# US 10,502,550 B2 · Method of non-destructive testing a cutting insert to determine coating thickness

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- Number: US 10,502,550 B2
- Document ID: US10502550B2
- Status: Granted
- Kind: B2
- Application number: 15/386,295
- Filed: 2016-12-21
- Published: 2018-06-21
- Granted: 2019-12-10
- Earliest claimed: 2016-12-21
- Assignees: Kennametal Inc.
- Applicants: Kennametal Inc.
- Inventors: Naveen Kumar Kondameedi; Christoph Gey
- Web page: https://patentgrep.com/patent/US10502550B2

## CPC

- G01B 11/0616: {of coating}
- B23B 27/14: Cutting tools of which the bits or tips {or cutting inserts} are of special material
- B23B 2228/105: with specified thickness
- B23K 2101/35: {Surface treated articles}
- B23K 2103/166: {Multilayered materials}
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- B23B: TURNING; BORING (arrangements for copying or controlling B23Q)
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM

## Abstract

A method for non-destructive testing a cutting insert to determine coating thickness id disclosed. The method includes the steps of using a source of electromagnetic energy to ablate a surface of the cutting insert to non-destructively form a geometric feature and expose the substrate and each layer of the coating; and measuring the thickness of each layer of the coating. In one example, the geometric feature is a groove with a generally trapezoidal shape. In other examples, the groove can have a U-shape, V-shape, and the like. The thickness of each layer of the coating is determined using focus variation, contrast detection, confocal microscopy, an interferometric microscopy, an imaging interferometric microscopy, or similar technique.

## Claims

### Claim 1

A method for non-destructive testing of a cutting insert to maintain performance of the insert after the non-destructive testing, the cutting insert comprising a substrate and one or more layers of coating, the method comprising:
ablating the substrate and the one or more layers of coating of the cutting insert by using a source of electromagnetic energy, thereby forming a geometric feature having a depressed region in the surface of the cutting insert, the depressed region exposing each layer of the one or more layers of coating; and
measuring a thickness of each layer of the one or more layers of the coating at the depressed region.

### Claim 2 (depends on 1)

The method of claim 1, wherein the source of electromagnetic energy comprises a picosecond laser or a femtosecond laser.

### Claim 3 (depends on 2)

The method of claim 2, wherein the femtosecond laser operates at a wavelength of 1030 nm, a power of 50 W, a frequency in a range between 200 kHz and 800 kHz, and a pulse length of 900 fs.

### Claim 4 (depends on 1)

The method of claim 1, wherein the geometric feature is in the form of a groove, furrow, channel, or cavity.

### Claim 5 (depends on 1)

The method of claim 1, wherein the depressed region has a trapezoidal shape.

### Claim 6 (depends on 1)

The method of claim 1, wherein the depressed region has a V-shape.

### Claim 7 (depends on 1)

The method of claim 1, wherein the depressed region is formed in 7 seconds or less.

### Claim 8 (depends on 1)

The method of claim 1, wherein a depth of the depressed region is between 5 μm and 10 μm larger than a thickness of the coating being measure.

### Claim 9 (depends on 1)

The method of claim 1, wherein a depth of the depressed region is between 50 μm and 75 μm.

### Claim 10 (depends on 1)

The method of claim 1, wherein the thickness of each layer is measured using one of a focus variation technique, a contrast detection technique, a confocal microscopy technique, an interferometric microscopy technique and an imaging interferometric microscopy technique.

### Claim 11

A method for non-destructive testing of a cutting insert to maintain performance of the insert after the non-destructive testing, the cutting insert comprising a substrate and one or more layers of coating, the method comprising:
ablating the substrate and the one or more layers of coating of the cutting insert by using a source of electromagnetic energy, thereby forming a geometric feature having a depressed region in the surface of the cutting insert, the depressed region having a bottom defined by an exposed portion of the substrate, the depressed region exposing a cross section of each layer of the one or more layers of coating; and
measuring a thickness of the exposed cross section of each layer of the one or more layers of coating at the depressed region.

### Claim 12 (depends on 11)

The method of claim 11, wherein the geometric feature is in the form of a groove, furrow, channel, or cavity.

### Claim 13 (depends on 11)

The method of claim 11, wherein the depressed region has a trapezoidal shape.

### Claim 14 (depends on 11)

The method of claim 11, wherein the depressed region has a V-shape.

### Claim 15 (depends on 11)

The method of claim 11, wherein the depressed region is formed in 7 seconds or less.

### Claim 16 (depends on 11)

The method of claim 11, wherein a depth of the depressed region is between 5 μm and 10 μm larger than a thickness of the coating being measure.

### Claim 17 (depends on 11)

The method of claim 11, wherein a depth of the depressed region is between 50 μm and 75 μm.

### Claim 18

A method for non-destructive testing of a cutting insert to maintain performance of the insert after the non-destructive testing, the cutting insert comprising a substrate and a first coating layer, the method comprising:
ablating the first coating layer of the cutting insert by using a source of electromagnetic energy, thereby forming a geometric feature having a depressed region in the surface of the cutting insert, the depressed region exposing a cross section of the first coating layer; and
measuring a thickness of the exposed cross section of the first coating layer at the depressed region.

### Claim 19 (depends on 18)

The method of claim 18, wherein the geometric feature is in the form of a groove, furrow, channel, or cavity.

### Claim 20 (depends on 18)

The method of claim 18, wherein the cutting insert further comprises a second coating layer.