JP2019005802A - Laser processing method, laser processing device and laser emission unit - Google Patents

Abstract

[Problem] To efficiently and simply perform the same type of laser processing with different laser energies at a desired ratio for two processing points set close to each other on a workpiece. [Solution] This emission unit 10 is provided with a distance adjustment section 42, an offset adjustment section 44, and a direction adjustment section 45 in or around the secondary cylinder 18b. The distance adjustment section 42 is for adjusting the relative positional relationship between the end face of the optical fiber 12 and the roof-type prism 38 in a first direction (X direction) on the optical axis (center axis) of the collimator lens 32. The offset adjustment section 44 is for adjusting the relative positional relationship between the roof-type prism 38 and the end face of the optical fiber 12 in a second direction in the YZ plane perpendicular to the first direction (X direction). The direction adjustment section 45 is for adjusting the direction (orientation) of the roof-type prism 38 in the rotational direction (θA direction) of the optical axis of the collimator lens 32. [Selected Figure] Figure 1

Description

  The present invention relates to a fiber transmission type laser processing method, a laser processing apparatus, and a laser emission unit.

  The laser processing apparatus of the fiber transmission system connects the apparatus main body and the laser emission unit that are spatially separated by an optical fiber, transmits the laser beam generated in the apparatus main body to the laser emission unit through the optical fiber, A laser beam is focused and irradiated toward the workpiece on the laser emission unit side.

  The fiber transmission system is often used for multi-point simultaneous processing. Conventionally, when a fiber transmission method is used for multi-point simultaneous processing, an original laser beam generated by a single laser oscillator is divided into a plurality of branched laser beams by a beam splitter composed of a partial reflection mirror, and the plurality of branches are divided. A laser beam is transmitted through an optical fiber to a plurality of laser emission units arranged at remote processing locations, and a plurality of branched laser beams are simultaneously irradiated from the plurality of laser emission units toward a plurality of processing points. System configuration is adopted.

JP 2014-65047 A

  As one form of multi-point simultaneous machining, two machining points separated by a minute distance of about several millimeters are set on the workpiece, and two branched laser beams with different laser outputs are simultaneously irradiated to these two machining points. Thus, there are uses or applications in which the same kind of laser processing with different laser energy is simultaneously performed.

  For such applications, the conventional general fiber transmission system as described above uses a plate-shaped beam splitter whose transmittance and reflectance continuously change in a predetermined direction on the plate surface. By changing the relative incident position of the original laser beam with respect to the splitter in the predetermined direction, the two branched laser beams obtained from the beam splitter, that is, the first branched laser beam transmitted through the beam splitter and the reflected beam by the beam splitter Although the laser output ratio (division ratio) is variably adjusted with the second branched laser beam (see FIG. 10 of Patent Document 1), the entire system is large and not cost effective. . Furthermore, when simultaneously processing from two or more independent emission units to a machining location having a narrower interval than the diameter of the emission unit, the two laser emission units separated from each other on the left and right are arranged in an inclined posture. Since the branched laser beam is incident on the machining point at an oblique incident angle, there is a problem that the penetration depth in the plate thickness direction decreases at the machining point, or when the distance or direction of the two machining points on the workpiece changes However, there is a problem that fine adjustment is difficult because the arrangement position and the inclination posture of the entire laser emission unit must be changed.

  In order to avoid the above-mentioned problems associated with multi-point simultaneous processing, a non-branching single laser emission unit is used, and the irradiation point of the laser beam from the emission unit is moved for each processing point, and the laser An original laser beam adjusted to a desired laser output on the oscillating unit side is transmitted through an optical fiber to a laser emission unit, and is irradiated on a processing point below the laser emission unit. However, such a method of irradiating the original laser beam one by one for each processing point has a problem that the tact time is doubled and the production efficiency is low.

  The present invention solves such problems of the prior art, and efficiently performs the same kind of laser processing in which the laser energy is different at a desired ratio with respect to two processing points set close to each other on the workpiece. Provided are a laser processing method, a laser processing apparatus, and a laser emitting unit used therefor, which can be easily performed.

  The laser processing method of the present invention generates an original laser beam having a predetermined laser output in a laser oscillation unit, transmits the original laser beam from the laser oscillation unit via an optical fiber to a remote laser emission unit, In the laser emitting unit, the original laser beam that has exited from the end face of the optical fiber is incident on a roof-type prism arranged at a predetermined position, and at this time, the beam center of the original laser beam is the roof-type prism. The original laser beam is divided into first and second branched laser beams having different laser power at a desired ratio so as to be shifted from the ridgeline of the inclined surface by a desired offset amount in a direction orthogonal thereto, and the laser emitting unit The collimating laser is disposed at the subsequent stage of the first and second branched laser beams emitted from the roof prism. Each of the first and second branched laser beams emitted from the collimating lens is passed through a condensing lens disposed in a subsequent stage in the laser emitting unit, and the laser emitting unit The first and second branch laser beams emitted from the condenser lens are focused and irradiated to the first and second machining points on the workpiece disposed outside, respectively, and the laser energy is reduced. Different laser processing is performed simultaneously.

  According to the laser processing method of the present invention, since the laser powers of the first and second branched laser beams obtained by passing the original laser beam through the roof prism are different by a desired ratio, Even when, for example, the material of the workpiece is different between the second machining points or when the heat input or heat dissipation characteristics are different, both of the machining points can be appropriately and satisfactorily subjected to laser processing.

  The laser emitting unit according to the present invention condenses and irradiates the first and second laser beams to the first and second processing points on the workpiece to simultaneously perform laser processing with different laser energies. A casing having an optical fiber mounting port for mounting one end of an optical fiber through which an original laser beam from a laser oscillation unit propagates and a laser output port directed to the workpiece And the first laser beam emitted from the end surface of the optical fiber is disposed in the casing so that the incident surface thereof faces the end surface of the optical fiber mounted in the optical fiber mounting port. A roof-type prism that is divided into a second branched laser beam; and a roof-type prism that is disposed in the casing so as to face an emission surface of the roof-type prism. A collimating lens for collimating each of the first and second branched laser beams, and the first and second branched laser beams from the collimating lens disposed in the casing in proximity to the laser emission port. A condensing lens for condensing the first and second processing points on the workpiece located outside the casing; and the roof prism in a first direction parallel to the optical axis of the collimating lens. A first position adjusting unit for variably adjusting a relative positional relationship between the optical fiber mounting port and the roof-type prism in a second direction in a plane perpendicular to the optical axis of the collimating lens; A second position adjusting unit for variably adjusting a relative positional relationship with the emission end face of the optical fiber.

  According to the laser emission unit having the above-described configuration, the adjustment function of the first and second position adjustment units allows a desired laser power of the first and second branched laser beams obtained by passing the original laser beam through the roof prism. It can be varied in ratio.

  The laser processing apparatus of the present invention includes a laser oscillation unit that oscillates and outputs an original laser beam for laser processing, the laser emission unit of the present invention, and the laser beam emitted from the laser oscillation unit. First and second beams emitted from the laser emitting unit with respect to first and second machining points separated from each other by a predetermined distance on the workpiece. Each of the branched laser beams is condensed and irradiated, and laser processing with different laser energy is simultaneously performed.

  According to the laser processing apparatus of the present invention, by including the laser emission unit of the present invention, for example, when the material of the workpiece is different between the first and second processing points on the workpiece, Or, even when the heat dissipation characteristics are different, appropriate and good laser processing can be performed simultaneously at both processing points.

  According to the laser processing method, the laser processing apparatus, or the laser emission unit of the present invention, a laser having a desired ratio with respect to two processing points set close to the workpiece by the configuration and operation as described above. The same kind of laser processing with different energies can be performed efficiently and simply.

It is a schematic sectional drawing which shows the structure of the laser emission unit in one Embodiment of this invention. It is a figure which shows the laser welding process of the 1st example in embodiment. It is a figure which shows the laser welding process of the 2nd example in a comparative example. It is a figure which shows the laser welding process of the said 2nd example in embodiment. It is a figure which shows one effect | action of the said laser emission unit. It is a figure which shows one effect | action of the said laser emission unit. It is a figure which shows one effect | action of the said laser emission unit. It is a side view which shows the structure of the principal part of the said laser emission unit. It is a longitudinal cross-sectional view which shows the structure of the principal part of the said laser emission unit. It is a longitudinal cross-sectional view which shows the structure of the principal part of the said laser emission unit. It is a figure which shows the structure of the direction adjustment part in one Example. It is a figure which shows the structure of the direction adjustment part in another Example. It is a figure for demonstrating an effect | action of the direction adjustment part of FIG. 11A.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[Configuration and operation of the whole emission unit in the embodiment]

  FIG. 1 shows a configuration of a laser emission unit in an embodiment of the present invention. This laser emitting unit 10 is used in a fiber transmission type laser processing apparatus such as a laser welding apparatus. The apparatus main body (not shown) including a laser oscillation unit is a cable such as an optical fiber 12, a light guide 14 and an electric cord 16. It is connected through a kind, and is arranged or installed in an arbitrary posture at an arbitrary processing place.

  The emission unit 10 includes a resin-made or metal-made casing 18 composed of a single or a plurality of cylinders, and arranges or accommodates necessary optical components in the casing 18, Necessary adjustment parts and accessory parts are provided around. The casing 18 has a main cylinder 18a extending in the longitudinal direction (vertical direction in FIG. 1), and first and second sub-cylinders 18b and 18c extending in the short direction (lateral direction in FIG. 1). Yes.

  The main cylindrical body 18a has a laser emission port 20 formed at one end (lower end), and an imaging device such as a CCD camera 22 attached to the other end (upper end). A protective glass 24 is attached to the laser emission port 20, and a condenser lens 26 is disposed near the inside thereof. On the optical axis of the condenser lens 26, the first and second bend mirrors 28, 30 are located with respect to the optical axis of the condenser lens 26 at locations that intersect the first and second sub-cylinders 18 b, 18 c. In a posture inclined at a predetermined angle (generally 45 °). A video lens 32 including a condensing lens and a beam expander for forming an image of the workpiece W on the imaging surface of the CCD camera 22 is provided on the main cylinder 18a. The CCD camera 22 is electrically connected to a power source, a display unit and the like in the apparatus main body via an electric cord 16.

  Inside the first sub cylinder 18b, a collimator lens 34 is fixedly disposed at a position close to the main cylinder 18a, and a ridgeline is formed so that the flat surface (outgoing surface) faces the collimator lens 34. A roof-type prism 38 having 38c is disposed between the collimating lens 34 and the optical fiber attachment port 36 located at the tip of the sub cylinder 18b.

  One end portion or a terminal end portion of the optical fiber 12 is detachably attached to the optical fiber attachment port 36 via the optical fiber holding portion 40. The other end (not shown) of the optical fiber 12 is optically coupled to a laser oscillation unit (for example, a solid laser such as a YAG laser, a fiber laser, or a semiconductor laser) in the apparatus main body.

The emission unit 10 includes three adjustment units, that is, a distance adjustment unit 42, an offset adjustment unit 44, and a direction adjustment unit 45 in or around the sub cylinder 18b. The distance adjustment unit 42 determines the relative positional relationship between the end face of the optical fiber 12 and the roof prism 38 that face each other in the first sub cylinder 18b, and the optical axis (center axis) of the collimating lens 34. This is for adjustment in the first direction (X direction). The offset adjustment unit 44 adjusts the relative positional relationship between the roof prism 38 and the end face of the optical fiber 12 in a second direction in the YZ plane orthogonal to the first direction (X direction). Is. Direction adjustment unit 45 is for adjusting the direction of the roof prism 38 (orientation) in the circumferential direction of the optical axis of the collimating lens 34 (theta _A direction). The configuration and operation of each adjustment unit 42, 44, 45 will be described in detail later.

  Inside the second sub cylinder 18c, an illumination collimating lens 46 is fixedly disposed at a position close to the main cylinder 18a. One end of the cable-type light guide 14 is detachably attached to the light guide attachment port 48 located at the distal end of the sub cylinder 18c via a connector (not shown). The other end (not shown) of the light guide 14 is optically coupled to an illumination light source (for example, a light emitting diode) in the apparatus main body.

In the laser welding apparatus including the laser emitting unit 10 having the above-described configuration, one or a plurality of sets of _two welding points P ₁ and P ₂ are set on the workpiece W at a desired distance, and welding of each set is performed. Laser spot welding with different laser energies can be simultaneously performed by simultaneously irradiating the points P ₁ and P ₂ with two branched laser beams LB ₁ and LB ₂ having different laser powers at an arbitrary ratio.

In this case, the original laser beam LB ₀ oscillated and output from the laser oscillation unit in the apparatus main body is transmitted to the remote laser emission unit 10 via the optical fiber 12. Then, the original laser beam LB ₀ emitted from the emission end face of the optical fiber 12 in the first sub-cylinder 18b with a certain divergence angle is incident on the ridge line 38c when entering the inclined surface of the roof prism 38. When incident, it is divided into left and right (up and down in FIG. 1) around the ridge line 38c. Thus, the first and second branched laser beams LB ₁ and LB _{2 that} are split into two at a certain acute angle are emitted from the exit surface (flat surface) of the roof-type prism 38 toward the collimator lens 34.

The branched laser beams LB ₁ and LB ₂ divided and generated by the roof prism 38 are collimated by the collimating lens 34 and then perpendicularly directed toward the laser emission port 20 by the first bend mirror 28 in the main cylindrical body 18a. Wrapped. The bend mirror 28 is a dichroic mirror and coats a film that is reflective to the infrared branched laser beams LB ₁ and LB ₂ and a film that is transmissive to illumination light and visible light.

The first and second branched laser beams LB ₁ and LB ₂ folded back to the laser emission port 20 side by the bend mirror 28 pass through the condensing lens 26 and the protective lens 24 and pass through the laser emission port 20 to the laser emission unit 10. The light is emitted to the outside and is focused and incident on the welding points P ₁ and P ₂ on the workpiece W, respectively. At each of the welding points P ₁ and P ₂ , the work material is melted by the laser energy of the corresponding branched laser beams LB ₁ and LB ₂ , and the molten pool is solidified after laser irradiation to form a weld nugget.

On the other hand, when laser welding is performed, beam-like illumination light GB emitted from the illumination light source in the apparatus main body is sent to the laser emission unit 10 via the light guide 14. The illumination light GB emitted from the exit end face of the light guide 14 passes through the collimating lens 46 in the second sub-cylinder 18c, the bend mirror 30, the condensing lens 26, and the protective lens 24 in the main cylinder 18a to be processed. It enters the object W and shines brightly around the welding points P ₁ and P ₂ . The bend mirror 30 is a dichroic mirror that reflects the illumination light GB and transmits visible light.

The CCD camera 22 images the welding points P ₁ and P ₂ on the workpiece W and the surroundings thereof through the video lens 32, the bend mirrors 30 and 28, the condenser lens 26 and the protective glass 24. That is, the visible light VB from the vicinity of the welding points P ₁ and P ₂ passes through the protective glass 24, the condenser lens 26, the bend mirrors 28 and 30, and the video lens 32 and enters the imaging surface of the CCD camera 22. The image formed on the light receiving surface is converted into an electrical signal, that is, an image signal. The image signal generated by the CCD camera 22 is sent to the apparatus main body via the electric cord 16. Images near the welding points P ₁ and P _{2 of the} workpiece W are displayed on the display on the apparatus main body side.

  Here, some examples of suitable laser processing of the laser welding apparatus and laser welding method in this embodiment will be shown.

  FIG. 2 shows an example of laser welding processing in which the FFC cable 106 is joined to the wiring pattern 102 on the printed circuit board 100 via a plate-like or foil-like solder 104. FIGS. 2A and 2B show the structure of the workpiece W to be laser-welded in a plan view and a cross-sectional view, respectively.

In this laser welding process, welding points P ₁ and P ₂ are set on the exposed portion of the plate-like solder 104 and one end of the FFC cable 106, respectively, and laser spot welding is simultaneously performed on both the welding points P ₁ and P ₂ . . Here, welded with one weld point P ₁ in the solder 104 and the wiring pattern 102, welding the other at the welding point _{P 2} and the FFC cable 106 and the solder 104. The material of the material to be welded is different at the two welding points P ₁ and P ₂ , and the laser power one step or several steps higher at the welding point P ₂ than at the welding point P ₁ is required.

In this case, when the same proper welding results laser power of both branches the laser beam LB _1, LB ₂ as obtained in the welding points P ₁ side, penetration is insufficient for FFC cable 106 by welding points P ₂ side The welding strength is insufficient. Conversely, when the same proper welding results laser power of both branches the laser beam LB _1, LB ₂ as obtained in the welding points P ₂ side, penetration of the solder 104 and the pattern wiring 102 by welding points P ₁ side An excessive amount may burn the substrate 100 or the adhesive on the surface thereof.

According to the laser emission unit 10 of this embodiment, for such laser welding, assuming that the laser power of both branched laser beams LB ₁ and LB ₂ is PW ₁ and PW ₂ , for example, as shown in FIG. Thus, by setting an appropriate ratio (for example, PW ₁ : PW ₂ = 4: 6) in the relationship of PW ₁ <PW ₂ , for two welding points P ₁ and P ₂ having different materials of the welded material Optimum laser power or laser energy is supplied, respectively, and appropriate and good weld joints can be obtained simultaneously at both welding points P ₁ and P ₂ .

3 and 4, in the case of laser spot welding of a lap joint, a case where one welding point P ₁ is set at the edge of the workpiece and the other welding point P ₂ is set in a region inside it. Show. In this case, as shown in FIG. 3 ((a) is a plan view and (b) is a cross-sectional view), the laser powers of the branched laser beams LB ₁ and LB ₂ incident on both welding points P ₁ and P ₂ are the same. In this case, poor welding occurs at least one of the two welding points P ₁ and P ₂ . That is, when the laser powers of the branched laser beams LB ₁ and LB ₂ are optimized with respect to the inner welding point P ₂ with good heat absorption, the heat input of the laser is accumulated at the welding point P _{1 on the} edge side with poor heat absorption. The workpiece W (W _U , W _L ) is easily damaged. On the other hand, when the laser powers of the branched laser beams LB ₁ and LB ₂ are optimized with respect to the welding point P ₁ on the end side, the laser energy is insufficient at the inner welding point P ₂ and the welding nugget tends to be too small.

According to the laser emitting unit 10 of this embodiment, even in such laser welding processing, as shown in FIG. 4 ((a) is a plan view and (b) is a cross-sectional view), both branched laser beams LB ₁ , By setting the laser powers PW ₁ and PW ₂ of LB _{2 to} an appropriate ratio in the relationship of PW ₁ <PW ₂ , appropriate laser energy is supplied to both the welding points P ₁ and P ₂ , respectively. A welding result can be obtained.

When two-point simultaneous welding is performed on the workpiece W using the laser emission unit 10 of this embodiment, the original laser beam LB ₀ is divided into two in the casing 18 (sub cylinder 18b) of the laser emission unit 10. Thus, the first and second branched laser beams LB ₁ and LB ₂ are generated, and these branched laser beams LB ₁ and LB ₂ are supplied to the two workpieces W on the workpiece W via the collimator lens 34 and the condenser lens 26. Condensation irradiation is simultaneously performed on the welding points P ₁ and P ₂ . The apparatus main body only needs to have one incident unit for inputting the original laser beam LB ₀ to the optical fiber 12. A separate beam splitter for dividing the original laser beam LB ₀ into two parts is unnecessary. There is no need to provide multiple units. Of course, only one optical fiber 12 is required. Moreover, since two laser beams LB ₁ and LB ₂ are simultaneously irradiated from the respective front surfaces toward _two welding points P ₁ and P ₂ on the workpiece W from one laser emitting unit 10, each welding is performed. At points P ₁ and P ₂ , the penetration depth in the plate thickness direction can be made sufficiently large to improve the joint strength of two-point simultaneous welding.

[Effects of Main Parts in Embodiment]

In this embodiment, the relative positional relationship between the end surface of the optical fiber 12 and the roof-type prism 38 can be arbitrarily adjusted in the X direction by the distance adjusting unit 42, and the offset adjusting unit 44 can adjust the relative position relationship in the YZ plane. The direction adjustment unit 45 can arbitrarily adjust the direction (direction) of the roof prism 38 in the direction of the optical axis of the collimator lens 34 (θ _A direction). It is like that.

Then, as will be described in detail below, the distance adjustment unit 42 is used to adjust the relative position of the roof prism 38 with respect to the end surface of the optical fiber 12 in the X direction so that the workpiece W can be adjusted. The distance D between the beam spots BS ₁ and BS _{2 of the} two branched laser beams LB ₁ and LB ₂ can be arbitrarily adjusted within a certain range. More specifically, the distance D between the beam spots is reduced as the roof-type prism 38 is brought closer to the emission end face of the optical fiber 12 in the first sub-cylinder 18b, and the roof-type prism 38 is moved away from the emission end face of the optical fiber 12. As a result, the distance D between the beam spots can be increased. Further, the offset position adjusting unit 44 is used to set the relative position of the roof prism 38 with respect to the end surface of the optical fiber 12 in the second direction in the YZ plane (particularly, the direction orthogonal to the ridge line 38c of the roof prism 38). The laser power ratio between the two branched laser beams LB ₁ and LB ₂ can be arbitrarily adjusted by variably adjusting the laser beam. Further, by using the direction adjustment unit 45, by adjusting the orientation or direction of the roof prism 38 in the circumferential direction of the optical axis of the collimating lens 34 (theta _A direction), both branches the laser beam LB on the workpiece W The direction or direction of the beam spots BS ₁ and BS ₂ of ₁ and LB ₂ can be arbitrarily adjusted.

  5A and 5B show the optical components of the main optical components, that is, the optical fiber 12, the roof prism 38, the collimator lens 34, and the condenser lens 26, which are related to the generation, splitting adjustment and emission of the branched laser beam in the laser emission unit 10. The arrangement and the operation of the main part are shown.

FIG. 5A shows a case where the position of the roof prism 38 is adjusted in the vicinity of the collimating lens 34 farthest from the end face of the optical fiber 12. In this case, the original laser beam LB ₀ emitted from the end surface of the optical fiber 12 is incident on the inclined surface of the roof prism 38 after the beam diameter has expanded considerably. Here, as shown in (a) of FIG. 5A, when the center axis of the optical fiber 12 faces the ridge 38c and front of the roof prism 38, the original laser beam LB half of ₀ (left half of FIG. ) Is incident on one inclined surface 38a of the roof-type prism 38 (left side in the figure), and the other half (right half in the figure) is incident on the other inclined surface 38b of the roof-type prism 38 (right side in the figure). Then, the left half of the original laser beam LB ₀ incident on the left inclined surface 38a is refracted obliquely to the right to become the first branched laser beam LB _1. Conversely, the original laser beam LB ₀ incident on the right inclined surface 38b. The right half of the laser beam is refracted obliquely to the left side to become the second branched laser beam LB ₂ , and after exiting from the exit surface (flat surface) of the roof prism 38, the two branched laser beams LB ₁ and LB ₂ are switched in the left-right direction. In this way, the first and second branched laser beams LB ₁ and LB _{2 that} are split into left and right at a certain acute angle are emitted from the exit surface (flat surface) of the roof prism 38 to the collimator lens 34 side.

The bifurcated laser beams LB ₁ and LB ₂ that have passed through the collimating lens 34 then pass through the condenser lens 26, and are condensed toward the imaging positions corresponding to the focal length of the condenser lens 26. As a result, as shown in (a) of FIG. 5A, with the same laser power at a workpiece W beam spot distance D _M of the maximum adjustable on top (not shown in FIG. 5A) beam spot BS ₁ of both branches the laser beam LB _1, LB _2, BS ₂ is formed.

Then, the offset adjusting unit 44 adjusts the relative position of the roof prism 38 with respect to the end surface of the optical fiber 12 in one direction in the XY plane perpendicular to the ridge line 38 c of the roof prism 38, so that both branched lasers are obtained. The laser power ratio between the beams LB ₁ and LB ₂ can be arbitrarily adjusted. That is, when the end face of the optical fiber 12 is relatively shifted from the state of FIG. 5A to the right side of the drawing, the majority of the original laser beam LB ₀ is roofed as shown in FIG. 5B. Since the laser beam is incident on the inclined surface 38b on the right side of the mold prism 38, the split ratio of the laser beams is not the same on the left and right, and the laser power of the _second branched laser beam LB2 is proportional to the shift amount. It is higher than the laser power of the branch laser beam LB ₁ of. On the contrary, when the end surface of the optical fiber 12 is relatively shifted to the left side of the drawing, the majority of the original laser beam LB ₀ is inclined on the left side of the roof prism 38 as shown in FIG. to enter the 38a, the first laser power branch the laser beam LB ₁ is higher than the second laser power branch the laser beam LB ₂ in proportion to the shift amount.

By the offset adjustment function of the offset adjustment unit 44 as described above, the laser power ratio of both the branched laser beams LB ₁ and LB ₂ is arbitrarily set within a range of 50:50 to 1:99 and a range of 50:50 to 99: 1, for example. Further, when the original laser beam is incident only on one inclined surface of the roof prism, only one of the laser beams LB ₁ and LB ₂ is supplied to the original laser beam LB _0. It is also possible to emit as a non-branching laser beam corresponding to.

In the function of the distance adjustment unit 42, when the roof type prism 38 is moved to the end face side of the optical fiber 12, the optical path from the original laser beam LB ₀ exiting from the end face of the optical fiber 12 and entering the roof type prism 38. Is shortened, and both branched laser beams LB ₁ and LB ₂ coming out from the exit surface from the roof-type prism 38 approach the optical axis (center axis) of the collimating lens 34, and the respective beam spots on the workpiece W The distance D between BS ₁ and BS ₂ is reduced. When the roof prism 38 is disposed at the closest position within the adjustable range to the end face of the optical fiber 12, as shown in FIG. 5B (a), the workpiece W (not shown in FIG. 5B). In the above, the distance D between the beam spots BS ₁ and BS ₂ of the two branched laser beams LB ₁ and LB ₂ becomes the minimum value D _m that can be adjusted. Also in this case, similarly to the above, the offset power adjustment function of the offset adjuster 44 allows the laser power ratio of the two branched laser beams LB ₁ and LB _{2 to be} in the range of 50:50 to 1:99 and 50:50 to 99 :, for example. It is possible to adjust arbitrarily within the range of 1.

Furthermore, in this laser emission unit 10, by changing the direction of the roof prism 38 by the direction adjustment unit 45 and shifting the position of the end face of the optical fiber 12 in the direction in the YZ plane by the offset adjustment unit 44, optionally in both branches the laser beam LB _1, laser power workpiece to keeping constant ratio W on both the beam spot BS ₁ of LB _2, BS ₂ of aligned orientation or direction of the azimuth direction (theta _B direction) Can be adjusted.

In this case, from the state shown in (a) of FIG. 6, when the roof prism 38 is rotated by an arbitrary angle in the circumferential direction of the optical axis N _F of the collimating lens 34 (theta _A direction) on the workpiece W position of both the beam spots BS _1, BS ₂ is rotated by the same angle in the azimuthal direction (theta _B direction). However, if the rotation center (N _F ) of the roof type prism 38 and the beam center N _L of the original laser beam LB ₀ incident thereon do not overlap, as shown in FIG. , The relative incident position of the original laser beam LB ₀ with respect to the roof prism 38 (particularly the ridge line 38c) changes, and the power split ratio of the two branched laser beams LB ₁ and LB ₂ varies. In the example of FIG. 6B, the power split ratio varies in such a manner that the power of the branched laser beam LB ₁ increases and the power of the branched laser beam LB ₂ decreases. Therefore, as shown in FIG. 6C, the position of the end face of the optical fiber 12 is shifted in the direction of the arrow in the YZ plane, and the original laser beam LB _{0 with} respect to the roof type prism 38 (particularly the ridge line 38c). The relative incident position relationship is made the same as in FIG. Then, the power division ratio of the branched laser beams LB ₁ and LB ₂ is also the same as that shown in FIG.

[Specific Configuration Example of Main Part in Embodiment]

  7 to 10 show specific configuration examples of the distance adjusting unit 42, the offset adjusting unit 44, and the direction adjusting unit 45 provided in the sub-cylinder 18b of the laser emitting unit 10 in this embodiment. FIG. 7 is a schematic side view showing the structure around the sub-cylindrical body 18b as viewed from the outside of the fiber attachment port 36 (mainly the configuration of the offset adjusting unit 44). 8 and 9 are a longitudinal sectional view and a transverse sectional view showing the structure inside and around the sub-cylinder 18b (mainly the configuration of the distance adjusting unit 42 and the offset adjusting unit 44). FIGS. 10A and 10B are a schematic plan view (a) and a longitudinal sectional view showing the configuration of the direction adjustment unit 45. FIG.

  As shown in FIGS. 8 and 9, the distance adjusting unit 40 includes a prism support unit 50 that holds the roof prism 38 on the optical axis of the collimator lens 34 in the sub cylinder 18b, and a sub cylinder 18b. And a guide portion 52 for guiding the prism support portion 50 in the optical axis direction (X direction) of the collimator lens 34, and a feed screw mechanism 54 attached to the outer surface of the sub cylinder 18b.

  In the feed screw mechanism 54, when the head of the bolt 56 supported by the bearing 55 is turned, an arm-shaped movable member 58 that is screwed into the screw shaft of the bolt 56 and coupled to the prism support portion 50 is formed. The bolt 56 is fed in the axial direction, that is, in the X direction. The prism support part 50 and the roof type prism 38 move or displace in the same direction as the movable member 58 while being guided by the guide part 52 having a guide function in the X direction. The direction of this movement (forward or backward) is determined by the direction of rotation of the bolt 56. A lock mechanism (not shown) for fixing the position of the prism support portion 50, that is, the position of the roof prism 38 may be provided in the feed screw mechanism 54 or the guide portion 52.

  The offset adjustment unit 44 includes a Z direction offset adjustment unit 60 and a Y direction offset adjustment unit 62. The Z-direction offset adjusting unit 60 is adjacent to the end surface (outer surface) of the sub-cylindrical body 18b and can be displaced or moved in the Z-direction orthogonal to the X-direction, and the Z-direction slide plate 64 is moved to the Z-direction. A Z-direction feed screw mechanism 66 and a Z-direction guide portion 68 for displacing or moving in the direction, and one for urging the Z-direction slide plate 64 from the opposite side against the forward drive of the Z-direction feed screw mechanism 66 or A plurality of compression coil springs 70 and one or a plurality of bolts 72 for fixing the Z-direction slide plate 64 at a desired slide position are provided.

  At the center of the Z-direction slide plate 64, an opening 64c is formed through which the end portion of the optical fiber 12 can be displaced in the YZ direction (particularly the Y direction). The Z-direction guide portion 68 includes a pair of parallel guide plates 74A and 74B that are fixed to the end surface of the sub cylinder 18b. The pair of parallel guide plates 74 </ b> A and 74 </ b> B extend parallel to the Z direction with a certain interval corresponding to the width size of the Z direction slide plate 64. The Z-direction slide plate 64 is attached to be slidable in the Z-direction so that the pair of side portions 64a and 64b facing each other are engaged with the parallel guide plates 74A and 74B, respectively. In the Z-direction feed screw mechanism 66, when the head of the bolt 78 supported by the bearing 76 fixed to the sub cylinder 18b is turned, the head is screwed into the screw shaft of the bolt 74 and the Z-direction slide plate 64 is engaged. The connected block-shaped movable member 79 is fed together with the slide plate 64 in the axial direction of the bolt 76, that is, in the Z direction. The compression coil spring 70 is stretched between the sub cylinder 18b and the Z-direction slide plate 64. The bolt 72 is screwed into the screw hole 75 provided in at least one of the parallel guide plates 74A and 74B from the outside to press and fix the Z-direction slide plate 64.

  The Y-direction offset adjustment unit 62 is attached on the Z-direction slide plate 64 of the Z-direction offset adjustment unit 60. The Y-direction offset adjustment unit 62 includes a Y-direction slide plate 80 that can be displaced or moved in the Y direction on the Z-direction slide plate 64, and a Y-direction feed screw for displacing or moving the Y-direction slide plate 80 in the Y direction. A mechanism 82, a Y-direction guide portion 84, one or more compression coil springs 86 that urge the Y-direction slide plate 80 from the opposite side against the forward drive of the Y-direction feed screw mechanism 82, and a Y-direction slide. It has one or a plurality of bolts 88 for fixing the plate 80 at a desired slide position.

  At the center of the Y-direction slide plate 80, an opening 80c is formed through which the end of the optical fiber 12 is displaceable in the YZ direction. The Y direction guide portion 84 is composed of a pair of parallel guide plates 90A and 90B fixed to the Z direction slide plate 64. These parallel guide plates 90 </ b> A and 90 </ b> B extend in parallel to the Y direction with a certain interval corresponding to the width size of the Y-direction slide plate 80. The Y-direction slide plate 80 is attached so as to be slidable in the Y-direction so that the pair of opposite side portions are engaged with the parallel guide plates 90A and 90B, respectively. In the Y-direction feed screw mechanism 82, when the head of the bolt 94 supported by the bearing 92 fixed to the Z-direction slide plate 64 is turned, the head is screwed into the screw shaft of the bolt 94 and the Y-direction slide plate. A block-shaped movable member 96 coupled to 80 is fed together with the slide plate 80 in the axial direction of the bolt 94, that is, in the Y direction. The compression coil spring 86 is stretched between the Z-direction slide plate 64 and the Y-direction slide plate 80. The bolt 88 is screwed from the outside into a screw hole 95 provided in at least one of the parallel guide plates 90A and 90B to press and fix the Y-direction slide plate 80.

  In the offset adjustment unit 44 of this embodiment, the Z-direction offset adjustment function of the Z-direction offset adjustment unit 60 and the Y-direction offset adjustment function of the Y-direction offset adjustment unit 62 as described above are used to transmit light to the roof prism 38. The position of the end face of the fiber 12 can be adjusted in the Z direction and the Y direction in the YZ plane orthogonal to the adjustment direction (X direction) of the distance adjustment unit 40.

  The connector 65 is made of a ferrule or any other optical connector, is attached to the Y-direction slide plate 80, and constitutes the optical fiber holding unit 40 (FIG. 1). The end of the optical fiber 12 passes through the connector 65, passes through the respective openings of the Y-direction slide plate 80 and the Z-direction slide plate 64, and faces the roof-type prism 38 in the sub cylinder 18b. Alternatively, the optical fiber 12 terminates inside the connector 65, and the other end of the light guide member (not shown) whose one end is optically coupled to the end of the optical fiber 12 is the Y-direction slide plate 80 and the Z-direction slide plate. You may oppose the roof-type prism 38 in the sub cylinder 18b through 64 each opening.

As shown in FIG. 10, the direction adjusting unit 45 holds the prism support 50, the base 100 fixed to the movable member 80 (FIG. 9) of the Z-direction feed screw mechanism 66, and the roof-type prism 38. divided into a part 102, and any rotatable displacement within a range of 360 ° in the circumferential direction (theta _a direction) of the holding portion 102 on the base portion 100. More specifically, the base portion 100 has a laser light path through hole 100a at the center, and a recess 100b around the through hole 100a. The holding part 102 has a through hole 102a for the laser beam path in the center, and has a recess 102b around the through hole 102a. The roof prism 38 is fixedly attached to the recess 102b of the holding part 102, and the holding part 102 is attached to the recess 100b of the base part 100 so as to be capable of rotational displacement. Then, the roof-type prism 38 can be fixed in a desired direction by, for example, pressing and fixing the holding portion 102 to the base portion 100 with a bolt 104. In addition, in order to enable the direction adjustment work of the roof-type prism 38 in the direction adjustment part 45, the sub cylinder 18b can be disassembled by removing the bolt 106 (FIG. 9), for example.

[Other Embodiments or Modifications]

  11A and 11B show another embodiment of the direction adjustment unit 45. FIG. In this embodiment, the holding portion 102 ′ holding the roof prism 38 can be displaced in the Z direction by a pair of Z-direction feed screw mechanisms 110A and 110B and compression coil springs 112A and 112B on the base portion 100 ′. . Here, the Z-direction feed screw mechanisms 110A and 110B support the bolts 113A and 113B with bearings 111A and 111B fixed on the base portion 100 ′, respectively, and the tips of the bolts 113A and 113B are part of the holding portion 102 ′. By holding the heads of the bolts 113A and 113B against the side surfaces, the holding portion 102 ′ is advanced or retracted against the compression coil springs 112A and 112B. In the holding portion 102 ′, guide grooves 114 </ b> A and 114 </ b> B extending in the Z direction are formed on both sides of the roof prism 38. On the base portion 100 ′, pins 116 </ b> A and 116 </ b> B that pass through these guide grooves 114 </ b> A and 114 </ b> B are erected.

  As shown in FIG. 11B, the head J of the pin 116A (116B) is much larger than the groove width of the guide groove 114A (114B), and the shaft portion K of the pin 116A (116B) is the groove width of the guide groove 114A (114B). The gap is small enough to create a gap. That is, the shaft portion K of the pin 116A (116B) can be displaced not only relatively in the Z direction but also slightly in the Y direction within the guide groove 114A (114B). Accordingly, when the holding portion 102 ′ is moved in the Z direction on the base portion 100 ′, an appropriate difference in feed amount is provided between the Z-direction feed screw mechanisms 110A and 110B. As shown in (c), the shaft portion K of the pin 116A (116B) is relatively displaced in the Y direction in the guide groove 114A (114B), so that the holding portion 102 ′ is within a certain range (for example, 15 °). Can be arbitrarily rotated and displaced.

  Although not shown in the drawings, the casing 18 (sub-cylinder 18b) of the emission unit 10 has a configuration in which the orientation of the incident surface / exit surface of the roof prism 38 is opposite to the orientation of the above embodiment, that is, the convex surface of the roof prism 38 ( An arrangement in which the inclined surfaces 38a and 38b and the ridge line 38c) are directed toward the collimating lens 34 is also possible. Further, in the offset adjusting unit 44, for example, a configuration in which the Y direction offset adjusting unit 62 is omitted and only the Z direction offset adjusting unit 60 is provided is also possible.

  The laser processing apparatus of the present invention is not limited to laser welding, and can be used for other laser processing such as drilling and cutting.

10 Laser emission unit
DESCRIPTION OF SYMBOLS 12 Optical fiber 18 Casing 20 Laser output port 18a Main cylinder 18b 1st subcylinder 34 Collimate lens 36 Optical fiber installation port 38 Roof type prism 42 Distance adjustment part 44 Offset adjustment part 45 Direction adjustment part

Claims (6)

Generate an original laser beam having a predetermined laser output in the laser oscillation unit,
Transmit the original laser beam from the laser oscillation unit to a remote laser emission unit via an optical fiber,
In the laser emitting unit, the original laser beam emitted from the end face of the optical fiber is incident on a roof-type prism arranged at a predetermined position, and at this time, the beam center of the original laser beam is the roof-type prism. The original laser beam is divided into first and second branched laser beams having different laser power at a desired ratio so as to be shifted from the ridge line of the inclined surface by a desired offset amount in a direction perpendicular thereto.
In the laser emitting unit, the first and second branched laser beams emitted from the roof prism are respectively collimated through a collimating lens disposed in the subsequent stage,
In the laser emitting unit, the first and second branched laser beams emitted from the collimating lens are passed through a condensing lens disposed in the subsequent stage,
Condensing and irradiating the first and second branch laser beams emitted from the condenser lens to the first and second processing points on the workpiece disposed outside the laser emitting unit, respectively. To perform laser processing with different laser energy at the same time,
The laser processing method characterized by the above-mentioned. A laser emitting unit for condensing and irradiating the first and second laser beams to the first and second processing points on the workpiece and simultaneously performing laser processing with different laser energies,
A casing having an optical fiber mounting port for mounting one end of an optical fiber through which an original laser beam from a laser oscillation unit propagates, and a laser output port directed to the workpiece;
The first laser beam and the second laser beam are arranged in the casing so that the incident surface faces the end surface of the optical fiber mounted in the optical fiber mounting port, and the original laser beams emitted from the end surface of the optical fiber are first and second. A roof-type prism that divides the laser beam into
A collimating lens disposed in the casing so as to face the exit surface of the roof prism, and collimating the first and second branched laser beams from the roof prism,
The first and second on the workpiece that are disposed in the casing in proximity to the laser exit and that position the first and second branched laser beams from the collimating lens outside the casing. A condensing lens for condensing each of the processing points,
A first adjustment unit for variably adjusting the relative positional relationship between the roof prism and the end face of the optical fiber in a first direction on the optical axis of the collimating lens;
A second adjusting unit for variably adjusting the relative positional relationship between the roof prism and the output end face of the optical fiber in a second direction within a plane orthogonal to the optical axis of the collimating lens. Laser emission unit.   3. The laser emitting unit according to claim 2, wherein the second direction includes two directions orthogonal to each other within a plane orthogonal to the first direction.   4. The laser emitting unit according to claim 2, wherein the second direction includes a direction orthogonal to a ridge line of the inclined surface of the roof prism. 5.   5. The laser emission unit according to claim 2, further comprising a third adjustment unit configured to adjust a direction of the roof-type prism in a direction around the optical axis of the collimating lens. A laser oscillation unit that oscillates and outputs an original laser beam for laser processing;
The laser emission unit according to any one of claims 2 to 5,
An optical fiber for transmitting the original laser beam oscillated and output from the laser oscillation unit to the laser emission unit;
First and second branch laser beams emitted from the laser emission unit are respectively focused and irradiated on first and second machining points separated from each other by a predetermined distance on the workpiece, and laser Laser processing equipment that simultaneously performs laser processing with different energies.

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