Roll-welding forming method of multi-cavity profile

Abstract

The application provides a roll welding forming method of a multi-cavity profile, comprising the following steps: in the process of roll bending a plate to form a first cavity, reversely roll bending the plate in a region corresponding to a welding position of the first cavity to make the plate in the region give way and form an incident angle space for a first weld laser; using a laser welding device, the first weld laser is shot into the welding position through the incident angle space to perform first angle welding; after the angle welding is completed, the reversely roll bent plate is rolled to restore the shape before the reverse roll bending, and then the plate is continuously roll bent to form a remaining cavity structure. The plate in a non-forming region is reversely bent by a certain angle in advance to open an incident angle space of a first weld laser, and first welding forming angle welding is realized, which improves the welding speed and ensures more stable and efficient welding quality.

Description

Technical Field

[0001] This invention relates to the field of roll forming technology, and more specifically, to a roll forming and welding method for multi-cavity profiles. Background Technology

[0002] like Figure 1 As shown, when performing roll forming welding on multi-cavity profiles, due to the traditional mold design, the right-side sheet material is first partially formed into a pre-defined structure. When welding is performed after the first cavity structure on the left side is formed, the incident angle parallel to the welding fusion area is blocked by the already formed sheet material on the right side. This means that when performing laser welding on the welding fusion area, the laser incident direction can only be from top to bottom or at an angle of less than 45°. In other words, the two layers of sheet material are connected by lap welding. The welding depth and effective connection width are affected by the process conditions, the adjustable process window is small, the range of welding speed adjustment is limited, and welding defects such as incomplete welds and burn-through are easily generated, affecting product quality.

[0003] Patent document CN110038963B discloses a method for forming a H-shaped tube and a forming mold, including steps S1: bending the two ends of a sheet metal at 90° in opposite directions; S2: bending the sheet metal vertically upward, horizontally, and vertically downward sequentially from the bending starting point according to the mold shape, with the bent end of the sheet metal contacting the upper surface of the unbent sheet metal, wherein the vertical downward bending of the sheet metal forms an inner rib; S3: welding the bent end of the sheet metal to the upper surface of the contacting unbent sheet metal; S4: placing the mold on the unbent sheet metal with the mold tightly against the inner rib, bending the sheet metal vertically upward and horizontally sequentially according to the mold shape, with the bent end of the sheet metal contacting the inner rib; S5: adjusting the position of the sheet metal, welding the bent end of the sheet metal to the inner rib to form a H-shaped tube; S6: removing the mold. However, this patent document still uses lap welding, which still easily leads to welding defects such as incomplete welds and weld burn-through. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a roll forming method for multi-cavity profiles.

[0005] A roll forming method for multi-cavity profiles according to the present invention includes the following steps:

[0006] During the process of roll bending the sheet metal to form the first cavity, the sheet metal in the area corresponding to the welding position of the first cavity is subjected to reverse roll bending, so that the sheet metal in the area makes room to form an incident angle space for the laser to penetrate the first weld.

[0007] Using laser welding equipment, the first weld laser is injected into the welding position through the incident angle space to perform the first corner weld.

[0008] After the corner welding is completed, the sheet material that has been reverse-bent is rolled to restore its shape before the reverse-bent bending. Then the sheet material is rolled to form the remaining cavity structure.

[0009] Preferably, the multi-cavity profile is a Z-shaped tube profile;

[0010] After the corner welding is completed, the sheet material that has been reverse rolled is rolled to restore its shape before the reverse roll bending. Then the sheet material is rolled and bent to form the second cavity.

[0011] A second weld laser is applied to the welding position of the second cavity to perform a second corner weld.

[0012] Preferably, the roll forming method specifically includes the following steps:

[0013] Step S1: Roll bend one end of the sheet towards the center of the sheet to form the first bend structure;

[0014] Step S2: Roll bend the sheet material towards the center at a predetermined distance from the first bend structure to form the second bend structure;

[0015] Step S3: Perform reverse roll bending on the non-forming area of ​​the sheet material at a preset length from the second bend structure, in the opposite direction to steps S1 and S2, to form the third bend structure;

[0016] Step S4: Roll bend the other end of the sheet towards the center of the sheet to form the seventh bend structure;

[0017] Step S5: Roller bend the sheet material towards the center at a predetermined distance from the seventh bend structure to form the sixth bend structure;

[0018] Step S6: Roller bend the sheet material towards the center at a predetermined distance from the sixth bend structure to form the fifth bend structure;

[0019] Step S7: Roll bend the sheet metal towards the center at a predetermined distance from the fifth bend structure to form the fourth bend structure, so that the seventh bend structure abuts against the end of the third bend structure away from the second bend structure, forming the first welding position and the first cavity; the clearance area formed by the reverse roll bend of the third bend structure forms the incident angle space for the first weld laser to be injected into the first welding position;

[0020] Step S8: Using laser welding equipment, the first weld laser is injected into the first welding position through the incident angle space to perform the first corner weld;

[0021] Step S9: Roll bend the third corner structure toward the center of the sheet metal to adjust the third corner structure into a flat wall structure;

[0022] Step S10: Perform a second roll bending on the second bend structure towards the center of the sheet metal, and adjust the angle value of the second bend structure;

[0023] Step S11: Roller bend the flat wall structure towards the center of the sheet at a predetermined distance from the second bend structure to form the eighth bend structure, so that the first bend structure abuts against the sixth bend structure to form the second welding position and the second cavity;

[0024] Step S12: Using laser welding equipment, a second weld laser is applied to the second welding position to perform a second corner weld.

[0025] Preferably, in the first corner weld, the welding focal length is controlled at 200-350mm, the welding speed is about 1-20m / min, and the welding power is controlled at 1000-8000w.

[0026] Preferably, in the first fillet weld, a side-blown welding shielding gas is used.

[0027] Preferably, in the first corner weld, the laser is injected parallel into the welding area to fuse the two layers of sheet metal together in the form of laser corner weld.

[0028] Preferably, in the first fillet weld, the effective connection length of the two plates connected by the weld is 0δ to 2δ, where δ is the thickness of the plate, and the angle between the extension direction of the weld and the extension direction of the plate connection is α, where α ranges from 0° to 45°.

[0029] Preferably, in the second corner weld, the welding focal length is controlled at 200-350mm, the welding speed is about 1-20m / min, and the welding power is controlled at 1000-8000w;

[0030] In the second fillet weld, a side-blown welding shielding gas is used;

[0031] In the second corner weld, the laser is injected into the welding area in parallel, and the two layers of sheet metal are fused together by laser corner welding.

[0032] In the second fillet weld, the effective connection length of the two plates connected by the weld is 0δ~2δ, where δ is the thickness of the plate, and the angle between the extension direction of the weld and the extension direction of the plate connection is α, where α ranges from 0° to 45°.

[0033] Preferably, in step S1, the first bend structure is a right-angle structure, forming a first welded connection structure;

[0034] In step S2, the second bend structure is an obtuse angle structure, and a first top wall is formed between the first bend structure and the second bend structure.

[0035] In step S3, the third bend structure is an arc-shaped bend structure;

[0036] In step S4, the seventh bend structure is a right-angle structure, forming the second welded connection structure;

[0037] In step S5, the sixth bend structure is a right-angle structure, and a first support wall is formed between the seventh bend structure and the sixth bend structure.

[0038] In step S6, the fifth bend structure is a right-angle structure, and a second top wall is formed between the sixth bend structure and the fifth bend structure;

[0039] In step S7, the fourth bend structure is a right-angle structure, a second support wall is formed between the fifth bend structure and the fourth bend structure, and a first bottom wall is formed between the four bend structures and the seventh bend structure.

[0040] In step S9, the flat wall structure is connected to the first bottom wall and is parallel to the first bottom wall;

[0041] In step S10, the second bend structure is a right-angle structure;

[0042] In step S11, the eighth bend structure is a right-angle structure, and a third support wall is formed between the eighth bend structure and the second bend structure; a second bottom wall is formed between the eighth bend structure and the seventh bend structure.

[0043] Preferably, in step S8, the sixth bend structure, the two side structures of the sixth bend structure, and the seventh bend structure are fixed by the first auxiliary roller, the fifth bend structure and the two side structures of the fifth bend structure are fixed by the second auxiliary roller, and the second bend structure, the two side structures of the second bend structure, the third bend structure, and the two side structures of the third bend structure are supported by the lower roller.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1. This invention reverses the non-formed area to open up the laser incident angle space of the first weld seam, thereby achieving the first weld forming fillet weld. The first weld fillet weld method greatly improves the effective connection length of the weld seam, enhances the stability of the welding process, and ensures the strength and quality of the weld seam.

[0046] 2. This invention involves bending the sheet material in the reverse direction in the non-formed area so that the connection direction of the sheet material in the section to be welded is parallel to the incident direction of the laser, thereby realizing laser fillet welding, increasing the effective connection length of the product weld, and thus improving the strength of the weld.

[0047] 3. The method of the present invention adopts a reverse bending design for the non-formed area, breaking through the traditional design concept of not forming the non-formed area but only forming the corresponding bending R-angle. The innovative method opens the right side shielding area, so that the welding incident direction of the first weld seam to be welded is parallel to the incident angle of the laser head, thus achieving more stable laser corner welding. Attached Figure Description

[0048] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0049] Figure 1 This is a schematic diagram of the existing roll forming welding method;

[0050] Figure 2 This is a flowchart illustrating the steps of the roll forming method for multi-cavity profiles according to the present invention. Figure 1 ;

[0051] Figure 3 This is a flowchart illustrating the steps of the roll forming method for multi-cavity profiles according to the present invention. Figure 2 ;

[0052] Figure 4 This is a schematic diagram of the structure of the step-by-step roll forming method of the present invention.

[0053] Figure 5 The structural diagram is shown to highlight the third bend structure and the welding process;

[0054] Figure 6 To highlight the structural diagram showing the incident angle space formed by the third bend structure;

[0055] Figure 7 A schematic diagram to highlight the incident direction of laser welding;

[0056] Figure 8 This is a schematic diagram of the structure of a multi-cavity profile prepared by roll forming and welding.

[0057] The diagram shows:

[0058] First bend structure 1; Third support wall 13

[0059] Second bend structure 2 First bottom wall 14

[0060] Third bend structure 3 Second bottom wall 15

[0061] Fourth bend structure 4 First cavity 16

[0062] Fifth bend structure 5 Second cavity 17

[0063] The sixth bend angle structure 6, incident angle space 18

[0064] Seventh bend structure 7 First welding position 19

[0065] Eighth bend structure 8, second welding position 20

[0066] First top wall 9 First auxiliary roller 21

[0067] Second top wall 10 Second auxiliary roller 22

[0068] First support wall 11, lower roller 23

[0069] Second support wall 12 Laser welding equipment 24 Detailed Implementation

[0070] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0071] Example 1:

[0072] like Figure 1-8 As shown, this embodiment provides a roll forming method for multi-cavity profiles, including the following steps: during the roll bending process of sheet metal to form the first cavity 16, the sheet metal in the area corresponding to the welding position of the first cavity 16 is subjected to reverse roll bending, so that the sheet metal in the area makes room to form an incident angle space 18 for the first weld laser to be injected; using a laser welding device 24, the first weld laser is injected into the welding position through the incident angle space 18 to perform the first corner weld; after the corner weld is completed, the reverse roll bent sheet metal is rolled to restore its shape before the reverse roll bending, and then the sheet metal is rolled and bent again to form the remaining cavity structure.

[0073] In the first fillet weld, the welding focal length is controlled at 200-350mm, the welding speed at approximately 1-20m / min, and the welding power at 1000-8000W. Side-blown welding shielding gas is used in the first fillet weld. The laser is injected parallel into the welding area to fuse the two sheet metal layers together using laser fillet welding. In the first fillet weld, the effective connection length of the two sheet metal layers through the weld is 0δ~2δ, where δ is the sheet metal thickness, and the angle between the weld extension direction and the extension direction at the joint is α, ranging from 0° to 45°.

[0074] The multi-cavity profile is a H-shaped tube profile; after the corner welding is completed, the sheet material that has been reverse rolled is rolled to restore its shape before the reverse roll bending, and then the sheet material is rolled and bent to form the second cavity 17; a second weld laser is applied to the welding position of the second cavity 17 to perform the second corner welding.

[0075] The welding focal length is controlled at 200-350mm, the welding speed is about 1-20m / min, and the welding power is controlled at 1000-8000w; in the second corner weld, the side-blown welding shielding gas is used; in the second corner weld, the laser is injected into the welding area in parallel to fuse the two layers of plates in the form of laser corner weld; in the second corner weld, the effective connection length of the two layers of plates connected by the weld is 0δ~2δ, where δ is the thickness of the plate, and the angle between the extension direction of the weld and the extension direction of the plate connection is α, where α ranges from 0° to 45°.

[0076] When the multi-cavity profile is a H-shaped tube profile, the roll forming method specifically includes the following steps:

[0077] Step S1: Roll bend one end of the sheet material toward the center of the sheet material to form the first bend structure 1; the first bend structure 1 is a right angle structure, forming the first welded connection structure;

[0078] Step S2: Roll bend the sheet material towards the center at a predetermined distance from the first bend structure 1 to form the second bend structure 2; the second bend structure 2 is an obtuse angle structure, and a first top wall 9 is formed between the first bend structure 1 and the second bend structure 2;

[0079] Step S3: Perform reverse roll bending on the non-forming area of ​​the sheet material at a preset length from the second bend structure 2 in the opposite direction to steps S1 and S2 to form the third bend structure 3; the third bend structure 3 is an arc-shaped bending structure.

[0080] Step S4: Roll bend the other end of the sheet towards the center of the sheet to form the seventh bend structure 7; the seventh bend structure 7 is a right angle structure, forming the second welded connection structure;

[0081] Step S5: Roller bend the sheet material towards the center at a predetermined distance from the seventh bend structure 7 to form the sixth bend structure 6; the sixth bend structure 6 is a right-angle structure, and a first support wall 11 is formed between the seventh bend structure 7 and the sixth bend structure 6;

[0082] Step S6: Roller bend the sheet material towards the center at a predetermined distance from the sixth bend structure 6 to form the fifth bend structure 5; the fifth bend structure 5 is a right-angle structure, and a second top wall 10 is formed between the sixth bend structure 6 and the fifth bend structure 5;

[0083] Step S7: Roller bend the sheet metal towards the center at a predetermined length from the fifth bend structure 5 to form the fourth bend structure 4, so that the seventh bend structure 7 abuts against the end of the third bend structure 3 away from the second bend structure 2, forming the first welding position 19 and the first cavity 16; the clearance area formed by the reverse roller bend of the third bend structure 3 forms the incident angle space 18 for the first weld laser to be driven into the first welding position 19; the fourth bend structure 4 is a right angle structure, and a second support wall 12 is formed between the fifth bend structure 5 and the fourth bend structure 4, and a first bottom wall 14 is formed between the fourth bend structure and the seventh bend structure 7; A is the welding area;

[0084] Step S8: Using laser welding equipment 24, the first weld laser is injected into the first welding position 19 through the incident angle space 18 to perform the first corner welding; the sixth bend structure 6, the two side structures of the sixth bend structure 6 and the seventh bend structure 7 are fixed by the first auxiliary roller 21, the fifth bend structure 5 and the two side structures of the fifth bend structure 5 are fixed by the second auxiliary roller 22, and the second bend structure 2, the two side structures of the second bend structure 2, the third bend structure 3 and the two side structures of the third bend structure 3 are supported by the lower roller 23;

[0085] Step S9: Roll bend the third corner structure 3 toward the center of the sheet material to adjust the third corner structure 3 into a flat wall structure; the flat wall structure is connected to the first bottom wall 14 and is parallel to the first bottom wall 14.

[0086] Step S10: Perform a second roll bending on the second bend structure 2 towards the center of the sheet material, and adjust the angle value of the second bend structure 2; the second bend structure 2 is a right angle structure;

[0087] Step S11: Roller bend the flat wall structure towards the center of the sheet at a predetermined distance from the second bend structure 2 to form the eighth bend structure 8, so that the first bend structure 1 abuts against the sixth bend structure 6 to form the second welding position 20 and the second cavity 17; the eighth bend structure 8 is a right angle structure, and a third support wall 13 is formed between the eighth bend structure 8 and the second bend structure 2; a second bottom wall 15 is formed between the eighth bend structure 8 and the seventh bend structure 7;

[0088] Step S12: Using laser welding equipment 24, a second weld laser is applied to the second welding position 20 to perform a second corner weld.

[0089] In the existing roll forming process of H-shaped tubes, the first welding is limited by the direction of the welding laser incident due to the roll forming process. The laser incident direction can only be from top to bottom, which is the lap welding process. The weld penetration and weld width are affected by the process characteristics, the process window is small, and welding defects such as incomplete welds and weld burn-through are prone to occur.

[0090] To solve the above-mentioned technical problems, this embodiment proposes a roll forming process, as shown in the figure, in which the non-bending area of ​​the H-shaped steel is bent in the opposite direction, and the right half is opened up due to the obstruction caused by the forming process, so that the laser incident angle can meet the requirements of fillet welding, thus realizing the process requirements of the first welding fillet welding of the H-shaped steel.

[0091] Example 2:

[0092] Those skilled in the art can understand this embodiment as a more specific description of Embodiment 1.

[0093] This embodiment provides a welding and forming method for H-shaped tubes. During the roll forming process, the H-shaped profile has two weld seams. To ensure welding process stability, an innovative H-shaped roll forming method is designed, changing the first weld from lap welding to fillet welding. This ensures welding process stability, increases welding speed, and guarantees more stable and efficient welding quality.

[0094] Roll forming die and forming roll design, such as Figure 4 As shown, during the process of forming the first cavity of the H-shaped tube, the non-forming area of ​​the sheet metal (red part) is bent in the opposite direction at a certain angle in advance to open the laser incident angle space of the first weld seam and realize the first welding forming fillet weld.

[0095] like Figure 5 The attached diagram shows a partial structure of the roll forming die. According to the designed forming roll pattern, the rolls are designed for each pass, so that the steel strip passes through the designed hole structure of the roll forming die according to the designed roll pattern. The steel plate is gradually bent to obtain the product cross-section diagram of each forming pass required by the design.

[0096] The reverse bending of the sheet metal in the non-formed area makes the connection direction of the sheet metal in the welding area A of the product cross section parallel to the incident direction of the laser, realizing the laser fillet welding method, increasing the effective connection length of the product weld, thereby improving the strength of the weld.

[0097] The working principle of roll forming dies: Each pass uses the assembly and cooperation of several rolls to form the die pattern required for that pass. After the sheet enters the roll forming pass, the R-angle area of ​​the sheet to be bent undergoes plastic deformation, completing the bending at the set angle. Through this gradual forming process, the product cross-section required by the design is obtained.

[0098] The technical effects achieved by the roll forming die are: a) more stable fillet welds are achieved in the first welding of the H-shaped tube; b) the first cavity of the first welding of the H-shaped tube is finally formed into a bend, achieving a larger angle bend design, reducing the empty bend angle design, allowing the R-angle to be formed more fully, and obtaining a more stable forming cross section.

[0099] like Figure 6 As shown, the process steps are as follows: a) First, gradually form bends 1, 2, 3, 7, 6, and 5, with angles ranging from 30-90°; then form bend 4 to 90° to achieve the first welded closed cavity of the H-shaped tube shown in the figure. Roll the formed section into the first welding pass, adjust the laser welding head, and let the laser enter the position to be welded from left to right. Control the welding focal length at 200-350mm, the welding speed at about 1-20m / min, and the welding power at 1000-8000kw, using side-blown welding shielding gas. The rolling equipment drives the sheet metal forward at a certain speed, while the laser head remains stationary and outputs a stable laser beam, which is parallel to the welding area A, fusing the two layers of sheet metal together in the form of laser fillet weld.

[0100] In existing H-shaped tube roll forming processes, the welding direction after the first weld is limited to top-to-bottom due to the roll forming process, thus requiring lap welding. To achieve a fillet weld for the first weld of the H-shaped steel, an innovative roll forming concept was designed. This involves recurving a portion of the non-formed area, opening up the laser incidence angle space for the first weld, and achieving a first-pass fillet weld. This first-pass fillet weld significantly increases the effective connection length of the weld, improves the stability of the welding process, and ensures the strength and quality of the weld.

[0101] This embodiment employs a reverse bending design for the non-formed area, breaking away from the traditional design approach of forming only the corresponding bending radius of the non-formed area. The innovative mold design opens up the right-side obstruction area, ensuring that the welding incident direction of the first weld seam requiring fillet welding is parallel to the laser head's incident angle, achieving more stable laser fillet welding. In existing technologies, the first weld of a H-shaped tube is typically performed from top to bottom, usually after the first closed H-shape is formed.

[0102] In the structural design method of this embodiment, high-strength steel is selected, and advanced roll forming technology is used for online one-piece molding, resulting in good product quality, high production stability, and high efficiency. Structurally, the main frame uses profiles to form four groove structures, which can be installed with T-bolts for external assembly. Simultaneously, adjustments can be made at any position within the grooves, making the frame assembly flexible and rapid.

[0103] The frame in this embodiment has no subsequent welding process, which reduces the investment of personnel and equipment, does not increase the additional energy consumption during production, and reduces costs. At the same time, with the help of various sheet metal connectors and bolts, it can be quickly assembled between profiles to create frames of different sizes and forms.

[0104] The overall frame of this embodiment can be disassembled and reassembled after its service life, enabling recycling and reuse, which is green and environmentally friendly.

[0105] This invention involves bending the non-formed area of ​​the sheet metal in the reverse direction at a certain angle in advance, opening up the laser incident angle space of the first weld seam, and realizing the first weld forming fillet weld, which not only improves the welding speed, but also ensures more stable and efficient welding quality.

[0106] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0107] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A roll forming method for multi-cavity profiles, characterized in that, Includes the following steps: During the process of forming the first cavity (16) by rolling and bending the sheet material, the non-forming area of ​​the first cavity of the sheet material corresponding to the welding position of the first cavity (16) is subjected to reverse rolling and bending to form a clearance area, which is used to drive the incident angle space (18) of the first weld laser. Using a laser welding device (24), the first weld laser is injected into the welding position through the incident angle space (18) to perform the first corner weld; in the first corner weld, the connection direction of the plate in the area to be welded is parallel to the incident direction of the laser, and the two plates are fused together by laser corner weld. After the corner welding is completed, the sheet material that has been reverse-bent is rolled to restore its shape before the reverse-bent bending. Then the sheet material is rolled to form the remaining cavity structure.

2. The roll forming method for multi-cavity profiles according to claim 1, characterized in that, The multi-cavity profile is a H-shaped tube profile; After the corner welding is completed, the sheet material that has been reverse rolled is rolled to restore its shape before the reverse roll bending. Then the sheet material is rolled and bent to form the second cavity (17). A second weld laser is applied to the welding position of the second cavity (17) to perform a second corner weld.

3. The roll forming method for multi-cavity profiles according to claim 2, characterized in that, The roll forming and welding method specifically includes the following steps: Step S1: Roller bend one end of the sheet towards the center of the sheet to form the first bend structure (1); Step S2: Roller bend the sheet material towards the center at a predetermined distance from the first bend structure (1) to form the second bend structure (2). Step S3: Perform reverse roll bending on the non-forming area of ​​the sheet material at a preset length from the second bend structure (2) in the opposite direction to steps S1 and S2 to form the third bend structure (3). Step S4: Roll bend the other end of the sheet towards the center of the sheet to form the seventh bend structure (7). Step S5: Roller bend the material towards the center of the sheet at a predetermined distance from the seventh bend structure (7) to form the sixth bend structure (6). Step S6: Roller bend the sheet material towards the center at a predetermined distance from the sixth bend structure (6) to form the fifth bend structure (5). Step S7: Roll bend the material towards the center of the sheet at a predetermined length from the fifth bend structure (5) to form the fourth bend structure (4), so that the seventh bend structure (7) abuts against the end of the third bend structure (3) away from the second bend structure (2) to form the first welding position (19) and the first cavity (16); the third bend structure (3) forms an incident angle space (18) for the first weld laser to be driven into the first welding position (19) by the clearance area formed by the reverse roll bend. Step S8: Using a laser welding device (24), the first weld laser is injected into the first welding position (19) through the incident angle space (18) to perform the first corner weld; Step S9: Roller bend the third corner structure (3) toward the center of the sheet metal to adjust the third corner structure (3) into a flat wall structure; Step S10: Perform a second roll bending of the second bend structure (2) towards the center of the sheet material, and adjust the angle value of the second bend structure (2); Step S11: Roller bend the flat wall structure at a predetermined length from the second bend structure (2) toward the center of the sheet to form the eighth bend structure (8), so that the first bend structure (1) abuts against the sixth bend structure (6) to form the second welding position (20) and the second cavity (17). Step S12: Using a laser welding device (24), a second weld laser is applied to the second welding position (20) to perform a second corner weld.

4. The roll forming method for multi-cavity profiles according to claim 1, characterized in that, In the first corner weld, the welding focal length is controlled at 200-350mm, the welding speed is about 1-20m / min, and the welding power is controlled at 1000-8000w.

5. The roll forming method for multi-cavity profiles according to claim 1, characterized in that, In the first fillet weld, a side-blown welding shielding gas is used.

6. The roll forming method for multi-cavity profiles according to claim 1, characterized in that, In the first fillet weld, the effective connection length of the two plates connected by the weld is 0δ~2δ, where δ is the thickness of the plate, and the angle between the extension direction of the weld and the extension direction of the plate connection is α, where α ranges from 0° to 45°.

7. The roll forming method for multi-cavity profiles according to claim 2, characterized in that, In the second corner weld, the welding focal length is controlled at 200-350mm, the welding speed is about 1-20m / min, and the welding power is controlled at 1000-8000w; In the second corner weld, a side-blown welding shielding gas is used; In the second corner weld, the laser is injected into the welding area in parallel, and the two layers of sheet metal are fused together by laser corner welding. In the second fillet weld, the effective connection length of the two plates connected by the weld is 0δ~2δ, where δ is the thickness of the plate, and the angle between the extension direction of the weld and the extension direction of the plate connection is α, where α ranges from 0° to 45°.

8. The roll forming method for multi-cavity profiles according to claim 3, characterized in that, In step S1, the first bend structure (1) is a right-angle structure, forming the first welded connection structure; In step S2, the second bend structure (2) is an obtuse angle structure, and a first top wall (9) is formed between the first bend structure (1) and the second bend structure (2). In step S3, the third bend structure (3) is an arc-shaped bend structure; In step S4, the seventh bend structure (7) is a right-angle structure, forming a second welded connection structure; In step S5, the sixth bend structure (6) is a right-angle structure, and the seventh bend structure (7) forms a first support wall (11) between the sixth bend structure (6). In step S6, the fifth bend structure (5) is a right-angle structure, and the sixth bend structure (6) forms a second top wall (10) between the fifth bend structure (5). In step S7, the fourth bend structure (4) is a right-angle structure, the fifth bend structure (5) and the fourth bend structure (4) form a second support wall (12), and the four bend structures and the seventh bend structure (7) form a first bottom wall (14). In step S9, the flat wall structure is connected to the first bottom wall (14) and is parallel to the first bottom wall (14); In step S10, the second bend structure (2) is a right-angle structure; In step S11, the eighth corner structure (8) is a right-angle structure, and a third support wall (13) is formed between the eighth corner structure (8) and the second corner structure (2); a second bottom wall (15) is formed between the eighth corner structure (8) and the seventh corner structure (7).

9. The roll forming method for multi-cavity profiles according to claim 3, characterized in that, In step S8, the sixth bend structure (6), the two side structures of the sixth bend structure (6), and the seventh bend structure (7) are fixed by the first auxiliary roller (21), the fifth bend structure (5) and the two side structures of the fifth bend structure (5) are fixed by the second auxiliary roller (22), and the second bend structure (2), the two side structures of the second bend structure (2), the third bend structure (3), and the two side structures of the third bend structure (3) are supported by the lower roller (23).

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