WO2023176047A1

WO2023176047A1 - Laser welding device and laser welding method

Info

Publication number: WO2023176047A1
Application number: PCT/JP2022/043276
Authority: WO
Inventors: 大暉井本; 啓大野; 直彦小畑
Original assignee: パナソニックホールディングス株式会社
Priority date: 2022-03-18
Filing date: 2022-11-24
Publication date: 2023-09-21

Abstract

A laser welding device (100) welds together a first workpiece (110) and a second workpiece (111) and comprises: a laser emitting unit (101) that emits a laser light (105); a first detection unit (106) that differentiates and detects a plurality of types of light of different wavelength ranges and produced by the laser light (105) being irradiated onto the first workpiece (110); a second detection unit (107) that differentiates and detects a plurality of types of light of different wavelength ranges and produced by the laser light (105) being irradiated onto the second workpiece (111); and a determination unit (116) that determines, on the basis of the detection results from the first detection unit (106) and the second detection unit (107), the state of welding produced by the laser light (105) between the first workpiece (110) and the second workpiece (111).

Description

Laser welding equipment and laser welding method

The present disclosure relates to a laser welding device and a laser welding method.

Laser welding is known as a technique for joining multiple workpieces. As a technology related to laser welding, a technology for detecting a deviation in the irradiation position of laser light during laser welding (hereinafter sometimes simply referred to as "irradiation position deviation") has been developed.

Patent Document 1 discloses a laser welding device that detects an irradiation position based on the amount of light generated on a workpiece during laser welding. Patent Document 2 discloses a laser welding device that detects an irradiation position shift based on the intensity ratio of plasma light generated on a plurality of workpieces during laser welding.

Japanese Patent Application Publication No. 2014-176882 Japanese Patent Application Publication No. 6-269966

The laser welding device of the present disclosure includes:
A laser welding device for welding a first workpiece and a second workpiece,
a laser emitting section that emits laser light;
a first detection unit that distinguishes and detects multiple types of light in different wavelength ranges that are generated when the first workpiece is irradiated with the laser light;
a second detection unit that distinguishes and detects multiple types of light in different wavelength ranges that are generated when the second workpiece is irradiated with the laser light;
a determination unit that determines a welding state of the first workpiece and the second workpiece by the laser beam based on the detection results of the first detection unit and the second detection unit;
Equipped with

The laser welding method of the present disclosure includes:
A laser welding method for welding a first workpiece and a second workpiece, the method comprising:
Irradiates the laser beam,
distinguishing and detecting multiple types of light in different wavelength ranges generated by irradiating the first workpiece with the laser light;
distinguishing and detecting multiple types of light in different wavelength ranges generated by irradiating the second workpiece with the laser light;
Based on the detection result of the light generated at the first workpiece and the detection result of the light generated at the second workpiece, the laser beam is applied to the first workpiece and the second workpiece. The welding condition with the workpiece is determined.

FIG. 1 is a schematic diagram showing an example of a laser welding device according to an embodiment. FIG. 2A is a diagram for explaining the result of light detection by the detection unit. FIG. 2B is a diagram for explaining the result of light detection by the detection unit. FIG. 2C is a diagram for explaining the result of light detection by the detection unit. FIG. 3 is a diagram illustrating a scanning locus of a laser beam irradiation position during welding. FIG. 4A is an example of the detection result of the detection unit when the irradiation position of the laser beam is shifted. FIG. 4B is an example of the detection result of the detection unit when the laser beam irradiation position is shifted. FIG. 5A is an example of a detection result of the detection unit when a welding speed abnormality occurs. FIG. 5B is an example of a detection result of the detection unit when an abnormal welding speed occurs. FIG. 6 is a flowchart showing an example of the welding operation of the laser welding device according to the embodiment. FIG. 7 is a diagram showing the light detection results of the laser welding apparatus according to the embodiment and the light detection results of the inventions of Patent Document 1 and Patent Document 2. FIG. 8 is a diagram illustrating detectability of the laser welding apparatus according to the embodiment and the laser welding apparatuses of Patent Document 1 and Patent Document 2.

The laser welding devices of Patent Document 1 and Patent Document 2 only detect the irradiation position shift, and cannot detect the laser welding state in detail.

An object of the present disclosure is to provide a laser welding device and a laser welding method that can detect the laser welding state in more detail.

Hereinafter, each embodiment and modification example of the present disclosure will be described with reference to the drawings.

(Embodiment)
<Overall configuration>
FIG. 1 is a schematic diagram showing an example of a laser welding apparatus 100 according to an embodiment. This disclosure will be described using a Cartesian coordinate system (X, Y, Z). As shown by the arrows in FIG. 1, the Z-axis direction is the optical axis direction of the laser beam 105, the Y-axis direction is perpendicular to the Z-axis direction, and the X-axis direction is perpendicular to the Y-axis direction and the Z-axis direction. It is the direction. In FIG. 1, the workpieces 110 and 111 are arranged such that the boundary 109 between the workpieces 110 and 111 is along the Y-axis direction, and the width direction of the workpieces 110 and 111 is along the X-axis direction. .

The laser welding device 100 is a device that welds workpieces 110 and 111 that are butted against each other. In this embodiment, the workpieces 110 and 111 are made of different materials. For example, the workpiece 110 is made of Cu, and the workpiece 111 is made of Al. Note that the workpieces 110 and 111 are placed on a stage (not shown). By moving the laser head 104 that emits the laser beam 105 relative to the stage along the Y-axis direction, a boundary 109 between the workpieces 110 and 111 along the Y-axis direction is continuously welded.

The laser welding device 100 includes a laser emitting section 101, a first detection section 106, a second detection section 107, a control section 115, and a determination section 116.

The laser emitting unit 101 is a device that irradiates the workpieces 110 and 111 with laser light 105. The laser emitting section 101 includes, for example, a laser oscillator 102, a light transmission section 103, and a laser head 104.

A laser oscillator 102 oscillates a laser beam 105. For example, the laser light 105 is a laser light in a blue wavelength range, that is, a wavelength range of approximately 400 nm or more and 450 nm or less. Note that the laser light 105 does not necessarily have to be a laser light in a wavelength range of approximately 400 nm or more and 450 nm or less. Hereinafter, the wavelength range of the laser beam 105 will be described as approximately 400 nm or more and 450 nm or less.

Laser light 105 oscillated by laser oscillator 102 is transmitted to laser head 104 by optical transmission section 103.

The laser head 104 receives the laser beam 105 and emits it toward the workpieces 110 and 111. The laser head 104 includes a plurality of optical components, and the laser beam 105 is focused on a predetermined focal position by the plurality of optical components. When the predetermined focus position is located at the boundary 109 of the workpieces 110, 111, the workpieces 110, 111 are melted and joined together. The laser head 104 may be a laser head such as a single-core head or a galvano head provided with a galvano scanner, for example.

The first detection unit 106 and the second detection unit 107 are sensors that receive light and detect the light intensity for each wavelength range. Further, the first detection section 106 and the second detection section 107 output the detection results to the control section 115.

The first detection unit 106 and the second detection unit 107 are arranged around the laser head 104 so as to be able to individually receive light from the workpieces 110 and 111. For example, the first detection unit 106 is placed closer to the workpiece 110 than the second detection unit 107, so that it individually receives light from the workpiece 110. The second detection unit 107 is arranged closer to the workpiece 111 than the first detection unit 106, so that it individually receives light from the workpiece 111. Alternatively, the first detection unit 106 individually receives light from the workpiece 110 by having a filter for selectively receiving plasma light derived from Cu. The second detection unit 107 individually receives light from the workpiece 111 by having a filter for selectively receiving plasma light derived from Al.

A light receiving section (not shown) of the first detection section 106 is directed toward the focal position of the laser beam 105. Further, a light receiving section (not shown) of the second detection section 107 is directed toward the focal position of the laser beam 105.

By irradiating the boundary 109 between the workpieces 110 and 111 with the laser beam 105, multiple types of light are generated in each of the workpieces 110 and 111. In this embodiment, the plurality of types of light are plasma light 112a, 112b, reflected light 113a, 113b, and thermal radiation light 114a, 114b.

The plasma light 112a is light emitted from plasma generated when the workpiece 110 is melted by heating. The plasma light 112b is light emitted from plasma generated when the workpiece 111 is melted by heating. The molten states of the workpieces 110 and 111 are reflected in the plasma lights 112a and 112b. Plasma light 112a, 112b has different wavelengths depending on the material of workpieces 110, 111.

The reflected light 113a is the reflected light of the laser beam 105 reflected by the workpiece 110. The reflected light 113b is the reflected light of the laser beam 105 reflected by the workpiece 111. The surface conditions of the workpiece 110 and the workpiece 111 are reflected in the reflected lights 113a and 113b.

Thermal radiation light 114a is light emitted when the workpiece 110 reaches a high temperature state. The thermal radiation light 114b is light emitted when the workpiece 111 reaches a high temperature. The heat input state to the workpiece 110 and the workpiece 111 is reflected in the thermal radiation lights 114a and 114b.

The plasma light 112a, the reflected light 113a, and the thermal radiation light 114a have different wavelength ranges from each other. Similarly, the plasma light 112b, the reflected light 113b, and the thermal radiation light 114b have different wavelength ranges from each other. For example, when laser welding the workpiece 110 made of Cu and the workpiece 111 made of Al using laser light in a wavelength range of about 400 nm or more and 450 nm or less, the plasma beams 112a and 112b The wavelength of the reflected light beams 113a and 113b is between 400 nm and 500 nm, and the wavelength of the thermal radiation 114a and 114b is between 1200 nm and 1400 nm.

The first detection unit 106 and the second detection unit 107 have, for example, a spectroscopic system that spectrally separates the detection light, and detect the light intensity for each wavelength range via the spectroscopic system. The first detection unit 106 and the second detection unit 107 are equipped with optical components suitable for the wavelength range of the detection light as a spectroscopic system. Note that the first detection unit 106 and the second detection unit 107 have a spectral sensor that detects the light intensity for each wavelength, and even if the spectral sensor is used to detect the light intensity by distinguishing each wavelength range. good.

Therefore, the first detection unit 106 can distinguish and detect the plasma light 112a, the reflected light 113a, and the thermal radiation light 114a. Further, the second detection unit 107 can distinguish and detect the plasma light 112b, the reflected light 113b, and the thermal radiation light 114b.

The control unit 115 controls the laser welding operation. The control unit 115 is, for example, a computer having a CPU (Central Processing Unit). The control section 115 controls the laser beam 105 to be emitted from the laser emitting section 101 . Specifically, the control unit 115 controls the oscillation and stopping of the laser beam 105, the oscillation output of the laser oscillator 102, and the like.

Furthermore, the control unit 115 relatively moves the irradiation position of the laser beam 105 with respect to the workpieces 110 and 111. The control unit 115 moves the laser head 104 relative to the workpieces 110 and 111, for example.

The control unit 115 may perform wobbling control, for example. Wobbling control is a control in which the irradiation position is moved so that the irradiation position draws a circular locus, and is a control that is mainly executed during dissimilar welding.

Note that the control unit 115 may be configured to move the stage on which the workpieces 110 and 111 are placed relative to the irradiation position of the laser beam 105, or may be configured to move the stage and the irradiation position of the laser beam 105. It may be configured to move both positions.

The determination unit 116 acquires the detection results of the first detection unit 106 and the second detection unit 107, and determines the laser welding state at the boundary 109 between the workpieces 110 and 111 based on the acquired detection results. Specifically, the determining unit 116 can determine multiple types of welding abnormalities based on the molten state, surface state, and heat input state at the boundary 109, such as misalignment of the irradiation position of the laser beam 105, and Abnormal welding speed at the irradiation position can be detected.

The irradiation position shift means that the irradiation position moves away from the boundary 109 in the X-axis direction. If the irradiation position has shifted, either the workpieces 110 or 111 will not be sufficiently irradiated with the laser beam 105.

Welding speed abnormality means that the relative scanning speed of the irradiation position of the laser beam 105 (hereinafter referred to as "relative scanning speed") with respect to the workpieces 110 and 111 is too fast. When an abnormal welding speed occurs, at least one of the workpieces 110 and 111 is not sufficiently melted.

Furthermore, the determination unit 116 calculates the amount of correction for the laser welding operation by the laser welding apparatus 100 based on the laser welding state. The amount of correction includes, for example, the amount of shift of the irradiation position and the amount of variation in the relative scanning speed of the irradiation position.

<Light intensity detection>
FIGS. 2A to 2C are diagrams for explaining light detection results by the first detection unit 106 and the second detection unit 107. In FIGS. 2A to 2C, the vertical axis represents detected light intensity and the horizontal axis represents time. In FIGS. 2A to 2C, the vertical axis indicates "detection light intensity," but in reality, it is the intensity of any one of plasma light, reflected light, and thermal radiation light.

In FIG. 2A, the light intensity of the detection units 106 and 107 is always within the reference range. The reference range is a light intensity range in which the light intensity can be when the workpiece 110 and the workpiece 111 are laser welded without any abnormality. The reference range is set for each type of light. When the detected light intensity is always within the reference range, the determination unit 116 determines that the detected light intensity is "normal".

In FIG. 2B, the light intensity of the detection units 106 and 107 is always greater than the reference range. In this case, the determining unit 116 determines that the detected light intensity is "upper limit abnormality".

In FIG. 2C, the light intensity of the detection units 106 and 107 is always smaller than the reference range. In this case, the determining unit 116 determines that the detected light intensity is "lower limit abnormality".

<Example of determining welding abnormality>
Hereinafter, determination of a welding abnormality will be described using (1) irradiation position deviation, (2) welding speed abnormality, and (3) irradiation position deviation and welding speed abnormality as examples.

(1) Irradiation Position Shift The determination of irradiation position shift by the determination unit 116 will be described with reference to FIGS. 3, 4A, and 4B.

FIG. 3 is a diagram illustrating the scanning locus of the irradiation position of the laser beam 105 during welding. 203 in FIG. 3 is a scanning locus of the irradiation position of the laser beam 105 during normal welding. 204 in FIG. 3 is a scanning locus of the irradiation position when the irradiation position shifts.

SP1 to SP5 in FIG. 3 are the irradiation ranges of the laser beam 105. When the laser beam 105 is irradiating the irradiation ranges SP1 to SP4, the laser beam 105 is irradiating both the workpieces 110 and 111. When the laser beam 105 is irradiating the irradiation range SP5, the workpiece 110 is irradiated with the laser beam 105, but the workpiece 111 is not irradiated with the laser beam 105.

When the irradiation position is scanned like the trajectory 203, the light intensity of the plasma light 112a, 112b, reflected light 113a, 113b, and thermal radiation light 114a, 114b is within the reference range within the welding time.

FIGS. 4A and 4B are examples of detection results of the detection units 106 and 107 when the irradiation position shifts toward the workpiece 110 side. FIGS. 4A and 4B show detection results when the laser beam 105 is irradiated to the irradiation range SP5 (see FIG. 3). 4A shows the detection result by the first detection unit 106, and FIG. 4B shows the detection result by the second detection unit 107.

When the irradiation position is scanned like the trajectory 204, the intensity of one of the multiple types of light falls outside the reference range.

When the laser beam 105 is irradiated to the irradiation range SP5, the workpiece 111 is less likely to be melted than when the laser beam 105 is irradiated to the irradiation range SP4, and the amount of plasma on the workpiece 111 is reduced. do. As a result, the amount of plasma light 112b indicating emission from the plasma of the workpiece 111 decreases.

Therefore, as shown in FIG. 4B, when the laser beam 105 is irradiating the irradiation range SP5, a value smaller than the reference range is detected as the intensity of the plasma light 112b.

Furthermore, when the laser beam 105 is irradiated to the irradiation range SP5, the amount of irradiation of the laser beam 105 to the workpiece 111 is smaller than when the laser beam 105 is irradiated to the irradiation range SP4, so the workpiece The amount of reflected light 113b indicating reflection from the object 111 decreases.

Therefore, as shown in FIG. 4B, when the laser beam 105 is irradiated to the irradiation range SP5, a value smaller than the reference range is detected as the intensity of the reflected light 113b.

When the laser beam 105 is irradiated to the irradiation range SP4, the workpiece 110 and the workpiece 111 are heated evenly. However, when the laser beam 105 is irradiated to the irradiation range SP5, the workpiece 110 is heated even more, and the workpiece 111 is less likely to be heated. As a result, compared to when the laser beam 105 is irradiated to the irradiation range SP4, the amount of heat input to the workpiece 110 is large, and the amount of thermal radiation light 114a indicating emission from the workpiece 110 is large. On the other hand, the amount of heat input to the workpiece 111 is small, and the amount of thermal radiation light 114b indicating emission from the workpiece 111 is small.

Therefore, when the laser beam 105 is irradiated to the irradiation range SP5, as shown in FIG. 4A, a value larger than the reference range is detected as the intensity of the thermal radiation light 114a. Further, as shown in FIG. 4B, a value smaller than the reference range is detected as the intensity of the thermal radiation light 114b.

Therefore, the determination unit 116 determines that the intensities of the plasma light 112a and the reflected light 113a are "normal", the intensity of the thermal radiation light 114a is "upper limit abnormal", and that the intensities of the plasma light 112b, the reflected light 113b, and the thermal radiation light 114b are If the intensity is "lower limit abnormality", it is determined that the irradiation position has shifted toward the workpiece 110 side.

Note that the determination unit 116 determines that the intensities of the plasma light 112b and the reflected light 113b are "normal", that the thermal radiation 114b is "abnormal at the upper limit", and that the intensities of the plasma light 112a, the reflected light 113a, and the thermal radiation 114a are "lower limit". If it is "abnormal", it is determined that a shift in the irradiation position toward the workpiece 111 has occurred.

(2) Welding speed abnormality The determination of welding speed abnormality by the determination unit 116 will be described with reference to FIGS. 5A and 5B.

FIG. 5A is an example of a detection result of the first detection unit 106 when an abnormality in welding speed occurs. FIG. 5B is an example of a detection result of the second detection unit 107 when an abnormal welding speed occurs.

The detection results shown in FIGS. 5A and 5B are the results when the workpiece 110 is sufficiently melted and the workpiece 111 is not sufficiently melted. In other words, the detection results in FIGS. 5A and 5B indicate that the irradiation position moves relative to the workpieces 110 and 111 at a scanning speed that is such that the workpiece 110 is sufficiently melted and the workpiece 111 is not sufficiently melted. This is the result when

Although Cu (melting point: 1085° C.) has a higher melting point than Al (melting point: 660° C.), it easily absorbs laser light 105 (wavelength range of approximately 400 nm or more and 450 nm or less). Therefore, Cu (melting point: 1085° C.) is easier to heat and melt than Al (melting point: 660° C.). Therefore, when laser welding is performed using the laser beam 105, the workpiece 110 is more easily melted than the workpiece 111. If the wavelength range of the laser beam 105 used changes, the workpiece 111 may be more easily melted than the workpiece 110.

In the following description, the fact that the workpiece is not sufficiently melted may be referred to as "melting abnormality".

If there is no melting abnormality in the workpiece 110, the intensity of the plasma light 112a, reflected light 113a, and thermal radiation light 114a all fall within the reference range during the welding time.

When there is a melting abnormality in the workpiece 111, the amount of plasma on the workpiece 111 is small, so the amount of plasma light 112b indicating emission from the plasma of the workpiece 111 is small.

In addition, if there is a melting abnormality in the workpiece 111, the workpiece 111 is not sufficiently melted and the volume of the solid workpiece 111 is large, so reflection from the surface of the workpiece 111 is shown. The amount of reflected light 113b is large.

Further, the presence of melting abnormality in the workpiece 111 means that the temperature of the workpiece 111 is low and the amount of heat input is small. That is, when there is a melting abnormality in the workpiece 111, the amount of thermal radiation light 114b indicating emission from the workpiece 111 is small.

Therefore, the determination unit 116 determines that the intensities of the plasma light 112a, the reflected light 113a, and the thermal radiation light 114a are "normal," that the plasma light 112b and the thermal radiation light 114b are "lower limit abnormal," and that the reflected light 113b is "abnormal." If it is "upper limit abnormality", it is determined that a welding speed abnormality has occurred. The determination unit 116 may further determine that the workpiece 111 has a melting abnormality.

Note that the determination unit 116 also determines that welding speed abnormality has occurred when the plasma light 112a, 112b and the thermal radiation light 114a, 114b are "lower limit abnormality" and the reflected light beams 113a, 113b are "upper limit abnormality". It is determined that there is. The determining unit 116 may further determine that melting abnormality has occurred in both the workpieces 110 and 111.

(3) Irradiation position deviation and welding speed abnormality In laser welding, when an irradiation position deviation toward the workpiece 110 side occurs and abnormal melting of the workpiece 111 occurs due to the welding speed abnormality, Results similar to the detection results in FIGS. 4A and 4B are obtained.

That is, the intensities of the plasma light 112a and the reflected light 113a are "normal", the thermal radiation light 114a is the "upper limit abnormality", and the plasma light 112b, the reflected light 113b, and the thermal radiation light 114b are the "lower limit abnormality".

In this way, if the detection pattern when an irradiation position shift and welding speed abnormality occurs is the same as the detection pattern when an irradiation position shift occurs, the laser welding apparatus 100 first determines the irradiation position shift. , and eliminate the irradiation position shift according to the determination result. Thereafter, the laser welding apparatus 100 determines whether the welding speed is abnormal, and eliminates the welding position shift according to the determination result.

In addition, in laser welding, if the irradiation position shifts toward the workpiece 111 side and abnormal melting of the workpieces 110 and 111 occurs due to an abnormal welding speed, the plasma light 112a and the reflected light 113a , and the thermal radiation light 114a is the "lower limit abnormality", the plasma light 112b and the thermal radiation light 114b are the "lower limit abnormality", and the intensity of the reflected light 113b is the "upper limit abnormality".

As described above, when the detection pattern when the irradiation position shift and welding speed abnormality occur is different from the detection pattern when the irradiation position shift occurs, the laser welding apparatus 100 first The positional deviation may be resolved and then the welding speed abnormality may be resolved. Alternatively, the laser welding apparatus 100 may be controlled so as to simultaneously eliminate the irradiation position shift and the welding speed abnormality.

<Laser welding operation>
Next, a laser welding operation by the laser welding apparatus 100 will be explained. FIG. 6 is a flowchart showing an example of the laser welding operation of the laser welding apparatus 100. In the following description, it will be assumed that the targets for determining welding abnormality are irradiation position deviation and welding speed abnormality.

First, in step S11, the control unit 115 starts emitting and scanning the laser beam 105. Specifically, the control unit 115 controls the laser emitting unit 101 to start emitting the laser beam 105 toward the boundary 109 between the workpieces 110 and 111, and also causes the laser head 104 to move along the boundary 109. Move at a predetermined speed. The predetermined speed is a predetermined scanning speed.

Next, in step S12, the first detection unit 106 and the second detection unit 107 start detecting light from the workpiece 110 and light from the workpiece 111, respectively.

Next, in step S13, the determination unit 116 determines whether the light intensity of the plasma light 112a, 112b, reflected light 113a, 113b, and thermal radiation light 114a, 114b is "normal", "upper limit abnormality", or "lower limit abnormality". Based on the determination result, it is determined whether there is a welding abnormality.

For example, when the intensities of the plasma lights 112a and 112b, the reflected lights 113a and 113b, and the thermal radiation lights 114a and 114b are all "normal", the determination unit 116 determines that there is "no welding abnormality", and determines that there is no welding abnormality. If the strength of is "upper limit abnormality" or "lower limit abnormality", it is determined that "welding abnormality exists".

If it is determined that "there is a welding abnormality" ("YES" in step S13), the process moves to step S14, and the determination unit 116 performs a welding process based on the light intensity detection pattern and a preset abnormality detection pattern. , to identify the type of welding abnormality. An abnormality detection pattern is set for each type of welding abnormality. The abnormality detection patterns include, for example, the following abnormality detection patterns (E1) to (E4).

(E1) Pattern when the irradiation position shifts toward the workpiece 110 side The intensities of the plasma light 112a and the reflected light 113a are "normal", the thermal radiation light 114a is "upper limit abnormal", and the plasma light 112b, the reflected light 113b, And the thermal radiation light 114b is "lower limit abnormality".

(E2) Pattern when the irradiation position shifts toward the workpiece 111 side The intensities of the plasma light 112b and the reflected light 113b are "normal", the thermal radiation light 114b is "abnormal upper limit", and the plasma light 112a, the reflected light 113a, And the thermal radiation light 114a is "lower limit abnormality".

(E3) Pattern when welding speed is abnormal (melting abnormality of workpiece 111) The intensity of plasma light 112a, reflected light 113a, and thermal radiation light 114a is "normal", and the intensity of plasma light 112b and thermal radiation light 114b is "normal". "Lower limit abnormality" and the reflected light 113b are "upper limit abnormality".

(E4) Pattern when welding speed abnormality (melting abnormality of workpieces 110, 111) Plasma light 112a, 112b and thermal radiation light 114a, 114b are "lower limit abnormality", and reflected light 113a, 113b are "upper limit abnormality" Abnormal”.

If the "welding abnormality" is accompanied by at least "irradiation position shift" (patterns (E1) and (E2), etc.) ("YES" in step S15), the process moves to step S16, and the determination unit 116 The amount of deviation in the intensity of the plurality of types of light with respect to the reference range is calculated for each type of light. Next, in step S17, the determination unit 116 calculates the amount of shift with respect to the irradiation position at the time of determination in step S13, based on the amount of shift for each type of light. This shift amount is a value that is estimated to cause all of the intensities of the plurality of types of light to fall within the reference range when the irradiation position is brought closer to the boundary 109 by the shift amount.

Next, in step S18, the control unit 115 corrects the irradiation position based on the shift amount. Specifically, the control unit 115 shifts the laser head 104 by a shift amount in the X-axis direction to bring the irradiation position closer to the boundary 109. After that, the process moves to step S13.

If the "welding abnormality" is not accompanied by "irradiation position shift" but is accompanied by "welding speed abnormality" (patterns (E3) and (E4), etc.) ("NO" in step S15), the process moves to step S19. Then, the determination unit 116 calculates the amount of deviation in the intensity of the plurality of types of light with respect to the reference range for each type of light. Next, in step S20, the determination unit 116 calculates the amount of variation with respect to the scanning speed at the time of determination in step S13, based on the amount of shift for each type of light. This amount of variation is a value that is estimated to cause all of the intensities of the plurality of types of light to fall within the reference range when the scanning speed is reduced by the amount of variation.

Next, in step S21, the control unit 115 corrects the scanning speed based on the amount of variation. Specifically, the control unit 115 reduces the scanning speed by the amount of variation. After that, the process moves to step S13.

If it is determined that there is "no welding abnormality" ("NO" in step S13), the process proceeds to step S22, and the control unit 115 determines whether laser welding is completed. For example, the control unit 115 may determine whether laser welding is completed based on whether the irradiation position has reached the target position.

If the laser welding is not completed (“NO” in step S22), the process moves to step S13, and the necessary processes in steps S13 to S21 are repeated until the laser welding is completed.

When the laser welding is completed (“YES” in step S22), the process moves to step S23, where the control unit 115 finishes emitting the laser beam and scanning the irradiation position, and the detection units 106 and 107 Terminate detection. In step S23, specifically, the control unit 115 stops the movement of the laser head 104 and the irradiation of the laser beam 105 by the laser emitting unit 101.

Note that in laser welding, if both an irradiation position deviation and a welding speed abnormality occur, it is determined in step S15 that the welding abnormality is an "irradiation position deviation", and after the irradiation position is shifted to an appropriate position, step S15 is performed. In S15, it is determined that the welding abnormality is "abnormal welding speed." Therefore, the control unit 115 first eliminates the irradiation position shift as a first step, and eliminates the welding speed abnormality as a second step.

Furthermore, the following abnormality detection pattern (E5) may be included in the preset abnormality detection patterns.

(E5) Pattern when irradiation position shift toward workpiece 111 side and welding speed abnormality (melting abnormality of workpieces 110 and 111) Plasma light 112a, reflected light 113a, thermal radiation light 114a, plasma light 112b, The intensity of the thermal radiation 114b is "lower limit abnormality" and the intensity of the reflected light 113b is "upper limit abnormality".

When the detection pattern corresponds to the abnormality detection pattern (E5), the determination unit 116 determines that the welding abnormality is “irradiation position deviation” and “welding speed abnormality”, and the control unit 115 changes the irradiation position. The scanning speed may be changed to the appropriate speed at the same time as shifting to the appropriate position. That is, the control unit 115 may eliminate the irradiation position shift and the welding speed abnormality at the same time.

In addition, in step S13, the determination unit 116 determines that "welding abnormality exists" when the detection pattern of each light intensity corresponds to any of the preset abnormality detection patterns, and selects any abnormality detection pattern. If this does not apply, it may be determined that there is no welding abnormality.

<Comparison between embodiment and conventional invention>
Advantages of the laser welding device 100 according to the embodiment over the laser welding devices of Patent Document 1 and Patent Document 2 will be described with reference to FIGS. 7 and 8.

FIG. 7 is a diagram showing the light detection results of the laser welding apparatus 100 according to the embodiment and the light detection results of the inventions of Patent Document 1 and Patent Document 2. FIG. 7 shows three patterns of welding conditions: "normal", "deviation of irradiation position toward workpiece 110 side", and "abnormal welding speed accompanied by melting abnormality of workpiece 111". . FIG. 7 shows the optical detection results by the detection unit on the workpiece 110 side and the detection unit on the workpiece 111 side for each welding state.

FIG. 8 is a diagram illustrating detectability of the laser welding device 100 according to the embodiment and the laser welding devices of Patent Document 1 and Patent Document 2. "A" in FIG. 8 indicates that it is detectable, "C" indicates that it is not detectable, and "B" indicates that some welding abnormality can be detected, but the type of welding abnormality is This shows that it is not possible to distinguish between

In Patent Document 1, a detection unit on the workpiece 110 side and a detection unit on the workpiece 111 side detect light generated in the workpieces 110 and 111 without distinguishing them for each wavelength range. Therefore, the detection target in Patent Document 1 is the intensity of light including plasma light 112a, reflected light 113a, and thermal radiation light 114a, and the intensity of light including plasma light 112b, reflected light 113b, and thermal radiation light 114b. It is strength.

When a "deviation in the irradiation position toward the workpiece 110 side" occurs, the intensity of the light detected by the detection unit on the workpiece 110 side in Patent Document 1 becomes "upper limit abnormality", and the intensity on the workpiece 111 side The intensity of light detected by the detection unit is at the "lower limit abnormality".

On the other hand, when "abnormal welding speed accompanied by abnormal melting of the workpiece 111" occurs, the intensity of light detected by the detection unit on the workpiece 110 side of Patent Document 1 becomes "normal". Furthermore, although the light intensity of the plasma light 112b indicating emission from the plasma of the workpiece 111 and the thermal radiation light 114b indicating emission from the workpiece 111 decreases, the reflected light 113b indicating reflection from the workpiece 111 decreases. The amount of light increases. That is, the total amount of light generated at the workpiece 111 is approximately the same as the total amount of light generated at the workpiece 111 when "welding abnormality" does not occur. Therefore, the intensity of the light detected by the detection section on the workpiece 111 side is also "normal".

Therefore, as shown in FIG. 8, although the laser welding device of Patent Document 1 can detect "irradiation position shift", it cannot detect "abnormal welding speed".

In Patent Document 2, a detection unit on the workpiece 110 side and a detection unit on the workpiece 111 side detect only plasma light generated in the workpieces 110 and 111. Therefore, the detection targets in Patent Document 2 are the intensity of the plasma light 112a and the intensity of the plasma light 112b.

When a "deviation in the irradiation position toward the workpiece 110 side" occurs, the intensity of the plasma light 112a detected by the detection unit on the workpiece 110 side of Patent Document 2 becomes "normal", and the intensity on the workpiece 111 side is The intensity of the light detected by the detection unit is at the "lower limit abnormality".

Further, when "abnormal welding speed accompanied by abnormal melting of the workpiece 111" occurs, the intensity of the plasma light 112a detected by the detection unit on the workpiece 110 side of Patent Document 2 becomes "normal", The intensity of the light detected by the detection unit on the workpiece 111 side becomes the "lower limit abnormality".

In other words, based on the detection results, welding abnormalities are determined when "irradiation position shift on the workpiece 110 side" occurs and when "abnormal welding speed accompanied by abnormal melting of the workpiece 111" occurs. cannot distinguish between types.

Therefore, as shown in FIG. 8, in the laser welding apparatus of Patent Document 2, "deviation of the irradiation position toward the workpiece 110" and "abnormal welding speed accompanied by abnormal melting of the workpiece 111" occur. It is possible to detect that some kind of welding abnormality has occurred. However, the laser welding apparatus of Patent Document 2 cannot distinguish between "irradiation position shift" and "abnormal welding speed".

In the embodiment, in each case of "normal", "irradiation position shift", and "abnormal welding speed", the intensity of the plasma light 112a, the intensity of the reflected light 113a, the intensity of the thermal radiation light 114a, the intensity of the plasma light 112b, and the reflected The detection patterns of the intensity of the light 113b and the intensity of the thermal radiation light 114b are different.

Therefore, as shown in FIG. 8, the laser welding apparatus 100 according to the embodiment can detect "irradiation position shift" and "welding speed abnormality" as welding abnormalities. Furthermore, it is possible to distinguish at least whether "irradiation position shift" or "abnormal welding speed" is occurring.

In addition, in the above description, the laser welding apparatus 100 was explained as having one each of the first detection section 106 and the second detection section 107, but the first detection section 106 and the second detection section 107 are Two or more of each may be provided. Thereby, the welding state can be determined in detail during biaxial laser welding. For example, when joining three or more workpieces, the boundary between the workpieces may include a line along the X-axis direction and a line along the Y-axis direction. In this case, laser welding can be performed while determining the welding state in detail without changing the orientation of the workpiece. Further, even when the boundary between workpieces extends diagonally with respect to the scanning direction of the irradiation position, laser welding can be performed while determining the welding state in detail.

As described above, the laser welding apparatus 100 according to the embodiment welds the boundary 109 by abutting the workpiece 110 and the workpiece 111, and includes a laser emitting section 101 that emits a laser beam 105, A first detection unit 106 that distinguishes and detects multiple types of light in different wavelength ranges that are generated when the workpiece 110 is irradiated with the laser light 105; A second detection unit 107 that distinguishes and detects a plurality of types of light in different wavelength ranges that occur, and a workpiece 110 that is irradiated with laser light 105 based on the detection results of the first detection unit 106 and the second detection unit 107. and a determination unit 116 that determines the welding state of the workpiece 111 and the workpiece 111.

In this way, by distinguishing and detecting multiple types of light in different wavelength ranges, multiple types of welding abnormalities can be distinguished and determined. Therefore, the laser welding state can be detected in detail. Thereby, the laser welding state can be accurately grasped, so that appropriate laser welding control can be executed depending on the welding state. As a result, precise laser welding can be achieved.

The determination unit 116 determines multiple types of welding abnormalities based on the detection results of the detection units 106 and 107. For example, the plurality of types of welding abnormalities include a deviation in the irradiation position of the laser beam 105 and an abnormality in the welding speed at the irradiation position.

In this way, multiple types of welding abnormalities can be detected, so appropriate laser welding control can be performed depending on the welding state.

The plurality of types of light include plasma light 112a, 112b, reflected light 113a, 113b, and thermal radiation light 114a, 114b from the workpiece 110 and workpiece 111.

By detecting three types of light: plasma light, reflected light, and thermal radiation light, various welding abnormalities can be distinguished and detected. For example, if the focusing position of the laser beam 105 in the optical axis direction of the laser beam 105 (hereinafter referred to as the "focus position") is shifted, even if the intensity of the thermal radiation lights 114a and 114b is "normal". Regardless, the intensity of the plasma lights 112a and 112b reaches the "lower limit abnormality". Therefore, by detecting the plasma lights 112a and 112b in addition to the reflected lights 113a and 113b and the thermal radiation lights 114a and 114b, it is possible to determine a welding abnormality caused by a focus position shift.

Additionally, the accuracy of detecting welding abnormalities can be improved. For example, as shown in FIG. 7, when detecting a welding speed abnormality, reflected light 113a, 113b and thermal radiation light 114a, 114b may be detected. However, by detecting the plasma lights 112a and 112b, it is possible to directly determine whether either of the workpieces 110 or 111 is not sufficiently melted. Therefore, by detecting the plasma lights 112a and 112b in addition to the reflected lights 113a and 113b and the thermal radiation lights 114a and 114b, welding abnormalities in the workpieces 110 and 111 can be determined more accurately.

The workpiece 110 and the workpiece 111 are made of different materials. In this embodiment, since the plasma lights 112a and 112b are detected, the welding states of the workpieces 110 and 111 can be detected in more detail.

The control unit 115 of this embodiment controls the relative movement of the irradiation position of the laser beam 105 with respect to the workpiece 110 and the workpiece 111.

Specifically, the control unit 115 moves the irradiation position relatively closer to the boundary 109 based on the determination result by the determination unit 116. Further, the control unit 115 changes the relative moving speed of the irradiation position with respect to the workpiece 110 and the workpiece 111 based on the determination result by the determination unit 116. Thereby, laser welding can be appropriately performed based on the determination result of welding abnormality.

(Modified example)
In the embodiment, the laser welding apparatus 100 has been described as determining irradiation position deviation and welding speed abnormality, but it may also determine welding abnormalities other than irradiation position deviation and welding speed abnormality. For example, if all of the detection results for multiple types of light are "lower limit abnormality," the laser welding device 100 determines that the laser light 105 is "insufficient in intensity" and adjusts the laser emitting part to increase the laser oscillation intensity. 101 may be controlled. Further, the laser welding apparatus 100 controls the laser beam when all of the detection results of the plurality of types of light remain at the "lower limit abnormality" even though the laser emitting unit 101 is controlled so that the laser oscillation intensity is increased. It may be determined that there is a "component abnormality" in the emission unit 101.

Furthermore, in the embodiment, it has been explained that the first detection unit 106 and the second detection unit 107 separately detect plasma light, reflected light, and thermal radiation light. However, if any two types of light among plasma light, reflected light, and thermal radiation light can be detected separately, multiple types of welding abnormalities can be discriminated and determined. In fact, FIG. 7 shows that it is possible to distinguish between irradiation position deviation and welding speed abnormality by obtaining detection results for two types of light among plasma light, reflected light, and thermal radiation light.

For example, the intensities of the plasma lights 112a, 112b and the reflected lights 113a, 113b when there is a shift in the irradiation position toward the workpiece 110 are "normal", "lower limit abnormal", "normal", and "lower limit". "Abnormal." The intensities of the plasma lights 112a, 112b and the reflected lights 113a, 113b when welding speed abnormality accompanied by melting abnormality of the workpiece 111 are "normal", "lower limit abnormality", "normal", and "upper limit abnormality". "Abnormal." That is, since the two detection patterns are different, it is possible to distinguish between the irradiation position shift and the welding speed abnormality based on the detection results of the two types of light.

Although the embodiment describes butt welding between the workpiece 110 and the workpiece 111, the present disclosure can also be applied to welding other than butt welding. For example, the present disclosure can be applied to the case where one of the workpieces 110 and 111 is overlapped with the other and welded. In that case, the irradiation position is scanned along the boundary between the workpieces 110 and 111 when the workpieces 110 and 111 are viewed along the optical axis direction of the laser beam 105.

Further, in the embodiment, the welding of the workpieces 110 and 111 made of different materials has been described, but the present invention can be applied to welding of a plurality of workpieces made of the same material.

This can be realized by making various modifications to the above embodiments and modifications that those skilled in the art can think of, or by arbitrarily combining the components and functions of the above embodiments without departing from the spirit of the present disclosure. The present disclosure also includes forms in which:

According to the present disclosure, it is possible to provide a laser welding device and a laser welding method that can detect the laser welding state in more detail.

The present disclosure can be suitably applied to a laser welding device that laser welds a plurality of workpieces.

100 Laser welding device 101 Laser emission part 102 Laser oscillator 103 Light transmission part 104 Laser head 105 Laser light 106 First detection part 107 Second detection part 109 Boundary 110 Workpiece 111 Workpiece 112a, 112b Plasma light 113a, 113b Reflected light 114a, 114b Thermal radiation light 115 Control section 116 Judgment section

Claims

A laser welding device for welding a first workpiece and a second workpiece,
a laser emitting section that emits laser light;
a first detection unit that distinguishes and detects multiple types of light in different wavelength ranges that are generated when the first workpiece is irradiated with the laser light;
a second detection unit that distinguishes and detects multiple types of light in different wavelength ranges that are generated when the second workpiece is irradiated with the laser light;
a determination unit that determines a welding state of the first workpiece and the second workpiece by the laser beam based on the detection results of the first detection unit and the second detection unit;
Laser welding equipment equipped with.
The determination unit determines multiple types of welding abnormalities based on the detection results,
The plurality of types of welding abnormalities include a deviation in the irradiation position of the laser beam, and an abnormality in the welding speed at the irradiation position.
The laser welding device according to claim 1.
The plurality of types of light include plasma light, reflected light, and thermal radiation light from the first workpiece and the second workpiece,
The laser welding device according to claim 1 or 2.
The first workpiece and the second workpiece are formed of mutually different materials;
A laser welding device according to any one of claims 1 to 3.
each comprising a plurality of the first detection units and the second detection units;
A laser welding device according to any one of claims 1 to 4.
further comprising a control unit that controls relative movement of the irradiation position of the laser beam with respect to the first workpiece and the second workpiece;
A laser welding device according to any one of claims 1 to 5.
The control unit moves the irradiation position relatively close to a boundary between the first workpiece and the second workpiece based on a determination result by the determination unit.
The laser welding device according to claim 6.
The control unit changes a relative moving speed of the irradiation position with respect to the first workpiece and the second workpiece based on the determination result by the determination unit.
The laser welding device according to claim 6 or 7.
A laser welding method for welding a first workpiece and a second workpiece, the method comprising:
Irradiates the laser beam,
distinguishing and detecting multiple types of light in different wavelength ranges generated by irradiating the first workpiece with the laser light;
distinguishing and detecting multiple types of light in different wavelength ranges generated by irradiating the second workpiece with the laser light;
Based on the detection result of the light generated at the first workpiece and the detection result of the light generated at the second workpiece, the laser beam is applied to the first workpiece and the second workpiece. Determine the welding condition with the workpiece,
Laser welding method.