CN113478074A

CN113478074A - Laser device

Info

Publication number: CN113478074A
Application number: CN202010186805.5A
Authority: CN
Inventors: 千国达朗; 牛增强; 陈国宁; 卢国杰; 韩金龙
Original assignee: United Winners Laser Co Ltd
Current assignee: United Winners Laser Co Ltd
Priority date: 2020-03-17
Filing date: 2020-03-17
Publication date: 2021-10-08
Also published as: WO2021184513A1

Abstract

The invention discloses a laser device which is characterized by comprising a single-fiber-core optical fiber and a lens barrel used for condensing emergent light from the single-fiber-core optical fiber to realize keyhole-type and/or heat conduction type hybrid welding, wherein a hollow spherical mirror, a collimating lens and a condensing lens are sequentially arranged in the lens barrel and the single-fiber-core optical fiber on the same optical axis, the hollow spherical mirror is arranged in the lens barrel and positioned between an optical fiber outlet and the collimating lens, the hollow spherical mirror is longer than the focusing distance of the condensing lens, and the hollow diameter of the hollow spherical mirror is arranged in a light beam emitted by the optical fiber. The present invention is also characterized in that it can flexibly cope with fiber lasers of various companies, can perform single-mode transmission, and can realize a spoon-hole type and heat-conduction type hybrid welding method using a simple single-fiber core fiber with high endurance.

Description

Laser device

[ technical field ] A method for producing a semiconductor device

The present invention relates to the field of laser processing, and more particularly to a laser device for performing processing such as laser welding.

[ background of the invention ]

In recent years, as a means for eliminating welding defects such as spatters, blowholes, cracks, and the like and achieving high-quality welding, a hybrid welding system in which keyhole welding and heat conduction welding are superimposed has been used particularly in mass production of on-vehicle batteries.

In order to realize the hybrid welding method of the keyhole type and the heat conduction type, it is possible to realize by overlapping a high-brightness focused spot on a small diameter of keyhole welding and a large-diameter low-brightness focused spot for preheating the periphery thereof.

As a hybrid welding method for easily realizing a keyhole type and a heat conduction type with one optical fiber, for example, as shown in fig. 4 in patent document, a method is put into practical use in which an annular core is provided around a core at the center of an optical fiber, and further, in an optical fiber having a cladding at the outer side, laser light emitted from a two-core optical fiber is condensed by being bridged to one of the two cores. However, when performing kilowatt-level hybrid bonding, it is very difficult to produce a dual core as in the patent document, and it is impossible to produce it unless a special optical fiber manufacturer is present.

Further, there is a problem in terms of coupling durability, and there is a problem that single-mode laser transmission with a fiber core diameter of less than 50 μm cannot be performed.

[ summary of the invention ]

In view of the above, the present invention has been made to solve the above problems, and an object of the present invention is to provide a laser apparatus of a simple single-fiber spoon-hole type and heat conduction type hybrid welding system that can flexibly cope with fiber lasers of various companies, can perform single-mode transmission, and is used with high durability.

In order to solve the technical problem, the invention provides a laser welding head for imaging laser emitted from an optical fiber by using a collimating lens and a condensing lens, wherein a hollow convex lens or a hollow concave lens with a longer focal length is inserted in front of the collimating lens, and the hollow part passes through a light beam near the center of the optical fiber and is collimated and focused by the welding head to realize keyhole welding. On the other hand, the light beam far away from the center of the optical fiber penetrates through the hollow convex spherical mirror/concave lens with a long focal length, the focal position is changed, the light beam passes through the hollow part, the focal point deviates, an out-of-focus concentric focusing light spot is obtained on the welding plane, the out-of-focus light spot is larger, heat conduction welding can be achieved, the light spot at the positive focal point is small, and keyhole welding can be achieved. Therefore, keyhole-type + heat conduction-type laser welding is realized.

In the technical scheme, the light beam near the center of the optical fiber passes through the space part of the hollow spherical mirror in front of or behind the collimating lens without damage and is focused on the surface of the workpiece unaffected, and other light beams passing through the curved surface part of the hollow spherical mirror change the angle of the light beam transmitted along the optical axis because of the curved surface of the hollow spherical mirror, and after the light beam is focused, the focal position of the light beam is shifted or moved forwards or backwards relative to the focal position of the central light beam, so that two concentric light spots are obtained on the surface of the workpiece, wherein one light spot is small and has high power density, and the other light spot is large and has low power density. In particular, in the case of a lithium battery for vehicle use, high-quality welding without sputtering and without pores is indispensable for welding iron, aluminum, and copper. The size of the splash and the air holes generated by the new method is much smaller than 50um required by the specification, so that the quality and the yield can be improved.

In addition, by changing the distance between the hollow spherical mirror and the collimating lens, the power ratio of the keyhole to the heat conduction can be adjusted, and the spot diameter for the heat conduction can be finely adjusted, so that higher-quality laser welding can be realized.

Further, since the hollow spherical mirrors having different cavity sizes can be easily replaced, the process condition width can be changed greatly, and welding of various shapes and materials can be performed easily and with high quality.

Further, by using a lens having a flat central portion instead of the hollow spherical mirror, the laser durability can be further improved.

[ description of the drawings ]

Fig. 1 is an overall configuration diagram of a laser device according to the present embodiment;

fig. 2 is a basic configuration diagram of the laser light source according to embodiment 1. Fig. 2(a) is a lens barrel diagram of a convex hollow lens; fig. 2(b) is a luminance distribution diagram of a barrel diagram of the convex hollow lens;

fig. 3 is a basic configuration diagram of the laser light source according to embodiment 1. Fig. 3(a) is a barrel view of a concave hollow lens; FIG. 3(b) is a luminance distribution diagram of a barrel diagram of the concave hollow lens;

FIG. 4 is a schematic view of keyhole + heat conduction hybrid welding;

fig. 5 is a basic configuration diagram of the laser light source according to embodiment 2. Fig. 5(a) is a lens barrel diagram of a convex hollow lens; fig. 5(b) is a luminance distribution diagram of a barrel diagram of the convex hollow lens;

fig. 6 is a basic configuration diagram of the laser light source according to embodiment 2. Fig. 6(a) is a barrel view of a concave hollow lens; fig. 6(b) is a luminance distribution diagram of a barrel diagram of the concave hollow lens;

fig. 7 is a basic configuration diagram of the laser light source according to embodiment 3. Fig. 7(a) is a barrel diagram, and fig. 7(b) is a luminance distribution diagram;

fig. 8 is a basic configuration diagram of the laser light source according to embodiment 4. Fig. 8(a) is a barrel diagram, and fig. 8(b) is a luminance distribution diagram;

fig. 9 shows a comparison between the present embodiment and the prior art.

[ detailed description ] embodiments

The following examples are further illustrative and supplementary to the present invention and do not limit the present invention in any way. The technical scheme of the invention is described in detail in the following with reference to the attached drawings:

[ example 1 ]

Fig. 1 is an overall configuration diagram of a laser device according to the present embodiment. The object 5 to be welded is welded by the hybrid light 4 generated from the lens barrel via the single-core fiber 2 from the fiber laser 1. In the present embodiment, the barrel is a hybrid exit barrel 3, which can be used to condense the exit light from a single-core fiber to achieve keyhole-type and/or heat conduction-type hybrid welding. Fig. 2 is a basic configuration diagram of a laser device according to the first embodiment.

As shown in fig. 2(a), the laser device adds a convex hollow spherical mirror 10 between the optical fiber 2 and the collimator lens 12. Inside the hybrid exit barrel 3, a hollow spherical mirror 10, a collimator lens 12, and a condenser lens 13 are arranged in this order on the same optical axis 11 as the single-core optical fiber 2.

Among the laser light 14 emitted from the single-core optical fiber 2, the laser light 16 passing through the hollow portion 15 of the convex hollow spherical mirror 10 is collimated by the collimator lens 12 and then condensed by the condenser lens 13, and a high-brightness focal point 20 satisfying keyhole welding can be obtained at the condensing point 17.

For example, when the coupling ratio of the

lenses

12, 13 is f 150: if f100 is the core diameter of the single-core optical fiber 2 of 20 μm, the fine high-brightness spot 20 of theoretically 20 μm × 100/150 — 13.3 μm can be obtained, and therefore, extremely sharp keyhole welding can be performed.

On the other hand, the laser light 16 that has passed through the convex lens portion 18 of the non-hollow portion of the convex hollow spherical mirror 10 passes through the collimator lens 12, then passes through the collimator lens 12, and then is weakly changed in incident angle with respect to the condenser lens 13 by the convex lens, and the beam is focused at a position 19 slightly before the light collection point 17, and is again diffused after being collected. Therefore, after defocusing, a large low-luminance spot 21 of 100 to 1000 μm can be obtained in a concentric manner with respect to the focused spot 17. The low-brightness spot 21 has an effect of raising and preheating the temperature of the workpiece before the keyhole welding, thereby reducing welding spatter. In addition, the weld has excellent effects of preventing blowholes and cracks caused by slowly cooling the molten pool after keyhole welding.

Fig. 2(b) shows the intensity distribution in which the minute high-luminance dots 20 and the large low-luminance dots 19 are superimposed on the object 5 to be welded.

In addition, since the intensity distribution can be changed by moving the hollow convex spherical mirror 10 forward and backward, the welding conditions can be optimized.

Further, by changing the size of the hollow portion 15, the intensity values of the high-luminance dots 20 and the large low-luminance dots 19 can be adjusted, and the welding conditions can be changed greatly.

In the present embodiment, the intensity value varies with the variation of the high luminance point and the low luminance point, and when the intensity of the high luminance point is 100%, the intensity of the low luminance point is 0%, and when the intensity of the high luminance point is 20%, the intensity of the low luminance point is 80%.

Next, the principle of the spatter-free, void-free welding according to the present embodiment will be described with reference to fig. 4.

For metal 99, keyhole 101 is generated by high intensity laser light 100 generated by high intensity spot 17 illustrated in fig. 4, while a large amount of weld spatter 103 is generated. Molten metal 102 is generated around the keyhole 101, and a bubble of metal vapor is generated at the tip of the keyhole 101, but the metal vapor is cooled and confined in a metal solid on the way to the metal surface, and is referred to as a defect of a blowhole.

On the other hand, by superimposing the low-intensity laser beam 101 generated at the low-intensity spot 21 as described in fig. 4 around the high-intensity laser beam 100, the temperature of the molten metal 102 can be increased by preheating. Therefore, the viscosity is reduced, the opening 105 is enlarged, the metal vapor can be smoothly discharged, and the splash 103 can be greatly reduced.

Further, around the keyhole 101, the bubble of the metal vapor is slowly cooled by the residual heat of the low-intensity laser beam 101, and the metal can be solidified after the metal vapor completely disappears, thereby realizing welding without the keyhole.

Fig. 3(a) is a basic configuration diagram of a laser device according to embodiment 1 in which a concave hollow spherical mirror 30 is added. The only difference from fig. 2(a) is the difference between whether the lenses are convex or concave, and thus common points are omitted. As shown in fig. 3(b), in the case of the concave hollow spherical mirror 30, since the circular laser light 32 passing through the portion 31 of the concave lens which is not the hollow portion of the concave hollow spherical mirror 30 passes through the collimator lens 12 and then enters the condenser lens 13 while slightly enlarging the incident angle, the position of the focal point with respect to the focal point 17 changes. On the focal plane of the condensing point 17, a low-brightness focus 31 of 100 to 1000 μm can be obtained.

[ example 2 ]

Fig. 5(a) is a basic configuration diagram of a laser device according to a second embodiment in which a hollow convex spherical mirror 40 is added between a collimator lens 12 and a condenser lens 13. In the present embodiment, the barrel is a hybrid exit barrel 3, which can be used to condense the exit light from a single-core fiber to achieve keyhole-type and/or heat conduction-type hybrid welding. Inside the hybrid exit barrel 3, a collimator lens 12, a hollow convex spherical mirror 40, and a condenser lens 13 are arranged in this order on the same optical axis 11 as the single-core optical fiber 2.

The laser beam 1 emitted from the single-core optical fiber 2 is collimated by the collimator lens 12, and then the laser beam 42 passing through the hollow portion 41 of the hollow convex spherical mirror 40 is condensed by the condenser lens 13, so that a high-brightness spot 20 capable of keyhole welding is obtained at the condensed spot 17.

On the other hand, as shown in fig. 5(b), since the annular laser light 44 passing through the non-hollow convex lens portion 43 of the hollow convex spherical mirror 40 slightly changes the angle of the incident light with respect to the condenser lens 13, the laser light is condensed at a position 19 slightly before the light-condensed point, is diffused again, and is defocused, whereby a high-low luminance point 44 of 100 to 1000 μm can be obtained on the focal plane of the focal point as in fig. 2 (a).

Fig. 5(b) shows the intensity distribution in which the above-described fine high-luminance dots 43 and large low-luminance dots 44 are superimposed on the object 5 to be welded.

Also, as in fig. 2(a), by changing the size of the hollow portion 41, the intensity values of the high-luminance dots 43 and the large low-luminance dots 44 can be adjusted, and the welding conditions can be changed greatly.

Fig. 6(a) is a basic configuration diagram of a laser device according to embodiment 1 in which a concave hollow spherical mirror 50 is added. The only difference from fig. 5(a) is that only the difference between whether the lens is convex or concave, and thus the common point is omitted.

In the case of the concave hollow spherical mirror 50, since the angle of the incident light is weakly changed with respect to the condensing lens by the ring-shaped laser light 52 passing through the non-hollow portion 51 of the concave hollow spherical mirror 50, the light is defocused at the condensing point 17, and a large low-luminance spot 54 of 100 to 1000 μm can be obtained, and thus the intensity distribution diagram 6(b) in which the fine high-luminance spot 53 and the large low-luminance spot 54 are superimposed on the condensing point 17 can be obtained, which is the same as fig. 2 (b).

[ example 3 ]

Fig. 7 is a basic configuration diagram of a laser device according to a third embodiment, and as shown in fig. 7(a), only the central portion vicinity 60 is a partially convex lens or a partially concave lens, and the periphery is a planar lens 61, between the optical fiber 2 and the collimator lens 12.

In the laser light 14 emitted from the single-core optical fiber 2, since the laser light 62 having passed through the lens portion 60 of the lens 61 passes through the collimator lens 12 and becomes nonparallel, when the light is condensed by the condenser lens 13, a low-luminance spot 64 can be obtained on the focal plane of the condensed spot 17.

On the other hand, since the ring-shaped laser beam 66 having passed through the flat plate portion 65 of the lens 61 passes through the collimator lens 12 and then enters the condenser lens 13 in parallel, the high-luminance spot 63 can be obtained at the converging point 17.

Therefore, as in fig. 2(b), the intensity distribution diagram 7(b) in which the high-luminance dots 63 and the low-luminance dots 64 are fine and the condensed dots 17 are superimposed can be obtained.

[ example 4 ]

Fig. 8(a) is a basic configuration diagram of a laser device according to embodiment 4 in which a hollow conical lens 70 is added between an optical fiber 2 and a collimator lens 12. In the present embodiment, the barrel is a hybrid exit barrel 3, which can be used to condense the exit light from a single-core fiber to achieve keyhole-type and/or heat conduction-type hybrid welding. Inside the hybrid exit barrel 3, a hollow conical lens 70, a collimator lens 12, and a condenser lens 13 are arranged in this order on the same optical axis 11 as the single-core optical fiber 2.

Among the laser light 14 emitted from the single-core optical fiber 2, the laser light 72 passing through the hollow portion 71 of the hollow conical lens 70 is shaped into a collimated light beam by the collimator lens 12 and then condensed by the condenser lens 13, so that a high-luminance focal point 77 satisfying keyhole welding can be obtained at the condensing point 17.

The annular laser light 74 that has passed through the portion 73 of the hollow conical lens 70, without passing through the hollow portion of the hollow conical lens 70, passes through the collimator lens 12, and then is weakly changed in incident angle by the hollow conical lens 70 with respect to the condenser lens 13, and the light flux is focused at a position 75 slightly before the light converging point 17, and is diffused again after being condensed. Therefore, after defocusing, a large low-luminance spot 76 of 100 to 1000 μm can be obtained in the concentric circle shape with respect to the focused spot 17. The low-brightness spot 76 has an effect of raising and preheating the temperature of the workpiece before the keyhole welding, thereby reducing welding spatter. Meanwhile, the keyhole is slowly cooled after being welded, and the effect of preventing air holes and cracks is achieved.

Fig. 8(b) shows an intensity distribution in which the fine high-luminance dots 77 and the large low-luminance dots 76 overlap with the object 5 to be welded.

In addition, since the intensity distribution can be changed by moving the hollow conical lens 70 forward and backward, the welding conditions can be finely optimized.

Further, by changing the size of the hollow portion 71, the intensity values of the high-luminance point 77 and the large low-luminance point 76 can be adjusted, and the welding conditions can be changed greatly.

In the above-described embodiment, the single-core optical fiber 2 can perform the spoon-hole type and heat conduction type hybrid welding of the same high-luminance polymeric spot and low-luminance polymeric spot in a single-mode or multi-mode optical fiber.

In other lasers such as a galvanometer welding head, a wobble welding head, a hand-held welding head, a YAG laser, and an LD laser, keyhole-type and heat conduction-type hybrid welding can also be achieved by placing a hollow spherical mirror in front of the collimating lens.

Fig. 9 shows a comparison of the present embodiment with the prior art. As shown in fig. 9, the present invention can provide more excellent laser devices than the conventional examples.

While the invention has been described with reference to the above embodiments, the scope of the invention is not limited thereto, and the above components may be replaced with similar or equivalent elements known to those skilled in the art without departing from the spirit of the invention.

Claims

1. The utility model provides a laser device, its characterized in that, the device includes single-fiber core optic fibre and is used for carrying out spotlight in order to realize the hybrid welding's of key pass and/or heat-conduction type lens cone to the emergent light that comes from single-fiber core optic fibre, inside and the single-fiber core optic fibre of lens cone have set gradually cavity spherical mirror, collimating lens and condensing lens on same optical axis, cavity spherical mirror sets up in the lens cone and be located between optic fibre export and the collimating lens, cavity spherical mirror is longer than condensing lens's focus distance, and the cavity diameter of cavity spherical mirror sets up in the light beam that the optic fibre jetted out.

2. The utility model provides a laser device, its characterized in that, the device includes single-fiber core optic fibre and is used for carrying out spotlight in order to realize the hybrid welding's of key pass and/or heat-conduction type lens cone to the emergent light that comes from single-fiber core optic fibre, inside collimating lens, cavity spherical mirror and the condensing lens of having set gradually with single-fiber core optic fibre on same optical axis of lens cone, the cavity spherical mirror sets up in the lens cone and be located between collimating lens and the condensing lens, the cavity spherical mirror is longer than condensing lens's focus distance, and the cavity diameter of cavity spherical mirror is in the collimated light beam.

3. The laser device according to claim 1 or 2, wherein the hollow spherical mirror is a hollow convex spherical mirror or a hollow concave spherical mirror.

4. The laser device according to claim 1 or 2, wherein the hollow portion of the hollow spherical mirror is one of a non-hollow plane, a curved surface having a curvature larger than that of the spherical lens, and an aspherical surface.

5. The laser device according to claim 1 or 2, wherein the hollow portion of the hollow spherical mirror is a convex lens or a concave lens, and the periphery of the hollow spherical mirror is a planar lens.

6. A laser device as claimed in claim 1 or 2, wherein the hollow spherical mirror is a hollow conical lens for slightly changing the emission angle of the light beam passing through the conical surface.

7. The laser device according to claim 1 or 2, wherein the hollow spherical mirror is defocused at a condensing point with respect to the condensing lens, and a low-luminance point of 100 to 1000 μm is obtained.

8. The laser device according to claim 7, wherein the laser beam passing through the hollow portion of the hollow spherical mirror among the laser beams emitted from the single-core optical fiber is collimated by the collimator lens and then condensed by the condenser lens, whereby a high-brightness spot satisfying keyhole welding can be obtained at the condensed spot.

9. The laser device according to claim 8, wherein the intensity values of the high-luminance point and the low-luminance point can be adjusted by changing the size of the hollow portion of the hollow spherical mirror.

10. The laser device according to claim 9, wherein the intensity values of the high luminance point and the low luminance point are changed by moving the hollow spherical mirror back and forth.

11. The laser device according to claim 10, wherein the adjustment range of the intensity value of the high-luminance point is 20 to 100%, and the adjustment range of the intensity value of the low-luminance point is 0 to 80%.