Process and device for ultrasonic / laser combined multi-scale integrated forming of special-shaped fins

Abstract

The application discloses a special-shaped fin ultrasonic / laser composite multi-scale integrated forming process method and device, and the method comprises the following steps: S1, pretreating a to-be-formed fin to obtain a to-be-processed fin; S2, preparing a functional surface micro-texture by installing a clamp with a finger interdigital transducer to conduct a surface acoustic wave in the process of laser scanning the fin; and S3, performing laser bending forming through a reversible clamp, and the specific processing comprises the following steps: 1) designing front and back surface scanning tracks according to the special-shaped fin structure; and 2) determining process parameters, discretizing different areas of a heating line, and adopting an energy regulation strategy to realize accurate forming. The application realizes multi-scale special-shaped fin integrated forming without secondary disassembly, and the obtained multi-scale special-shaped fin can improve the service performance of the micro-channel fin, such as enhancing heat and mass transfer, improving catalyst contact area and adhesion, and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal plate forming, and particularly relates to a special-shaped fin ultrasonic / laser composite multi-scale integrated forming process method and device. BACKGROUND

[0002] Fin structures (such as fuel cell bipolar plates, reactor flow channel plates, heat exchanger fins, etc.) are core components in emerging fields such as new energy vehicles, hydrogen energy equipment, and thermal management systems, and play key roles in heat and mass transfer, catalyst support, directional flow guiding, and structural support. Under the demand for high efficiency and high energy density, fin structures are developing towards miniaturization, special shape, and multi-scale, for example: high-efficiency heat exchanger fins use designs with surface micro-structure, micro-reactor flow channel plates use designs with different porosity structures for inlet and outlet flow channels, and fuel cell bipolar plates use designs with side protrusions for 3D flow channels.

[0003] The manufacturing of multi-scale fins usually involves texture forming and bending processes, and is usually processed independently in steps. Macroscopic flow channels are first formed by stamping, and then surface micro-texture is manufactured by surface texturing techniques such as electrochemical machining, electrical discharge machining, and abrasive air jet technology. Due to uneven stress and scale effects, traditional forming processes often result in problems such as springback and wrinkling, poor uniformity, and dimensional deviation. In addition, the design and manufacturing of special-shaped fins can result in higher mold costs and longer production cycles. Due to the complexity of the process, difficulty in forming, and many defects, the forming quality and yield of multi-scale fins are severely affected.

[0004] Laser manufacturing has the advantages of non-contact, high efficiency, greenness, and selective area. Laser melting is a scientific technology that improves the wear resistance and corrosion resistance of part surfaces and surface topography without changing the material properties. It can control both shape and properties. Laser bending forming technology is a non-die, high-flexibility bending forming technology. It has the characteristics of short production cycle, low manufacturing cost, and high quality of bent plates. This technology has been applied to plate forming since the 1980s. SUMMARY

[0005] In order to solve the technical problems of traditional multi-scale special-shaped fin forming process, such as complicated process, difficult forming, and many defects, in combination with the laser bending forming method, the sound field action of ultrasonic surface wave and the heat action of laser, the application provides a special-shaped fin ultrasonic / laser composite multi-scale integrated forming process method and device. The application forms a micro-melt pool by laser heating, and the stable high-frequency sound field is generated by the reversible fin clamp and conducted to the fin by the ultrasonic surface wave, and after the laser scanning is finished, the liquid oscillation melt pool is solidified to form regular micro-texture after air conduction; at the same time, after the texture forming, the scanning process and scanning parameters are changed, and the special-shaped fin is formed on the micro-texture surface by alternately changing the scanning on the front and back sides of the clamp along the designed path.

[0006] The technical scheme adopted by the application is:

[0007] A special-shaped fin ultrasonic / laser composite multi-scale integrated forming method, characterized in that it specifically comprises the following steps:

[0008] S1, pretreating the fin to be formed to obtain a fin to be processed;

[0009] S2, clamping the fin to be processed, and conducting the acoustic surface wave by the clamp provided with the interdigital transducer to prepare the functional surface micro-texture during the laser scanning of the fin;

[0010] S3, laser bending forming the fin by the reversible clamp;

[0011] S4, taking out the formed multi-scale special-shaped fin, line cutting the formed part, removing the clamping area, and performing alcohol cleaning to remove the coated carbon black layer, drying to obtain the processed fin and performing subsequent assembly work.

[0012] Further, in the step S1, the specific process of pretreating the fin to be formed is as follows: the fin to be formed is pretreated, the residual stress of the fin itself is removed by a heat treatment process, the fin after treatment is polished by sandpaper to remove surface oxides, and a carbon black layer is coated on the upper and lower surfaces of the fin, and the clamping area is pre-set and the scanning track is designed.

[0013] Further, the specific process of step S2 is as follows: turn on the ultrasonic generator and power amplifier, adjust the appropriate ultrasonic power, the ultrasonic generator generates a sound field, and the signal is amplified through the power amplifier and transmitted to the interdigital transducer on the loading fixture, so that the fixture surface where the interdigital transducer is located generates high-frequency vibration to form a stable ultrasonic surface wave, and the ultrasonic surface wave is conducted to the fin through the fixture; the laser texturing process parameters are set in the computer at the same time, and the surface is scanned, and a micro-melt pool is generated in the scanning area of the fin during the laser action due to the heat input of the laser. The melt pool oscillates regularly under the action of the acoustic surface, and after the laser action is over, the oscillating micro-melt pool exchanges heat with the air due to the sudden temperature drop, and solidifies to form a stable regular surface micro-texture.

[0014] Further, in step S3, the specific process of laser bending forming by the reversible fixture is as follows:

[0015] S31, according to the structure of the special-shaped fin, the front and back scanning tracks are designed by computer;

[0016] S32, determine the process parameters, discretize different areas of the heating line, adopt an energy control strategy, and realize accurate forming.

[0017] Further, in step S1, the fin material used is a sub-millimeter thick 304 stainless steel sheet, and at the same time, the width of the metal sheet should be less than the width of the fixture, and the length should be within the range of the fin's bendable range. The length-width ratio of the processing area of the metal sheet should be kept within 1-2 to ensure that the metal sheet can be bent; the heat treatment temperature is 400-550℃, the furnace is heated to the temperature, the holding time is 2-4h, and the furnace is cooled; the scanning track is preset as a center-symmetric hyperbolic spline curve.

[0018] Further, in step S2, in order to control the additional distortion of the fin, the laser heat input needs to be controlled, the laser power is 200-300W, the laser diameter is 125-200μm, the scanning speed is 1500-2000mm / s, and the single scanning; the ultrasonic power ratio is 30-40%, and the ultrasonic frequency is 31.84kHz.

[0019] Further, in step S3, the laser power used is 150-250W, the laser diameter is 125-200μm, the scanning speed is 70-150mm / s, the scanning frequency is 10-100 times, and the scanning process is segmented to reduce the heat accumulation phenomenon at the end of the scanning line and reduce the surface distortion of the formed sheet.

[0020] Further, in the scanning process, the single-channel length S scanning line is equally divided into eight segments, and the speed is adjusted respectively.

[0021] Further, the finished fin is processed for cleaning, cutting, assembling holes and other post-processing and subsequent assembly work.

[0022] The device is characterized in that it comprises a loading clamp, a galvanometer laser and an ultrasonic device, the galvanometer laser transmits laser light through a galvanometer head; the ultrasonic device comprises an ultrasonic generator and a power amplifier, the loading clamp has a clamp for clamping a fin to be formed, and the clamp is automatically flipped through a flipping mechanism; a interdigital transducer is arranged on one end face of the clamp; the ultrasonic generator is connected with the interdigital transducer through the power amplifier; the laser mechanism is located above the fin to be formed, and the surface of the fin to be formed is always parallel to the workbench surface and located at the focal point of the galvanometer laser.

[0023] Further, the flipping mechanism comprises a motor, a transmission belt and a controller, the transmission belt is sleeved between the driving end of the motor and the fixed end of the loading clamp, for transmitting the rotary power of the motor to the loading clamp, the controller is connected to the motor through an electric signal, for controlling the start and stop of the motor and adjusting the rotating speed of the loading clamp; the loading clamp and the motor are fixedly installed on the workbench surface.

[0024] Compared with the prior art, the beneficial effects of the present application are embodied in:

[0025] 1. The process of the present application is simple, different from the traditional two-step forming method, can realize the integrated forming of multi-scale special-shaped fins, and only needs to be clamped once, improves the production efficiency, and can realize certain economic and social benefits.

[0026] 2. The surface texture after forming has high performance, and the synchronous coupling effect of the surface acoustic wave and the laser can realize the wave-shaped fusion morphology, which can increase the contact area of the subsequent catalyst or other coating materials and also improve the heat exchange efficiency in the reaction process, thereby having better application performance.

[0027] 3. The special-shaped part forming of the present application is more accurate, when the laser bending forming technology is adopted, the consistency of the scanning position accuracy before and after flipping can be ensured through the quantitative design of the flipping clamp and the scanning line process parameters, the degree of surface distortion in the scanning process is reduced, thereby further improving the forming accuracy of the special-shaped part. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the overall idea diagram of the special-shaped fin ultrasonic / laser composite multi-scale integrated forming of the present application;

[0029] Figure 2a is a schematic diagram of the special-shaped fin ultrasonic / laser composite multi-scale integrated forming device of the present applicationFigure 1 ;

[0030] Figure 2b is a schematic diagram of an ultrasonic / laser composite multi-scale integrated forming device for a special-shaped fin of the present application;

[0031] Figure 3 is a schematic diagram of a scanning path planning for a special-shaped part of the present application;

[0032] Figure 4 is a schematic diagram of eight-segment scanning variable speed regulation of the present application;

[0033] Figure 5 is a schematic diagram of laser forward scanning bending for a special-shaped fin of the present application;

[0034] Figure 6 is a schematic diagram of laser reverse scanning bending for a special-shaped fin of the present application. DETAILED DESCRIPTION

[0035] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the embodiments of the present application, and are not intended to limit the embodiments of the present application.

[0036] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0037] The present application will be described in detail below with reference to the accompanying drawings and in combination with exemplary embodiments.

[0038] Embodiment 1

[0039] In this embodiment, the fin 1 to be processed is a 304 stainless steel fin with a size of 65x30x0.4mm (lengthxwidthxthickness).

[0040] Referring to Figures 1 to 6 , a special-shaped fin ultrasonic / laser composite multi-scale integrated forming method of the present application includes the following steps:

[0041] S1, clean, dry and other pretreatments are performed on the fin to be formed, heat treated at 450℃, loaded into the furnace, the holding time is 3h, cooled with the furnace, and the residual stress of the fin itself is removed. The treated fin is polished by 400 mesh sandpaper to remove the surface oxide layer, and a carbon black layer is coated on the upper and lower surfaces of the fin, and a clamping width of 10mm is reserved on the length. The scanning trajectory as shown in Figure 3 is designed on the computer, wherein the solid line and the dashed line are the trajectories on both sides of the fin;

[0042] S2, the fin after path planning is clamped to the clamp, the level instrument is used to ensure that the fin surface is horizontal to the workbench, and the fin processing surface is located at the focal point of the galvanometer laser. Turn on the ultrasonic generator and power amplifier, adjust the ultrasonic power ratio to 30%; At the same time, set the laser texturing process parameters and the scanning area of the surface texture in the computer (for example, set the laser power to 200 W, the scanning speed to 1500 mm / s, and the spot diameter to 0.125 mm), when the surface of the fin produces stable high-frequency vibration, the surface is scanned, and a single scan is performed until the scanning is completed, and the molten pool is solidified to form a stable and regular surface micro-texture;

[0043] S3, on the fin after surface texturing, the scanning path is drawn in advance by the computer as shown in Figure 3 , and is scanned in turn from right to left. In order to suppress the surface distortion in the scanning process, the scanning lines with a single channel length of S are equally divided into eight segments, and the speed is adjusted respectively, as shown in Figure 4 . The laser parameters are adjusted as follows: the laser power is 250 W, the spot diameter is 0.125 mm, the scanning times are 15, and the scanning process is as shown in Figure 5 . When reverse forming, the clamp is rotated 180° towards the fixed direction, and the scanning along the planned path is continued, as shown in Figure 6 . Before and after the clamp is turned over, the surface of the fin is always parallel to the workbench surface and located at the focal point.

[0044] S4, the formed multi-scale special-shaped fin is taken out, the formed part is wire cut, the clamping area is removed, and alcohol cleaning is performed, the coated carbon black layer is removed, and drying is performed, and subsequent assembly work is performed.

[0045] According to Example 1, the special-shaped fin structure in the form of a hyperbolic spline curve which is centrally symmetrical can be ultrasonic / laser composite multi-scale integrated formed.

[0046] Example 2

[0047] Referring to Figure 1 and FIG. 2, the special-shaped fin ultrasonic / laser composite multi-scale integrated forming device of the application comprises a loading clamp 2, a galvanometer laser 4 and an ultrasonic device, the galvanometer laser transmits laser through a galvanometer head 401; the ultrasonic device comprises an ultrasonic generator 201 and a power amplifier 202, the loading clamp 2 has a clamp for clamping a fin to be formed 1, and the clamp is automatically turned over through a turning mechanism; a interdigital transducer 203 is arranged on one end face of the clamp; the ultrasonic generator 201 is connected with the interdigital transducer 203 through the power amplifier 202; the galvanometer laser 4 is located above the fin to be formed 1, and the surface of the fin to be formed 1 is always parallel to the workbench surface and located at the focal point of the galvanometer laser 4.

[0048] The clamp is a piezoelectric substrate plate, and the material is a piezoelectric crystal or a piezoelectric ceramic.

[0049] The loading clamp 2 can realize 360° free overturning. The interdigital transducer 203 generates high-frequency vibration through the ultrasonic generator 201 and the power amplifier 202, and transmits the high-frequency vibration to the fin 1 through the loading clamp 2, so that a stable surface wave 5 is formed on the fin. The micro-melt pool formed by the action of the galvanometer laser 4 oscillates 301 under the action of the surface wave 5, and exchanges heat with the air after the laser sweeps, and solidification forms the texture 3.

[0050] The overturning mechanism includes a motor 204, a transmission belt 205 and a controller 206. The transmission belt 205 is sleeved between the driving end of the motor 204 and the fixed end of the loading clamp 2. The controller 206 is signal connected with the motor 204, and is used for control of start / stop and speed adjustment of the loading clamp 2. The loading clamp 2 and the motor 204 are fixed on the workbench.

[0051] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0052] In addition, the terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0053] In the present application, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected or in communication with each other; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0054] In the present application, unless otherwise explicitly specified and limited, a first feature is "on" or "under" a second feature can mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature is "over", "above" and "on top of" the second feature can mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. The first feature is "under", "below" and "underneath" the second feature can mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is horizontally lower than the second feature.

[0055] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. The illustrative description of the above terms in the present specification does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0056] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and the person skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A method for ultrasonic / laser hybrid multi-scale integrated forming of profiled fins, characterized in that, Specifically comprising the following steps: S1, pretreating the to-be-shaped fin to obtain a to-be-processed fin; S2, clamping the to-be-processed fin, and conducting an acoustic surface wave through a clamp provided with a finger transducer in the process of laser scanning the fin to prepare a functional surface micro-texture; S3, laser bending forming the fin through a reversible clamp; S4, taking out the shaped multi-scale special-shaped fin, performing wire cutting on the shaped part to remove the clamping area, and performing alcohol cleaning to remove the coated carbon black layer, drying to obtain the processed fin and performing subsequent assembly work; The specific process of step S2 is as follows: turn on the ultrasonic generator and power amplifier, adjust the appropriate ultrasonic power, the ultrasonic generator generates an acoustic field, and the signal is amplified through the power amplifier and transmitted to the finger transducer on the loading clamp, so that the clamp surface where the finger transducer is located generates high-frequency vibration to form a stable ultrasonic surface wave, and the ultrasonic surface wave is transmitted to the fin through the clamp; set the laser texturing process parameters in the computer at the same time, and perform surface scanning, during the laser action, the scanning area of the fin generates a micro-melt pool due to the heat input of the laser, the melt pool generates regular oscillation under the action of the acoustic surface, and after the laser action ends, the oscillating micro-melt pool exchanges heat with the air due to the sudden temperature drop, and solidifies to form a stable regular surface micro-texture; In step S3, the specific process of laser bending forming through a reversible clamp is as follows: S31, according to the structure of the special-shaped fin, design the front and back surface scanning tracks through a computer; S32, determine the process parameters, discretize different areas of the heating wire, adopt an energy control strategy, and realize accurate forming.

2. The ultrasonic / laser composite multi-scale integrated forming method for special-shaped fins according to claim 1, characterized in that: In step S1, the specific process of pretreating the to-be-shaped fin is as follows: pretreat the to-be-shaped fin, remove the surface oxides of the fin through a heat treatment process, coat a carbon black layer on the upper and lower surfaces of the fin, and pre-set the clamping area and design the scanning track.

3. The method of claim 1, wherein the method is a method of ultrasonic / laser hybrid multi-scale integrated forming of a profiled fin, and the method comprises the steps of: In step S1, the selected fin material is a sub-millimeter 304 stainless steel metal plate, the width of the metal plate should be less than the width of the clamp, and the length should be within the bendable range of the fin, the length-width ratio of the metal plate processing area should be kept within 1-2 to ensure that the metal plate can be bent; the heat treatment temperature is 400-550 DEG C, the furnace is heated to the temperature, the holding time is 2-4 h, and the furnace is cooled down; the scanning track is preset as a center-symmetric hyperbolic spline curve.

4. The ultrasonic / laser composite multi-scale integrated forming method for special-shaped fins according to claim 1, characterized in that: In step S2, to control the additional distortion of the fin, the laser heat input needs to be controlled, the laser power is 200-300 W, the laser diameter is 125-200 μm, the scanning speed is 1500-2000 mm / s, and the ultrasonic power ratio is 30-40%, and the ultrasonic frequency is 31.84 kHz.

5. The ultrasonic / laser composite multi-scale integrated forming method for special-shaped fins according to claim 1, characterized in that: The laser power used in the step S3 is 150-250 W, the laser diameter is 125-200 μm, the scanning speed is 70-150 mm / s, and the scanning times are 10-100, and the scanning process is segmented and variable speed processing is performed to slow down the heat accumulation at the end of the scanning line and reduce the surface distortion of the formed sheet.

6. The method of claim 5, wherein the method is a method of ultrasonic / laser hybrid multi-scale integrated forming of a profiled fin, and the method comprises the steps of: The single-channel length S of the scanning line is equally divided into eight segments during the scanning process, and the speed is adjusted respectively.

7. The apparatus for a profiled fin ultrasonic / laser hybrid multi-scale integrated forming method of claim 1, wherein The device comprises a loading clamp (2), a galvanometer laser (4) and an ultrasonic device, the galvanometer laser transmits laser through a galvanometer head (401), the ultrasonic device comprises an ultrasonic generator (201) and a power amplifier (202), the loading clamp (2) has a clamp for clamping a to-be-formed fin (1), and the clamp is automatically flipped through a flipping mechanism; a interdigital transducer (203) is arranged on one end surface of the clamp; the ultrasonic generator (201) is connected with the interdigital transducer (203) through the power amplifier (202); the galvanometer laser (4) is located above the to-be-formed fin (1), and the surface of the to-be-formed fin (1) is always parallel to the workbench surface and located at the focal point of the galvanometer laser (4).

8. The apparatus of claim 7, wherein, The flipping mechanism comprises a motor (204), a transmission belt (205) and a controller (206), the transmission belt (205) is sleeved between the driving end of the motor (204) and the fixed end of the loading clamp (2) for transmitting the rotary power of the motor (204) to the loading clamp (2), the controller (206) is connected to the motor (204) through an electric signal for controlling the start and stop of the motor (204) and adjusting the rotating speed of the loading clamp (2); the loading clamp (2) and the motor (204) are fixedly installed on the workbench surface.

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