Laser treatment method

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.

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.