Center wire / powder feeding laser welding head with air knife protection and welding method of center wire / powder feeding laser welding head

Abstract

The invention relates to a laser welding head, and aims to solve the technical problem that dust easily enters the laser welding head in the welding process to damage optical devices in the laser welding head. According to the center wire feeding / powder feeding laser welding head with the air knife protection function and the welding method of the center wire feeding / powder feeding laser welding head, an upper opening of a second optical channel is of an inverted-cone-shaped structure, and a first air knife of a hollow structure is embedded in the inverted-cone-shaped structure; a first sealing ring abutting against the lower bottom face of the fixing base is arranged on the upper surface of the first air knife. The outer side face of the first air knife is provided with a plurality of vertically-through first air passing grooves, and a plurality of first air channels are formed between the first air passing grooves and the upper opening of the second optical channel. The lower parts of the plurality of first air channels are respectively communicated with the second optical channel; a first air inlet pipeline which is communicated with an external air source and is communicated with the upper parts of the plurality of first air ducts is arranged in the fixed seat; the multiple laser beams intersect with the welding material in the welding material channel at a laser convergent point along the axes of the multiple optical channels.

Description

Technical Field

[0001] The invention relates to a laser welding head, in particular to a central wire feeding / powder feeding laser welding head with air knife protection and a welding method thereof. Background Art

[0002] Compared with traditional welding methods, laser welding has the characteristics of small heat input, small workpiece deformation, fast speed, high precision, wide application of materials, and flexible processing. It is increasingly widely used in the automotive industry, shipbuilding industry, nuclear power industry, aerospace industry, etc. At the beginning of laser welding application, it was mainly single laser welding, but single laser welding has very high requirements for the assembly gap of the weld, usually less than 0.5mm.

[0003] In recent years, the laser welding process has developed filler wire welding, which has greatly reduced the assembly gap requirements of the workpiece, and the gap between the welding plates can be expanded to 1-2mm. However, most of the existing filler wire welding is side wire feeding, and the welding wire is fed into the laser welding point from one side of the welding head. Side wire feeding takes up a certain space. In many cases, the wire feeding mechanism will interfere with the welded parts, making welding difficult to implement. Side wire feeding is directional and has certain restrictions on the direction of welding movement. Especially when welding medium and thick plates, the penetration ability of the laser is limited, and a deeper welding groove needs to be made in advance. It is not convenient for side wire feeding to enter the bottom of the groove, and the welding efficiency is low.

[0004] For example, the Prest laser internal wire feeding welding head converts a laser beam into a circular beam and passes the welding wire through the middle of the circular beam, thereby achieving the beam surrounding the wire. Although the influence of side wire feeding on the welding process is solved, due to the use of complex beam transformation, special optical lenses and precision mechanical brackets need to be designed, the structure is extremely complex and the manufacturing cost is high; in addition, a large amount of smoke and dust will be generated during the laser welding process. Once the smoke and dust enter the welding head, it is easy to damage the optical devices inside the welding head. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problem that dust easily enters the interior of a laser welding head during welding and causes damage to the optical components inside the laser welding head, and to provide a central wire feeding / powder feeding laser welding head with air knife protection and a welding method thereof.

[0006] The inventive concept of the present invention is as follows: the welding wire reaches the surface to be welded of the base material to be welded from the welding material channel at the center of the welding head, and multiple independent laser beams converge with the welding wire on the surface to be welded of the base material to be welded at a certain angle, so that the welding wire and the base material to be welded can be melted at the same time to achieve welding.

[0007] In order to achieve the above invention objectives and complete the above invention concepts, the technical solutions provided by the present invention are as follows:

[0008] The central wire / powder feeding laser welding head with air knife protection is special in that:

[0009] It includes a fixed seat and an air knife assembly fixedly connected below the fixed seat;

[0010] The fixing seat is provided with a first welding material channel running through the center, and a plurality of first light channels evenly distributed around the circumference of the axis of the first welding material channel;

[0011] The air knife assembly comprises an air knife assembly body installed below the fixing seat; the air knife assembly body is provided with a second welding material channel coaxial with the first welding material channel, and a plurality of second light channels evenly distributed around the circumference of the axis of the second welding material channel and coaxial with the first light channels respectively;

[0012] The upper opening of the second light channel is an inverted cone structure, and a first air knife of a hollow structure is embedded in the inverted cone structure; a first sealing ring abutting against the lower bottom surface of the fixing seat is arranged on the upper surface of the first air knife; a plurality of first air passage grooves penetrating from top to bottom are arranged on the outer side surface of the first air knife, and a plurality of first air ducts are formed between the first air passage grooves and the upper opening of the second light channel; and the lower parts of the plurality of first air ducts are respectively connected with the second light channel;

[0013] A first air inlet pipeline is arranged in the fixing seat, which is in communication with an external air source and is in communication with the tops of the plurality of first air ducts;

[0014] The first welding material channel and the second welding material channel constitute a welding material channel; the first light channel and the second light channel constitute a light channel; and a plurality of laser beams intersect with the welding materials in the welding material channel at a laser convergence point along the axes of the plurality of light channels respectively.

[0015] Furthermore, a connecting base is provided below the fixing seat, and the connecting base includes a connecting base body, and the connecting base body is provided with an intermediate welding material channel coaxial with the first welding material channel, and a plurality of intermediate light channels evenly distributed around the circumference of the axis of the intermediate welding material channel and coaxial with the first light channel respectively;

[0016] The upper opening of the middle light channel is an inverted cone structure, and a second air knife of a hollow structure is embedded in the inverted cone structure; the upper surface of the second air knife is provided with a second sealing ring abutting against the lower bottom surface of the fixing seat; the outer side surface of the second air knife is provided with a plurality of second air passage grooves penetrating from top to bottom, and a plurality of second air ducts are formed between the second air passage grooves and the upper opening of the middle light channel; the lower parts of the plurality of second air ducts are respectively connected with the middle light channel;

[0017] The air knife assembly body is connected to the lower surface of the connecting base body, and the first sealing ring is in contact with the lower bottom surface of the connecting base body;

[0018] The first air inlet pipeline is located in the connecting base body;

[0019] A second air inlet pipeline is arranged in the fixing seat, which is in communication with an external air source and is in communication with the upper parts of the plurality of second air ducts;

[0020] The first welding material channel, the middle welding material channel and the second welding material channel constitute the welding material channel; the first light channel, the middle light channel and the second light channel constitute the light channel.

[0021] Furthermore, the air knife assembly body is provided with a plurality of first protective air passages and second protective air passages which are evenly distributed around the circumference of the second welding material channel axis and are in communication with each other;

[0022] The first protective air duct is communicated with the first air inlet pipeline, and the second protective air duct opens into the second light channel to form a transverse air curtain.

[0023] Furthermore, the air knife assembly also includes a welding material pipe limiting tube and a protective nozzle; the laser convergence point is located 20 to 30 mm below the protective nozzle;

[0024] The welding material pipe limiting pipe is installed at the lower end of the second welding material channel, and the outlet of the welding material pipe limiting pipe is flush with the outlet of the second welding material channel;

[0025] The shielding nozzle is installed at the outlet of the second welding material channel;

[0026] It also includes a welding material pipe that passes through the first welding material channel, the middle welding material channel, the second welding material channel, the welding material pipe limiting pipe and the protective nozzle in sequence from top to bottom, and the lower end surface of the welding material pipe is flush with the surface where the outlet of the protective nozzle is located; the upper end of the welding material pipe is installed on the top of the fixing seat through a flange;

[0027] The first welding material channel comprises an upper section of the first welding material channel and a lower section of the first welding material channel; the diameter of the upper section of the first welding material channel is 0.5-1 mm smaller than the diameter of the lower section of the first welding material channel; the diameters of the intermediate welding material channel, the second welding material channel and the lower section of the first welding material channel are the same, the inner diameter of the welding material pipe limiting pipe is the same as that of the upper section of the first welding material channel, and a plurality of third gas passage grooves evenly distributed around the circumference are opened on its outer wall;

[0028] A gas passage is formed between the outer wall of the welding material pipe and the lower section of the first welding material passage, the middle welding material passage, the second welding material passage, the third gas passage groove, and the inner wall of the protective nozzle;

[0029] A third protective gas channel which is in communication with an external inert gas source and is in communication with the gas passage is arranged in the fixing seat.

[0030] Furthermore, a plurality of protective lens group mounting holes for mounting the protective lens group are provided on the side of the fixing seat; the protective lens group mounting holes correspond one to one with the first optical channels;

[0031] The protective lens group includes a protective lens and a protective lens seat, and the protective lens seat is slidably installed in the protective lens group installation hole;

[0032] A stepped light-transmitting hole is provided on the protective mirror seat, and the protective mirror is installed on the step of the stepped light-transmitting hole;

[0033] A protective mirror sealing ring is provided on the top of the protective mirror, the bottom of the protective mirror sealing ring is in contact with the protective mirror, and the side of the protective mirror sealing ring is in contact with the inner wall of the stepped light transmission hole;

[0034] A handle is provided on one side of the protective mirror seat. The handle is fixed on the outer side wall of the fixing seat by screws. A handle sealing ring is provided between the side wall of the handle and the fixing seat.

[0035] Furthermore, the lower part of the main body of the wind knife assembly is sequentially sleeved with a window protection plate, a rubber pad and a protection plate retaining ring from top to bottom;

[0036] The protection plate retaining ring is threadedly connected to the main body of the air knife assembly;

[0037] The window protection plate is provided with an arc-shaped limit hole, and a third light channel which is evenly distributed along the circumference of the axis of the window protection plate and is equal to the second light channel;

[0038] The lower surface of the wind knife assembly body is provided with a limiting boss adapted to the arc-shaped limiting hole; when the window protection plate rotates, the limiting boss can slide in the arc-shaped limiting hole;

[0039] When the limiting boss is located at one end of the arc-shaped limiting hole, the third light channel corresponds to the second light channel one by one, and the axis of the third light channel coincides with the axis of the corresponding second light channel;

[0040] When the limiting boss is located at the other end of the arc-shaped limiting hole, the third light channel is completely misaligned with the second light channel;

[0041] The bottom of the air knife assembly body is provided with a plurality of transverse air outlet grooves which are evenly distributed around the axis of the second welding material channel and correspond to the position of the first protective air duct. The transverse air outlet grooves are connected to the first protective air duct, and the second protective air duct is formed between the transverse air outlet grooves and the window protection plate.

[0042] Furthermore, the first air inlet pipeline includes a fourth protective air duct which is opened in the connection base body and communicates with an external air source;

[0043] A first annular groove is formed on the upper surface of the air knife assembly body around the axis of the second welding material channel, and a first annular air duct is formed between the first annular groove and the lower surface of the connecting base body, and the first annular air duct is communicated with the fourth protective air duct, the first air duct and the first protective air duct;

[0044] The second air inlet pipeline includes a fifth protective air duct opened in the fixing seat and communicating with an external air source;

[0045] A second annular groove is provided on the upper surface of the connecting base body around the axis of the middle welding material channel, and a second annular air duct is formed between the second annular groove and the lower surface of the fixing seat, and the second annular air duct is communicated with the fifth protective air duct and the second air duct.

[0046] Furthermore, a plurality of first water channels connected to a circulating cooling water source are provided on the side of the fixing seat;

[0047] A second water channel is also provided on the side of the air knife assembly body;

[0048] The second water channel includes an L-shaped water channel and a water channel sealing plate sleeved on the outside of the air knife assembly body; the horizontal section of the water channel is connected to the circulating cooling water source, and the vertical section runs through the bottom of the air knife assembly body;

[0049] The water channel sealing plate is fixedly installed on the bottom of the air knife assembly body by multiple screws, and an annular water groove corresponding to the vertical section of the water channel is opened on the water channel sealing plate;

[0050] A third sealing ring and a fourth sealing ring are arranged between the water channel sealing plate and the wind knife assembly body. The inner diameter of the third sealing ring is larger than the outer diameter of the annular water tank, and the outer diameter of the fourth sealing ring is smaller than the inner diameter of the annular water tank.

[0051] At the same time, the present invention also provides a central wire feeding / powder feeding laser welding method with air knife protection, which is special in that it includes the following steps:

[0052] S1. Prepare the above-mentioned central wire feeding / powder feeding laser welding head with air knife protection;

[0053] S2. Connect the central wire feeding / powder feeding laser welding head with air knife protection to the welding equipment and complete the welding preparation work;

[0054] S3, connecting the first air inlet pipeline to an external air source, so that the gas from the external air source enters the first air duct through the first air inlet pipeline and forms a positive pressure environment at the lower end of the second optical channel;

[0055] S4, causing the multiple laser beams to be emitted along the multiple optical channels respectively and converged at the laser convergence point;

[0056] S5. Send the welding material from the welding material channel to the laser convergence point through the feeding equipment;

[0057] S6. Adjust the position of the laser welding head through the welding equipment so that the laser convergence point is located on the surface to be welded of the base material to be welded, and adjust the gap between the base materials to be welded according to the welding requirements;

[0058] S7, the base material to be welded and the welding material absorb the energy of the laser beam and melt to form a molten pool and liquid welding material respectively;

[0059] S8. Move the laser welding head through the welding equipment to move the laser convergence point away from the liquid welding material, and the liquid welding material cools rapidly to form a welding seam, thus completing the welding of the base material to be welded.

[0060] Further, in step S2, the welding preparation work is completed specifically as follows:

[0061] S2.1. Install multiple laser sources at the corresponding positions of each optical channel on the top of the fixing base;

[0062] S2.2. Rotate the window protection plate to place the limiting boss at one end of the arc-shaped limiting hole so that the axis of the third light channel coincides with the axis of the second light channel;

[0063] S2.3, connect the fifth protective air duct to an external air source, and the external air source injects gas into the second annular air duct and the second air duct through the fifth protective air duct to create a positive pressure environment at the lower end of the middle optical channel;

[0064] S2.4, connecting the third protective gas channel to an external inert gas source, the external inert gas source injects the inert gas into the gas passage through the third protective gas channel, and sprays the inert gas from between the protective nozzle and the welding material pipe to form an annular gas curtain;

[0065] S2.5. Connect the circulating cooling water source to the first water channel and the second water channel respectively;

[0066] Step S3 specifically includes: connecting the fourth protective air duct with an external air source, allowing the gas from the external air source to enter the first annular air duct through the fourth protective air duct, and a portion of the gas is ejected from the first air duct to the lower end of the second optical channel to create a positive pressure environment at the lower end of the second optical channel; another portion of the gas is ejected from the first protective air duct and the second protective air duct at the outlet of the second optical channel to form a horizontal air curtain;

[0067] Step S4 specifically includes making the multiple laser beams emit along the multiple first optical channels, the middle optical channels, the second optical channels, and the third optical channels respectively, and converge at the laser convergence point;

[0068] Step S5 specifically includes: feeding the welding material from the welding material tube to the laser convergence point by means of a feeding device;

[0069] In step S6, the thickness of the base material to be welded is greater than 5 mm, and the gap is greater than 0.5 mm;

[0070] In step S8, the moving speed of the welding equipment is greater than 1 m / min.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] 1. The central wire feeding / powder feeding laser welding head with air knife protection provided by the present invention, the welding material reaches the welding surface of the base material to be welded from the welding material channel located in the middle of the laser welding head, and then multiple independent laser beams are used to converge with the welding material on the welding surface of the base material to be welded at a certain angle, and multiple lasers can melt the welding material and the base material to be welded at the same time to achieve welding; because multiple laser sources are directly used to provide multiple laser beams, the complex mechanical structure and optical components for converting a single laser beam into a ring laser beam are avoided, and the mechanical structure of the laser welding head is simplified; at the same time, the processing and manufacturing cost of the laser welding head is about 1 / 5-1 / 10 of the manufacturing cost of the existing similar technology, which is easier to realize industrial application, making the structure of the laser welding head more simple, safe and reliable. At the same time, through the first air duct formed between the first air groove on the outer surface of the first air knife and the opening on the second optical channel, when the gas of the external gas source enters the first air duct from the first air inlet pipeline and is transported from the bottom of the first air duct to the second optical channel, a positive pressure environment is formed at the lower end of the second optical channel to prevent dust from entering the laser welding head from the second optical channel.

[0073] 2. The central wire feeding / powder feeding laser welding head with air knife protection and the welding method thereof provided by the present invention, when the gas from the external gas source enters the first annular air duct from the fourth protective air duct, a part of the gas is ejected from the first air duct to the lower end of the second optical channel, and a positive pressure environment is created at the lower end of the second optical channel; another part of the gas is ejected from the first protective air duct and the second protective air duct at the outlet of the second optical channel, and a transverse air curtain is formed. By forming a positive pressure environment and a transverse air curtain at the outlet of the second optical channel, dust is prevented from entering the interior of the laser welding head from the second optical channel. By setting up the fifth protective air duct, when the gas from the external gas source enters the second annular air duct from the fifth protective air duct, the gas is ejected from the second air duct to the lower end of the middle optical channel, and a positive pressure environment is created at the lower end of the middle optical channel; dust can be effectively prevented from entering the laser welding head from the second optical channel.

[0074] 3. In the central wire feeding / powder feeding laser welding head with air knife protection provided by the present invention, the bottom of the air knife component body is a round and thin rod-shaped structure. During the welding process, it occupies less space and can be used for welding in narrow spaces. At the same time, since the round and thin rod-shaped structure at the bottom of the air knife component body is close to the molten pool during the welding process, a second water channel is arranged near the round and thin rod-shaped structure at the bottom of the air knife component body, and the heat dissipation effect of the round and thin rod-shaped structure can be improved by injecting circulating cooling water into the second water channel.

[0075] 4. The central wire feeding / powder feeding laser welding head with wind knife protection provided by the present invention has an independent laser beam that intersects the welding material in the welding material channel at the laser convergence point along the axis of the light channel. Since the light channel is evenly distributed, the welding material is heated more evenly during the welding process; and multiple independent laser sources are used, and the laser power of the laser source can be adjusted to achieve laser power welding of tens of thousands of watts, which is suitable for welding of medium and thick plates. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0077] Figure 2 This is a schematic diagram of the structure of the welding material tube and the protective lens assembly installed in the embodiment of the present invention;

[0078] Figure 3 It is a schematic diagram of the structure of an embodiment of the present invention in a working state.

[0079] Figure 4 Schematic diagram of the structure of the second air knife in an embodiment of the present invention;

[0080] Figure 5 It is a partial enlarged structural schematic diagram of the first wind knife and the second wind knife in an embodiment of the present invention;

[0081] Figure 6 It is a schematic diagram of the structure of the third protection air channel, the fourth protection air channel, the fifth protection air channel, the first water channel and the second water channel in an embodiment of the present invention;

[0082] Figure 7 It is a schematic cross-sectional view of a welding material pipe limiting pipe in an embodiment of the present invention;

[0083] Figure 8 It is a schematic diagram of a partially enlarged structure of a welding material pipe limiting pipe in an embodiment of the present invention;

[0084] Fig. 9 A top view of the protective mirror holder and the handle in an embodiment of the present invention;

[0085] Fig.10 A bottom view of an embodiment of the present invention;

[0086] Fig.11 It is a schematic diagram of a partially enlarged structure of the second water channel in an embodiment of the present invention;

[0087] Description of the accompanying drawings: 1-fixed seat, 11-first light channel, 12-first welding material channel, 121-upper section of the first welding material channel, 122-lower section of the first welding material channel, 13-laser convergence point, 14-mounting hole of the protective mirror group, 15-first water channel, 16-third protective air channel, 17-fifth protective air channel, 171-second air channel, 172-second annular air channel, 2-protective mirror group, 21-handle sealing ring, 22-protective mirror sealing ring, 23-protective mirror, 24-protective mirror seat, 25-handle, 3-connecting base, 31-fifth sealing ring, 32-second sealing ring, 33-sixth sealing ring, 34-connecting base body, 341-middle light channel, 342-middle welding material channel, 35-second air knife, 351-second air passage groove, 36-fourth protective air channel, 361-first air channel, 362-first annular air duct, 4-air knife assembly, 41-seventh sealing ring, 42-first sealing ring, 43-eighth sealing ring, 44-air knife assembly body, 441-second optical channel, 442-second welding material channel, 443-limiting boss, 45-first protective air duct, 46-second protective air duct, 47-welding material pipe limiting pipe, 471-third air passage, 48-protection nozzle, 49-second water channel, 491-water channel, 492-water channel sealing plate, 493-third sealing ring, 494-fourth sealing ring, 495-annular water trough, 410-first air knife, 5-welding material pipe, 51-ninth sealing ring, 52-flange, 6-window protection plate, 61-rubber pad, 62-third optical channel, 63-arc-shaped limiting hole, 7-protection plate retaining ring, 8-laser beam, 9-welding material, 10-parent material to be welded. DETAILED DESCRIPTION

[0088] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0089] like Figure 1 and Figure 3 As shown, the present invention discloses a central wire feeding / powder feeding laser welding head with air knife protection. By opening a welding material channel located in the middle of the laser welding head, the welding material 9 can reach the surface of the base material 10 to be welded through the welding material channel in the center of the laser welding head, so as to realize the central wire / powder discharge, avoid the problem of large space occupied by the side wire feeding / powder feeding during the welding process, so that the weld can move freely in all directions, greatly improving the convenience and efficiency of welding; at the same time, the present invention adopts multiple laser sources, and opens multiple light channels evenly distributed around the circumference of the axis of the welding material channel on the laser welding head, such as Figure 2As shown, multiple independent laser beams 8 intersect the welding material 9 in the welding material channel at the laser convergence point 13 along the axes of multiple light channels respectively. The welding material 9 and the parent material 10 to be welded can be melted at the same time by the multiple laser beams 8 to achieve welding, and the multiple laser beams 8 are evenly distributed around the welding material 9, so that the welding material 9 is evenly heated.

[0090] like Figure 1 and Figure 3 As shown, the present invention discloses a central wire feeding / powder feeding laser welding head with air knife protection, comprising a fixed seat 1 and an air knife assembly 4 fixedly connected to the bottom of the fixed seat 1; a first welding material channel 12 running through the center and a plurality of first optical channels 11 uniformly distributed around the axis of the first welding material channel 12 are opened in the fixed seat 1; the air knife assembly 4 comprises an air knife assembly body 44 installed below the fixed seat 1; a second welding material channel 442 coaxial with the first welding material channel 12 and a plurality of second optical channels 441 uniformly distributed around the axis of the second welding material channel 442 and respectively coaxial with the first optical channel 11 are opened on the air knife assembly body 44; the first welding material channel 12 and the second welding material channel 442 constitute a welding material channel; the first optical channel 11 and the second optical channel 441 constitute an optical channel; a plurality of laser beams 8 intersect with the welding material 9 in the welding material channel along the axes of the plurality of optical channels at a laser convergence point 13, and the laser convergence point 13 is located 20 to 30 mm below the protective mouth 48.

[0091] like Figure 1 As shown, in order to prevent external dust from entering the optical channel of the laser welding head during the laser welding process and causing damage to the internal optical devices of the laser welding head; the upper opening of the second optical channel 441 is set to an inverted cone structure, and a first air knife 410 with a hollow structure is embedded in the inverted cone structure; the first air knife 410 has the same structure as the second air knife 35, and the structure of the second air knife 35 is detailed in Figure 4 The upper surface of the first wind knife 410 is provided with a first sealing ring 42 abutting against the lower bottom surface of the fixing seat 1; the outer side surface of the first wind knife 410 is provided with a plurality of first air passage grooves which pass through from top to bottom, and a plurality of first air ducts 361 are formed between the first air passage grooves and the upper opening of the second light channel 441; the lower parts of the plurality of first air ducts 361 are respectively connected with the second light channel 441; at the same time, a first air inlet pipeline which is connected with an external air source and connected with the upper parts of the plurality of first air ducts 361 is provided in the fixing seat 1 to provide an air source for the first air duct 361.

[0092] In order to prevent dust from entering the light channel, a horizontal air curtain can also be set up, that is: Figure 6 As shown, the air knife assembly body 44 is provided with a plurality of first protective air ducts 45 and second protective air ducts 46 that are evenly distributed and interconnected around the axis of the second welding material channel 442; the first protective air duct 45 is connected to the first air inlet pipeline, and the second protective air duct 46 opens into the second light channel 441 to form a transverse air curtain.

[0093] In this embodiment, if Figure 1 As shown, the structure of the laser welding head can also be:

[0094] A connecting base 3 is arranged below the fixing seat 1, and the connecting base 3 includes a connecting base body 34, on which is provided an intermediate welding material channel 342 coaxial with the first welding material channel 12, and a plurality of intermediate light channels 341 evenly distributed around the axis of the intermediate welding material channel 342 and coaxial with the first light channel 11; a wind knife assembly main body 44 is connected to the lower surface of the connecting base body 34, and a first sealing ring 42 abuts against the lower bottom surface of the connecting base body 34; and the first air inlet duct is located in the connecting base body 34.

[0095] Among them, Figure 6 As shown, the first air inlet pipeline includes a fourth protective air duct 36 opened in the connection base body 34 and communicating with the external air source; Figure 5 As shown, a first annular groove is provided on the upper surface of the air knife assembly body 44 around the axis of the second welding material channel 442 , and a first annular air duct 362 is formed between the first annular groove and the lower surface of the connecting base body 34 , and the first annular air duct 362 is communicated with the fourth protective air duct 36 , the first air duct 361 and the first protective air duct 45 .

[0096] The external gas source is used to provide high-pressure air or high-pressure inert gas. Figure 6 As shown, the high-pressure air or high-pressure inert gas in the external air source enters the first annular air duct 362 through the fourth protective air duct 36, as shown in FIG. Figure 5 As shown, a part of the high-pressure air or high-pressure inert gas enters the second light channel 441 along the first air duct 361, forming a positive pressure environment at the lower end of the second light channel 441; another part of the high-pressure air or high-pressure inert gas is ejected along the first protective air channel 45 and the second protective air channel 46, and forms a horizontal air curtain at the lower opening of the second light channel 441.

[0097] The first welding material channel 12, the middle welding material channel 342 and the second welding material channel 442 constitute the welding material channel; the first light channel 11, the middle light channel 341 and the second light channel 441 constitute the light channel; Figure 3 As shown, a plurality of laser beams 8 intersect the welding material 9 in the welding material channel at a laser convergence point 13 along the axes of a plurality of light channels respectively.

[0098] like Figure 2 As shown, the upper opening of the middle light channel 341 is an inverted cone structure, and a second air knife 35 with a hollow structure is embedded in the inverted cone structure; the structure of the second air knife 35 is as shown in FIG. Figure 4As shown, the upper surface of the second air knife 35 is provided with a second sealing ring 32 that abuts against the lower bottom surface of the fixing base 1; the outer side surface of the second air knife 35 is provided with a plurality of second air passage grooves 351 that pass through from top to bottom, as shown in FIG. Figure 1 As shown, a plurality of second air ducts 171 are formed between the second air passage 351 and the upper opening of the middle light channel 341; the lower parts of the plurality of second air ducts 171 are respectively connected to the middle light channel 341; a second air inlet pipeline is arranged in the fixing seat 1, which is connected to an external air source and connected to the upper parts of the plurality of second air ducts 171.

[0099] Among them, Figure 6 As shown, the second air inlet pipeline includes a fifth protective air duct 17 opened in the fixing base 1 and communicating with the external air source; Figure 1 and Figure 5 As shown, a second annular groove is provided on the upper surface of the connecting base body 34 around the axis of the middle welding material channel 342 , and a second annular air duct 172 is formed between the second annular groove and the lower surface of the fixing seat 1 , and the second annular air duct 172 is communicated with the fifth protective air duct 17 and the second air duct 171 .

[0100] During use, high-pressure air or high-pressure inert gas from an external air source enters the second annular air duct 172 from the fifth protective air duct 17 and enters the middle light channel 341 from the second air duct 171, forming a positive pressure environment at the lower end of the middle light channel 341.

[0101] like Figure 1 , Figure 2 and Figure 3 As shown, the air knife assembly 4 also includes a welding material tube limiting tube 47 and a protective nozzle 48; the welding material tube limiting tube 47 is installed at the lower end of the second welding material channel 442, and the outlet of the welding material tube limiting tube 47 is flush with the outlet of the second welding material channel 442; Figure 8 As shown, the protection nozzle 48 is installed at the outlet of the second welding material channel 442; it also includes a welding material pipe 5 that passes through the first welding material channel 12, the middle welding material channel 342, the second welding material channel 442, the welding material pipe limiting pipe 47 and the protection nozzle 48 from top to bottom, and the lower end surface of the welding material pipe 5 is flush with the surface where the outlet of the protection nozzle 48 is located; the upper end of the welding material pipe 5 is installed on the top of the fixing seat 1 through the flange 52. A ninth sealing ring 51 is provided between the flange 52 and the fixing seat 1.

[0102] like Figure 1As shown, in order to fix the position of the welding material pipe 5 in the welding material channel and prevent the welding material pipe 5 from shaking, the following conditions should be met: the length of the upper section 121 of the first welding material channel is 10-15mm; the diameter of the upper section 121 of the first welding material channel is 0.5-1mm smaller than the diameter of the lower section 122 of the first welding material channel; the diameter of the middle welding material channel 342, the second welding material channel 442 and the lower section 122 of the first welding material channel are the same, the inner diameter of the welding material tube limiting tube 47 is the same as that of the upper section 121 of the first welding material channel, and the length of the welding material tube limiting tube 47 is 10-15mm.

[0103] In order to protect the welding point between the welding material 9 and the base material 10 to be welded during the welding process, Figure 7 As shown, a plurality of third gas passage grooves 471 evenly distributed around the circumference are provided on the outer wall of the welding material pipe limit tube 47; a gas passage is formed between the outer wall of the welding material pipe 5 and the lower section 122 of the first welding material channel, the middle welding material channel 342, the second welding material channel 442, the third gas passage groove 471, and the inner wall of the protective nozzle 48; a third protective gas passage 16 communicating with an external inert gas source and communicating with the gas passage is provided in the fixing seat 1. During use, the inert protective gas enters the gas passage from the third protective gas passage 16, and the inert protective gas is ejected from between the protective nozzle 48 and the welding material pipe 5, and the ejected inert protective gas is an annular gas curtain.

[0104] In order to prevent dust from reaching the laser source along the optical path during laser welding, Figure 3 As shown, a plurality of protective mirror groups 2 are provided corresponding to the first optical channels 11 one by one, such as Figure 1 As shown, a plurality of protective lens group mounting holes 14 for mounting the protective lens group 2 are provided on the side of the fixing seat 1; the protective lens group mounting holes 14 correspond one-to-one to the first optical channel 11; the protective lens group 2 includes a protective lens 23 and a protective lens seat 24, and the protective lens seat 24 is slidably installed in the protective lens group mounting hole 14; a stepped light-transmitting hole is provided on the protective lens seat 24, and the protective lens 23 is installed on the step of the stepped light-transmitting hole; a protective lens sealing ring 22 is provided on the top of the protective lens 23, the bottom of the protective lens sealing ring 22 is in contact with the protective lens 23, and the side of the protective lens sealing ring 22 is in contact with the inner wall of the stepped light-transmitting hole; a handle 25 is provided on one side of the protective lens seat 24, and the handle 25 is fixedly installed on the outer wall of the fixing seat 1 by screws, and a handle sealing ring 21 is provided between the side wall of the handle 25 and the fixing seat 1.

[0105] In order to ensure that the multiple laser beams 8 can converge at the laser convergence point 13 when the laser welding head is used, and that dust in the air does not enter the optical channel when the laser welding head is not used, Figure 1 and Figure 5 As shown, the window protection plate 6, the rubber pad 61 and the protection plate retaining ring 7 are sequentially sleeved on the lower part of the wind knife assembly body 44 from top to bottom; the protection plate retaining ring 7 is threadedly connected to the wind knife assembly body 44; Fig.10 As shown, the window protection plate 6 is provided with an arc-shaped limit hole 63, and a third light channel 62 which is evenly distributed along the circumference of the axis of the window protection plate 6 and is equal to the second light channel 441; the lower surface of the wind knife assembly body 44 is provided with a limit boss 443 which is adapted to the arc-shaped limit hole 63; the window protection plate 6 is rotated, and the limit boss 443 can slide in the arc-shaped limit hole 63.

[0106] When the limiting boss 443 is located at one end of the arc-shaped limiting hole 63, the third light channel 62 corresponds to the second light channel 441 one by one, and the axis of the third light channel 62 coincides with the axis of the corresponding second light channel 441; at this time, Figure 1 As shown, the laser beam 8 can be emitted from the laser welding head to the laser focusing point 13 .

[0107] When the limiting boss 443 is located at the other end of the arc-shaped limiting hole 63, the third light channel 62 is completely misaligned with the second light channel 441; Figure 2 As shown, the window protection plate 6 closes the light channel, and dust in the air cannot enter the light channel.

[0108] In this embodiment, if Figure 5 As shown, a plurality of transverse air outlet grooves are evenly distributed around the axis of the second welding material channel 442 and corresponding to the position of the first protective air duct 45 at the bottom of the air knife assembly body 44. The transverse air outlet grooves are connected to the first protective air duct 45, and a second protective air duct 46 is formed between the transverse air outlet grooves and the window protection plate 6.

[0109] In order to dissipate heat when the center wire feeding / powder feeding laser welding head is working, Figure 6 As shown, a plurality of first water channels 15 connected to a circulating cooling water source are provided on the side of the fixing seat 1; the first water channels 15 are connected to the circulating cooling water source to dissipate heat through the circulation of cooling water.

[0110] In order to dissipate heat from the round thin rod structure at the bottom of the air knife assembly body 44 on the center wire feeding / powder feeding laser welding head, as shown in FIG. Figure 6 and Fig.11 As shown, a second water channel 49 is also provided on the side of the wind knife assembly body 44; the second water channel 49 includes an L-shaped water channel 491 and a water channel sealing plate 492 which is sleeved on the outside of the wind knife assembly body 44; the horizontal section of the water channel 491 is connected to the circulating cooling water source, and the vertical section passes through the bottom of the wind knife assembly body 44; the water channel sealing plate 492 is fixedly installed on the bottom of the wind knife assembly body 44 by a plurality of screws, and an annular water groove 495 corresponding to the vertical section of the water channel 491 is provided on the water channel sealing plate 492.

[0111] In order to ensure the sealing performance between the water channel sealing plate 492 and the air knife assembly body 44, as shown in FIG. Figure 6 and Fig.11As shown, a third sealing ring 493 and a fourth sealing ring 494 are provided between the water channel sealing plate 492 and the wind knife assembly body 44 . The inner diameter of the third sealing ring 493 is larger than the outer diameter of the annular water groove 495 , and the outer diameter of the fourth sealing ring 494 is smaller than the inner diameter of the annular water groove 495 .

[0112] In this embodiment, in order to ensure the gas sealing performance between the connection base body 34 and the fixing base 1, and between the air knife assembly body 44 and the connection base body 34, as shown in FIG. Figure 2 As shown, a fifth sealing ring 31 and a sixth sealing ring 33 are provided between the connecting base body 34 and the fixing base 1. The fifth sealing ring 31 is embedded in the edge of the upper surface of the connecting base body 34, and the sixth sealing ring 33 is embedded in the outer edge of the middle welding material channel 342; the outer diameter of the second annular air duct 172 is smaller than the inner diameter of the fifth sealing ring 31, and the inner diameter of the second annular air duct 172 is larger than the outer diameter of the sixth sealing ring 33.

[0113] A seventh sealing ring 41 and an eighth sealing ring 43 are provided between the wind knife assembly body 44 and the connecting base body 34. The seventh sealing ring 41 is embedded in the edge of the upper surface of the wind knife assembly body 44, and the eighth sealing ring 43 is embedded in the outer edge of the second welding material channel 442; the outer diameter of the first annular air duct 362 is smaller than the inner diameter of the seventh sealing ring 41, and the inner diameter of the first annular air duct 362 is larger than the outer diameter of the eighth sealing ring 43.

[0114] The specific method of the central wire feeding / powder feeding laser welding with air knife protection of the present invention is:

[0115] S1. Prepare the above-mentioned central wire feeding / powder feeding laser welding head with air knife protection;

[0116] S2. Connect the central wire feeding / powder feeding laser welding head with air knife protection to the welding equipment and complete the welding preparation work;

[0117] S2.1. Install multiple laser sources at the positions corresponding to each optical channel on the top of the fixing base 1;

[0118] S2.2, rotating the window protection plate 6 to place the limiting boss 443 at one end of the arc-shaped limiting hole 63, so that the axis of the third light channel 62 coincides with the axis of the second light channel 441;

[0119] S2.3, connecting the fifth protective air channel 17 to an external air source, and the external air source injects gas into the second annular air channel 172 and the second air channel 171 through the fifth protective air channel 17, so as to create a positive pressure environment at the lower end of the middle optical channel 341;

[0120] S2.4, connecting the third protective gas channel 16 to an external inert gas source, the external inert gas source injects the inert gas into the gas passage through the third protective gas channel 16, and sprays the inert gas from between the protective nozzle 48 and the welding material pipe 5 to form an annular gas curtain;

[0121] S2.5, connecting the circulating cooling water source to the first water channel 15 and the second water channel 49 respectively;

[0122] S3, connect the fourth protection air duct 36 with the external air source, the gas from the external air source enters the first annular air duct 362 through the fourth protection air duct 36, a part of the gas is ejected from the first air duct 361 to the lower end of the second light channel 441, and a positive pressure environment is created at the lower end of the second light channel 441; the other part of the gas is ejected from the first protection air duct 45 and the second protection air duct 46 at the outlet of the second light channel 441, and a horizontal air curtain is formed;

[0123] S4, making the multiple laser beams 8 respectively emit along the multiple first optical channels 11, the middle optical channel 341, the second optical channel 441, and the third optical channel 62, and converge at the laser convergence point 13;

[0124] S5, feeding the welding material 9 from the welding material tube 5 to the laser convergence point 13 by means of a feeding device;

[0125] S6. Adjust the position of the laser welding head by welding equipment so that the laser convergence point 13 is located on the surface of the base material 10 to be welded, and adjust the gap between the base materials 10 to be welded according to welding requirements;

[0126] S7, the base material 10 to be welded and the welding material 9 absorb the energy of the laser beam 8 and melt to form a molten pool and a liquid welding material respectively;

[0127] S8. Move the laser welding head through the welding equipment to move the laser convergence point 13 away from the liquid welding material, and the liquid welding material cools rapidly to form a welding seam, thereby completing the welding of the base material 10 to be welded.

[0128] In this embodiment, the welding equipment is a motion control device such as a robot or a machine tool, and the moving speed of the welding equipment is 1.2 m / min; the thickness of the base material 10 to be welded is 6 mm, and the gap is 0.8 mm.

[0129] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. Central wire feeding / powder feeding laser welding head with air knife protection, characterized by: It comprises a fixed seat (1) and an air knife assembly (4) fixedly connected below the fixed seat (1); The fixing seat (1) is provided with a first welding material channel (12) penetrating the center, and a plurality of first light channels (11) evenly distributed around the axis of the first welding material channel (12); The air knife assembly (4) comprises an air knife assembly body (44) installed below the fixing seat (1); the air knife assembly body (44) is provided with a second welding material channel (442) coaxial with the first welding material channel (12), and a plurality of second light channels (441) uniformly distributed around the axis of the second welding material channel (442) and coaxial with the first light channel (11); The upper opening of the second light channel (441) is an inverted cone-shaped structure, and a first air knife (410) of a hollow structure is embedded in the inverted cone-shaped structure; the upper surface of the first air knife (410) is provided with a first sealing ring (42) that abuts against the lower bottom surface of the fixing seat (1); the outer side surface of the first air knife (410) is provided with a plurality of first air passage grooves that pass through from top to bottom, and a plurality of first air ducts (361) are formed between the first air passage grooves and the upper opening of the second light channel (441); the lower parts of the plurality of first air ducts (361) are respectively connected to the second light channel (441); A first air inlet pipeline is arranged in the fixing seat (1), which is in communication with an external air source and is in communication with the tops of the plurality of first air ducts (361); The first welding material channel (12) and the second welding material channel (442) form a welding material channel; the first light channel (11) and the second light channel (441) form a light channel; and a plurality of laser beams (8) intersect with welding materials (9) in the welding material channel at a laser convergence point (13) along the axes of the plurality of light channels.

2. The central wire feeding / powder feeding laser welding head with air knife protection according to claim 1, characterized in that: A connecting base (3) is arranged below the fixing base (1), the connecting base (3) comprising a connecting base body (34), the connecting base body (34) being provided with an intermediate welding material channel (342) coaxial with the first welding material channel (12), and a plurality of intermediate light channels (341) uniformly distributed around the axis of the intermediate welding material channel (342) and coaxial with the first light channel (11); The upper opening of the middle light channel (341) is an inverted cone-shaped structure, and a second air knife (35) of a hollow structure is embedded in the inverted cone-shaped structure; the upper surface of the second air knife (35) is provided with a second sealing ring (32) that abuts against the lower bottom surface of the fixing seat (1); the outer side surface of the second air knife (35) is provided with a plurality of second air passage grooves (351) that pass through from top to bottom, and a plurality of second air ducts (171) are formed between the second air passage grooves (351) and the upper opening of the middle light channel (341); the lower parts of the plurality of second air ducts (171) are respectively connected to the middle light channel (341); The wind knife assembly body (44) is connected to the lower surface of the connection base body (34), and the first sealing ring (42) is in contact with the lower bottom surface of the connection base body (34); The first air inlet pipeline is located inside the connecting base body (34); A second air inlet pipeline is arranged in the fixing seat (1), which is in communication with an external air source and is in communication with the upper parts of the plurality of second air ducts (171); The first welding material channel (12), the middle welding material channel (342) and the second welding material channel (442) constitute a welding material channel; the first light channel (11), the middle light channel (341) and the second light channel (441) constitute a light channel.

3. The central wire feeding / powder feeding laser welding head with air knife protection according to claim 2, characterized in that: The air knife assembly body (44) is provided with a plurality of first protective air passages (45) and second protective air passages (46) which are evenly distributed around the circumference of the axis of the second welding material passage (442) and communicate with each other; The first protective air duct (45) is in communication with the first air inlet pipeline, and the second protective air duct (46) opens into the second light channel (441) to form a transverse air curtain.

4. The central wire feeding / powder feeding laser welding head with air knife protection according to claim 1, 2 or 3, characterized in that: The air knife assembly (4) also includes a welding material pipe limiting tube (47) and a protective nozzle (48); the laser convergence point (13) is located 20 to 30 mm below the protective nozzle (48); The welding material pipe limiting pipe (47) is installed at the lower end inside the second welding material channel (442), and the outlet of the welding material pipe limiting pipe (47) is flush with the outlet of the second welding material channel (442); The protection nozzle (48) is installed at the outlet of the second welding material channel (442); It also includes a welding material pipe (5) that passes through the first welding material channel (12), the middle welding material channel (342), the second welding material channel (442), the welding material pipe limiting pipe (47) and the protective nozzle (48) in sequence from top to bottom, and the lower end surface of the welding material pipe (5) is flush with the surface where the outlet of the protective nozzle (48) is located; the upper end of the welding material pipe (5) is installed on the top of the fixing seat (1) through a flange (52); The first welding material channel (12) comprises a first welding material channel upper section (121) and a first welding material channel lower section (122); the diameter of the first welding material channel upper section (121) is 0.5-1 mm smaller than the diameter of the first welding material channel lower section (122); the diameters of the intermediate welding material channel (342), the second welding material channel (442) and the first welding material channel lower section (122) are the same; the inner diameter of the welding material tube limiting tube (47) is the same as that of the first welding material channel upper section (121), and a plurality of third air passage grooves (471) evenly distributed around the circumference are provided on its outer wall; A gas passage is formed between the outer wall of the welding material pipe (5) and the lower section (122) of the first welding material passage, the middle welding material passage (342), the second welding material passage (442), the third gas passage groove (471), and the inner wall of the protective nozzle (48); A third protective gas channel (16) is arranged in the fixing seat (1) and is communicated with an external inert gas source and with the gas passage.

5. The central wire feeding / powder feeding laser welding head with air knife protection according to claim 4, characterized in that: The side of the fixing seat (1) is provided with a plurality of protective lens group mounting holes (14) for mounting the protective lens group (2); the protective lens group mounting holes (14) correspond one-to-one to the first optical channels (11); The protective mirror assembly (2) comprises a protective mirror (23) and a protective mirror seat (24), wherein the protective mirror seat (24) is slidably mounted in the protective mirror assembly mounting hole (14); A stepped light-transmitting hole is provided on the protective mirror seat (24), and the protective mirror (23) is mounted on the step of the stepped light-transmitting hole; A protective mirror sealing ring (22) is provided on the top of the protective mirror (23), the bottom of the protective mirror sealing ring (22) is in contact with the protective mirror (23), and the side of the protective mirror sealing ring (22) is in contact with the inner wall of the stepped light transmission hole; A handle (25) is provided on one side of the protective mirror seat (24). The handle (25) is fixedly mounted on the outer side wall of the fixing seat (1) by means of screws. A handle sealing ring (21) is provided between the side wall of the handle (25) and the fixing seat (1).

6. The central wire feeding / powder feeding laser welding head with air knife protection according to claim 5, characterized in that: The lower part of the wind knife assembly body (44) is sleeved with a window protection plate (6), a rubber pad (61) and a protection plate retaining ring (7) in sequence from top to bottom; The protection plate retaining ring (7) is threadedly connected to the air knife assembly body (44); The window protection plate (6) is provided with an arc-shaped limiting hole (63), and a third light channel (62) evenly distributed along the circumference of the axis of the window protection plate (6) and having the same number as the second light channel (441); The lower surface of the wind knife assembly body (44) is provided with a limiting boss (443) adapted to the arc-shaped limiting hole (63); when the window protection plate (6) rotates, the limiting boss (443) can slide in the arc-shaped limiting hole (63); When the limiting boss (443) is located at one end of the arc-shaped limiting hole (63), the third light channel (62) corresponds to the second light channel (441) one by one, and the axis of the third light channel (62) coincides with the axis of the corresponding second light channel (441); When the limiting boss (443) is located at the other end of the arc-shaped limiting hole (63), the third light channel (62) and the second light channel (441) are completely misaligned; The bottom of the air knife assembly body (44) is provided with a plurality of transverse air outlet grooves which are evenly distributed around the axis of the second welding material channel (442) and correspond to the position of the first protective air duct (45). The transverse air outlet grooves are connected to the first protective air duct (45), and the second protective air duct (46) is formed between the transverse air outlet grooves and the window protection plate (6).

7. The central wire feeding / powder feeding laser welding head with air knife protection according to claim 6, characterized in that: The first air inlet pipeline includes a fourth protective air duct (36) which is opened in the connection base body (34) and communicates with an external air source; A first annular groove is formed on the upper surface of the air knife assembly body (44) around the axis of the second welding material channel (442); a first annular groove and the lower surface of the connecting base body (34) form a first annular air duct (362); the first annular air duct (362) is communicated with the fourth protective air duct (36), the first air duct (361) and the first protective air duct (45); The second air inlet pipeline comprises a fifth protective air duct (17) which is opened in the fixing seat (1) and communicates with an external air source; A second annular groove is formed on the upper surface of the connecting base body (34) around the axis of the middle welding material channel (342); a second annular air duct (172) is formed between the second annular groove and the lower surface of the fixing seat (1); and the second annular air duct (172) is communicated with the fifth protective air duct (17) and the second air duct (171).

8. The central wire feeding / powder feeding laser welding head with air knife protection according to claim 7, characterized in that: A plurality of first water channels (15) connected to a circulating cooling water source are provided on the side of the fixing seat (1); A second water channel (49) is also provided on the side of the air knife assembly body (44); The second water channel (49) comprises a water channel (491) in an L-shaped structure and a water channel sealing plate (492) sleeved on the outside of the wind knife assembly body (44); the horizontal section of the water channel (491) is connected to the circulating cooling water source, and the vertical section passes through the bottom of the wind knife assembly body (44); The water channel sealing plate (492) is fixedly mounted on the bottom of the wind knife assembly body (44) by a plurality of screws, and an annular water groove (495) corresponding to the vertical section of the water channel (491) is provided on the water channel sealing plate (492); A third sealing ring (493) and a fourth sealing ring (494) are provided between the water channel sealing plate (492) and the wind knife assembly body (44); the inner diameter of the third sealing ring (493) is larger than the outer diameter of the annular water groove (495), and the outer diameter of the fourth sealing ring (494) is smaller than the inner diameter of the annular water groove (495).

9. A central wire feeding / powder feeding laser welding method with air knife protection, characterized in that: The steps include: S1. Prepare the central wire feeding / powder feeding laser welding head with air knife protection as described in any one of claims 1 to 8; S2. Connect the central wire feeding / powder feeding laser welding head with air knife protection to the welding equipment and complete the welding preparation work; S3, connecting the first air inlet pipeline to an external air source, so that the gas from the external air source enters the first air duct (361) through the first air inlet pipeline and forms a positive pressure environment at the lower end of the second light channel (441); S4, causing the plurality of laser beams (8) to be emitted along the plurality of optical channels respectively and to converge at the laser convergence point (13); S5, feeding the welding material (9) through the welding material channel to the laser convergence point (13) by means of a feeding device; S6. Adjusting the position of the laser welding head by means of welding equipment so that the laser convergence point (13) is located on the surface to be welded of the parent material (10) to be welded, and adjusting the gap between the parent materials (10) to be welded according to welding requirements; S7, the base material (10) to be welded and the welding material (9) absorb the energy of the laser beam (8), and are melted to form a molten pool and a liquid welding material respectively; S8. The laser welding head is moved by the welding equipment so that the laser convergence point (13) moves and leaves the liquid welding material, and the liquid welding material is rapidly cooled to form a welding seam, thereby completing the welding of the base material (10) to be welded.

10. The central wire feeding / powder feeding laser welding method with air knife protection according to claim 9, characterized in that: In step S2, the welding preparation work is completed as follows: S2.

1. Install multiple laser sources at the positions corresponding to each optical channel on the top of the fixing base (1); S2.2, rotating the window protection plate (6) to place the limiting boss (443) at one end of the arc-shaped limiting hole (63) so that the axis of the third light channel (62) coincides with the axis of the second light channel (441); S2.3, connecting the fifth protective air channel (17) to an external air source, and the external air source injects gas into the second annular air channel (172) and the second air channel (171) through the fifth protective air channel (17), so as to create a positive pressure environment at the lower end of the middle optical channel (341); S2.4, connecting the third protective gas channel (16) to an external inert gas source, the external inert gas source injects the inert gas into the gas passage through the third protective gas channel (16), and sprays the inert gas from between the protective nozzle (48) and the welding material pipe (5) to form an annular gas curtain; S2.5, connecting the circulating cooling water source to the first water channel (15) and the second water channel (49) respectively; Step S3 specifically comprises: connecting the fourth protective air duct (36) with an external air source, allowing the gas from the external air source to enter the first annular air duct (362) from the fourth protective air duct (36), and a portion of the gas is ejected from the first air duct (361) to the lower end of the second optical channel (441), thereby creating a positive pressure environment at the lower end of the second optical channel (441); another portion of the gas is ejected from the first protective air duct (45) and the second protective air duct (46) at the outlet of the second optical channel (441), thereby forming a transverse air curtain; Step S4 specifically includes causing the plurality of laser beams (8) to be emitted along the plurality of first optical channels (11), the middle optical channel (341), the second optical channel (441), and the third optical channel (62), respectively, and to converge at the laser convergence point (13); Step S5 specifically includes sending the welding material (9) from the welding material tube (5) to the laser convergence point (13) through a feeding device; In step S6, the thickness of the base material (10) to be welded is greater than 5 mm, and the gap is greater than 0.5 mm; In step S8, the moving speed of the welding equipment is greater than 1 m / min.

Images