A laser-assisted roll forming method for a cross-section automobile beam structure

Abstract

The application discloses a laser-assisted roll forming method for a cross-section automobile beam structure, and relates to the field of automobile parts.The method comprises the following steps: preparing a plate; preparing a forming device; determining a roll forming track of a robot; fixing the plate on a tool; turning on a laser, and forming the plate according to a first track to obtain a first part; adjusting the relative position of the first part and a tool head, and enabling the tool head to act on a second plate; turning on the laser, and forming the first part according to a second track to obtain a second part; adjusting the relative position of the second part and the tool head, and enabling the tool head to act on a fourth plate; turning on the laser, and forming the second part according to a third track to obtain a third part; repeating the above steps to obtain another third part; and welding the two third parts into a cross-section part.The method can avoid the problems of plate springback and cracking at the bending part, and can realize high-precision, low-cost and rapid design change forming.

Description

Technical Field

[0001] This specification relates to the technical field of automotive parts, and particularly to a laser-assisted roll forming method for automotive beam-like structural parts with a rectangular cross-section. Background Art

[0002] The anti-collision beam with a rectangular cross-section is a common structural design for the front / rear anti-collision beams of automobiles, and the energy absorption effect is improved through a multi-chamber structure. The cross-sectional shape of the anti-collision beam with a rectangular cross-section is similar to the Chinese character "mu", which enhances the energy absorption capacity during collapse. It mostly uses high-strength materials such as 6-series aluminum alloy and 2200MPa hot-formed steel. The coverage rate of the front anti-collision beam is usually between 68% and 72%, and that of the rear anti-collision beam is about 70% to 74%.

[0003] In the prior art, the anti-collision beam with a rectangular cross-section is usually manufactured by stamping. The "mu" - shaped cross-section is formed through die stamping, and a multi-chamber structure (such as a six-cell grid, multiple folds) is designed inside. The main anti-collision beam and the auxiliary anti-collision beam (such as an aluminum alloy auxiliary beam) are connected by welding, and some vehicle models use a double-layer stamped steel plate auxiliary beam. Stamping is suitable for thin plates, with high precision, capable of producing parts with complex shapes, and high material utilization rate, but the die cost is relatively high.

[0004] In order to improve the strength of the anti-collision beam with a rectangular cross-section, high-strength and ultra-high-strength metal materials and roll forming processes are used to manufacture the anti-collision beam with a rectangular cross-section. The roll forming process is a new sheet metal bending forming process developed on the basis of the traditional roll forming process. It performs multi-pass progressive processing on the sheet metal by programming and controlling the forming trajectory of the robot, and finally obtains the target part. Compared with the traditional roll forming process, it has higher flexibility and can form parts with different cross-sectional shapes through standard tool heads; at the same time, it has higher flexibility and can meet the needs of small batches and customization. However, when forming high-strength and ultra-high-strength metal materials, problems such as severe springback of the sheet metal or easy cracking at the bending position are likely to occur. Therefore, the roll forming process has been difficult to meet the increasing forming requirements of high-strength and ultra-high-strength metal materials. Summary of the Invention

[0005] In view of the deficiencies of the prior art, an object of this specification is to provide a laser-assisted roll forming method for automotive beam-like structural parts with a rectangular cross-section, which can avoid the problems of sheet metal springback and easy cracking at the bending position, and can achieve high-precision, low-cost, and rapid design requirement changes for forming.

[0006] To achieve the above object, an embodiment of this specification provides a laser-assisted roll forming method for automotive beam-like structural parts with a rectangular cross-section, including the following steps: Step S10: Prepare the sheet metal; Step S20: Prepare the forming device; the forming device includes a robot, a tool head, a laser, and a fixture, wherein the tool head and the laser are mounted on the end of the robot facing the fixture; Step S30: Determine the roll forming trajectory of the robot; the roll forming trajectory includes a first trajectory, a second trajectory, and a third trajectory; Step S40: Fix the sheet metal onto the tooling; Step S50: Turn on the laser and shape the sheet metal according to the first trajectory to obtain a first part; the first part has a first plate and a second plate with equal size and perpendicular to each other; Step S60: Adjust the relative position of the first part and the tool head so that the tool head acts on the second plate; Step S70: Turn on the laser and shape the first part according to the second trajectory to obtain the second part; the second part includes the first plate, the third plate, and the fourth plate; the third plate is perpendicular to the first plate, and the fourth plate is parallel to the first plate; Step S80: Adjust the relative position of the second part and the tool head so that the tool head acts on the fourth plate; Step S90: Turn on the laser and shape the second part according to the third trajectory to obtain the third part; the third part includes the first plate, the third plate, the fifth plate and the sixth plate; the fifth plate is parallel to the first plate, the sixth plate is perpendicular to the first plate, and the sixth plate and the third plate have the same size; Step S100: Repeat steps S40 to S90 to obtain another third part, and weld the two third parts into a shaped part.

[0007] In a preferred embodiment, in step S40, the sheet metal is arranged vertically, with the lower half of the sheet metal located inside the tooling; the upper half of the sheet metal is located above the tooling and is used to contact the tool head.

[0008] In a preferred embodiment, step S60 includes: removing the first part from the fixture, and then fixing the second plate onto the fixture. At this time, the second plate is vertically positioned, with the portion of the second plate having the same size as the fourth plate located inside the fixture, and the remaining portion of the second plate located above the fixture for contact with the tool head.

[0009] In a preferred embodiment, step S80 includes: removing the second part from the fixture, and then fixing the fourth plate onto the fixture. At this time, the fourth plate and the first plate are vertically arranged, and the third plate is horizontally arranged. The portion of the fourth plate that is the same size as the fifth plate is located inside the fixture, and the remaining portion of the fourth plate is located above the fixture for contacting the tool head.

[0010] In a preferred embodiment, in step S10, the strength of the sheet metal is greater than or equal to 1000 mPa; the thickness of the sheet metal is 1.0 mm to 4.0 mm; and the material of the sheet metal is one of martensitic steel, DP steel or QP steel.

[0011] In a preferred embodiment, step S30 includes: Step S301: Write the robot control program using the KUKA language; Step S302: Mark the rolling forming trajectory of the tool head based on the thickness of the sheet metal and the bending angle of each pass; Step S303: Turn off the laser and do not add sheet metal. Run the tool head once under no-load based on the roll forming trajectory to verify the roll forming trajectory.

[0012] In a preferred embodiment, in step S30, the first trajectory includes bending the sheet material by 90°; the second trajectory includes bending the second sheet body by 90°; the third trajectory includes bending the fourth sheet body by 90°; the first trajectory, the second trajectory, and the third trajectory all include multiple bends, with each bend angle being 10°.

[0013] In a preferred embodiment, in step S50, the relative position of the tool head and the sheet metal in each pass is determined based on the total number of passes in the first part forming process; in step S70, the relative position of the tool head and the second sheet metal in each pass is determined based on the total number of passes in the second part forming process; and in step S90, the relative position of the tool head and the fourth sheet metal in each pass is determined based on the total number of passes in the third part forming process.

[0014] In a preferred embodiment, in steps S50, S70, and S90, the laser acts on the outer surface of the sheet metal; the laser spot is a specially designed spot, which is rectangular when irradiating the surface of the sheet metal, and the width of the rectangular spot is 2mm and the length is 4mm~8mm; the power of the laser is 600W~4000W; and the scanning rate of the laser is 10mm / s~350mm / s.

[0015] As a preferred embodiment, in steps S50, S70 and S90, the forming force applied by the robot is 100N to 4000N; step 90 further includes: welding the connection between the sixth plate body and the first plate body of the third part. Beneficial effects

[0016] The laser-assisted roll forming method for the automotive beam structure member with a mesh-shaped cross-section provided by this embodiment uses a forming device including a robot, a tool head, a laser and a tooling fixture to gradually form a high-precision automotive anti-collision beam with a mesh-shaped cross-section. The present invention has a large number of potential application prospects, and is particularly suitable for the high-precision forming of high-strength anti-collision beams for new energy vehicles.

[0017] The laser-assisted roll forming method of the present invention fabricates a mesh-shaped high-strength steel structure, which can be used for automotive anti-collision beams. Compared with the traditional crossbeam design, the mesh-shaped part has significant advantages in anti-collision and shock absorption performance. Its closed structure and multi-layer cross design can effectively disperse the impact energy, improve the energy absorption effect, reduce the concentration of collision force, and enhance the anti-collision performance. In addition, the mesh-shaped structure absorbs the impact force through elastic deformation during the impact process, reduces the vibration transmission, and thus better protects the safety of the occupants. Compared with the traditional crossbeam, the mesh-shaped part can achieve lightweight while improving the structural strength, and has more design flexibility to meet different customization requirements.

[0018] Compared with conventional cold forming, in the forming process of the present invention, through the local heating method of laser irradiation, the plastic forming of ultra-high strength steel is realized: the outer surface of the ultra-high strength steel is heated above the austenite transformation temperature to achieve the effect of local softening, which can significantly improve the plasticity of the ultra-high strength steel in the heated area, and further reduce springback.

[0019] Compared with stamping forming, the present invention can form a cross-section with a closed structure in a single process, which not only avoids the complexity of the mold in the traditional stamping method, but also can effectively control the deformation process of the material, making the geometric accuracy of the target cross-section structure higher.

[0020] Compared with traditional roll forming, the forming device based on industrial robots and laser technology of the present invention has high flexibility. Through software programming, the production line can be easily adjusted to adapt to different anti-collision beam designs without replacing complex molds or resetting the equipment. This makes the production line more adaptable to small-batch and diversified production requirements, and is particularly suitable for the production requirements of customized or high-end vehicles. The traditional roll forming process has strong adaptability to mass production, but when the production demand changes, it often requires re-designing and manufacturing new molds, and the adjustment process is relatively complex.

[0021] In summary, this application achieves high-precision, low-cost, and rapid forming of a crossbeam with varying design requirements by using a forming device comprising a robot, tool head, laser, and fixtures.

[0022] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope as a result.

[0023] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0024] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart illustrating the steps of a laser-assisted roll forming method for an automotive beam-type structural component with a V-shaped cross-section provided in this embodiment. Figure 2 for Figure 1 A schematic diagram of the sheet metal structure in step S10; Figure 3 for Figure 1 A schematic diagram of the forming device and sheet metal in step S20; Figure 4 This is a schematic diagram illustrating the principle of the laser-assisted roll forming process in this embodiment; Figure 5 To conduct Figure 1 A schematic diagram of the first part is obtained after step S50; Figure 6 To conduct Figure 1 A schematic diagram of the second part is obtained after step S70; Figure 7 To conduct Figure 1 A schematic diagram of the third part is obtained after step S90; Figure 8 To conduct Figure 1A schematic diagram of step S100; Figure 9 This is a comparative schematic diagram of a cold roll forming part and a laser-assisted roll forming part of this application; Figure 10 This is a schematic diagram comparing the stamping results with the laser-assisted roll forming results of this application.

[0027] Explanation of reference numerals in the attached figures: 1. Sheet metal; 11. First sheet metal; 12. Second sheet metal; 13. Third sheet metal; 14. Fourth sheet metal; 15. Fifth sheet metal; 16. Sixth sheet metal; 2. First part; 3. Second part; 4. Third part; 5. Robot; 6. Tool head; 7. Laser; 8. Fixture; 9. Welding point. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0029] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] Please see Figures 1 to 8 This application provides a laser-assisted roll forming method for automotive beam-type structural parts with a V-shaped cross-section, comprising the following steps (steps S10 to S100): Step S10: Prepare sheet material 1.

[0032] Among them, such as Figure 2As shown, the strength of sheet 1 is greater than or equal to 1000 mPa. The thickness of sheet 1 is 1.0 mm to 4.0 mm. The material of sheet 1 is one of martensitic steel, DP steel (duplex steel) or QP steel.

[0033] Step S20: Prepare the forming device.

[0034] Among them, such as Figure 3 As shown, the forming device includes a robot 5, a tool head 6, a laser 7, and a fixture 8. The tool head 6 and the laser 7 are mounted on the end of the robot 5 facing the fixture 8. The main function of the fixture 8 is to fix the metal sheet 1, ensuring that there is no relative displacement between the sheet 1 and the robot 5 during the forming process.

[0035] Step S30: Determine the rolling forming trajectory of robot 5.

[0036] Specifically, the roll forming trajectory includes a first trajectory, a second trajectory, and a third trajectory. For example... Figure 4 As shown, the first, second, and third tracks all include multiple bends, with each bend angle being 10°.

[0037] Step S30 includes: Step S301: Write the robot 5 control program using the KUKA language; Step S302: Mark the roll forming trajectory of the tool head 6 based on the thickness of the sheet 1 and the bending angle of each pass; Step S303: Turn off laser 7, do not add sheet metal 1, run tool head 6 once without load based on roll forming trajectory to verify roll forming trajectory.

[0038] Step S40: Fix the sheet metal 1 onto the tooling 8.

[0039] Specifically, sheet metal 1 is vertically positioned, with its lower half located within fixture 8. The upper half of sheet metal 1 is positioned above fixture 8 and is used to contact tool head 6.

[0040] Step S50: Turn on the laser 7 and shape the sheet metal 1 according to the first trajectory to obtain the first part 2.

[0041] like Figure 5 As shown, the first part 2 has a first plate 11 and a second plate 12 of equal size and perpendicular to each other. The first trajectory includes bending the plate 1 by 90°, so that the second plate 12 is perpendicular to the first plate 11. In step S50, the relative position of the tool head 6 and the plate 1 in each pass is determined based on the total number of passes in the forming process of the first part 2.

[0042] Step S60: Adjust the relative position of the first part 2 and the tool head 6 so that the tool head 6 acts on the second plate 12.

[0043] Specifically, step S60 includes: taking out the first part 2 from the fixture 8, and then fixing the second plate 12 on the fixture 8. At this time, the second plate 12 is set vertically, and the part of the second plate 12 that is the same size as the fourth plate 14 is located inside the fixture 8. The rest of the second plate 12 is located above the fixture 8 for contacting the tool head 6.

[0044] Step S70: Turn on the laser 7 and shape the first part 2 according to the second trajectory to obtain the second part 3.

[0045] like Figure 6 As shown, the second part 3 includes a first plate 11, a third plate 13, and a fourth plate 14. The third plate 13 is perpendicular to the first plate 11, and the fourth plate 14 is parallel to the first plate 11. The second trajectory includes bending the second plate 12 by 90°, so that the fourth plate 14 is perpendicular to the third plate 13. In step S70, the relative position of the tool head 6 and the second plate 12 in each pass is determined based on the total number of passes in the forming process of the second part 3.

[0046] Step S80: Adjust the relative position of the second part 3 and the tool head 6 so that the tool head 6 acts on the fourth plate 14.

[0047] Specifically, step S80 includes: removing the second part 3 from the fixture 8, and then fixing the fourth plate 14 onto the fixture 8. At this time, the fourth plate 14 and the first plate 11 are vertically arranged, and the third plate 13 is horizontally arranged. The part of the fourth plate 14 that is the same size as the fifth plate 15 is located inside the fixture 8, and the rest of the fourth plate 14 is located above the fixture 8 for contact with the tool head 6.

[0048] Step S90: Turn on the laser 7 and shape the second part 3 according to the third trajectory to obtain the third part 4.

[0049] like Figure 7 As shown, the third part 4 includes a first plate 11, a third plate 13, a fifth plate 15, and a sixth plate 16. The fifth plate 15 is parallel to the first plate 11, and the sixth plate 16 is perpendicular to the first plate 11. The sixth plate 16 and the third plate 13 have the same dimensions. The third trajectory includes bending the fourth plate 14 by 90°, so that the sixth plate 16 is perpendicular to the fifth plate 15. In step S90, the relative position of the tool head 6 and the fourth plate 14 in each pass is determined based on the total number of passes in the forming process of the third part 4.

[0050] Specifically, step 90 also includes welding the connection between the sixth plate and the first plate of the third part. To make the connection between the sixth plate and the first plate more stable, filler wire welding is used.

[0051] Step S100: Repeat steps S40 to S90 to obtain another third part 4. Weld the two third parts 4 together to form a U-shaped part. For example... Figure 8 As shown, there are two welding points 9. The resulting I-shaped part has good impact resistance and meets the requirements of GB17354-1998 Front and Rear End Protection Devices for Automobiles and GB 11551-2003 Occupant Protection in Frontal Collisions of Passenger Cars.

[0052] In one specific embodiment, the sheet material 1 has a length of 120mm, a width of 70mm, and a thickness of 1.0mm to 4.0mm. The first sheet 11, second sheet 12, third sheet 13, fourth sheet 14, fifth sheet 15, and sixth sheet 16 are all 120mm long. The first sheet 11 and second sheet 12 have a width of 35mm. The third sheet 13 has a width of 10mm, the fourth sheet 14 has a width of 25mm, the fifth sheet 15 has a width of 15mm, and the sixth sheet 16 has a width of 10mm.

[0053] In steps S50, S70, and S90, the laser 7 acts on the outer surface of the sheet metal 1. The laser spot of the laser 7 is a specially designed spot, which is rectangular when irradiating the surface of the sheet metal 1. The width of the rectangular spot is 2mm, and the length is 4mm~8mm (for example, 4mm, 5mm, 6mm, 7mm, or 8mm). During the forming process, the outer surface of the sheet metal 1 is subjected to tensile force, and the inner surface is subjected to compressive force. Due to the different stress conditions on the inner surface of the sheet metal 1, in order to ensure the forming accuracy and dimensional accuracy of the part, the power of the laser 7 is 600W~4000W. In order to ensure the forming accuracy and dimensional accuracy of the part, the scanning rate of the laser 7 is 10mm / s~350mm / s. The tool head 6 moves synchronously with the laser 7, and the rolling rate is the same as the scanning rate.

[0054] Furthermore, in steps S50, S70 and S90, the forming force applied by the robot 5 is 100N~4000N.

[0055] Based on the concept of incremental forming, the laser-assisted roll forming method in this application achieves the forming of a part with a V-shaped cross-section through multiple bending passes. The sheet metal 1 accumulates plastic deformation during the bending process to complete the part forming. Due to the use of multi-pass forming, the forming load is smaller compared to a one-step forming process. For metal materials with poor formability, such as ultra-high strength steel, titanium alloys, and aluminum alloys, the laser 7 installed on the side arm of the robot 5 preheats the bending area of ​​the sheet metal 1 in real time during the roll forming process, softening the material in the area to be deformed, thereby improving the material's formability.

[0056] Laser-assisted roll forming has significant process advantages compared to traditional processes. Traditional roll forming relies on molds, while laser-assisted roll forming does not require special molds, improving design flexibility, adapting to parts of various shapes and sizes, and is particularly suitable for small-batch and customized production. Laser heating can precisely control the local temperature of the material, improve the plasticity of the material, reduce the springback phenomenon, and thus enhance the forming accuracy and part quality. Compared with traditional cold forming, the laser-assisted process can effectively avoid excessive springback and crack problems, and is particularly suitable for high-strength materials and parts with complex shapes. The process adjustment is flexible, without the need to remanufacture molds, reducing the production cycle and cost, and improving production efficiency, especially in rapid response and small-batch production.

[0057] The laser-assisted roll forming method for the automotive beam-like structural member with a box-shaped cross-section provided in this embodiment gradually forms a high-precision automotive bumper beam with a box-shaped cross-section through a forming device including a robot 5, a tool head 6, a laser 7, and a tooling 8. The present invention has a large number of potential application prospects, and is particularly suitable for the high-precision forming of high-strength bumpers for new energy vehicles.

[0058] The laser-assisted roll forming method of the present invention fabricates a box-shaped high-strength steel structure, which can be used for automotive bumper beams. Compared with the traditional crossbeam design, the box-shaped part has significant advantages in anti-collision and shock absorption performance. Its closed structure and multi-layer cross design can effectively disperse the impact energy, improve the energy absorption effect, reduce the concentration of collision forces, and enhance the anti-collision performance. In addition, the box-shaped structure absorbs the impact force through elastic deformation during the impact process, reduces the vibration transmission, and thus better protects the safety of the occupants. Compared with the traditional crossbeam, the box-shaped part can achieve lightweight while improving the structural strength, and has more design flexibility to adapt to different customized requirements.

[0059] Compared with conventional cold forming, in the forming process of the present invention, through the way of local heating by irradiating the laser 7, the plastic forming of ultra-high-strength steel is realized: the outer surface of the ultra-high-strength steel is heated above the austenite transformation temperature to achieve the effect of local softening, which can significantly improve the plasticity of the ultra-high-strength steel in the heated area, and further reduce the springback.

[0060] Compared with stamping forming, the present invention can form a cross-section with a closed structure in a single process, not only avoiding the mold complexity in the traditional stamping method, but also effectively controlling the deformation process of the material, making the geometric accuracy of the target cross-section structure higher.

[0061] Compared to traditional roll forming, the forming device of this invention, based on industrial robots and laser technology, offers high flexibility. Through software programming, the production line can be easily adjusted to accommodate different anti-collision beam designs without the need to replace complex molds or reset equipment. This makes the production line more adaptable to small-batch, diversified production needs, particularly suitable for customized or high-end automotive production requirements. Traditional roll forming processes are highly adaptable to mass production, but when production demands change, new molds often need to be redesigned and manufactured, making the adjustment process complex.

[0062] In summary, this application achieves high-precision, low-cost, and rapid forming of a crossbeam with changing design requirements by using a forming device including a robot 5, a tool head 6, a laser 7, and a fixture 8 to form a crossbeam in stages.

[0063] To verify the technical effectiveness of the laser-assisted roll forming method for automotive beam-type structural parts with a U-shaped cross-section provided in this application, the following three embodiments and three comparative examples are provided. Example

[0064] In this embodiment, the sheet material is martensitic steel with a tensile strength of 1000 mPa, a room temperature elongation of not less than 5%, and a thickness of 2.0 mm. The laser power is 1200 W. The laser scanning rate is 10 mm / s. The size of the rectangular laser spot is 2 mm × 6 mm. Example

[0065] In this embodiment, the sheet material is martensitic steel with a tensile strength of 1300 mPa, a room temperature elongation of not less than 5%, and a thickness of 2.5 mm. The laser power is 2000 W. The laser scanning rate is 20 mm / s. The size of the rectangular laser spot is 2 mm × 6 mm. The distance between the laser and the sheet material along the laser direction is 25 mm, and the incident angle between the laser and the sheet material is 53°. Example

[0066] In this embodiment, the sheet material is martensitic steel with a tensile strength of 1700 mPa, a room temperature elongation of not less than 5%, and a thickness of 2.5 mm. The laser power is 3500 W. The laser scanning rate is 50 mm / s. The size of the rectangular laser spot is 2 mm × 6 mm. The distance between the laser and the sheet material along the laser direction is 25 mm, and the incident angle between the laser and the sheet material is 53°.

[0067] Comparative Example 1: The only difference from Example 1 is that Comparative Example 1 uses cold forming without laser. The following comparative analysis of the I-shaped steel parts prepared in Example 1 and Comparative Example 1 further illustrates the present invention: 1. Formability Analysis of the Robot Cold Rolling Formed Mesh-shaped Parts Figure 9 (a) shows the mesh-shaped part made in Comparative Example 1. It can be Figure 9 seen from (a) that the overall formability of the sheet metal is poor, with phenomena such as cracks and wrinkles. During the cold forming process, the sheet metal is completely at room temperature, and there is no heating process during forming, so there is no thermal gradient like laser heating. The plasticity of the entire material during cold forming is poor, especially for high-strength materials such as ultra-high-strength steel. Cold forming will face greater forming difficulties. Cold forming cannot change the internal structure of the material. Especially without heating, the fluidity of the material during forming is insufficient, which easily leads to stress concentration, thus increasing the risk of defects such as cracks and wrinkles. In addition, due to the limitations of cold forming, springback is also serious, and the forming accuracy is low.

[0068] Figure 9 (b) shows the mesh-shaped part made in Example 1. It can be seen from Figure 9 (b) that the springback of the mesh-shaped part obtained by laser-assisted processing is very small. Laser can fully heat the metal material, making the sheet metal soften sufficiently, so the plastic deformation ability is stronger and the formability is better.

[0069] 2. Surface Quality Analysis after Robot Cold Rolling Forming During the robot cold rolling forming process, the sheet metal undergoes plastic deformation directly through mechanical pressure at room temperature. Due to the absence of a heating process, the plasticity of the material is poor, especially for materials such as high-strength steel or ultra-high-strength steel. Cold rolling forming may cause obvious defects such as tensile lines, indentations, and wrinkles on the surface. Especially when forming complex geometric shapes, the fluidity of the material is poor and the force is uneven, which easily leads to surface unevenness.

[0070] Compared with cold rolling, laser-assisted rolling heats the local area through laser, making the surface and internal temperatures of the sheet metal evenly distributed, thereby improving the plasticity of the material, reducing springback and surface defects. Laser heating rapidly increases the local temperature of the material, reduces the material hardness, making it easier to flow during forming and having better plasticity. Therefore, it can avoid common surface defects such as tensile lines and indentations during cold rolling. At the same time, laser heating can reduce surface scratches and cracks caused by hardening during the forming process. Especially in the forming of high-strength materials, the surface quality is significantly improved.

[0071] 3. Forming Force Analysis during Robot Cold Rolling Forming In robotic cold rolling forming, the forming force is typically high because the sheet metal is directly subjected to mechanical forces at room temperature. Cold rolling primarily relies on high pressure to drive plastic deformation of the material, especially when forming high-strength or ultra-high-strength steel. These materials have high hardness and poor plasticity, requiring even greater pressure to complete the forming process. While the forming force requirements for cold rolling are generally relatively stable, they increase significantly during the forming of complex shapes or thick sheets. In these cases, the tools and molds experience considerable stress, which, if not properly controlled, can damage the equipment. Furthermore, the lack of heating during cold forming results in poor material flow, requiring the forming force to be mechanically transmitted to overcome significant resistance, further increasing energy consumption and equipment load throughout the process.

[0072] Compared to cold roll forming, laser-assisted roll forming reduces the hardness and yield strength of the material to some extent by heating the surface or internal areas of the material with a laser. Laser heating locally raises the temperature of the material, softening it and significantly improving its plastic deformation capacity, thereby reducing the required forming force. Because the heated material flows more easily, the pressure required during forming is significantly reduced, especially in complex or difficult-to-form areas, where laser heating can reduce the forming force demand. Laser-assisted roll forming not only reduces the burden on equipment while ensuring forming quality, but also improves forming efficiency and reduces wear on equipment and molds. Furthermore, the localized heating effect of the laser further optimizes the distribution of forming force, making the forming process smoother and reducing potential pressure fluctuations and anomalies during forming.

[0073] Comparative Example 2: The only difference from Example 1 is that Comparative Example 2 uses stamping, and the forming steps are as follows: S1. Sheet material feeding: Feed the sheet material into the stamping machine and position it to ensure that the material meets the forming requirements.

[0074] S2. Preliminary forming: Pressure is applied through a mold to complete the preliminary plastic deformation of the sheet metal, such as drawing, bending, or punching.

[0075] S3. Precision forming and finishing: Deburring, fine adjustment and finishing are performed to ensure that the size, shape and surface quality of the parts meet the requirements.

[0076] The following comparative analysis was performed on the eye-shaped steel parts prepared in Example 1 and Comparative Example 2 to further illustrate the present invention: 1. Formability Analysis of Stamping Figure 10(a) is a picture of the rectangular specimen obtained by stamping in Comparative Example 2. As can be seen from the figure, this process cannot complete the third step of bending, that is, it cannot complete the part with a closed cross-sectional structure and cannot meet the design requirements.

[0077] Figure 10 (b) is the forming process diagram of step S90 in Example 1. From Figure 10 (b), it can be seen that laser-assisted roll forming can be flexibly clamped and has high forming flexibility, meeting the design requirements.

[0078] Comparative Example 3: The difference from Example 1 is only that: Comparative Example 3 uses traditional roll forming, and the forming steps are as follows: S1. Sheet preparation and feeding: Feed the pre-cut sheet into the roll press equipment and ensure its correct positioning. At this time, the thickness, material, etc. of the sheet will be checked to ensure compliance with the forming requirements.

[0079] S2. Roll forming: Apply continuous pressure to the sheet through a series of rollers to gradually deform it and form the required cross-sectional shape. The pressure and angle of the rollers are adjusted according to the part design to complete different deformation tasks. [[ID=十七]]

[0080] S3. Trimming and leveling: After roll forming, the sheet is leveled, trimmed, and deburred to ensure that the surface of the part is smooth, the shape meets the design requirements, and the dimensional accuracy reaches the tolerance standard.

[0081] The following comparative analysis is carried out on the rectangular steel parts prepared in Example 1 and Comparative Example 3 to further illustrate the present invention: 1. Cost analysis of traditional roll forming and robot-assisted roll forming The following Table 1 is the detailed cost comparison between traditional roll forming and robot-assisted roll forming. In robot-assisted roll forming, the absence of a dedicated mold is one of its greatest advantages. This feature gives the process significant advantages in terms of flexibility and adaptability, especially suitable for small-batch production and scenarios with rapid response requirements. The traditional roll forming process usually requires dedicated molds, and the design, manufacturing, and maintenance costs of these molds are relatively high. Especially for each part with different shapes and specifications, a separate mold needs to be customized. The manufacturing cycle of the mold is long, and it needs to be regularly replaced or repaired after the mold wears, which greatly increases the production cost and downtime.

[0082] Robot-assisted roll forming, through highly automated and digital control, eliminates the need for complex, specialized molds, performing precise forming operations directly through programming and robotic arm control. The robot system can flexibly adjust its motion trajectory and forming parameters according to the part's design requirements, adapting to the processing of parts of different shapes, sizes, and materials. This means that the same equipment can handle different types of parts without additional investment in molds. For small-batch production and customized production needs, robot-assisted roll forming offers fast response times and greater production flexibility.

[0083] Table 1 Equipment costs Roller pressing equipment requires more mechanical devices and is therefore more expensive. The robot system, laser equipment, and control system are already in operation. Mold and tooling costs Customized special roller pressing dies are required, and the dies wear out quickly, resulting in high maintenance costs. No special molds are required, the tools are more durable, and have a longer service life. Labor costs It requires manual adjustment and equipment maintenance by operators, involving a significant amount of human intervention. Robots are highly automated and have lower labor costs. Energy consumption cost In traditional roll forming, energy consumption is mainly concentrated in the mechanical drive part, which has high energy consumption. Laser-assisted rolling process has high energy efficiency, but laser equipment consumes a lot of electricity, so the overall energy consumption is the same. Material utilization rate It makes high utilization of sheet metal, but may generate a large amount of waste during processing. Because the material deformation process is precisely controlled, there is less material waste and a higher utilization rate. Repair and maintenance costs Roller pressing equipment is relatively simple and has low maintenance and repair costs. Maintenance and repair costs are low. Time cost It is suitable for mass production and standardized products, but it has poor flexibility and is difficult to meet the needs of rapid prototyping. The response time is about 30 days. The robotic system is highly flexible and can quickly adapt to the production of parts of different shapes and materials, with a response time of one day. It should be noted that in the description of this specification, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this specification, unless otherwise stated, "a plurality of" means two or more.

[0084] Any numerical values ​​cited herein include all values ​​ranging from a lower limit to an upper limit, increasing by one unit, with at least two units between any lower and any higher value. For example, if the quantity of a component or the value of a process variable (e.g., temperature, pressure, time, etc.) is described as being from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in this specification. For values ​​less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1, etc. These are merely examples intended for explicit expression, and it can be assumed that all possible combinations of values ​​listed between the minimum and maximum values ​​are explicitly described in this specification in a similar manner.

[0085] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.

[0086] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.

[0087] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0088] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the inventors have not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A laser-assisted roll forming method for automotive beam-type structural parts with a U-shaped cross-section, characterized in that, Includes the following steps: Step S10: Prepare the sheet metal; Step S20: Prepare the forming device; The forming apparatus includes a robot, a tool head, a laser, and a fixture, wherein the tool head and the laser are mounted on the end of the robot facing the fixture; Step S30: Determine the roll forming trajectory of the robot; the roll forming trajectory includes a first trajectory, a second trajectory, and a third trajectory; Step S40: Fix the sheet metal onto the tooling; Step S50: Turn on the laser and shape the sheet metal according to the first trajectory to obtain the first part; The first part has a first plate and a second plate that are of equal size and perpendicular to each other; Step S60: Adjust the relative position of the first part and the tool head so that the tool head acts on the second plate; Step S70: Turn on the laser and shape the first part according to the second trajectory to obtain the second part; the second part includes the first plate, the third plate, and the fourth plate; the third plate is perpendicular to the first plate, and the fourth plate is parallel to the first plate; Step S80: Adjust the relative position of the second part and the tool head so that the tool head acts on the fourth plate; Step S90: Turn on the laser and shape the second part according to the third trajectory to obtain the third part; the third part includes the first plate, the third plate, the fifth plate and the sixth plate; the fifth plate is parallel to the first plate, the sixth plate is perpendicular to the first plate, and the sixth plate and the third plate have the same size; Step S100: Repeat steps S40 to S90 to obtain another third part, and weld the two third parts into a shaped part. In step S40, the sheet metal is arranged vertically, and the lower half of the sheet metal is located inside the tooling. The upper half of the sheet metal is located above the tooling and is used to contact the tool head; Step S60 includes: Remove the first part from the fixture, and then fix the second plate on the fixture. At this time, the second plate is set vertically. The part of the second plate with the same size as the fourth plate is located inside the fixture, and the rest of the second plate is located above the fixture for contact with the tool head. Step S80 includes: The second part is removed from the fixture, and then the fourth plate is fixed on the fixture. At this time, the fourth plate and the first plate are vertically arranged, and the third plate is horizontally arranged. The part of the fourth plate that is the same size as the fifth plate is located inside the fixture, and the rest of the fourth plate is located above the fixture for contact with the tool head. Step S30 includes: Step S301: Write the robot control program using the KUKA language; Step S302: Mark the rolling forming trajectory of the tool head based on the thickness of the sheet metal and the bending angle of each pass; Step S303: Turn off the laser and do not add sheet metal. Run the tool head once under no-load based on the roll forming trajectory to verify the roll forming trajectory. In step S30, the first trajectory includes bending the sheet material by 90°; the second trajectory includes bending the second sheet body by 90°; the third trajectory includes bending the fourth sheet body by 90°; the first trajectory, the second trajectory, and the third trajectory all include multiple bends, with each bend angle being 10°.

2. The laser-assisted roll forming method for automotive beam-type structural parts with a U-shaped cross-section according to claim 1, characterized in that, In step S10, the strength of the sheet metal is greater than or equal to 1000 MPa; the thickness of the sheet metal is 1.0 mm to 4.0 mm; and the material of the sheet metal is one of martensitic steel, DP steel or QP steel.

3. The laser-assisted roll forming method for automotive beam-type structural parts with a U-shaped cross-section according to claim 1, characterized in that, In step S50, the relative position of the tool head and the sheet metal in each pass is determined based on the total number of passes in the first part forming process; in step S70, the relative position of the tool head and the second sheet metal in each pass is determined based on the total number of passes in the second part forming process; in step S90, the relative position of the tool head and the fourth sheet metal in each pass is determined based on the total number of passes in the third part forming process.

4. The laser-assisted roll forming method for automotive beam-type structural parts with a U-shaped cross-section according to claim 1, characterized in that, In steps S50, S70, and S90, the laser acts on the outer surface of the sheet metal; the laser spot is a specially designed spot, which is rectangular when irradiating the surface of the sheet metal, with a width of 2 mm and a length of 4 mm to 8 mm; the laser power is 600 W to 4000 W; and the laser scanning rate is 10 mm / s to 350 mm / s.

5. The laser-assisted roll forming method for automotive beam-type structural parts with a U-shaped cross-section according to claim 1, characterized in that, In steps S50, S70 and S90, the forming force applied by the robot is 100N~4000N; step 90 further includes welding the connection between the sixth plate and the first plate of the third part.

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