Combination of laser surface texturing and PVD coating for cold forming tools

Wear of cold forming dies is a major obstacle for tool making industries, as it causes increased die maintenance cost and scrap rate. Many aspects are involved in tool wear, such as lubrication, contact pressure and surface coating. In order to cope with these wear issues, PVD coatings are widely used to improve hardness, wear resistance and oxidation resistance. On the other hand, Surface texturing is proved to be a promising method for improving tribological performance. The application of certain textures on one of the two surfaces of the sliding pair can entail many positive effects, such as reduction of friction and wear and increase in load capacity. In particular, the laser surface texturing offers a promising concept in terms of industrial exploitability, due to its high degree of automation and integration within traditional fabrication cycles. In this work, the use of laser surface texturing technologies in coupling with thin hard physical vapour deposited coatings is presented. In particular, different approaches were analysed for combining both technologies. The effect of laser texturing parameters on the geometry of the patterns produced on different materials (ceramic coatings and steels) was studied. Finally, wear tests were carried out on different combinations of base steel, PVD coating and laser textured patterns.