Method for producing an axially extending tool tip and tool tip

Patent metadata

Field	Value
Publication number	US-10144104-B2
Application number	US-201414768362-A
Country	US
Kind code	B2
Filing date	Feb 14, 2014
Priority date	Feb 18, 2013
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

In order, in a drill tip (2) which is provided particularly for a modular drilling tool, to generate a ridge (18) with supporting chamfers (26, 28) in a simple way, a non-round grinding method is provided, in which, proceeding from a starting rotary position (30) which corresponds to a cutting corner position, the radius is first reduced and is subsequently increased again to form the supporting chamfer (28). There is therefore no need for a separate grinding step to form the supporting chamfers (26, 28). The supporting chamfers (26, 28) preferably extend parallel to the longitudinal mid-axis (22) in the axial direction (24) and intersect coiled chucking grooves (26).

First claim

The invention claimed is:

1. A method for producing a tool tip which extends along a longitudinal mid-axis in the axial direction and which has a body with a plurality of chucking grooves introduced therein and with a respective ridge extending between adjacent chucking grooves, the method comprising:
in a first grinding step, grinding a blank to generate a non-round cross-sectional geometry, such that at each ridge, proceeding from a starting rotary position corresponding to a cutting corner adjacent a first chucking groove, a radius of the blank decreases to form a guide chamfer, then becomes rectilinear, then increases again to form a supporting chamfer, and then decreases again from the supporting chamfer until reaching a second chucking groove,
wherein the starting rotary position of the blank after the first grinding step has a nominal radius (R) defined as a radial distance from the longitudinal mid-axis to the starting rotary position;
wherein the supporting chamfer has a chamfer radius (r 4 ) defined as a radial distance from the longitudinal mid-axis to the supporting chamfer; and
wherein the chamfer radius (r 4 ) is smaller than the nominal radius (R).

2. The method according to claim 1 , wherein the chucking grooves are coiled; and wherein the supporting chamfer generated by grinding continues in the axial direction with lower twist than that of the chucking grooves.

3. The method according to claim 1 , wherein, to generate the non-round cross-sectional geometry, the blank is rotated about the longitudinal mid-axis and the grinding wheel is fed perpendicularly to the axial direction in relation to the blank according to a desired cross-sectional contour, so that, during a revolution of the blank, a distance between the grinding wheel and the blank varies according to the desired cross-sectional contour.

4. The method according to claim 1 , wherein, in a second grinding step, the chucking grooves are ground; and wherein the first and the second grinding steps are used exclusively to form the chucking grooves and the first and second supporting chamfers on the respective ridge.

5. The method according to claim 1 , wherein the second chamfer radius (r 4 ) at the supporting chamfer is about 0.01 to 0.02 mm smaller than the nominal radius (R) at the cutting corner position.

6. The method according to claim 1 , wherein the basic body is designed to diminish conically in the axial direction.

7. The method according to claim 1 , wherein the tool tip is an exchangeable tool tip for a modular drilling tool.

8. A tool tip produced by means of a method according to claim 1 .

9. The tool tip according to claim 8 , wherein the first and second supporting chamfers runs axially parallel to the axial direction.

10. The tool tip according to claim 9 , wherein the non-round cross-sectional geometry is continued axially parallel in the axial direction, so that the coiling of the chucking grooves reduces the distance of a cant delimiting the chucking groove from the longitudinal mid-axis, starting from a cutting corner.

11. The method of claim 2 , wherein the non-round cross-sectional geometry generated in the first grinding step is continued in the axial direction without twist.

12. The method of claim 1 , wherein the guide chamfer and the supporting chamfer are formed at an angle of about 70 degrees apart from each other.

Assignees

• Kennametal Inc

Inventors

• Jaeger Horst Manfred

Classifications

• B23B51/02

  Twist drills · CPC title

• B24B19/04 Primary

  for fluting drill shanks · CPC title

• B23B2251/446

  Drills with variable margins · CPC title