A structure and method for realizing laser brazing of micro joints by conveying soft and fine welding wires

Abstract

The present application discloses a structure and method for realizing laser brazing of micro joints by conveying soft and fine welding wires, which relates to the field of laser brazing. The wire feeding structure includes a machine body, which is provided with a laser for melting the welding wire and can move horizontally, and is provided with a wire winding roller; an elastic wire feeding nozzle, which is connected to the machine body and is driven by the machine body to move vertically, and includes: a housing, which is connected to the machine body; a ceramic tube, one end of which is slidably connected to the housing along a straight line direction, and the other end is provided with an eccentric hole for positioning the end of the welding wire and a V-shaped groove for positioning the joint to be welded. The welding wire passes through the housing, the ceramic tube, and the eccentric hole in sequence from the wire winding roller; a connecting component, which is used to drive the ceramic tube to move in the direction of extending out of the housing. The problems of irregular ends of the welding wire and easy wire clogging during the wire feeding process of the welding wire are solved when laser brazing of this structure is carried out by conveying soft and fine welding wires, so as to stably and continuously realize laser brazing of this structure.

Description

Technical Field

[0001] The invention relates to a laser brazing method based on an eccentric hole ceramic tube elastic wire feeding nozzle conveying fine soft welding wire, and is particularly suitable for laser brazing of joints formed by tiny intersecting holes and shafts. Background Art

[0002] When laser brazing is used to weld structural parts, the wire end is typically exposed for a certain length and fed to the joint at a certain angle. The laser is then aimed at the joint to heat it, and the wire feed mechanism continuously feeds a length of wire. The wire is continuously melted by the laser and penetrates the narrow joint gap, thus forming the weld joint. However, for small joints (≤Φ2mm), continuous and stable welding is difficult when using this method to feed thin and soft wire (0.3mm to 0.5mm) at a certain angle for laser welding. The main reasons include:

[0003] (1) Wire blocking occurs when the wire feeding speed, wire rewinding speed, and welding temperature are not matched. This includes wire blocking caused by the welding temperature not reaching the melting point of the solder during wire feeding, which results in the wire end being blocked by the welded joint. This also includes wire blocking caused by the welding temperature not reaching the melting point of the solder during wire rewinding, which results in the wire sticking to the weld joint.

[0004] (2) The welding process easily forms irregular wire ends, resulting in inability to weld continuously. To prevent the wire from being welded to the metal wire feed nozzle during wire rewinding, the wire feed nozzle must be spaced a certain distance from the welding point, and the wire is conveyed bare along this path. On the one hand, the exposed thin and soft wire is easily softened by heat in the vicinity of the laser spot, causing the wire end to bend and unable to be accurately conveyed to the welding point. On the other hand, because the exposed section of the wire is not constrained by the wire feed nozzle, the end position is easily deviated, which also makes it difficult to align the welding point during the conveying process.

[0005] In the article "A quantitatively cut tin wire clamp melting laser soldering system and soldering method thereof" (CN111299738B), the tin wire is quantitatively cut and transported to the melting chamber. After the tin wire is melted, it is blown to the opening of the welding chuck under the action of air pressure. The tin liquid flows out of the opening and penetrates into the soldering point below the opening of the welding chuck. Subsequently, the chuck is lifted to separate the tin liquid from the chuck, and the chuck is opened. The laser is used to pass through the opening of the chuck to heat the tin material on the pad again and form the final soldering point. This method can solve the problem of wire clogging during laser brazing wire feeding, but it also has the problems of complex structure and inconvenient maintenance. In addition, in addition to tin, this method is also difficult to be compatible with solders with higher melting points. Summary of the Invention

[0006] The technical problem solved by the present invention is: to overcome the shortcomings of the existing technology and provide a laser brazing method based on an eccentric hole ceramic tube elastic wire feeding nozzle to realize the welding of tiny intersecting holes and shafts, so as to solve the problems of irregular wire ends and easy wire blockage during the wire feeding process when conveying fine and soft welding wire for laser brazing of the structure, thereby realizing stable and continuous laser brazing of the structure.

[0007] The technical solution of the present invention is:

[0008] A structure for conveying thin and soft welding wire to achieve laser brazing of micro joints, comprising:

[0009] The machine body is equipped with a laser for melting the welding wire, can be moved horizontally, and is equipped with a wire winding roller;

[0010] The elastic wire feeding nozzle is connected to the machine body and is driven by the machine body to move vertically, including:

[0011] a housing connected to the body;

[0012] The ceramic tube is connected to the shell in a linear sliding manner at one end, and the other end is provided with an eccentric hole for positioning the end of the welding wire and a V-shaped groove for positioning the welding head. The welding wire passes through the shell, the ceramic tube, and the eccentric hole in sequence from the wire winding roller;

[0013] The connecting assembly is used to drive the ceramic tube to move in a direction extending out of the shell.

[0014] The eccentric hole is located right above the V-shaped groove.

[0015] The joint to be welded is a shaft structure with intersecting holes and a cylindrical pin installed in the intersecting holes; the shaft structure is arranged horizontally, and the opening side of the V-shaped groove is in contact with the arc circumference of the shaft structure for positioning.

[0016] The connecting assembly includes a guide sleeve, a linear bearing and an elastic member, the guide sleeve is fixedly connected to the ceramic tube, the linear bearing is fixedly connected to the housing, the guide sleeve is slidably connected to the inner side of the linear bearing, and the elastic member is connected to the housing and between the end of the guide sleeve located in the housing;

[0017] A positioning portion is provided at the end of the guide sleeve located in the housing. The outer diameter of the positioning portion is larger than the inner diameter of the linear bearing. The positioning portion is located on a side of the linear bearing away from the eccentric hole.

[0018] The end of the shell away from the ceramic tube is connected with a connecting rod, and the elastic member is connected to the connecting rod.

[0019] The connecting rod is connected to the machine body through a displacement adjustment rod; the displacement adjustment rod comprises an angle adjustment rod and a height adjustment rod which are hinged to each other, the angle adjustment rod is connected to the connecting rod, and the height adjustment rod is connected to the machine body.

[0020] The guide sleeve is fixedly connected with a pin rod, and the shell is provided with a U-shaped groove extending along the axis direction of the shell, and the pin is clamped in the U-shaped groove.

[0021] A wire feeding hose is provided in the connecting rod, and the wire feeding hose extends from the connecting rod to the joint between the guide sleeve and the eccentric hole of the ceramic tube;

[0022] The diameter of the wire feeding hose is 0.1-0.3 mm larger than the diameter of the welding wire, and the diameter of the eccentric hole of the ceramic tube is 0.1-0.2 mm larger than the diameter of the welding wire.

[0023] A method for conveying fine soft welding wire to realize laser brazing of micro joints, using the above-mentioned structure for conveying fine soft welding wire to realize laser brazing of micro joints, comprising:

[0024] Place the elastic wire feed nozzle at the same height as the joint to be welded, then move the elastic wire feed nozzle horizontally until the V-shaped groove abuts against the joint to be welded, while the laser irradiates the joint to be welded on the upper surface of the joint to be welded;

[0025] When the length of the welding wire fed to the surface of the head to be welded is sufficient, the machine body is moved horizontally in a direction away from the head to be welded.

[0026] The wire feeding inclination angle of the welding wire is 0-5°.

[0027] By designing an elastically retractable wire feeder with an eccentric hole and V-shaped positioning grooves in a ceramic tube, a thin, soft welding wire is horizontally fed above the joint to be welded, achieving close contact between the wire and the joint. Laser irradiation from above melts the wire, allowing the liquid solder to penetrate the interior of the joint, forming the joint to be welded. Furthermore, during the laser heating process, the wire is separated from the weld joint by moving the entire wire feeder, rather than simply retracting the wire. This prevents the irregularly shaped end of the melting wire from getting stuck in the ceramic tube during wire retraction, thus achieving stable and continuous laser brazing.

[0028] In summary, this application has at least the following beneficial technical effects:

[0029] (1) Using an eccentric hole ceramic tube with elastic expansion and contraction and a V-shaped positioning groove as the wire feeding nozzle can ensure that the front end of the thin and soft welding wire (diameter 0.3mm to 0.5mm) is accurately delivered to the top of the joint and in close contact with the joint. This is due to the following reasons: On the one hand, the ceramic tube is positioned with the outer surface of the intersecting hole / axis joint through the V-shaped positioning groove, and the welding wire passes through the eccentric hole of the ceramic tube and can be delivered just above the joint. On the other hand, the exposed welding wire in the vicinity of the laser action will be softened by heat, resulting in the inability to accurately deliver it to the top of the joint. By adding a ceramic tube, the laser can be shielded to prevent the welding wire in the ceramic tube from softening; moreover, the ceramic tube can withstand high temperatures and will not weld with the solder and the joint, facilitating stable and continuous welding.

[0030] (2) The wire feeding angle used is 0°, that is, the thin and soft welding wire is horizontally fed to the top of the head to be welded. This can avoid the problem of the front end of the welding wire pressing against the head to be welded and causing wire blockage when the wire feeding speed does not match the melting of the welding wire. In addition, the welding wire should extend out of the eccentric orifice of the ceramic tube (1mm~2mm) to ensure that the welding wire and the head to be welded are in close contact after the ceramic tube and the head to be welded are positioned. In addition, instead of using only the welding wire retraction method to separate the welding wire from the weld pool, the welding wire and the head to be welded are separated by moving the wire feeding device as a whole during the laser heating process. This can avoid the problem of the irregular shape of the end of the welding wire that may be formed after melting and getting stuck in the inner hole of the ceramic tube during the welding wire retraction process, causing wire blockage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a structural diagram of the components of the laser brazing device in the embodiment of the present application;

[0032] Figure 2 This is a structural diagram of the ceramic tube elastic wire feeding device in an embodiment of the present application;

[0033] Figure 3 This is a diagram of the internal structure of the ceramic tube elastic wire feeding device in an embodiment of the present application.

[0034] Explanation of reference numerals: 1. elastic wire feeding nozzle; 2. position adjustment rod; 4. wire feeding gear; 5. wire winding roller; 6. laser;

[0035] 11. Ceramic tube; 12. Guide sleeve; 13. Housing; 14. Linear bearing; 15. Spring; 16. Connecting rod; 17. Head to be welded; 19. Pin; 21. Height adjustment rod; 22. Angle adjustment rod; 23. Fixing screw; 31. Wire feed hose; 32. Welding wire. DETAILED DESCRIPTION

[0036] The present application is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0037] The embodiments of the present application mainly achieve stable and continuous brazing of fine and soft welding wires through the design of an eccentric hole ceramic tube elastic wire feeding nozzle, the selection of a wire feeding angle for fine and soft welding wires, and the separation of the front end of the welding wire and the weld pool.

[0038] The present application discloses a structure and method for conveying thin and soft welding wire to realize laser brazing of micro joints, such as Figure 1As shown in the figure, a structure for realizing laser brazing of micro joints by conveying soft and fine welding wire 32 includes a machine body and an elastic wire feeding nozzle 1. The machine body can move horizontally in the direction of approaching and departing from the joint to be welded 17. The machine body is provided with a laser 6 for melting the welding wire 32 and a wire winding roller 5. The elastic wire feeding nozzle 1 is connected to the machine body and is driven by the machine body to move vertically. By rotating the wire feeding gear 4, the soft and fine welding wire 32 wound on the wire winding roller 5 is fed into the elastic wire feeding nozzle 1. The elastic wire feeding nozzle 1 conveys the front end of the welding wire 32 above the joint to be welded 17 of the joint to be welded 17. At this time, the laser 6 emits laser to melt the welding wire 32, and the liquid solder penetrates into the joint to be welded 17 to realize joint welding.

[0039] As Figure 2 shown in the figure, the elastic wire feeding nozzle 1 includes a housing 13, a connecting rod 16, a ceramic tube 11, and a connecting component. The connecting rod 16 is connected to one end of the housing 13, the ceramic tube 11 is connected to the other end of the housing 13, and the connecting component is connected between the housing 13 and the ceramic tube 11 for driving the ceramic tube 11 to move in the direction of extending out of the housing 13. The material of the ceramic tube 11 is white fused alumina. The ceramic tube 11 is provided with an eccentric hole for positioning the end of the welding wire 32 and a V-shaped groove for positioning the joint to be welded 17. The eccentric hole is located directly above the positioning groove. The welding wire 32 passes through the housing 13, the ceramic tube 11, and the eccentric hole in sequence from the wire winding roller 5. The joint to be welded 17 is a shaft structure with an intersecting hole and a cylindrical pin installed in the intersecting hole. The shaft structure is horizontally arranged, and the opening side of the V-shaped groove is in circumferential contact positioning with the arc of the shaft structure. The connecting rod 16 is connected to the machine body through a displacement adjusting rod 2. The displacement adjusting rod 2 includes an angle adjusting rod 22 and a height adjusting rod 21 that are hinged to each other. The angle adjusting rod 22 is connected to the connecting rod 16, and the height adjusting rod 21 is connected to the machine body. A fixing screw 23 fixes the connecting rod 16 and the angle adjusting rod 22, and the height adjusting rod 21 and the angle adjusting rod 22 can realize the adjustment of the wire feeding angle and height of the elastic wire feeding nozzle 1.

[0040] As Figure 3 shown in the figure, the connecting component includes a guide sleeve 12, a linear bearing 14, and an elastic member. In this embodiment, the elastic member is a spring 15. The guide sleeve 12 is fixedly connected to the ceramic tube 11, the linear bearing 14 is fixedly connected inside the housing 13, the guide sleeve 12 is slidably connected to the inner side of the linear bearing 14, and the end of the guide sleeve 12 located inside the housing 13 is provided with a positioning portion. The outer diameter of the positioning portion is larger than the inner diameter of the linear bearing 14, and the positioning portion is located on the side of the linear bearing 14 away from the eccentric hole. The spring 15 is connected between the connecting rod 16 and the positioning portion to ensure that the guide sleeve 12 can drive the eccentric hole ceramic tube 11 to linearly and elastically expand and contract. The guide sleeve 12 is fixedly connected with a pin rod 19, and the housing 13 is provided with a U-shaped groove extending along the axis direction of the housing 13. The pin is clamped in the U-shaped groove. This makes the pin can only expand and contract in the U-shaped groove, ensuring that the ceramic tube 11 will not rotate relative to the housing 13, and the orientation of the V-shaped positioning groove at the end of the ceramic tube 11 remains unchanged.

[0041] By connecting the assembly and positioning the V-shaped positioning groove at the end of the ceramic tube 11 with the outer cylindrical surface of the head to be welded 17, the welding wire 32 fed through the eccentric hole of the ceramic tube 11 can be located just above the head to be welded 17 and in close contact with the head to be welded 17.

[0042] like Figure 3 As shown, a wire feed hose 31 is provided in the connecting rod 16. The wire feed hose 31 extends from the connecting rod 16 to the joint between the guide sleeve 12 and the eccentric hole of the eccentric hole ceramic tube 11. The welding wire 32 passes through the wire feed hose 31, and then the exposed welding wire 32 passes through the eccentric hole of the eccentric hole ceramic tube 11 so that the end of the welding wire 32 reaches above the head to be welded 17. The weld spot size of the head to be welded 17 is (Φ1mm ~ Φ3mm), the diameter of the welding wire 32 is (0.3mm ~ 0.5mm), the diameter of the wire feed hose 31 is 0.2mm larger than the diameter of the welding wire 32, and the diameter of the eccentric hole of the eccentric ceramic tube 11 is 0.2mm larger than the diameter of the welding wire 32.

[0043] When welding, ensure that the wire feeding angle used is 0°, that is, the welding wire 32 is fed horizontally to the top of the head to be welded 17. This can avoid the problem of the front end of the welding wire 32 pressing against the head to be welded 17 and causing wire blockage when the wire feeding speed and the melting of the welding wire 32 do not match. In addition, the welding wire 32 should extend out of the mouth of the eccentric hole ceramic tube 11 (1mm~2mm) to ensure that the welding wire 32 is in close contact with the head to be welded 17 after the eccentric hole ceramic tube 11 and the head to be welded 17 are positioned. In addition, instead of reversing the wire feeding gear 4 to make the welding wire 32 retract, the welding wire 32 is separated from the molten pool of the weld point of the head to be welded 17. Instead, during the laser heating process, the welding wire 32 is separated from the molten pool of the weld point of the head to be welded 17 by moving the elastic wire feeding nozzle 1 as a whole. This can avoid the problem of the irregular shape of the end of the welding wire 32 that may be formed after the melting of the welding wire 32 getting stuck in the inner hole of the eccentric hole ceramic tube 11 during the retraction of the welding wire 32, causing wire blockage.

[0044] A method for conveying thin and soft welding wire to achieve laser brazing of micro joints comprises the following steps:

[0045] Place the elastic wire feeding nozzle 1 at the same height as the head to be welded 17, then move the elastic wire feeding nozzle 1 horizontally until the V-shaped groove abuts against the head to be welded 17, while the laser 6 irradiates the upper surface of the head to be welded 17.

[0046] When the welding wire 32 is delivered to the surface of the head 17 to be welded for a sufficient length, the entire machine body is moved horizontally away from the head 17 to separate the welding wire 32 from the weld joint.

[0047] The technologies not disclosed in the present invention are common knowledge to those skilled in the art.

[0048] Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims of the present invention.

Claims

1. A structure for realizing laser brazing of micro joints by conveying soft and fine welding wires, characterized in that: including a body that can move horizontally, equipped with a laser (6) for melting the welding wire (32) and a wire winding roller (5); an elastic wire feeding nozzle (1) connected to the body and driven by the body to move vertically, including: a housing (13) connected to the body; a ceramic tube (11) whose one end is slidably connected to the housing (13) along a straight line direction, and the other end is provided with an eccentric hole for positioning the end of the welding wire (32) and a V-shaped groove for positioning the joint to be welded (17). The welding wire (32) passes through the housing (13), the ceramic tube (11), and the eccentric hole in sequence from the wire winding roller (5); the eccentric hole is located directly above the V-shaped groove; the joint to be welded (17) is a shaft structure with an intersecting hole and a cylindrical pin installed in the intersecting hole; the shaft structure is horizontally arranged, and the opening side of the V-shaped groove is in circumferential contact positioning with the arc of the shaft structure; a connection assembly for driving the ceramic tube (11) to move in the direction of extending out of the housing (13); the connection assembly includes a guide sleeve (12), a linear bearing (14), and an elastic member. The guide sleeve (12) is fixedly connected to the ceramic tube (11), the linear bearing (14) is fixedly connected inside the housing (13), the guide sleeve (12) is slidably connected to the inner side of the linear bearing (14), and the elastic member is connected between the housing (13) and the end of the guide sleeve (12) located inside the housing (13); the end of the guide sleeve (12) located inside the housing (13) is provided with a positioning portion, the outer diameter of the positioning portion is larger than the inner diameter of the linear bearing (14), and the positioning portion is located on the side of the linear bearing (14) away from the eccentric hole.

2. The structure for realizing laser brazing of a tiny joint by conveying a soft and fine welding wire according to claim 1, wherein: A connecting rod (16) is connected to the end of the housing (13) away from the ceramic tube (11), and the elastic member is connected to the connecting rod (16).

3. A structure for realizing laser brazing of a micro-joint by conveying a soft and fine welding wire according to claim 2, characterized in that: The connecting rod (16) is connected to the body through a displacement adjusting rod (2); the displacement adjusting rod (2) includes an angle adjusting rod (22) and a height adjusting rod (21) that are hinged to each other. The angle adjusting rod (22) is connected to the connecting rod (16), and the height adjusting rod (21) is connected to the body.

4. A structure for realizing laser brazing of a tiny joint by conveying a soft and fine welding wire according to claim 1, characterized in that: The guide sleeve (12) is fixedly connected with a pin rod (19), and the housing (13) is provided with a U-shaped groove extending along the axis direction of the housing (13), and the pin is clamped in the U-shaped groove.

5. The structure for realizing laser brazing of a micro-joint by conveying a soft and fine welding wire according to claim 2, wherein: A wire feeding hose (31) is arranged inside the connecting rod (16), and the wire feeding hose (31) extends from inside the connecting rod (16) to the butt joint of the guide sleeve (12) and the eccentric hole of the ceramic tube (11); The diameter of the wire feeding hose (31) is (0.1 - 0.3) mm larger than the diameter of the welding wire (32), and the diameter of the eccentric hole of the ceramic tube (11) is (0.1 - 0.2) mm larger than the diameter of the welding wire (32).

6. A method for realizing laser brazing of micro joints by conveying soft and fine welding wires, characterized in that: Using the structure for realizing laser brazing of a micro joint by conveying a soft welding wire according to any one of claims 1-5, including placing the elastic wire feeding nozzle (1) at the same height as the joint to be welded (17), and then horizontally moving the elastic wire feeding nozzle (1) until the V-shaped groove abuts against the joint to be welded (17), and at the same time, the laser (6) irradiates the welding part on the upper surface of the joint to be welded (17); When the length of the welding wire (32) sent to the surface of the joint to be welded (17) is sufficient, horizontally move the body in the direction away from the joint to be welded (17).

7. A method for realizing laser brazing of a micro-joint by conveying a soft and fine welding wire, according to claim 6, characterized in that: The wire feeding inclination angle of the welding wire (32) is 0-5°.

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