Laser and aerosol synergistic shape control apparatus for robotic incremental forming

Abstract

The application discloses a laser and gas mist synergistic shape control device for robot incremental forming, which comprises a first robot and a second robot arranged on two sides of a plate respectively; the first robot and the second robot are kept relatively static at all times; the first robot is fixedly provided with a first tool head, a first laser and a first gas mist nozzle, and the first tool head, the first laser and the first gas mist nozzle are kept relatively static at all times; the first laser and the first gas mist nozzle are located on two sides of the first tool head respectively; the area of a coverage area of gas mist sprayed by the first gas mist nozzle is 1.5-5 times the area of an irradiation area of laser emitted by the first laser; the second robot is fixedly provided with a second laser and a second gas mist nozzle, and the second laser and the second gas mist nozzle are kept relatively static at all times; the area of a coverage area of gas mist sprayed by the second gas mist nozzle is 1.5-5 times the area of an irradiation area of laser emitted by the second laser. The device can improve forming precision and forming quality.

Description

Technical Field

[0001] This specification relates to the field of high-precision forming technology for ultra-high strength steel, and in particular to a laser and aerosol collaborative shape control device and method for robotic incremental forming. Background Technology

[0002] Laser-assisted robotic roll forming is a novel sheet metal progressive bending process developed from traditional roll forming. It uses programmed robot trajectory control to perform multi-pass progressive processing on sheet metal, ultimately obtaining the target part. Compared to traditional roll forming, it offers higher flexibility, enabling the forming of parts with different cross-sectional shapes using standard tool heads; it also provides greater flexibility to meet the needs of small-batch, customized production.

[0003] Based on the laser-assisted robot roll forming process, for thicker ultra-high strength steel plates of 1.5mm to 2.0mm, by changing the size of the laser spot, increasing the number of support rollers and increasing the number of lasers, we have successively developed a dual-laser-assisted single-robot roll forming process and a dual-laser-assisted dual-robot roll forming process, which have achieved high-precision, small-rounded, and damage-free forming of thicker ultra-high strength steel plates.

[0004] Based on the idea of ​​softening sheet metal through laser heating, the laser-assisted robotic precision roll forming process uses a highly concentrated laser beam to locally heat the forming area of ​​the sheet metal, improving the plasticity of the forming area and thus achieving high-precision forming of ultra-high-strength steel sheets. Laser heating is an extremely hot and cold process. In the laser-assisted roll forming process, it only takes about 1.0 second to increase the temperature from room temperature to 1300℃ and then back to room temperature. However, within this 1.0 second time range, a large number of metal phase transformations and grain refinement occur. At the same time, due to the temperature difference of up to about 1000℃ between the surface and the interior of the sheet metal, the metallographic arrangement in the bending area exhibits a gradient distribution along the thickness direction of the sheet metal. Furthermore, there are excessive differences in microhardness between different parts of the bending area. Therefore, it is easy to encounter problems such as difficulty in controlling the dimensional accuracy of the bent parts and unstable mechanical properties, making it difficult to obtain good forming accuracy and quality. Utility Model Content

[0005] In view of the shortcomings of the prior art, at least one objective of this specification is to provide a laser and aerosol co-control device for robotic incremental forming, which can improve forming accuracy and forming quality.

[0006] To achieve the above objectives, the embodiments described in this specification are provided.

[0007] A laser and aerosol co-control shaping device for robotic incremental forming includes: a first robot and a second robot respectively disposed on both sides of a sheet metal; the first robot and the second robot remain relatively stationary at all times; the first robot is fixedly equipped with a first tool head, a first laser, and a first aerosol nozzle, which remain relatively stationary at all times; the first laser and the first aerosol nozzle are respectively located on both sides of the first tool head; the second robot is fixedly equipped with a second laser and a second aerosol nozzle, which remain relatively stationary at all times.

[0008] Preferably, the second aerosol nozzle is configured such that the area of ​​the aerosol it sprays is larger than the area of ​​the irradiated region of the laser emitted by the second laser.

[0009] Preferably, the area covered by the aerosol sprayed from the second aerosol nozzle is 1.5 to 5 times the area of ​​the irradiated area of ​​the laser emitted by the second laser.

[0010] Preferably, the first aerosol nozzle is configured such that the area of ​​the aerosol it sprays is larger than the area of ​​the irradiated area of ​​the laser emitted by the first laser.

[0011] Preferably, the area covered by the aerosol sprayed from the first aerosol nozzle is 1.5 to 5 times the area of ​​the irradiated area of ​​the laser emitted by the first laser.

[0012] Preferably, the spot of the first laser is rectangular when it irradiates the surface of the sheet metal, and the length of the rectangular spot is 4~10mm and the width is 2mm.

[0013] Preferably, the spot of the second laser is circular when it irradiates the surface of the sheet metal, and the radius of the circular spot is 1~10mm.

[0014] Preferably, the device further includes tooling fixtures for fixing the sheet metal.

[0015] Preferably, the second robot is also fixedly equipped with a second tool head, which remains relatively stationary with respect to the second laser at all times.

[0016] Preferably, the second laser and the second aerosol nozzle are located on opposite sides of the second tool head.

[0017] A laser and aerosol co-control shaping device for robotic incremental forming includes: a first robot and a second robot respectively disposed on both sides of a sheet metal; the first robot and the second robot remain relatively stationary at all times; the first robot is fixedly equipped with a first tool head, a first laser, and a first aerosol nozzle, which remain relatively stationary at all times; the first laser and the first aerosol nozzle are respectively located on both sides of the first tool head; the area covered by the aerosol sprayed by the first aerosol nozzle is 1.5 to 5 times the area irradiated by the laser emitted by the first laser; the second robot is fixedly equipped with a second laser and a second aerosol nozzle, which remain relatively stationary at all times; the area covered by the aerosol sprayed by the second aerosol nozzle is 1.5 to 5 times the area irradiated by the laser emitted by the second laser.

[0018] In a preferred embodiment, the spot of the first laser is rectangular when it irradiates the surface of the sheet metal, and the rectangular spot has a length of 4-10 mm and a width of 2 mm.

[0019] In a preferred embodiment, the spot of the second laser is circular when it irradiates the surface of the sheet metal, and the radius of the circular spot is 1~10mm.

[0020] In a preferred embodiment, the device further includes a tooling fixture for fixing the sheet metal; the second robot is also fixedly mounted with a second tool head, which remains relatively stationary with respect to the second laser at all times; the second laser and the second aerosol nozzle are located on opposite sides of the second tool head.

[0021] This specification provides a laser and aerosol co-control method for robot incremental forming, which is implemented using a laser and aerosol co-control device for robot incremental forming as described in any of the above embodiments. The method includes the following steps:

[0022] Step S10: Determine the roll forming trajectories of the first robot and the second robot; the first robot is positioned facing the outer surface of the sheet metal, and the second robot is positioned facing the inner surface of the sheet metal;

[0023] Step S20: Fix the sheet metal onto the tooling fixture; the sheet metal has a tensile strength of 1180MPa or higher and a thickness of 1.0~4.0mm;

[0024] Step S30: Turn on the first laser, the first aerosol nozzle, the second laser, and the second aerosol nozzle, and shape the sheet material based on the forming trajectory.

[0025] In a preferred embodiment, in step S30, after the surface of the sheet metal is cooled by the first or second aerosol nozzle, the cooling rate is between 50°C / s and 200°C / s.

[0026] In a preferred embodiment, in step S30, the power of the first laser is 600~4000W, and the power of the second laser is 100~3500W.

[0027] In a preferred embodiment, in step S30, the scanning rate of the first laser and the second laser is 10 mm / s to 350 mm / s.

[0028] In a preferred embodiment, in step S30, the forming force applied by the first robot or the second robot is 100~4000N.

[0029] In a preferred embodiment, in step S30, the microhardness fluctuation between different parts of the bending area of ​​the formed part does not exceed 30%.

[0030] Beneficial effects:

[0031] The laser and aerosol co-control forming device for robotic incremental forming provided in this embodiment combines the aerosol nozzle with the laser-assisted robotic roll forming process by setting a first laser and a first aerosol nozzle on a first robot and a second laser and a second aerosol nozzle on a second robot. This effectively improves the situation where the grain size gradient distribution and microhardness of ultra-high strength steel are significantly reduced in the bending area during the forming process, while improving the forming accuracy, forming quality and mechanical properties of the parts. This utility model has a large number of potential applications, especially suitable for high-precision forming of battery pack frames and other body parts for new energy vehicles.

[0032] Compared with conventional laser-assisted robot roll forming process, this invention achieves an ultra-cooling process for ultra-high strength steel by reducing the temperature of the forming area through a first aerosol nozzle and a second aerosol nozzle during the forming process: the lasers emitted by the first and second lasers heat the ultra-high strength steel to above the austenite transformation temperature. After forming, the low-temperature water mist sprayed by the first and second aerosol nozzles is used to quickly cool the bending area, reduce the temperature gradient distribution inside the sheet, reduce the temperature difference between different positions in the thickness direction of the sheet, refine the grains sufficiently, optimize the grain gradient distribution in the bending area, and make the mechanical properties of the sheet more balanced at the bending point.

[0033] Compared with conventional laser-assisted robot roll forming process, this invention achieves stress release of ultra-high strength steel by reducing the temperature of the forming area through a first aerosol nozzle and a second aerosol nozzle during the forming process. When bending ultra-high strength steel in conventional laser-assisted robot roll forming process, there is a large temperature difference in the thickness direction of the sheet, resulting in a serious uneven distribution of thermal stress in different areas. By instantly reducing the temperature of the forming area through the first and second aerosol nozzles, the temperature difference in the thickness direction can be effectively reduced, alleviating the uneven distribution of thermal stress, reducing residual stress, reducing sheet springback, and thus improving the forming accuracy of the sheet.

[0034] Furthermore, in the device provided by this utility model, by adding a first aerosol nozzle and a second aerosol nozzle, and by setting appropriate laser spot sizes for the first and second lasers, and aerosol influence ranges for the first and second aerosol nozzles, the problems of material thickness direction temperature gradient distribution, grain size gradient distribution, microhardness gradient distribution, and large thermal stress that occur during the laser-assisted robot roll forming process are improved.

[0035] 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 present invention can be employed. It should be understood that the scope of the embodiments of the present invention is not limited thereto.

[0036] 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.

[0037] 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

[0038] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of a laser and aerosol co-control shaping device for robot incremental forming provided in this embodiment during operation;

[0040] Figure 2 for Figure 1 Side view;

[0041] Figure 3 for Figure 1 A schematic diagram of the structure after the equipment in the diagram bends the sheet metal;

[0042] Figure 4 for Figure 3 Side view;

[0043] Figure 5 This is a schematic diagram of the structure of another laser and aerosol co-control shaping device for robot incremental forming provided in this embodiment during operation;

[0044] Figure 6 for Figure 5 Side view;

[0045] Figure 7 for Figure 5 A schematic diagram of the structure after the equipment in the diagram bends the sheet metal;

[0046] Figure 8 for Figure 7 Side view;

[0047] Figure 9 This is a flowchart illustrating the steps of a laser and aerosol co-control method for incremental forming of robots provided in this embodiment.

[0048] Figure 10 A schematic diagram of a part formed by single-point laser-assisted single-robot roll forming as shown in Comparative Example 1;

[0049] Figure 11 This is a schematic diagram of the surface of a part formed by single-point laser-assisted single-robot roll forming in Comparative Example 1.

[0050] Figure 12 This is a schematic diagram of the outer surface of a part formed by roll forming using the equipment in Example 1;

[0051] Figure 13 This is a schematic diagram of the inner surface of a part formed by roll forming using the equipment in Example 1;

[0052] Figure 14 The images shown are metallographic photographs of the bending area at different locations along the thickness direction in Comparative Example 1. Figure 14 (a) Figure 14 (b) Figure 14 (c) are metallographic photographs of the outer, middle and inner layers at the bend of Comparative Example 1, respectively;

[0053] Figure 15 These are metallographic photographs of the bending area at different locations along the thickness direction in Example 1. Figure 15 (a) Figure 15 (b) Figure 15(c) are metallographic photographs of the outer, middle and inner layers at the bend in Example 1, respectively;

[0054] Figure 16 This is a schematic diagram showing the sampling points for microhardness testing in Example 1 and Comparative Example 1. Figure 16 (a) The red line represents the microhardness test area outside the bending area. Figure 16 (a) The yellow line in the middle represents the microhardness test area inside the bending area. Figure 16 (b) Figure 16 (c) The locations of microhardness measurements of the outer and inner layers of the bending area of ​​the part obtained in Example 1 are shown respectively. Figure 16 (d) Figure 16 (e) are the microhardness points of the outer and inner layers of the bending area of ​​the part obtained in Comparative Example 1, respectively.

[0055] Figure 17 This is a comparison chart of the microhardness test results of the bending area of ​​the part obtained in Example 1;

[0056] Figure 18 Comparison of the microhardness test results of the bending area of ​​the part obtained in Comparative Example 1;

[0057] Figure 19 Here is a metallographic photograph of the bending area in Comparative Example 2. Figure 19 (a) Figure 19 (b) Figure 19 (c) are metallographic photographs of the outer, middle and inner layers of the bending region in Comparative Example 2, respectively;

[0058] Figure 20 This is a metallographic photograph of the bending area in Example 3. Figure 20 (a) Figure 20 (b) Figure 20 (c) are metallographic photographs of the outer, middle and inner layers of the bending area in Example 3, respectively.

[0059] Explanation of reference numerals in the attached figures:

[0060] 1. First robot; 11. First tool head; 12. First laser; 13. First aerosol nozzle; 2. Second robot; 21. Second tool head; 22. Second laser; 23. Second aerosol nozzle; 3. Tooling fixture; 4. Sheet metal; 41. Outer surface; 42. Inner surface. Detailed Implementation

[0061] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0062] 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.

[0063] 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 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.

[0064] Please see Figures 1 to 4 This application provides a laser and aerosol collaborative shaping device for robotic incremental forming, comprising: a first robot 1 and a second robot 2 respectively disposed on both sides of a sheet metal 4. The first robot 1 and the second robot 2 remain relatively stationary at all times, that is, the first robot 1 and the second robot 2 move synchronously. The first robot 1 is fixedly mounted with a first tool head 11, a first laser 12, and a first aerosol nozzle 13. The first tool head 11 is used to perform operations such as bending on the sheet metal 4. The first tool head 11, the first laser 12, and the first aerosol nozzle 13 remain relatively stationary at all times, that is, the first tool head 11, the first laser 12, and the first aerosol nozzle 13 move synchronously. The first laser 12 and the first aerosol nozzle 13 are respectively located on both sides of the first tool head 11.

[0065] In the forward direction of the first tool head 11, the first laser 12 is located in front of the first tool head 11, and the first aerosol nozzle 13 is located behind the first tool head 11. During the forming process, the first laser 12 first heats the sheet metal 4, then the first tool head 11 performs the forming, and finally the first aerosol nozzle 13 cools it.

[0066] The second robot 2 is fixedly equipped with a second laser 22 and a second aerosol nozzle 23. The second laser 22 and the second aerosol nozzle 23 remain relatively stationary at all times, that is, the second laser 22 and the second aerosol nozzle 23 move synchronously.

[0067] The laser and aerosol co-control forming device for robot incremental forming provided in this embodiment combines the aerosol nozzle with the laser-assisted robot roll forming process by setting a first laser 12 and a first aerosol nozzle 13 on the first robot 1 and a second laser 22 and a second aerosol nozzle 23 on the second robot 2. This effectively improves the situation of grain size gradient distribution and significant reduction in microhardness in the bending area of ​​ultra-high strength steel during the forming process, while improving the forming accuracy, forming quality and mechanical properties of the parts. This utility model has a lot of potential application prospects, especially suitable for high-precision forming of battery pack frames and other body parts for new energy vehicles.

[0068] Compared with conventional laser-assisted robot roll forming process, this invention achieves an ultra-cooling process for ultra-high strength steel by reducing the temperature of the forming area through the first aerosol nozzle 13 and the second aerosol nozzle 23 during the forming process: the laser emitted by the first laser 12 and the second laser 22 heats the ultra-high strength steel to above the austenite transformation temperature. After forming, the low-temperature water mist sprayed by the first aerosol nozzle 13 and the second aerosol nozzle 23 is used to achieve rapid cooling of the bending area, reduce the temperature gradient distribution inside the sheet 4, reduce the temperature difference between different positions in the thickness direction of the sheet 4, refine the grains sufficiently, optimize the grain gradient distribution in the bending area, and make the mechanical properties of the sheet 4 more balanced at the bending point.

[0069] Compared with conventional laser-assisted robot roll forming process, this invention achieves stress release of ultra-high strength steel by reducing the temperature of the forming area through the first aerosol nozzle 13 and the second aerosol nozzle 23 during the forming process. When bending ultra-high strength steel in conventional laser-assisted robot roll forming process, there is a large temperature difference in the thickness direction of the sheet 4, resulting in a serious uneven distribution of thermal stress in different areas. By instantly reducing the temperature of the forming area through the first aerosol nozzle 13 and the second aerosol nozzle 23, the temperature difference in the thickness direction can be effectively reduced, alleviating the uneven distribution of thermal stress, reducing residual stress, reducing the springback of the sheet 4, and thus improving the forming accuracy of the sheet 4.

[0070] In this embodiment, such as Figure 1 and Figure 4As shown, the first robot 1 is positioned facing the outer surface 41 of the sheet metal 4, and the second robot 2 is positioned facing the inner surface 42 of the sheet metal 4. Thus, the first laser 12 and the first aerosol nozzle 13 fixed on the first robot 1 act on the outer surface 41 of the sheet metal 4, and the second laser 22 and the second aerosol nozzle 23 fixed on the second robot 2 act on the inner surface 42 of the sheet metal 4. The sheet metal 4 is bent from the outer surface 41 to the inner surface 42 by the first robot 1 and the second robot 2. The light spot of the first laser 12 is a specially designed light spot, which is rectangular when irradiating the surface of the sheet metal 4. The length of the rectangular light spot is 4~10mm, and the width is 2mm. Therefore, the size of the rectangular light spot can be 2×4mm, 2×5mm, 2×6mm, 2×7mm, 2×8mm, and 2×10mm.

[0071] Specifically, the spot of the second laser 22 is circular when irradiating the surface of the sheet 4, and its heat distribution is Gaussian. The radius of the circular spot is 1~10mm. During the actual forming process of the sheet 4, due to the bending of the sheet 4, the forming area is arc-shaped. Setting the spot of the first laser 12 to be rectangular allows the rectangular spot to achieve maximum coverage of the bending area and uniform distribution of laser energy along the arc of the bending area during the forming process. However, for the inner surface 42, the material is relatively concentrated due to the extrusion during the forming process. The second laser 22 is set on the inner surface 42 to alleviate the temperature gradient distribution along the thickness direction of the sheet 4 when only the outer surface 41 is heated, which ultimately leads to the inner surface 42 being too cold to form. Therefore, heating the inner surface 42 is only for heating the part of the bending area close to the inner surface 42. Therefore, the second laser 22 can be a relatively common circular spot with a Gaussian energy distribution.

[0072] In this embodiment, the effective range of the cooling liquid ejected by the aerosol nozzle needs to be determined based on the spot size. Specifically, by adjusting parameters such as the position and irradiation direction of the first aerosol nozzle 13 and the first laser 12 (e.g., adjusting their respective distances from their corresponding areas), the area covered by the aerosol ejected by the first aerosol nozzle 13 is larger than the irradiation area of ​​the laser emitted by the first laser 12. Further, the area covered by the aerosol ejected by the first aerosol nozzle 13 is 1.5 to 5 times the irradiation area of ​​the laser emitted by the first laser 12. Similarly, the area covered by the aerosol ejected by the second aerosol nozzle 23 is larger than the irradiation area of ​​the laser emitted by the second laser 22. Further, the area covered by the aerosol ejected by the second aerosol nozzle 23 is 1.5 to 5 times the irradiation area of ​​the laser emitted by the second laser 22. If the cooling range of the aerosol nozzle is too small, it cannot completely cover the heat-affected zone; if the cooling range of the aerosol nozzle is too large, it will affect the area to be heated, compromising process stability.

[0073] Furthermore, in the device provided by this utility model, by increasing the first aerosol nozzle 13 and the second aerosol nozzle 23, and by setting appropriate laser spot sizes for the first laser 12 and the second laser 22, and aerosol influence ranges for the first aerosol nozzle 13 and the second aerosol nozzle 23, the problems of material thickness direction temperature gradient distribution, grain size gradient distribution, microhardness gradient distribution and large thermal stress that occur during the laser-assisted robot roll forming process are improved.

[0074] Specifically, the equipment also includes a fixture 3 for fixing the sheet metal 4, ensuring that there is no relative displacement between the sheet metal 4 and the fixture 3 during the forming process. Figures 5 to 8 As shown, the second robot 2 is also fixedly equipped with a second tool head 21. The second tool head 21 and the second laser 22 remain relatively stationary at all times, that is, the second tool head 21, the second laser 22, and the second aerosol nozzle 23 move synchronously. The second tool head 21 can cooperate with the first tool head 11 to bend the sheet metal 4. The second laser 22 and the second aerosol nozzle 23 are located on both sides of the second tool head 21. In the forward direction of the second tool head 21, the second laser 22 is located in front of the second tool head 21, and the second aerosol nozzle 23 is located behind the second tool head 21.

[0075] The plate 4 used in the device of this application is made of metal sheet, such as martensitic steel, duplex steel (DP steel) or QP steel. The tensile strength of plate 4 is 1180MPa or above, and the thickness is 1.0~4.0mm.

[0076] Based on the same concept, this utility model embodiment also provides a laser and aerosol collaborative shape control method for robot incremental forming, which is implemented using the laser and aerosol collaborative shape control device for robot incremental forming as described in any of the above embodiments. Figure 9 As shown, the method includes the following steps:

[0077] Step S10: Determine the roll forming trajectory of the first robot 1 and the second robot 2;

[0078] Step S20: Fix the sheet metal 4 onto the tooling fixture 3;

[0079] Step S30: Turn on the first laser 12, the first aerosol nozzle 13, the second laser 22 and the second aerosol nozzle 23, and shape the sheet 4 based on the forming trajectory.

[0080] In this embodiment, the method implementation corresponds to the device implementation and can solve the technical problems solved by the device implementation, thereby achieving the technical effects of the device implementation. The specific details will not be elaborated here.

[0081] Step S10 specifically includes the following steps:

[0082] Step S101: Write the robot control program using the KUKA language;

[0083] Step S102: Mark the forming trajectory of the first tool head 11 (or the first tool head 11 and the second tool head 21) based on the thickness of the sheet 4 and the bending angle of each pass;

[0084] Step S103: Based on the forming trajectory obtained in step S102, keep the first laser 12, the first aerosol nozzle 13, the second laser 22 and the second aerosol nozzle 23 closed, and do not add sheet metal 4. Run the form-forming trajectory once under no-load to verify it.

[0085] Specifically, in step S30, after the surface of the sheet 4 is cooled by the first aerosol nozzle 13 or the second aerosol nozzle 23, the cooling rate is between 50℃ / s and 200℃ / s.

[0086] In step S30, the outer surface 41 of the sheet metal 4 is subjected to tensile force, and the inner surface 42 is subjected to compressive force. Because the stress conditions on the inner and outer surfaces of the sheet metal 4 are different, to ensure the forming accuracy and dimensional accuracy of the part, the power of the first laser 12 is 600~4000W, and the power of the second laser 22 is 100~3500W. To ensure the forming accuracy and dimensional accuracy of the part, the scanning rate of the first laser 12 and the second laser 22 is 10mm / s~350mm / s.

[0087] In step S30, the bending angle of sheet 4 is 10° in each rolling pass. After multiple rolling passes, the sheet 4 is bent to the required angle. The forming force applied by the first robot 1 or the second robot 2 during the forming process is 100~4000N. The microhardness fluctuation between different parts of the bending area of ​​the part formed by the above method does not exceed 30%.

[0088] In a specific embodiment 1, the following is adopted: Figures 1 to 4 The laser and aerosol co-control shaping equipment for robotic incremental forming forms L-shaped parts from martensitic steel sheet 4. During the processing, dual robots, a single tool head, and a dual-point laser are used to simultaneously and locally heat the bending area of ​​sheet 4, while dual aerosol nozzles are used to cool the forming area.

[0089] In this embodiment, the ultra-high strength steel has a tensile strength of 1500MPa, a room temperature elongation of not less than 5%, and a thickness of 1.5mm.

[0090] Specifically, the ultra-high strength sheet 4 is clamped by the tooling fixture 3, and the first tool head 11 is used to roll and form the sheet 4 according to the shape of the target part. During the forming process, the first laser 12 and the second laser 22 simultaneously heat the ultra-high strength sheet 4 locally to assist in the forming of the ultra-high strength steel sheet 4. At the same time, the first aerosol nozzle 13 and the second aerosol nozzle 23 play the role of cooling the bending area of ​​the sheet 4 in real time.

[0091] In step S30, the first tool head 11 and the first laser 12 move synchronously. The rolling rate of the first tool head 11 and the scanning rate of the first laser 12 are the same, both being 10 mm / s. The first robot 1 is simultaneously fixed with the first tool head 11, the first laser 12, and the first aerosol nozzle 13. The distance between the first laser 12 and the sheet metal 4 along the direction of the first laser 12 is 25 mm, the incident angle between the first laser 12 and the sheet metal 4 is 53°, and the power of the first laser 12 is 1200W. The distance between the first aerosol nozzle 13 and the first laser 12 along the direction of the first laser 12 is 5 mm, the incident angle between the first aerosol nozzle 13 and the sheet metal 4 is 45°, the flow rate of the first aerosol nozzle 13 is 1 L / min, and the coverage area of ​​the first aerosol nozzle 13 is 24 mm². 2 A second laser 22 and a second aerosol nozzle 23 are fixed on the second robot 2. The second laser 22 is always perpendicular to the sheet metal 4, and the power of the second laser 22 is 800W. The distance between the second aerosol nozzle 23 and the second laser 22 along the direction of the second laser 22 is 5mm. The incident angle between the second aerosol nozzle 23 and the sheet metal 4 is 45°. The flow rate of the second aerosol nozzle 23 is 1.2L / min. The coverage area of ​​the first aerosol nozzle 13 is 25.2mm². 2 The maximum force for the first tool head 11 in the roll forming process is 750N.

[0092] The specific process parameters for Example 1 are shown in Table 1 below:

[0093] Table 1 Specific process parameters of Example 1

[0094] In a specific embodiment 2, the following is adopted: Figures 1 to 4 The laser and aerosol co-control shaping equipment for robotic incremental forming forms L-shaped parts from martensitic steel sheet 4. During the processing, dual robots, a single tool head, and a dual-point laser are used to simultaneously and locally heat the bending area of ​​sheet 4, while dual aerosol nozzles are used to cool the forming area.

[0095] In this embodiment, the ultra-high strength steel has a tensile strength of 1700 MPa, a room temperature elongation of not less than 5%, and a thickness of 1.9 mm.

[0096] Specifically, similar to Embodiment 1, the ultra-high strength sheet 4 is clamped by the tooling fixture 3, and the sheet 4 is rolled and formed by the first tool head 11 according to the shape of the target part. During the forming process, the first laser 12 and the second laser 22 simultaneously heat the ultra-high strength sheet 4 locally to assist in the forming of the ultra-high strength steel sheet 4. At the same time, the first aerosol nozzle 13 and the second aerosol nozzle 23 play the role of cooling the bending area of ​​the sheet 4 in real time.

[0097] In step S30, the first tool head 11 and the first laser 12 move synchronously. The rolling rate of the first tool head 11 and the scanning rate of the first laser 12 are the same, both being 20 mm / s. The first robot 1 is simultaneously fixed with the first tool head 11, the first laser 12, and the first aerosol nozzle 13. The distance between the first laser 12 and the sheet metal 4 along the direction of the first laser 12 is 25 mm, the incident angle between the first laser 12 and the sheet metal 4 is 53°, and the power of the first laser 12 is 2000 W. The distance between the first aerosol nozzle 13 and the first laser 12 along the direction of the first laser 12 is 5 mm, the incident angle between the first aerosol nozzle 13 and the sheet metal 4 is 45°, the flow rate of the first aerosol nozzle 13 is 1.5 L / min, and the coverage area of ​​the first aerosol nozzle 13 is 36 mm². 2 A second laser 22 and a second aerosol nozzle 23 are fixed on the second robot 2. The second laser 22 is always perpendicular to the sheet metal 4, and the power of the second laser 22 is 1500W. The distance between the second aerosol nozzle 23 and the second laser 22 along the direction of the second laser 22 is 5mm. The incident angle between the second aerosol nozzle 23 and the sheet metal 4 is 45°. The flow rate of the second aerosol nozzle 23 is 2.0L / min. The coverage area of ​​the first aerosol nozzle 13 is 31.5mm². 2 The maximum force for the first tool head 11 in the roll forming process is 1150N.

[0098] The specific process parameters for Example 2 are shown in Table 2 below:

[0099] Table 2 Specific process parameters of Example 2

[0100]

[0101] In a specific embodiment 3, the following is adopted: Figures 5 to 8 The laser and aerosol co-control shaping equipment for robotic incremental forming forms L-shaped parts from martensitic steel sheet 4. During processing, dual robots, dual tool heads, and dual-point lasers are used to simultaneously and locally heat the bending area of ​​sheet 4, while dual aerosol nozzles are used to cool the forming area.

[0102] In this embodiment, the ultra-high strength steel has a tensile strength of 1700 MPa, a room temperature elongation of not less than 5%, and a thickness of 1.9 mm.

[0103] Specifically, the ultra-high strength sheet 4 is clamped by the tooling fixture 3, and the sheet 4 is rolled into shape according to the shape of the target part using the first tool head 11 (the first tool head 11 is used for rolling). During the forming process, the first laser 12 and the second laser 22 simultaneously heat the ultra-high strength sheet 4 locally. The second tool head 21 (the second tool head 21 is used for support) moves synchronously with the first tool head 11 to limit the displacement of the sheet 4 and assist in the forming of the ultra-high strength steel sheet 4. At the same time, the first aerosol nozzle 13 and the second aerosol nozzle 23 cool the bending area of ​​the sheet 4 in real time.

[0104] In step S30, the first tool head 11 and the first laser 12 move synchronously. The rolling rate of the first tool head 11 and the scanning rate of the first laser 12 are the same, both being 50 mm / s. The first robot 1 is simultaneously fixed with the first tool head 11, the first laser 12, and the first aerosol nozzle 13. The distance between the first laser 12 and the sheet metal 4 along the direction of the first laser 12 is 25 mm, the incident angle between the first laser 12 and the sheet metal 4 is 53°, and the power of the first laser 12 is 3500 W. The incident angle between the first aerosol nozzle 13 and the sheet metal 4 is 45°, the flow rate of the first aerosol nozzle 13 is 2.5 L / min, and the coverage area of ​​the first aerosol nozzle 13 is 45 mm². 2 The second robot 2 is equipped with a second tool head 21, a second laser 22, and a second aerosol nozzle 23. The distance between the second laser 22 and the sheet metal 4 along the direction of the second laser 22 is 25 mm, the incident angle between the second laser 22 and the sheet metal 4 is 53°, and the power of the second laser 22 is 2000W. The distance between the second aerosol nozzle 23 and the second laser 22 along the direction of the second laser 22 is 5 mm, the incident angle between the second aerosol nozzle 23 and the sheet metal 4 is 45°, the flow rate of the second aerosol nozzle 23 is 3.0 L / min, and the coverage area of ​​the first aerosol nozzle 13 is 21.2 mm². 2 The maximum force for the first tool head 11 in the roll forming process is 2000N.

[0105] The specific process parameters for Example 3 are shown in Table 3 below:

[0106] Table 3 Specific process parameters for Example 3

[0107]

[0108] To demonstrate the beneficial effects of this application, Comparative Example 1 is provided. Comparative Example 1 uses a conventional single-point laser-assisted robot roll forming process instead of the dual-point laser and aerosol co-process roll forming process in Example 1. Comparative Example 1 uses only one robot, and only one laser and one roll forming tool head are provided; no aerosol nozzles are used. In the single-point laser forming process of Comparative Example 1, the single laser source acts only on the outer surface of the metal sheet. The specific process parameters of Comparative Example 1 are shown in Table 4 below:

[0109] Table 4 Specific process parameters of Comparative Example 1

[0110]

[0111] The L-shaped steel parts prepared in Example 1 and Comparative Example 1 are compared and analyzed as follows to further illustrate the present invention.

[0112] 1. Formability Analysis

[0113] Figure 10 This is an L-shaped part manufactured using the single-point laser process in Comparative Example 1. (The part is made from...) Figure 10 It can be observed that the overall formability of the sheet metal is poor, and there is a very serious springback. In the actual forming process, the forming of all ten planned passes was not completed. During the third pass, due to the excessive springback of the sheet metal, the bending angle of some parts was too small, while the tool head had already rotated to 45°. As a result, the tool head collided with or seriously interfered with the sheet metal.

[0114] This situation occurs because a single-point laser cannot completely heat thicker plates. The outer surface of the area directly heated by the laser can reach a maximum temperature of 1200℃, exceeding the austenite transformation temperature. However, due to the thickness of the plate and the poor heat absorption capacity of ultra-high-strength steel, the middle and inner parts cannot be heated well. In addition, ultra-high-strength steel has high strength and poor plastic deformation capacity, so the springback is very severe when using single-point laser heating, to the point that the plate and the tool head collide with each other.

[0115] from Figure 12 As can be seen from the example, using the device provided in Example 1 ( Figures 1 to 4 The parts processed by the roll forming process have very little springback. Since the inner surface 42 of the sheet 4 is heated at the same time, even if the laser power of the inner surface 42 is relatively small, it can still fully heat the metal material, so that the temperature of the inner half of the sheet 4 is higher than that of a single-point laser, the softening is more complete, and the plastic deformation ability is stronger and the formability is better.

[0116] 2. Surface quality analysis after roll forming

[0117] Figure 11The diagram shows the surface of the part obtained by roll forming in Comparative Example 1. It can be seen that there are very obvious burn marks on the surface and particles formed by the metal melting into molten metal droplets and then solidifying at high temperature. It can be seen that the surface quality is poor and it is difficult to mass-produce or put into industrial production. Figure 10 As can be seen, the surface of the roll-formed part in Comparative Example 1 has relatively regular forming marks and traces of the heat-affected zone caused by laser heating. Figure 13 For sheet material 4, the equipment provided in Example 1 is used ( Figures 1 to 4 The photo of the inner surface 42 of the part obtained by the roll forming process shows that there is a clear laser heating mark on the inner surface 42, but the surface is very smooth and there is no trace of metal melting and then solidifying.

[0118] Because the dual-point laser heats both the inside and outside simultaneously, the temperature distribution of the sheet 4 along the thickness direction is completely different from that of the single-point laser. The laser on the inner surface 42 can provide effective heating to the inner half of the thicker sheet 4. Combined with the heating effect of the laser on the outer surface 41, the entire sheet 4 can be uniformly heated and softened along the thickness direction. When bending it with rollers, the entire bending area can produce plastic deformation, while the springback is small and there are no cracking or edge wavy problems.

[0119] 3. Forming force analysis during roll forming process

[0120] In Example 1, the forming force during the forming process under the dual-point laser process is 750N, while in Comparative Example 1, since only the outer surface is heated by a single laser, the forming force is 3000N. When only the outer surface of the sheet is heated by the laser, a very obvious temperature gradient distribution occurs along the thickness direction inside the sheet. The temperature distribution along the sheet thickness can be approximated by an exponential function; that is, the farther away from the outer surface of the sheet, the smaller the influence of the laser, and the closer the temperature is to room temperature. Because the sheet itself has high strength and is prone to severe springback if not fully softened, Comparative Example 1 shows severe springback and a large forming force.

[0121] When the inner and outer surfaces of sheet 4 are heated by a laser heat source at the same time, the laser heat source acting on the inner surface 42 of sheet 4 can greatly improve the problem of low material temperature near the inner surface 42. At the same time, the temperature distribution inside sheet 4 is no longer a gradient distribution. The higher temperature makes sheet 4 fully softened, and plastic deformation can be completed under a small force. Meanwhile, because the temperature of sheet 4 is high during deformation, there will be no large residual stress, and there will be no much stress release after cooling. Therefore, sheet 4 will not have a large springback, ensuring forming accuracy.

[0122] 4. Metallographic and Microhardness Analysis of the Bending Area of ​​Rolled Parts

[0123] To investigate the microstructure and microhardness of the bent parts obtained in Example 1 and Comparative Example 1, samples were taken from the bent parts of the parts obtained by the two processes and inlays were fabricated. Figure 14 The metallographic results at the bend of the part obtained in Comparative Example 1 are shown below. Figure 14 (a) Figure 14 (b) Figure 14 (c) Metallographic images of the outer, middle, and inner layers at the bend are shown respectively. It is clearly observed that the outer layer has a relatively smaller grain size. This is because the outer layer of the bend area is directly heated by the laser, reaching the austenite transformation temperature within 1 second, and then rapidly decreasing in temperature. The result is a large amount of fresh martensite in the outer layer, with a smaller grain size. However, for… Figure 14 (b) Figure 14 (c) Obviously, the grains are larger. This is because the temperature phases of the middle and inner layers are too different from those of the outer layer and are lower than the austenite transformation temperature. During the forming process, the temperature gradient experienced by the bending area is also lower than that of the outer layer which is directly heated by the laser. Figure 15 The metallographic results at the bending point of the part obtained in Example 1 are shown below. Figure 15 (a) Figure 15 (b) Figure 15 (c) are metallographic photographs of the outer, middle and inner layers at the bending point, respectively. It can be observed that the grain size is relatively uniform along the thickness direction of the sheet material 4, and there is no case of excessive difference in grain size. This indicates that the parts obtained by this process have better material uniformity in the thickness direction after forming and smaller differences in mechanical properties.

[0124] like Figure 16 As shown, the microhardness of the bent parts was tested using two different processes, namely Example 1 and Comparative Example 1. Figure 16 (a) The red line represents the microhardness test area outside the bending area. Figure 16 (a) The yellow line in the middle represents the microhardness test area inside the bending region. Meanwhile... Figure 16 (b) Figure 16 (c) The locations of microhardness measurements of the outer and inner layers of the bending area of ​​the part obtained in Example 1 are shown respectively. Figure 16 (d) Figure 16 (e) are the microhardness points of the outer and inner layers of the bending area of ​​the part obtained in Comparative Example 1, respectively. Figure 17 This is a comparison chart of the microhardness test results of the bending area of ​​the part obtained in Example 1. Figure 18 This is a comparison chart of the microhardness test results of the bent area of ​​the part obtained in Comparative Example 1. (The text abruptly ends here.) Figure 17It was observed that the microhardness of the middle and outer layers in the bending region was almost the same. Lower microhardness was observed on both sides of the bending center region, where the microhardness was highest. This is because the temperature of the heat-affected zone was low during laser heating, making it difficult to reach the austenite transformation temperature, resulting in a higher concentration of tempered martensite in this region. Figure 18 It can be observed that there is a large difference in microhardness between the outer and middle layers of the bending area. This is because when using the laser-assisted robot roll forming process in Comparative Example 1, the temperature of the inner layer of the sheet is too low, resulting in a large amount of tempered martensite. This leads to a significant decrease in microhardness compared to the directly heated area. Calculations show that the microhardness of the outer layer of the bending area is about 100% higher than that of the inner layer, resulting in a severe gradient distribution of mechanical properties, which is not conducive to the use and mechanical property characterization of this type of part.

[0125] To demonstrate the beneficial effects of this application, Comparative Example 2 is provided. Comparative Example 2 uses a conventional dual-point laser-assisted robot roll forming process instead of the dual-point laser and aerosol synergistic roll forming process in Example 3. Comparative Example 2 uses two robots, equipped with two lasers and two roll forming tool heads, but without aerosol nozzles. During the forming of ultra-high strength steel sheet using the dual-robot roll forming process of Comparative Example 2, no specific cooling device or cooling measures are used. The specific process parameters of Comparative Example 2 are shown in Table 5 below:

[0126] Table 5 Specific process parameters for Comparative Example 2

[0127]

[0128] The formability comparison analysis of the L-shaped steel parts prepared in Example 3 and Comparative Example 2 is conducted as follows to further illustrate the present invention.

[0129] like Figure 19 As shown in Comparative Example 2, when the sheet metal is simultaneously irradiated by two laser spots, the highest temperatures on both its inner and outer surfaces can reach above the austenite transformation temperature of ultra-high strength steel. Therefore, it can be seen from... Figure 19 (a) and Figure 19 (c) It can be seen that the grain sizes of the inner and outer layers within the bending area are very similar. Furthermore, due to the smaller spot size of the inner layer and the more concentrated laser energy, the temperature is also higher, resulting in a slightly smaller grain size in the inner layer compared to the outer layer, although the difference is limited. However, because the temperature difference between the inner and outer surfaces and the temperature of the middle layer of the sheet is too large, such as... Figure 19 As shown in (b), the grain size, composition and arrangement of the middle layer are significantly different from those of the outer and inner layers.

[0130] Figure 20 Metallographic images of different locations at the bending points of the parts obtained by the roll forming process performed using the equipment provided in Example 3 can be obtained from... Figure 20(a) Figure 20 (b) Figure 20 (c) It can be seen that the grain size is basically the same at different positions along the thickness direction in the formed area. This is because the temperature difference between the inner and outer surfaces of the sheet 4 and the unheated part inside can be reduced to a sufficiently small degree in a very short time, thus exhibiting the following characteristics. Figure 20 As shown, the grain size of plate 4 is relatively uniform along the thickness direction.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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 utility model subject matter.

Claims

1. A laser and aerosol co-control device for incremental forming in robots, characterized in that, include: A first robot and a second robot are respectively positioned on both sides of the sheet metal; the first robot and the second robot remain relatively stationary at all times; the first robot is fixedly equipped with a first tool head, a first laser, and a first aerosol nozzle, and the first tool head, the first laser, and the first aerosol nozzle remain relatively stationary at all times; the first laser and the first aerosol nozzle are respectively located on both sides of the first tool head; the second robot is fixedly equipped with a second laser and a second aerosol nozzle, and the second laser and the second aerosol nozzle remain relatively stationary at all times.

2. The laser and aerosol co-control shaping device for robotic incremental forming according to claim 1, characterized in that, The second aerosol nozzle is configured such that the area of ​​the aerosol it sprays is larger than the area of ​​the irradiated region of the laser emitted by the second laser.

3. The laser and aerosol co-control shaping device for robotic incremental forming according to claim 2, characterized in that, The area covered by the aerosol sprayed from the second aerosol nozzle is 1.5 to 5 times the area of ​​the irradiated area of ​​the laser emitted by the second laser.

4. The laser and aerosol co-control shaping device for robotic incremental forming according to claim 1, characterized in that, The first aerosol nozzle is configured such that the area of ​​the aerosol it sprays is larger than the area of ​​the irradiated region of the laser emitted by the first laser.

5. The laser and aerosol co-control shaping device for robotic incremental forming according to claim 4, characterized in that, The area covered by the aerosol sprayed from the first aerosol nozzle is 1.5 to 5 times the area of ​​the irradiated area of ​​the laser emitted by the first laser.

6. The laser and aerosol co-control shaping device for robotic incremental forming according to any one of claims 1-5, characterized in that, When the light spot of the first laser irradiates the surface of the sheet metal, it is rectangular, with a length of 4-10 mm and a width of 2 mm.

7. The laser and aerosol co-control shaping device for robotic incremental forming according to claim 1, characterized in that, When the light spot of the second laser irradiates the surface of the sheet metal, it is circular, and the radius of the circular light spot is 1~10mm.

8. The laser and aerosol co-control shaping device for robotic incremental forming according to claim 1, characterized in that, The equipment also includes tooling fixtures for fixing the sheet metal.

9. The laser and aerosol co-control shaping device for robotic incremental forming according to claim 8, characterized in that, The second robot is also fixedly equipped with a second tool head, which remains relatively stationary relative to the second laser at all times.

10. The laser and aerosol co-control shaping device for robotic incremental forming according to claim 9, characterized in that, The second laser and the second aerosol nozzle are located on both sides of the second tool head, respectively.

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