# US 12,759,083 B2 · Laser treatment method

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- Number: US 12,759,083 B2
- Document ID: US12759083B2
- Status: Granted
- Kind: B2
- Application number: 17/126,681
- Filed: 2020-12-18
- Published: 2021-07-15
- Granted: 2026-10-13
- Earliest claimed: 2019-12-20
- Assignees: ADIGE S.p.A.
- Applicants: Adige S.P.A.
- Inventors: Matteo Pacher; Mara Tanelli; Silvia Strada; Barbara Previtali; Sergio Matteo Savaresi; Maurizio Sbetti
- Web page: https://patentgrep.com/patent/US12759083B2

## CPC

- B23K 26/38: by boring or cutting
- B23K 26/032: {using optical means}
- G05B 13/042: {in which a parameter or coefficient is automatically adjusted to optimise the performance}
- G06T 7/0004: {Industrial image inspection}
- G06T 2207/10016: Video; Image sequence
- G06T 2207/20076: Probabilistic image processing
- G06T 2207/30136: Metal
- G06T 2207/30164: Workpiece; Machine component
- G06T 2207/30168: Image quality inspection
- 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
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

A laser treatment method of a metallic work piece comprising of at least a) directing a laser beam onto the work piece at a working zone of the working piece to execute a cutting and/or piercing; b) executing a relative movement between the laser beam and the work piece at a determined velocity; c) acquiring a plurality of acquired images of the working zone; d) determining a time course of at least one characteristic parameter from the acquired images; e) calculating at least one statistical parameter from the time course of the characteristic parameter; f) establishing a quality value from the statistical parameter; and g) controlling one or more process parameters, in particular at least an intensity, laser frequency, and/or position of the focus of the laser beam; the determined velocity; a gas jet; and/or a gas pressure of the gas jet, in function of the quality value.

## Claims

### Claim 1

A laser treatment method of a metallic work piece comprising at least the steps of:
a) directing a laser beam onto the work piece at a working zone of the working piece in order to execute a cutting and/or piercing;
b) executing a relative movement between the laser beam and the work piece at a determined velocity, the relative movement defining a direction of relative advancement, the direction of relative advancement being a direction of movement of the laser beam relative to the work piece;
c) acquiring a plurality of acquired images of the working zone;
d) determining, during which an analysis group determines respective time courses of a plurality of characteristic parameters from the acquired images
e) calculating, during which the analysis group calculates at least one statistical parameter from the respective time course of each characteristic parameter;
f) establishing, during which the analysis group establishes a quality value from the statistical parameters, and
g) controlling one or more process parameters, the one or more process parameters comprising at least one of: an intensity of the laser beam and/or a laser frequency of the laser beam and/or a position of the focus of the laser beam and/or the determined velocity and/or a gas jet and/or a gas pressure of the gas jet, in function of the quality value,
wherein as part of element e), determining respective probabilistic distributions from the respective time courses of the characteristic parameters over a defined time that is constant, and determining the respective statistical parameters from the respective probabilistic distributions, wherein, for determining each quality value, the analysis group analyzes a plurality of acquired images acquired in succession during the defined time, and successive pluralities of acquired images cover the defined time and partially overlap by at least one acquired image,
wherein during step d), a transformation sub-step is performed, during which each acquired image is transformed into a respective transformed image; the transformation step being a thresholding sub-phase during which each acquired image is segmented in order to obtain the respective transformed image corresponding to a binary image;
wherein during step d), each acquired transformed image is analyzed to determine the one or more characteristic parameters;
wherein each acquired transformed image comprises a high-intensity zone,
wherein each high-intensity zone is defined by the zones of the respective acquired image, which have intensities that are greater than or equal to a determined intensity threshold;
wherein each characteristic parameter is obtained from the respective high intensity zones of the respective acquired images and at least one characteristic parameter is, or is a function of, a width of the high-intensity zone and at least one other characteristic parameter is, or is a function of, a length of the high-intensity zone;
wherein the respective width of each high-intensity zone is defined by a maximal extension of the respective high-intensity zone in a direction perpendicular to the direction of relative advancement;
wherein each high-intensity zone comprises a main portion and one or more elongated portions extending from the main portion; and
wherein the length of each high-intensity zone is defined as a maximal extension of the high-intensity zone in the direction of relative advancement from a center of gravity of the high-intensity zone, the length corresponding to a maximal extension of an elongated portion of the high-intensity zone that is farthest from the center of gravity.

### Claim 2 (depends on 1)

The method according to claim 1, further comprising at least one h) repeat step during which at least the steps c)-f) are repeated one or more times.

### Claim 3 (depends on 1)

The method according to claim 1, wherein as part of element e), the statistical parameter is chosen from at least one of: a respective medium value, a respective variance, or a respective skewness of the probabilistic distribution.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the statistical parameter and the quality value characterize a presence and/or a formation and/or a quantity of dross.

### Claim 5 (depends on 1)

The method according to claim 1, further comprising the step of defining a desired quality value;
wherein during the step of controlling, the process parameter or the process parameters are controlled as a function of the quality value and the desired quality value.

### Claim 6 (depends on 5)

The method according to claim 5, wherein during the step g), the process parameter or the process parameters are controlled in a manner to obtain a quality value equal to the desired quality value.

### Claim 7 (depends on 1)

The method according to claim 1, wherein each acquired image is a heat image.

### Claim 8 (depends on 1)

The method according to claim 1, wherein during the step f), the quality value is obtained from the statistical parameter from a linear function or a non-linear function.

### Claim 9 (depends on 1)

The method according to claim 1, wherein during the step c), the acquired images are acquired at a rate of at least 1000 frames per second.

### Claim 10 (depends on 9)

The method according to claim 9, wherein during the step c), the acquired images are acquired at a rate of at least 1500 frames per second.

### Claim 11 (depends on 1)

The method according to claim 1, further comprising at least one h) repeat step during which at least the steps a)-f) are repeated one or more times.

### Claim 12 (depends on 1)

The laser treatment method according to claim 1, wherein as part of element c), the acquired images are acquired by a video camera, the video camera being disposed in a coaxial configuration with an optical axis along which the laser beam propagates.

### Claim 13 (depends on 1)

The laser treatment method of claim 1, wherein the direction of relative advancement being a movement of the laser beam relative to the work piece.

### Claim 14

A laser treatment machine configured to cut and/or pierce a work piece, the laser treatment machine comprising:
a control unit configured to control an actuation of the laser treatment machine;
an emission source of a laser beam operatively connected to the control unit and configured to emit the laser beam;
an optical group configured to control the laser beam; and
a movement device operatively connected to the control unit and configured to execute a relative movement between the laser beam and the work piece at a determined velocity, the laser treatment machine being configured at least to:
a) direct a laser beam onto the work piece at a working zone of the working piece in order to execute a cutting and/or piercing;
b) execute a relative movement between the laser beam and the work piece at a determined velocity, the relative movement defining a direction of relative advancement, the direction of relative advancement being a direction of movement of the laser beam relative to the work piece;
c) acquire a plurality of acquired images of the working zone;
d) determine, by an analysis group respective time courses of a plurality of characteristic parameters from the acquired images;
e) calculate, by the analysis group, at least one statistical parameter from the respective time course of each characteristic parameter;
f) establish, by the analysis group, a quality value from the statistical parameters; and
g) control one or more process parameters, the one or more process parameters comprising at least one of: an intensity of the laser beam and/or a laser frequency of the laser beam and/or a position of the focus of the laser beam and/or the determined velocity and/or a gas jet and/or a gas pressure of the gas jet, in function of the quality value,
wherein as part of element e), the analysis group determines respective probabilistic distributions from the respective time courses of the characteristic parameters over a defined time that is constant, and determines the respective statistical parameters from the respective probabilistic distributions, wherein for determining each quality value, the analysis group analyzes a plurality of acquired images acquired in succession during the defined time, and successive pluralities of acquired images cover the defined time and partially overlap by at least one acquired image,
wherein during step d), a transformation sub-step is performed, during which each acquired image is transformed into a respective transformed image; the transformation step being a thresholding sub-phase during which each acquired image is segmented in order to obtain the respective transformed image corresponding to a binary image;
wherein during step d), each acquired transformed image is analyzed to determine the one or more characteristic parameters;
wherein each acquired transformed image comprises a high-intensity zone,
wherein each high-intensity zone is defined by the zones of the respective acquired image, which have intensities that are greater than or equal to a determined intensity threshold;
wherein each characteristic parameter is obtained from the respective high intensity zones of the respective acquired images and at least one characteristic parameter is, or is a function of, a width of the high-intensity zone and at least one other characteristic parameter is, or is a function of, a length of the high-intensity zone;
wherein the respective width of each high-intensity zone is defined by a maximal extension of the respective high-intensity zone in a direction perpendicular to the direction of relative advancement;
wherein each high-intensity zone comprises a main portion and one or more elongated portions extending from the main portion; and
wherein the length of each high-intensity zone is defined as a maximal extension of the high-intensity zone in the direction of relative advancement from a center of gravity of the high-intensity zone, the length corresponding to a maximal extension of an elongated portion of the high-intensity zone that is farthest from the center of gravity.

### Claim 15 (depends on 14)

The laser treatment machine of claim 14, wherein the laser treatment machine is further configured such that at least the elements c)-f) are repeated one or more times.

### Claim 16 (depends on 14)

The laser treatment machine of claim 14, wherein the laser treatment machine is further configured such that at least the elements a)-f) are repeated one or more times.

### Claim 17 (depends on 14)

The laser treatment machine of claim 14, wherein the laser treatment machine is further configured such that in element e), the statistical parameter is chosen from at least one of: a respective medium value, a respective variance, or a respective skewness of the probabilistic distribution.

### Claim 18 (depends on 14)

The laser treatment machine of claim 14, wherein the direction of relative advancement being a movement of the laser beam relative to the work piece.

### Claim 19

A laser treatment method of a metallic work piece comprising at least the steps of:
a) directing a laser beam onto the work piece at a working zone of the work piece in order to execute a cutting and/or piercing;
b) executing a relative movement between the laser beam and the work piece, the relative movement defining a direction of relative advancement, the direction of relative advancement being a direction of movement of the laser beam relative to the work piece;
c) acquiring a plurality of acquired images of the working zone;
d) transforming each acquired image into a respective transformed image by thresholding each acquired image to obtain the respective transformed image corresponding to a binary image;
e) analyzing each transformed image to determine characteristic parameters comprising a width and a length of a high-intensity zone in the transformed image, the high-intensity zone being defined by zones of the respective acquired image having intensities greater than or equal to a determined intensity threshold, the high-intensity zone comprising a main portion and one or more elongated portions extending from the main portion, the width being defined as a maximal extension of the high-intensity zone in a direction perpendicular to the direction of relative advancement, and the length being defined as a maximal extension of the high-intensity zone in the direction of relative advancement from a center of gravity of the high-intensity zone, the length corresponding to a maximal extension of an elongated portion of the high-intensity zone that is farthest from the center of gravity;
f) determining respective time courses of the characteristic parameters from the plurality of acquired images;
g) calculating at least one statistical parameter from the respective time course of each characteristic parameter;
h) establishing a quality value from the at least one statistical parameter; and
i) controlling one or more process parameters in function of the quality value.