Laser Structuring at Triple the Productivity
Car makers currently use a variety of methods to emboss plastic panels for vehicle interiors in the course of a few minutes. However, manufacturing the tools required for this purpose is extremely time-consuming. A new laser machine triples the rate at which these tools are produced while facilitating even more complex structures.
The finer the texture of the plastic surfaces in car interiors are, the closer they come to approximating the appearance of leather or other high-quality materials. It only takes auto suppliers a matter of minutes to fabricate this kind of surface. Producing the metal tools required for this purpose takes significantly longer, usually up to four weeks for the tool structuring itself. The three-dimensional texturing is either etched onto the tool in dozens of individual steps or created by means of a laser process with ablation rates in the region of approximately 1 mm³/min. The eVerest research project saw five companies and three research institutions join forces to radically improve laser structuring technology with resolutions in the micrometre regime. "Our aim was to make the processes much faster while simultaneously achieving even higher texturing quality," says Andreas Brenner from the Fraunhofer Institute for Laser Technology ILT, summing up the project's objectives.
Less scanner dead time, enhanced USP laser power
To optimise the processes, the engineers started out by examining the efficiency of all the components. Significant progress was made by reducing dead times in the scan paths. They eventually succeeded in tripling the throughput using innovative scanner technology developed by Scanlab. An ultrashort pulse (USP) laser was also integrated in addition to the standard nanosecond laser. This made it possible to reduce surface roughness to less than 0.5 µm.
The individual components were incorporated into a machine based on the Lasertec 125 from DMG Mori. The developers had two key goals: firstly, that the machine should be easy to operate, without requiring any specialist expertise in the technologies used, and, secondly, that the number of processes should be reduced to a minimum. The simplicity of the processes represents one of the main advantages over etching, which frequently still relies on the instincts and dexterity of the machine operator. The software plays a key role in making the fully automatic eight-axis machine easy to use. The team at RWTH Aachen University developed special tools that enable users to precisely simulate the desired structures on the surfaces and visualise their appearance in real time.
Rapid laser structuring for multiple applications
The process itself is now being tested in collaboration with partners at Volkswagen, but the potential applications of the core technology extend far beyond the confines of the auto industry. From embossing rollers in the printing industry to large bearings for rotor shafts in wind turbines, structured and functional surfaces are required across a broad variety of sectors. "A detailed understanding of the process is essential whatever the application. The key is to combine this with modifications to the process technology and comprehensive control software," says Brenner, summing up the project team's approach.