Shape-property regulation and control method and device for ultrasonic rolling-combined selective laser melting

Abstract

A shape-property regulation and control method for ultrasonic rolling-combined selective laser melting, comprising the following steps: S1, establishing a three-dimensional model for a component to be processed, and setting printing process parameters; S2, after filling nitrogen into a forming cavity (15) to reduce the oxygen content to a preset value, a forming substrate (16) descending, and a powder substrate (19) ascending; by means of a scraper (7), laying powder onto the forming substrate (16) from the powder substrate (19) and recycling redundant powder; after laying is completed, melting the powder by means of a laser galvanometer to form a solid layer; and repeating same for multiple times; S3, performing ultrasonic rolling on the surface of the solid layer; S4, repeating steps S2 and S3 until said component is formed; and S5, performing ultrasonic rolling on the surface of the formed component, so as to obtain a solid component. The method can eliminate metallurgical defects generated during printing, improve the mechanical properties of the interior and the surfaces of components, and improve the practicability of selective laser melting devices.

Description

A method and device for controlling the shape of ultrasonic rolling combined with laser selective melting Technical Field

[0001] The present invention belongs to the technical field of additive manufacturing, and in particular relates to a method and device for controlling the shape of ultrasonic rolling combined with laser selective melting. Background Art

[0002] After more than two decades of development, metal additive manufacturing has become one of the fastest-growing and most promising technologies in advanced manufacturing. It not only overcomes many of the inherent limitations of traditional production but also significantly shortens design and manufacturing time and reduces material waste. However, it also has disadvantages such as high cost, potentially long processing times, and expensive powder feedstock.

[0003] Selective laser melting technology uses computer software to control a high-energy laser beam, selectively melting metal powder in a powder bed along a pre-set path in a protective atmosphere, achieving layer-by-layer printing and stacking. Due to the rapid speed of the laser, the molten metal solidifies rapidly, inhibiting grain growth and the precipitation of alloying elements. Combined with the disturbing effect of the Marangoni flow in the molten pool, the material's microstructure is significantly refined, thereby increasing the material's strength and toughness. However, rapid thermal cycling can produce sharp thermal gradients and possible metastable physical and chemical states, resulting in undesirable metallurgical defects, which is a key issue for the widespread application of all current metal additive manufacturing.

[0004] Summary of the Invention

[0005] The purpose of the present invention is to provide a method and device for controlling the properties of ultrasonic rolling combined with laser selective melting to solve the above-mentioned problems, thereby eliminating metallurgical defects generated during printing, improving the mechanical properties of the interior and surface of parts, and increasing the practicality of the laser selective melting device.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A method for controlling the shape of ultrasonic rolling combined with laser selective melting comprises the following steps:

[0008] S1. Create a three-dimensional model of the component to be processed and set the printing process parameters;

[0009] S2. After nitrogen is filled into the forming cavity to reduce the oxygen content to a preset value, the forming substrate is lowered and the powder substrate is raised. The powder is spread from the powder substrate to the forming substrate by a scraper, and the excess powder is recovered. After the spreading is completed, the powder is melted by a laser galvanometer to form a solid layer. This cycle is repeated several times.

[0010] S3, performing ultrasonic rolling on the surface of the solid layer;

[0011] S4, looping steps S2 and S3 until the component is formed, and then ending the loop;

[0012] S5. Perform ultrasonic rolling on the surface of the formed component to obtain a solid component.

[0013] Preferably, in step S1, a three-dimensional model is formed on the component to be processed, the three-dimensional model is sliced ​​by slicing software, and the slice data and process parameters are input into a computer control center.

[0014] Preferably, in step S2, high-purity nitrogen is introduced into the forming cavity, and after the oxygen content is reduced to a preset value, the printing program is started, the forming substrate descends to a fixed height H, and the powder substrate rises to a height of 2H. The scraper spreads the powder from the powder substrate onto the forming substrate and collects excess powder into a recovery cylinder. After the powder is laid, the laser galvanometer performs laser selective melting on the powder on the forming substrate to obtain a solid layer. The cycle is repeated N times, and the printing program is paused after N solid layers are generated. The number of solid layers depends on the depth of the layer affected by the residual stress of ultrasonic rolling.

[0015] Preferably, in step S3, an ultrasonic generator is started to perform ultrasonic rolling on the surface of the solid layer to prepare the required component, and the component is reset after the processing is completed.

[0016] 5. A device for implementing the shape control method of ultrasonic rolling combined with laser selective melting according to any one of claims 1 to 4, comprising an outer shell body, the forming cavity is opened inside the outer shell body, a laser galvanometer is fixedly connected to the top wall of the forming cavity, an optical lens is fixedly connected to the bottom surface of the laser galvanometer, an ultrasonic rolling assembly is provided in the forming cavity, the optical lens and the ultrasonic rolling assembly are located above the forming substrate, the scraper is slidably connected in the forming cavity, the bottom end of the scraper is in sliding contact with the bottom wall of the forming cavity, the scraper is located above the forming substrate and the powder substrate, and the forming substrate and the powder substrate are both slidably connected in the powder portion;

[0017] The laser galvanometer and ultrasonic rolling assembly are electrically connected to a computer control center.

[0018] Preferably, the powder part includes a powder cylinder, a forming cylinder, and a recovery cylinder fixedly connected to the inside of the outer casing. The powder cylinder, forming cylinder, and recovery cylinder are arranged in sequence along the powder laying direction. The forming base plate is slidably connected to the inner side wall of the forming cylinder. The powder base plate is slidably connected to the inner side wall of the powder cylinder. The bottom ends of the powder base plate and the forming base plate are fixedly connected to one end of a transmission rod, and the other end of the transmission rod is transmission-connected to the lifting part.

[0019] Preferably, the lifting part includes a second slider fixedly connected to the bottom end of the transmission rod, the second slider is connected to the second servo motor through a second screw, the second slider is slidably connected to the guide rail, and the guide rail is fixedly connected to the inner wall of the outer shell box.

[0020] Preferably, one end of the scraper is fixedly connected to a first slider, the first slider is connected to the first servo motor and the first screw transmission, the first slider is slidably connected to the slide rail, and the slide rail is fixedly connected to the side wall of the forming cavity.

[0021] Preferably, the ultrasonic rolling assembly includes an ultrasonic generator and a robotic arm fixedly connected to the side wall of the forming cavity, the ultrasonic generator is electrically connected to the computer control center, the end of the robotic arm is fixedly connected to a transducer, the transducer is electrically connected to the computer control center, the bottom end of the transducer is threadedly connected to a variable amplitude rod, the end of the variable amplitude rod away from the transducer is fixedly connected to a rolling head, and the rolling head is arranged correspondingly above and below the forming substrate.

[0022] Compared with the prior art, the present invention has the following advantages and technical effects:

[0023] 1. The present invention repeats the laser selective melting and ultrasonic rolling several times. Through the layer-by-layer ultrasonic rolling texturing treatment, plastic deformation can be generated to eliminate internal stress and metallurgical defects, and the laser absorption rate can be improved, and the interlayer bonding strength can be enhanced to obtain high-performance additive manufacturing formed components.

[0024] 2. Ultrasonic rolling finishing treatment can not only obtain a smooth surface, but also effectively improve the mechanical properties of the surface, avoiding tedious post-processing methods.

[0025] 3. The entire process is fully automated, which reduces manpower waste, improves work efficiency, ensures the user's own safety, and improves the overall mechanical properties of additively manufactured components. The overall economy, safety, work efficiency, accuracy and practicality are high. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work.

[0027] FIG1 is a schematic diagram of the overall structure of the present invention;

[0028] FIG2 is a schematic structural diagram of an ultrasonic rolling assembly;

[0029] FIG3 is a schematic diagram of the process of the present invention;

[0030] FIG4 is a surface morphology of a formed component obtained by using the prior art;

[0031] FIG5 shows the surface morphology of the molded component obtained by the present invention.

[0032] Among them, 1. outer shell; 2. laser galvanometer; 3. optical lens; 4. transducer; 5. amplitude transformer; 6. rolling head; 7. scraper; 8. computer control center; 9. powder cylinder; 10. guide rail; 11. recovery cylinder; 12. forming cylinder; 13. ultrasonic generator; 14. robotic arm; 15. forming cavity; 16. forming substrate; 17. slide rail; 18. first slider; 19. powder substrate; 20. transmission rod; 21. second slider. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] 1 to 3 , the present invention provides a method for controlling the shape of ultrasonic rolling combined with laser selective melting, comprising the following steps:

[0036] S1. Create a three-dimensional model of the component to be processed and set the printing process parameters;

[0037] S2. After nitrogen is filled into the forming cavity 15 to reduce the oxygen content to a preset value, the forming substrate 16 descends and the powder substrate 19 ascends. The scraper 7 spreads the powder from the powder substrate 19 onto the forming substrate 16, and the excess powder is recovered. After the laying is completed, the laser galvanometer 2 melts the powder to form a solid layer. This cycle is repeated several times.

[0038] S3, performing ultrasonic rolling on the surface of the solid layer;

[0039] S4, looping steps S2 and S3 until the component is formed, and then ending the loop;

[0040] S5. Perform ultrasonic rolling on the surface of the formed component to obtain a solid component.

[0041] To further optimize the solution, in step S1 , a three-dimensional model is formed on the component to be processed, the three-dimensional model is sliced ​​by slicing software, and the slice data and process parameters are input into the computer control center 8 .

[0042] To further optimize the solution, in step S2, high-purity nitrogen is introduced into the forming cavity 15. After the oxygen content is reduced to a preset value, the printing program is started, the forming substrate 16 descends to a fixed height H, and the powder substrate 19 rises to a height of 2H. The scraper 7 spreads the powder from the powder substrate 19 onto the forming substrate 16 and collects the excess powder into the recovery cylinder 11. After the powder is laid, the laser galvanometer 2 performs laser selective melting on the powder on the forming substrate 16 to obtain a solid layer. The cycle is repeated N times. After N solid layers are generated, the printing program is paused. The number of solid layers depends on the depth of the layer affected by the residual stress of ultrasonic rolling.

[0043] To further optimize the solution, in step S3, the ultrasonic generator 13 is started to perform ultrasonic rolling on the surface of the solid layer to prepare the required components, and the components are reset after the processing is completed.

[0044] In step S1, a three-dimensional model of the component to be processed is performed on a computer, and the model is imported into a slicing software for slicing to obtain an STL format file. The laser selective melting and ultrasonic rolling process parameters of the material to be printed are set according to processing experience, and the laser selective melting printing program and ultrasonic rolling processing program are compiled and uniformly input into the computer control center 8;

[0045] In step S3, ultrasonic rolling is performed on the surface of the forming substrate 16 to prepare a periodic micro-textured surface. The textured surface can provide better interlayer bonding performance and improve the density and mechanical properties of the first N layers of formed entities. The micro-textured surface morphology can be grooves, circular pits, V-shaped pits, and grids. The average peak-to-valley height of the micro-texture is 2-30 μm, and the texture width is 50-200 μm.

[0046] In step S5, ultrasonic rolling is performed again on the surface of the formed component to prepare a smooth metal surface, thereby obtaining a solid component with excellent surface accuracy and overall performance.

[0047] In step S2, the powder is a spherical powder specially used for laser selective melting, which can be aluminum alloy powder, titanium alloy powder, or nickel-based alloy powder. The powder particle size is 15-53 μm, and it has good fluidity and high apparent density.

[0048] The laser energy of the laser galvanometer 2 is 100-500W, the scanning speed is 200-2000mm / s, the layer thickness is 30-50μm, the scanning spacing is 80-100μm, and the island scanning strategy is adopted.

[0049] In step S3, the ultrasonic rolling head may be a ball, a roller, a wheel, etc., and the ultrasonic rolling process parameters are: static pressure 200-1000N, amplitude 5-30μm, and output frequency 18-22KHz.

[0050] 4-5 , the ultrasonic rolling finishing treatment of the present invention can reduce the surface roughness to Ra 0.5 μm, so that the formed component has higher surface accuracy and mechanical stability.

[0051] A device for a shape property control method of ultrasonic rolling combined with laser selective melting includes an outer shell body 1, a forming cavity 15 is opened inside the outer shell body 1, a laser galvanometer 2 is fixedly connected to the top wall of the forming cavity 15, an optical lens 3 is fixedly connected to the bottom surface of the laser galvanometer 2, an ultrasonic rolling assembly is provided in the forming cavity 15, the optical lens 3 and the ultrasonic rolling assembly are located above a forming substrate 16, a scraper 7 is slidably connected in the forming cavity 15, the bottom end of the scraper 7 is in sliding contact with the bottom wall of the forming cavity 15, the scraper 7 is located above the forming substrate 16 and the powder substrate 19, and the forming substrate 16 and the powder substrate 19 are both slidably connected in the powder portion;

[0052] The laser galvanometer 2 , the ultrasonic rolling assembly and the computer control center 8 are electrically connected.

[0053] A further optimized solution is provided, in which the powder part includes a powder cylinder 9, a forming cylinder 12, and a recovery cylinder 11 fixedly connected to the inside of the outer casing 1. The powder cylinder 9, the forming cylinder 12, and the recovery cylinder 11 are arranged in sequence along the powder spreading direction. The forming base plate 16 is slidably connected to the inner wall of the forming cylinder 12, and the powder base plate 19 is slidably connected to the inner wall of the powder cylinder 9. The bottom ends of the powder base plate 19 and the forming base plate 16 are fixedly connected to one end of a transmission rod 20, and the other end of the transmission rod 20 is transmission-connected to the lifting part.

[0054] To further optimize the solution, the lifting part includes a second slider 21 fixedly connected to the bottom end of the transmission rod 20, the second slider 21 is connected to the second servo motor through a second lead screw, the second slider 21 is slidably connected to the guide rail 10, and the guide rail 10 is fixedly connected to the inner wall of the outer shell box 1.

[0055] To further optimize the solution, one end of the scraper 7 is fixedly connected to a first slider 18, the first slider 18 is connected through a first servo motor and a first lead screw transmission, the first slider 18 is slidably connected to a slide rail 17, and the slide rail 17 is fixedly connected to the side wall of the forming cavity 15.

[0056] The computer control center 8 controls the scraper 7 to complete a powder spreading action. The purpose of spreading powder is first to detect whether the forming cylinder 12 is zeroed, and secondly to spread the powder in the powder cylinder flat and even.

[0057] Further optimization scheme, the ultrasonic rolling assembly includes an ultrasonic generator 13 and a robotic arm 14 fixedly connected to the side wall of the forming cavity 15, the ultrasonic generator 13 is electrically connected to the computer control center 8, the end of the robotic arm 14 is fixedly connected to the transducer 4, the transducer 4 is electrically connected to the computer control center 8, the bottom end of the transducer 4 is threadedly connected to the amplitude rod 5, the end of the amplitude rod 5 away from the transducer 4 is fixedly connected to the rolling head 6, and the rolling head 6 is arranged correspondingly above and below the forming substrate 16.

[0058] The working process of the present invention is as follows:

[0059] A three-dimensional model of the part to be processed is established, and the CAD three-dimensional model of the part to be processed is pre-processed through slicing software, including slicing, repairing, supporting, and layout on the forming substrate 16, using 200W laser energy, 1000mm / s scanning speed, 80μm scanning spacing and 30μm layer thickness; then 25 layers are selected as units for slicing data packaging, and the movement parameters of the robot arm 14 and the parameters of the ultrasonic rolling equipment are added to the packaged data, including static pressures of 800N and 200N, amplitude of 20μm, output frequency of 20KHz and bow-shaped path planning. After completion, the STL file is imported into the computer control center 8 of the laser selective melting equipment.

[0060] Turn on the power of the laser selective melting device, control the powder substrate 19 to descend to a depth of 2-2.5 times the height of the part to be formed, fill the powder cylinder 9 with metal powder, and spread the powder flat, then adjust the forming substrate 16 to be level with the bottom of the forming cavity 15, and complete a powder spreading action through the computer control center 8. The purpose of powder spreading is first to detect whether the forming substrate 16 is zeroed, and secondly to spread the powder in the powder cylinder flat and even. When the forming substrate 16 is covered with a thin and even layer of metal powder, the zeroing is completed, the warehouse door is closed, and the gas circulation purification system is turned on to perform the deoxygenation procedure. The forming cavity 15 is equipped with a sensor, and the oxygen content is displayed on the computer panel in real time. The vacuum device draws the forming cavity 15 into a low pressure state, and then the air supply device fills the forming cavity 15 with helium, and the vacuum device is started again. Repeat this cycle until the oxygen content in the forming cavity 15 is lower than 800ppm before the processing can proceed.

[0061] First, the computer control center 8 controls the powder substrate 19 to rise 60μm, and at the same time the forming substrate 16 drops 30μm, then the scraper 7 moves at a constant speed from right to left to the rightmost side, and evenly spreads the metal powder of the powder substrate 19 above the plane onto the forming substrate 16, and finally the scraper 7 returns to the rightmost end to complete a powder spreading, and then the metal powder is sintered into a layer of entity by laser, and its surface morphology is shown in the first process in Figure 3. After each layer is formed, the powder is spread once, and this cycle continues. After 25 layers of powder are formed, the powder spreading system and the laser galvanometer 2 stop working, and the ultrasonic rolling device starts working. The computer control center 8 controls the robot arm 14 to drive the ultrasonic rolling device from the leftmost end of the forming cavity 15 according to the processing data information. The rolling device moves to the top of the forming substrate 16 to complete the given processing path, and then performs ultrasonic rolling surface texturing treatment to obtain periodic transverse grooves on the surface of the processed part, as shown in the second process in Figure 3. After the ultrasonic rolling surface texturing treatment is completed, the robot arm 14 drives the ultrasonic rolling device to return to the initial position to complete one ultrasonic rolling. The laser processing and ultrasonic rolling processing processes are repeated in this way until the entire processing process is completed. After all the physical parts are printed, ultrasonic rolling finishing treatment is performed, as shown in the fourth process in Figure 3, to obtain a physical part with excellent overall performance and surface performance. This process method largely solves the defects of low strength, voids, cracks, etc. of laser selective melting parts. High-strength and smooth-surface parts can be obtained. In addition, the ultrasonic rolling process of the internal texture of the part can obtain periodic transverse and longitudinal grooves, which can reduce the reflectivity of the metal surface and improve the metal's absorption rate of laser and the interlayer bonding strength.

[0062] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0063] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for controlling the shape of ultrasonic rolling combined with laser selective melting, characterized in that: The following steps are involved: S1. Establish a three-dimensional model of the component to be processed and set the printing process parameters; S2, after nitrogen is filled into the forming cavity (15) to reduce the oxygen content to a preset value, the forming substrate (16) is lowered, the powder substrate (19) is raised, the powder is spread from the powder substrate (19) to the forming substrate (16) by a scraper (7), and the excess powder is recovered. After the spreading is completed, the powder is melted by a laser galvanometer (2) to form a solid layer, and the cycle is repeated several times; S3, performing ultrasonic rolling on the surface of the solid layer; S4, looping steps S2 and S3 until the component is formed, and then ending the loop; S5. Perform ultrasonic rolling on the surface of the formed component to obtain a solid component.

2. The method for controlling the shape of ultrasonic rolling combined with laser selective melting according to claim 1, characterized in that: In step S1, a three-dimensional model is constructed for the component to be processed, the three-dimensional model is sliced ​​by slicing software, and the slice data and process parameters are input into a computer control center (8).

3. The method for controlling the shape of ultrasonic rolling combined with laser selective melting according to claim 1, characterized in that: In step S2, high-purity nitrogen is introduced into the forming cavity (15). After the oxygen content is reduced to a preset value, the printing program is started, the forming substrate (16) is lowered to a fixed height H, and the powder substrate (19) is raised to a height of 2H. The scraper (7) spreads the powder from the powder substrate (19) onto the forming substrate (16) and collects the excess powder into a recovery cylinder (11). After the powder is laid, the laser galvanometer (2) performs laser selective melting on the powder on the forming substrate (16) to obtain a solid layer. The cycle is repeated N times. After N solid layers are generated, the printing program is paused. The number of solid layers depends on the depth of the layer affected by the residual stress of ultrasonic rolling.

4. The method for controlling the shape of a composite ultrasonic rolling and laser selective melting according to claim 1, characterized in that: In step S3, the ultrasonic generator (13) is started to perform ultrasonic rolling on the surface of the solid layer to prepare the required component, and then reset after the processing is completed.

5. A device for implementing the method for controlling the shape of ultrasonic rolling combined with laser selective melting as claimed in any one of claims 1 to 4, characterized in that: The invention comprises an outer shell box (1), wherein the forming cavity (15) is opened inside the outer shell box (1), a laser galvanometer (2) is fixedly connected to the top wall of the forming cavity (15), an optical lens (3) is fixedly connected to the bottom surface of the laser galvanometer (2), an ultrasonic rolling assembly is arranged in the forming cavity (15), the optical lens (3) and the ultrasonic rolling assembly are located above the forming substrate (16), the scraper (7) is slidably connected in the forming cavity (15), the bottom end of the scraper (7) is in sliding contact with the bottom wall of the forming cavity (15), the scraper (7) is located above the forming substrate (16) and the powder substrate (19), and the forming substrate (16) and the powder substrate (19) are both slidably connected in the powder portion; The laser galvanometer (2), the ultrasonic rolling assembly and the computer control center (8) are electrically connected.

6. The device for controlling the shape of ultrasonic rolling combined with laser selective melting according to claim 5, characterized in that: The powder material section comprises a powder material cylinder (9), a forming cylinder (12), and a recovery cylinder (11) which are fixedly connected to the inside of the outer casing (1); the powder material cylinder (9), the forming cylinder (12), and the recovery cylinder (11) are arranged in sequence along the powder spreading direction; the forming base plate (16) is slidably connected to the inner side wall of the forming cylinder (12); the powder material base plate (19) is slidably connected to the inner side wall of the powder material cylinder (9); the bottom ends of the powder material base plate (19) and the forming base plate (16) are both fixedly connected to one end of a transmission rod (20); and the other end of the transmission rod (20) is transmission-connected to the lifting section.

7. The device for controlling the shape of ultrasonic rolling combined with laser selective melting according to claim 6, characterized in that: The lifting part comprises a second slider (21) fixedly connected to the bottom end of the transmission rod (20), the second slider (21) being transmission-connected to a second servo motor via a second lead screw, the second slider (21) being slidably connected to a guide rail (10), and the guide rail (10) being fixedly connected to the inner side wall of the outer shell box (1).

8. The device for controlling the shape of ultrasonic rolling combined with laser selective melting according to claim 6, characterized in that: One end of the scraper (7) is fixedly connected to a first slider (18), the first slider (18) is connected to the first servo motor and the first lead screw through a transmission, the first slider (18) is slidably connected to a slide rail (17), and the slide rail (17) is fixedly connected to the side wall of the forming cavity (15).

9. The device for controlling the shape of ultrasonic rolling combined with laser selective melting according to claim 5, characterized in that: The ultrasonic rolling assembly comprises an ultrasonic generator (13) and a mechanical arm (14) fixedly connected to the side wall of the forming cavity (15); the ultrasonic generator (13) is electrically connected to the computer control center (8); the end of the mechanical arm (14) is fixedly connected to a transducer (4); the transducer (4) is electrically connected to the computer control center (8); the bottom end of the transducer (4) is threadedly connected to a variable amplitude rod (5); the end of the variable amplitude rod (5) away from the transducer (4) is fixedly connected to a rolling head (6); the rolling head (6) and the forming substrate (16) are arranged correspondingly above and below.

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