Laser processing device, laser processing method, and recording medium

Abstract

To provide a laser processing device capable of irradiating a processing object with an appropriate amount of laser beam.SOLUTION: A laser processing device 1 includes: a laser scanning part 17 for performing repetitive y scanning of a laser beam L within a repetitive scanning region R in a y direction, and x scanning of the laser beam L in an x direction crossing the y direction in combination with each other; and a laser control part 18 for causing a laser device 2 to intermittently emit the laser beam L during scanning. The x scanning alternately repeats advance and retreat of the laser beam L in the x direction, and each advance quantity is larger than each retreat quantity. The laser control part 18 allows the laser device 2 to temporarily stop emission of the laser beam L, in a range such that the advance and the retreat overlap each other in the x direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a laser processing apparatus and the like.

Background Art

[0002] Patent Document 1 discloses a laser welding apparatus that performs a linear welding process using laser light from a fiber laser apparatus. By reciprocating the laser light in small increments across the welding line, reliable welding across the welding line is made possible.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a composite laser scan that combines reciprocating vibration with line scanning as described above, the amount of laser light irradiated onto the welding object is increased compared to simple line scanning. Therefore, depending on the welding object, there is a risk that excessive melting may occur and appropriate welding may not be possible.

[0005] The present disclosure has been made in view of such circumstances, and an object thereof is to provide a laser processing apparatus and the like that can irradiate a processing object with an appropriate amount of laser light.

Means for Solving the Problems

[0006] To solve the above problems, a laser processing apparatus according to an aspect of the present disclosure includes a laser scanning unit that performs scanning by combining a first scan of laser light that repeatedly scans within a repeated scanning range along a first direction and a second scan of the laser light along a second direction that intersects the first direction, and a laser control unit that intermittently emits the laser light to a laser device during the scanning.

[0007] According to this aspect, since the laser light is intermittently emitted during the composite laser scanning combining the first scanning and the second scanning, it is possible to effectively prevent the workpiece from being irradiated with an excessive amount of laser light.

[0008] Another aspect of the present disclosure is a laser processing method. This method includes performing a scanning that combines a first scanning of laser light repeatedly within a repetitive scanning range along a first direction and a second scanning of the laser light along a second direction intersecting the first direction, and intermittently emitting the laser light to a laser device during the scanning.

[0009] Yet another aspect of the present disclosure is a storage medium. This storage medium stores a laser processing program that causes a computer to perform a scanning that combines a first scanning of laser light repeatedly within a repetitive scanning range along a first direction and a second scanning of the laser light along a second direction intersecting the first direction, and intermittently emit the laser light to a laser device during the scanning.

[0010] In addition, any combination of the above components, or those obtained by converting these expressions into methods, devices, systems, recording media, computer programs, etc., are also included in the present disclosure.

Advantages of the Invention

[0011] According to the present disclosure, an appropriate amount of laser light can be irradiated onto the workpiece.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0013] Hereinafter, embodiments for carrying out the present disclosure (hereinafter also referred to as embodiments) will be described in detail with reference to the drawings. In the description and / or the drawings, the same or equivalent components, members, processes, etc. are denoted by the same reference numerals and redundant descriptions are omitted. The scales and shapes of the respective parts shown are set for the sake of simplicity of the description and are not to be construed in a limited manner unless otherwise particularly mentioned. The embodiments are examples and do not limit the scope of the present disclosure in any way. All features presented in the embodiments and combinations thereof are not necessarily essential to the present disclosure. The embodiments are presented, for convenience, decomposed into components for each function and / or each function group for realizing it. However, one component in the embodiments may actually be realized by a combination of a plurality of components as separate entities, or a plurality of components in the embodiments may actually be realized by one component as an integral entity. Also, a plurality of embodiments and modification examples may be disclosed in parallel, but any components of each embodiment and / or each modification example may be combined in any manner as long as they do not inhibit each other's functions.

[0014] Figure 1 schematically shows the configuration of the laser processing apparatus 1 according to the first embodiment of the present disclosure. The laser processing apparatus 1 is an apparatus that irradiates a workpiece with laser light such as laser pulses oscillated or emitted by a laser device 2 such as a laser oscillator, and performs processing. Welding is exemplified as the processing. The laser processing apparatus 1 according to the example of the present embodiment is a laser welding apparatus that irradiates a workpiece with laser light to perform welding. In the example of the present embodiment where the laser processing apparatus 1 is a laser welding apparatus, different portions of one workpiece may be welded by laser light, or a plurality of different workpieces may be welded by laser light.

[0015] The laser device 2 is configured as a fiber laser device that emits laser light through an optical fiber 20. The laser light emitted by the laser device 2 is irradiated onto the workpiece while being scanned along the x-direction and the y-direction that intersect or are orthogonal to each other by a laser scanning unit 17 having a galvanometer scanner 14, which will be described later, as a main part. As will be described later, the laser control unit 18 integrally controls the laser device 2 and / or the laser scanning unit 17.

[0016] Figure 2 is a perspective view schematically showing the configuration of the laser processing apparatus 1 according to the second embodiment of the present disclosure. The laser processing apparatus 1 is an apparatus that irradiates a workpiece 3 with laser light such as laser pulses oscillated or emitted by a laser device 2 such as a laser oscillator, and performs processing. The type of processing is arbitrary and includes welding, cutting, drilling, annealing, etc. The laser processing apparatus 1 according to the example of the present embodiment is a laser welding apparatus that irradiates the workpiece 3 with laser light to perform welding. The workpiece 3 in the illustrated example is disk-shaped, but the shape of the workpiece 3 is arbitrary. In the example of the present embodiment where the laser processing apparatus 1 is a laser welding apparatus, different portions of one workpiece 3 may be welded by laser light, or a plurality of different workpieces 3 (not shown) may be welded by laser light.

[0017] The workpiece 3 fixedly placed on the table 31 can be driven integrally with the table 31 along the illustrated x-direction by a stage device 4 described later. Further, the laser beam emitted by the laser device 2 can be scanned along the y-direction intersecting or orthogonal to the x-direction by a laser scanning unit having a galvanometer scanner 14 described later as a main part. The laser beam scanned along the y-direction by the galvanometer scanner 14 is reflected by a mirror 16 described later and irradiated onto the workpiece 3 along the z-direction intersecting or orthogonal to the x-direction and the y-direction.

[0018] In the example of this embodiment, a three-dimensional orthogonal coordinate system with each of the XYZ axes orthogonal to each other as coordinate axes is conveniently used. The x-direction, which is the driving direction of the workpiece 3, is parallel to the X-direction, the y-direction, which is the scanning direction of the laser beam, is parallel to the Y-direction, and the z-direction, which is the incident direction of the laser beam on the workpiece 3, is parallel to the Z-direction. Hereinafter, the x-direction and the X-direction are also referred to as the longitudinal direction, the y-direction and the Y-direction are also referred to as the lateral direction, and the z-direction and the Z-direction are also referred to as the height direction.

[0019] The laser device 2 may be a CW (Continuous Wave) oscillation type laser oscillator that oscillates a laser beam as a temporally continuous continuous wave, or a pulse oscillation type laser oscillator that oscillates a laser beam (laser pulse) as a temporally discontinuous pulse. The laser device 2 according to the example of this embodiment is a pulse oscillation type laser oscillator.

[0020] The pulse oscillation type laser device 2 oscillates a laser pulse LP at a frequency of about 20 kHz, for example. Specifically, the frequency of the laser pulse LP oscillated by the laser device 2 is between 1 kHz and 50 kHz, preferably between 5 kHz and 20 kHz. However, the frequency of the laser pulse LP oscillated by the laser device 2 is arbitrary. As will be described later, in this embodiment, while the laser pulse LP is scanned by a laser scanning unit such as the galvanometer scanner 14, the laser pulse LP is intermittently emitted from the laser device 2. The frequency of such intermittent emission of the laser pulse LP is significantly lower than the oscillation frequency (about 20 kHz) of the laser pulse LP itself. Therefore, in the context of intermittent emission in this embodiment, the pulsed laser pulse LP can be treated substantially equivalently to continuous-wave laser light.

[0021] The laser device 2 may be configured as a fiber laser device that emits a laser pulse LP through an optical fiber. FIG. 3A schematically shows an optical fiber 20 which is a main part of the fiber laser device. The optical fiber 20 includes a core 201 at the center, a first cladding 202 provided around the core 201, and a second cladding 203 provided around the first cladding 202. The refractive index of the core 201 is higher than that of the first cladding 202, and the refractive index of the first cladding 202 is higher than that of the second cladding 203. That is, the refractive index of the optical fiber 20 is higher closer to the central part (core 201) and lower closer to the peripheral part (second cladding 203).

[0022] At one end of the optical fiber 20 (for example, the left end in FIG. 3A), excitation light EL emitted from a light-emitting element such as a laser diode is incident. This excitation light EL propagates inside the core 201 and the first cladding 202 while undergoing total reflection at the interface between the first cladding 202 and the second cladding 203. Each time the excitation light EL passes through the core 201, it excites rare earth elements such as Yb added to the core 201 to generate stimulated emission light that serves as the source of the laser pulse LP. The stimulated emission light generated in the core 201 in this way propagates inside the core 201 while undergoing total reflection at the interface between the core 201 and the first cladding 202. As will be described later, mirrors such as total reflection mirrors like FBG (Fiber Bragg Grating) or output mirrors are formed at both ends of the core 201. The stimulated emission light repeatedly reflected between these mirrors at both ends is amplified while traveling back and forth inside the core 201, thereby forming a laser pulse LP as coherent laser light. This laser pulse LP is emitted outside the optical fiber 20 from an output mirror formed at the other end of the core 201 (for example, the right end in FIG. 3A).

[0023] FIG. 3B schematically shows the configuration of a laser device 2 as a fiber laser device including an optical fiber 20 as shown in FIG. 3A. The laser device 2 includes an excitation light supply unit 21, a laser light generation unit 22, and a laser light supply unit 23. The excitation light supply unit 21 includes one or more light-emitting elements 211 such as laser diodes that emit light serving as the source of the excitation light EL, and an optical coupling unit 212 that couples the respective lights when a plurality of the light-emitting elements 211 are provided to form the excitation light EL. The excitation light supply unit 21 supplies the excitation light EL based on the light emitted by the light-emitting element 211 to the laser light generation unit 22.

[0024] The laser light generation unit 22 includes the aforementioned optical fiber 20 to which the excitation light EL is supplied from the input end (the left end in FIG. 3B), and the input mirror 221 and the output mirror 222 formed at both ends thereof. The input mirror 221 and the output mirror 222 are both formed at both ends of the core 201 as FBGs, for example. The reflectance of the input mirror 221 provided on the input side (the excitation light supply unit 21 side) is preferably higher than the reflectance of the output mirror 222 provided on the output side (the laser light supply unit 23 side). In particular, the input mirror 221 is preferably configured as a total reflection mirror that totally reflects the stimulated emission light inside the core 201 that is the source of the laser pulse LP to the output side. The output mirror 222 is a partial reflection mirror that reflects a part of the stimulated emission light inside the core 201 to the input side and outputs the rest to the laser light supply unit 23.

[0025] The laser light supply unit 23 includes an optical fiber 231 that guides the laser pulse LP generated by the laser light generation unit 22 to the output point OP of the laser device 2. Note that the output point of the laser light generation unit 22 may be set as the output point OP of the laser device 2, and in that case, it is not necessary to provide the laser light supply unit 23.

[0026] In FIG. 2, the laser pulse LP is emitted from the output point OP of the laser device 2 in the X direction. The laser processing device 1 or the laser scanning unit that guides this laser pulse LP to the processing object 3 to be irradiated includes a beam expander 11, a mirror 12, a beam shaping optical element 13, a galvanometer scanner 14, an fθ lens 15, and a mirror 16. In configuring the laser scanning unit that is responsible for scanning the laser pulse LP in the y direction (and / or the x direction), a scanning mechanism such as the galvanometer scanner 14 is essential, but the other components 11 to 13, 15 to 16 may be omitted as necessary.

[0027] All of the laser processing apparatus 1 or the beam expander 11, mirror 12, beam shaping optical element 13, galvanometer scanner 14, fθ lens 15, and mirror 16 that constitute the laser scanning unit are preferably integrally accommodated in a single housing (not shown). In this case, the output end of the optical fiber 20 or 231 that constitutes the output point OP of the laser device 2 may be directly connected to the input end (for example, provided immediately before the beam expander 11) in the housing.

[0028] The beam expander 11 adjusts the laser pulse LP emitted from the output point OP of the laser device 2 to a predetermined size or diameter. For example, when the cross-section of the laser pulse LP emitted from the output point OP of the laser device 2 is a substantially circular shape with a diameter D0, the beam expander 11 converts (typically, enlarges) the cross-section of the laser pulse LP into a substantially circular shape with a predetermined diameter D1. The beam expander 11 is composed of a plurality of lenses 111, 112, 113. Typically, the lens 111 is a convex lens, the lens 112 is a concave lens, and the lens 113 is a convex lens. However, the number and type of lenses and other optical elements that constitute the beam expander 11 are arbitrary as long as the intended action and / or effect of adjusting the size of the laser pulse LP can be obtained. For example, the beam expander 11 may be composed of two or more convex lenses and one or more concave lenses arranged in any order, or may be composed of only three or more convex lenses.

[0029] The mirror 12 reflects the laser pulse LP whose size has been adjusted by the beam expander 11 and changes its traveling direction from the X direction to the Y direction.

[0030] The beam shaping optical element 13 shapes the laser pulse LP whose size has been adjusted by the beam expander 11, and adjusts its shape and / or intensity distribution. For example, the cross section of the laser pulse LP whose size has been adjusted by the beam expander 11 has a substantially circular shape and an intensity distribution following a Gaussian distribution or a normal distribution, but may be shaped into a substantially rectangular shape with a substantially uniform intensity distribution by the beam shaping optical element 13. Such a beam shaping optical element 13 is constituted by, for example, a diffractive optical element (DOE: Diffractive Optical Element).

[0031] The galvanometer scanner 14 scans the laser pulse LP shaped by the beam shaping optical element 13 along the y direction (Y direction). The galvanometer scanner 14 includes a galvanometer mirror 141 that reflects the incident laser pulse LP and directs it to a desired scanning position in the y direction, and a motor 142 that rotationally drives the galvanometer mirror 141 around the Z axis. By adjusting the rotational position or rotational angle of the galvanometer mirror 141 around the Z axis by the motor 142, the laser pulse LP incident on the galvanometer mirror 141 is reflected to an arbitrary position in the y direction.

[0032] Note that, instead of the galvanometer scanner 14, a polygon mirror scanner including a polygon mirror that can be rotationally driven, or a drivable optical element such as a MEMS (Micro Electro Mechanical Systems) mirror may be used to direct the incident laser pulse LP toward a desired scanning position in the y direction. Further, the scanning direction of the laser pulse LP by the laser scanning unit such as the galvanometer scanner 14 is not limited to the y direction (Y direction), and may be a direction intersecting or orthogonal to the y direction (Y direction) such as the x direction (X direction), or may be two directions of the x direction (X direction) and the y direction (Y direction). When the laser scanning unit such as the galvanometer scanner 14 can scan the laser pulse LP alone in the xy plane (in the XY plane), that is, on the surface of the object to be processed 3, the stage device 4 that drives the object to be processed 3 and the table 31 in the x direction (X direction) or the like may not be provided. In this case, a laser scanning unit according to the present disclosure that performs an xy scan combining an x scan of the laser pulse LP along the x direction and a y scan of the laser pulse LP along the y direction is configured by a single galvanometer scanner 14 or the like.

[0033] The fθ lens 15 focuses the laser pulse LP scanned in the y direction (Y direction) by the galvanometer scanner 14 onto the object to be processed 3 to be welded. The mirror 16 provided between the fθ lens 15 and the object to be processed 3 reflects the laser pulse LP in the X direction from the fθ lens 15 and irradiates the object to be processed 3 along the Z direction (z direction). The laser pulse LP focused onto the object to be processed 3 by the fθ lens 15 and the mirror 16 moves along the Y direction (and / or the X direction) on the surface of the object to be processed 3 by scanning in the y direction (and / or the x direction) by the galvanometer scanner 14. The size of the laser pulse LP focused onto the object to be processed 3 can be arbitrarily designed according to the welding purpose or the processing purpose. Further, the standard moving speed or scanning speed of the laser pulse LP in the X direction and / or the Y direction on the object to be processed 3 can also be arbitrarily designed according to the welding purpose or the processing purpose.

[0034] The stage device 4 is a driving device that relatively drives the object to be processed 3 and the table 31 along the x-direction (X-direction) with respect to the laser pulse LP. Similar to the aforementioned galvanometer scanner 14 that performs y-scanning of the laser pulse LP along the y-direction with respect to the object to be processed 3, the stage device 4 constitutes a laser scanning unit according to the present disclosure that performs x-scanning of the laser pulse LP along the x-direction with respect to the object to be processed 3. By this stage device 4, the laser pulse LP relatively moves along the X-direction on the surface of the object to be processed 3.

[0035] As described above, by combining the y-direction scanning of the laser pulse LP by the galvanometer scanner 14 as the laser scanning unit in the y-direction and the x-direction scanning of the object to be processed 3 by the stage device 4 as the laser scanning unit in the x-direction, the laser pulse LP can be scanned in the xy-plane (XY-plane), that is, on the surface of the object to be processed 3. Note that the scanning direction or driving direction of the object to be processed 3 by the stage device 4 is not limited to the x-direction (X-direction), and may be a direction that intersects or is orthogonal to the x-direction (X-direction), such as the y-direction (Y-direction), or may be two directions of the x-direction (X-direction) and the y-direction (Y-direction). In the latter case, when the stage device 4 can relatively drive the object to be processed 3 with respect to the laser pulse LP in the xy-plane (XY-plane) alone, the galvanometer scanner 14 that scans the laser pulse LP in the y-direction (Y-direction) etc. may not be provided. In this case, a laser scanning unit according to the present disclosure that performs xy-scanning by combining the x-scanning of the laser pulse LP along the x-direction and the y-scanning of the laser pulse LP along the y-direction is constituted by the single stage device 4.

[0036] FIG. 4 is a schematic functional block diagram of a laser processing apparatus 1 as a laser welding apparatus for welding two workpieces 3A and 3B with a laser beam L such as a laser pulse LP. The laser processing apparatus 1 includes an xy two-dimensional laser scanning unit 17 constituted by the aforementioned galvanometer scanner 14 and / or stage apparatus 4, and a laser control unit 18 that integrally controls the laser apparatus 2 and / or the laser scanning unit 17. As long as the laser processing apparatus 1 can achieve at least a part of the operations and / or effects described below, a part of these functional blocks may be omitted. The laser control unit 18 may be realized by the cooperation of hardware resources such as a central processing unit, memory, input device, output device, and peripheral devices connected to a computer, and software executed using these resources. Regardless of the type and installation location of the computer, each of the above functional blocks may be realized by the hardware resources of a single computer, or may be realized by combining the hardware resources distributed among a plurality of computers.

[0037] In the example of this figure, the optical fiber 20 or 231 of the laser apparatus 2 as a fiber laser apparatus is directly connected to the laser scanning unit 17 having the galvanometer scanner 14 as a main part. The laser beam L output from the laser apparatus 2 is directly provided to the laser scanning unit 17 through the optical fiber 20 or 231. The laser scanning unit 17 scans the laser beam L input from the optical fiber 20 or 231 along two directions in the x direction and the y direction across the two workpieces 3A and 3B under the control of the laser control unit 18.

[0038] The two objects to be processed 3A and 3B have a gap G along the y direction as the first direction. This gap G extends along the x direction as the second direction. In order to close such a long gap G in the x direction by welding, the laser scanning unit 17 sequentially irradiates the laser beam L over a welding region W that is long in the x direction and includes the gap G. As will be described later, the overall scanning direction of the laser beam L is the x direction as the second direction in which the gap G and the welding region W extend, but fine or small y scans in the y direction as the first direction straddling the gap G are also combined. In the example of FIG. 4, the x direction and the y direction as the scanning directions by the laser scanning unit 17 are conveniently made to coincide with the second direction and the first direction, which are the long and short directions of the gap G, respectively. However, the scanning direction by the laser scanning unit 17 and the direction of the gap G do not have to coincide.

[0039] As will be described later, the laser scanning unit 17 performs two-dimensional scanning by combining the y scan as the first scan of the laser beam L within the repetitive scanning range R along the y direction as the first direction and the x scan as the second scan of the laser beam L along the x direction as the second direction. The laser control unit 18 intermittently emits the laser beam L to the laser device 2 during the scanning by the laser scanning unit 17.

[0040] FIG. 5 schematically shows a plurality of embodiments of the irradiation locus of the laser beam L by the laser scanning unit 17 and the laser control unit 18. FIG. 5A shows a comparative example in which the intermittent emission control of the laser beam L by the laser control unit 18 is not performed, and FIGS. 5B and 5C show embodiments in which the intermittent emission control of the laser beam L by the laser control unit 18 is performed. In these three examples, the scanning locus of the laser beam L by the laser scanning unit 17 is substantially the same, and only the presence or absence and the timing of the intermittent emission control of the laser beam L by the laser control unit 18 are different.

[0041] First, while referring to FIG. 5A, the scanning trajectory of the laser beam L common to FIGS. 5A to 5C will be described. Although detailed illustration is omitted, there is a gap G shown in FIG. 4 on the x-axis as the horizontal axis in this figure. One workpiece 3A exists above the x-axis, i.e., on the +y side, and the other workpiece 3B exists below the x-axis, i.e., on the -y side. The two-dimensional scanning of the laser beam L in such an xy plane is understood as being composed of a y-scan along the y-direction as the first direction and an x-scan along the x-direction as the second direction.

[0042] The y-scan as the first scan is a repetitive scan of the laser beam L within the repetitive scan range R along the y-direction. For example, the y-scan is a reciprocating scan of the laser beam L within the repetitive scan range R. In this case, the laser beam L reciprocates between both ends (the upper and lower ends in FIG. 5) of the repetitive scan range R. The scanning speed of the laser beam L along the y-direction at each y-direction position within the repetitive scan range R can be arbitrarily set according to the welding purposes of the workpieces 3A and 3B. For example, at the central position in the y-direction of the gap G, since the relatively small-diameter laser beam L derived from the fiber laser device (laser device 2) completely passes through the gap G and may not contribute to the welding of the workpieces 3A and 3B, it is preferable to maximize the speed of the y-scan at the central position. Note that the y-scan within the repetitive scan range R is not limited to a simple reciprocating scan, and it may be any scan or irradiation that repetitively or periodically scans or irradiates the laser beam L substantially over the entire repetitive scan range R as the y-direction range.

[0043] In order to appropriately weld the workpieces 3A and 3B, it is preferable that the gap G between the two is included within the repetitive scan range R in the y-direction. That is, the width of the repetitive scan range R (the vertical dimension in FIG. 5) is set to be at least larger than the width of the gap G. With such a repetitive scan range R, the laser beam L is appropriately irradiated across the gap G between the two workpieces 3A and 3B to be welded. When the gap G is long in the x-direction as shown in FIG. 4, the width of the repetitive scan range R (the vertical dimension in FIG. 4) is smaller than the total length of the gap G (the left-right dimension in FIG. 4).

[0044] The x-scan as the second scan is a scan that causes the laser beam L to travel along the x-direction (e.g., from left to right in FIG. 5). The x-scan may be a simple straight-forward scan of the laser beam L along the x-direction. In this case, the scanning trajectory of the laser beam L in the xy plane, unlike that shown in FIG. 5, becomes a simple zigzag shape or a meandering shape that is continuously repeated along the x-direction (not shown).

[0045] In the example of FIG. 5, the x-scan alternately repeats the forward movement F and the backward movement B of the laser beam L along the x-direction. Here, since the amount of each forward movement F is more than the amount of each backward movement B, the laser beam L gradually moves forward along the x-direction. Such an x-scan periodically or repeatedly repeats a predetermined forward period for moving the laser beam L forward (F) on the +x side and a predetermined backward period for moving the laser beam L backward (B) on the -x side. The sum of this forward period (F) and the backward period (B) is hereinafter referred to as the traveling period T. In the example of FIG. 5, this traveling period T coincides with the repetition period or the reciprocating period of the y-scan, which is a reciprocating scan within the repetitive scan range R. However, the traveling period T of the x-scan and the repetition period of the y-scan may be different from each other. In this case, the scanning trajectory of the laser beam L becomes an asymmetric shape instead of the symmetric shape as shown in FIG. 5.

[0046] By combining the periodic scans in the x-direction and the y-direction as described above, as shown in FIG. 5A, a regular or symmetric scanning trajectory of the laser beam L in a circular or elliptical shape that is continuous in the x-direction is formed. The envelope of this scanning trajectory may be interpreted as defining the outer periphery of the welding region W shown in FIG. 4. The width of such a welding region W (the dimension in the vertical direction in FIG. 4) coincides with the width of the repetitive scan range R of the y-scan.

[0047] In the composite laser scan that combines the line scan (x-scan) along the x-direction and the reciprocating vibration (y-scan) along the y-direction as shown in FIG. 5A, compared with a simple line scan, the irradiation amount of the laser beam L on the workpieces 3A and 3B increases. Therefore, depending on the material and thickness of the workpieces 3A and / or 3B, there is a risk that excessive melting may occur and appropriate welding may not be performed.

[0048] Therefore, in the present embodiment, a laser processing apparatus 1 is proposed that can irradiate the workpieces 3A and 3B with an appropriate amount of laser light L through the intermittent emission control of the laser light L by the laser control unit 18. The laser control unit 18 intermittently emits the laser light L to the laser device 2 during the laser scanning by the laser scanning unit 17 as shown in FIG. 5.

[0049] As shown in the example of FIG. 5B, the laser control unit 18 temporarily stops the emission of the laser light L to the laser device 2 in a range where the forward movement F and the backward movement B constituting the x-scanning overlap in the x-direction. In FIG. 5B, for example, the first forward movement F1 and the immediately subsequent backward movement B1 overlap in the x-direction, and the emission of the laser light L is temporarily stopped throughout all or part of the period of one of the backward movements B1. The scanning trajectory during which the emission of the laser light L is stopped in this way is schematically shown by a dotted line.

[0050] The laser control unit 18 alternately repeats a predetermined emission period (schematically represented as a solid-line scanning trajectory in FIG. 5) for causing the laser device 2 to emit the laser light L and a predetermined stop period (schematically represented as a dotted-line scanning trajectory in FIG. 5) for stopping the emission of the laser light L to the laser device 2. The sum of this emission period (solid line) and the stop period (dotted line) is hereinafter referred to as the intermittent emission cycle t. The ratio of the emission period and the stop period in each intermittent irradiation cycle t can be arbitrarily set according to the welding purpose of the workpieces 3A and 3B, but it is preferable that the emission period is equal to or less than the stop period. In the example of FIG. 5B, the emission period is approximately equal to the stop period.

[0051] In the example of FIG. 5B, the intermittent irradiation period t is approximately twice the traveling period T (the time required for one forward movement F and one backward movement B) in the x direction. That is, while approximately two traveling periods T elapse, the laser control unit 18 performs the intermittent emission control of the laser beam L once based on the intermittent irradiation period t. In this way, it is preferable that the traveling period T of the x scan (and / or the repetition period of the y scan) is shorter than the intermittent emission period t. In particular, if the intermittent emission period t is set to be approximately a natural number multiple (in the example of FIG. 5B, approximately twice) of the traveling period T of the x scan (and / or the repetition period of the y scan), an irradiation locus of the laser beam L with symmetry as shown in FIG. 5B can be realized. However, in the present disclosure, as shown in FIG. 6, the irradiation locus of the laser beam L may be asymmetric.

[0052] According to such an embodiment, since the laser beam L is intermittently emitted during the composite laser scan combining the x scan and the y scan, it is possible to effectively prevent the workpieces 3A and 3B from being irradiated with an excessive amount of the laser beam L. In this way, by irradiating an appropriate amount of the laser beam L, the workpieces 3A and 3B can be properly welded. Further, the welding quality can be stabilized by the symmetric irradiation locus of the laser beam L as shown in FIG. 5B. Note that various parameters such as the intermittent emission period t (and / or the emission period and / or stop period constituting the same), the traveling period T of the x scan (and / or the forward period and / or backward period constituting the same), the repetition period of the y scan, the average traveling speed of the x scan, and the width of the repetitive scan range R are preferably adaptively set according to the materials and thicknesses of the workpieces 3A and / or 3B to be welded.

[0053] In the example of FIG. 5C, the intermittent irradiation period t is approximately three times the traveling period T in the x direction (the time required for one forward movement F and one backward movement B). That is, while approximately three traveling periods T elapse, one intermittent emission control of the laser beam L based on the intermittent irradiation period t is performed by the laser control unit 18. Thus, it is preferable that the traveling period T of the x scan (and / or the repetition period of the y scan) is shorter than the intermittent emission period t. In particular, if the intermittent emission period t is set to approximately a natural number multiple (in the example of FIG. 5C, approximately three times) of the traveling period T of the x scan (and / or the repetition period of the y scan), an irradiation locus of the laser beam L with symmetry as shown in FIG. 5C can be realized.

[0054] In the examples of FIGS. 5B and 5C, when the irradiation locus of the curved laser beam L is projected onto the x-axis, a continuous straight line without breaks is obtained. That is, the irradiation positions of the laser beam L are arranged continuously in the x direction as the second direction. This means that the laser beam L is irradiated evenly along the x direction. Therefore, the welding quality along the x direction can be stabilized. Similarly, when the irradiation locus of the curved laser beam L is projected onto the y-axis, a continuous straight line without breaks is obtained. That is, the irradiation positions of the laser beam L are arranged continuously within the repetitive scanning range R along the y direction as the first direction. This means that the laser beam L is irradiated evenly along the y direction. Therefore, the welding quality along the y direction can be stabilized.

[0055] The conditions for realizing the continuity of the irradiation position of the laser beam L in the x direction as described above can be formulated as follows. As shown in FIG. 5C, let the forward amount by one forward movement F in the x scan be D, and the average traveling speed of the x scan be v. In the example of FIG. 5C where the intermittent irradiation period t is n = 3 times the traveling period T in the x direction, the scanning position of the laser beam L moves by nvT (= vt) in the x direction during the intermittent irradiation period t. In order to realize the continuity of the irradiation position of the laser beam L in the x direction, it is sufficient that the length of the range where the laser beam L is irradiated during one forward movement F (that is, the forward amount D) is equal to or greater than the total traveling amount nvT of the x scan for n times. That is, it is sufficient that D ≧ nvT is satisfied. For any positive number n (not necessarily a natural number) that satisfies this, it is preferable that the intermittent irradiation period t is defined as t = nT. In the example of FIG. 5B, n = 2.

[0056] As described above, the present disclosure has been described based on the embodiments. Various modifications are possible for the combination of each component and each process in the exemplary embodiments, and it is obvious to those skilled in the art that such modifications are included in the scope of the present disclosure.

[0057] The laser device 2 according to the present disclosure is not limited to the fiber laser device exemplified in the above embodiments. For example, a YAG (Yttrium Aluminum Garnet) or the like that can emit a laser beam with a larger diameter than the fiber laser device may be used as the laser device 2.

[0058] The laser scanning unit 17 according to the present disclosure is not limited to the galvanometer scanner 14 exemplified in the above embodiments. For example, a robot such as a robot hand or a robot arm in which the laser device 2 is fixed or gripped at the tip or the like may be used as the laser scanning unit 17. Such a robot can drive the joints based on the drawing data or the scanning data given from the laser control unit 18 or the robot control unit, and can arbitrarily control the irradiation position and the irradiation direction of the laser beam L from the laser device 2.

[0059] Note that the configurations, operations, and functions of the respective devices and methods described in the embodiments can be realized by hardware resources or software resources, or by the cooperation of hardware resources and software resources. As hardware resources, for example, a processor, ROM, RAM, and various integrated circuits can be used. As software resources, for example, programs such as an operating system and applications can be used.

Description of Reference Numerals

[0060] 1 Laser processing apparatus, 2 Laser apparatus, 3 Object to be processed, 4 Stage apparatus, 14 Galvanometer scanner, 17 Laser scanning unit, 18 Laser control unit, 20 Optical fiber, L Laser beam.

Claims

1. A laser scanning unit that performs scanning by combining a first scan of a repetitive laser beam within a repetitive scanning range along a first direction and a second scan of the laser beam along a second direction intersecting the first direction; A laser control unit that intermittently emits the laser beam to a laser device during the scanning; A laser processing apparatus comprising the above.

2. The laser processing apparatus according to claim 1, wherein the second scan is a straight scan of the laser beam along the second direction.

3. In the second scan, the forward and backward movements of the laser beam along the second direction are alternately repeated, and each forward movement amount is greater than each backward movement amount. The laser processing apparatus according to claim 1.

4. The laser processing apparatus according to claim 3, wherein the laser control unit temporarily stops emitting the laser beam to the laser device within a range where the forward and backward movements overlap in the second direction.

5. The laser processing apparatus according to claim 4, wherein the irradiation positions of the laser beam are arranged continuously in the second direction.

6. The laser control unit alternately repeats a predetermined emission period during which the laser device emits the laser beam and a predetermined stop period during which the laser device stops emitting the laser beam. In the second scan, a predetermined forward period during which the laser beam is advanced along the second direction and a predetermined backward period during which the laser beam is retracted along the second direction are alternately repeated. A travel cycle, which is the sum of the forward period and the backward period, is shorter than an intermittent emission cycle, which is the sum of the emission period and the stop period. The laser processing apparatus according to claim 4.

7. The laser processing apparatus according to claim 6, wherein the intermittent emission cycle is a natural number multiple of the travel cycle.

8. The laser control unit alternately repeats a predetermined emission period during which the laser device emits the laser beam and a predetermined stop period during which the laser device stops emitting the laser beam. A repetition cycle of the first scan is shorter than an intermittent emission cycle, which is the sum of the emission period and the stop period. The laser processing apparatus according to any one of claims 1 to 7.

9. The laser processing apparatus according to claim 8, wherein the intermittent emission cycle is a natural number multiple of the repetition cycle.

10. The laser processing apparatus according to any one of claims 1 to 7, wherein the irradiation positions of the laser beam are arranged continuously within the repetitive scanning range along the first direction.

11. The laser processing apparatus according to any one of claims 1 to 7, wherein the first scanning is a reciprocating scan of the laser beam within the repeated scan range.

12. A laser processing apparatus that performs laser processing for welding a workpiece having a gap along the first direction and extending along the second direction with the laser beam, wherein the gap is included within the repeated scan range in the first direction. The laser processing apparatus according to any one of claims 1 to 7.

13. The laser processing apparatus according to any one of claims 1 to 7, wherein the laser device is a fiber laser device that emits the laser beam through an optical fiber.

14. Performing a scan that combines a first scan of the laser beam repeatedly within a repeated scan range along a first direction and a second scan of the laser beam along a second direction intersecting the first direction; Intermittently emitting the laser beam to a laser device during the scan; A laser processing method for executing the above.

15. Performing a scan that combines a first scan of the laser beam repeatedly within a repeated scan range along a first direction and a second scan of the laser beam along a second direction intersecting the first direction; Intermittently emitting the laser beam to a laser device during the scan; A storage medium storing a laser processing program for causing a computer to execute the above.

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