Cutting tool having partially-removed film formed thereon

Abstract

The present invention relates to a cutting tool, which performs, like a drill or a ball end mill, cutting while rotating in a state in which the center of the tip end is in contact with a work material, and includes a wear-resistant layer formed at the tip end thereof, wherein a portion of the wear-resistant layer is selectively removed through tip end polishing from the center of the tip end of the drill or the ball end mill to a predetermined area, so as to restrain micro-brittle wear generated in an ultra-low speed region, and thus remarkably improving the cutting lifespan of the cutting tool such as the drill or the ball end mill.

1 . A cutting tool formed in a columnar shape to cut a work material by being rotated while a center of a tip end thereof is in contact with the work material, wherein
 the base material for the tip end of the cutting tool is a sintered alloy,   a wear-resistant layer is formed on the tip end, and   a portion of or the entirety of the wear-resistant layer which is formed within a distance of 0.01 R to 0.8 R (R: a radius of the column-shaped tool) from a center of the tip end is removed.   
     
     
         2 . A cutting tool formed in a columnar shape to cut a work material by being rotated while a center of a tip end thereof is in contact with the work material, wherein
 the tip end comprises one or more detachable and indexible inserts,   the inserts each have a sintered alloy as a base material,   a wear-resistant layer is formed on a surface of each insert, and   a portion of or the entirety of the wear-resistant layer formed on a clearance surface of the insert fastened within a distance of 0.01 R-0.8 R (where, R is a radius of the column-shaped tool) from the rotation center of the tip end is removed.   
     
     
         3 . The cutting tool of  claim 1  or  2 , wherein the cutting tool is a drill or a ball end mill. 
     
     
         4 . The cutting tool of  claim 1 , wherein the wear-resistant layer is formed in a single-layered or a multi-layered thin film. 
     
     
         5 . The cutting tool of  claim 1 , wherein the wear-resistant layer comprises one or more layers of the thin film which comprises
 at least one metallic element selected from elements of IVa, Va or VIa group in the periodic table, Al or Si, and   at least one non-metallic elements selected from N, C, or O.   
     
     
         6 . The cutting tool of  claim 1 , wherein the wear-resistant layer comprises a TiCN layer or Al 2 O 3  layer. 
     
     
         7 . The cutting tool of  claim 2 , wherein the cutting tool is a drill or a ball end mill. 
     
     
         8 . The cutting tool of  claim 2 , wherein the wear-resistant layer is formed in a single-layered or a multi-layered thin film. 
     
     
         9 . The cutting tool of  claim 2 , wherein the wear-resistant layer comprises one or more layers of the thin film which comprises
 at least one metallic element selected from elements of IVa, Va or VIa group in the periodic table, Al or Si, and   at least one non-metallic elements selected from N, C, or O.   
     
     
         10 . The cutting tool of  claim 2 , wherein the wear-resistant layer comprises a TiCN layer or Al 2 O 3  layer.