thousands of users both domestically and internationally, gaining unanimous recognition from users. The Full-v 3D laser intelligent weld seam tracking system has achieved full coverage matching among mainstream robot manufacturers both domestically and internationally, and has the characteristics of simplicity, reliability, and widespread use. The company is committed to providing open and customized optoelectronic sensor equipment and technical services, always prioritizing product quality and user experience. With a spirit of continuous improvement as a craftsman, we provide customers with reliable and stable products.