Laser processing system

Abstract

In this laser processing system, it is desired that of a focal point of monitor light is matched with a processing spot all the time, even when a focal point of a laser light is shifted to an optical-axis direction.　The laser processing system includes: a laser-light variable focal-point mechanism which can change a focal point of laser light by control information based on a tertiary space coordinate of a processing spot; a laser-light deflection mechanism that coaxially controls positions of the laser light and the monitor light; a sensor that receives the monitor light; a reflection portion that guides the laser light to the laser-light deflection mechanism and guides the monitor light to the sensor; a monitor-light variable focal-point mechanism that can change a focal point of the monitor light by control information based on a tertiary space coordinate of the processing spot; and a control portion that controls a focal point of the laser light in the laser-light variable focal-point mechanism by control information based on a three-dimensional space coordinate of the processing spot and a defocus coordinate of the laser light and controls a focal point of the monitor light in the monitor-light variable focal-point mechanism by the control information based on at least the tertiary space coordinate of the processing spot.

Description

Laser Processing System

[0001] The present disclosure relates to laser processing systems.

[0002] Conventionally, there has been known a laser processing system that irradiates a processing portion of a workpiece with a laser beam to perform processing such as welding. In this laser processing system, a sensor image may be used to monitor the quality of the processing portion by the laser beam. When the processing portion by the laser beam is monitored using a sensor image, light emitted from the processing portion (hereinafter also referred to as "monitor light") is guided to the sensor via the same optical system as the optical system for irradiating the processing laser beam (see, for example, Patent Document 1).

[0003] JP 2012-148315 A

[0004] According to the above laser processing system, even if the focus of the laser light is moved to another processing location, the focus of the monitor light can always be aligned with the focus of the laser light. On the other hand, in laser welding, the processing location is heated by shifting the focus of the laser light in the optical axis direction. In conventional laser processing systems, when the focus of the laser light is shifted in the optical axis direction, the focus of the monitor light also shifts in the optical axis direction. When the focus of the monitor light shifts in the optical axis direction, the image of the sensor becomes a blurred image. This makes it difficult for the operator to properly monitor the processing location with the laser light.

[0005] Therefore, in a laser processing system, it is desirable to always keep the focus of the monitor light on the processing location even when the focus of the laser light is shifted in the optical axis direction.

[0006] a laser beam deflection mechanism that coaxially controls the position of the laser beam irradiated onto the processing location and the position of the monitor beam emitted from the processing location; a sensor that receives the monitor beam; a reflector that reflects the laser beam emitted from the laser beam variable focus mechanism and guides it to the laser beam deflection mechanism, and transmits the monitor beam emitted from the processing location and guides it to the sensor; a monitor beam variable focus mechanism that can change the focus of the monitor beam according to control information based on the three-dimensional spatial coordinates of the processing location; and a control unit that generates control information for controlling the focus of the laser beam in the laser beam variable focus mechanism, the positions of the laser beam and the monitor beam in the laser beam deflection mechanism, and the focus of the monitor beam in the monitor beam variable focus mechanism, wherein the control unit controls the focus of the laser beam in the laser beam variable focus mechanism according to control information based on the three-dimensional spatial coordinates of the processing location and the defocus coordinates of the laser beam, and controls the focus of the monitor beam in the monitor beam variable focus mechanism according to control information based on at least the three-dimensional spatial coordinates of the processing location.

[0007] Fig. 1 is a diagram illustrating the configuration of the laser processing system 1 and a first irradiation form of laser light. Fig. 2 is a diagram illustrating the focus of the three-dimensional spatial coordinates of the laser light (defocus coordinate H=0). Fig. 3 is a diagram illustrating the focus of the three-dimensional spatial coordinates of the laser light (defocus coordinate H≠0). Fig. 4 is a diagram illustrating the configuration of the laser processing system 1 and a second irradiation form of the laser light.

[0008] Hereinafter, an embodiment of a laser processing system according to the present disclosure will be described. The drawings attached to this specification are all schematic diagrams, and the shape, scale, aspect ratio, and the like of each part have been modified or exaggerated from the actual product in consideration of ease of understanding, etc.

[0009] (First embodiment) Fig. 1 is a diagram illustrating the configuration of a laser processing system 1 and a first irradiation form of laser light. Fig. 2 is a diagram illustrating the focus of the laser light in three-dimensional spatial coordinates (defocus coordinate H=0). Fig. 3 is a diagram illustrating the focus of the laser light in three-dimensional spatial coordinates (defocus coordinate H≠0). The first irradiation form of laser light refers to a form in which the focus of the laser light coincides with the processing location in the optical axis direction.

[0010] 1 is a system that performs processing such as welding by irradiating a workpiece (object to be processed) W placed on a movable stage (not shown) with laser light. Note that the application of the laser processing system 1 is not limited to the example in which a workpiece is placed on a movable stage, and can be changed as appropriate.

[0011] As shown in Fig. 1, the laser processing system 1 according to the embodiment includes a laser light source 10, a processing head 20, a sensor housing 30, and a control unit 40. The laser light source 10 is a device that oscillates a laser internally to generate laser light in response to a command from the control unit 40 (described later). Examples of the laser light source 10 include a fiber laser oscillator, a pulsed laser oscillator, a direct diode laser (DDL), and a CO ２ A laser oscillator, a solid-state laser (YAG laser) oscillator, or the like can be used. The laser light source 10 outputs the generated laser light to the processing head 20. In Fig. 1, the path of the laser light is indicated by a broken line, and the path of the monitor light is indicated by a solid line.

[0012] The processing head 20 is a device for irradiating the workpiece W with the laser light output from the laser light source 10 through an emission port (not shown). The processing head 20 is composed of a wobble head having a wobbling function (described later), a galvanometer scanner, and a polygon mirror. The processing head 20 is equipped with a laser light variable focus mechanism 21, a laser light deflection mechanism 22, a mirror 23, a lens 24, etc.

[0013] The laser beam variable focus mechanism 21 is a mechanism that can change the focus of the laser beam output from the laser light source 10. The laser beam variable focus mechanism 21 controls the focus of the laser beam based on control information commanded by the control unit 40 and based on the three-dimensional spatial coordinates X, Y, and Z of the processing location and the defocus coordinate H. Specifically, the laser beam variable focus mechanism 21 adjusts the position in the optical axis direction of a lens 26 (described below) for adjusting the focus of the laser beam based on control information related to the distance from a laser beam exit (not shown) to the processing location, so that the laser beam is focused at the position of the three-dimensional spatial coordinates X, Y, and Z of the processing location or at a position shifted from that position by the defocus coordinate H. In this embodiment, the "optical axis direction" refers to the direction along the optical axis of the laser beam and the optical axis of the monitor light.

[0014] A defocus coordinate (hereinafter also referred to as "defocus coordinate H") is a coordinate that indicates the amount by which the focus of the laser light is moved in the optical axis direction from a reference focus identified by three-dimensional spatial coordinates X, Y, and Z. As shown in FIGS. 2 and 3, the reference focus F0 of the laser light is expressed by three-dimensional spatial coordinates X, Y, and Z. In the example shown in FIG. 2, the value of the defocus coordinate H is 0, so the focus FA of the laser light coincides with the reference focus F0 (the processing location) in the optical axis direction. On the other hand, in the example shown in FIG. 3, the defocus coordinate H is not 0 (in this example, a negative value), so the focus FA of the laser light moves proximally from the reference focus F0 in the optical axis direction by the amount of the defocus coordinate H.

[0015] When the defocus coordinate H is set to a positive value, the focus FA of the laser beam moves distally in the optical axis direction relative to the reference focus F0 (not shown). On the other hand, when the defocus coordinate H is set to a negative value, the focus FA of the laser beam moves proximal to the reference focus F0 in the optical axis direction (upper side in the figure), as shown in FIG. 3. When the focus of the laser beam is moved distally or proximally to create a defocused state, the beam diameter of the laser beam increases, allowing the laser beam to be irradiated onto a wider area of ​​the workpiece. The defocused state of the laser beam is performed, for example, in operations that involve heating at a lower temperature than the heating temperature used during the actual welding, such as preheating before welding or slow cooling after welding.

[0016] As shown in FIG. 1 , the laser beam variable focus mechanism 21 includes lenses 25 and 26. The lenses 25 and 26 are optical components for adjusting the focus of the laser beam in the optical axis direction. The position of the lens 25 is fixed in the optical axis direction. The lens 26 (focusing lens) is supported so that its position in the optical axis direction is movable. The laser beam variable focus mechanism 21 includes a ball screw, a motor, etc. (not shown) as a mechanism for moving the position of the lens 26 in the optical axis direction. The ball screw is a linear motion mechanism that converts the rotational motion of the motor into linear motion. By controlling the position of the lens 26 in the optical axis direction with this linear motion mechanism, the focus of the laser beam can be moved in the optical axis direction.

[0017] The lens whose position is moved in the optical axis direction is not limited to lens 26, but may be lens 25, or both lenses 25 and 26 may be moved relatively. The mechanism for moving the focus of the laser light in the optical axis direction is not limited to a ball screw, but may be, for example, a linear motion mechanism using a linear guide, a mechanism for changing the focus by moving the position of a mirror (concave mirror), or a mechanism for changing the focus by changing the shape of a lens.

[0018] In a typical welding operation, the value of the defocus coordinate H is 0, and therefore the focus of the laser light is the reference focus F0. On the other hand, in an operation in which the laser light is defocused, the focus moves along the optical axis direction of the laser light according to the value of the defocus coordinate H. Therefore, the focus of the laser light is a point located distally or proximally away from the reference focus F0, which becomes the focus FA.

[0019] The laser beam deflection mechanism 22 is a device that controls the focal point of the laser beam A irradiated onto the processing location and the focal point of the monitor beam B emitted from the processing target coaxially. The laser beam deflection mechanism 22 controls mirrors 27 and 28 (described later) in response to commands from the control unit 40. Specifically, the laser beam deflection mechanism 22 adjusts the rotation angles of each mirror (described later) that scans the laser beam and the monitor beam, based on control information based on the two-dimensional spatial coordinates X and Y of the processing location, which is commanded from the control unit 40, so that the position of the laser beam A irradiated onto the processing location and the position of the monitor beam B emitted from the processing location are respectively at the two-dimensional spatial coordinates X and Y. Note that in FIG. 1, the laser beam A irradiated onto the processing target and the monitor beam B emitted from the processing target are shown shifted in position to make the relationship between them easier to understand, but the laser beam A and the monitor beam B are coaxial.

[0020] The laser beam deflection mechanism 22 includes mirrors 27 and 28. The mirrors 27 and 28 are optical components that reflect the laser beam and the monitor beam. The laser beam deflection mechanism 22 also includes a drive mechanism (not shown) that rotates the mirrors 27 and 28 around their respective rotation axes. The rotation angles of the mirrors 27 and 28 are controlled by the respective drive mechanisms, allowing the laser beam to scan a two-dimensional space on the workpiece W. When the laser beam deflection mechanism 22 irradiates the processing location of the workpiece W with laser beam, the monitor beam emitted from the processing location travels the same optical path as the laser beam and is emitted from the laser beam deflection mechanism 22 toward a sensor 31 (described below). In the processing head 20, the position of the beam outlet E (see FIGS. 2 and 3 ) of the laser beam deflection mechanism 22, which serves as the exit of the laser beam, is fixed.

[0021] The mirror (reflecting portion) 23 is an optical component that reflects the laser beam emitted from the laser beam deflection mechanism 22 and guides it to the laser beam variable focus mechanism 21, and transmits the monitor light emitted from the processing location. The mirror 23 is composed of a dichroic mirror that reflects light of a specific wavelength and transmits light of other wavelengths. The lens 24 is an optical component that focuses the laser beam reflected by the mirror 23 and the monitor light emitted from the laser beam deflection mechanism 22.

[0022] The sensor housing 30 is a device that guides monitor light emitted from the processed portion to the sensor 31. The sensor housing 30 includes the sensor 31, a monitor light variable focus mechanism 32, and a mirror 33.

[0023] The sensor 31 is a device that receives monitor light and generates an image of the processed portion of the workpiece W. The sensor 31 used when monitoring laser welding may be a camera, a photodiode (PD), or the like. The camera is used, for example, to receive infrared light emitted from the welded portion during laser welding and monitor the state of the keyhole and molten pool. The photodiode is used, for example, to receive infrared light emitted from the welded portion during laser welding and estimate the temperature of the welded portion from the radiated light. The photodiode is also used, for example, to receive visible light emitted from the welded portion during laser welding and observe the presence or absence of plasma light generated in the event of a poor weld.

[0024] The monitor light variable focus mechanism 32 is a mechanism that can change the focus of the monitor light. The monitor light variable focus mechanism 32 controls the focus of the monitor light based on control information based on the three-dimensional spatial coordinates X, Y, and Z of the processing location, which is commanded by the control unit 40. Specifically, the monitor light variable focus mechanism 32 adjusts the position in the optical axis direction of a lens 34 (described below) that adjusts the focus of the monitor light, based on control information related to the distance from the laser light exit E (see FIGS. 2 and 3 ) to the processing location, so that the monitor light is focused on the position of the three-dimensional spatial coordinates X, Y, and Z of the processing location.

[0025] As shown in FIG. 1 , the monitor light variable focus mechanism 32 includes a lens 34. The lens 34 (focus lens) is an optical component for adjusting the focus of the monitor light. The lens 34 is supported so that its position in the optical axis direction is movable. The monitor light variable focus mechanism 32 includes a ball screw, a motor, and the like (not shown) as mechanisms for moving the position of the lens 34 in the optical axis direction. The ball screw is a linear motion mechanism that converts the rotational motion of the motor into linear motion. By controlling the position of the lens 34 in the optical axis direction with this linear motion mechanism, the focus of the monitor light can be moved in the optical axis direction.

[0026] The mechanism for moving the focus of the monitor light in the optical axis direction is not limited to a ball screw, but may be, for example, a linear guide mechanism, a mechanism for changing the focus by moving the position of a mirror (concave mirror), or a mechanism for changing the focus by changing the shape of a lens.

[0027] The control information based on the three-dimensional spatial coordinates X, Y, and Z of the processing location, which is instructed by the control unit 40 to the monitor light variable-focus mechanism 32, is the same as the control information based on the three-dimensional spatial coordinates X, Y, and Z of the processing location, which is instructed by the control unit 40 to the laser light variable-focus mechanism 21. Therefore, in a first laser light irradiation mode (described below), the focus of the three-dimensional spatial coordinates of the monitor light coincides with the focus of the three-dimensional spatial coordinates of the laser light at the processing location. On the other hand, because the monitor light variable-focus mechanism 32 does not control the focus using the defocus coordinate H, the focus of the three-dimensional spatial coordinates of the monitor light also coincides with the processing location in a second laser light irradiation mode (described below). The mirror 33 is an optical member for directing the monitor light that has passed through the mirror (reflector) 23 into the monitor light variable-focus mechanism 32.

[0028] The control unit 40 controls the focus of the laser beam in the laser beam variable-focus mechanism 21, the positions of the laser beam and the monitor beam in the laser beam deflection mechanism 22, and the focus of the monitor beam in the monitor beam variable-focus mechanism 32. Specifically, the control unit 40 controls the position of the lens in the optical axis direction for adjusting the focus of the laser beam by sending control information based on the three-dimensional spatial coordinates X, Y, and Z and the defocus coordinate H of the processing location as a command to the laser beam variable-focus mechanism 21. The control unit 40 also controls the rotation angle of the mirror that scans the laser beam and the monitor beam in two-dimensional space by sending control information based on the two-dimensional spatial coordinates X and Y of the processing location as a command to the monitor beam variable-focus mechanism 32.

[0029] In addition to the above-mentioned control information, the commands transmitted from the control unit 40 to the laser beam variable focus mechanism 21, the laser beam deflection mechanism 22, and the monitor beam variable focus mechanism 32 may include speed commands instructing the operating speeds of the lenses, mirrors, etc. In the laser beam variable focus mechanism 21, the laser beam deflection mechanism 22, and the monitor beam variable focus mechanism 32, the operating speeds of the lenses, mirrors, etc. are set based on the speed commands from the control unit 40.

[0030] The control unit 40 is configured by a computer including, for example, memories such as ROM and RAM, a CPU, and a communication control unit. The control unit 40 executes various functions in cooperation with each piece of hardware by appropriately reading and executing an operating system (OS) and various application programs stored in an external memory. The control unit 40 may be configured by a CNC (Computer Numerical Controller), a PLC (Programmable Logic Controller), or the like, or may be connected to a higher-level computer that outputs machining conditions and the like in addition to machining programs.

[0031] Next, the first and second irradiation forms of the laser beam in the laser processing system 1 will be described with reference to Figures 1 to 3 and 4. Figure 4 is a diagram illustrating the configuration of the laser processing system 1 and the second irradiation form of the laser beam. The second irradiation form of the laser beam refers to a form in which the focus of the laser beam is shifted from the processing location in the optical axis direction.

[0032] In the first irradiation mode, the control unit 40 transmits control information based on the three-dimensional spatial coordinates X, Y, and Z of the processing location and the defocus coordinate H (H = 0) as a command to the laser beam variable-focus mechanism 21. In the first irradiation mode, because the value of the defocus coordinate H is 0, the laser beam variable-focus mechanism 21 does not perform control to move the focus of the laser beam from the reference focus F0 in the optical axis direction. In the first irradiation mode, the laser beam variable-focus mechanism 21 controls the focus of the laser beam to coincide with the three-dimensional spatial coordinates X, Y, and Z based on the control information commanded by the control unit 40.

[0033] In the first irradiation mode, the control unit 40 sends control information based on the two-dimensional spatial coordinates X, Y of the processing location as a command to the laser beam deflection mechanism 22. As a result, the laser beam deflection mechanism 22 controls the two-dimensional spatial position of the laser beam so that the focus of the laser beam coincides with the processing location. Also, in the first irradiation mode, the control unit 40 sends control information based on the three-dimensional spatial coordinates X, Y, Z of the processing location as a command to the monitor beam variable-focus mechanism 32. As a result, the monitor beam variable-focus mechanism 32 controls the focus of the monitor beam so that it coincides with the processing location.

[0034] 1, in the first irradiation mode, the focus FA of the laser beam A and the focus FB of the monitor beam B coincide with the reference focus F0 (the processing location). In the first irradiation mode, the focus of the monitor beam coincides with the focus of the laser beam, so the operator can monitor the quality of the processing location by the laser beam using a focused image.

[0035] In the second irradiation mode, the control unit 40 transmits control information based on the three-dimensional spatial coordinates X, Y, and Z of the processing location and the defocus coordinate H as a command to the laser beam variable-focus mechanism 21. Here, an example will be described in which the focus of the laser beam is moved proximally from the processing location. When the focus of the laser beam is moved proximally from the processing location, the defocus coordinate H becomes a negative value. In the second irradiation mode, the laser beam variable-focus mechanism 21 controls the focus of the laser beam in accordance with the command transmitted from the control unit 40 so that the focus of the laser beam is moved proximally from the position coinciding with the three-dimensional spatial coordinates X, Y, and Z by the amount of the defocus coordinate H (negative value).

[0036] In the second irradiation mode, the control unit 40 transmits the two-dimensional spatial coordinates X, Y of the processing location as a command to the laser beam deflection mechanism 22. As a result, the laser beam deflection mechanism 22 controls the two-dimensional spatial position of the laser beam so that the focus of the laser beam coincides with the processing location. Also, in the second irradiation mode, the control unit 40 transmits the three-dimensional spatial coordinates X, Y, Z of the processing location as a command to the monitor beam variable-focus mechanism 32. As a result, the monitor beam variable-focus mechanism 32 controls the position of the monitor beam in the optical axis direction so that the focus of the monitor beam coincides with the processing location.

[0037] As shown in Figure 4, in the second irradiation mode, the focus of the laser light moves proximally from the reference focus F0 (the processing location) by the amount of defocus coordinate H. Meanwhile, the focus of the monitor light coincides with the processing location. In the second irradiation mode, the focus of the monitor light coincides with the reference focus F0 regardless of where the focus of the laser light moves in the optical axis direction. Therefore, the sensor 31 can generate a focused image as an image of the processing location by the laser light, even while the focus of the laser light is shifted in the optical axis direction to heat the processing location.

[0038] As described above, according to the laser processing system 1 of the first embodiment, the focus of the monitor light can always be aligned with the processing location even when the focus of the laser light is shifted in the optical axis direction. Therefore, even while the operator is performing the work of heating the processing location by shifting the focus of the laser light in the optical axis direction, the operator can monitor the quality of the processing location by the laser light using the focused image.

[0039] Second Embodiment The laser light used for laser welding and the monitor light for monitoring the processing location have different wavelengths. For example, the wavelength of the laser light is 1070 nm, and the wavelengths of the monitor light are 400 to 600 nm, 800 to 900 nm, and 1300 to 1500 nm. As described above, when the wavelengths of the light used are different, the refractive index of the lens also differs. Therefore, even if the control unit 40 transmits the same control information, the focal points of the laser light and the monitor light may not coincide.

[0040] When ball screws are used as the linear motion mechanisms of the laser beam variable-focus mechanism 21 and the monitor beam variable-focus mechanism 32, the lens control information based on three-dimensional spatial coordinates is the motor rotation angle calculated by the following equation (1): Motor rotation angle = (target position × first conversion coefficient) + second conversion coefficient (1) Here, the target position is the focal position of the laser beam (X, Y, Z or X, Y, Z, H). The first conversion coefficient is a coefficient used to calculate the motor rotation angle required to move the lens to the target position. The first conversion coefficient differs depending on the lens specifications (type). The second conversion coefficient is a coefficient used to correct the lens installation position and the positions of the reference focus F0 and the focus FB.

[0041] When the specifications of the lens for adjusting the focus of the laser light and the specifications of the lens for adjusting the focus of the monitor light are different, the control unit 40 sets the first conversion coefficient according to the specifications of each lens. When the specifications of the lens for adjusting the focus of the laser light and the specifications of the lens for adjusting the focus of the monitor light are the same or have similar optical characteristics, the control unit 40 sets the value of the first conversion coefficient according to the specifications of the lens and also sets the value of the second conversion coefficient according to the wavelengths of the laser light and the monitor light.

[0042] According to the second embodiment, even when the wavelengths of the laser light and the monitor light are different, the focal points of the laser light and the monitor light can be aligned, and therefore, even when the wavelength of light used varies depending on the sensor specifications, the focus of the monitor light can be more appropriately adjusted.

[0043] Third Embodiment Laser welding may be performed using a technique called wobbling. Wobbling is a technique in which welding is performed while moving the focal position of a laser beam at high speed. When laser welding is performed using wobbling, the speed command is faster than usual, so the lens 26 in the laser beam variable focus mechanism 21 moves at high speed. On the other hand, in the monitor beam variable focus mechanism 32, there is no problem in monitoring the processing location even if the movement of the monitor beam does not follow the movement of the laser beam. Therefore, when the speed command exceeds a predetermined value, as in laser welding using wobbling, the speed command sent from the control unit 40 to the monitor beam variable focus mechanism 32 is set relatively smaller than the speed command sent to the laser beam deflection mechanism 22. This extends the life of the ball screw, which serves as a linear motion mechanism constituting the monitor beam variable focus mechanism 32, and enables more stable operation of the system.

[0044] (Modifications) Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. Furthermore, these embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these.

[0045] In the embodiment, an example has been described in which the focus of the monitor light in the monitor light variable-focus mechanism 32 is controlled by control information based on the three-dimensional spatial coordinates X, Y, and Z of the processing location, but the present invention is not limited to this. The focus of the monitor light in the monitor light variable-focus mechanism 32 may also be controlled by control information based on the three-dimensional spatial coordinates X, Y, and Z of the processing location and the defocus coordinate H.

[0046] In the embodiment, an example has been described in which the focus of the laser beam and the focus of the monitor beam are controlled coaxially in the laser beam deflection mechanism 22 using control information based on the two-dimensional spatial coordinates X, Y of the processing location, but the present invention is not limited to this. The focus of the laser beam and the focus of the monitor beam may also be controlled coaxially in the laser beam deflection mechanism 22 using control information based on the three-dimensional spatial coordinates X, Y, Z of the processing location.

[0047] The following supplementary notes are further disclosed regarding the above embodiment: (Supplementary Note 1) A laser beam variable focus mechanism (21) capable of changing the focus of laser beam output from a laser light source in accordance with control information based on three-dimensional spatial coordinates of a processing location, a laser beam deflection mechanism (22) coaxially controlling the position of the laser beam irradiated onto the processing location and the position of monitor beam emitted from the processing location, a sensor (31) for receiving the monitor beam, a reflecting unit (23) for reflecting the laser beam emitted from the laser beam variable focus mechanism and guiding it to the laser beam deflection mechanism, and transmitting the monitor beam emitted from the processing location and guiding it to the sensor, and a laser beam variable focus mechanism (21) capable of changing the focus of laser beam output from a laser light source in accordance with control information based on three-dimensional spatial coordinates of a processing location, a laser beam deflection mechanism (22) for coaxially controlling the position of the laser beam irradiated onto the processing location and the position of monitor beam emitted from the processing location, a sensor (31) for receiving the monitor beam, a reflecting unit (23) for reflecting the laser beam emitted from the laser beam variable focus mechanism and guiding it to the laser beam deflection mechanism, and transmitting the monitor beam emitted from the processing location and guiding it to the sensor, and a control unit (40) for controlling the focus of the laser beam in the laser beam variable focus mechanism, the positions of the laser beam and the monitor beam in the laser beam deflection mechanism, and the focus of the monitor beam in the monitor beam variable focus mechanism, wherein the control unit controls the focus of the laser beam in the laser beam variable focus mechanism using control information based on three-dimensional spatial coordinates of a processing location and defocus coordinates of the laser beam, and controls the focus of the monitor beam in the monitor beam variable focus mechanism using control information based on at least the three-dimensional spatial coordinates of the processing location. (Supplementary Note 2) The control unit (40) sets a conversion coefficient used to adjust the focus of the laser beam in controlling the laser beam variable focus mechanism (21) and a conversion coefficient used to control the focus of the monitor beam in controlling the monitor beam variable focus mechanism to different values. (Supplementary Note 3) When the speed command for the laser beam variable focus mechanism (21) is equal to or greater than a preset value, the control unit (40) sets the speed command for the monitor beam variable focus mechanism (32) to be relatively smaller than the speed command for the laser beam variable focus mechanism.

[0048] 1: Laser processing system, 10: Laser light source, 20: Processing head, 21: Laser beam variable focus mechanism, 22: Laser beam deflection mechanism, 23: Mirror (reflecting portion), 30: Sensor housing, 31: Sensor, 32: Monitor beam variable focus mechanism, 40: Control portion

Claims

1. A laser beam variable focus mechanism capable of changing the focus of laser beam output from a laser light source in accordance with control information based on three-dimensional spatial coordinates of a processing location; a laser beam deflection mechanism coaxially controlling the position of the laser beam irradiated to the processing location and the position of monitor beam emitted from the processing location; a sensor for receiving the monitor beam; a reflecting section for reflecting the laser beam emitted from the laser beam variable focus mechanism and guiding it to the laser beam deflection mechanism, and transmitting the monitor beam emitted from the processing location and guiding it to the sensor; a monitor beam variable focus mechanism capable of changing the focus of the monitor beam in accordance with control information based on three-dimensional spatial coordinates of the processing location; and a control section for generating control information for controlling the focus of the laser beam in the laser beam variable focus mechanism, the positions of the laser beam and the monitor beam in the laser beam deflection mechanism, and the focus of the monitor beam in the monitor beam variable focus mechanism, wherein the control section controls the focus of the laser beam in the laser beam variable focus mechanism in accordance with control information based on the three-dimensional spatial coordinates of the processing location and the defocus coordinates of the laser beam, A laser processing system that controls the focus of the monitor light in the monitor light variable focus mechanism based on control information based on at least three-dimensional spatial coordinates of a processing location.

2. The laser processing system of claim 1, wherein the control unit sets a conversion coefficient used to adjust the focus of the laser light in controlling the laser light variable focus mechanism and a conversion coefficient used to control the focus of the monitor light in controlling the monitor light variable focus mechanism to different values.

3. A laser processing system as described in claim 1 or 2, wherein the control unit makes the speed command for the monitor light variable focus mechanism relatively smaller than the speed command for the laser light variable focus mechanism when the speed command for the laser light variable focus mechanism is equal to or greater than a predetermined value.

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