Coatings give machine tools a harder edge
The lifetime of machine tools can be increased dramatically by coating them with diamond, while sensors built into the coating can monitor the wear of the coating. Lothar Schafer and Holger Luthje report on a new generation of machine tools. Industrial competitiveness in the global high-tech market relies on the development of top quality products. Advanced materials and sophisticated machining processes are often needed to bring these new products to market and to manufacture them cost-effectively. A crucial step is to develop machine tools that can process materials as cheaply as possible, while also minimizing the use of chemical lubricants that can harm the environment. Machine tools are now benefiting from the progress that has been made over the last two decades in both physical and chemical vapour deposition. Originally developed for the microelectronics industry, these vacuum coating techniques can also be used to cover machine tools with high-quality coatings that reduce wear and prolong the life of the tool. At the Fraunhofer Institute of Surface Engineering and Thin Films (IST) in Braunschweig, Germany, we have built several prototype tools in collaboration with industrial partners and institutes. Tools coated with diamond have been developed for dry machining lightweight materials, while more efficient machining has been achieved by fabricating "smart"tools with sensors integrated into the coating. They show the potential for using coating technology to meet the increasing demands for machine tools and material processing.