Surface structuring of polycrystalline diamond (PCD) using ultrashort pulse laser and the study of force conditions

Abstract

In the metal working industry, cutting tools for high precision application are usually made from non-conventional super hard materials, for example, diamond (D) and cubic boron nitride (CBN). These materials are composites of geometrically undefined grains embedded in metallic binder. For some special applications, these tools are constructed from one or several cutting edges and guide rails. Typical examples are honing and guided reaming tools for the fine machining of bores. These tools improve the form, dimension and surface quality, as well as the geometrical tolerances of the machined workpieces. The guide rails of the tool play an important role as they usually support the tool shaft in the rotating movement, for example the guiding stones of the honing tool. In the case of dynamic contact, higher demands on material properties such as hardness and wear resistance are necessary. In this study, a polycrystalline diamond (PCD) grade is employed as a new material for guide rails. Contacting surfaces of the PCD guide rails are textured with three defined patterns by a femtosecond laser setup. It is aimed to improve the force conditions by means of changing the contacting conditions. Within this regard, the tribological properties of the three patterns on PCD rails are characterized using a nanotribometer and compared to the conventional guide rails made of cemented tungsten carbides. A force simulation based on the honing processes is built up and conducted to predict the force conditions of each different pattern. At the same time, morphological modification, assessment of surface and microstructural integrity of the structured PCD guide rails are also studied in this work.