Fraunhofer Institute for Production Technology IPTResearch Project "GroRoLas3D"
The aim of the "GroRoLas3D" project was to develop a system solution for the cost-effective, large-format laser structuring of free-form, metallic-reflective component surfaces using a conventional industrial robot.
Position accuracy due to position markings and image analysis algorithms
The project built on the results of the "RoboTex" project, which already demonstrated how an industrial robot could be used to laser structure matt and painted surfaces on a large scale. To ensure the required position accuracy for seamless laser structuring, a laser first introduced position markings onto the component surface. These markings were detected with the camera of the beam guidance system located on the robot.
Using the camera images and intelligent image analysis algorithms, the system evaluates the markings in terms of their position, size, orientation and geometric distortion. Position deviations of the robot from the surface could be calculated using this information and the tool path planning for the laser structuring could be adapted accordingly.
Compensation of reflection signals and new strategies for referencing
Image acquisition is much more difficult with reflective and strongly curved surfaces than it is with matt surfaces. Diffuse lighting conditions and an insufficient depth of focus over the entire image field make it almost impossible to detect the laser markings on such surfaces with the existing system solution. This deficit is a significant obstacle to transferring and implementing this technological approach into industrial production environments.
Within the project "GroRoLas3D", the Fraunhofer IPT investigated robot-based technology and continue to develop the existing system solution for automated use in industrial production. To this end, the researchers first developed intelligent software-based algorithms to compensate for the disturbing reflection signals in combination with an adapted polarization illumination and then implemented them into the existing software solution. To further improve the optical image quality, the camera system of the beam guidance system was also modified. At the same time, the researchers examined the use of new marking and referencing strategies to make the robot-based laser structuring process more robust and, at the same time, faster.
Cost reduction for laser structuring by up to 80 percent
With the "GroRoLas3D" project, the Fraunhofer IPT developed a solution to reduce the investment costs for a large laser structuring system by up to 80 percent, even for large-area components with reflective, strongly curved surfaces. Thus, laser structuring of large-format components could be worthwhile for a larger number of companies.
The project was funded by the Federal Ministry for Economic Affairs and Climate Action (BMWK).