# US 5,350,258 A · Ceramic cutting tool with chip control

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- Number: US 5,350,258 A
- Document ID: US5350258A
- Status: Granted
- Kind: A
- Application number: 07/897,226
- Filed: 1992-06-11
- Granted: 1994-09-27
- Earliest claimed: 1990-12-18
- Assignees: Kennametal Inc.
- Inventors: Craig W. Beeghly; Deepak P. Ahuja; Pankaj K. Mehrotra; Kenneth L. Niebauer
- Web page: https://patentgrep.com/patent/US5350258A

## CPC

- B23B 27/143: {characterised by having chip-breakers}
- B23B 2200/321: by chip breaking projections
- Y10T 82/10: Process of turning
- Y10T 407/235: with integral chip breaker, guide or deflector
- Y10T 407/245: comprising concave surface in cutting face of tool
- Y10T 407/27: comprising tool of specific chemical composition
- B23B: TURNING; BORING (arrangements for copying or controlling B23Q)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A ceramic cutting insert for high speed machining of materials is provided having an integral chip control surface thereon.

## Claims

### Claim 1

A ceramic cutting insert for high speed machining comprising:
a cutting edge,
a rake face with a chip control groove surface,
a flank face,
and wherein said cutting edge is formed at the juncture of said flank face and said rake face;
said ceramic insert comprising 0.5 to less than 5 volume percent silicon carbide whiskers, 5 to 15 volume percent zirconia, a residue of a magnesia addition added in an amount of zero to 3 volume percent, all dispersed in an alumina matrix;
and wherein said ceramic insert has a fracture toughness of at least 4.0 MPam.sup.1/2.

### Claim 2 (depends on 1)

The insert according to claim 1 wherein said flank face is in as molded condition.

### Claim 3 (depends on 2)

The insert according to claim 2 wherein said chip control groove surface is in an as molded condition.

### Claim 4 (depends on 1)

The insert according to claim 1 wherein said chip control groove surface is in an as molded condition.

### Claim 5 (depends on 1)

The insert according to claim 1 wherein said silicon carbide whiskers are present at a level of 0.5 to 2.5 volume percent and said zirconia is present at a level of 7.5 to 12.5 volume percent.

### Claim 6 (depends on 5)

The insert according to claim 5 wherein said magnesia addition is added in an amount of about 0.04 to 1 volume percent.

### Claim 7 (depends on 1)

The insert according to claim 1 wherein said fracture toughness is 4.0 MPam.sup.1/2 to less than 5.0 MPam.sup.1/2.

### Claim 8 (depends on 1)

The insert according to claim 1 further comprising means extending through the rake face and the thickness of the ceramic insert for receiving a locking means for holding said ceramic insert on a toolholder.