Seamless Structuring of Large Surfaces
In order to modify the technical function, haptics and optics of workpieces, such as interior components in automotive construction, large surfaces are structured using lasers. Industrial robots were previously seen as too imprecise to do this. Scientists are compensating for the system-related imprecision of the robots by implementing a camera-based intelligent positioning method.
The costs of investing in a conventional system for laser structuring large surfaces can easily exceed a million euros. Industrial robots are approx. 80 percent cheaper, but have been ruled out for laser structuring due to their insufficient positioning accuracy. In order for the shape to be evenly applied with repeating patterns and textures, the laser system has to be repositioned precisely for each repetition. The RoboTex project at the Fraunhofer Institute for Production Technology (IPT) in Aachen has developed an intelligent system for laser structuring large surfaces with high precision, using a commercially available industrial robot.
The scientists are compensating for the system-related imprecision of the robots by implementing a camera-based intelligent positioning method. In the first step, the laser makes markings on the surface to be structured, which will later serve as anchoring points for the texture. The robot must then move the laser to the right position for structuring. Using an integrated camera that identifies both the markings and the structural areas, the imprecision of the robot can be tolerated and its deviation from the intended position recognised. Using this information, the robot's deviated position is recognised before structuring, so that it can be corrected using adaptive path planning, enabling a seamless structuring of the surface. The markings made in the beginning disappear layer by layer in the laser structuring process.
Interface to multi-technology platform
The new system can be integrated in to the Multi-Technology Robot System for Adaptive Manufacturing (MIRA) that was developed by Fraunhofer IPT. Using an adapter plate on the robot head, MIRA bundles several manufacturing technologies such as drilling, polishing or grinding into one laser-protected robot cell. This allows different manufacturing technologies to be integrated into one hybrid manufacturing system, reducing set-up times and downtimes drastically. Besides the different manufacturing technologies, it also contains a 3D digitalisation system, which can be used to assess the quality of the individual process steps without having to readjust clamps. The industrial robot is attached to a linear axis, which allows the use of the entire clamping surface (4 x 2.5 m).