Laser welding method, welding structure and electronic equipment

Abstract

The embodiments of the present application relate to the field of welding technology, and provide a laser welding method, a welding structure and an electronic device. The laser welding method includes: providing a first weldment including a first surface and a second weldment including a second surface, a gap between the first weldment and the second weldment, the first surface and the second surface are both located on the side where the same opening of the gap is located, and fixing the filler material on the first surface and the second surface in the form of spanning the gap; and performing laser welding at the gap, so that the filler material melts and fills the gap and fuses with the first weldment and the second weldment to form a weld, wherein the weld connects the first surface and the second surface and welds the first weldment and the second weldment.

Description

Technical Field

[0001] The present application relates to the field of welding technology, and in particular to a laser welding method, a welding structure and an electronic device. Background Art

[0002] In the existing laser welding method, it is difficult to form an effective weld when welding two weldments with a large gap and / or a floating gap. Summary of the invention

[0003] A first aspect of the present application provides a laser welding method. The laser welding method comprises:

[0004] Providing a first weldment including a first surface and a second weldment including a second surface, wherein a gap is provided between the first weldment and the second weldment, the first surface and the second surface are both located on one side of a same opening of the gap, and fixing a caulking material on the first surface and the second surface in a form spanning the gap; and

[0005] Laser welding is performed at the gap, so that the filling material melts and fills the gap and fuses with the first weldment and the second weldment to form a weld, wherein the weld connects the first surface and the second surface and welds the first weldment and the second weldment.

[0006] In the laser welding method provided in the first aspect of the present application, the filler material is in the form of a surface pre-filler. Before laser welding, the filler material covers the gap in the form of spanning the gap and is fixed on the surface of the first weldment and the surface of the second weldment, rather than clamping the filler material in the gap during the laser welding process. In this way, at least in the width direction of the gap, the filler material completely covers the gap. On the one hand, it can avoid the waste of laser energy passing through the gap, improve the utilization rate of laser energy, and also avoid the effect of laser penetration on the mechanism below the gap. On the other hand, it is also conducive to improving the adaptability of precision structure assembly of large gaps and floating gaps. When laser welding is performed on precision structures with large gaps and floating gaps, solder can be effectively filled in the gap to optimize the quality of weld formation and facilitate the formation of an effective weld.

[0007] In some embodiments, fixing the caulking material on the first surface and the second surface includes: completely covering the caulking material with an auxiliary material layer that can transmit the laser and affixing it to the first surface and the second surface. Specifically, the auxiliary material layer can transmit the laser, so as to reduce the loss of laser energy in the subsequent laser welding process. In addition, the auxiliary material layer completely covers the caulking material and affixes it to the first surface and the second surface, which helps to reduce the impact of spatter during laser welding on the welded structural parts and helps to ensure the quality of the weld.

[0008] In some embodiments, fixing the caulking material on the first surface and the second surface further includes: after the auxiliary material layer is attached to the first surface and the second surface, spot welding is performed on the periphery of the gap covered by the caulking material to form a first fixed weld and a second fixed weld, wherein the first fixed weld fixes the caulking material on the first surface, and the second fixed weld fixes the caulking material on the second surface. Specifically, by spot welding the periphery of the gap covered by the caulking material, the shrinkage of the weld spot is utilized to fix the caulking material to the first weldment and the second weldment at the first fixed weld and the second fixed weld, respectively. On the one hand, it is beneficial to fix the caulking material during the laser welding process, and on the other hand, it is beneficial to remove the auxiliary material layer and the caulking material more conveniently along the positions of the first fixed weld and the second fixed weld without affecting the weld after the laser welding process.

[0009] In some embodiments, after forming the weld, the method further includes: removing the auxiliary material layer and the filler material along the first fixed weld and the second fixed weld, and leaving the portion of the filler material between the weld and the first fixed weld on the first surface, and leaving the portion of the filler material between the weld and the second fixed weld on the second surface. Specifically, the excess auxiliary material layer and the filler material can be removed by tearing them off.

[0010] In some embodiments, the auxiliary material layer is attached to the first surface and the second surface by pasting, air suction or magnetic suction. Compared with the method of sandwiching the filler material in the gap, the pasting, air suction or magnetic suction method has high surface mounting efficiency and simple operation, which is conducive to improving the quality of the filler and is more suitable for large-scale production. Moreover, the filler material is attached to the first surface of the first weldment and the second surface of the second weldment, which is not only conducive to achieving good filling of complex three-dimensional curve welds, but also can adapt to floating gaps and large gaps in precision structure assembly.

[0011] In some embodiments, the auxiliary material layer includes an adhesive surface, and fixing the filler material on the first surface and the second surface also includes: adhering the filler material to a local area of ​​the adhesive surface, and adhering the area of ​​the adhesive surface not adhered with the filler material to the first surface and the second surface, but is not limited to this.

[0012] In some embodiments, the auxiliary material layer is transparent, so as to facilitate observation of the alignment of the filler material and the gap through the auxiliary material layer.

[0013] In some embodiments, the auxiliary material layer is flexible to facilitate better pre-fixation of the filler material, so that the filler material fits more closely to the surfaces of the first weldment and the second weldment, thereby facilitating the filler material to fill the complex gaps in the three-dimensional curve well.

[0014] In some embodiments, the gap filling material is a sheet material, a powder material, or a paste material. When the gap filling material is a sheet material, the gap filling material can be first pasted to a local area of ​​the bonding surface, and the area of ​​the bonding surface not pasted with the gap filling material can be pasted to the first surface and the second surface; it can also be first directly set on the first weldment and the second weldment in a manner of crossing the gap, and then one side of the bonding surface of the auxiliary material layer is covered with the gap filling material, and the edge area of ​​the bonding surface of the auxiliary material layer is adhered to the first surface and the second surface, so as to achieve pre-fixation of the gap filling material and improve the flexibility of the process. When the gap filling material is a powder material or a paste material, by first bonding the gap filling material to the auxiliary material layer, and then fixing the stack of the auxiliary material layer and the gap filling material to the first weldment and the second weldment, it is helpful to avoid the problem that when the powdery or paste-like gap filling material is directly set on the first weldment and the second weldment, the corresponding gap is easily leaked in the gap and cannot effectively cross the gap, thereby helping to improve the fixing effect of the gap filling material.

[0015] In some embodiments, a scanning galvanometer laser welding machine is used to perform laser welding at the gap. It should be noted that the known method of laser welding with a follower filler is to perform filler welding by fixing the wire feeding device on the laser head. However, in order to ensure that the welding wire can be accurately fed into the molten pool, the laser spot position and the position of the laser head need to be fixed, that is, the known method of laser welding with a follower filler cannot be used in conjunction with a scanning galvanometer, which greatly limits the efficiency of laser welding. In contrast, the laser welding method of the embodiment of the present application adopts a surface-mounted pre-filling method, and the filling material can be pre-fixed at the welding gap before laser welding. During laser welding, the position of the gap can be welded normally, and there are no additional requirements for the laser welding equipment. When used in conjunction with a scanning galvanometer, the efficiency of laser welding can be improved.

[0016] The second aspect of the present application provides a welded structural part. The welded structural part is obtained by the laser welding method of the first aspect of the present application, and has at least the same advantages as the laser welding method of the first aspect, and the welded structural part has high mechanical strength.

[0017] A third aspect of the present application provides a welding structure, the welding structure comprising:

[0018] A first weldment including a first surface;

[0019] a second weldment including a second surface;

[0020] A weld, welding the first weldment and the second weldment and connecting the first surface and the second surface;

[0021] a first fixing weld located on the first surface;

[0022] a second fixing weld located on the second surface; and

[0023] A caulking material, comprising a first sub-portion located on the first surface and a second sub-portion located on the second surface;

[0024] Among them, the first sub-section is located between the weld and the first fixed weld, and the two opposite ends of the first sub-section are respectively fixed by the weld and the first fixed weld; the second sub-section is located between the weld and the second fixed weld, and the two opposite ends of the second sub-section are respectively fixed by the weld and the second fixed weld.

[0025] In the welded structural part of the third aspect of the present application, the weld is formed by melting the filler material, the material of the first weldment and the material of the second weldment into one and cooling, the first fixed weld is formed by melting the filler material and the material of the first weldment into one and cooling, and the second fixed weld is formed by melting the filler material and the material of the second weldment into one and cooling, so the welded structural part has high mechanical strength.

[0026] A fourth aspect of the present application provides a welding structure, the welding structure comprising:

[0027] a first weldment including a first surface;

[0028] a second weldment including a second surface;

[0029] a caulking material overlapping the first surface and the second surface;

[0030] A weld, welding the first weld and the second weld and connecting the first surface and the second surface, formed by fusing the filler material with the material of the first weld and the material of the second weld;

[0031] a first fixed weld, located on the first surface, spaced apart from the weld, and formed by welding the filler material with the material of the first weldment; and

[0032] The second fixed weld is located on the second surface, spaced apart from the weld, and formed by welding the filler material with the material of the second weldment.

[0033] The welded structural member of the fourth aspect of the present application also has the advantage of high mechanical strength.

[0034] In a fifth aspect, the present application provides an electronic device. The electronic device comprises the welding structure according to the second aspect of the present application, or the welding structure according to the third aspect of the present application, or the welding structure according to the fourth aspect of the present application. The electronic device has at least the same advantages as the above-mentioned welding structures, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of a laser welding method according to an embodiment of the present application.

[0036] Figure 2 This is a side view of fixing the filler material to the first weldment and the second weldment by gluing in one embodiment of the present application.

[0037] Figure 3 This is a top view of fixing the filler material to the first weldment and the second weldment by gluing in one embodiment of the present application.

[0038] Figure 4 This is a schematic diagram of pasting a sealing material to an auxiliary material layer in one embodiment of the present application.

[0039] Figure 5 This is a side view of fixing the filler material to the first weldment and the second weldment by air suction in one embodiment of the present application.

[0040] Fig. 6A This is a side view of fixing the filler material to the first weldment and the second weldment by magnetic attraction in another embodiment of the present application.

[0041] Figure 6B This is a top view of fixing the filler material to the first weldment and the second weldment by magnetic attraction in another embodiment of the present application.

[0042] Figure 6C This is a side view of fixing the filler material to the first weldment and the second weldment by magnetic attraction in another embodiment of the present application.

[0043] Fig.6D This is a side view of fixing the caulking material to the first weldment and the second weldment by magnetic attraction in yet another embodiment of the present application.

[0044] Figure 7 It is a side view of spot welding of the filling material in one embodiment of the present application.

[0045] Figure 8 It is a top view of spot welding of the filling material in one embodiment of the present application.

[0046] Fig. 9 It is a side view of laser welding performed at a gap in one embodiment of the present application.

[0047] Fig.10 This is a top view of laser welding performed at a gap in one embodiment of the present application.

[0048] Fig.11 It is a side view after removing the auxiliary material layer and the filling material along the first fixed weld and the second fixed weld in one embodiment of the present application.

[0049] Fig.12This is a top view after removing the auxiliary material layer and the filling material along the first fixed weld and the second fixed weld in one embodiment of the present application.

[0050] Fig.13 This is a slice diagram of a welded structural component obtained by a laser welding method according to an embodiment of the present application.

[0051] Fig.14 Schematic diagram of different welding joint types.

[0052] Description of main component symbols:

[0053] Welded structural parts 100

[0054] First weldment 10

[0055] First surface 11

[0056] The third surface 13

[0057] Second weldment 20

[0058] Second surface 22

[0059] Fourth surface 24

[0060] Sealing material 30

[0061] First subsection 31

[0062] Second subsection 32

[0063] Auxiliary material layer 40

[0064] Adhesive surface 41

[0065] Fixed weld 50

[0066] First fixing weld 51

[0067] Second fixed weld 52

[0068] Weld 60

[0069] Negative pressure nozzle 70

[0070] Magnet M

[0071] Gap G

[0072] First opening O1

[0073] The second opening O2

[0074] Laser beam L

[0075] First direction X

[0076] Second direction Y

[0077] The third direction Z

[0078] Steps S1 and S2 DETAILED DESCRIPTION

[0079] It should be noted that the "floating gap" in this article refers to the gap value between two weldments to be welded being within a preset range but the gap value is unpredictable.

[0080] In the existing laser welding method, it is difficult to form an effective weld when welding two weldments with large gaps and / or floating gaps. The main reasons for the above problems caused by laser welding in practical applications are as follows: First, the limitations of the structure of the weldment itself cause the welding gap to be large and floating. Specifically, when assembling and welding precise and complex structures (such as the shaft assembly of a folding machine), on the one hand, the large number of parts makes the dimension chain too long, resulting in excessive fitting gaps of the parts; on the other hand, the complex part structure leads to large dimensional tolerances of the parts themselves. In this way, these two aspects are the main factors that lead to large gaps in assembly welding and unpredictable, variable, and non-fixed floating values. Second, the laser welding method has high requirements for the welding gap. Specifically, in the laser welding method, the laser spot diameter is small, the energy is concentrated, and the heat input and melting amount are small. Due to the characteristics of laser welding, when the welding gap is too large, part of the laser energy is wasted through the welding gap, and the transmitted laser energy may also damage other mechanisms under the weld. In addition, part of the laser energy passing through the welding gap will also cause poor bridging of the molten pools on both sides during the welding process, which will affect the weld formation or even prevent the formation of an effective weld. For example, in some cases, the welding gap is about 0.2mm, and direct welding with a laser welding device with a laser spot diameter of about 0.3mm will result in the failure to form an effective weld.

[0081] In this regard, an embodiment of the present application provides a laser welding method. The laser welding method includes providing a first weldment including a first surface and a second weldment including a second surface, wherein a gap is provided between the first weldment and the second weldment, wherein the first surface and the second surface are both located on one side of the same opening of the gap, and a caulking material is fixed on the first surface and the second surface in a form spanning the gap; and laser welding is performed at the gap, so that the caulking material melts and fills the gap and fuses with the first weldment and the second weldment to form a weld, wherein the weld connects the first surface and the second surface and welds the first weldment and the second weldment.

[0082] In the laser welding method provided in the embodiment of the present application, the filler material is in the form of a surface pre-filler. Before laser welding, the filler material covers the gap in the form of spanning the gap and is fixed on the surface of the first weldment and the surface of the second weldment, rather than clamping the filler material in the gap during the laser welding process. In this way, at least in the width direction of the gap, the filler material completely covers the gap. On the one hand, it can avoid the waste of laser energy passing through the gap, improve the utilization rate of laser energy, and also avoid the effect of laser penetration on the mechanism below the gap; on the other hand, it is also conducive to improving the adaptability of precision structure assembly of large gaps and floating gaps. When laser welding is performed on precision structures with large gaps and floating gaps, solder can be effectively filled in the gap to optimize the quality of weld formation and facilitate the formation of an effective weld.

[0083] In addition, an existing laser welding method is to clamp the filling material in the gap during the laser welding process, which requires the gap value to be fixed, and the operation is complicated and has poor mass production performance. However, the method of the embodiment of the present application has simple and efficient surface pre-filling operations, good adaptability to floating gaps within a certain range, and is more suitable for large-scale production.

[0084] Another existing method of laser welding with a follow-up filler is to fix the wire feeding device on the laser head to perform filler welding. This method cannot be used in conjunction with a scanning galvanometer, which greatly limits the efficiency of laser welding. The laser welding method of the embodiment of the present application adopts a surface-mounted pre-filling method. The filling material can be pre-fixed at the welding gap before laser welding. During laser welding, the gap position can be welded normally. There are no additional requirements for the laser welding equipment. When used in conjunction with a scanning galvanometer, the efficiency of laser welding can be improved.

[0085] The embodiment of the present application also provides a welding structure obtained by the above-mentioned laser welding method and an electronic device. The electronic device includes the above-mentioned welding structure. The welding structure is obtained by the above-mentioned laser welding method, and the overall structural stability of the welding structure is improved, which can further improve the service life of the electronic device.

[0086] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0087] like Figure 1 As shown, the laser welding method of an embodiment of the present application includes the following steps S1 and S2. According to different requirements, the order of some steps and / or sub-steps of the laser welding method can be changed, and some steps and / or sub-steps can be omitted or combined.

[0088] Step S1: Provide a first weldment including a first surface and a second weldment including a second surface, wherein a gap is provided between the first weldment and the second weldment, the first surface and the second surface are both located on one side of a same opening of the gap, and a caulking material is fixed to the first surface and the second surface in a form spanning the gap.

[0089] like Figure 2 As shown, the first weldment 10 includes a first surface 11 and a third surface 13 connected to the first surface 11. The second weldment 20 includes a second surface 22 and a fourth surface 24 connected to the second surface 22.

[0090] In some embodiments, step S1 also includes butting the first weld 10 and the second weld 20 on one side to be welded (without using adhesive), so that the third surface 13 and the fourth surface 24 are relatively arranged to form a butt joint, and a gap G between the first weld 10 and the second weld 20 is defined, and there is no adhesive in the gap G, thereby joining the third surface 13 and the fourth surface 24 together.

[0091] In some embodiments, the value of the gap G is large (close to the laser spot) and unpredictable. This is because the first weldment 10 and / or the second weldment 20 are assembled from multiple parts, and because the first weldment 10 and / or the second weldment 20 have dimensional tolerances.

[0092] Please continue reading Figure 2 The gap G includes a first opening O1 and a second opening O2 opposite to each other. The first surface 11 and the second surface 22 are both located on the side where the first opening O1 is located and are both perpendicular to the depth direction of the gap G. The caulking material 30 spans the gap G and directly contacts and closely fits with the first surface 11 and the second surface 22.

[0093] For the convenience of description, the direction from the third surface 13 of the first weldment 10 to the fourth surface 24 of the second weldment 20 (also referred to as the width direction of the gap G) is defined as the first direction X, the length direction of the gap G is defined as the second direction Y, and the depth direction of the gap G is defined as the third direction Z. The first direction X, the second direction Y, and the third direction Z constitute a rectangular coordinate system.

[0094] Please refer to Figure 2 and Figure 3 The gap filling material 30 is fixed on the first surface 11 and the second surface 22 through the auxiliary material layer 40. The auxiliary material layer 40 completely covers the gap filling material 30 and extends beyond the edge area of ​​the gap filling material 30 and is adhered to the first surface 11 and the second surface 22.

[0095] Figure 2 and Figure 3In the illustrated embodiment, the first weldment 10 and the second weldment 20 are rectangular parallelepiped, the gap G is in the shape of a long strip, and the outer contours of the auxiliary material layer 40 and the filler material 30 are rectangular. In other embodiments, the shapes of the first weldment 10, the second weldment 20, the gap G, the auxiliary material layer 40 and the filler material 30 are not limited. For example, the first weldment 10, the second weldment 20, and the gap G can be other irregular three-dimensional structures, such as the third surface 13 and the fourth surface 24 can also be three-dimensional curved surfaces, so that the gap G has a three-dimensional complex structure. Alternatively, the first surface 11 and the second surface 22 have undulating changes along the third direction Z.

[0096] Please refer to Figure 2 and Figure 4 The auxiliary material layer 40 includes a sticky adhesive surface 41. Fixing the sealant 30 to the first surface 11 and the second surface 22 also includes: sticking the sealant 30 to a local area of ​​the adhesive surface 41, and then sticking the area of ​​the adhesive surface 41 that is not stuck with the sealant 30 to the first surface 11 and the second surface 22.

[0097] Specifically, the materials of the first weldment 10 and the second weldment 20 can be selected from at least one of titanium metal, titanium alloy, aluminum alloy, magnesium alloy, carbon fiber, carbon steel, stainless steel, cobalt alloy, and nickel alloy. The filler material 30 can be the same material as the first weldment 10 and / or the second weldment 20, or different materials but with the same melting point, so that during subsequent laser welding, the filler material 30 has good compatibility with the materials of the first weldment 10 and / or the second weldment 20, which is conducive to forming an effective weld.

[0098] The auxiliary material layer 40 has a certain light transmittance to allow the laser to pass through, so as to reduce the loss of laser energy in the subsequent laser welding process.

[0099] The gap filling material 30 is a sheet material (such as a metal foil), but is not limited thereto. When the gap filling material 30 is a sheet material, the gap filling material 30 can also be directly disposed on the first weldment 10 and the second weldment 20 in a manner of spanning the gap G, and then one side of the bonding surface 41 of the auxiliary material layer 40 is covered with the gap filling material 30, and the edge area of ​​the bonding surface 41 of the auxiliary material layer 40 is attached to the first surface 11 and the second surface 22, so as to achieve pre-fixation of the gap filling material 30 and improve the flexibility of the process.

[0100] The gap filling material 30 may also be a powder material or a paste material. When the gap filling material 30 is a powder material or a paste material, by first bonding the gap filling material 30 to the auxiliary material layer 40, and then fixing the stack of the auxiliary material layer 40 and the gap filling material 30 to the first weldment 10 and the second weldment 20, it is helpful to avoid the problem that when the powder or paste gap filling material 30 is directly set on the first weldment 10 and the second weldment 20, the corresponding gap G is easily leaked in the gap G and cannot effectively cross the gap G, thereby helping to improve the fixing effect of the gap filling material 30.

[0101] In some embodiments, the auxiliary material layer 40 is transparent, so that the alignment of the filler material and the gap G can be observed through the auxiliary material layer 40 .

[0102] In some embodiments, the auxiliary material layer 40 is a flexible, deformable material, so as to better pre-fix the filling material 30, so that the filling material 30 can fit more closely to the surface of the first weldment 10 and the second weldment 20, thereby facilitating the filling material 30 to fill the complex gap G of the three-dimensional curve well.

[0103] In some embodiments, the auxiliary material layer 40 is a transparent tape or release paper that can transmit laser light, but is not limited thereto.

[0104] Figures 2 to 4 In the illustrated embodiment, the auxiliary material layer 40 is adhered and fixed to the first surface 11 and the second surface 22 by gluing.

[0105] In other embodiments, the auxiliary material layer 40 can be attached and fixed to the first surface 11 and the second surface 22 by using air suction and using air pressure difference instead of the viscosity requirement of the auxiliary material layer 40. In the air suction method, the auxiliary material layer 40 mainly plays a role in enhancing the negative pressure adsorption. When the sealing material 30 is a sheet material, the auxiliary material layer 40 can be used or not; when the sealing material 30 is a powder material or a paste material, it needs to be fixed with the auxiliary material layer 40, but the viscosity of the auxiliary material layer 40 is not limited.

[0106] Specifically, Figure 5 As shown, the gap filling material 30 is one of a sheet material, a powder material or a paste material, and the auxiliary material layer 40 is a film layer that allows laser light to pass through, and the auxiliary material layer 40 may not be sticky. By arranging a negative pressure air nozzle 70 on the side of the gap G away from the gap filling material 30 along the third direction Z, a low pressure area is formed on the side of the gap G away from the gap filling material 30, so that a pressure difference is formed on the opposite sides of the auxiliary material layer 40, so that the gap filling material 30 is attached to the first surface 11 and the second surface 22 and pre-fixed under the action of the auxiliary material layer 40 by air suction.

[0107] In other embodiments, the auxiliary material layer 40 can be attached and fixed to the first surface 11 and the second surface 22 by magnetic attraction. In the magnetic attraction method, the auxiliary material layer 40 mainly serves to increase the magnetic attraction area. When the gap filling material 30 is a sheet material, the auxiliary material layer 40 can be used or not, depending on the size of the gap filling material 30; when the gap filling material 30 is a powder material or a paste material, the auxiliary material layer 40 is required, but the viscosity of the auxiliary material layer 40 is not limited.

[0108] Specifically, Fig. 6A and Figure 6B As shown, the first welding piece 10 and the second welding piece 20 are both made of magnetic materials, and the auxiliary material layer 40 is a film layer that allows laser light to pass through, but is not sticky. The gap filling material 30 is a sheet material, and the gap filling material 30 can be directly overlapped on the first surface 11 and the second surface 22 in a manner of crossing the gap G, and then the auxiliary material layer 40 covers the gap filling material 30, and then magnets M are respectively arranged on the side of the auxiliary material layer 40 away from the first welding piece 10 and the side of the auxiliary material layer 40 away from the second welding piece 20 along the third direction Z, and the auxiliary material layer 40 is attached to the first surface 11 and the second surface 22 through the magnetic attraction between the magnet M and the first welding piece 10 and between the magnet M and the second welding piece 20, so that the gap filling material 30 is attached and pre-fixed on the first surface 11 and the second surface 22.

[0109] In other embodiments, the gap filling material 30 is one of a sheet material, a powder material or a paste material, and the auxiliary material layer 40 is a film layer that allows laser light to pass through, and the auxiliary material layer 40 is sticky. The gap filling material 30 can be firstly pasted to a local area of ​​the bonding surface 41, and then the area of ​​the bonding surface 41 not pasted with the gap filling material 30 is pasted to the first surface 11 and the second surface 22, and magnets M are respectively arranged on the side of the auxiliary material layer 40 away from the first weldment 10 and the side of the auxiliary material layer 40 away from the second weldment 20 along the third direction Z, and the gap filling material 30 is adhered and pre-fixed on the first surface 11 and the second surface 22 through the magnetic attraction between the magnet M and the first weldment 10 and between the magnet M and the second weldment 20.

[0110] In some other embodiments, Figure 6C As shown, magnets can be placed on the surface of the first welding piece 10 and the second welding piece 20, and a magnet with another magnetic pole can be placed on the surface of the auxiliary material layer 40, so that the two magnets on the upper and lower sides of the same welding piece attract each other to achieve pre-fixation of the caulking material 30. Alternatively, as Fig.6D As shown, the filling material 30 is a sheet material, and the auxiliary material layer 40 can be omitted. By placing magnets on the surfaces of the first weldment 10 and the second weldment 20, and placing a magnet with another magnetic pole on the surface of the filling material 30, the two magnets on the upper and lower sides of the same weldment are attracted to each other to achieve pre-fixation of the filling material 30.

[0111] Since the filling material 30 can be fixed on the surfaces of the first weldment 10 and the second weldment 20 by covering the gap G through the auxiliary material layer 40 by means of adhesion, air suction, magnetic suction, etc., compared with the method of clamping the filling material in the gap: first, the surface mounting efficiency is high and the operation is simple, which is conducive to improving the quality of the filler and is more suitable for large-scale production; second, the filling material 30 is attached to the first surface 11 of the first weldment 10 and the second surface 22 of the second weldment 20, which can realize flexible filler, which is conducive to achieving good filling of complex three-dimensional curved welds; third, it can also adapt to floating gaps and large gaps in precision structure assembly.

[0112] In some embodiments, step S1 further includes spot welding the periphery of the gap covered by the filler material after laminating the auxiliary material layer on the first surface and the second surface to form a first fixed weld and a second fixed weld. The first fixed weld fixes the filler material on the first surface, and the second fixed weld fixes the filler material on the second surface.

[0113] like Figure 7 and Figure 8 As shown, the caulking material 30 is spot welded around the gap G to form a fixed weld 50, which includes a first fixed weld 51 and a second fixed weld 52. The first fixed weld 51 and the second fixed weld 52 are respectively located on opposite sides of the gap G in the width direction, and both extend along the length of the gap G (i.e., the second direction Y). By shrinking the welding spot, the caulking material 30 is fixed to the first weldment 10 and the second weldment 20 at the first fixed weld 51 and the second fixed weld 52, respectively. It should be noted that Figure 8 The first fixed weld 51 and the second fixed weld 52 shown in the figure are both linear, but not limited thereto. In some embodiments, the first fixed weld 51 and the second fixed weld 52 can be a plurality of point-shaped welds arranged at intervals.

[0114] Step S2: laser welding is performed at the gap to melt the filling material into the gap and fuse with the first weldment and the second weldment to form a weld, wherein the weld connects the first surface and the second surface and welds the first weldment and the second weldment.

[0115] like Fig. 9 and Fig.10As shown, at the gap G between the first weldment 10 and the second weldment 20, the power of the output laser beam L can be controlled so that the gap filling material 30 near the gap G absorbs the laser energy and melts and fills the gap G, and the part of the first weldment 10 adjacent to the gap G and the part of the second weldment 20 adjacent to the gap G are melted, and then the melted gap filling material 30 merges with the melted part of the first weldment 10 and the melted part of the second weldment 20 to form a mixed molten pool, and after cooling, a weld 60 is formed that connects the first surface 11 and the second surface 22 and welds the first weldment 10 and the second weldment 20. The weld 60 closes an opening of the gap G (i.e., the first opening O1 mentioned above).

[0116] Specifically, the spatial and temporal density of laser energy is extremely large, and its special mechanism of interaction with materials enables laser welding to achieve extremely narrow weld width, large penetration depth and small heat-affected zone. Therefore, the quality of laser welding is high. In addition, due to the small spot diameter of laser welding, the heat input and melting amount are small. When the weld gap is large, in conventional laser welding methods, most of the laser energy is wasted through the gap, and only a small part of the energy is absorbed by the parent materials on both sides to form a smaller molten pool, which makes it more difficult to bridge the molten pool metal, resulting in the weld forming being affected or even unable to form a weld. In the laser welding method of the embodiment of the present application, the filler material 30 is fixed across the gap G and the first weldment 10 and the second weldment 20, or in other words, in the width direction of the gap G, the filler material 30 completely covers the gap G, so that the energy of the laser beam L can be avoided from being wasted through the gap G, the utilization rate of the laser energy is improved, and the effect of the laser on the mechanism below the gap is avoided. At the same time, the gap is filled with solder to optimize the weld forming quality.

[0117] In addition, since the auxiliary material layer 40 completely covers the filling material 30, it is helpful to reduce the impact of spatter during laser welding on the welded structural parts, and to ensure the quality of the weld.

[0118] In some embodiments, a scanning galvanometer laser welding machine (not shown) is used to perform laser welding at the gap G. Specifically, the scanning galvanometer laser welding machine includes, for example, a laser, a controller, an X-axis galvanometer motor, an X-axis reflector, a Y-axis galvanometer motor, and a Y-axis reflector. The laser beam is incident on the X-axis reflector and the Y-axis reflector in a pulsed or continuous manner. The X-axis reflector and the Y-axis reflector can scan along the X-axis and the Y-axis, respectively. The controller can control the reflection angles of the X-axis reflector and the Y-axis reflector, thereby realizing the deflection movement of the laser beam, and then realizing the alignment welding. In the embodiment of the present application, a scanning galvanometer laser welding machine is used to perform laser welding at the gap G, and all welded gaps G in a certain area can be asynchronously and simultaneously welded, greatly improving the welding efficiency.

[0119] In some embodiments, after forming the weld 60, the entire auxiliary material layer 40 is removed, and a portion of the filler material 30 is removed, so that the filler material 30 outside the first fixed weld 51 and the second fixed weld 52 is removed, and the filler material 30 between the first fixed weld 51 and the second fixed weld 52 is retained, that is, the portion of the filler material 30 located between the weld 60 and the first fixed weld 51 is retained on the first surface 11, and the portion of the filler material 30 located between the weld 60 and the second fixed weld 52 is retained on the second surface 22.

[0120] Specifically, the excess auxiliary material layer 40 and the filler material 30 can be removed by tearing. After spot welding, the filler material 30 between the weld 60 and the first fixed weld 51 is fixed by the weld 60 and the first fixed weld 51, and is therefore retained on the first surface 11. The filler material 30 between the weld 60 and the second fixed weld 52 is fixed by the weld 60 and the second fixed weld 52, and is therefore retained on the second surface 22. Moreover, due to the provision of the first fixed weld 51 and the second fixed weld 52, the process of tearing off the excess auxiliary material layer 40 and the filler material 30 is more convenient, and will not affect the weld 60.

[0121] like Fig.11 and Fig.12 As shown, after the auxiliary material layer 40 and the filling material 30 are removed, a portion of the filling material 30 and a specific weld structure remain on the first surface 11 and the second surface 22 of the welded structural component 100 .

[0122] Specifically, the welded structural member 100 includes a first weld 10, a second weld 20, a filler material 30, a first fixed weld 51, a second fixed weld 52, and a weld 60. The first fixed weld 51 is located on the first surface 11, and the second fixed weld 52 is located on the second surface 22. The weld 60 is formed by melting and cooling a part of the filler material 30, a part of the material of the first weld 10, and a part of the material of the second weld 20. The first fixed weld 51 is formed by melting and cooling a part of the filler material 30 and a part of the material of the first weld 10. The second fixed weld 52 is formed by melting and cooling a part of the filler material 30 and a part of the material of the second weld 20. In other words, the weld 60 is formed by the fusion of the filler material 30 with the material of the first weld 10 and the material of the second weld 20; the first fixed weld 51 is formed by the fusion of the filler material 30 with the material of the first weld 10; and the second fixed weld 52 is formed by the fusion of the filler material 30 with the material of the second weld 20.

[0123] The filler material 30 between the weld 60 and the first fixed weld 51 is in direct contact with and tightly fits the first surface 11, and defines a first subsection 31 of the filler material 30. The filler material 30 between the weld 60 and the second fixed weld 52 is in direct contact with and tightly fits the second surface 22, and defines a second subsection 32 of the filler material 30. Along the first direction X, the two opposite ends of the first subsection 31 are respectively fixed by the weld 60 and the first fixed weld 51, so that the welded structure 100 has a certain load-bearing capacity. Along the first direction X, the two opposite ends of the second subsection 32 are respectively fixed by the weld 60 and the second fixed weld 52, so that the welded structure 100 has a certain load-bearing capacity. The weld 60 closes an opening of the gap G, and the second opening O2 of the gap G is exposed. In other embodiments, the weld 60 can completely close the first opening O1 and the second opening O2 relative to the gap G. It should be noted that, Fig.11 The depressions at the curves corresponding to the first fixed weld 51 and the second fixed weld 52 are only used to indicate that there are welds at these positions; they do not mean that depressions are formed corresponding to the first fixed weld 51 and the second fixed weld 52. Fig.13 As shown, the first fixed weld 51 and the second fixed weld 52 are protruding relative to the surface of the first weld 10 and the second weld 20 due to the increase of material.

[0124] In summary, the laser welding method of the embodiment of the present application is particularly helpful in solving the problem that floating gaps and / or large gaps affect weld formation in dense laser welding scenarios. It should be noted that the known method of laser welding with a follower filler performs filler welding by fixing the wire feeding device on the laser head. However, in order to ensure that the welding wire can be accurately fed into the molten pool, the laser spot position and the position of the laser head need to be fixed, that is, the known method of laser welding with a follower filler cannot be used in conjunction with a scanning galvanometer, which greatly limits the efficiency of laser welding. In contrast, the laser welding method of the embodiment of the present application adopts a surface-mounted pre-filling method, and the filling material can be pre-fixed at the welding gap before laser welding. During laser welding, the position of the gap can be welded normally, and there are no additional requirements for the laser welding equipment. When used in conjunction with a scanning galvanometer, the efficiency of laser welding can be improved.

[0125] In addition, a known method of laser welding with pre-fillers is to fix a certain shape of filler between two weldments inside the welding gap, which is effective for gaps of fixed values. In the assembly welding of precise and complex structures, the welding gap comes from the accumulation of dimensional tolerances of parts and components, and the welding gap value is floating, and the size of the filler to be filled cannot be predicted. Moreover, for precise and complex structures, the operation of pre-fixing fillers at the ends of weldments is too complicated and has poor mass production performance. In contrast, the surface mount pre-filler method of the embodiment of the present application has better adaptability to floating gaps within a certain range, and the mounting auxiliary material method is more suitable for large-scale mass production.

[0126] In addition, it should be noted that Fig.14 As shown, welding joint types include Fig.14 The butt joint shown in Figure (a) Fig.14 The lap joint shown in Figure (b) Fig.14 The T-shaped (cross) connector shown in Figure (c) Fig.14 The corner joints shown in Figures (d) and (e) and Fig.14 The laser welding method of the embodiment of the present application is applicable to butt joints among the welding joint types, and does not limit the structure outside the weld area of ​​the first weldment and the second weldment. The laser welding method of the embodiment of the present application can improve the joint strength of the butt joint weldment.

[0127] The embodiment of the present application also provides an electronic device (not shown). The electronic device is a foldable electronic device, for example, a foldable mobile phone, a foldable wearable device, etc. The electronic device includes a first shell, a second shell, a screen and a hinge assembly, and the screen covers the first shell and the second shell. The first shell and the second shell realize the opening or closing of the screen through the hinge assembly. The hinge assembly includes a welding structure obtained by the above-mentioned laser welding method. The first weldment and the second weldment are, for example, two brackets in the hinge assembly. The welding structure is obtained by the above-mentioned laser welding method. The mechanical strength of the welding structure is high, which can further improve the service life of the electronic device. It can be understood that the electronic device is not limited to an electronic device with a hinge assembly, and it can also be other electronic devices with welding structures.

[0128] The above implementation modes are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the above preferred implementation modes, a person skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A laser welding method, characterized in that: include: Providing a first weldment including a first surface and a second weldment including a second surface, wherein a gap is provided between the first weldment and the second weldment, the first surface and the second surface are both located on one side of a same opening of the gap, and fixing a caulking material on the first surface and the second surface in a form of spanning the gap; as well as Performing laser welding at the gap, so that the filling material melts, fills the gap, and fuses with the first weldment and the second weldment to form a weld, wherein the weld connects the first surface and the second surface and welds the first weldment and the second weldment; Among them, fixing the filling material on the first surface and the second surface includes: completely covering the filling material with an auxiliary material layer that can transmit laser and adhering it to the first surface and the second surface, and spot welding the periphery of the filling material covering the gap to form a first fixed weld and a second fixed weld, wherein the first fixed weld fixes the filling material on the first surface, and the second fixed weld fixes the filling material on the second surface.

2. The laser welding method according to claim 1, characterized in that: After forming the weld, the laser welding method further includes: removing the auxiliary material layer and the filling material along the first fixed weld and the second fixed weld, and allowing the portion of the filling material located between the weld and the first fixed weld to remain on the first surface, and allowing the portion of the filling material located between the weld and the second fixed weld to remain on the second surface.

3. The laser welding method according to claim 1, characterized in that: The auxiliary material layer is adhered to the first surface and the second surface by bonding, air suction or magnetic suction.

4. The laser welding method according to claim 1, characterized in that: The auxiliary material layer includes an adhesive surface, and fixing the filler material on the first surface and the second surface also includes: sticking the filler material to a local area of ​​the adhesive surface, and sticking the area of ​​the adhesive surface not stuck with the filler material to the first surface and the second surface.

5. The laser welding method according to claim 1, characterized in that: The auxiliary material layer is transparent.

6. The laser welding method according to claim 1, characterized in that: The auxiliary material layer is flexible.

7. The laser welding method according to any one of claims 1 to 6, characterized in that: The filling material is a sheet material, a powder material, or a paste material.

8. The laser welding method according to claim 7, characterized in that: Laser welding is performed at the gap using a scanning galvanometer laser welding machine.

9. A welded structural part, characterized in that: The method is obtained by the laser welding method according to any one of claims 1 to 8.

10. An electronic device, characterized in that: Comprising the welded structural member according to claim 9.

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