2017 年 83 巻 851 号 p. 16-00573
A linear machining technique using a nanosecond pulsed laser, adaptable for forming a single-point cutting tool made of nano-polycrystalline diamond, was developed. A basic study to find the principal rules of linear machining was conducted by forming an inclined face against the beam axis that is coincided with the Z axis. The face was formed by conducting repeatedly a set of machining processes, comprising linear machining to remove chips and zero-cut machining to remove the residual stock. It was verified through a machining test that the removal depth in the Z direction was independent of the inclined angle of the face. In addition, the stock removal in the Z direction coincided with the sum of the applied depths of cut in the Z direction when the residual stock removal in each machining step was eliminated by the zero-cut machining. These basic rules made it possible to accurately fabricate a convex dimple with a diameter of 0.2 mm, during which the inclined angle of the machined face against the beam axis varied at every position, by repeatedly conducting the set of machining processes. Also, it was verified through the forming test of a single-point cutting tool with a nose radius of 0.4 mm that the linear machining technique enabled the fabrication of the tool with a shape accuracy better than 1 μm and a cutting edge radius of less than 250 nm.