Cutting and positioning method of brazing filler metal foil strip by adopting vacuum brazing process

Abstract

The invention provides a method for cutting and positioning a brazing filler metal foil strip by adopting a vacuum brazing process, which comprises the following steps of: 1, performing image recognition on a core body of a dot matrix sandwich structure to generate a two-dimensional image of the surface profile of the core body, including image acquisition, rapid image processing and profile recognition; 2, core contour parameters generated in the step 1 are guided into a control system, precise and lossless cutting is conducted on the brazing filler metal foil belt through the ultrafast laser machining technology, and the situation that the microstructure of the brazing filler metal belt is affected by excessive heat input is avoided; step 3, paving a plurality of layers of amorphous brazing filler metal strips prepared in the step 2 according to process requirements to form a complex variable-thickness brazing filler metal foil strip; the complex variable-thickness brazing filler metal foil belt is connected with the dot matrix sandwich structure panel through the micro-resistance spot welding technology, and precise positioning of the brazing filler metal foil belt is achieved. By precisely cutting and positioning the brazing filler metal foil strip, the weight increment of the brazing filler metal is reduced while the welding quality is guaranteed, and the lightweight requirement is met.

Description

Technical Field

[0001] The invention relates to the technical field of solder foil processing, in particular to a cutting and positioning method for a solder foil using a vacuum brazing process. Background Art

[0002] The lattice sandwich structure is a network-like geometric structure composed of a series of individual elements connected by joints. It is named because its microstructure is orderly and regular, and its form is similar to the microscopic crystal lattice configuration. Its components mainly bear axial loads, and the structural load-bearing efficiency can be improved by distributing materials to local discrete elements. Currently, common lattice sandwich structures include two-dimensional periodic lattice structures represented by honeycombs and corrugations and three-dimensional periodic lattice structures represented by pyramids and tetrahedrons. Due to the high specific strength and specific stiffness of the lattice sandwich structure, it is possible to achieve multifunctional properties such as energy absorption, heat insulation, and sound insulation by changing the sandwich filling material. This structure is widely used in aerospace, automobile, shipbuilding and other fields.

[0003] The lattice sandwich structure is usually composed of a lattice core and its upper and lower panels. Depending on the application scenario and conditions, the core structure usually includes a corrugated structure, a honeycomb structure, a pyramid structure, etc., and the panel / core materials include aluminum alloy, titanium alloy, high-temperature alloy, etc. Common connection methods between the core and the panel include vacuum brazing, adhesive bonding, resistance spot welding, etc. In the vacuum brazing process, the lattice sandwich structure often adopts the method of fully covering the upper and lower panels with amorphous foil solder strips, and the entire solder strip is embedded between the core and the panel. For a lattice sandwich structure with a thickness of more than 1mm, the solder strip weight gain is less than 2%; however, with the continuous improvement of lightweight requirements, the panel of the lattice sandwich structure will be thinned to 0.1-0.5mm, and the solder strip weight gain will reach 20%. The entire solder strip will not be conducive to the extreme lightweight requirements of the lattice sandwich structure. In addition, in the vacuum brazing process, only the brazing filler metal in the lattice core wall area plays a metallurgical bonding role. The remaining brazing filler metal strips not only have no beneficial effect on the formation of the welded joint, but also cause obvious melting effect, reducing the joint strength and panel mechanical properties, thereby affecting the various properties of the lattice sandwich structure. Summary of the invention

[0004] In view of the above problems, the present invention provides a method for cutting and positioning a solder foil strip using a vacuum brazing process.

[0005] To solve the above problems, the technical solution adopted by the present invention is:

[0006] A method for cutting and positioning a brazing foil strip using a vacuum brazing process comprises the following steps:

[0007] Step 1: Perform image recognition on the core of the lattice sandwich structure to generate a two-dimensional image of the core surface contour, including image acquisition, image fast processing, and contour recognition;

[0008] Step 2: Import the core contour parameters generated in step 1 into the control system, and use ultrafast laser processing technology to achieve accurate and non-destructive cutting of the solder foil to avoid excessive heat input affecting the microstructure of the solder foil;

[0009] Step 3: Lay out multiple layers of the amorphous solder foil prepared in step 2 according to process requirements to form a complex variable thickness solder foil; connect the complex variable thickness solder foil with the lattice sandwich structure panel using a micro-resistance spot welding process to achieve precise positioning of the solder foil;

[0010] Step 4: Use vacuum brazing to braze the core and the panel with the positioned brazing filler metal to prepare a lattice sandwich structure with light weight, small melting effect and good mechanical properties.

[0011] Preferably, the lattice sandwich structure is composed of a metal panel and a lattice core structure, and is formed by a vacuum brazing process. The vacuum brazing process uses amorphous foil as the brazing material. The metal panel and the lattice core material are titanium alloy or high-temperature alloy. The wall thickness of the lattice core is 0.02mm~0.5mm, and the thickness of the metal panel is 0.8mm~2.0mm. The lattice core is a three-dimensional periodic structure, which is any one of the four types of corrugated structure, honeycomb structure, pyramid structure, and complex core structure (honeycomb filled with corrugations, honeycomb filled with pyramids, etc.), and the lattice core is a curved structure.

[0012] Preferably, it includes image acquisition, rapid image processing, and contour recognition;

[0013] The image recognition technology is a non-contact real-time measurement method, which avoids the problem of low measurement accuracy caused by deformation of the lattice core during contact measurement, and is used to quickly detect the lattice core and generate a surface profile image;

[0014] The image recognition technology is suitable for measuring a surface with discontinuous features, and the proportion of the cross section of the dot matrix core wall to its total surface area is 5-70%.

[0015] Preferably, an industrial camera or a common camera can be used;

[0016] The camera detection accuracy is required to be less than 0.01mm (or 12 million pixels);

[0017] Can use natural light or bottom fill light;

[0018] No need for pre-treatment such as surface coating on the lattice core;

[0019] No need to combine gauge blocks, height meters and other devices, just need to obtain the top view of the lattice core;

[0020] The grayscale processing method is used to convert the color image of the top view of the dot matrix core into a black and white image, which reduces the subsequent processing time and storage space;

[0021] There is no need to identify individual cell nodes of the dot matrix core based on the corner detection algorithm. It is only necessary to sharpen the entire image and perform black and white recognition.

[0022] The width of the solder strip needs to cover the entire lattice core wall. After cutting, the width of the solder strip should be 2 to 5 times the lattice wall thickness. The influence of the core burr can be ignored, so there is no need to remove the burrs of the measurement data.

[0023] Convert color images to black and white;

[0024] Set the R, G, and B components of each pixel of the dot matrix core image to be equal, that is, R=G=B=V, where V is the grayscale value;

[0025] The gray value may be the maximum value among the three components of R, G, and B, or the average value of the three components of R, G, and B, or the weighted average value of the three components of R, G, and B;

[0026] Recognize the gray value of the black and white image after grayscale processing;

[0027] Extract the pixel points within the V value range of 1 to 100, and judge whether the width of the area where the gray value meets the requirements is less than 2 to 5 times the wall thickness of the dot matrix;

[0028] If it is less than 2 to 5 times the wall thickness of the lattice, the area is flattened to remove sporadic noise points;

[0029] If it is greater than 2 to 5 times the wall thickness of the dot matrix, the V value is further reduced and the process is repeated until the contour recognition is completed.

[0030] Preferably, the core body profile parameters are imported into the control system, and ultrafast laser processing technology is used to achieve accurate and non-destructive cutting of the solder foil strip to avoid excessive heat input affecting the microstructure of the solder strip;

[0031] The ultrafast laser processing technology uses a picosecond or femtosecond laser light source.

[0032] Preferably, the solder sheet is first fixed on the sample table by a clamping device;

[0033] Then set the laser parameters of the picosecond laser: the central wavelength of the picosecond laser is 1064nm, the repetition frequency is 250KHz, the single pulse energy is 200uJ@250kHz, the pulse width is 15ps, the laser output spot diameter is 1.2mm, the divergence angle is 2mrad, and the laser spot diameter after focusing by the galvanometer field lens is 0.05mm;

[0034] Then input the contour image parameter motion trajectory of laser cutting into the processing software, set the processing trajectory parameters, where the laser trajectory movement speed is 1000mm / s and the number of processing times is 10 times;

[0035] The processing software in the industrial computer is then used to control the picosecond laser to start emitting laser according to the laser parameters, and to control the two-dimensional galvanometer and the XY moving platform so that the laser moves along a predetermined trajectory to complete precise cutting operations on the solder foil.

[0036] Preferably, the solder sheet is first fixed on the sample table by a clamping device;

[0037] Then set the laser parameters of the femtosecond laser: the central wavelength of the femtosecond laser is 1064nm, the repetition frequency is 200KHz, the single pulse energy is 100uJ@200kHz, the pulse width is 200fs, and the laser spot diameter is 0.05mm after focusing by the galvanometer field lens;

[0038] Then input the contour image parameter motion trajectory of laser cutting into the processing software, set the processing trajectory parameters, where the laser trajectory movement speed is 1000mm / s and the number of processing times is 15 times;

[0039] The processing software in the industrial computer is then used to control the picosecond laser to start emitting laser according to the laser parameters, and to control the two-dimensional galvanometer and the XY moving platform so that the laser moves along a predetermined trajectory to complete precise cutting operations on the solder foil.

[0040] Preferably, the solder foil strip is composed of multiple layers of amorphous solder foil strips, and has the characteristics of complex geometric shape and variable thickness;

[0041] The solder foil has a similar shape to the lattice core, and the solder foil seam width should be 2 to 5 times the wall thickness of the lattice core;

[0042] The solder foil with constant thickness is suitable for welding flat and large curvature cores, while the solder foil with variable thickness is suitable for welding small curvature and complex curved cores, so that the solder between the panel and the lattice core can fill the soldering gap well, without poor soldering angle formation due to insufficient solder, and without corrosion of the base material or even adhesion of the fixture due to excessive solder.

[0043] Welding high-temperature alloy panels and cores, using nickel-based amorphous foil;

[0044] Welding titanium alloy faceplate and core, using titanium-based amorphous foil;

[0045] The thickness of amorphous foil is 0.05-0.10 mm.

[0046] Preferably, the prepared amorphous solder foil is laid out into multiple layers according to the process requirements, and connected by a micro-resistance spot welding process to form a complex variable thickness solder foil;

[0047] The complex variable thickness solder foil is connected to the lattice sandwich structure panel using micro-resistance spot welding technology to achieve precise positioning of the solder foil and avoid movement and dislocation of the solder foil in subsequent processes.

[0048] Preferably, medium frequency or high frequency inverter current and inert gas extremely fast cooling are used; the key process parameters are welding current, welding time, electrode pressure, and electrode head size;

[0049] The welding current is 100-1500A; preferably 300-1000A, more preferably 500-800A;

[0050] The welding time is 2 to 20 ms; preferably 3 to 10 ms, more preferably 5 to 8 ms;

[0051] The electrode pressure is 10 to 200 N, preferably 40 to 100 N, more preferably 60 to 80 N;

[0052] The electrode size is 1 to 10 mm, preferably 2 to 8 mm, and more preferably 3 to 5 mm.

[0053] The beneficial effects of the present invention are:

[0054] 1. It can effectively prepare complex variable thickness solder foil strips, so that the solder between the panel and the lattice core can better fill the soldering gap, avoid poor soldering angle formation due to insufficient solder, and prevent problems such as base material dissolution and adhesion of fixtures caused by excessive solder, and achieve high-quality connection of metal lattice sandwich structures.

[0055] 2. For the thinned lattice sandwich structure panel, the problem of excessive weight gain of the entire solder strip, which is not conducive to the extreme lightweight demand, is avoided. By accurately cutting and positioning the solder foil strip, the weight gain of the solder is reduced while ensuring the welding quality, thus meeting the lightweight requirements.

[0056] 3. Image recognition technology is a non-contact real-time measurement method, which avoids the problem of low measurement accuracy caused by deformation of the lattice core during contact measurement. It can quickly detect the lattice core and generate surface contour images, providing accurate parameters for subsequent precise cutting.

[0057] 4. Ultrafast laser cutting technology enables precise and non-destructive cutting of solder foil, avoiding excessive heat input affecting the microstructure of the solder foil and ensuring solder performance. The micro-resistance spot welding process connects the complex variable thickness solder foil with the lattice sandwich structure panel, achieving precise positioning of the solder foil and avoiding movement and dislocation in subsequent processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a flow chart of the present invention.

[0059] Figure 2 It is the outline diagram of the core of the present invention.

[0060] Figure 3 This is the laser processing path diagram of the present invention.

[0061] Figure 4 This is a table of process parameters for solder strip micro-resistance spot welding of the present invention.

[0062] Figure 5 It is a time-temperature curve diagram of the vacuum brazing process of the present invention. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0064] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0065] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] Reference Figure 1-5 A cutting and positioning method for brazing foil strips using a vacuum brazing process is designed to solve the technical problems of poor local brazing quality and increased brazing weight that reduce the lightweight level of sandwich structures during vacuum brazing of metal sandwich structures. The method achieves the preparation of a lattice sandwich structure with light weight, small ablation effect and good mechanical properties through image recognition, ultrafast laser cutting, multi-layer amorphous brazing strip laying, micro-resistance spot welding, vacuum brazing and other steps.

[0067] Image Recognition

[0068] Image acquisition: Industrial cameras or ordinary cameras can be used for image acquisition. The camera detection accuracy is required to be less than 0.01mm (or 12 million pixels), and natural light or bottom fill light can be used. There is no need to pre-treat the dot matrix core by coating the surface, or to combine gauge blocks, height meters and other devices. It only needs to obtain a top view of the dot matrix core.

[0069] Fast image processing: The grayscale processing method is used to convert the color image of the top view of the dot matrix core into a black and white image, reducing the subsequent processing time and storage space. There is no need to identify the individual cell nodes of the dot matrix core based on the corner detection algorithm. It is only necessary to sharpen the overall image for black and white recognition.

[0070] Contour recognition: grayscale value recognition is performed on the grayscale processed black and white image. First, the pixel points in the V value range of 1 to 100 are extracted to determine whether the width of the area where the grayscale value meets the requirements is less than 2 to 5 times the thickness of the dot matrix wall. If it is less than, the area is flattened to remove sporadic noise points; if it is greater, the V value is further reduced and the process is repeated until the contour recognition is completed.

[0071] Ultrafast laser cutting

[0072] Technical principle: Ultrafast laser processing technology uses picosecond or femtosecond laser light sources. Due to its extremely short pulse, the energy is injected in a very short time, the heat cannot diffuse, and chemical reactions such as thermal oxidation of the material will not occur, thus ensuring the material performance and processing quality, and having a "cold processing" effect.

[0073] Picosecond laser cutting process:

[0074] The solder sheet is fixed on the sample stage by a clamping device to ensure the stability of the solder sheet during the cutting process.

[0075] The laser parameters of the picosecond laser were set as follows: the central wavelength was 1064 nm, the repetition frequency was 250 KHz, the single pulse energy was 200 uJ @ 250 kHz, the pulse width was 15 ps, the laser output spot diameter was 1.2 mm, the divergence angle was 2 mrad, and the laser spot diameter was 0.05 mm after focusing by the galvanometer field lens.

[0076] The contour image parameter motion trajectory of laser cutting is input into the processing software, and the processing trajectory parameters are set, where the laser trajectory movement speed is 1000mm / s and the number of processing times is 10 times.

[0077] The processing software in the industrial computer controls the start of the picosecond laser to emit laser according to the laser parameters, and controls the two-dimensional galvanometer and the XY moving platform to make the laser move along the predetermined trajectory to complete precise cutting operations on the solder foil.

[0078] Femtosecond laser cutting process:

[0079] Similarly, the solder sheet is fixed on the sample stage by a clamping device.

[0080] The laser parameters of the femtosecond laser were set as follows: the central wavelength was 1064 nm, the repetition frequency was 200 KHz, the single pulse energy was 100 uJ @ 200 kHz, the pulse width was 200 fs, and the laser spot diameter was 0.05 mm after focusing by the galvanometer field lens.

[0081] The contour image parameter motion trajectory of laser cutting is input into the processing software, and the processing trajectory parameters are set, where the laser trajectory movement speed is 1000mm / s and the number of processing times is 15 times.

[0082] The processing software in the industrial computer controls the start of the picosecond laser to emit laser according to the laser parameters, and controls the two-dimensional galvanometer and the XY moving platform to make the laser move along the predetermined trajectory to complete precise cutting operations on the solder foil.

[0083] Multilayer amorphous solder tape laying and micro-resistance spot welding process

[0084] Laying down of multi-layer amorphous solder foil: The solder foil is composed of multi-layer amorphous solder foil, which has the characteristics of complex geometric shape and variable thickness. The multi-layer amorphous solder foil is laid according to the process requirements to form a complex variable thickness solder foil. The solder foil has a similar shape to the lattice core, and the solder foil seam width should be 2 to 5 times the wall thickness of the lattice core. The uniform thickness solder foil is suitable for welding flat and large curvature cores, and the variable thickness solder foil is suitable for welding small curvature and complex curved cores, so that the solder between the panel and the lattice core can fill the solder gap well, and the solder angle will not be poorly formed due to insufficient solder, nor will the parent material be dissolved or even the fixture be adhered due to excessive solder.

[0085] Micro resistance spot welding process:

[0086] Adopt medium frequency or high frequency inverter current and inert gas rapid cooling. This can improve welding efficiency and quality, and prevent the welding joint from being oxidized at high temperature.

[0087] The key process parameters are welding current, welding time, electrode pressure, and electrode head size. The welding current is 100-1500A, preferably 300-1000A, and more preferably 500-800A; the welding time is 2-20ms, preferably 3-10ms, and more preferably 5-8ms; the electrode pressure is 10-200N, preferably 40-100N, and more preferably 60-80N; the electrode size is 1-10mm, preferably 2-8mm, and more preferably 3-5mm. By reasonably controlling these parameters, high-quality welded joints can be achieved to ensure that the connection between the solder foil and the lattice sandwich structure panel is firm and reliable.

[0088] Connect the complex variable thickness solder foil with the lattice sandwich structure panel to achieve precise positioning of the solder foil and avoid movement and dislocation of the solder foil in subsequent processes.

[0089] Vacuum brazing

[0090] The core and the panel are connected by vacuum brazing with the positioned brazing filler metal, so as to obtain a lattice sandwich structure with light weight, small melting effect and good mechanical properties.

[0091] Advantages of ultrafast laser cutting technology

[0092] High precision: The laser spot diameter is small, which can achieve high-precision cutting and meet the cutting requirements of solder foils with complex shapes and sizes.

[0093] Non-destructive cutting: The "cold working" effect avoids the influence of excessive heat input on the microstructure of the solder strip, ensuring the performance and quality of the solder.

[0094] High flexibility: According to the different shapes and sizes of the lattice sandwich structure core, the laser cutting parameters and trajectories can be flexibly adjusted to achieve personalized cutting solutions.

[0095] High efficiency: Laser cutting has a high speed, which can improve production efficiency and reduce production costs.

[0096] Advantages of Micro Resistance Spot Welding Process

[0097] Precise positioning: Achieve precise positioning of the solder foil to avoid movement and dislocation in subsequent processes.

[0098] Firm and reliable connection: The formed metallurgical joint has high strength and reliability, which can meet the use requirements of the lattice sandwich structure in various harsh environments.

[0099] Strong adaptability: It is suitable for welding workpieces of different materials and thicknesses, and has strong adaptability and versatility.

[0100] Efficient production: simple operation, high production efficiency, and able to meet the needs of large-scale production.

[0101] In summary, this method provides an effective solution for high-quality connection of lattice sandwich structures through the synergistic effect of image recognition, ultrafast laser cutting, multi-layer amorphous solder tape laying and micro-resistance spot welding process, vacuum brazing and other steps.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for cutting and positioning a brazing foil strip using a vacuum brazing process, characterized in that: The following steps are involved: Step 1: Perform image recognition on the core of the lattice sandwich structure to generate a two-dimensional image of the core surface contour, including image acquisition, image fast processing, and contour recognition; Step 2: Import the core contour parameters generated in step 1 into the control system, and use ultrafast laser processing technology to achieve accurate and non-destructive cutting of the solder foil to avoid excessive heat input affecting the microstructure of the solder foil; Step 3: Lay out multiple layers of the amorphous solder foil prepared in step 2 according to process requirements to form a complex variable thickness solder foil; connect the complex variable thickness solder foil with the lattice sandwich structure panel using a micro-resistance spot welding process to achieve precise positioning of the solder foil; Step 4: Use vacuum brazing to braze the core and the panel with the positioned brazing filler metal to prepare a lattice sandwich structure with light weight, small melting effect and good mechanical properties.

2. The lattice sandwich structure according to claim 1, characterized in that: The lattice sandwich structure consists of a metal panel and a lattice core structure, and is formed by a vacuum brazing process. The vacuum brazing process uses an amorphous foil as a brazing material. The metal panel and the lattice core material are titanium alloy or high-temperature alloy. The wall thickness of the lattice core is 0.02mm to 0.5mm, the thickness of the metal panel is 0.8mm to 2.0mm, and the lattice core is a three-dimensional periodic structure.

3. The image processing method according to claim 1, characterized in that: Includes image acquisition, fast image processing, and contour recognition; The image recognition technology is a non-contact real-time measurement method, which avoids the problem of low measurement accuracy caused by deformation of the lattice core during contact measurement, and is used to quickly detect the lattice core and generate a surface profile image; The image recognition technology is suitable for measuring a surface with discontinuous features, and the proportion of the cross-section of the wall of the dot matrix core body to its total surface area is 5-70%.

4. The image processing method according to claim 3, characterized in that: Industrial cameras and ordinary cameras can be used; The camera detection accuracy is required to be less than 0.01mm; Can use natural light or bottom fill light; No need for pre-treatment such as surface coating on the lattice core; No need to combine gauge blocks, height meters and other devices, just need to obtain the top view of the lattice core; The grayscale processing method is used to convert the color image of the top view of the dot matrix core into a black and white image, which reduces the subsequent processing time and storage space; There is no need to identify individual cell nodes of the dot matrix core based on the corner detection algorithm. It is only necessary to sharpen the entire image and perform black and white recognition. The width of the solder strip needs to cover the entire lattice core wall. After cutting, the width of the solder strip should be 2 to 5 times the lattice wall thickness. The influence of the core burr can be ignored, so there is no need to remove the burrs of the measurement data. Convert color images to black and white; Set the R, G, and B components of each pixel of the dot matrix core image to be equal, that is, R=G=B=V, where V is the grayscale value; The gray value may be the maximum value among the three components of R, G, and B, or the average value of the three components of R, G, and B, or the weighted average value of the three components of R, G, and B; Recognize the gray value of the black and white image after grayscale processing; Extract the pixel points within the V value range of 1 to 100, and judge whether the width of the area where the gray value meets the requirements is less than 2 to 5 times the wall thickness of the dot matrix; If it is less than 2 to 5 times the wall thickness of the lattice, the area is flattened to remove sporadic noise points; If it is greater than 2 to 5 times the wall thickness of the dot matrix, the V value is further reduced and the process is repeated until the contour recognition is completed.

5. The cutting method according to claim 1, characterized in that: The core profile parameters are imported into the control system, and ultrafast laser processing technology is used to achieve accurate and non-destructive cutting of the brazing foil strip, avoiding excessive heat input affecting the microstructure of the brazing strip; The ultrafast laser processing technology uses a picosecond or femtosecond laser light source.

6. The cutting method according to claim 5, characterized in that: First, fix the solder sheet on the sample table through a clamping device; Then set the laser parameters of the picosecond laser: the central wavelength of the picosecond laser is 1064nm, the repetition frequency is 250KHz, the single pulse energy is 200uJ@250kHz, the pulse width is 15ps, the laser output spot diameter is 1.2mm, the divergence angle is 2mrad, and the laser spot diameter after focusing by the galvanometer field lens is 0.05mm; Then input the contour image parameter motion trajectory of laser cutting into the processing software, set the processing trajectory parameters, where the laser trajectory movement speed is 1000mm / s and the number of processing times is 10 times; The processing software in the industrial computer is then used to control the picosecond laser to start emitting laser according to the laser parameters, and to control the two-dimensional galvanometer and the XY moving platform so that the laser moves along a predetermined trajectory to complete precise cutting operations on the solder foil.

7. The cutting method according to claim 6, characterized in that: First, fix the solder sheet on the sample table through a clamping device; Then set the laser parameters of the femtosecond laser: the central wavelength of the femtosecond laser is 1064nm, the repetition frequency is 200KHz, the single pulse energy is 100uJ@200kHz, the pulse width is 200fs, and the laser spot diameter is 0.05mm after focusing by the galvanometer field lens; Then input the contour image parameter motion trajectory of laser cutting into the processing software, set the processing trajectory parameters, where the laser trajectory movement speed is 1000mm / s and the number of processing times is 15 times; The processing software in the industrial computer is then used to control the picosecond laser to start emitting laser according to the laser parameters, and to control the two-dimensional galvanometer and the XY moving platform so that the laser moves along a predetermined trajectory to complete precise cutting operations on the solder foil.

8. The solder foil strip according to claim 1, characterized in that: The solder foil strip is composed of multiple layers of amorphous solder foil strips, and has the characteristics of complex geometric shapes and variable thickness; The solder foil has a similar shape to the lattice core, and the solder foil seam width should be 2 to 5 times the wall thickness of the lattice core; The solder foil with constant thickness is suitable for welding flat and large curvature cores, while the solder foil with variable thickness is suitable for welding small curvature and complex curved cores, so that the solder between the panel and the lattice core can fill the soldering gap well, without poor soldering angle formation due to insufficient solder, and without corrosion of the base material or even adhesion of the fixture due to excessive solder. Welding high-temperature alloy panels and cores, using nickel-based amorphous foil; Welding titanium alloy faceplate and core, using titanium-based amorphous foil; The thickness of amorphous foil is 0.05-0.10 mm.

9. The solder foil positioning method according to claim 8, characterized in that: The prepared amorphous solder foil strips are laid out in multiple layers according to the process requirements and connected by micro-resistance spot welding process to form complex variable thickness solder foil strips; The complex variable thickness solder foil is connected to the lattice sandwich structure panel using micro-resistance spot welding technology to achieve precise positioning of the solder foil and avoid movement and dislocation of the solder foil in subsequent processes.

10. The spot welding process according to claim 1, characterized in that: Adopt medium frequency or high frequency inverter current and extremely fast cooling of inert gas; The welding current is 100-1500A; The welding time is 2 to 20 ms; The electrode pressure is 10-200N; The electrode size is 1-10 mm.

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