Patent ID: 6337000
Filing Date: 2002-01-08
Classification: B23B,C23C,F16C,Y10T

Abstract:
A method of forming a diamond-like carbon film on a guide bush substantially in a cylindrical shape, having a center bore penetrating through an entire length thereof along a longitudinal axial direction comprising:an outer taper surface and slots for providing elasticity thereto, formed at one end thereof in the longitudinal axial direction; a threaded section formed at the other end thereof for being attached into a column of an automatic lathe; and an inner surface for holding a workpiece, formed at an inner radius of a portion where the other taper surface is formed, wherein the workpiece inserted in the center bore is held by the inner surface rotatably and slidably in the longitudinal axial direction in close proximity of a cutting tool, when the guide bush is attached to the automatic lathe, and the inner surface is provided with a cemented carbide alloy containing at least cobalt, said method comprising: a step of removing cobalt contained in the surface of the cemented carbide alloy by etching and removing also marks caused by a grinding process; a step of forming an intermediate layer made of a constituent material of a target on the surface of the cemented carbide alloy by means of a sputtering method after placing the guide bush and the target in a vacuum vessel such that the center bore of the guide bush is disposed opposite to the target, and evacuating the vacuum vessel before introducing argon gas thereinto; a step of disposing the guide bush with the intermediate layer formed thereon in the vacuum vessel such that an electrode is inserted inside the center bore thereof; and a step of forming the diamond-like carbon film on the surface cemented carbide alloy formed on the inner surface of the guide bush by evacuating the vacuum vessel before introducing a gas containing carbon therein, and causing a plasma to be generated inside the center bore by applying a DC voltage of RF electric power to the guide bush while keeping the electrode grounded.