JP2007319878A - Laser beam machining apparatus and laser beam machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus and a laser beam machining method capable of compatibly satisfying the depth of penetration and preventing any weld defect even under a condition that a deep depth of penetration is requested, and weld defects are easily generated. <P>SOLUTION: First laser beams B1 emitted from a first laser beam source 2 are formed into parallel beams by a collimate lens 3, and their angle of reflection is changed at a predetermined period by turning a rotary mirror 4 in the turning direction 8 at a predetermined period. The beams are guided to a dichroic mirror 6 by a fixed mirror 5, reflected by the dichroic mirror 6, superposed on second laser beams B2, condensed by a condensing lens 7, and irradiated on an object member 10 while being weaved in the weaving direction 9. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus and a laser processing method, and is useful when applied to, for example, thermal processing such as welding using a laser beam.

  In laser processing, a laser beam is condensed using a lens or the like to form a heat source having a high energy density, and the base material such as metal is melted by irradiating the base material such as metal with the laser beam being condensed. Processing such as welding, cutting, overlaying, and surface treatment is performed.

  For example, when welding with a laser beam (laser welding) is performed, the focused laser beam is continuously irradiated to the groove portion of the base material while moving at a constant speed. At this time, the groove portion of the base material is instantaneously melted and evaporated, and a consistent keyhole is formed from the surface to the inside of the base material by the reaction force of the evaporation. Then, a molten pool made of molten metal is formed around the keyhole, and the molten metal in the molten pool in the direction opposite to the traveling direction of the keyhole is cooled and solidified, and welding is performed.

JP 2005-111519 A JP 2003-251484 A

  As described above, in laser welding, welding is performed by moving a formed keyhole by irradiating a base material while moving a laser beam that has been condensed and increased in energy. At this time, along with the generation and movement of the keyhole, there was a problem that a bubble-like cavity called porosity (or blowhole) was left behind, resulting in a welding defect.

  Specifically, along with the movement of the laser beam, the hole formed as the keyhole also moves. However, the atmosphere gas in the keyhole is easily trapped near the tip of the keyhole, leaving a bubble-like cavity. In some cases, it solidifies in a state of welding and becomes a welding defect. In addition, as the laser beam moved, the shape of the middle part of the keyhole was not a straight shape, but a constricted shape, and the atmosphere gas in the keyhole was easily trapped, leaving a bubble-like cavity. In some cases, it solidifies in a state and becomes a welding defect. Furthermore, due to the convection of the molten metal in the molten pool, as the laser beam moves, the molten metal is covered so as to close the opening of the keyhole, and solidifies in a state where the bubble-like cavities are left behind. Sometimes it was. In this way, when laser welding is performed, if the shape of the keyhole becomes unstable, a bubble-like cavity called porosity is left behind in the metal after laser welding, which becomes a cause of welding defects. It was.

  Thus, in laser welding, a method for preventing defects (porosity) due to unstable collapse of keyholes has been demanded. As one solution to such a problem, the inventors of the present application described in Japanese Patent Application No. 2005-085319, which has already been filed, combined laser beams of a plurality of wavelengths and reduced the laser beam diameter to 1 mm or less in laser welding. By doing so, it has been confirmed that a defect suppressing effect can be obtained. However, if the laser beam diameter is made too small, the penetration depth becomes shallow, resulting in a problem that efficiency during welding is lowered. That is, there is no method for achieving both penetration depth and defect suppression, and there has been a demand for a method for preventing welding defects even at a laser beam diameter that provides deep penetration.

  Furthermore, when performing lap welding by laser welding, the shape of the keyhole becomes unstable due to another cause, leaving porosity in the metal after laser welding, resulting in welding defects. It was. The cause of this will be described with reference to FIG.

  As shown in FIG. 17 (a), when performing lap welding by laser welding, a lower plate and an upper plate that are base materials are overlapped, and a focused laser beam is applied to a groove portion of the base material. Irradiate continuously while moving the beam in the direction of the arrow at a constant speed. At this time, the groove portion of the base material is instantaneously melted and evaporated, and a consistent keyhole can be formed from the upper plate surface to the lower plate, and a molten pool made of molten metal around the keyhole. Can be formed. Therefore, with the progress of the keyhole, the molten metal in the molten pool in the direction opposite to the traveling direction of the keyhole is cooled and solidified as a weld metal, whereby the lower plate and the upper plate are welded.

  However, when lap welding is performed, there is a gap (gap) between the lower plate and the upper plate, and it is difficult to maintain the keyhole at the boundary surface of the gap, and it is easy to have a constricted shape. (See FIGS. 17A and 17B. Note that the thickness of the gap is exaggerated for ease of understanding.) Specifically, in the case of lap welding, it is impossible to completely adhere the lower plate and the upper plate. Therefore, a gap is formed between the lower plate and the upper plate, and the laser beam penetrating the upper plate is used again. The keyhole on the lower plate side to be formed is difficult to stably open, and instability of the keyhole in the vicinity of the boundary surface cannot be avoided. In such a situation, the atmosphere gas in the keyhole is likely to be entrained in the portion ahead of the constricted portion, and as a result, it solidifies in a state where the bubble-like cavities are left behind, resulting in porosity, that is, weld defects. It occurred (FIG. 17 (c)). In the case of lap welding, in particular, when the upper plate has a thickness of 2 mm or more, this welding defect is more prominent, and even with a thicker plate thickness, that is, a deeper penetration depth. There has been a demand for a method for preventing a welding defect by ensuring a penetration depth even in a situation where a welding defect is more likely to occur.

  The present invention has been made in view of the above problems, and a laser processing apparatus capable of achieving both penetration depth and prevention of welding defects even under conditions where a deep penetration depth is required and welding defects are likely to occur. An object is to provide a laser processing method.

A laser processing apparatus according to a first invention for solving the above-described problems is as follows.
A first laser light source that emits a first laser beam having one or a plurality of different wavelengths;
A second laser light source that emits a second laser beam having a shorter wavelength than the first laser beam or a plurality of wavelengths different from each other and having a condensing diameter larger than that of the first laser beam;
Superimposing means for superimposing the first laser beam and the second laser beam;
Condensing means for condensing the first laser beam and the second laser beam superimposed,
In a laser processing apparatus that performs desired laser processing by irradiating the target member with the focused first laser beam and the second laser beam,
The first laser beam under the condition that the irradiation position of the first laser beam on the target member is periodically moved in the same direction as the traveling direction in which laser processing is performed, and the periodic movement amount of the irradiation position is set so as to increase the penetration depth. First period moving means having a size of 5% to 100%, preferably 40% of the opening diameter of the keyhole formed by the beam is provided.

A laser processing apparatus according to a second invention for solving the above-mentioned problems is as follows.
In the laser processing apparatus according to the first invention,
Furthermore, at least one or more second period moving means for periodically moving the irradiation position of the first laser beam on the target member in a direction different from the period moving direction is provided.

A laser processing apparatus according to a third invention for solving the above-mentioned problem is as follows.
In the laser processing apparatus according to the first or second invention,
Furthermore, the present invention is characterized in that third period moving means is provided for periodically moving the irradiation position of the second laser beam on the target member in the same direction as the traveling direction in which laser processing is performed.

A laser processing apparatus according to a fourth invention for solving the above-mentioned problem is as follows.
In the laser processing apparatus according to the third invention,
Furthermore, at least one or more fourth period moving means for periodically moving the irradiation position of the second laser beam on the target member in a direction different from the period moving direction is provided.

A laser processing apparatus according to a fifth invention for solving the above-mentioned problem is as follows.
A first laser light source that emits a first laser beam having one or a plurality of different wavelengths;
A second laser light source that emits a second laser beam having a shorter wavelength than the first laser beam or a plurality of wavelengths different from each other and having a condensing diameter larger than that of the first laser beam;
Superimposing means for superimposing the first laser beam and the second laser beam;
Condensing means for condensing the first laser beam and the second laser beam superimposed,
In a laser processing apparatus that performs desired laser processing by irradiating the target member with the focused first laser beam and the second laser beam,
The irradiation position of the superimposed first laser beam and second laser beam on the target member is periodically moved in the same direction as the traveling direction in which laser processing is performed, and the amount of periodic movement of the irradiation position is determined by the penetration depth. The fifth period moving means is provided which has a size of 5% to 100%, preferably 40% of the opening diameter of the keyhole formed by the first laser beam under the condition of increasing .

A laser processing apparatus according to a sixth invention for solving the above-mentioned problems is as follows.
In the laser processing apparatus according to the fifth invention,
Furthermore, at least one or more sixth period moving means for periodically moving the irradiation positions of the superimposed first laser beam and second laser beam on the target member in a direction different from the period moving direction is provided. It is characterized by.

A laser processing apparatus according to a seventh invention for solving the above-mentioned problems is as follows.
In the laser processing apparatus according to the sixth invention,
A convex cylindrical body that periodically changes the reflection angle of the first laser beam and the second laser beam superimposed on the one close to the target member of the fifth period moving unit or the sixth period moving unit. It is characterized by being a cylindrical mirror using a surface.

A laser processing apparatus according to an eighth invention for solving the above-mentioned problems is as follows.
In the laser processing apparatus according to the sixth invention,
A convex toroid that periodically changes the reflection angle of the first laser beam and the second laser beam superimposed on the one close to the target member of the fifth period moving unit or the sixth period moving unit. It is a toroidal mirror using a surface.

A laser processing apparatus according to a ninth invention for solving the above-mentioned problems is as follows.
In the laser processing apparatus according to any one of the first to eighth inventions,
At least one of the first period moving means, the second period moving means, the third period moving means, the fourth period moving means, the fifth period moving means, or the sixth period moving means, The rotating mirror is configured to periodically change the reflection angle of the first laser beam, the second laser beam, or the first laser beam and the second laser beam.

A laser processing apparatus according to a tenth invention for solving the above-mentioned problem is as follows.
In the laser processing apparatus according to any one of the first to ninth inventions,
At least one of the first period moving means, the second period moving means, the third period moving means, the fourth period moving means, the fifth period moving means, or the sixth period moving means, A translation mirror that periodically translates the optical path of the first laser beam, the second laser beam, or the first laser beam and the second laser beam is used.

A laser processing apparatus according to an eleventh invention for solving the above-described problems is
In the laser processing apparatus according to any one of the first to tenth inventions,
At least one of the first period moving means, the second period moving means, the third period moving means, and the fourth period moving means is the first laser light source, the second laser light source, or the first The incident positions of the laser light source and the second laser light source are parallel moving means for periodically translating on the incident plane.

A laser processing apparatus according to a twelfth invention for solving the above-mentioned problems is
In the laser processing apparatus according to any one of the first to eleventh inventions,
The target member is a superposed member.

A laser processing method according to a thirteenth aspect of the present invention for solving the above problem is as follows:
A first laser beam having one or a plurality of different wavelengths and a second laser beam having one or a plurality of wavelengths shorter than the first laser beam and having a condensing diameter larger than that of the first laser beam. Superimposed with the laser beam,
Condensing the superimposed first and second laser beams;
In a laser processing method for performing desired laser processing by irradiating a target member with the focused first laser beam and the second laser beam,
The first laser beam under the condition that the irradiation position of the first laser beam on the target member is periodically moved in the same direction as the traveling direction in which laser processing is performed, and the periodic movement amount of the irradiation position is set so as to increase the penetration depth. The size is 5% to 100%, preferably 40%, of the diameter of the keyhole formed by the beam.

A laser processing method according to a fourteenth aspect of the present invention for solving the above problems is as follows:
In the laser processing method according to the thirteenth invention,
Furthermore, the irradiation position of the first laser beam on the target member is periodically moved in at least one direction different from the periodic movement direction.

A laser processing method according to a fifteenth aspect of the present invention for solving the above problem is as follows:
In the laser processing method according to the thirteenth or fourteenth aspect,
Furthermore, the irradiation position of the second laser beam on the target member is periodically moved in the same direction as the traveling direction in which laser processing is performed.

A laser processing method according to a sixteenth aspect of the present invention for solving the above problems is as follows.
In the laser processing method according to the fifteenth aspect,
Furthermore, the irradiation position of the second laser beam on the target member is periodically moved in at least one direction different from the periodic movement direction.

A laser processing method according to a seventeenth aspect of the present invention for solving the above problems is as follows:
A first laser beam having one or a plurality of different wavelengths and a second laser beam having one or a plurality of wavelengths shorter than the first laser beam and having a condensing diameter larger than that of the first laser beam. Superimposed with the laser beam,
Condensing the superimposed first and second laser beams;
In a laser processing method for performing desired laser processing by irradiating a target member with the focused first laser beam and the second laser beam,
The irradiation position of the superimposed first laser beam and second laser beam on the target member is periodically moved in the same direction as the traveling direction in which laser processing is performed, and the amount of periodic movement of the irradiation position is determined by the penetration depth. It is characterized in that the size is 5% to 100%, preferably 40%, of the opening diameter of the keyhole formed by the first laser beam under the condition that becomes large.

A laser processing method according to an eighteenth aspect of the present invention for solving the above problem is as follows.
In the laser processing method according to the seventeenth invention,
Further, the irradiation position of the superimposed first laser beam and second laser beam on the target member is periodically moved in one or more directions different from the periodic movement direction.

A laser processing method according to a nineteenth aspect of the present invention for solving the above problem is as follows.
In the laser processing method according to the eighteenth aspect of the invention,
The periodic movement is performed by periodically changing a reflection angle of the superimposed first laser beam and the second laser beam using a cylindrical mirror having a convex cylindrical surface as a mirror closer to the target member. It is characterized by performing.

A laser processing method according to a twentieth invention for solving the above problems,
In the laser processing method according to the eighteenth aspect of the invention,
In the periodic movement, a toroidal mirror having a convex toroidal surface is used as a mirror closer to the target member, and the reflection angles of the superimposed first laser beam and second laser beam are periodically changed. It is characterized by performing.

A laser processing method according to a twenty-first aspect of the present invention for solving the above problem is as follows:
In the laser processing method according to any one of the thirteenth to twentieth inventions,
The periodic movement is performed by periodically changing a reflection angle of the first laser beam, the second laser beam, or the first laser beam and the second laser beam using a rotating mirror. And

A laser processing method according to a twenty-second aspect of the present invention for solving the above problem is as follows:
In the laser processing method according to any one of the thirteenth to twenty-first aspects,
The periodic movement is performed by periodically translating the first laser beam, the second laser beam, or the optical path of the first laser beam and the second laser beam using a translation mirror. Features.

A laser processing method according to a twenty-third invention for solving the above-mentioned problems is as follows.
In the laser processing method according to any one of the thirteenth to twenty-second inventions,
The periodic movement is performed by periodically translating the incident positions of the first laser light source, the second laser light source, or the first laser light source and the second laser light source on an incident plane. And

A laser processing method according to a twenty-fourth aspect of the present invention for solving the above problems is as follows:
In the laser processing method according to any one of the thirteenth to twenty-third inventions,
The target member is a superposed member.

  According to the present invention, at least the first laser beam that forms the keyhole is irradiated in the same direction as the laser processing progressing direction with a predetermined period and a predetermined amount while being oscillated, so that a welding defect is likely to occur. For example, even when lap welding or the like is performed, welding defects caused by unstable collapse of the keyhole can be prevented by enlarging the substantial keyhole diameter, and a large penetration depth is ensured. In addition, the occurrence of welding defects can be suppressed.

  Hereinafter, some embodiments of a laser processing apparatus and a laser processing method according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view showing an example of an embodiment of a laser processing apparatus according to the present invention. In the laser processing apparatus according to the present invention, the configuration of the actual optical system is complicated, but the configuration is also included in the drawings showing other embodiments described later, including FIG. 1 showing this embodiment. It is simplified and schematically illustrated.

  As shown in FIG. 1, the laser processing apparatus 1 of the present embodiment has a first laser light source 2 that emits a first laser beam B1 having one or a plurality of different wavelengths as an optical system of the first laser beam B1. And the collimating lens 3 that makes the emitted first laser beam B1 a parallel beam, the first laser beam B1 is reflected, and the rotation angle is changed at a predetermined cycle by a motor or the like (not shown). A rotating mirror 4 (first period moving means) that changes the reflection angle of B1 at a predetermined period, a fixed mirror 5 that reflects the first laser beam B1, and a second laser beam that will be described later while reflecting the first laser beam B1. A dichroic mirror 6 (superimposing means) that transmits B2 and superimposes the first laser beam B1 and the second laser beam B2, and a first laser beam B that is a parallel beam. And a condensing lens 7 (condensing means) for condensing the.

  Further, the laser processing apparatus 1 of the present embodiment emits a second laser beam B2 having a wavelength different from that of the first laser beam B1 and having one or a plurality of different wavelengths as an optical system of the second laser beam B2. A second laser light source 11 for collimating, a collimating lens 12 for collimating the emitted second laser beam B2, a dichroic mirror 6 for transmitting the second laser beam B2 and reflecting the first laser beam B1. A condensing lens 7 is provided for condensing the second laser beam B2 of the light beam.

  Therefore, the first laser beam B1 emitted from the first laser light source 2 is converted into a parallel light beam by the collimating lens 3, and the reflection angle is set at a predetermined cycle by rotating the rotary mirror 4 in the rotation direction 8 at a predetermined cycle. When it is changed and guided to the dichroic mirror 6 side by the fixed mirror 5 and reflected by the dichroic mirror 6, it is superimposed on the second laser beam B2. The second laser beam B2 emitted from the second laser light source 11 is converted into a parallel light beam by the collimating lens 12, and is superimposed on the first laser beam B1 when passing through the dichroic mirror 6. Then, the superposed first laser beam B1 and second laser beam B2 are collected by the condenser lens 7, and the first laser beam B1 is weaved (periodically moved) in the weaving direction 9 at a predetermined period, and the target member. 10 is irradiated to perform desired laser processing.

  The first laser light source 2 is composed of, for example, one or a plurality of YAG lasers, fiber lasers, or the like, and is connected to the laser processing apparatus 1 directly or indirectly via an optical fiber or the like. The second laser light source 11 is composed of, for example, one or a plurality of semiconductor lasers (laser diodes or the like), and is also connected directly or indirectly to the laser processing apparatus 1 via an optical fiber or the like. Has been.

  The first laser beam B1 emitted from the first laser light source 2 is a central beam of the laser processing apparatus 1, and is irradiated to form a needle-like keyhole so as to promote melting. The second laser beam B2 emitted from the second laser light source 11 is irradiated mainly for stabilization of the molten pool. For example, the first laser beam B1 has a wavelength of 1070 nm, and the second laser beam B2 has a wavelength shorter than the first laser beam B1, for example, a plurality of wavelengths such as 808 nm, 940 nm, and 980 nm. It is said.

  Further, the collimating lenses 3 and 12 can move their positions along the optical axis of the first laser beam B1 and the optical axis of the second laser beam B2 so that the zoom operation can be independently performed. The condensing lens 7 also adjusts the optical axis of the first laser beam B1 and the second laser beam so that the condensing diameter of the first laser beam B1 and the condensing diameter of the second laser beam B2 can be adjusted to desired sizes. The position is movable along the optical axis of B2. In the present invention, the condensing diameter of the second laser beam B2 on the target member 10 is preferably relatively larger than the condensing diameter of the first laser beam B1 on the target member 10, and such a state is obtained. The optical systems such as the collimating lenses 3 and 12 and the condenser lens 7 are appropriately set.

  The dichroic mirror 6 has a transmission / reflection characteristic of reflecting the first laser beam B1 and transmitting the second laser beam B2 in order to superimpose the first laser beam B1 and the second laser beam B2. It is desirable that the change of the transition region of the reflection characteristic is steep.

  Although not shown, the laser processing apparatus 1 is provided with a shield gas supply device for supplying a shield gas such as argon around the target member 10 where the keyhole and the molten pool are formed. In this case, oxidation of the target member 10 is prevented.

  Also, although not shown in the figure, there is also provided a drive device that can move the relative position of the laser processing apparatus 1 and the target member 10, and by moving the relative position according to the shape of the target member 10, The irradiation positions of the first laser beam B1 and the second laser beam B2 are moved to arbitrary positions, and the traveling direction of the laser processing is controlled so that a desired position of the target member can be welded.

  In this embodiment, the traveling direction of the first laser beam B1 and the second laser beam B2, that is, the traveling direction of laser processing is controlled by controlling the driving device. The weaving operation is performed in a straight line (one-dimensional direction) on the irradiation position of the first laser beam B1 on the target member 10 in the same direction as the direction of laser processing.

  Here, the weaving operation of the first laser beam B1 will be described with reference to FIG. In FIG. 2, the solid line indicates the focused diameter of the first laser beam B1 on the target member 10, and the dotted line indicates the focused diameter of the second laser beam B2 on the target member 10. In FIG. 2, the upward direction is the direction of laser processing.

  As shown in FIG. 2, the focused diameter of the second laser beam B2 is set to be larger than the focused diameter of the first laser beam B1 on the surface of the target member 10, for example, the first laser beam B1. The condensing diameter of the second laser beam B2 is about 750 μm.

  Then, the first laser beam B1 and the second laser beam B2 are irradiated at the reference position (see 0 ° in FIG. 2) with the central position of their condensed diameters being coaxial, and the first laser beam B1 is The irradiation position is weaved using the center position as the center position of the weaving operation.

  Specifically, by rotating the rotating mirror 4 in the laser processing apparatus 1 shown in FIG. 1 in the rotation direction 8 at a predetermined cycle, the irradiation position of the first laser beam B1 is changed in the vertical direction in FIG. The weaving operation is performed in (weaving direction 9). For example, when the rotating mirror 4 is rotated in a predetermined cycle and the angle is within a range of ± 1 °, the irradiation position of the first laser beam B1 is changed according to the rotating angle of the rotating mirror 4 as shown in FIG. As it moves, its irradiation shape changes. For example, at 0 °, the beam shape of the first laser beam B1 is a circular shape concentric with the beam shape of the second laser beam B2, but as the angle increases to ± 0.5 ° and ± 1 °, the beam The shape is an ellipse shape long in the weaving direction 9.

According to the knowledge of the inventors of the present application, as shown in the upper graph of FIG. 3, when the weaving amount of the first laser beam B1 is changed with respect to the opening diameter of the formed keyhole, the generation of porosity is caused. With respect to the number, the generated number can be reduced to 0 if the amount is not less than a predetermined weaving amount (the optimum value under the following conditions is 40%) with respect to the opening diameter of the formed keyhole. This is a condition that defines a lower limit value of the weaving amount, and is set to an appropriate condition according to the type of the target member 10, the progress of welding, the required penetration depth, and the like, and the minimum value is 5 %.
On the other hand, as shown in the lower graph of FIG. 3, when the weaving amount of the first laser beam B1 is changed with respect to the opening diameter of the formed keyhole, the penetration depth formed by the laser beam is as follows. The depth of penetration is only slightly reduced until the predetermined weaving amount (40%) with respect to the opening diameter of the formed keyhole, and from the predetermined weaving amount (40%) to 100%, When the penetration depth is gradually reduced and the weaving amount exceeds 100%, the penetration depth is greatly reduced, and it becomes difficult to obtain a desired penetration depth. This is a condition that defines the upper limit of the weaving amount.
In other words, in order to achieve both suppression of porosity generation and a desired penetration depth, the weaving amount of the first laser beam B1 is set under conditions that increase the penetration depth when the weaving is stopped (for example, laser beam output, concentration). The diameter of the opening of the keyhole formed by the first laser beam B1 (light diameter, etc.) is 5% to 100%, preferably about 40%. This is the same in other embodiments described later. Therefore, conditions such as the output of the first laser beam B1, the focused diameter, etc. are set so that the depth of penetration by the first laser beam B1 is as large as possible, and the opening diameter of the generated keyhole is set to 40. What is necessary is just to set the weaving amount of 1st laser beam B1 so that it may become about%. The weaving period (frequency) of the first laser beam B1 is also set to an appropriate condition according to the type of the target member 10, the welding speed, the required penetration depth, and the like. For example, when the target member 10 is stainless steel and the welding speed is 0.4 m / min, the weaving frequency is about 60 Hz to 100 Hz and the weaving amount is about 0.5 mm.

Next, actions and effects associated with the weaving operation will be described with reference to FIG.
As shown in FIG. 4A, when the lower plate 10a and the upper plate 10b, which are target members, are overlap-welded, the gap 10c generated between the lower plate 10a and the upper plate 10b cannot be avoided. Also here, for the sake of easy understanding, the thickness of the gap 10c is greatly exaggerated.

  When welding the target member 10, welding is performed while moving the first laser beam B <b> 1 and the second laser beam B <b> 2 in the welding traveling direction 13. At this time, the first laser beam B1 and the second laser beam B2 are irradiated from the upper side of the upper plate 10b to form the keyhole 14 by the first laser beam B1, and the keyhole 14 is formed by the second laser beam B2. A molten pool 16 is formed around the periphery. In the present embodiment, the first laser beam B1 is weaving at a predetermined cycle in the weaving direction 9 that is the same as the traveling direction 13, so that the keyhole 14 indicated by the solid line in FIG. The substantial diameter of the keyhole 14 can be enlarged and the opening can be stably performed. For reference, a state without weaving is shown as a dotted keyhole 15.

  This situation will be described in more detail. For example, as shown in FIG. 4B, at the moment when the first laser beam B1a is irradiated with the progress of welding, the bubble 17 similar to the conventional one is formed in the keyhole 15a. 4b, as shown in FIG. 4 (c), at the next moment, the keyhole 15b moves rearward together with the irradiation of the first laser beam B1b moved rearward by the weaving operation. Thus, the formed bubbles 17 are absorbed by the keyhole 15b. That is, the bubble 17 is forcibly absorbed (excluded) by the keyhole moved by the weaving operation so that the bubble 17 does not remain behind in the traveling direction 13. In particular, as described above, in the lap welding, due to the presence of the gap 10c, the keyhole becomes unstable in the vicinity thereof, and the bubbles 17 remain, often resulting in porosity. By weaving the first laser beam B1, bubbles can be prevented from remaining, and as a result, generation of porosity can be prevented.

  FIG. 5 is a cross-sectional photograph in which the formation of keyholes during welding is observed with X-rays over time in order to actually confirm the situation of FIG. Note that (1) → (2) → (3) is performed by the conventional method, and (4) → (5) → (6) is performed by the method of the present invention. These welding conditions are: total laser power (sum of outputs of the first laser beam B1 and the second laser beam B2) is 5 kW, the welding speed is 0.4 m / min, and the target member is a single flat plate stainless steel. (SUS304), the shielding gas is argon (Ar), the weaving conditions are 60 Hz, the amount is 0.5 mm, and welding is performed under the same conditions except for the presence or absence of weaving.

  As shown in (1) → (2) → (3) of FIG. 5, in the conventional method, bubbles are formed along with the progression of the keyhole during welding (progress of welding) and on the rear side in the traveling direction. You can see how it remains and becomes porosity. On the other hand, in the method of the present invention, as shown in FIG. 5 (4) → (5) → (6), bubbles are formed at a certain moment as the keyhole advances during welding. However, at the next moment, the bubbles left behind in the traveling direction are absorbed again by the keyhole moved backward by the weaving and do not remain as bubbles, and it can be seen that the generation of porosity can be prevented.

  In order to confirm the effect of the present invention in lap welding, FIG. 6 shows an inspection of internal defects using X-rays or the like by radiation transmission (RT) inspection. Again, a comparison is made with the conventional method. The welding conditions here are 4 kW in total laser power, 4 m / min of the welding progress speed, and the target member is a stack of two aluminum (A6061) flat plates with a thickness of 2 mm. The frequency is 80 Hz, the rotation angle of the rotating mirror 4 is ± 0.6 °, and welding is performed under the same conditions except for the presence or absence of weaving.

  As can be seen from the cross-sectional macro (1) and the RT inspection result (2) shown in FIG. 6, in the conventional welding, a large number of porosity is formed. In particular, in the conventional method, when the upper plate has a thickness of 2 mm or more, it occurs more remarkably. On the other hand, as can be seen from the cross-sectional macro (3) and the RT inspection result (4) shown in FIG. 6, it can be seen that no porosity is generated in the method of the present invention, confirming the effectiveness of the present invention. did it. In addition, the RT inspection result (4) shown in FIG. 6 is attached with a dotted line so that the welded portion can be seen.

  Thus, in the present invention, by performing laser processing under the control as described above, the substantial keyhole diameter can be enlarged while maintaining the penetration depth, and as a result, the keyhole It is possible to prevent the occurrence of welding defects due to residual porosity. In addition, the present invention is particularly useful when the target member is a superposed member (for example, the lower plate 10a and the upper plate 10b shown in FIG. 4).

  In the present embodiment, the weaving direction 9 of the first laser beam B1 is the same direction as the laser processing advance direction 13, but is further predetermined in at least one direction different from the laser processing advance direction 13. A period and a predetermined amount of weaving operation may be added (second period moving means). For example, the weaving operation of the first laser beam B1 may be performed in a two-dimensional direction by changing the fixed mirror 5 to a rotating mirror having a rotation axis in a direction different from that of the rotating mirror 4. In this case, although the control becomes complicated, the weaving trajectory of the first laser beam B1 can be circular or elliptical. Accordingly, the irradiation position of the first laser beam B1 on the target member 10 can be weaved in an arbitrary direction with respect to the progress direction of the laser processing, and the laser processing with a complicated shape can be dealt with.

  FIG. 7 is a schematic view showing another example of the embodiment of the laser processing apparatus according to the present invention. In FIG. 7, the same components as those of the laser processing apparatus shown in the above embodiment are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 7, in the laser processing apparatus 21 of the present embodiment, the optical system of the second laser beam B2 has the same configuration as that of the first embodiment (FIG. 1), but the optical system of the first laser beam B1. The first laser light source 2 that emits the first laser beam B1, the collimator lens 3 that makes the emitted first laser beam B1 a parallel beam, the first laser beam B1 and a moving device (not shown) By parallel translation (sliding) with a predetermined period by, for example, a parallel movement mirror 22 (first period moving means) that translates the optical path of the first laser beam B1 with a predetermined period, and a fixed that reflects the first laser beam B1. A mirror 5, a dichroic mirror 6 that reflects the first laser beam B 1 and transmits the second laser beam B 2, and a condensing lens 7 that condenses the first laser beam B 1 of parallel rays. It is.

  Accordingly, the first laser beam B1 emitted from the first laser light source 2 is converted into a parallel light beam by the collimating lens 3, and the optical path is changed at a predetermined period by translating the translation mirror 22 in the translation direction 23 at a predetermined period. When translated, guided to the dichroic mirror 6 side by the fixed mirror 5, and reflected by the dichroic mirror 6, it is superimposed on the second laser beam B2. Then, the superimposed first laser beam B1 and second laser beam B2 are collected by the condenser lens 7, and the first laser beam B1 is weaved (periodically moved) in the weaving direction 24 at a predetermined cycle, while the target member is 10 is irradiated to perform desired laser processing.

  Similar to the first embodiment, in this embodiment, the driving direction of the first laser beam B1 and the second laser beam B2, that is, the laser processing progress direction is controlled by controlling the driving device. The weaving direction 24 is set to the same direction as the laser processing progressing direction, and the irradiation position of the first laser beam B1 on the target member 10 is linearly (one-dimensional direction).

  The weaving direction 24 of the first laser beam B1 may be the same direction as the laser processing progress direction, but further, at least one direction different from the laser processing progress direction in a predetermined period and a predetermined amount of weaving operation. May be added (second period moving means). For example, by providing another translation mirror that translates in a direction different from the translation mirror 22 (for example, a direction perpendicular to the translation direction 23), the weaving direction of the first laser beam B1 is set in a two-dimensional direction (eg, , Circular or elliptical). This makes it possible to weave the irradiation position of the first laser beam B1 on the target member 10 in an arbitrary direction with respect to the direction of laser processing, and it is possible to cope with laser processing of a complicated shape.

  FIG. 8 is a schematic view showing another example of the embodiment of the laser processing apparatus according to the present invention. In FIG. 8 as well, the same components as those of the laser processing apparatus shown in the above embodiment are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 8, in the laser processing apparatus 31 of the present embodiment, the optical system of the second laser beam B2 has the same configuration as that of the first embodiment (FIG. 1), but the optical system of the first laser beam B1. And a first laser light source 32 having parallel movement means (first period movement means) that emits the first laser beam B1 and translates the incident position on the incident plane in a predetermined cycle, and the emitted first laser beam B1. A collimating lens 3 that converts the laser beam B1 into parallel rays, a fixed mirror 33 that reflects the first laser beam B1, a fixed mirror 5 that reflects the first laser beam B1, and a second laser beam that reflects the first laser beam B1. A dichroic mirror 6 that transmits the laser beam B2 and a condensing lens 7 that condenses the parallel first laser beam B1 are provided. For example, when moving the incident position of the first laser beam B1, if the first laser light source 32 is connected to the laser processing apparatus 31 using an optical fiber, the connection position of the optical fiber is set in the parallel movement direction 34. Just move. The configuration of the laser light source portion of the first laser light source 32 may be the same as that of the first laser light source 2 described in the first embodiment.

  Therefore, the optical path of the first laser beam B1 emitted from the first laser light source 32 is translated in a predetermined cycle by translating the incident position in the parallel movement direction 34 in a predetermined cycle. When the light is guided to the dichroic mirror 6 side by the fixed mirror 33 and the fixed mirror 5 and reflected by the dichroic mirror 6, it is superimposed on the second laser beam B2. Then, the superimposed first laser beam B1 and second laser beam B2 are collected by the condenser lens 7, and the target member 10 is irradiated while the first laser beam B1 is weaved in the weaving direction 35 at a predetermined period. Thus, desired laser processing is performed.

  Similar to the first embodiment, in this embodiment, the driving direction of the first laser beam B1 and the second laser beam B2, that is, the laser processing progress direction is controlled by controlling the driving device. The weaving direction 35 is set to the same direction as the laser processing progressing direction, and the irradiation position of the first laser beam B1 on the target member 10 is linearly (one-dimensional direction).

  Note that the weaving direction 35 of the first laser beam B1 may be the same direction as the laser processing progress direction, but further, at least one direction different from the laser processing progress direction in a predetermined period and a predetermined amount of weaving operation. May be added (second period moving means). For example, by moving the incident position of the first laser beam B1 in a direction different from the translation direction 34 (for example, a direction perpendicular to the translation direction 34), the weaving direction of the first laser beam B1 is changed to a two-dimensional direction ( For example, the weaving operation may be performed in a circular or elliptical shape. Accordingly, the irradiation position of the first laser beam B1 on the target member 10 can be weaved in an arbitrary direction with respect to the progress direction of the laser processing, and the laser processing with a complicated shape can be dealt with.

  FIG. 9 is a schematic view showing another example of the embodiment of the laser processing apparatus according to the present invention, and corresponds to a modification of Example 1 (FIG. 1). In FIG. 9 as well, the same components as those of the laser processing apparatus shown in the above embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The laser processing apparatus 41 of the present embodiment is configured to weave only the first laser beam B1 in the laser processing apparatus 1 shown in the embodiment 1 (FIG. 1), but the second laser beam B2 is also used. It has a configuration for weaving.

  Specifically, in the laser processing apparatus 41 of the present embodiment, the optical system of the first laser beam B1 has the same configuration as that of the first embodiment (FIG. 1), but the wavelength is different from that of the first laser beam B1. As an optical system of the second laser beam B2, a second laser light source 11 that emits the second laser beam B2, a collimator lens 12 that makes the emitted second laser beam B2 a parallel beam, and the second laser beam B2 are reflected. At the same time, the rotation angle is changed at a predetermined cycle by a motor or the like (not shown) to change the reflection angle of the second laser beam B2 at a predetermined cycle, and the second laser beam B2. Includes a dichroic mirror 6 that transmits and reflects the first laser beam B1, and a condenser lens 7 that condenses the second laser beam B2 of parallel rays.

  Therefore, the second laser beam B2 emitted from the second laser light source 11 is converted into a parallel light beam by the collimating lens 12, and the reflection angle is set to a predetermined cycle by rotating the rotating mirror 42 in the rotation direction 43 at a predetermined cycle. When it is changed and transmitted through the dichroic mirror 6, it is superimposed on the first laser beam B1. Then, the superimposed first laser beam B1 and second laser beam B2 are collected by the condenser lens 7, and the first laser beam B1 is in the weaving direction 9 and the second laser beam B2 is in the weaving direction 44. The target member 10 is irradiated while being weaved at a predetermined period, and desired laser processing is performed. That is, the laser processing apparatus 41 of the present embodiment has a configuration in which each of the optical system of the first laser beam B1 and the optical system of the second laser beam B2 has a weaving function.

  Similar to the first embodiment, in this embodiment, the driving direction of the first laser beam B1 and the second laser beam B2, that is, the laser processing progress direction is controlled by controlling the driving device. The weaving directions 9 and 44 are set to the same direction as the laser processing progressing direction, and the irradiation positions of the first laser beam B1 and the second laser beam B2 on the target member 10 are linearly (one-dimensional direction) weaving operation. . Further, it is desirable that the second laser beam B2 performs a weaving operation in synchronization with the weaving of the first laser beam B1, and the weaving amount of the second laser beam B2 is an amount proportional to the weaving amount of the first laser beam B1. Yes.

  Note that the weaving direction 44 of the second laser beam B2 may be the same direction as the laser processing progress direction, but further, at least one direction different from the laser processing progress direction in a predetermined period and a predetermined amount of weaving operation. May be added (fourth period moving means). For example, by adding a rotating mirror having a rotation axis in a direction different from that of the rotating mirror 42, the weaving direction of the second laser beam B2 may be weaved in a two-dimensional direction (for example, circular or elliptical). Good. This makes it possible to weave the irradiation positions of the first laser beam B1 and the second laser beam B2 on the target member 10 in an arbitrary direction with respect to the direction of laser processing, and cope with laser processing of a complicated shape. Can do.

  FIG. 10 is a schematic diagram showing another example of the embodiment of the laser processing apparatus according to the present invention, and corresponds to a modification of Example 2 (FIG. 7). In FIG. 10 as well, the same components as those of the laser processing apparatus shown in the above embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The laser processing apparatus 51 of the present embodiment is configured to weave only the first laser beam B1 in the laser processing apparatus 21 shown in the embodiment 2 (FIG. 7), but the second laser beam B2 is also used. It has a configuration for weaving.

  Specifically, in the laser processing apparatus 51 of the present embodiment, the optical system of the first laser beam B1 has the same configuration as that of the first embodiment (FIG. 1), but the wavelength is different from that of the first laser beam B1. As an optical system of the second laser beam B2, a second laser light source 11 that emits the second laser beam B2, a collimator lens 12 that makes the emitted second laser beam B2 a parallel beam, and the second laser beam B2 are reflected. At the same time, a translation mirror 52 (third period movement means) that translates the optical path of the second laser beam B2 in a predetermined cycle by moving (sliding) in a predetermined cycle by a moving device (not shown) and the like, The laser beam B2 is transmitted, and includes a dichroic mirror 6 that reflects the first laser beam B1, and a condenser lens 7 that condenses the parallel second laser beam B2.

  Accordingly, the second laser beam B2 emitted from the second laser light source 11 is converted into a parallel light beam by the collimating lens 12, and the optical path is changed at a predetermined cycle by moving the parallel movement mirror 52 in the parallel movement direction 53 at a predetermined cycle. When translated and transmitted through the dichroic mirror 6, it is superimposed on the first laser beam B1. Then, the superimposed first laser beam B1 and second laser beam B2 are condensed by the condenser lens 7, and the first laser beam B1 is in the weaving direction 24 and the second laser beam B2 is in the weaving direction 54. The target member 10 is irradiated while being weaved at a predetermined period, and desired laser processing is performed. That is, the laser processing apparatus 51 of the present embodiment has a configuration in which each of the optical system of the first laser beam B1 and the optical system of the second laser beam B2 has a weaving function.

  Similar to the first embodiment, in this embodiment, the driving direction of the first laser beam B1 and the second laser beam B2, that is, the laser processing progress direction is controlled by controlling the driving device. The weaving directions 24 and 54 are set to the same direction as the laser processing progression direction, and the irradiation positions of the first laser beam B1 and the second laser beam B2 on the target member 10 are linearly (one-dimensional direction). . Further, it is desirable that the second laser beam B2 performs a weaving operation in synchronization with the weaving of the first laser beam B1, and the weaving amount of the second laser beam B2 is an amount proportional to the weaving amount of the first laser beam B1. Yes.

  The weaving direction 54 of the second laser beam B2 may be the same direction as the laser processing progress direction, but in addition, at least one direction different from the laser processing progress direction in a predetermined period and a predetermined amount of weaving operation. May be added (fourth period moving means). For example, by providing another translation mirror that translates in a direction different from the translation mirror 52 (for example, a direction perpendicular to the translation direction 53), the weaving direction of the second laser beam B2 is changed to a two-dimensional direction (eg, , Circular or elliptical). As a result, the irradiation positions of the first laser beam B1 and the second laser beam B2 on the target member 10 can be weaved in an arbitrary direction with respect to the progress direction of the laser processing, and it is possible to cope with processing of complicated shapes. it can.

  FIG. 11 is a schematic diagram showing another example of the embodiment of the laser processing apparatus according to the present invention, and corresponds to a modification of Example 3 (FIG. 8). In FIG. 11 as well, the same components as those of the laser processing apparatus shown in the above embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The laser processing apparatus 61 of the present embodiment is configured to weave only the first laser beam B1 in the laser processing apparatus 31 shown in the embodiment 3 (FIG. 8), but the second laser beam B2 is also used. It has a configuration for weaving.

  Specifically, in the laser processing apparatus 61 of the present embodiment, the optical system of the first laser beam B1 has the same configuration as that of the first embodiment (FIG. 1), but the wavelength is different from that of the first laser beam B1. As an optical system for the second laser beam B2, a second laser light source having a parallel moving means (third periodic moving means) that emits the second laser beam B2 and translates the incident position on the incident plane in a predetermined cycle. 62, a collimating lens 12 that converts the emitted second laser beam B2 into parallel rays, a dichroic mirror 6 that transmits the second laser beam B2 and reflects the first laser beam B1, and a parallel second laser beam. It has the condensing lens 7 which condenses B2. For example, when moving the incident position of the second laser beam B2, if the second laser light source 62 is connected to the laser processing apparatus 61 using an optical fiber, the connection position of the optical fiber is set to the parallel movement direction 63. Just move. The configuration of the laser light source portion of the second laser light source 62 may be the same as that of the second laser light source 11 described in the first embodiment.

  Accordingly, the optical path of the second laser beam B2 emitted from the second laser light source 62 is weaved by translating the incident position in the parallel movement direction 63 at a predetermined period, and is converted into parallel rays by the collimator lens 12. The light passes through the mirror 6 and is superimposed on the first laser beam B1. Then, the superimposed first laser beam B1 and second laser beam B2 are collected by the condenser lens 7, the first laser beam B1 is in the weaving direction 35, and the second laser beam B2 is in the weaving direction 64. The target member 10 is irradiated while being weaved at a predetermined period, and desired laser processing is performed. That is, the laser processing apparatus 61 of the present embodiment is configured to have a weaving function in each of the optical system of the first laser beam B1 and the optical system of the second laser beam B2.

  Similar to the first embodiment, in this embodiment, the driving direction of the first laser beam B1 and the second laser beam B2, that is, the laser processing progress direction is controlled by controlling the driving device. The weaving directions 35 and 64 are set to the same direction as the laser processing progressing direction, and the irradiation positions of the first laser beam B1 and the second laser beam B2 on the target member 10 are linearly (one-dimensional direction). . Further, it is desirable that the second laser beam B2 performs a weaving operation in synchronization with the weaving of the first laser beam B1, and the weaving amount of the second laser beam B2 is an amount proportional to the weaving amount of the first laser beam B1. Yes.

  Note that the weaving direction 64 of the second laser beam B2 may be the same direction as the laser processing progress direction, but further, at least one direction different from the laser processing progress direction in a predetermined period and a predetermined amount of weaving operation. May be added (fourth period moving means). For example, by moving the emission position of the second laser beam B2 in a direction different from the translation direction 63 (for example, a direction perpendicular to the translation direction 63), the weaving direction of the second laser beam B2 is changed to a two-dimensional direction ( For example, the weaving operation may be performed in a circular or elliptical shape. As a result, the irradiation positions of the first laser beam B1 and the second laser beam B2 on the target member 10 can be weaved in an arbitrary direction with respect to the progress direction of the laser processing, and it is possible to cope with processing of complicated shapes. it can.

  FIG. 12 is a schematic view showing another example of the embodiment of the laser processing apparatus according to the present invention, and corresponds to a modification of Example 4 (FIG. 9). In FIG. 12 as well, the same components as those of the laser processing apparatus shown in the above embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The laser processing apparatus 71 of the present embodiment is configured to weave the first laser beam B1 and the second laser beam B2 in the uniaxial direction in the laser processing apparatus 41 shown in the fourth embodiment (FIG. 9). Thus, the first laser beam B1 and the second laser beam B2 are configured to perform a weaving operation independently in two axial directions. In this embodiment, each optical system (the optical system of the first laser beam B1 and the optical system of the second laser beam B2) is provided with two rotating mirrors, but more rotating mirrors are provided. However, the weaving operation according to the present invention is possible.

  Specifically, as shown in FIG. 12, the laser processing apparatus 71 of the present embodiment was emitted as a first laser light source 2 that emits the first laser beam B1 as an optical system of the first laser beam B1. A collimating lens (not shown) that makes the first laser beam B1 a parallel beam, the first laser beam B1 is reflected, and the rotation angle is changed at a predetermined period by a motor or the like (not shown) to thereby change the first laser beam B1. The rotation mirror 4 that changes the reflection angle at a predetermined cycle, reflects the first laser beam B1, transmits the second laser beam B2, and sets the rotation angle in a direction different from the rotation mirror 4 by a motor (not shown) or the like. A rotating dichroic mirror 72 that changes the reflection angle of the first laser beam B1 by a predetermined period by changing the period, and a first laser beam of parallel rays 1 has a condenser lens 7 for condensing the. The rotating dichroic mirror 72 may be the same as the dichroic mirror 6 described in the first embodiment, except that it can rotate.

  Further, the laser processing apparatus 71 of the present embodiment was emitted with the second laser light source 11 that emits the second laser beam B2 as an optical system of the second laser beam B2 having a wavelength different from that of the first laser beam B1. A collimating lens (not shown) that makes the second laser beam B2 a parallel beam and the second laser beam B2 are reflected, and the rotation angle is changed at a predetermined cycle by a motor (not shown) or the like, so that the second laser beam B2 The second rotation mirror 42 that changes the reflection angle at a predetermined cycle and the second laser beam B2 are reflected, and the rotation angle is changed at a predetermined cycle by a motor or the like (not shown) in a direction different from the rotation mirror 42. A rotating mirror 74 that changes the reflection angle of the laser beam B2 at a predetermined cycle, the second laser beam B2 is transmitted, and the first laser beam B1 is reflected. That a rotating dichroic mirror 72, and a condensing lens 7 for condensing the second laser beam B2 of parallel rays.

  Therefore, the first laser beam B1 emitted from the first laser light source 2 is converted into a parallel light beam by the collimating lens, and the reflection angle is changed at a predetermined cycle by rotating the rotating mirror 4 in the rotation direction 8 at a predetermined cycle. Further, by rotating the rotating dichroic mirror 72 in the rotating direction 73 at a predetermined cycle, the reflection angle is changed and reflected at a predetermined cycle, and the rotating dichroic mirror 72 transmits the rotating dichroic mirror 72. Superimposed on the second laser beam B2. The second laser beam B2 emitted from the second laser light source 11 is converted into a parallel light beam by the collimating lens, and the reflection angle is changed at a predetermined cycle by rotating the rotating mirror 42 in the rotation direction 43 at a predetermined cycle. Then, by rotating the rotating mirror 74 in the rotating direction 75 at a predetermined cycle, the reflection angle is changed at a predetermined cycle, transmitted through the rotating dichroic mirror 72, and superimposed on the first laser beam B1. Then, the superimposed first laser beam B1 and second laser beam B2 are condensed by the condensing lens 7, and are irradiated onto the target member 10 while being weaved in a predetermined direction at a predetermined cycle, thereby performing desired laser processing. It will be. That is, the laser processing apparatus 71 of the present embodiment has a configuration in which each of the optical system of the first laser beam B1 and the optical system of the second laser beam B2 has a weaving function that can rotate about a plurality of axes.

  Note that either the rotating mirror 4 or the rotating dichroic mirror 72 is for weaving the irradiation position of the superimposed first laser beam B1 on the target member 10 in the same direction as the traveling direction in which laser processing is performed. desirable. Further, it is desirable that the first laser beam B1 and the second laser beam B2 perform a weaving operation in synchronization.

  In the case of the laser processing apparatus 71 of the present embodiment, it is necessary to control the mirrors of the two optical systems independently, but the size of the rotating dichroic mirror 72 serving as the final stage rotating mirror can be made relatively small. it can.

  FIG. 14 is a schematic view showing another example of the embodiment of the laser processing apparatus according to the present invention. In FIG. 14 as well, the same components as those of the laser processing apparatus shown in the above embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The laser processing apparatus 81 of the present embodiment simultaneously superimposes the first laser beam B1 and the second laser beam B2 by the plurality of rotating mirrors 82 and 83 after superimposing the first laser beam B1 and the second laser beam B2. The weaving operation is performed. In this embodiment, two rotating mirrors are provided. However, at least one rotating mirror is sufficient, and the weaving operation according to the present invention can be performed even if three or more rotating mirrors are used.

  Specifically, as shown in FIG. 14, the laser processing apparatus 81 of the present embodiment emits the first laser light source 2 that emits the first laser beam B1 as an optical system of only the first laser beam B1, and is emitted. The collimating lens 3 that makes the first laser beam B1 a parallel beam and the fixed mirror 5 that reflects the first laser beam B1, and only the second laser beam B2 having a wavelength different from that of the first laser beam B1. The optical system includes a second laser light source 11 that emits a second laser beam B2, and a collimator lens 12 that makes the emitted second laser beam B2 a parallel beam.

  Further, the laser processing apparatus 81 of the present embodiment includes a dichroic mirror 6 that reflects the first laser beam B1 and transmits the second laser beam B2 as an optical system common to the first laser beam B1 and the second laser beam B2. The first laser beam B1 and the second laser beam B2 superimposed on the dichroic mirror 6 are reflected, and the rotation angle is changed at a predetermined period by a motor or the like (not shown), whereby the first laser beam B1 and the second laser beam are reflected. A rotating mirror 82 (fifth period moving means) that changes the reflection angle of B2 at a predetermined period, and reflects the superimposed first laser beam B1 and second laser beam B2, and in a direction different from the rotating mirror 82, The first laser beam B1 and the second laser beam are changed by changing the rotation angle at a predetermined cycle by a motor (not shown). A rotating mirror 83 for changing the reflection angle of the beam B2 at a predetermined period (6th period moving means), and a condensing lens 7 for condensing the first laser beam B1 of parallel rays.

  Accordingly, the first laser beam B1 emitted from the first laser light source 2 is converted into a parallel light beam by the collimating lens 3, reflected by the fixed mirror 5, guided to the dichroic mirror 6, and from the second laser light source 11. The emitted second laser beam B2 is converted into parallel rays by the collimator lens 12 and guided to the dichroic mirror 6, and the first laser beam B1 and the second laser beam B2 are superimposed on the dichroic mirror 6. . The superposed first laser beam B1 and second laser beam B2 have their reflection angles changed at a predetermined cycle by rotating the rotary mirror 83 in the rotation direction 84 at a predetermined cycle. By rotating 83 in a rotation direction 85 different from the rotation direction 84 at a predetermined cycle, the reflection angle is changed at a predetermined cycle, and then the light is condensed by the condensing lens 7, and as a result, superimposed first The irradiation positions of the first laser beam B1 and the second laser beam B2 on the target member 10 are irradiated to the target member 10 while being weaved in a predetermined direction at a predetermined cycle, and desired laser processing is performed.

  That is, the laser processing apparatus 81 of the present embodiment is configured to have a weaving function that can rotate about a plurality of axes in a common optical system after the first laser beam B1 and the second laser beam B2 are superimposed. Accordingly, the weaving operation of the superposed first laser beam B1 and second laser beam B2 can be performed by controlling only the pair of rotating mirrors 82 and 83. Since the rotating mirrors 82 and 83 need to reflect the superimposed first laser beam B1 and second laser beam B2, mirrors that can reflect a wide range of wavelengths are used.

  In addition, it is desirable that either the rotary mirror 82 or the rotary mirror 83 weave the irradiation position of the superimposed first laser beam B1 on the target member 10 in the same direction as the traveling direction in which laser processing is performed. .

Further, the pair of rotating mirrors 82 and 83 shown in FIG. 14 needs to have a large area on the rear side of the pair of rotating mirrors depending on the weaving amount (see FIG. 15A). Therefore, in place of the rotating mirror 83 closer to the target member 10, as shown in FIG. 15B, a weaving operation is performed using a cylindrical mirror 91 having a semicylindrical convex cylindrical surface as a mirror surface. May be performed. When the cylindrical mirror 91 is used, even if the angle of the cylindrical mirror 91 is slightly changed, the reflection angles of the superimposed first laser beam B1 and second laser beam B2 can be greatly changed. The size of the Dolcal mirror 91 can be reduced. As a result, weaving operation with a high-speed cycle is facilitated, the motor for rotational driving can be downsized, and the entire laser processing apparatus can be downsized.
In FIG. 12 described above, the rotationally driven mirror has a large amplitude (rotation amount) when the drive amount is large. In particular, when it is used in a high frequency region, a high-performance drive motor is required and vibrations are generated. This is not desirable. Therefore, as shown in FIG. 13, by installing the cylindrical mirror 91 on the rear stage side of the weaving optical system, it becomes possible to drive it with a small amplitude. The configuration shown in FIG. 13 is the same as the configuration shown in FIG. 12 except for the cylindrical mirror 91.

Similarly, instead of the rotating mirror 83 closer to the target member 10, as shown in FIG. 16, a weaving operation may be performed using a toroidal mirror 92 having an annular convex toroidal surface as a mirror surface. Good. Even when the toroidal mirror 92 is used, even if the angle of the toroidal mirror 92 is slightly changed, the reflection angles of the superimposed first laser beam B1 and second laser beam B2 can be greatly changed. The dimensions can be reduced. As a result, weaving operation with a high-speed cycle is facilitated, the motor for rotational driving can be downsized, and the entire laser processing apparatus can be downsized.
In addition, by installing the toroidal mirror 92 on the rear side of the weaving optical system shown in FIG. 14, a wider area can be easily scanned.

  The laser processing apparatus and the laser processing method according to the present invention are suitable for application to lap welding, but can prevent the occurrence of welding defects when applied to not only lap welding but also normal welding. Furthermore, the present invention can be applied to other laser processing, for example, processing such as overlaying.

It is the schematic explaining an example (Example 1) of embodiment of the laser processing apparatus which concerns on this invention. It is a figure explaining the weaving operation | movement in the laser processing apparatus which concerns on this invention. 5 is a graph for explaining the number of generated porosity and penetration depth with respect to the weaving amount in the laser processing apparatus according to the present invention. In the laser processing apparatus which concerns on this invention, it is a figure explaining the formation condition of the keyhole by a weaving operation | movement. It is an X-ray photograph which shows the formation state of the keyhole and porosity in the presence or absence of a weaving operation | movement. It is an X-ray photograph which shows the condition of the welding defect in the presence or absence of the weaving operation | movement. It is the schematic explaining other examples (Example 2) of embodiment of the laser processing apparatus which concerns on this invention. It is the schematic explaining other examples (Example 3) of embodiment of the laser processing apparatus which concerns on this invention. It is the schematic explaining other examples (Example 4) of embodiment of the laser processing apparatus which concerns on this invention. It is the schematic explaining other examples (Example 5) of embodiment of the laser processing apparatus which concerns on this invention. It is the schematic explaining other examples (Example 6) of embodiment of the laser processing apparatus which concerns on this invention. It is the schematic explaining other examples (Example 7) of embodiment of the laser processing apparatus which concerns on this invention. It is the schematic explaining other examples (modified example of Example 7) of embodiment of the laser processing apparatus which concerns on this invention. It is the schematic explaining other examples (Example 8) of embodiment of the laser processing apparatus which concerns on this invention. It is the schematic explaining other examples (1st modification of Example 8) of embodiment of the laser processing apparatus which concerns on this invention. It is the schematic explaining other examples (2nd modification of Example 8) of embodiment of the laser processing apparatus which concerns on this invention. It is a figure explaining the cause which a welding defect generate | occur | produces in the lap welding by a laser.

Explanation of symbols

1, 21, 31, 41, 51, 61, 71, 81 Laser processing device 2, 32 First laser light source 3, 12 Collimating lens 4, 42, 74, 82, 83 Rotating mirror 5, 33 Fixed mirror 6 Dichroic mirror 7 Condensing lens 10 Target member 10a Lower plate 10b Upper plate 10c Gap 11, 62 Second laser light source 14, 15, 15a, 15b Keyhole 16 Molten pool 17 Bubble 22, 52 Parallel moving mirror 72 Rotating dichroic mirror 91 Cylindrical mirror 92 Toroidal mirror B1 First laser beam B2 Second laser beam

Claims (24)

A first laser light source that emits a first laser beam having one or a plurality of different wavelengths;
A second laser light source that emits a second laser beam having a shorter wavelength than the first laser beam or a plurality of wavelengths different from each other and having a condensing diameter larger than that of the first laser beam;
Superimposing means for superimposing the first laser beam and the second laser beam;
Condensing means for condensing the first laser beam and the second laser beam superimposed,
In a laser processing apparatus that performs desired laser processing by irradiating the target member with the focused first laser beam and the second laser beam,
The first laser beam under the condition that the irradiation position of the first laser beam on the target member is periodically moved in the same direction as the traveling direction in which laser processing is performed, and the periodic movement amount of the irradiation position is set so as to increase the penetration depth. A laser processing apparatus comprising a first periodic movement means having a size of 5% to 100%, preferably 40%, of an opening diameter of a keyhole formed by a beam. In the laser processing apparatus of Claim 1,
Furthermore, at least one or more second periodic movement means for periodically moving the irradiation position of the first laser beam on the target member in a direction different from the periodic movement direction is provided. In the laser processing apparatus of Claim 1 or Claim 2,
Furthermore, the laser processing apparatus characterized by providing the 3rd period moving means to periodically move the irradiation position in the said object member of the said 2nd laser beam to the same direction as the advancing direction which performs laser processing. In the laser processing apparatus of Claim 3,
Furthermore, at least one or more fourth period moving means for periodically moving the irradiation position of the second laser beam on the target member in a direction different from the period moving direction is provided. A first laser light source that emits a first laser beam having one or a plurality of different wavelengths;
A second laser light source that emits a second laser beam having a shorter wavelength than the first laser beam or a plurality of wavelengths different from each other and having a condensing diameter larger than that of the first laser beam;
Superimposing means for superimposing the first laser beam and the second laser beam;
Condensing means for condensing the first laser beam and the second laser beam superimposed,
In a laser processing apparatus that performs desired laser processing by irradiating the target member with the focused first laser beam and the second laser beam,
The irradiation position of the superimposed first laser beam and second laser beam on the target member is periodically moved in the same direction as the traveling direction in which laser processing is performed, and the amount of periodic movement of the irradiation position is determined by the penetration depth. The fifth period moving means is provided which has a size of 5% to 100%, preferably 40% of the opening diameter of the keyhole formed by the first laser beam under the condition of increasing Laser processing equipment. In the laser processing apparatus of Claim 5,
Furthermore, at least one or more sixth period moving means for periodically moving the irradiation positions of the superimposed first laser beam and second laser beam on the target member in a direction different from the period moving direction is provided. A laser processing apparatus characterized by the above. The laser processing apparatus according to claim 6,
A convex cylindrical body that periodically changes the reflection angle of the first laser beam and the second laser beam superimposed on the one close to the target member of the fifth period moving unit or the sixth period moving unit. A laser processing apparatus characterized by being a cylindrical mirror using a surface. The laser processing apparatus according to claim 6,
A convex toroid that periodically changes the reflection angle of the first laser beam and the second laser beam superimposed on the one close to the target member of the fifth period moving unit or the sixth period moving unit. A laser processing apparatus characterized by being a toroidal mirror using a surface. In the laser processing apparatus in any one of Claims 1 thru | or 8,
At least one of the first period moving means, the second period moving means, the third period moving means, the fourth period moving means, the fifth period moving means, or the sixth period moving means, A laser processing apparatus, characterized in that it is a rotating mirror that periodically changes the reflection angle of the first laser beam, the second laser beam, or the first laser beam and the second laser beam. In the laser processing apparatus in any one of Claims 1 thru | or 9,
At least one of the first period moving means, the second period moving means, the third period moving means, the fourth period moving means, the fifth period moving means, or the sixth period moving means, A laser processing apparatus, wherein the first laser beam, the second laser beam, or the optical path of the first laser beam and the second laser beam is a translation mirror that periodically translates. In the laser processing apparatus in any one of Claims 1 thru | or 10,
At least one of the first period moving means, the second period moving means, the third period moving means, and the fourth period moving means is the first laser light source, the second laser light source, or the first A laser processing apparatus, wherein the laser light source and the second laser light source are parallel moving means for periodically translating the incident positions of the second laser light source on an incident plane. In the laser processing apparatus in any one of Claims 1 thru | or 11,
The laser processing apparatus according to claim 1, wherein the target member is a superposed member. A first laser beam having one or a plurality of different wavelengths and a second laser beam having one or a plurality of wavelengths shorter than the first laser beam and having a condensing diameter larger than that of the first laser beam. Superimposed with the laser beam,
Condensing the superimposed first and second laser beams;
In a laser processing method for performing desired laser processing by irradiating a target member with the focused first laser beam and the second laser beam,
The first laser beam under the condition that the irradiation position of the first laser beam on the target member is periodically moved in the same direction as the traveling direction in which laser processing is performed, and the periodic movement amount of the irradiation position is set so as to increase the penetration depth. A laser processing method characterized in that the size is 5% to 100%, preferably 40%, of the opening diameter of the keyhole formed by the beam. The laser processing method according to claim 13,
Furthermore, the laser processing method characterized by periodically moving the irradiation position of the first laser beam on the target member in at least one direction different from the periodic movement direction. The laser processing method according to claim 13 or 14,
Furthermore, the laser processing method characterized by periodically moving the irradiation position of the second laser beam on the target member in the same direction as the traveling direction in which laser processing is performed. The laser processing method according to claim 15, wherein
Furthermore, the laser processing method, wherein the irradiation position of the second laser beam on the target member is periodically moved in at least one direction different from the periodic movement direction. A first laser beam having one or a plurality of different wavelengths and a second laser beam having one or a plurality of wavelengths shorter than the first laser beam and having a condensing diameter larger than that of the first laser beam. Superimposed with the laser beam,
Condensing the superimposed first and second laser beams;
In a laser processing method for performing desired laser processing by irradiating a target member with the focused first laser beam and the second laser beam,
The irradiation position of the superimposed first laser beam and second laser beam on the target member is periodically moved in the same direction as the traveling direction in which laser processing is performed, and the amount of periodic movement of the irradiation position is determined by the penetration depth. A laser processing method characterized in that the size is 5% to 100%, preferably 40%, of the opening diameter of the keyhole formed by the first laser beam under the condition of increasing The laser processing method according to claim 17,
Furthermore, the laser processing method characterized by periodically moving the irradiation positions of the superimposed first laser beam and second laser beam on the target member in one or more directions different from the periodic movement direction. The laser processing method according to claim 18,
The periodic movement is performed by periodically changing a reflection angle of the superimposed first laser beam and the second laser beam using a cylindrical mirror having a convex cylindrical surface as a mirror closer to the target member. Laser processing method characterized by performing. The laser processing method according to claim 18,
In the periodic movement, a toroidal mirror having a convex toroidal surface is used as a mirror closer to the target member, and the reflection angles of the superimposed first laser beam and second laser beam are periodically changed. Laser processing method characterized by performing. The laser processing method according to any one of claims 13 to 20,
The periodic movement is performed by periodically changing a reflection angle of the first laser beam, the second laser beam, or the first laser beam and the second laser beam using a rotating mirror. A laser processing method. The laser processing method according to any one of claims 13 to 21,
The periodic movement is performed by periodically translating the first laser beam, the second laser beam, or the optical path of the first laser beam and the second laser beam using a translation mirror. A featured laser processing method. The laser processing method according to any one of claims 13 to 22,
The periodic movement is performed by periodically translating the incident positions of the first laser light source, the second laser light source, or the first laser light source and the second laser light source on an incident plane. A laser processing method. The laser processing method according to any one of claims 13 to 23,
The laser processing method, wherein the target member is a superposed member.