Laser microstructuring of polished floor tiles

The lobbies of hotels and banks, airport terminals and rail stations are often elegantly paved with polished natural stone, such as granite. While making a pleasant sight, glossy stone floors may become slippery when wet and dirt are brought in on peoples shoes. To prevent people slipping and injuring themselves, the natural stone floors of public buildings need to have a non-slip finish. The Fraunhofer Institute for Material and Beam Technology IWS in Dresden have developed a laser process for this purpose, which does not deteriorate the gloss and color intensity to the tiled floor. Conventionally, polished stone floors are provided with a non-slip or anti-skid finish by a form of suction pads, increasing the friction between shoe soles and the floor. The laser process produces the same effect, but is environmentally harmless and not affected by external influences. The pulsed laser beam is guided by two scanner mirrors and a special optical co nfiguration, allowing the treatment to proceed at extremely high speed and with exceptional precision. The machine carves 8,000 to 10,000 micro-craters per second into the stone slabs. Different degrees of non-slip effect can be achieved by varying the dimensions of the indentations and the distance between them. Depending on the safety each 0.3 to 0.5 millimeters apart. Despite the roughened surface, cleaning the floor is just as easy as before. The process was successfully tested in 1997 with a stationary pilot device. Since last year, it works on an industrial scale, applying the non-slip finish to stone slabs in the production line of a factory. Until recently, existing floors could only be given the conventional chemical treatment but now the available prototype mobile device can provide the non-slip surface finish in situ.