Surface decarburization of a drill bit having a refined primary cutting edge
AssigneeRogers Tool Works, Inc.
InventorsRobert W. Britzke, Jimmy Eason, Zhigang Fang
Life of this patent
Estimating the term…
Abstract
A cutting tool is decarburized by placing the tool in a protective environment, heating in this environment to a temperature of 600.degree.-1100.degree. C., and maintaining this temperature for a period of 15-120 minutes. The cutting tool may be a cemented carbide microdrill which contains primary cutting edges which form an angular surface on the forward end of a rake surface at the cutting tip, and a radius surface which extends from the angular surface to a flank surface which extends from an outer diameter of the cutting tip to an axis of symmetry of the tool.
Claims7
A method of surface decarburizing a cemented carbide cutting tool, comprising the steps of:
- placing the cutting tool in a protective environment;
- heating the cutting tool to an elevated temperature of about 800.degree. C. while the cutting tool is in said protective environment;
- and
- maintaining the cutting tool at said elevated temperature for a time of about 60 minutes, wherein said protective environment comprises a controlled partial pressure of decarburizing gas.
A method of surface decarburizing a cemented carbide cutting tool, comprising the steps of:
- placing the cutting tool in a protective environment;
- heating the cutting tool to an elevated temperature of about 800.degree. C. while the cutting tool is in said protective environment;
- and
- maintaining the cutting tool at said elevated temperature for a time of about 60 minutes, wherein said protective environment is a gas selected from the group consisting of hydrogen, carbon dioxide, oxygen and mixtures thereof.
A method of surface decarburizing a cemented carbide microdrill, comprising the steps of:
- placing the microdrill in a protective environment;
- heating the microdrill to an elevated temperature of about 800.degree. C. while the microdrill is in said protective environment;
- and
- maintaining the microdrill at said elevated temperature for a time of about 60 minutes, wherein said protective environment comprises a controlled partial pressure of decarburizing gas.
A method of surface decarburizing a cemented carbide microdrill, comprising the steps of:
- placing the microdrill in a protective environment;
- heating the microdrill to an elevated temperature of about 800.degree. C. while the microdrill is in the protective environment;
- and
- maintaining the microdrill at said elevated temperature for a time of about 60 minutes, wherein said protective environment is a gas selected from the group consisting of hydrogen, carbon dioxide, oxygen and mixtures thereof.
A method of surface decarburizing a cemented carbide microdrill, wherein said microdrill includes:
- a drill body having a cutting tip, an axis of symmetry, and a plurality of flutes, wherein said flutes have a rake surface at said cutting tip, and
- said cutting tip includes a plurality of side blades between said flutes and joined at a web, a plurality of flank surfaces extending from an outer diameter of said cutting tip to said axis of symmetry and a plurality of primary cutting edges at the intersection of said flank surfaces with said rake surfaces,
- the method comprising the steps of:
- refining said primary cutting edges such that a radius surface extends from said flank surfaces to said rake surfaces;
- placing the microdrill in a protective environment;
- heating the microdrill to an elevated temperature of between 600.degree. C. and 1100.degree. C. while the microdrill is in the protective environment;
- and
- maintaining the microdrill at said elevated temperature for a time of between 15 and 120 minutes.
A method of surface decarburizing a cemented carbide microdrill, wherein said microdrill includes:
- a drill body having a cutting tip, an axis of symmetry, and a plurality of flutes, wherein said flutes have a rake surface at said cutting tip, and
- said cutting tip includes a plurality of side blades between said flutes and joined at a web, a plurality of flank surfaces extending from an outer diameter of said cutting tip to said axis of symmetry and a plurality of primary cutting edges at the intersection of said flank surfaces with said rake surfaces,
- the method comprising the steps of:
- refining said primary cutting edges to form an angular surface on the forward end of said rake surfaces;
- placing the microdrill in a protective environment;
- heating the microdrill to an elevated temperature of between 600.degree. C. and 1100.degree. C. while the microdrill is in the protective environment;
- and
- maintaining the microdrill at said elevated temperature for a time of between 15 and 120 minutes.
A method of surface decarburizing a cemented carbide microdrill, wherein said microdrill includes:
- a drill body having a cutting tip, an axis of symmetry, and a plurality of flutes, wherein said flutes have a rake surface at said cutting tip, and
- said cutting tip includes a plurality of side blades between said flutes and joined at a web, a plurality of flank surfaces extending from an outer diameter of said cutting tip to said axis of symmetry and a plurality of primary cutting edges at the intersection of said flank surfaces with said rake surfaces,
- the method comprising the steps of:
- refining said primary cutting edges to form an angular surface on the forward end of said rake surface, and a radius surface that extends from said angular surface to said flank surface;
- placing the microdrill in a protective environment;
- heating the microdrill to an elevated temperature of between 600.degree. C. and 1100.degree. C. while the microdrill is in the protective environment;
- and
- maintaining the microdrill at said elevated temperature for a time of between 15 and 120 minutes.
Dependencies are inferred from the claim text.