Laser processing method

Abstract

To enhance the machining quality and machining speed of work-piece.SOLUTION: A work-piece W has a first machining object portion w1 and a second machining object portion w2. The second machining object portion w2 is at a position separated from the first machining object portion w1. In a first process, a first laser beam L1 is emitted to the first machining object portion w1. In a second process, a second laser beam L2 is emitted to the first machining object portion w1 to which the first laser beam L1 is emitted. In a third process, the first laser beam L1 is emitted to the second machining object portion w2. In a fourth process, the second laser beam L2 is emitted to the second machining object portion w2 to which the first laser beam L1 is emitted.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a laser processing method.

Background Art

[0002] Patent Document 1 discloses a laser processing optical apparatus including an optical system that guides two lasers with different wavelengths onto a coaxial optical path and overlaps them, and a condenser lens that condenses the output beams of the two lasers overlapped on the coaxial optical path onto a workpiece (work to be processed).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, the laser light with a short wavelength has a high laser absorption rate for workpieces made of high-reflectivity materials such as copper and aluminum, where the reflectivity of the laser light is relatively high compared to that of iron, etc., but the maximum output of the laser light is low, resulting in a slow processing speed.

[0005] On the other hand, the laser light with a long wavelength has a higher maximum output of the laser light than the laser light with a short wavelength, but has a low laser absorption rate for workpieces made of high-reflectivity materials. Therefore, with the laser light with a long wavelength, it is difficult to keep the melting amount of the workpiece constant, and there is a risk of deterioration of the processing quality.

[0006] The present invention has been made in view of such points, and its object is to improve the processing quality and processing speed of the workpiece.

Means for Solving the Problems

[0007] The first invention is a laser processing method for processing a workpiece by emitting laser light, wherein the workpiece has at least a first processing target portion and a second processing target portion located away from the first processing target portion, the laser light includes a first laser light and a second laser light having a longer wavelength than the first laser light, and the method comprises a first step of emitting the first laser light to the first processing target portion, a second step of emitting the second laser light to the first processing target portion from which the first laser light was emitted, a third step of emitting the first laser light to the second processing target portion, and a fourth step of emitting the second laser light to the second processing target portion from which the first laser light was emitted.

[0008] In the first invention, the workpiece has a first workpiece and a second workpiece. The second workpiece is located away from the first workpiece. In the first step, a first laser beam is emitted towards the first workpiece. In the second step, a second laser beam is emitted towards the first workpiece from which the first laser beam was emitted. In the third step, a first laser beam is emitted towards the second workpiece. In the fourth step, a second laser beam is emitted towards the second workpiece from which the first laser beam was emitted.

[0009] In this way, by preheating the workpiece to be processed with the first laser beam and then emitting the second laser beam, the processing quality and processing speed of the workpiece can be improved.

[0010] Specifically, short-wavelength first laser light (e.g., blue laser light of 600 nm or less) has a high laser absorption rate for workpieces made of highly reflective materials such as copper, but its maximum laser output is low. On the other hand, long-wavelength second laser light (e.g., infrared laser light of 800 nm or more) has a low laser absorption rate for workpieces made of highly reflective materials, but its maximum laser output is high.

[0011] Therefore, by emitting the first laser beam onto the surface of the workpiece in advance, surface modification such as oxidation and preheating of the workpiece are performed. Then, by emitting the second laser beam onto the parts of the workpiece that have undergone surface modification and preheating, the second laser beam becomes more easily absorbed by the workpiece.

[0012] The second invention is characterized in that, in the first invention, the third step is performed while the second step is being performed.

[0013] In the second invention, the processing time for the workpiece can be shortened by preheating the second workpiece, which is to be processed next, with the first laser beam while the first workpiece is being processed with the second laser beam.

[0014] The third invention is characterized in that, in the first or second invention, the first workpiece and the second workpiece are arranged adjacent to each other, the second laser beam is emitted in the first workpiece near the second workpiece in the second step, and the second laser beam is emitted in the second workpiece near the first workpiece in the fourth step.

[0015] In the third invention, by emitting laser light to the first and second workpieces at positions close to the other side, the molten workpieces flow toward the other side, making it easier for them to join together.

[0016] The fourth invention is characterized in that, in the first invention, the first step involves moving the emission position of the first laser beam along a predetermined movement trajectory, and in the second step, the emission position of the second laser beam along the movement trajectory of the first laser beam.

[0017] In the fourth invention, the processing quality of the workpiece can be improved by emitting a second laser beam before the temperature of the area preheated by the first laser beam decreases. [Effects of the Invention]

[0018] According to the present invention, the processing quality and processing speed of the workpiece can be improved.

Brief Description of the Drawings

[0019] [Figure 1] It is a side view showing a schematic configuration of a laser processing apparatus according to Embodiment 1. [Figure 2] It is a graph showing the relationship between the wavelength and reflectivity of laser light. [Figure 3A] It is a plan view showing a state where the first laser light is emitted to the first processing target portion. [Figure 3B] It is a plan view showing a state where the first laser light is emitted to the second processing target portion while the second laser light is emitted to the first processing target portion. [Figure 3C] It is a plan view showing a state where the first laser light is emitted to the third processing target portion while the second laser light is emitted to the second processing target portion. [Figure 3D] It is a plan view showing a state where the first laser light is emitted to the fourth processing target portion while the second laser light is emitted to the third processing target portion. [Figure 3E] It is a plan view showing a state where the first laser light is emitted to the fifth processing target portion while the second laser light is emitted to the fourth processing target portion. [Figure 3F] It is a plan view showing a state where the first laser light is emitted to the sixth processing target portion while the second laser light is emitted to the fifth processing target portion. [Figure 3G] It is a plan view showing a state where the second laser light is emitted to the sixth processing target portion. [Figure 3H] It is a plan view showing the state of the workpiece after laser processing. [Figure 4A] In the laser processing apparatus according to a modification of Embodiment 1, it is a plan view showing a state where the first laser light is emitted to the first processing target portion. [Figure 4B] It is a plan view showing a state where the first laser light is emitted to the second processing target portion while the second laser light is emitted to the first processing target portion. [Figure 4C]This is a plan view showing the state in which the first laser beam is emitted to the third processing target, while the second laser beam is emitted to the second processing target. [Figure 4D] This is a plan view showing the state in which the first laser beam is emitted to the fourth processing target, while the second laser beam is emitted to the third processing target. [Figure 5A] This is a perspective view showing the laser processing apparatus according to this second embodiment, with the first laser beam emitted to the first workpiece. [Figure 5B] This is a perspective view showing the state in which the first laser beam is emitted to the second processing target while the second laser beam is emitted to the first processing target. [Figure 5C] This is a perspective view showing the state in which the first laser beam is emitted to the third processing target, while the second laser beam is emitted to the second processing target. [Figure 5D] This is a perspective view showing the second laser beam being emitted onto the third processing target. [Figure 5E] This is a perspective view showing the state of the workpiece after laser processing. [Figure 6A] This is a perspective view showing the laser processing apparatus according to this third embodiment, in which the emission positions of the first laser beam and the second laser beam have been moved within the area of ​​the first processing target. [Figure 6B] This is a perspective view showing the state in which the emission positions of the first laser beam and the second laser beam have been moved within the area of ​​the second processing target. [Figure 6C] This is a perspective view showing the state in which the emission positions of the first and second laser beams have been moved within the area of ​​the third processing target. [Figure 6D] This is a perspective view showing the state of the workpiece after laser processing. [Figure 7] This is a perspective view showing the movement trajectory of the laser beam emission position in Modification 1 of this embodiment 3. [Figure 8] This is a perspective view showing the movement trajectory of the laser beam emission position in a modified example 2 of this embodiment 3. [Figure 9] This is a perspective view showing the movement trajectory of the laser beam emission position in a modified example 3 of this embodiment 3. [Modes for carrying out the invention]

[0020] Embodiments of the present invention will be described below with reference to the drawings. The following description of preferred embodiments is essentially illustrative and is not intended to limit the present invention, its applications, or its uses.

[0021] Embodiment 1 As shown in Figure 1, the laser processing apparatus 1 comprises a first laser oscillator 11, a second laser oscillator 12, a first transmission fiber 15, a second transmission fiber 16, a laser processing head 20, a robot 2, and a control unit 5.

[0022] The first laser oscillator 11 outputs a first laser beam L1 based on a command from the control unit 5. The first laser beam L1 is a short-wavelength laser beam. The short-wavelength first laser beam L1 is a blue laser beam or a green laser beam with a wavelength of 600 nm or less (for example, 266 nm to 600 nm).

[0023] The first laser oscillator 11 and the laser processing head 20 are connected by a first transmission fiber 15. The first laser beam L1 is transmitted from the first laser oscillator 11 to the laser processing head 20 via the first transmission fiber 15.

[0024] The second laser oscillator 12 outputs a second laser beam L2 based on a command from the control unit 5. The second laser beam L2 is a long-wavelength laser beam with a longer wavelength than the first laser beam L1. The long-wavelength second laser beam L2 is an infrared laser beam with a wavelength of 800 nm or more (for example, around 800 nm to 16000 nm).

[0025] The second laser oscillator 12 and the laser processing head 20 are connected by a second transmission fiber 16. The second laser light L2 is transmitted from the second laser oscillator 12 to the laser processing head 20 via the second transmission fiber 16.

[0026] The laser processing head 20 emits the first laser beam L1 and the second laser beam L2, which are incident from the first transmission fiber 15 and the second transmission fiber 16, to the workpiece W.

[0027] The laser processing head 20 includes a first collimating lens 21, a second collimating lens 22, a first mirror 23, a first adjustment mechanism 24, a second adjustment mechanism 25, a dichroic mirror 26, and an fθ lens 27.

[0028] The first collimating lens 21 parallelizes the first laser beam L1 emitted from the exit end of the first transmission fiber 15. The second collimating lens 22 parallelizes the second laser beam L2 emitted from the exit end of the second transmission fiber 16. The first mirror 23 reflects the first laser beam L1 parallelized by the first collimating lens 21 and guides it to the first adjustment mechanism 24, which has a variable mirror angle so that the emission position of the first laser beam L1 relative to the workpiece W can be changed.

[0029] Furthermore, by moving the first collimating lens 21 and the second collimating lens 22 in the optical axis direction, the beam diameters of the first laser beam L1 and the second laser beam L2 can be increased or decreased.

[0030] The first adjustment mechanism 24 is composed of a two-axis MEMS (Micro Electro Mechanical Systems) mirror. The first adjustment mechanism 24 further reflects the first laser beam L1 reflected by the first mirror 23 and guides it to the dichroic mirror 26. The first adjustment mechanism 24 changes the incident position of the first laser beam L1 on the dichroic mirror 26 by changing the angle of the mirror in the two axes. The first adjustment mechanism 24 may also be configured using a two-axis galvanometer (galvanometer mirror).

[0031] The second adjustment mechanism 25 is composed of a two-axis MEMS (Micro Electro Mechanical Systems) mirror. The second adjustment mechanism 25 reflects the second laser beam L2, which has been parallelized by the second collimating lens 22, and guides it to the dichroic mirror 26. The second adjustment mechanism 25 changes the incident position of the second laser beam L2 on the dichroic mirror 26 by changing the angle of the mirror in the two axes. The second adjustment mechanism 25 may also be configured using a two-axis galvanometer (galvano mirror).

[0032] The dichroic mirror 26 transmits the second laser beam L2 and reflects the first laser beam L1. The dichroic mirror 26 superimposes the first laser beam L1 and the second laser beam L2 and guides them to the fθ lens 27.

[0033] The fθ lens 27 focuses the first laser beam L1 and the second laser beam L2 at their respective incident positions so that they become beams that are incident perpendicularly to the surface (image plane) of the workpiece W. The first laser beam L1 and the second laser beam L2 focused by the fθ lens 27 are emitted to the workpiece W as parallel light (in other words, parallel light whose principal rays are parallel to the optical axis).

[0034] Here, the incident positions of the first laser beam L1 and the second laser beam L2 on the fθ lens 27 are moved by changing the angles of the first adjustment mechanism 24 and the second adjustment mechanism 25, respectively. This allows the first adjustment mechanism 24 and the second adjustment mechanism 25 to change the emission positions of the first laser beam L1 and the second laser beam L2 on the workpiece W.

[0035] Robot 2 has a robotic arm 3. A laser processing head 20 is attached to the tip of the robotic arm 3. The robotic arm 3 has multiple joints 4.

[0036] Based on commands from the control unit 5, the robot 2 moves the laser processing head 20 along a predetermined processing direction, changing the position of the laser processing head 20 relative to the workpiece W. This changes the positions of the first laser beam L1 and the second laser beam L2 relative to the workpiece W, thereby performing laser processing.

[0037] The control unit 5 is connected to the first laser oscillator 11, the second laser oscillator 12, the laser processing head 20, and the robot 2. The control unit 5 controls the operation of the first laser oscillator 11, the second laser oscillator 12, the laser processing head 20, and the robot 2.

[0038] In addition to controlling the movement speed of the laser processing head 20, the control unit 5 also has functions to control the start and stop of the output of the first laser beam L1 and the second laser beam L2, and the output intensity of the first laser beam L1 and the second laser beam L2. Although the control unit 5 is shown as a single unit here, it may be configured as multiple units.

[0039] The workpiece W has multiple pin members extending in the vertical direction. In the example shown in Figure 1, there are six pin members. At the upper ends of the six pin members, there are first processing target parts w1, second processing target parts w2, third processing target parts w3, fourth processing target parts w4, fifth processing target parts w5, and sixth processing target parts w6, respectively. Note that the number of processing target parts is merely an example and is not limited to this.

[0040] The first processing target part w1, the third processing target part w3, and the fifth processing target part w5 are arranged with a gap between them along the welding direction. The second processing target part w2, the fourth processing target part w4, and the sixth processing target part w6 are arranged with a gap between them along the welding direction.

[0041] The first workpiece w1 and the second workpiece w2 are positioned with a gap between them in an intersecting direction that intersects the welding direction. The third workpiece w3 and the fourth workpiece w4 are positioned with a gap between them in an intersecting direction. The fifth workpiece w5 and the sixth workpiece w6 are positioned with a gap between them in an intersecting direction.

[0042] The laser processing device 1 welds the first processing target w1 and the second processing target w2. The laser processing device 1 welds the third processing target w3 and the fourth processing target w4. The laser processing device 1 welds the fifth processing target w5 and the sixth processing target w6.

[0043] Workpiece W is composed of a highly reflective material with low laser absorption. Specifically, as shown in Figure 2, the reflectivity of laser light differs depending on the material of workpiece W. For example, using infrared laser light with a long wavelength of 800 nm or more as a reference, copper (Cu), aluminum (Al), gold (Au), and silver (Ag) have a higher reflectivity (%) at the wavelength of laser light compared to iron (Fe), meaning they are highly reflective materials with low laser absorption. On the other hand, iron (Fe) has a relatively low reflectivity (%) at the wavelength of laser light, meaning it is a low-reflectivity material with high laser absorption.

[0044] Therefore, in this embodiment, the workpiece W is made of copper, which is a highly reflective material with low laser absorption. Alternatively, the workpiece W may be made of gold or silver.

[0045] <Operation of the laser processing machine> Incidentally, the short-wavelength first laser beam L1 has a high laser absorption rate for workpieces W made of highly reflective materials such as copper, but the maximum output of the laser beam is low, resulting in a slow processing speed.

[0046] On the other hand, the long-wavelength second laser beam L2 has a higher maximum output than the short-wavelength first laser beam L1, but it has a lower laser absorption rate for the highly reflective workpiece W. Therefore, it is difficult to maintain a constant penetration rate of the workpiece W with the long-wavelength second laser beam L2, which may lead to a decrease in processing quality.

[0047] Therefore, in this embodiment, the processing quality and processing speed of the workpiece W can be improved by devising the method of emitting the first laser beam L1 and the second laser beam L2.

[0048] As shown in Figure 3A, the laser processing apparatus 1 performs a first step of emitting a short-wavelength first laser beam L1 onto the first processing target w1 of the workpiece W. The first laser beam L1 is emitted to the center of the first processing target w1 in a plan view. In the first step, the short-wavelength first laser beam L1 removes any coatings or adhesives adhering to the first processing target w1, and also preheats the first processing target w1.

[0049] Specifically, the laser processing head 20 emits a first laser beam L1, which has a high laser absorption rate for highly reflective materials, onto the surface of the workpiece W in advance, thereby performing surface modification such as oxidizing the surface of the workpiece W or partially melting the surface of the workpiece W beforehand.

[0050] As shown in Figure 3B, the laser processing apparatus 1 performs a second step in which it emits a second laser beam L2 with high power density and long wavelength to the first processing target w1 from which the first laser beam L1 was emitted. The second laser beam L2 with long wavelength is emitted to the center of the first processing target w1 in a plan view. In the second step, a molten portion 31 is formed by the melting of a part of the first processing target w1 by the second laser beam L2 with long wavelength.

[0051] The laser processing apparatus 1 performs a third step in which it emits a short-wavelength first laser beam L1 onto the second workpiece w2. In the third step, the short-wavelength first laser beam L1 removes any coatings or adhesives adhering to the second workpiece w2, and also preheats the second workpiece w2.

[0052] Here, it is preferable to perform the third step while the second step is being carried out. In this way, while the first workpiece w1 is being processed with the long-wavelength second laser beam L2, the second workpiece w2 to be processed next is preheated with the short-wavelength first laser beam L1, thereby shortening the processing time of the workpiece W.

[0053] As shown in Figure 3C, the laser processing apparatus 1 performs a fourth step in which it emits a long-wavelength second laser beam L2 to the second processing target w2 from which a short-wavelength first laser beam L1 has been emitted. In the fourth step, a part of the second processing target w2 melts due to the long-wavelength second laser beam L2, forming a molten portion 31. The molten portion 31 of the first processing target w1 and the molten portion 31 of the second processing target w2 flow toward each other, and the molten portions 31 become one.

[0054] In this way, by preheating the part of the workpiece to be processed with a short-wavelength first laser beam L1 and then emitting a long-wavelength second laser beam L2, the processing quality and processing speed of the workpiece W can be improved.

[0055] The laser processing apparatus 1 performs a fifth step in which it emits a short-wavelength first laser beam L1 onto the third workpiece w3. In the fifth step, the short-wavelength first laser beam L1 removes any coatings or adhesives adhering to the third workpiece w3, and also preheats the third workpiece w3. The fifth step is performed while the fourth step is in progress.

[0056] As shown in Figure 3D, the molten portion 31 solidifies to form the joint portion 32. The first part to be processed w1 and the second part to be processed w2 are joined together by the joint portion 32.

[0057] The process of preheating the remaining parts to be processed with a short-wavelength first laser beam L1 and then melting them with a long-wavelength second laser beam L2 is repeated in the same manner.

[0058] Specifically, the laser processing apparatus 1 emits a long-wavelength second laser beam L2 to the third processing target w3 from which a short-wavelength first laser beam L1 has been emitted. The laser processing apparatus 1 also emits a short-wavelength first laser beam L1 to the fourth processing target w4.

[0059] As shown in Figure 3E, the laser processing apparatus 1 emits a long-wavelength second laser beam L2 to the fourth processing target w4 from which a short-wavelength first laser beam L1 has been emitted. The laser processing apparatus 1 also emits a short-wavelength first laser beam L1 to the fifth processing target w5.

[0060] The molten portion 31 of the third processing target w3 and the molten portion 31 of the fourth processing target w4 flow toward the other side, and the molten portions 31 become one.

[0061] As shown in Figure 3F, the molten portion 31 solidifies to form the joint portion 32. The third processing target portion w3 and the fourth processing target portion w4 are joined by the joint portion 32. The laser processing apparatus 1 emits a long-wavelength second laser beam L2 to the fifth processing target portion w5 from which a short-wavelength first laser beam L1 has been emitted. The laser processing apparatus 1 emits a short-wavelength first laser beam L1 to the sixth processing target portion w6.

[0062] As shown in Figure 3G, the laser processing apparatus 1 emits a long-wavelength second laser beam L2 to the fifth processing target w5 from which a short-wavelength first laser beam L1 has been emitted. The molten portion 31 of the fifth processing target w5 and the molten portion 31 of the sixth processing target w6 flow toward each other, and the molten portions 31 become one.

[0063] As shown in Figure 3H, the joint 32 is formed when the molten portion 31 solidifies. The fifth processing target portion w5 and the sixth processing target portion w6 are joined by the joint 32.

[0064] -Modified form of Embodiment 1- As shown in Figure 4A, the laser processing apparatus 1 performs a first step of emitting a short-wavelength first laser beam L1 onto the first processing target portion w1 of the workpiece W. The first laser beam L1 is emitted from a position closer to the second processing target portion w2 (downward) than the center line in the intersection direction (up and down direction in Figure 4A) that intersects with the welding direction of the first processing target portion w1 in a plan view.

[0065] In the first step, a short-wavelength first laser beam L1 removes any coatings or adhesives adhering to the first workpiece w1, and preheats the portion of the first workpiece w1 that is close to the second workpiece w2.

[0066] As shown in Figure 4B, the laser processing apparatus 1 performs a second step in which it emits a long-wavelength second laser beam L2 to the first processing target w1 from which a short-wavelength first laser beam L1 has been emitted. The long-wavelength second laser beam L2 is emitted from a position closer to (downward) the second processing target w2 than the center line in the intersecting direction (up and down direction in Figure 4B) of the first processing target w1 in a plan view. In the second step, a molten portion 31 is formed by the melting of a part of the first processing target w1 by the long-wavelength second laser beam L2.

[0067] The laser processing apparatus 1 performs a third step in which it emits a short-wavelength first laser beam L1 onto the second workpiece w2. The short-wavelength first laser beam L1 is emitted from a position closer to (upper) the first workpiece w1 than the center line in the intersecting direction (up and down direction in Figure 4B) of the second workpiece w2 when viewed from above.

[0068] In the third step, the coating and adhesive adhering to the second workpiece w2 are removed by the first short-wavelength laser beam L1, and the portion of the second workpiece w2 closest to the first workpiece w1 is preheated.

[0069] As shown in Figure 4C, the laser processing apparatus 1 performs a fourth step in which it emits a long-wavelength second laser beam L2 to the second processing target w2 from which a short-wavelength first laser beam L1 has been emitted. The long-wavelength second laser beam L2 is emitted from a position closer to (upper) the first processing target w1 than the center line in the intersecting direction (up and down direction in Figure 4C) of the second processing target w2 in a plan view.

[0070] In the fourth step, a molten portion 31 is formed when a part of the second processing target w2 is melted by the long-wavelength second laser beam L2.

[0071] Here, in the first processing target part w1 and the second processing target part w2, the first laser beam L1 and the second laser beam L2 are emitted at positions close to the other side, respectively. As a result, the molten part 31 of the first processing target part w1 and the molten part 31 of the second processing target part w2 flow more easily toward the other side, and the molten parts 31 become one.

[0072] While the fourth process is being performed, the laser processing apparatus 1 emits a short-wavelength first laser beam L1 towards the third processing target w3. The short-wavelength first laser beam L1 is emitted from a position closer to the fourth processing target w4 (downward) than the center line in the intersecting direction (up and down direction in Figure 4C) of the third processing target w3 in a plan view.

[0073] As shown in Figure 4D, the joint 32 is formed when the molten portion 31 solidifies. The first part to be processed w1 and the second part to be processed w2 are joined together by the joint 32.

[0074] The process of preheating the remaining parts to be processed with a short-wavelength first laser beam L1 and then melting them with a long-wavelength second laser beam L2 is repeated in the same manner.

[0075] Embodiment 2 In the following description, the same reference numerals are used for parts that are the same as those in Embodiment 1, and only the differences will be described.

[0076] As shown in Figure 5A, the workpiece W has two plate-shaped members that are overlapped. The workpiece W is provided with a first processing area w1, a second processing area w2, and a third processing area w3. The first processing area w1, the second processing area w2, and the third processing area w3 are spaced apart in the welding direction. Note that the number of processing areas is merely an example and is not limited to this.

[0077] As shown in Figure 5A, the laser processing apparatus 1 performs a first step of emitting a short-wavelength first laser beam L1 onto the first processing target w1 of the workpiece W. In the first step, the first processing target w1 is preheated by the short-wavelength first laser beam L1.

[0078] As shown in Figure 5B, the laser processing apparatus 1 performs a second step in which it emits a long-wavelength second laser beam L2 to the first processing target w1 from which a short-wavelength first laser beam L1 has been emitted. In the second step, a molten portion 31 is formed when a part of the first processing target w1 is melted by the long-wavelength second laser beam L2.

[0079] The laser processing apparatus 1 performs a third step in which it emits a short-wavelength first laser beam L1 onto the second workpiece w2. In the third step, the second workpiece w2 is preheated by the short-wavelength first laser beam L1. The third step is performed while the second step is in progress.

[0080] As shown in Figure 5C, a joint 32 is formed in the first workpiece w1 when the molten portion 31 solidifies. The two plate-shaped members of the workpiece W are joined at the joint 32.

[0081] The laser processing apparatus 1 performs a fourth step in which it emits a long-wavelength second laser beam L2 to the second processing target w2 from which a short-wavelength first laser beam L1 has been emitted. In the fourth step, a molten portion 31 is formed when a part of the second processing target w2 is melted by the long-wavelength second laser beam L2.

[0082] The laser processing apparatus 1 performs a fifth step in which it emits a short-wavelength first laser beam L1 onto the third workpiece w3. In the fifth step, the third workpiece w3 is preheated by the short-wavelength first laser beam L1. The fifth step is performed while the fourth step is in progress.

[0083] As shown in Figure 5D, a joint 32 is formed in the second processing target w2 when the molten portion 31 solidifies. The two plate-shaped members of the workpiece W are joined at the joint 32.

[0084] The laser processing apparatus 1 performs a sixth step in which it emits a long-wavelength second laser beam L2 to the third processing target w3 from which a short-wavelength first laser beam L1 has been emitted. In the sixth step, a molten portion 31 is formed when a part of the third processing target w3 melts due to the long-wavelength second laser beam L2.

[0085] As shown in Figure 5E, a joint 32 is formed in the third workpiece w3 when the molten portion 31 solidifies. The two plate-shaped members of the workpiece W are joined at the joint 32.

[0086] Embodiment 3 In the following description, the same reference numerals are used for parts that are the same as those in Embodiment 2, and only the differences will be described.

[0087] As shown in Figure 6A, the laser processing apparatus 1 performs a first step of emitting a short-wavelength first laser beam L1 to the first workpiece w1. In the first step, the emission position of the short-wavelength first laser beam L1 is moved along the welding direction within the area of ​​the first workpiece w1. In the first step, the first workpiece w1 is preheated by the short-wavelength first laser beam L1.

[0088] The laser processing apparatus 1 performs a second step in which it emits a long-wavelength second laser beam L2 to a first workpiece w1 from which a short-wavelength first laser beam L1 has been emitted. In the second step, the emission position of the long-wavelength second laser beam L2 is moved along the movement trajectory of the short-wavelength first laser beam L1. Specifically, within the area of ​​the first workpiece w1, the emission position of the long-wavelength second laser beam L2 is moved along the welding direction. In the second step, a part of the first workpiece w1 is melted by the long-wavelength second laser beam L2, forming a molten portion 31 that extends in the welding direction.

[0089] The first and second processes are performed simultaneously within the region of the first workpiece w1. The short-wavelength first laser beam L1 is emitted ahead of the long-wavelength second laser beam L2 in the welding direction.

[0090] As shown in Figure 6B, a joint 32 is formed in the first workpiece w1 when the molten portion 31 solidifies. The two plate-shaped members of the workpiece W are joined at the joint 32.

[0091] The laser processing apparatus 1 performs a third step in which it emits a short-wavelength first laser beam L1 to the second workpiece w2. In the third step, the emission position of the short-wavelength first laser beam L1 is moved along the welding direction within the area of ​​the second workpiece w2. In the third step, the second workpiece w2 is preheated by the short-wavelength first laser beam L1.

[0092] The laser processing apparatus 1 performs a fourth step in which it emits a long-wavelength second laser beam L2 to the second workpiece w2 from which a short-wavelength first laser beam L1 has been emitted. In the fourth step, the emission position of the long-wavelength second laser beam L2 is moved along the movement trajectory of the short-wavelength first laser beam L1. In the fourth step, a part of the second workpiece w2 is melted by the long-wavelength second laser beam L2, forming a molten portion 31 that extends along the welding direction.

[0093] The third and fourth steps are performed simultaneously within the region of the second workpiece w2. The short-wavelength first laser beam L1 is emitted ahead of the long-wavelength second laser beam L2 in the welding direction.

[0094] As shown in Figure 6C, a joint 32 is formed in the second workpiece w2 when the molten portion 31 solidifies. The two plate-shaped members of the workpiece W are joined at the joint 32.

[0095] The laser processing apparatus 1 performs a fifth step in which it emits a short-wavelength first laser beam L1 to the third workpiece w3. In the fifth step, the emission position of the short-wavelength first laser beam L1 is moved along the welding direction within the area of ​​the third workpiece w3. In the fifth step, the third workpiece w3 is preheated by the short-wavelength first laser beam L1.

[0096] The laser processing apparatus 1 performs a sixth step in which it emits a long-wavelength second laser beam L2 to the third workpiece w3 from which a short-wavelength first laser beam L1 has been emitted. In the sixth step, the emission position of the long-wavelength second laser beam L2 is moved along the movement trajectory of the short-wavelength first laser beam L1. In the sixth step, a part of the third workpiece w3 is melted by the long-wavelength second laser beam L2, forming a molten portion 31 that extends along the welding direction.

[0097] Steps 5 and 6 are performed simultaneously within the region of the third workpiece w3. The short-wavelength first laser beam L1 is emitted ahead of the long-wavelength second laser beam L2 in the welding direction.

[0098] As shown in Figure 6D, a joint 32 is formed in the third workpiece w3 when the molten portion 31 solidifies. The two plate-shaped members of the workpiece W are joined at the joint 32.

[0099] In this way, by moving the emission position of the long-wavelength second laser beam L2 along the movement trajectory of the short-wavelength first laser beam L1, and emitting the long-wavelength second laser beam L2 before the temperature of the area preheated by the short-wavelength first laser beam L1 decreases, the processing quality of the workpiece W can be improved.

[0100] -Modification 1 of Embodiment 3- As shown in Figure 7, the laser processing apparatus 1 moves the emission position of the short-wavelength first laser beam L1 along a predetermined movement trajectory within the area of ​​the part to be processed. In the example shown in Figure 7, the laser processing apparatus 1 moves the emission position of the short-wavelength first laser beam L1 in a spiral shape within the area of ​​the first part to be processed w1.

[0101] Specifically, in a plan view, the center of the first workpiece w1 is defined as the laser start position 35, and the position radially outward from the laser start position 35 is defined as the laser end position 36. Then, between the laser start position 35 and the laser end position 36, the emission position of the short-wavelength first laser beam L1 is moved in a spiral clockwise direction so that it gradually spreads radially outward (see the dashed line in Figure 7).

[0102] The laser processing apparatus 1 moves the emission position of the short-wavelength first laser beam L1 along the movement trajectory of the short-wavelength first laser beam L1 within the area of ​​the first workpiece w1. Specifically, the short-wavelength first laser beam L1 is emitted ahead of the long-wavelength second laser beam L2 in the movement trajectory. The emission position of the long-wavelength second laser beam L2 moves spirally in a clockwise direction from the laser start position 35 to the laser end position 36 along the spiral movement trajectory of the short-wavelength first laser beam L1.

[0103] This allows the first laser beam L1 and the second laser beam L2 to be emitted over a wide area of ​​the first processing target part w1.

[0104] In the example shown in Figure 7, the movement trajectories of the first laser beam L1 and the second laser beam L2 within the region of the first processing target w1 were explained, but the same procedure can be followed for other processing target areas, by emitting the first laser beam L1 and the second laser beam.

[0105] -Modification 2 of Embodiment 3- As shown in Figure 8, the laser processing apparatus 1 moves the emission position of the short-wavelength first laser beam L1 along a predetermined movement trajectory within the area of ​​the part to be processed. In the example shown in Figure 8, the laser processing apparatus 1 moves the emission position of the short-wavelength first laser beam L1 in a square spiral shape within the area of ​​the first part to be processed w1.

[0106] Specifically, in a plan view, the laser start position 35 is near the center of the first processing target w1, and the laser end position 36 is at the lower left corner of the first processing target w1 in Figure 8. Then, between the laser start position 35 and the laser end position 36, the emission position of the short-wavelength first laser beam L1 is moved clockwise in a square spiral pattern so that it gradually spreads outwards (see the dashed line in Figure 8).

[0107] The laser processing apparatus 1 moves the emission position of the short-wavelength first laser beam L1 along the movement trajectory of the short-wavelength first laser beam L1 within the area of ​​the first workpiece w1. Specifically, the short-wavelength first laser beam L1 is emitted ahead of the long-wavelength second laser beam L2 in the movement trajectory. The emission position of the long-wavelength second laser beam L2 moves in a clockwise direction in a square spiral along the square spiral movement trajectory of the short-wavelength first laser beam L1, from the laser start position 35 to the laser end position 36.

[0108] This allows the first laser beam L1 and the second laser beam L2 to be emitted over a wide area of ​​the first processing target part w1.

[0109] -Modification 3 of Embodiment 3- As shown in Figure 9, the laser processing apparatus 1 moves the emission position of the first laser beam L1 along a predetermined movement trajectory within the area of ​​the part to be processed. In the example shown in Figure 9, the laser processing apparatus 1 moves the emission position of the short-wavelength first laser beam L1 in a zigzag pattern within the area of ​​the first part to be processed w1.

[0110] Specifically, in a plan view, the upper right corner of the first processing target part w1 in Figure 9 is designated as the laser start position 35, and the lower left corner in Figure 9 is designated as the laser end position 36. Then, the emission position of the short-wavelength first laser beam L1 is moved in a zigzag pattern between the laser start position 35 and the laser end position 36 (see the dashed line in Figure 9).

[0111] The laser processing apparatus 1 moves the emission position of the short-wavelength first laser beam L1 along the movement trajectory of the short-wavelength first laser beam L1 within the area of ​​the first workpiece w1. Specifically, the short-wavelength first laser beam L1 is emitted ahead of the long-wavelength second laser beam L2 in the movement trajectory. The emission position of the long-wavelength second laser beam L2 moves in a zigzag pattern from the laser start position 35 to the laser end position 36 along the zigzag movement trajectory of the short-wavelength first laser beam L1.

[0112] This allows the first laser beam L1 and the second laser beam L2 to be emitted over a wide area of ​​the first processing target part w1.

[0113] Other embodiments The above embodiment may also have the following configuration.

[0114] In this embodiment, the laser processing head 20 is moved by the robot 2 to change its position relative to the workpiece W, but the embodiment is not limited to this. For example, the workpiece W may be mounted on a moving table (not shown), and the laser processing head 20 may be moved relative to the workpiece W.

[0115] In this embodiment, a configuration has been described in which a first laser beam L1 and a second laser beam L2 are emitted from a single laser processing head 20, but the embodiment is not limited to this configuration. For example, a configuration in which a laser processing head that emits the first laser beam L1 and a laser processing head that emits the second laser beam L2 are provided separately may also be used. [Industrial applicability]

[0116] As described above, the present invention is extremely useful and has high industrial applicability because it provides highly practical effects such as improving the machining quality and machining speed of the workpiece. [Explanation of Symbols]

[0117] 1. Laser processing device 11. First Laser Oscillator 12. Second laser oscillator 20 Laser processing heads L1 First laser beam L2 Second laser beam Double job w1 First part to be processed w2 Second part to be processed

Claims

1. A laser processing method that processes a workpiece by emitting laser light, The workpiece has at least a first part to be processed and a second part to be processed that is located away from the first part to be processed and is different from the first part to be processed. The laser light includes a first laser light and a second laser light having a longer wavelength than the first laser light. A first step of emitting the first laser beam to the first part to be processed, A second step involves emitting a second laser beam to the first workpiece from which the first laser beam has been emitted, A third step of emitting the first laser beam to the second part to be processed, The process includes a fourth step of emitting a second laser beam to the second workpiece from which the first laser beam has been emitted. A laser processing method characterized by the following features.

2. In claim 1, While the second step is being performed, the third step is performed. A laser processing method characterized by the following features.

3. In claim 1 or 2, The first workpiece and the second workpiece are arranged adjacent to each other. In the second step, the second laser beam is emitted from the first workpiece closer to the second workpiece. In the fourth step, the second laser beam is emitted from the second workpiece at a position closer to the first workpiece. A laser processing method characterized by the following features.

4. In claim 1, In the first step, the emission position of the first laser beam is moved along a predetermined movement trajectory. In the second step, the emission position of the second laser beam is moved along the movement trajectory of the first laser beam. A laser processing method characterized by the following features.

Images