US 5,366,522 A · Polycrystalline diamond cutting tool and method of manufacturing the same

Abstract

A polycrystalline diamond cutting tool comprises a tool material of polycrystalline diamond formed by low-pressure vapor deposition, which is bonded to a shank of cemented carbide through a brazing layer. The thickness of the polycrystalline diamond layer is set at 0.1 to 1.0 mm, while that of the brazing layer is set at 10 to 50 .mu.m. The brazing layer is made of a material having a melting point of 950.degree. to 1300.degree. C., which is in the form of an alloy layer containing at least one material selected from metals belonging to the groups IVa, Va, VIa and VIIa of the periodic table and carbides thereof and at least one material selected from Au, Ag, Cu, Pt, Pd and Ni. The polycrystalline diamond cutting tool is improved in heat resistance and tool strength. In order to improve deposition resistance of the cutting tool, the surface roughness of a tool rake face is set to be not more than 0.2 .mu.m in Rmax. A portion of the polycrystalline diamond layer up to a depth of 10 .mu.m from the rake face contains 99 to 100 atomic percent of carbon elements, and 99 to 100% of carbon atoms are diamond-bonded. A surface of the polycrystalline diamond layer which has been in contact with the substrate during formation of the polycrystalline diamond layer defines the rake face, whose surface is subjected to ion beam machining and thereafter treated in the atmosphere at a temperature of 300.degree. to 500.degree. C.

Claims39

Dependent claims

A polycrystalline diamond cutting tool comprising a tool holder, a tool member, and a brazing layer made of a brazing filler mental having a melting point of at least 950.degree. C. and not more than 1300.degree. C., said brazing layer bonding said tool member to said tool holder, said tool member comprising a polycrystalline diamond layer that has been synthesized on a substrate by low-pressure vapor deposition, said polycrystalline diamond layer having a thickness within the range of at least 0.1 mm and not more than 1.0 mm, said tool member having a rake surface and, opposite said rake surface, a bonding surface bonded to said tool holder through said brazing layer, said polycrystalline diamond layer having a grain size distribution that increases from said rake surface to said bonding surface, and wherein diamond grain sizes are within the range of 0.01 .mu.m to 1.0 .mu.m on the side of said rake surface and within the range of at least 5% and not more than 15% of said diamond layer thickness on the side of said bonding surface.

A method of manufacturing a polycrystalline diamond cutting tool having a tool member brazed to a tool holder, comprising the following steps:

(a) providing a substrate having a surface with a roughness of not more than 0.2 .mu.m Rmax;
(b) forming a polycrystalline diamond layer on said substrate surface by low-pressure vapor deposition until said diamond layer has a layer thickness within the range of 0.1 mm to 1.0 mm and wherein a mean grain size of said polycrystalline diamond increases in a direction of crystal growth from said substrate to an outer diamond layer growth surface, wherein said mean grain size is at least 0.01 .mu.m and not more than 1 .mu.m toward said substrate and at least 5% and not more than 15% of said layer thickness of said polycrystalline diamond layer toward said outer growth surface;
(c) removing said substrate from said polycrystalline diamond layer;
(d) cutting said polycrystalline diamond layer into a tool member shape;
(e) selecting a brazing filler metal of an alloy containing at least one metal selected from the group consisting of the groups IVa, Va, via and VIIa of the periodic table and carbides thereof and at least one metal selected from the group consisting of Au, Ag, Cu, Pt, Pd and Ni;
(f) interposing said brazing filler metal between said tool holder and said outer growth surface;
and
(g) heating and melting said brazing filler metal thereby bonding said tool member to said tool holder wherein the polycrystalline diamond layer surface removed from said substrate defines a tool rake face.

5 more elements

A method of manufacturing a polycrystalline diamond cutting tool having a tool member brazed to a tool holder, comprising the following steps:

(a) preparing a substrate having not more than 0.2 .mu.m Rmax;
(b) forming a polycrystalline diamond layer on said substrate surface by low-pressure vapor deposition until said diamond layer has a layer thickness within the range of 0.1 mm to 1.0 mm and wherein a mean grain size of said polycrystalline diamond increases in a direction of crystal growth from said substrate to an outer diamond layer growth surface, wherein said mean grain size is at least 0.01 .mu.m and not more than 1 .mu.m toward said substrate and at least 5% and not more than 15% of said layer thickness of said polycrystalline diamond layer toward said outer growth surface;
c) removing said substrate from said polycrystalline diamond layer;
(d) cutting said polycrystalline diamond layer into a tool member shape;
e) covering said outer growth surface of said tool member shape with at least one material selected from the group consisting of the groups IVa, Va, VIa and VIIa of the periodic table and metal carbides thereof, forming a covering layer on said outer growth surface;
(f) interposing a brazing filler metal containing at least one material selected from the group consisting of Au, Ag, Cu, Pt, Pd and Ni between said tool holder and said covering layer, and
(g) heating and melting said brazing filler metal thereby bonding said tool member shape to said tool holder wherein the polycrystalline diamond layer surface removed from said substrate defines a tool rake face.

4 more elements

Dependencies are inferred from the claim text.

Polycrystalline diamond cutting tool and method of manufacturing the same

Life of this patent

Polycrystalline diamond cutting tool and method of manufacturing the same

Life of this patent

Abstract

Claims39