Preparation process of porous needle plate with fine spacing, ordered and dense arrangement and porous needle plate mold

Abstract

The invention discloses a preparation process of a fine-spacing ordered dense-arrangement porous needle plate. The preparation process comprises the following steps: designing a three-dimensional model of a needle plate mold, reserving hole site marking points, setting laser processing parameters according to the characteristics of selected materials and the precision of the required mold, filling selected metal powder, and manufacturing a needle plate mold blank through a 3D metal printing technology; according to the performance requirements of the selected materials, the needle plate mold blank is subjected to heat treatment; and a machine vision system is used for recognizing reserved hole site mark points and correcting positioning deviation, different laser machining parameters are selected according to the surface quality grade of the mold, fine machining of the inner surface of a micropore is achieved through the laser technology, and the high-quality needle plate mold is obtained. The invention further discloses a porous needle plate mold. By adopting the device and the method, the problems of difficulty in positioning, low machining efficiency, non-uniform hole distribution, overlarge hole pitch, rough hole wall and the like during micropore machining are solved, and efficient preparation of the high-precision needle plate mold with numerous micropores, small hole pitch and ordered arrangement of the micropores is successfully realized.

Description

Technical Field

[0001] The present invention relates to the field of precision mold manufacturing, and particularly to a preparation process for a micro-spacing orderly densely arranged porous needle plate and a porous needle plate mold. Background Art

[0002] Traditional methods for manufacturing needle plate molds often rely on complex machining processes. For needle plate molds with a large number of tiny holes, mechanical drilling using micro-drills is usually employed. This method has many problems. It is difficult to achieve small holes with a diameter less than 0.2 mm by mechanical drilling, with large hole diameter errors, low machining accuracy, and long machining times. Moreover, only one hole can be machined at a time and it needs to be carried out sequentially. At the same time, it is necessary to clean up debris and solve the problem of heat generation during machining. In addition, current commonly used laser drilling and electrical discharge machining technologies also have certain limitations. For example, in the "Array-Type Intelligent Laser Drilling Mechanism" mentioned in Chinese invention patent CN201810012135.8, although a certain number of single-row holes can be machined in one go, due to the size of the laser drilling generating device, it is impossible to achieve a millimeter-level small hole spacing. And in the "Electrical Discharge Drilling Device and Electrical Discharge Drilling Method" mentioned in Chinese invention patent CN202410696601.4, although the drilling efficiency is improved, due to the limitation of the size of the motor chuck, only a certain number of tool electrodes can be installed, resulting in a limited number of holes drilled each time and unable to achieve unified machining of complex densely arranged small holes. At the same time, laser drilling is limited by the thickness of the processed material, and electrical discharge machining not only has a slow speed but is also limited by the type of processed material. Currently, there is no technology that combines 3D metal printing technology and femtosecond laser processing technology to prepare molds with numerous micro-holes.

[0003] In summary, traditional micro-hole manufacturing methods and existing patents cannot meet the requirements of an increasingly smaller micro-hole spacing of the needle plate and the high-efficiency and low-cost of the industry. Therefore, there is an urgent need for a new preparation process to effectively solve problems such as difficult positioning, low efficiency, uneven hole distribution, too large hole spacing, and rough hole walls in micro-hole machining, and to promote the further development of micro-hole manufacturing technology. Summary of the Invention

[0004] The technical problem to be solved by the embodiments of the present invention is to provide a preparation process for a micro-spacing orderly densely arranged porous needle plate and a porous needle plate mold, which can accurately position and machine micro-holes.

[0005] To solve the above technical problem, the embodiments of the present invention provide a preparation process for a micro-spacing orderly densely arranged porous needle plate, which is characterized by including the following steps: S1: Design the three-dimensional model of the mold, reserve hole position marking points, set laser processing parameters according to the characteristics of the selected material and the accuracy requirements of the required mold, fill the selected metal powder, and manufacture the blank of the needle plate mold through 3D metal printing technology; S2: Heat-treat the blank of the needle plate die according to the performance requirements of the selected material. S3: Identify the reserved hole position marking points through machine vision and correct the positioning deviation. Select different laser processing parameters according to the surface quality grade of the die, and finely process the inner surface of the micro-needle holes in the blank of the needle plate die.

[0006] Further, the reserved hole position marking points are pits with a diameter of 0.10 - 0.20 mm, a thickness of 0.06 - 0.10 mm, and a depth of 0.3 - 0.8 mm.

[0007] Further, the laser processing parameters include the molten pool area and the energy density. The molten pool area is used to optimize the scanning strategy, and the calculation method of the molten pool area is:

[0008] where A is the molten pool area, P is the laser power, v is the scanning speed, and d is the spot diameter, and the value is less than or equal to half of the processing hole diameter. The energy density is used to ensure that the metal powder is fully melted and defect-free, and the calculation method of the energy density is:

[0009] where E_effective is the energy density, σ is the absorption rate of the material to the laser, h is the layer thickness, and s is the line spacing.

[0010] Further, the metal powder material is one or more of stainless steel, titanium alloy, aluminum alloy, or copper alloy.

[0011] Further, the heat treatment includes solution treatment and aging treatment, and includes the steps of: Heat the blank of the needle plate die to 1000 °C, keep it warm for 2 hours and then quickly cool it to improve the uniformity and hardness of the material. Then heat the blank of the needle plate die to 500 °C and keep it warm for 6 hours to further improve the strength and hardness of the material.

[0012] Further, the method of machine vision recognition includes: Real-time monitor the array of reserved hole position marking points through a machine vision system optimized by deep learning methods. Adopt a fine-tuning algorithm based on adaptive adjustment of monomer parameters for the correction process of positioning deviation to achieve high-precision dynamic compensation.

[0013] Further, the steps of correcting the positioning deviation include: S301: Scan the acquired image of the needle plate mold from the upper left corner to the lower right corner, perform global threshold segmentation, isolate non-connected regions, select the target and optimize the image in the target region, calculate the area of the region to be measured. If the area of the region to be detected is greater than a predetermined value, re-segment the image; otherwise, calculate the central coordinates of the reserved hole position markers in the region to be detected. S302: Perform an affine transformation on the central coordinate positions of the reserved hole position markers to obtain the positioning of several actual detection regions. S303: Extract the images of the reserved hole position markers and remove the background to reduce the number of subsequent calculations. S304: Transmit the positioning information of the reserved hole position markers into the computer to provide accurate positioning information for subsequent laser processing.

[0014] Further, the deep learning method includes one of the YOLOv5 model and the SSD model.

[0015] Further, the surface quality grade of the mold includes Grade A surface: Ra ≤ 0.1, Grade B surface: 0.1 < Ra ≤ 1, Grade C surface: 1 < Ra ≤ 10. Among them, is the arithmetic mean roughness, and the calculation method is:

[0016] Among them, k is the material coefficient, with a value range of 0 - 1, f is the pulse frequency, v is the feed rate, α is the starting radius angle, β is the ending radius angle, P is the laser power, d is the single-layer feed amount, and Δz is the defocus amount.

[0017] Correspondingly, the embodiment of the present invention also provides a porous needle plate mold obtained according to the above method, including a bottom plate (1), positioning holes (2), connection holes (3), and micro-needle holes (4). The positioning holes (2) are distributed on the central axis of the bottom plate (1) and close to the edge position. The connection holes (3) are distributed on the diagonal of the bottom plate (1) and close to the edge position. The micro-needle holes (4) are arranged in an orderly manner in the central area of the bottom plate (1). Among them, the cross-section of the micro-needle hole (4) is circular, with a diameter of 0.15 mm, 30 rows, 61 columns, a total of 1830 holes, and the adjacent row spacing and column spacing are both 0.325 mm.

[0018] Implementing the embodiment of the present invention has the following beneficial effects: 1. In the process of the present invention, a rough blank of a needle plate mold with a complex shape is rapidly manufactured by 3D metal printing technology. By using the unique "additive manufacturing" method of 3D metal printing technology to replace the traditional "subtractive manufacturing" method, it is possible to achieve the integrated forming of complex porous structures without machining each hole one by one. Thus, hundreds of holes in different rows and columns can be generated synchronously in a single manufacturing process, greatly improving the efficiency and design freedom. According to actual needs, the spacing, diameter, and quantity of the micro needle holes on the needle plate mold can be flexibly designed. In addition, solution treatment and aging treatment are carried out on the manufactured needle plate mold to improve the strength and hardness of the mold. Moreover, the hole walls of the mold are finely processed by femtosecond laser processing technology, which not only improves the smoothness of the hole walls but also enhances their anti-wear and anti-corrosion capabilities, greatly extending the service life of the mold. The combination of the two solves the problems of low micro-hole processing efficiency, uneven hole distribution, too large hole spacing, and rough hole walls, and successfully realizes the efficient preparation of a high-precision needle plate mold with numerous micro-holes, small hole spacing, and orderly arrangement of micro-holes, providing a more advanced and reliable mold manufacturing solution for the diamond cold press equipment field and promoting the development of the industry towards higher precision and higher efficiency.

[0019] 2. In the process of the present invention, by combining 3D metal printing technology and laser processing and introducing machine vision and deep learning technologies, the problem of difficult positioning in micro-hole processing is solved. Specifically, by increasing the number of detection heads and using depthwise separable convolution, the marking features of tiny reserved hole sites can be quickly identified; at the same time, DSCBS units and coordinate attention modules are inserted to further optimize the effect of lightweight and high-precision detection. In addition, by using the principle of position point mapping, the coordinate positions of the collected images are converted into the positioning information required for laser processing, thus realizing the seamless connection between 3D metal printing technology and laser processing. The entire process can be completed on one device, significantly improving the preparation efficiency of the needle plate mold and ensuring the accuracy and stability of micro-hole processing.

[0020] 3. Before implementing laser processing, by establishing a database of mold surface quality grades and laser processing parameters in a computer, the present invention can select appropriate laser processing parameters according to the mold surface quality grades. By precisely controlling the process parameters, the consistency between the mold surface roughness and the calculated value can be achieved, thus ensuring the surface smoothness. At the same time, this method maximally protects the surface quality of the mold and significantly improves the hardness, wear resistance, and corrosion resistance of the mold surface, ultimately extending the service life of the mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic flow chart of the preparation process of the present invention; Figure 2 is a schematic flow chart of the machine vision system identifying the marking points of reserved hole positions and correcting the positioning deviation; Figure 3 It is a three-dimensional structure schematic diagram of the porous needle plate mold of the present invention; Figure 4 It is a schematic diagram of the dimension marking of the porous needle plate mold of the present invention Figure 5 It shows Figure 4 A partial enlarged schematic diagram of part A in Specific embodiments

[0022] In the description of this embodiment, it should be understood that the terms "diameter", "depth", "thickness", "upper", "vertical", "horizontal", "center", "diagonal", "inner", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, 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, so it cannot be understood as a limitation to the present invention.

[0023] The following combines the attached Figures 1 to 5 The preferred embodiments of the present invention are described. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0024] In a specific embodiment of this embodiment, as Figure 1 shown, a preparation process of a micro-spacing ordered densely packed porous needle plate is implemented through the following steps.

[0025] S1: Design a three-dimensional model of the needle plate mold through CAD software, reserve hole position marking points, set laser processing parameters according to the characteristics of the selected material and the required accuracy of the mold, fill the selected metal powder, and manufacture the blank of the needle plate mold through 3D metal printing technology.

[0026] The reserved hole position marking points are pits with a diameter of 0.15 mm, a thickness of 0.08 mm, and a depth of 0.5 mm.

[0027] Specifically, first, draw a sketch of the basic contour of the needle plate mold in the selected 3D CAD software, and clearly mark the positions and quantities of the positioning holes 2, connection holes 3, and micro-needle holes 4 in the sketch. The positions and quantities of these holes are pre-designed according to the usage requirements of the mold. Then, use the stretching tool of the software to directly stretch the sketch with hole position marks into a 3D model to form the main structure of the needle plate mold. During the stretching process, set the stretching height according to the design requirements to ensure that the thickness of the mold meets the actual usage requirements. Subsequently, create a rectangular sketch on the reference plane 0.5 mm away from the surface inside the needle plate mold. The shape and size of this sketch are slightly larger than the area of the micro-needle hole 4, so as to cover the micro-needle hole 4 area. Use the stretching tool to stretch this sketch downward by 0.08 mm to convert it into a solid feature, thereby dividing the through-hole of the micro-needle hole into upper and lower parts. When detecting from top to bottom, each micro-needle hole shows a pit shape, which is the above-mentioned reserved hole position marking point. These marking points facilitate the precise identification of the machine vision system, and then correct the positioning error of the needle plate mold blank, ensuring that in the subsequent femtosecond laser processing process, the micro-needle hole 4 array can achieve high-precision alignment.

[0028] In the above, the metal powder material is one or more of stainless steel, titanium alloy, aluminum alloy, or copper alloy.

[0029] Preferably, the laser parameters include processing technology, laser type, molten pool area, and energy density; the laser processing technology is any one of selective laser melting or electron beam melting; the laser type is any one of green laser or red laser; The molten pool area is used to optimize the scanning strategy: (1); Among them, is the molten pool area, is the laser power, is the scanning speed, is the spot diameter, and its value is less than or equal to half of the processing hole diameter; The energy density is used to ensure that the metal powder is fully melted and defect-free: (2); Among them, is the energy density, is the absorption rate of the material to the laser (green laser: 0.4 - 0.6, infrared laser: 0.05 - 0.15), is the layer thickness, is the line spacing.

[0030] In some embodiments of the present invention, the scanning strategy is optimized through the correlation between the molten pool area and the laser processing parameters. Specifically, laser parameters with high power and low scanning speed can form a large molten pool, which helps to improve the fusion efficiency of the main structure; while laser parameters with low power and high scanning speed form a small molten pool, which is beneficial to ensuring the accuracy of the micro-holes. At the same time, the data of the molten pool area is related to the geometric features of the preliminary forming of the micro-holes, providing a basis for the femtosecond laser finishing. If the molten pool area fluctuates greatly, it may lead to stepped defects on the hole wall. In this case, the scanning times of the femtosecond laser need to be increased in the finishing stage. In addition, the pulse frequency and defocus amount of the femtosecond laser can be adjusted according to the historical data of the molten pool area to ensure that the surface quality level of the micro-needle hole 4 meets the predetermined requirements. Finally, the molten pool area and the corresponding laser processing parameters are stored in the database and classified according to the die quality level (such as A, B, C levels) to achieve intelligent parameter recommendation, thereby significantly reducing the trial-and-error cost and improving the preparation efficiency.

[0031] As one of the specific implementation manners of this embodiment, the selected metal powder material is copper alloy powder, and the selected laser processing technology is selective laser melting. Copper alloy has a high reflectivity and high thermal conductivity, and a relatively high laser power is required to ensure sufficient melting of the powder. Therefore, a 500W green laser is used, and the scanning speed is set to 1000mm / s for printing the main structure of the needle plate die, taking into account both melting and efficiency. When printing the area of the micro-needle hole 4, the power is reduced to 300W and the speed is increased to 1500mm / s to meet the high-precision requirements of the micro-holes. The powder spot diameter is set to 0.05mm to ensure concentrated energy and a reasonable molten pool size. The scanning line distance is set to 0.08mm to ensure close connection of the molten pools, and the layer thickness is set to 0.04mm, taking into account both precision and efficiency. By reasonably selecting and optimizing these laser parameters, a needle plate die blank can be manufactured in a 3D metal printing device, ensuring good printing quality and efficiency when printing the needle plate die with copper alloy powder.

[0032] Specifically, after 3D metal printing is completed, a high-precision confocal laser scanner integrated in the 3D printing device is used to perform non-contact detection on the wall of the micro-needle hole 4. By measuring the reflection signal at the edge of the hole opening, the hole opening diameter is calculated. The laser focus is vertically moved along the hole wall, and the focus displacement difference is recorded to determine the hole depth. If the detected hole diameter or depth exceeds the design tolerance, the system automatically marks the abnormal hole position. According to the detection results, parameters such as the power and scanning times of the subsequent femtosecond laser processing are adjusted to compensate for the errors in the hole diameter and depth. Through the above detection and compensation process, it is ensured that the hole diameter and depth of the micro-needle hole 4 meet the design requirements.

[0033] In S2, the heat treatment method is solution treatment and aging treatment.

[0034] Specifically, first heat the blank of the needle plate mold to 1000 °C, keep it warm for 2 hours and then quickly cool it to improve the material uniformity and hardness. Then heat the blank of the needle plate mold to 500 °C and keep it warm for 6 hours to further improve the material strength and hardness.

[0035] In S3, the machine vision system optimized by deep learning technology monitors the reserved hole position marking point array in real time.

[0036] For the correction process of the positioning deviation, a fine-tuning algorithm based on the adaptive adjustment of monomer parameters is adopted to achieve high-precision dynamic compensation.

[0037] Specifically, the deep learning technology can adopt the YOLOv5 (You Only Look at Once v5) model, SSD (Single Shot MultiBox Detector) model or other object detection models. Before being officially used for image detection, these models need to be pre-trained through a marked data set. Usually, different data sets with reserved marking points are used for the training data set, and the method of re-inspection marking training is adopted to further optimize the model performance.

[0038] Combined Figure 2 As shown, the steps for correcting the positioning deviation include: S301: Scan the collected needle plate mold image from the upper left corner to the lower right corner, perform global threshold segmentation, separate non-connected regions, select the target and optimize the image in the target region, calculate the area of the region to be measured. If the area of the region to be detected is greater than the predetermined value, re-segment the image, otherwise calculate the center coordinates of the reserved hole position marking points in the region to be detected.

[0039] S302: Perform an affine transformation on the center coordinate position of the reserved hole position marking points to obtain the positioning of several actual detection regions.

[0040] S303: Extract the image of the reserved hole position marking points and delete the background to reduce the number of subsequent calculations.

[0041] S304: Transmit the positioning information of the reserved hole position marking points into the computer to provide accurate positioning information for subsequent laser processing.

[0042] In S302, input the center coordinate data of the reserved hole position marking points calculated based on S301. According to the correspondence between the actual coordinates (theoretical design position) and the image detection coordinates (actual position) of the reserved hole position marking points, through Formula calculation.

[0043] Among them, Is the image detection coordinate, are the coordinates in the actual coordinate system, and the matrix parameters a, b, c, d, e, f are obtained by least squares fitting. The coordinates of all the marked points of the reserved hole positions in the image are mapped to the actual machining coordinate system through the transformation matrix to eliminate the positioning deviation caused by the shooting angle, lens distortion or blank position offset.

[0044] In S3, the machine vision adopts the improved YOLOv5s large model. First, the number of network detection heads is increased to extract higher-level semantic information related to the marked points of the reserved hole positions. Secondly, a group of depthwise separable convolutions are added to extract the features of the marked points of the reserved hole positions, and the DSCBS unit is inserted to reduce the number of calculations. Finally, by inserting a coordinate attention module at the early end of the backbone network, the direction of feature extraction can be more efficiently guided at the initial stage of feature extraction.

[0045] Preferably, before S3, a database of die surface quality grades and laser processing parameters is established in the computer; Among them, the die surface quality grades include surface A (Ra ≤ 0.1), surface B (0.1 < Ra ≤ 1), and surface C (1 < Ra ≤ 10), and different die surface quality grades correspond to different laser processing parameters.

[0046] In S3, the hole wall of the micro-pinhole (4) is finely processed by femtosecond laser processing technology; Based on the die surface quality grade, different laser processing parameters are selected to meet the different surface roughness requirements of the die: (3); Among them, is the arithmetic mean roughness, is the material coefficient, with a value range of 0 - 1, is the pulse frequency, is the feed rate, is the starting radius angle, is the ending radius angle, is the laser power, is the single-layer feed amount, is the defocus amount.

[0047] As an example, in the preparation process of a micro-spacing ordered densely arranged porous needle plate die according to an embodiment of the present invention, the surface quality grade of the hole wall of the micro-pinhole 4 is Ra0.1 (belonging to surface A, i.e., Ra ≤ 0.1). By matching the corresponding laser processing parameters in the computer, the laser processing parameters in the 3D metal printing roughing stage are the same as those in the above example. In the femtosecond laser finishing stage, the workpiece material is copper alloy, and the material coefficient is 0.4, the pulse frequency is 200 kHz, the starting radius angle is 5°, the feed rate is 2 mm / s, the adjusted end radius angle is 10°, the laser power is 5 W, and the single-layer feed amount is 10 , the defocus amount is 0.3 mm. Under these parameters, the micro-pinhole 4 machined has good effects and can meet the requirements of the A-level surface quality of the wall of the micro-pinhole 4. In addition, different die surface quality grades correspond to different laser processing parameters. For the C-level surface (1 < Ra ≤ 10), no femtosecond laser finishing is required.

[0048] Specifically, after the femtosecond laser finishing is completed, an integrated white light interferometer is used to perform a depth scan on the wall of the micro-pinhole 4. Three key positions, namely the entrance, the middle part, and the bottom, are selected on the wall of the micro-pinhole 4 to ensure that the detection results can cover the entire circumference of the wall. Subsequently, the interference fringes are analyzed, and the Ra value is directly output. If the detection result shows that the surface quality of the micro-pinhole 4 is A-level, it is marked as qualified, and the detection data is saved in the laser processing parameter database. If the detection result shows that the surface quality of the micro-pinhole 4 is B-level, the local femtosecond laser mechanism is triggered, and the laser processing parameters are adjusted for secondary polishing. Through the above detection and optimization process, the wall accuracy of the micro-pinhole 4 is ensured to meet the expected design requirements.

[0049] The embodiment of the present invention also discloses a porous needle plate die obtained according to the above method, as Figures 1 to 3 shown, including a bottom plate 1, positioning holes 2, connection holes 3, and micro-pinholes 4. The positioning holes 2 are distributed on the center line of the bottom plate 1, near the edge position. The connection holes 3 are distributed on the diagonal line of the bottom plate 1, near the edge position. The micro-pinholes 4 are arranged in an orderly manner in the central area of the bottom plate 1.

[0050] Specifically, positioning holes 2 are opened on the bottom plate 1 to provide precise alignment when the needle plate die is installed or cooperates with other components. The connection holes 3 are used to firmly connect the needle plate die with other structures through connecting pieces. The micro-pinholes 4 are used for clearance fit with the needle tube to adsorb diamond particles. Arranging the positioning holes 2 in this form can ensure that the die is strictly aligned with other components, improve the positioning accuracy of the needle plate die, avoid processing errors caused by assembly deviations, thereby improving the production quality, and at the same time facilitating the maintenance and replacement of the die. The design of the connection holes 3 facilitates the fixed connection of the die with other components and ensures the stability of the die during use. The micro-pinholes 4 are the core part of the die, and their accuracy and quality directly affect the forming effect of the final product. This arrangement helps to improve the processing accuracy and service performance of the micro-pinholes 4 and ensure the quality and consistency of the product.

[0051] During use, a needle-shaped fixture is formed by the mating of the micro pinholes 4 and the syringe needle clearance. The needle-shaped fixture is installed inside the cloth stone mechanism, and a negative pressure system is used to control the suction and embedding of diamond particles. In this way, the relative position accuracy between diamond particles can be controlled within ±0.05 mm, effectively ensuring that the diamond particles are accurately embedded inside the metal bond, achieving an orderly and directional arrangement of diamond particles, and greatly improving the production quality and efficiency of diamond cutting heads. The principle can be referred to in Chinese invention patent CN201610196080.1.

[0052] Refer to Figure 2 and Figure 3 As shown, among them, the cross-section of the micro pinhole 4 is circular, with a diameter of 0.15 mm, 30 rows, 61 columns, a total of 1830 holes, the adjacent row spacing and column spacing are both 0.325 mm, and the surface roughness requirement of the hole wall is Ra0.1.

[0053] That is to say, the surface roughness requirement of the hole wall of the micro pinhole 4 is Ra0.1. The smooth hole wall can reduce friction and wear, improve the durability and performance of the micro pinhole 4. At the same time, the high-precision pinhole helps to improve the processing accuracy and performance of the mold.

[0054] Specifically, according to actual needs, the diameter of the micro pinhole 4 can be changed. The micro pinhole 4 with a diameter of 0.15 mm - 0.25 mm is suitable for diamond particles between 60 / 100 meshes. Such particles are sharper, have good cutting performance, can cut into high-hardness stones, reduce chipping and improve the smoothness of the cutting surface. While the micro pinhole 4 with a diameter of 0.25 mm - 0.38 mm is suitable for diamond particles between 30 / 60 meshes. Such particles have a large exposed height, a deep cutting depth, and a high material removal rate, and are suitable for quickly cutting soft materials.

[0055] Specifically, according to actual needs, the number of rows and columns of the micro pinhole 4 can be adjusted, and different row spacings and column spacings can be designed to achieve an orderly arrangement of different shapes of the micro pinhole 4, improving the applicability of the product. For scenarios that require rapid processing, reducing the pinhole density and appropriately widening the spacing can improve the processing efficiency. While in some high-precision processing scenarios, increasing the pinhole density and narrowing the row spacing and column spacing can improve the processing accuracy. This flexible layout method enables the product to better adapt to diverse working scenarios and meet the needs of different tasks.

[0056] The above-disclosed is only a preferred embodiment of the present invention. Of course, it cannot be used to limit the scope of the rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A preparation process of a micro-pitch ordered and densely packed porous needle plate, characterized in that: The following steps are involved: S1: Design a three-dimensional model of the mold, and design a solid in the micro-pinhole area, so that each micro-pinhole in the micro-pinhole area forms a reserved hole position mark point, and set laser processing parameters according to the characteristics of the selected material and the required mold accuracy, fill the selected metal powder, and manufacture the needle plate mold blank through 3D metal printing technology; S2: heat treating the needle plate mold blank according to the performance requirements of the selected material; S3: Identify the reserved hole position marking points through machine vision and correct the positioning deviation, select different laser processing parameters according to the mold surface quality level, and finely process the inner surface of the micro pinhole in the needle plate mold blank.

2. The preparation process of the micro-spacing ordered and closely packed porous needle plate according to claim 1, characterized in that: The reserved hole position marking point is a pit with a diameter of 0.10-0.20 mm, a thickness of 0.06-0.10 mm, and a depth of 0.3-0.8 mm.

3. The preparation process of the micro-spacing ordered and closely packed porous needle plate according to claim 1, characterized in that: The laser processing parameters include molten pool area and energy density; The molten pool area is used to optimize the scanning strategy, and the molten pool area is calculated as follows: Among them, A is the molten pool area, P is the laser power, v is the scanning speed, and d is the spot diameter, which is less than or equal to half of the processing hole diameter; The energy density is used to ensure that the metal powder is fully melted and has no defects. The energy density is calculated as follows: Among them, E_effective is the energy density, σ is the absorptivity of the material to the laser, h is the layer thickness, and s is the line spacing.

4. The preparation process of the micro-spacing ordered and closely packed porous needle plate according to claim 1, characterized in that: The metal powder material is one or more of stainless steel, titanium alloy, aluminum alloy or copper alloy.

5. The preparation process of the micro-spacing ordered and closely packed porous needle plate according to claim 1, characterized in that: The heat treatment includes solution treatment and aging treatment, including the steps of: Heat the needle plate mold blank to 1000℃, keep it warm for 2 hours and then cool it quickly to improve the uniformity and hardness of the material. Then heat the needle plate mold blank to 500℃ and keep it warm for 6 hours to further improve the strength and hardness of the material.

6. The process for preparing the micro-spacing ordered closely packed porous needle plate according to claim 1, characterized in that: The method of machine vision recognition comprises: The machine vision system optimized by deep learning method monitors the array of reserved hole position marking points in real time; The correction process for positioning deviation adopts a fine-tuning algorithm based on adaptive adjustment of monomer parameters to achieve high-precision dynamic compensation.

7. The process for preparing the micro-spacing ordered closely packed porous needle plate according to claim 6, characterized in that: The step of correcting the positioning deviation comprises: S301: Scan the needle plate mold image collected from the upper left corner to the lower right corner, perform global threshold segmentation, separate non-connected areas, select the target and optimize the image in the target area, calculate the area of ​​the area to be tested, and if the area of ​​the area to be tested is greater than a predetermined value, re-segment the image, otherwise calculate the center coordinates of the reserved hole position mark point in the area to be tested; S302: performing affine transformation on the central coordinate position of the reserved hole position marking point to obtain the positioning of several actual detection areas; S303: extracting the reserved hole position mark point image and deleting the background to reduce the number of subsequent calculations; S304: Transmitting the positioning information of the reserved hole position marking points into a computer to provide accurate positioning information for subsequent laser processing.

8. The process for preparing the micro-spacing ordered closely packed porous needle plate according to claim 7, characterized in that: The deep learning method includes one of a YOLOv5 model and an SSD model.

9. The process for preparing the micro-spacing ordered closely packed porous needle plate according to claim 1, characterized in that: The mold surface quality grades include A-grade surface: Ra≤0.1, B-grade surface: 0.1<Ra≤1, and C-grade surface: 1<Ra≤10; in, is the arithmetic mean roughness, calculated as: Among them, k is the material coefficient, which ranges from 0 to 1, f is the pulse frequency, v is the feed speed, α is the starting radius angle, β is the ending radius angle, P is the laser power, d is the single layer feed amount, and Δz is the defocus amount.

10. A porous needle plate mold obtained by the preparation process of the micro-pitch ordered and closely packed porous needle plate according to any one of claims 1 to 9, characterized in that: It comprises a base plate (1), a positioning hole (2), a connection hole (3) and micro pinholes (4), wherein the positioning hole (2) is distributed on the central axis of the base plate (1) and close to the edge, the connection hole (3) is distributed on the diagonal line of the base plate (1) and close to the edge, and the micro pinholes (4) are arranged in an orderly manner in the central area of ​​the base plate (1); The micro pinholes (4) have a circular cross-section, a diameter of 0.15 mm, 30 rows, 61 columns, a total of 1830 holes, and a spacing between adjacent rows and columns of 0.325 mm.

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