Method for comparing laser processing systems and method for monitoring a laser processing process and associated laser processing system

1 . A method for comparing a plurality of laser machining systems of a same type, wherein each of the plurality of laser machining systems comprises a laser machining head and a sensor module having at least one photodiode for detecting process radiation, said method comprising:

detecting radiation emitted from a light source by said photodiode and generating a corresponding intensity signal, wherein the radiation is guided from said light source to said photodiode by at least one optical element in said laser machining head and/or by at least one optical element of said sensor module;

aligning said laser machining head and said light source with one another so that the intensity signal assumes a maximum value;

comparing the maximum value of the intensity signal with at least one predetermined reference value; and

determining a scaling factor based on the comparison of the maximum value of the intensity signal and the at least one predetermined reference value,

wherein said light source is a stabilized and/or adjustable and/or controllable light source,

whereby the plurality of laser machining systems of the same type are inspected independently of laser machining processes and the laser machining processes carried out by the plurality of laser machining systems of the same type are monitored using the scaling factor.

2 . The method according to claim 1 , wherein a beam path of the detected radiation, at least in sections, overlaps and/or is coaxial with a beam path of a machining laser beam in said laser machining head.

3 . The method according to claim 1 , wherein said light source is or comprises at least one of: an electric light source, a halogen lamp, a light-emitting diode, a broadband light source, and a light source with an emission spectrum between 350 nm and 2000 nm.

4 . The method according to claim 1 , wherein the step of detecting radiation comprises detecting a radiation intensity of the radiation by the at least one photodiode in a predetermined wavelength range and/or at a predetermined wavelength.

5 . The method according to claim 4 , wherein the predetermined wavelength range is or comprises one of the following wavelength ranges: a visible wavelength range, a near-infrared (NIR) wavelength range, an infrared wavelength range, a wavelength range of thermal radiation, a wavelength range of plasma radiation, wavelengths between 350 nm and 780 nm, wavelengths between 780 nm and 3 μm, wavelengths greater than 1 μm, and/or

wherein the predetermined wavelength is a wavelength of a machining laser beam of the laser machining system and/or is 1064 nm.

6 . The method according to claim 1 , wherein the step of detecting radiation comprises:

detecting radiation by a first photodiode in a visible wavelength range and generating a first intensity signal based on the detected radiation; and/or

detecting radiation by a second photodiode at a wavelength of a machining laser beam of said laser machining system and generating a second intensity signal based on the detected radiation; and/or

detecting radiation by a third photodiode in an infrared wavelength range and generating a third intensity signal based on the detected radiation.

7 . The method according to claim 1 , wherein said optical element is or comprises one of the following: a transmissive element, a reflective element, a protective glass, a beam splitter, a mirror, a lens, a lens group, a lens pack, a focusing lens, a focusing optics, a collimating optics, a collimating lens, and a deflecting optics.

8 . The method according to claim 1 , wherein:

the method is for comparison of beam guidance of a plurality of laser machining heads of the plurality of laser machining systems of identical construction, and all steps are carried out with at least two laser machining heads of identical construction and with the same sensor module and the same light source; and/or

the method is for comparison of detection of a plurality of sensor modules of the same construction, and all steps are carried out with the same laser machining head and the same light source and with at least two sensor modules of the same construction; and/or

the method is for comparison of properties of a laser machining system at different points in time, and all steps are repeated with the same laser machining head, with the same sensor module and the same light source with a predetermined time interval.

9 . The method according to claim 1 , wherein the light source is fixedly installed, and/or wherein aligning said laser machining head and said light source with each other is carried out by moving said laser machining head.

10 . The method according to claim 1 , wherein the step of comparing the intensity signal with the at least one predetermined reference value comprises:

comparing a mean value and/or a maximum value of the intensity signal with a predetermined reference value.

11 . The method according to claim 10 , wherein, based on a mean value of the intensity signal for a specified laser machining head and a specified photodiode and based on the predetermined reference value, the scaling factor for this specified laser machining head and this specified photodiode is determined.

12 . A method for operating a laser machining system, wherein the laser machining system comprises a laser machining head and a sensor module having at least one photodiode for detecting process radiation, said method comprising:

detecting radiation emitted from a light source by said photodiode and generating a corresponding intensity signal, wherein the radiation is guided from said light source to said photodiode by at least one optical element in said laser machining head and/or by at least one optical element of said sensor module, wherein the radiation emitted from the light source is not reflected from a workpiece before being detected by said photodiode;

aligning said laser machining head and said light source with one another so that the intensity signal assumes a maximum value;

comparing the maximum value of the intensity signal with at least one predetermined reference value; and

determining a scaling factor based on the comparison of the maximum value of the intensity signal and the at least one predetermined reference value,

wherein said light source is a stabilized and/or adjustable and/or controllable light source,

whereby the laser machining system is inspected independently of laser machining process and the laser machining process carried out by the laser machining system is monitored using the scaling factor.

13 . A method for comparing at least two laser machining systems, wherein each of the laser machining systems comprises a laser machining head and a sensor module having at least one photodiode for detecting process radiation, said method comprising the following steps performed by a first laser machining system:

detecting radiation emitted from a light source by said photodiode and generating a corresponding intensity signal, wherein the radiation is guided from said light source to said photodiode by at least one optical element in said laser machining head and/or by at least one optical element of said sensor module;

aligning said laser machining head and said light source with one another so that the intensity signal assumes a maximum value; and

comparing the maximum value of the intensity signal with at least one predetermined reference value,

wherein said method further comprises the following steps performed by a second laser machining system:

detecting radiation emitted from the light source by said photodiode and generating a corresponding intensity signal, wherein the radiation is guided from said light source to said photodiode by at least one optical element in said laser machining head and/or by at least one optical element of said sensor module;

aligning said laser machining head and said light source with one another so that the intensity signal assumes a maximum value; and

comparing the maximum value of the intensity signal with the predetermined reference value,

the method further comprises determining a scaling factor based on the comparison of the maximum value of the intensity signal and the at least one predetermined reference value for each of the laser machining systems,

wherein each light source is a stabilized and/or adjustable and/or controllable light source,

whereby the first and second laser machining systems are inspected independently of laser machining processes and the laser machining processes carried out by the first and second laser machining systems are monitored using the scaling factor of the first and second laser machining systems.