20. Characterization of Cutting Edge Radius of a Single Crystal Diamond Tool by Atomic Force Microscopy

Single crystal diamond (SCD) is the ideal tool material in ultra-precision machining because of its high hardness, wear resistance, chemical stability, and the ability to sharpen the cutting edge in nanometers. The sub-micron level in the cutting edge profile could affect the accuracy of the fabricated surfaces, since cutting edge radii strongly influence the specific cutting energy, cutting forces, cutting temperature, residual stress in the workpiece. Therefore, cutting edge profile of an SCD tool should be checked periodically. The measurements of cutting edge radii of SCD tools are very difficult because of their geometric features (angles, radius... etc) and their dimensions in the nanometric level. This paper deals with various methods of cutting edge characterization of SCD tool by Atomic Force Microscopy (AFM). The change to measurement of the cutting edge radii has been done based on the methodology of the least square circle fit over cutting edge radius with error minimization in the calculation and determined iteratively.