Laser welding method for large-size ultrathin diaphragm assembly

Abstract

The invention discloses a laser welding method for a large-size ultrathin diaphragm assembly. The laser welding method comprises the steps that the butt joint portion of a diaphragm support and a diaphragm is cleaned; mounting the diaphragm bracket and the diaphragm on a welding positioning tool; the welding positioning tool is clamped to an external laser welding machine rotary table, a welding seam is aligned, laser positioning welding is conducted, and whole-circle positioning welding of the diaphragm support and the diaphragm is completed; and a positioning pressing plate in the welding positioning tool is replaced with a welding pressing plate, laser welding is conducted on the diaphragm and the diaphragm support, and the diaphragm assembly is obtained. By means of the method, efficient and high-quality welding of the large-size ultra-thin diaphragm can be achieved, the welding qualification rate of the diaphragm assembly is increased, the problems that when the large-size ultra-thin diaphragm is welded at present, weld gaps, weld beading, weld joint sinking, wave weld joints and the like are prone to occurring are effectively solved, and the purpose that the product qualification rate is increased to 95% from 30% is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of welding, and in particular relates to a laser welding method for a large-size ultra-thin film assembly. Background Art

[0002] The diaphragm assembly is welded by the diaphragm and the diaphragm bracket. It is widely used in aerospace liquid rocket engine systems to seal and isolate the propellant in the tank. There are 325° circumferential notches on the diaphragm. When the system is working, the tank piston needs to successfully break through the diaphragm notch position, and the propellant flows from the upstream of the system to the downstream. For long-term storage of liquid rocket engines, the welding reliability of the diaphragm assembly is particularly critical.

[0003] The diaphragm must not only match the size of the tank interface but also ensure smooth cutting. Therefore, the diaphragm is generally large and thin. For two butt-jointed products with large differences in wall thickness, the gap between the diaphragm and the diaphragm bracket before welding is too large, resulting in uneven heat dissipation. The welding process is prone to poor forming defects such as weld gaps, weld bumps, weld depressions, and wavy welds, which lead to sealing failure of the diaphragm assembly and reduced cutting mechanical properties. Existing welding tools and process solutions are only suitable for small and thick diaphragms. There are no mature welding tools and process solutions for large-sized thin films, and the welding qualification rate cannot be well guaranteed. Summary of the invention

[0004] The technology of the present invention solves the problem: Overcoming the shortcomings of the prior art, providing a laser welding method for large-size ultra-thin film assemblies, which can achieve efficient and high-quality welding of large-size ultra-thin films, improve the welding qualification rate of diaphragm assemblies, and effectively improve the current problems of weld gaps, weld nodules, weld depressions and wavy welds that are prone to occur during welding of large-size ultra-thin films, thereby achieving the purpose of increasing the product qualification rate from 30% to 95%.

[0005] In order to solve the above technical problems, the present invention discloses a laser welding method for a large-size ultra-thin film assembly, comprising:

[0006] Clean the joint between the diaphragm bracket and the diaphragm;

[0007] Install the diaphragm bracket and diaphragm on the welding positioning fixture;

[0008] Clamp the welding positioning tooling onto the external laser welding machine turntable, align the weld, perform laser positioning welding, and complete the full-circle positioning welding of the diaphragm bracket and the diaphragm;

[0009] The positioning pressure plate in the welding positioning tool is replaced with a welding pressure plate, and the diaphragm and the diaphragm bracket are laser welded to obtain a diaphragm assembly.

[0010] In the above-mentioned laser welding method for large-size ultra-thin film components, the welding positioning tooling includes: a lower base plate, a support plate, a positioning pressure plate, a pressure block, bolts and butterfly nuts; wherein the diaphragm bracket and the diaphragm are installed on the welding positioning tooling, including:

[0011] Put the diaphragm bracket on the inner wall of the lower bottom plate to ensure that the outer wall of the diaphragm bracket fits tightly with the inner wall of the lower bottom plate;

[0012] Put the support plate into the guide groove of the lower base plate;

[0013] Assemble the diaphragm to the diaphragm bracket, and adjust the fitting clearance between the diaphragm and the diaphragm bracket to ensure that the fitting clearance is uniform in the circumferential direction;

[0014] Press the positioning plate onto the diaphragm;

[0015] Press the pressure block onto the positioning pressure plate and tighten it with bolts and butterfly nuts to ensure that the diaphragm and the diaphragm bracket fit tightly around the entire circumference.

[0016] In the above-mentioned laser welding method for large-size ultra-thin film components, a fixed shaft, a gas supply channel, two exhaust holes, a guide groove and two lower bottom plate flange holes are provided on the lower bottom plate; wherein, the fixed shaft is arranged at the center of the lower bottom plate, and the interior of the fixed shaft is hollow to form a gas supply channel; the fixed shaft is used to clamp the welding positioning tooling to the external laser welding machine turntable; the gas supply channel is used to transport the back protective gas to the air flow channel of the support plate; the two exhaust holes and the two lower bottom plate flange holes are symmetrically arranged on the lower bottom plate, and the lower bottom plate flange holes are located outside the exhaust holes; the exhaust holes are used to discharge the back protective gas; the lower bottom plate flange holes are used to achieve the fastening of the lower bottom plate and the pressing block through bolts and butterfly nuts, thereby ensuring that the diaphragm and the diaphragm bracket are tightly fitted around the entire circumference; the guide groove is arranged above the fixed shaft and is connected to the gas supply channel; the guide groove cooperates with the positioning core shaft of the support plate to realize the coaxial installation of the support plate and the lower bottom plate, thereby ensuring uniform heat dissipation and uniform airflow protection during welding.

[0017] In the above-mentioned laser welding method for large-size ultra-thin film components, a positioning core shaft and six air flow channels are arranged on the support plate; wherein, the positioning core shaft is arranged in the center of the support plate, and the positioning core shaft cooperates with the guide groove to realize the coaxial installation of the support plate and the lower base plate, thereby ensuring uniform heat dissipation and airflow protection during welding; the six air flow channels are evenly distributed circumferentially on the support plate, for homogenizing the back protective gas, and evenly distributing the back protective gas on the diaphragm bracket and the diaphragm.

[0018] In the above-mentioned laser welding method for large-size ultra-thin film components, a plurality of positioning semicircular grooves are evenly arranged around the outer diameter of the positioning pressure plate; wherein the positioning semicircular grooves are used to reserve space for positioning welding between the diaphragm bracket and the diaphragm.

[0019] In the above-mentioned laser welding method for large-size ultra-thin film components, when the positioning plate is pressed onto the diaphragm, the positioning plate is ensured to be concentric with the diaphragm, that is, the weld position of the diaphragm is exposed in the positioning semicircular groove.

[0020] In the above-mentioned laser welding method for large-size ultra-thin film assemblies, a pressing block flange hole is provided at each end of the pressing block; wherein the pressing block flange hole matches the position of the flange hole of the lower base plate, and the lower base plate and the pressing block are fastened by bolts and butterfly nuts, thereby ensuring that the diaphragm and the diaphragm bracket are tightly fitted around the entire circumference.

[0021] In the above-mentioned laser welding method for large-size ultra-thin film components, the outer diameter of the welding pressure plate is smaller than the outer diameter of the positioning pressure plate.

[0022] In the above-mentioned laser welding method for large-size ultra-thin film components, cleaning the butt joint between the diaphragm support and the diaphragm includes:

[0023] Degreasing and pickling the surface of the diaphragm bracket to remove surface oil and oxides;

[0024] Use alcohol to clean the diaphragm surface to remove pollutants on the diaphragm surface.

[0025] In the above-mentioned laser welding method for large-size ultra-thin film components,

[0026] Laser positioning welding parameters are as follows:

[0027] The angle between the front shielding gas nozzle and the weld is 30° to 40°;

[0028] The vertical distance between the front protection gas nozzle and the weld is 1mm to 3mm;

[0029] The front shielding gas flow rate is 20L / min~30L / min;

[0030] The back shielding gas enters the air flow channel through the gas delivery channel and then flows into the back of the weld;

[0031] Laser power is 210W~240W;

[0032] The positioning welding points are arranged circumferentially, the number is 100, and the welding time of each positioning welding point is 0.1s to 0.3s;

[0033] Laser welding parameters are as follows:

[0034] The angle between the front shielding gas nozzle and the weld is 30° to 40°;

[0035] The vertical distance between the front protection gas nozzle and the weld is 1mm to 3mm;

[0036] The front shielding gas flow rate is 20L / min~30L / min;

[0037] The back shielding gas enters the air flow channel through the gas delivery channel and then flows into the back of the weld;

[0038] The laser power is 260W~300W, and the welding speed is 250mm / min~300mm / min.

[0039] The present invention has the following advantages:

[0040] (1) The present invention discloses a laser welding method for a large-sized ultra-thin film assembly. By using a welding positioning tool, reliable positioning welding of the large-sized diaphragm is ensured, the heat dissipation conditions during the welding process of the large-sized ultra-thin film assembly are improved, and through appropriate welding parameters, defects such as weld gaps, weld nodules, weld depressions and wavy welds are effectively avoided, and the welding qualification rate is increased to more than 95%.

[0041] (2) The present invention discloses a laser welding method for a large-size ultra-thin film assembly. By adding multiple protective gases, sufficient argon protection is achieved on the back and front of the diaphragm assembly, effectively solving the existing problem of back-side oxidation of the diaphragm.

[0042] (3) The present invention discloses a laser welding method for a large-size ultra-thin film assembly. The welding positioning tooling used has a simple structure, is easy to assemble, and has good process stability, and is suitable for mass production of the same type of diaphragm assemblies. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a cross-sectional view of a welding positioning tool in an embodiment of the present invention;

[0044] Figure 2 is a top view of a welding positioning tool in an embodiment of the present invention;

[0045] Figure 3 is a top view of a diaphragm assembly in an embodiment of the present invention;

[0046] Figure 4 is a front view of a diaphragm assembly in an embodiment of the present invention;

[0047] Figure 5 is a schematic structural diagram of a diaphragm in an embodiment of the present invention;

[0048] Figure 6 is a cross-sectional view of a lower base plate in an embodiment of the present invention;

[0049] Figure 7 is a top view of a support plate in an embodiment of the present invention;

[0050] Figure 8 is a side view of a support plate in an embodiment of the present invention;

[0051] Fig. 9 A top view of a positioning plate in an embodiment of the present invention

[0052] Fig.10 is a front view of a positioning plate in an embodiment of the present invention;

[0053] Fig.11 It is a structural schematic diagram of a welding pressure plate in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0055] In this embodiment, the laser welding method of the large-size ultra-thin film assembly includes:

[0056] Step 1: Clean the joint between the diaphragm support 1 and the diaphragm 2.

[0057] In this embodiment, the joint between the diaphragm bracket 1 and the diaphragm 2 can be cleaned in the following manner: the surface of the diaphragm bracket 1 is degreased and pickled to remove surface oil and oxides; the surface of the diaphragm 2 is cleaned with alcohol to remove pollutants on the surface of the diaphragm 2.

[0058] Preferably, Figures 3 to 5 As shown, the diaphragm bracket 1 is made of TC4, and has a groove on the surface for placing the diaphragm 2. The groove depth is 0.23mm to 0.27mm, and the radial dimension of the groove is 110mm. The diaphragm 2 is made of TAD, with a thickness of 0.11mm to 0.12mm, and an outer diameter of 110mm. There is a 325° circumferential notch on the diaphragm 2, and the radial position of the notch is Φ97mm. The fitting clearance between the diaphragm 2 and the diaphragm bracket 1 is 0.02mm to 0.05mm, and the fitting clearance is controlled by the outer diameter of the diaphragm 2 and the size tolerance of the groove of the diaphragm bracket 1.

[0059] Step 2: Install the diaphragm bracket 1 and the diaphragm 2 on the welding positioning tool.

[0060] In this embodiment, if Figures 1-2As shown, the welding positioning fixture includes: a lower bottom plate 3, a support plate 4, a positioning pressure plate 5, a pressure block 6, a bolt 7 and a butterfly nut 8. The diaphragm bracket 1 and the diaphragm 2 are installed on the welding positioning fixture in the following manner: the diaphragm bracket 1 is mounted on the inner wall of the lower bottom plate 3 to ensure that the outer wall of the diaphragm bracket 1 is tightly fitted with the inner wall of the lower bottom plate 3; the support plate 4 is mounted in the guide groove 304 of the lower bottom plate 3; the diaphragm 2 is assembled to the diaphragm bracket 1, and the matching clearance between the diaphragm 2 and the diaphragm bracket 1 is adjusted to ensure that the matching clearance is uniform in the circumferential direction; the positioning pressure plate 5 is pressed onto the diaphragm 2; the pressure block 6 is pressed onto the positioning pressure plate 5, and is tightened by the bolts 7 and the butterfly nut 8 to ensure that the diaphragm 2 is tightly fitted with the diaphragm bracket 1 throughout the entire circumference.

[0061] Preferably, Figure 6 As shown, the lower bottom plate 3 is provided with a fixed shaft 301, a gas transmission channel 302, two exhaust holes 303, a guide groove 304 and two lower bottom plate flange holes 305. Among them, the fixed shaft 301 is arranged at the center of the lower bottom plate 3, and the interior of the fixed shaft 301 is hollow to form a gas transmission channel 302; the fixed shaft 301 is used to clamp the welding positioning tooling to the external laser welding machine turntable; the gas transmission channel 302 is used to transport the back protective gas to the air flow channel 402 of the support plate 4. The two exhaust holes 303 and the two lower bottom plate flange holes 305 are symmetrically arranged on the lower bottom plate 3, and the lower bottom plate flange holes 305 are located outside the exhaust holes 303; the exhaust holes 303 are used to discharge the back protective gas; the lower bottom plate flange holes 305 are used to realize the fastening of the lower bottom plate 3 and the pressing block 6 through bolts 7 and butterfly nuts 8, thereby ensuring that the diaphragm 2 and the diaphragm bracket 1 are tightly fitted all around. The guide groove 304 is arranged above the fixed shaft 301 and communicates with the gas delivery channel 302; the guide groove 304 cooperates with the positioning mandrel 401 of the support plate 4 to realize the coaxial installation of the support plate 4 and the lower base plate 3, ensuring uniform heat dissipation and airflow protection during welding. Furthermore, the exhaust hole 303 is 45 mm away from the center of the lower base plate 3, and the diameter of the guide groove 304 is 30 mm to 40 mm.

[0062] Preferably, Figures 7-8As shown, the support plate 4 is provided with a positioning mandrel 401 and six air flow channels 402. Among them, the positioning mandrel 401 is arranged at the center of the support plate 4, and the positioning mandrel 401 cooperates with the guide groove 304 to realize the coaxial installation of the support plate 4 and the lower bottom plate 3, so as to ensure uniform heat dissipation and air flow protection during welding. The six air flow channels 402 are evenly distributed on the support plate 4 in the circumferential direction, and are used to homogenize the back protective gas and evenly distribute the back protective gas on the diaphragm bracket 1 and the diaphragm 2. That is, the first function of the support plate 4 is to support the diaphragm 2 to prevent the diaphragm 2 from deforming after the positioning pressing plate 5 presses the diaphragm 2; the second function is to coaxially arrange the support plate 4 and the lower bottom plate 3 to ensure uniform heat dissipation during the welding process of the diaphragm 2; the third function is to provide a transportation channel for the back protective gas of the weld to ensure that the back of the weld is not oxidized. Further, the outer diameter of the support plate 4 is 3mm to 5mm smaller than the outer diameter of the diaphragm 2; the diameter of the positioning mandrel 401 is 30mm to 40mm.

[0063] Preferably, Figures 9-10 As shown, the outer diameter of the positioning platen 5 is evenly provided with a plurality of positioning semicircular grooves 501. Among them, the positioning semicircular grooves 501 are used to reserve space for the positioning welding of the diaphragm bracket 1 and the diaphragm 2. When the positioning platen 5 is pressed onto the diaphragm 2, it is ensured that the positioning platen 5 is concentric with the diaphragm 2, that is, the weld position of the diaphragm 2 is exposed in the positioning semicircular grooves 501. Furthermore, the outer diameter of the positioning platen 5 is 109.7mm to 109.8mm, which ensures that the edge of the diaphragm 2 is completely compacted; the outer diameter of the positioning platen 5 is evenly provided with 50 positioning semicircular grooves 501, and the diameter of the positioning semicircular grooves 501 is 5mm, which ensures that the edge of the diaphragm 2 is completely compacted.

[0064] Preferably, a pressing block flange hole is provided at each end of the pressing block 6; wherein the pressing block flange hole matches the position of the lower base plate flange hole 305, and the lower base plate 3 and the pressing block 6 are fastened by bolts 7 and butterfly nuts 8, thereby ensuring that the diaphragm 2 and the diaphragm bracket 1 are tightly fitted around the entire circumference.

[0065] Preferably, Fig.11 As shown, the outer diameter of the welding pressing plate 9 is 106 mm, which is smaller than the outer diameter of the positioning pressing plate 5 .

[0066] It should be noted that the materials of the support plate 4, the positioning plate 5, the pressing block 6 and the welding plate 9 are all brass. The surfaces of the support plate 4 and the positioning plate 5 in contact with the diaphragm 2 must be smooth and free of any surface defects. Before installing the diaphragm bracket 1 and the diaphragm 2 on the welding positioning fixture, the welding positioning fixture must be cleaned: use alcohol to clean the contact surfaces of the bottom plate 3, the support plate 4 and the positioning plate 5 with the diaphragm bracket 1 and the diaphragm 2.

[0067] Step 3, clamp the welding positioning tool onto the turntable of the external laser welding machine, align the weld, perform laser positioning welding, and complete the full-circle positioning welding of the diaphragm bracket 1 and the diaphragm 2.

[0068] In this embodiment, during the laser positioning welding process, the shielding portion of the positioning pressure plate 5 can be adjusted by rotating the diaphragm bracket 1 and the diaphragm 2, thereby completing the whole-circle positioning welding.

[0069] Preferably, the laser positioning welding parameters are as follows:

[0070] The angle between the front shielding gas nozzle and the weld is 30° to 40°;

[0071] The vertical distance between the front protection gas nozzle and the weld is 1mm to 3mm;

[0072] The front shielding gas flow rate is 20L / min~30L / min;

[0073] The back shielding gas enters the gas flow channel 402 through the gas delivery channel 302 and then flows into the back of the weld;

[0074] Laser power is 210W~240W;

[0075] The positioning welding spots are arranged circumferentially, with a number of 100 (ie, 50 positioning semicircular grooves are evenly arranged around the outer diameter of the positioning pressure plate, and 2 positioning welding spots are arranged in each positioning semicircular groove), and the welding time of each positioning welding spot is 0.1s to 0.3s.

[0076] Step 4: Replace the positioning platen 5 in the welding positioning tool with the welding platen 9, and perform laser welding on the diaphragm 2 and the diaphragm bracket 1 to obtain a diaphragm assembly.

[0077] In this embodiment, the laser welding parameters are as follows:

[0078] The angle between the front shielding gas nozzle and the weld is 30° to 40°;

[0079] The vertical distance between the front protection gas nozzle and the weld is 1mm to 3mm;

[0080] The front shielding gas flow rate is 20L / min~30L / min;

[0081] The back shielding gas enters the gas flow channel 402 through the gas delivery channel 302 and then flows into the back of the weld;

[0082] The laser power is 260W~300W, and the welding speed is 250mm / min~300mm / min.

[0083] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0084] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. A laser welding method for large-size ultra-thin film components, characterized in that: include: Cleaning the joint between the diaphragm support (1) and the diaphragm (2); Installing the diaphragm bracket (1) and the diaphragm (2) on the welding positioning tool; Clamp the welding positioning tool onto the external laser welding machine turntable, align the weld seam, perform laser positioning welding, and complete the full-circle positioning welding of the diaphragm bracket (1) and the diaphragm (2); The positioning pressure plate (5) in the welding positioning tool is replaced with a welding pressure plate (9), and the diaphragm (2) and the diaphragm bracket (1) are laser welded to obtain a diaphragm assembly.

2. The laser welding method for large-size ultra-thin film components according to claim 1 is characterized in that: The welding positioning tool comprises: a lower base plate (3), a support plate (4), a positioning pressure plate (5), a pressure block (6), a bolt (7) and a butterfly nut (8); wherein the diaphragm bracket (1) and the diaphragm (2) are mounted on the welding positioning tool, comprising: The diaphragm support (1) is mounted on the inner wall of the lower base plate (3) to ensure that the outer wall of the diaphragm support (1) is tightly fitted to the inner wall of the lower base plate (3); Insert the support plate (4) into the guide groove (304) of the lower base plate (3); Assemble the diaphragm (2) to the diaphragm support (1), and adjust the matching clearance between the diaphragm (2) and the diaphragm support (1) to ensure that the matching clearance is uniform in the circumferential direction; Pressing the positioning plate (5) onto the diaphragm (2); The pressure block (6) is pressed onto the positioning pressure plate (5), and is tightened by means of bolts (7) and butterfly nuts (8) to ensure that the diaphragm (2) and the diaphragm support (1) are tightly fitted around the entire circumference.

3. The laser welding method for large-size ultra-thin film components according to claim 2 is characterized in that: The lower bottom plate (3) is provided with a fixed shaft (301), a gas transmission channel (302), two exhaust holes (303), a guide groove (304) and two lower bottom plate flange holes (305); wherein the fixed shaft (301) is arranged at the center of the lower bottom plate (3), and the interior of the fixed shaft (301) is hollow to form a gas transmission channel (302); the fixed shaft (301) is used to clamp the welding positioning tooling onto the external laser welding machine turntable; the gas transmission channel (302) is used to transport the back protective gas to the air flow channel (402) of the support plate (4); the two exhaust holes (303) and the two lower bottom plate flange holes (305) are symmetrically arranged on the lower bottom plate (3) respectively. The flange hole (305) of the lower bottom plate is located outside the exhaust hole (303); the exhaust hole (303) is used to discharge the back protective gas; the flange hole (305) of the lower bottom plate is used to fasten the lower bottom plate (3) and the pressing block (6) through bolts (7) and butterfly nuts (8), thereby ensuring that the diaphragm (2) and the diaphragm bracket (1) are tightly fitted around the entire circumference; the guide groove (304) is arranged above the fixed shaft (301) and is connected to the gas transmission channel (302); the guide groove (304) cooperates with the positioning core shaft (401) of the support plate (4) to achieve coaxial installation of the support plate (4) and the lower bottom plate (3), thereby ensuring uniform heat dissipation and uniform airflow protection during welding.

4. The laser welding method for large-size ultra-thin film components according to claim 3 is characterized in that: A positioning mandrel (401) and six air flow channels (402) are provided on the support plate (4); wherein the positioning mandrel (401) is arranged at the center of the support plate (4), and the positioning mandrel (401) cooperates with the guide groove (304) to realize coaxial installation of the support plate (4) and the lower base plate (3), thereby ensuring uniform heat dissipation and air flow protection during welding; the six air flow channels (402) are evenly distributed on the support plate (4) in a circumferential direction, and are used to evenly distribute the back protective gas, so as to evenly distribute the back protective gas on the diaphragm bracket (1) and the diaphragm (2).

5. The laser welding method for large-size ultra-thin film components according to claim 2 is characterized in that: A plurality of positioning semicircular grooves (501) are evenly arranged around the outer diameter of the positioning pressure plate (5); wherein the positioning semicircular grooves (501) are used to reserve space for positioning welding between the diaphragm bracket (1) and the diaphragm (2).

6. The laser welding method for large-size ultra-thin film components according to claim 5 is characterized in that: When the positioning pressing plate (5) is pressed onto the diaphragm (2), it is ensured that the positioning pressing plate (5) and the diaphragm (2) are concentric, that is, the welding seam position of the diaphragm (2) is exposed in the positioning semicircular groove (501).

7. The laser welding method for large-size ultra-thin film components according to claim 3 is characterized in that: A pressing block flange hole is provided at each end of the pressing block (6); wherein the pressing block flange hole matches the position of the lower base plate flange hole (305), and the lower base plate (3) and the pressing block (6) are fastened by bolts (7) and butterfly nuts (8), thereby ensuring that the diaphragm (2) and the diaphragm bracket (1) are tightly fitted around the entire circumference.

8. The laser welding method for large-size ultra-thin film components according to claim 1 is characterized in that: The outer diameter of the welding pressing plate (9) is smaller than the outer diameter of the positioning pressing plate (5).

9. The laser welding method for large-size ultra-thin film components according to claim 1 is characterized in that: Cleaning the joint between the diaphragm support (1) and the diaphragm (2), including: Degreasing and pickling the surface of the diaphragm bracket (1) to remove surface oil stains and oxides; The surface of the diaphragm (2) is cleaned with alcohol to remove pollutants on the surface of the diaphragm (2).

10. The laser welding method for large-size ultra-thin film components according to claim 1, characterized in that: Laser positioning welding parameters are as follows: The angle between the front shielding gas nozzle and the weld is 30° to 40°; The vertical distance between the front protection gas nozzle and the weld is 1mm to 3mm; The front shielding gas flow rate is 20L / min~30L / min; The back side shielding gas enters the gas flow channel (402) through the gas delivery channel (302) and then flows into the back side of the weld; Laser power is 210W~240W; The positioning welding points are arranged circumferentially, the number is 100, and the welding time of each positioning welding point is 0.1s to 0.3s; Laser welding parameters are as follows: The angle between the front shielding gas nozzle and the weld is 30° to 40°; The vertical distance between the front protection gas nozzle and the weld is 1mm to 3mm; The front shielding gas flow rate is 20L / min~30L / min; The back side shielding gas enters the gas flow channel (402) through the gas delivery channel (302) and then flows into the back side of the weld; The laser power is 260W~300W, and the welding speed is 250mm / min~300mm / min.

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