| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface coated cutting tool improved in chipping resistance by suppressing the chipping of the coating layer on a rake face, and also improved in wear resistance of a flank. SOLUTION: In a cutting end mill 1, the surface of a base body 6 is coated with a coating layer 7. The ridge portion, where the rake face 2 crosses the flank 3, forms a cutting edge 4. The thickness T<SB>r</SB>of the coating layer 7 on the rake face 2 is thinner than the thickness T<SB>f</SB>of the coating layer 7 on the flank 3. The coating layer 7 is composed of columnar crystal, and also is composed of two regions in which the average crystal width in the upper region on the surface side of the coating layer 7 is larger than the average crystal width in the lower region on the base body 6 side of the coating layer 7. The ratio of the thickness of the upper region to the layer thickness T<SB>r</SB>of the coating layer 7 on the rake face 2 is smaller than the ratio of the thickness of the upper region to the layer thickness T<SB>f</SB>of the coating layer 7 on the flank 3. The average crystal width of the columnar crystal on the rake face 2 is smaller than the average crystal width of the columnar crystal on the flank 3. COPYRIGHT: (C)2009,JPO&INPIT
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