Suppressing tool chatter with novel multi-layered nanostructures of carbon based composite coatings

Multi-layered nanostructured Cu and Cu–CNx composites synthesized by plasma-enhanced chemical vapour deposition were applied in the clamping area of a milling tool to suppress regenerative tool chatter. Scanning electron microscopy analysis showed a multi-layered nanostructure with excellent conformality, i.e. coating is not only uniform on planar surfaces but also around corners of the substrate. Cu:CuCNx nanostructured multilayers with thicknesses of approximately 0.5:1.6 μm were obtained. With a diameter of 20 mm, the milling tool performed slotting processes at an overhang length of 120 mm. Modal analysis showed that a coating, with a thickness of approximately 300 μm, can add sufficient damping without losing stiffness of the tool, to increase the critical stability limit by 50% or 100% depending on cutting direction.