A 3D reconstruction method for an additive component based on electrochemical jet

Abstract

The present invention relates to the technical field of additive manufacturing, and discloses a three-dimensional reconstruction method for an additive component based on electrochemical jet. Through a spraying device and a power supply device, electrochemical jet machining can be performed on a component to be measured fixed on a workbench. Taking the component to be measured as the anode, spraying electrolyte on the surface of a set area of the component to be measured can expose the internal material of the set area, forming an exposed area. A driving device can move the nozzle and the imaging device relative to the workbench, thereby selecting the machining area and realizing selective material removal. The base and side walls of the exposed area formed by the additive component through the above-mentioned electrochemical jet machining are composed of materials with different orientations. Thus, the three-dimensional information of the additive component can be revealed at one time without performing processing such as cutting or mechanical polishing on the component. After obtaining the three-dimensional images of the exposed area through the imaging device, these images can be three-dimensionally reconstructed through an image processing system, thereby effectively improving the detection efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a three-dimensional reconstruction device and method for an additive component based on electrochemical jetting. Background Art

[0002] Additive manufacturing technology is a technology for manufacturing solid parts by layer-by-layer accumulation based on the principle of layered manufacturing. It has the advantages of high material utilization rate, good forming effect, short production cycle, etc., and solves the process problem of rapid preparation of complex structure parts. Selective laser melting uses computer-aided design and control to locally melt a thin layer of metal powder by scanning a high-power density laser and fuse it to the previous layer to prepare a solid component, which is one of the most widely used metal additive manufacturing technologies. The repeated scanning of the laser causes the temperature to change rapidly and periodically, which will generate phase changes and residual stresses inside the material, resulting in internal defects such as pores, cracks, lack of fusion, inclusion defects, non-uniformity and anisotropy of the metal microstructure, and ultimately significantly reduce the mechanical properties of the component, especially the fatigue resistance and fracture strength, seriously affecting the service performance of the component. Therefore, it is of great significance to identify and characterize the defects and microstructures of metal additive manufacturing components to improve the component quality and process efficiency.

[0003] Currently, existing non-destructive testing methods such as ultrasonic testing, electromagnetic testing, process compensation resonance technology, and computed tomography have at least problems such as missing image information, poor anti-interference ability, time-consuming information acquisition, expensive equipment, and low detection accuracy. In some technologies, a metallographic structure corrosion technology is used to cut, mechanically polish, chemically or electrochemically etch the component, and finally obtain information through an optical or electron microscope. Direct, reliable, detailed, and high-resolution defect and microstructure information can be obtained, but this process is cumbersome and inefficient. Each single slice can only obtain limited information on a two-dimensional plane. If comprehensive internal structure information of the component needs to be obtained, slices with various surface orientations (building direction, scanning direction, tangential direction) need to be prepared to obtain information in three-dimensional space, which will greatly increase the amount of information data and processing time and is difficult to meet the high-efficiency requirements of industrial applications. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. For this purpose, the present invention provides a three-dimensional reconstruction device for an additive component based on electrochemical jetting, which can selectively remove materials from the surface of the additive component and disclose the three-dimensional information of the component at one time, improving the detection efficiency.

[0005] The present invention also provides a three-dimensional reconstruction method for an additive component based on electrochemical jetting.

[0006] A three-dimensional reconstruction device for an additive component based on electrochemical jet according to an embodiment of the first aspect of the present invention includes a frame, a jetting device, a power supply device, an imaging device, and a driving device. Among them, a workbench is arranged on the frame, and a fixture for clamping a component to be measured is arranged on the workbench; the jetting device includes a nozzle, and the nozzle faces the fixture and is used for jetting electrolyte on the surface of a set area of the component to be measured to expose the internal material of the set area and form an exposed area; the power supply device includes a power supply positive electrode and a power supply negative electrode, the power supply positive electrode is used for connecting the component to be measured, and the power supply negative electrode is used for connecting the nozzle; the imaging device is used for acquiring a surface image of the exposed area; the driving device is used for moving the nozzle and the imaging device relative to the workbench to a position corresponding to the set area of the component to be measured.

[0007] The three-dimensional reconstruction device for an additive component based on electrochemical jet according to an embodiment of the first aspect of the present invention has at least the following beneficial effects: Through the jetting device and the power supply device, electrochemical jet machining can be performed on the component to be measured fixed on the workbench. Taking the component to be measured as the anode, jetting electrolyte on the surface of a set area of the component to be measured can expose the internal material of the set area and form an exposed area. The driving device can move the nozzle and the imaging device relative to the workbench, so as to select the machining area and realize the selective removal of materials. Since the component to be measured is an additive component, the substrate and side walls of the exposed area formed by the above-mentioned electrochemical jet machining are composed of materials with different orientations. Therefore, the three-dimensional information of the additive component can be revealed at one time without performing processing such as cutting or mechanical polishing on the component. After acquiring the three-dimensional images of the exposed area through the imaging device, these images can be three-dimensionally reconstructed through an image processing system, thereby effectively improving the detection efficiency.

[0008] According to some embodiments of the present invention, the driving device includes a Y-axis driving part, a first Z-axis driving part, an X-axis driving part, and a second Z-axis driving part, where:

[0009] The Y-axis driving part is connected to the workbench and is used for driving the workbench to move along the Y-axis direction to drive the component to be measured to move along the Y-axis direction. The first Z-axis driving part is connected to the nozzle and is used for driving the nozzle to move along the Z-axis direction to approach or move away from the workbench;

[0010] The X-axis driving part is connected to the Y-axis driving part and is used for driving the Y-axis driving part to move along the X-axis direction to drive the workbench to move relative to the nozzle along the X-axis direction; alternatively, the X-axis driving part is connected to the first Z-axis driving part and is used for driving the first Z-axis driving part to move along the X-axis direction to drive the nozzle to move relative to the workbench along the X-axis direction;

[0011] The second Z-axis driving part is connected to the imaging device and is used to drive the imaging device to move along the Z-axis direction to approach or move away from the workbench;

[0012] Both the first Z-axis driving part and the second Z-axis driving part are connected to the X-axis driving part and are arranged at intervals along the X-axis direction. The X-axis driving part is used to drive the first Z-axis driving part and the second Z-axis driving part to move along the X direction, so that the nozzle and the imaging device move relative to the workbench along the X-axis direction.

[0013] According to some embodiments of the present invention, it further includes an image processing system. The image processing system is communicatively connected to the imaging device and is used to receive and process the image to perform three-dimensional reconstruction on the component to be measured.

[0014] According to some embodiments of the present invention, the nozzle is selected from a cylindrical nozzle or a waterfall slit nozzle.

[0015] An embodiment of the second aspect of the present invention provides a three-dimensional reconstruction method for an additive component based on electrochemical jet, including the following steps:

[0016] Configure the three-dimensional reconstruction device for an additive component based on electrochemical jet in the above-mentioned first aspect embodiment, fix the component to be measured on the fixture, and adjust the position of the nozzle so that the distance between the nozzle and the component to be measured is at the initial gap;

[0017] Connect the nozzle to the negative electrode of the power supply device, connect the component to be measured to the positive electrode of the power supply device, and set the constant current output mode of the power supply device;

[0018] Drive the nozzle to move relative to the component to be measured to the set area through the driving device, or drive the nozzle to move relative to the component to be measured along the set area according to a set path, and use electrochemical jet machining to spray electrolyte through the nozzle in the set area, so that the internal material in the set area is exposed to form an exposed area;

[0019] Perform electrochemical jet machining on the set area multiple times in sequence to form exposed areas with different depths on the surface of the component to be measured. After each electrochemical jet machining is completed, drive the imaging device to move relative to the component to be measured to the set area through the driving device, and obtain a three-dimensional image of the surface of the exposed area;

[0020] Electrochemical jet machining and image acquisition are performed alternately to obtain three-dimensional images of the surfaces of the exposed areas at different depths. Process the images through the image processing system to perform three-dimensional reconstruction on the component to be measured.

[0021] The three-dimensional reconstruction method of the additive component based on electrochemical jet in the second aspect embodiment of the present invention has at least the following beneficial effects: In this method, the component to be measured is used as the anode, and the electrochemical jet machining based on anode dissolution can achieve selective removal of the surface material of the component to be measured, and the electrochemical jet machining can avoid the influence of surface quality. Since the component to be measured is an additive component, the substrate and side walls of the exposed area formed after removing the material by electrochemical jet machining are composed of materials with different orientations. Therefore, the three-dimensional information of the additive component can be revealed at one time, without the need for processing such as cutting or mechanical polishing of the component, with a fast processing rate and high detection efficiency. At the same time, the surface of the component is not damaged, avoiding the loss of microstructural information of the component.

[0022] According to some embodiments of the present invention, an exposed area with a concave structure is machined and formed in the set area through the electrochemical jet machining, and the concave structure has a hemispherical surface.

[0023] According to some embodiments of the present invention, the power supply device is set to a constant current output mode, and the size of the exposed area is changed by changing the current density of the power supply device and / or the cross-sectional size of the jet orifice of the nozzle.

[0024] According to some embodiments of the present invention, after each electrochemical jet machining is completed, the component is taken out, and observed by a scanning electron microscope and electron backscatter diffraction to determine the information at the sub-micron scale of the exposed area.

[0025] According to some embodiments of the present invention, the method of alternately performing electrochemical jet machining and acquiring images includes: after each electrochemical jet machining is completed, the nozzle is moved out through the driving device and the imaging device is driven to move relative to the component to be measured to the set area to acquire three-dimensional images of the exposed area at different depths; after each image acquisition is completed, the imaging device is moved out through the driving device and the nozzle is driven to move relative to the component to be measured to the set area for electrochemical jet machining.

[0026] According to some embodiments of the present invention, the method of processing the image by an image processing system includes: sequentially importing the image into open-source image processing software, calibrating the melting trace and fusion boundary, then importing the image into visualization processing software for three-dimensional reconstruction by layer-by-layer accumulation, and then locating the pore, crack and unfused area.

[0027] The additional aspects and advantages of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0028] The following further describes the present invention in conjunction with the drawings and embodiments, where:

[0029] Figure 1 Schematic structural diagram of a three-dimensional reconstruction device for an additive component based on electrochemical jet in an embodiment of the present invention;

[0030] Figure 2 Schematic diagram of the processing principle of electrochemical jet surface treatment;

[0031] Figure 3 Schematic structural diagram of a three-dimensional reconstruction device for an additive component based on electrochemical jet in another embodiment of the present invention;

[0032] Figure 4 Schematic flowchart of an example of three-dimensional reconstruction using the method of the embodiment of the present invention;

[0033] Figure 5 Schematic diagram of the melting track on the surface of the component to be measured through the first scan;

[0034] Figure 6 Schematic diagram of the melting track on the surface of the component to be measured through the second scan;

[0035] Figure 7 Schematic diagram of the melting track on the surface of the component to be measured through the third scan;

[0036] Figure 8 An example of three-dimensional reconstruction through multiple scans;

[0037] Figure 9 Schematic diagram of the exposed area of the component to be measured;

[0038] Figure 10 For Figure 9 An example of a microstructure and defect detected on the exposed area shown;

[0039] Figure 11 For Figure 9 Another example of a microstructure and defect detected on the exposed area shown;

[0040] Figure 12 For Figure 9 Another example of a microstructure and defect detected on the exposed area shown;

[0041] Figure 13 An example of revealing the microstructure characteristics in multiple fusion layers through one scan;

[0042] Figure 14 For Figure 13 Enlarged schematic diagram of the C-C cross-section in

[0043] Reference numerals:

[0044] Workbench 100, electrolyte tank 110, fixture 120, positive power supply 200, power supply device 210, negative power supply 220, liquid supply pipeline 300, pressure gauge 310, liquid supply device 320, filter 330, electrolyte tank 340, electrolyte 350, liquid return pipeline 360, nozzle 370, imaging device 400, image processing system 410, component to be measured 500, Y-axis drive unit 600, first Z-axis drive unit 610, X-axis drive unit 620, second Z-axis drive unit 630. Detailed implementation manners

[0045] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0046] In the description of the present invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. This 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, and therefore should not be construed as a limitation of the present invention.

[0047] In the description of the present invention, the meaning of several is more than one, and the understanding of above, below, within, etc. includes the present number. If there is a description of first, second, etc., it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0048] In the description of the present invention, unless otherwise clearly defined, words such as setting, installation, connection, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0049] In the description of the present invention, the description referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0050] At present, in some technologies, non-destructive testing methods are used to identify and characterize the defects and microstructures of metal additive manufacturing components. However, they cannot directly provide detailed and high-resolution three-dimensional spatial information of the defects and microstructures, and usually have problems such as missing image information, poor anti-interference ability, time-consuming information acquisition, expensive equipment, and low detection accuracy. For example: Ultrasonic testing establishes the relationship between the orientation and size of defects and the energy magnitude of acoustic wave reflection through the change of acoustic impedance at the defect. However, the surface roughness of additive manufacturing components is too large, which is not conducive to ultrasonic testing. Electromagnetic testing uses a coil carrying an alternating current close to the component to generate induced eddy currents. The magnitude, phase, and form of the eddy currents are affected by defects, but it can only detect surface or near-surface defects of the component, and like ultrasonic testing, it cannot determine the type of defects. The process compensation resonance technology uses the change of specific resonance frequencies caused by material defects to quickly detect the pores, cracks, and lack of fusion of the component, but it cannot locate, quantify, or characterize the defects. Computed tomography uses the difference in the ray attenuation characteristics of defects and materials to scan and generate internal and external information of the component. However, the thickness of the additive manufacturing fusion layer is about 1 / 3 of the optimal X-ray resolution level, that is, the information captured by the scan includes at least the mixed information of three fusion layers, and it is only applicable to the detection of large defects, with limited detection accuracy. Existing non-destructive testing technologies are difficult to construct defect and microstructure features at the micron scale for precise three-dimensional reconstruction.

[0051] In addition, the commonly used method for revealing the internal microstructure of additive manufacturing components is the metallographic corrosion technology, which can obtain direct, reliable, detailed, and high-resolution defect and microstructure information. However, it is necessary to cut, mechanically polish, and chemically or electrochemically etch the component to obtain two-dimensional surface information layer by layer, and then composite the information in multiple orientations (build direction, scan direction, and tangential direction) to perform three-dimensional reconstruction of the component. It can reconstruct microscale or smaller microfeatures within a millimeter-scale volume, but it requires high control precision of the equipment, needs to accurately control the material removal amount of each layer, and the preparation process is cumbersome and inefficient. It may damage the internal surface during the process to add detection errors. A single slice can only obtain limited information on a two-dimensional plane. If comprehensive structural information inside the component needs to be obtained, slices with various surface orientations (build direction, scan direction, tangential direction) need to be prepared to obtain information in three-dimensional space. The amount of data required for three-dimensional reconstruction is large, which will greatly increase the amount of information data and processing time, and it is difficult to meet the high-efficiency requirements of industrial applications.

[0052] The embodiments of the present invention provide a three-dimensional reconstruction device and method for additive components based on electrochemical jet. Through the electrochemical jet surface treatment technology based on anodic dissolution, it can selectively remove materials from the surface of the additive component and expose the three-dimensional information of the additive component at one time, facilitating the acquisition of three-dimensional images, thereby improving the detection efficiency.

[0053] Figure 1 Schematic structural diagram of a three-dimensional reconstruction device for an additive component based on electrochemical jet according to an embodiment of the present invention. Refer to Figure 1 , an embodiment of the first aspect of the present invention provides a three-dimensional reconstruction device for an additive component based on electrochemical jet, including a frame, a spraying device, a power supply device 210, an imaging device 400, and a driving device. Among them, a workbench 100 is arranged on the frame, and a fixture 120 for clamping a component to be measured 500 is arranged on the workbench 100; the spraying device includes a nozzle 370, and the nozzle 370 faces the fixture 120, and is used for spraying electrolyte on the surface of a set area of the component to be measured 500 to expose the internal material of the set area and form an exposed area; the power supply device 210 includes a power supply positive electrode 200 and a power supply negative electrode 220. The power supply positive electrode 200 is used to connect the component to be measured 500, and the power supply negative electrode 220 is used to connect the nozzle 370. Therefore, through the spraying device and the power supply device 210, electrochemical jet machining can be performed on the component to be measured 500 fixed on the workbench 100. Taking the component to be measured 500 as the anode, spraying electrolyte on the surface of the set area of the component to be measured 500 can expose the internal material of the set area and form an exposed area. The driving device is used to move the nozzle 370 and the imaging device 400 relative to the workbench 100 to a position corresponding to the set area of the component to be measured 500, so as to select the processing area and realize selective material removal. The imaging device 400 is used to acquire the surface image of the exposed area and can be transmitted to an image processing system 410 for three-dimensional reconstruction.

[0054] The component to be measured 500 is an additive component manufactured by additive manufacturing technology. It can be understood that in electrochemical jet machining (EJM), a nozzle 370 with a diameter ranging from a few hundred micrometers to several tens of millimeters is used as a tool electrode. During machining, the electrolyte is sprayed onto the surface of the component to be measured 500 at a high speed, and anodic dissolution is achieved through the electrical bias between the nozzle 370 and the component to expose the internal material and generate an analysis surface, which has the characteristics of non-contact, no machining heat, no change in material properties, and high process flexibility. Figure 2 Schematic diagram of the processing principle of electrochemical jet surface treatment. Refer to Figure 2, electrochemical jet surface processing (EJSP) based on EJM can remove bulk materials in the set area of ​​additive manufacturing components, and the fusion layer with a processing depth of more than 30μm can be processed in a single time. The material removal follows Faraday's law, and the charge transfer per unit area per unit time is controllable. The resolution of EJSP can be precisely controlled in the slice. Furthermore, the current density is concentrated inside the jet and is distributed in a Gaussian shape. Therefore, the dissolution rate of the exposed area is different, and the dissolution rate of the center is greater than that of the edge. Therefore, a three-dimensional pit-shaped exposed area is formed by processing. The exposed area can have a three-dimensional hemispherical surface, so its base and sidewalls are composed of materials with different orientations, thereby revealing the three-dimensional microstructure and defects of the material at one time. At the same time, slicing at each processing depth can obtain deep information on the microstructure inside the material, which can be used for three-dimensional reconstruction of components. In addition, due to the small exposure area produced by the microscale jet, EJSP has high localization at the microscale level.

[0055] The detection means currently used, when removing or peeling materials on the component to be tested 500, has a small single-layer processing depth, forming a flat-bottomed exposed area with a two-dimensional surface. In contrast, the base and sidewalls of the exposed area formed by the electrochemical jet processing in the embodiment of the present application are composed of materials with different orientations, which can reveal the three-dimensional information of the additive component at one time, without cutting or mechanical polishing the component, etc. After the three-dimensional image of the exposed area is obtained by the imaging device 400, these images can be reconstructed in three dimensions through the image processing system 410, which can effectively improve the detection efficiency.

[0056] refer to Figure 1, in some embodiments, the driving device includes a Y-axis driving part 600 and a first Z-axis driving part 610. The Y-axis driving part 600 is connected to the workbench 100 and is used to drive the workbench 100 to move in the Y-axis direction so as to drive the component 500 to be measured to move in the Y-axis direction. The first Z-axis driving part 610 is connected to the nozzle 370 and is used to drive the nozzle 370 to move in the Z-axis direction to approach or move away from the workbench 100. Therefore, the gap between the nozzle 370 and the surface of the component 500 to be measured fixed on the workbench 100 by the fixture 120 can be adjusted, so as to obtain the required machining gap to meet the machining requirements of exposed areas with different depths. The driving device may further include an X-axis driving part 620. The X-axis driving part 620 is connected to the Y-axis driving part 600 and is used to drive the Y-axis driving part 600 to move in the X-axis direction so as to drive the workbench 100 to move relative to the nozzle 370 in the X-axis direction; or the X-axis driving part 620 is connected to the first Z-axis driving part 610 and is used to drive the first Z-axis driving part 610 to move in the X-axis direction so as to drive the nozzle 370 to move relative to the workbench 100 in the X-axis direction. Thus, the nozzle 370 can move relative to the component 500 to be measured on the workbench 100, so as to perform electrochemical jet machining on a set area according to a set route to form a required exposed area.

[0057] Reference Figure 1, in some embodiments, the driving device may further include a second Z-axis driving part 630. The second Z-axis driving part 630 is connected to the imaging device 400 and is used to drive the imaging device 400 to move in the Z-axis direction to approach or move away from the workbench 100, so as to adjust the distance between the imaging device 400 and the exposure area and focus, and be able to photograph the exposure area at different depths of the test component 500 on the workbench 100 to obtain clear and accurate three-dimensional images. Among them, the first Z-axis driving part 610 and the second Z-axis driving part 630 can move along the X-axis respectively, or the first Z-axis driving part 610 and the second Z-axis driving part 630 can move synchronously in the X-axis direction. For example, the first Z-axis driving part 610 and the second Z-axis driving part 630 are both connected to the X-axis driving part 620 and are arranged at intervals in the X-axis direction. The X-axis driving part 620 is used to drive the first Z-axis driving part 610 and the second Z-axis driving part 630 to move in the X direction, so that the nozzle 370 and the imaging device 400 move synchronously along the X-axis relative to the workbench 100. Therefore, after each spraying process of the nozzle 370 is completed, while the nozzle 370 is moved out of the exposure area by the X-axis driving part 620, the imaging device 400 can be moved to the exposure area to image the exposure area. And after each imaging is completed, while the imaging device 400 is moved out of the exposure area by the X-axis driving part 620, the nozzle 370 can be moved to the exposure area to continue the surface processing of the test component 500, realizing the alternation of surface processing and imaging processing (or observation), which can improve the processing efficiency and reduce the setting of driving parts and simplify the structure of the device.

[0058] In addition, conventionally, a three-axis manipulator is used to pick up and place the test component 500, and at least three processes including material picking, conveying, and arranging are required to complete the function switching. In contrast, in the driving device of this embodiment, the nozzle 370 for processing and the imaging device 400 for acquiring images are installed along the same axis and can move along the same axis. For example, in the above embodiment, the nozzle 370 and the imaging device 400 are installed on the X-axis and can move in the X-axis direction. Therefore, only the translational conveying in a single direction is required to convey the test component 500 and / or the imaging device 400 to achieve function switching. In the above embodiment, the first Z-axis driving part 610 and the second Z-axis driving part 630 are both connected to the X-axis driving part 620. Thus, a single movement of the X-axis driving part 620 can make the nozzle 370 and the imaging device 400 move synchronously along the X-axis, further simplifying the processing process.

[0059] Reference Figure 2 , in some embodiments, the power supply device 210 is set to a constant current output mode, and the electrolyte sprayed by the nozzle 370 impacts the component and diffuses outward in an extremely thin liquid film. Figure 2 in NO 3 - 、Na+ 、 H 2 O, H 2 represent ions and molecules in the electrolyte, S3 represents the current density distribution, S4 represents oxides, S5 represents lack of fusion, and S6 represents pores. When there is a voltage between the component and the nozzle 370, due to the thin liquid film restricting the dispersion of the current, the current density shows a Gaussian distribution in the central region of the jet impact (reference curve S3). The charge transfer space is limited, and the processing area is controllable. At the same time, the charge transfer removes the material according to Faraday's law, and the material removal rate is controllable. Thus, a three-dimensional concave-shaped exposed area can be processed and generated on the surface of the component 500 to be measured. Internal defects such as pores, cracks, lack of fusion, and oxide particles, as well as internal growth information of the metal component such as grain orientation and microstructure, can be observed in the formed hemispherical concave pit.

[0060] In some embodiments, the nozzle 370 can be selected from a cylindrical nozzle or a waterfall slit nozzle, which can be selected according to the actual processing area. Among them, the waterfall slit nozzle has a long and narrow ejection port. Compared with the cylindrical nozzle, using the waterfall slit nozzle can increase the flow cross-sectional area of the ejection port, improve the material removal rate, thereby expanding the detection area, and at the same time, the increased flow cross-sectional area avoids the blockage of the small nozzle 370. The electrolyte can be transported to the nozzle 370 through the liquid delivery pipeline 300, and the liquid delivery pipeline 300 can be connected to the electrolyte tank 340 for containing the electrolyte, so that the electrolyte required for processing can be transported to the nozzle 370.

[0061] Reference Figure 1 In some embodiments, the three-dimensional reconstruction device for additive components based on electrochemical jet of the embodiment of the present application further includes an image processing system 410. The image processing system 410 is communicatively connected to the imaging device 400 and is used to receive and process images for three-dimensional reconstruction of the component 500 to be measured. The image processing system 410 is preset with open-source image processing software ImageJ and visualization software Avizo. During application, the imaging device 400 performs three-dimensional scanning on the exposed surface after each electrochemical jet surface treatment to obtain the surface image of the exposed area, sequentially imports all the images into the software ImageJ, calibrates the melting traces and fusion boundaries, and then imports the images into the software Avizo for three-dimensional reconstruction by layer-by-layer accumulation, and finally locates the pore, crack, and lack of fusion areas. The imaging device 400 can select a laser camera, and the scanning resolution is determined by the processing depth during the electrochemical jet surface treatment. The processing depth depends on the current density and the moving speed of the nozzle 370 during electrochemical jet processing.

[0062] Reference Figure 1 , Figure 1In the illustrated embodiment, the fixture 120 is horizontally arranged so that the surface of the component 500 to be measured extends in the horizontal direction. Therefore, when the component 500 to be measured is clamped by the fixture 120, the nozzle 370 can perform jet machining on the surface of the component 500 in the vertical direction. Or, referring to Figure 3 , the fixture 120 can also be vertically arranged so that the surface of the component 500 to be measured extends in the vertical direction. The Z-axis direction is perpendicular to the surface of the component 500 to be measured. Therefore, when the component 500 to be measured is clamped by the fixture 120, the nozzle 370 can perform jet machining on the surface of the component 500 in the horizontal direction. For the surface of the component 500 to be measured extending in the vertical direction, the residue of the electrolyte on the surface of the component can be effectively avoided.

[0063] Referring to Figure 1 or Figure 3 , in some embodiments, an electrolyte tank 110 is further provided on the workbench 100. The electrolyte tank 110 is correspondingly located below the fixture 120. The electrolyte tank 110 is used to collect and discharge the electrolyte sprayed from the nozzle 370. Specifically, when the component 500 to be measured is clamped on the fixture 120 for machining, the electrolyte tank 110 can be used to collect and discharge the electrolyte sprayed from the nozzle 370. An electrolyte circulation device can also be provided. The electrolyte circulation device includes an electrolyte tank 340, a liquid supply pipeline 300, a liquid return pipeline 360, and a liquid supply device 320. The nozzle 370 is communicated with the electrolyte tank 340 through the liquid supply pipeline 300. The liquid supply device 320 is arranged on the liquid supply pipeline 300 and can be an electrolyte pump for pumping the electrolyte. A liquid discharge port can be provided on the tank wall or the tank bottom of the electrolyte tank 110. The liquid return pipeline 360 is communicated with the liquid discharge port of the electrolyte tank 110 and is used to discharge the electrolyte in the electrolyte tank 110 into the electrolyte tank 340, and can be sent into the nozzle 370 again through the liquid supply pipeline 300 to realize the circulation of the electrolyte. A filter 330 can be configured on the liquid return pipeline 360 to separate and filter the processing waste to avoid flowing into the electrolyte tank 340. An electrolyte pump can be connected to the liquid supply pipeline 300 to pump the electrolyte 350 in the electrolyte tank 340 to the nozzle 370. A pressure gauge 310 can also be provided on the liquid supply pipeline 300 to monitor the pressure in the liquid supply pipeline 300 in real time, so as to be used as a reference for adjusting the jet flow rate of the electrolyte.

[0064] An embodiment of the second aspect of the present invention provides a three-dimensional reconstruction method for an additive component based on electrochemical jet, including the following steps:

[0065] Configure the three-dimensional reconstruction device for an additive component based on electrochemical jet in the above-mentioned embodiment of the first aspect (referring to Figures 1 to 3 ), fix the component 500 to be measured on the fixture 120, and adjust the position of the nozzle 370 so that the distance between the nozzle 370 and the component 500 is in the initial gap;

[0066] Connect the nozzle 370 to the negative power terminal 220 of the power supply device 210, connect the component to be measured to the positive power terminal 200 of the power supply device 210, and set the constant current output mode of the power supply device 210;

[0067] Drive the nozzle 370 to move relative to the component to be measured 500 to a set area by a driving device, or drive the nozzle 370 to move relative to the component to be measured 500 along a set path in a set area, and use electrochemical jet machining to spray electrolyte through the nozzle 370 in the set area to expose the internal material in the set area to form an exposed area;

[0068] Perform electrochemical jet machining on the set area multiple times in sequence to form exposed areas with different depths on the surface of the component to be measured 500. After each electrochemical jet machining is completed, drive the imaging device 400 to move relative to the component to be measured 500 to the set area by a driving device to obtain a three-dimensional image of the surface of the exposed area;

[0069] The electrochemical jet machining and image acquisition are performed alternately to obtain three-dimensional images of the surfaces of the exposed areas at different depths, and the images are processed by the image processing system 410 to perform three-dimensional reconstruction on the component to be measured 500.

[0070] Adopt the above three-dimensional reconstruction method of an additive component based on electrochemical jet. With the component to be measured 500 as the anode, the electrochemical jet machining based on anodic dissolution can achieve selective removal of the surface material of the component to be measured 500, and the electrochemical jet machining can avoid the influence of surface quality. Since the component to be measured 500 is an additive component, the base and side walls of the exposed area formed after removing the material by electrochemical jet machining are composed of materials with different orientations. Thus, the three-dimensional information of the additive component can be revealed at one time without performing processing such as cutting or mechanical polishing on the component, with a fast processing rate and high detection efficiency. At the same time, the surface of the component is not damaged, avoiding the loss of the microstructural information of the component.

[0071] In some embodiments, an exposed area with a concave structure is machined in the set area by electrochemical jet machining, and the concave structure has a hemispherical surface. The relative movement of the component to be measured 500 and the nozzle 370 can be controlled by a driving device to detect the target area on the surface of the component along a specific path. Among them, the moving speed of the nozzle 370 relative to the component can be selected as 0.1 mm / s to 2 mm / s.

[0072] During electrochemical jet machining, the current density and the jet diameter ejected from the nozzle 370 jointly determine the size of the electrochemical jet surface treatment area. In the methods of some embodiments of the present invention, the power supply device 210 is set to a constant current output mode, and the size of the exposed area is changed by changing the current density of the power supply device 210 and / or the cross-sectional size of the ejection orifice of the nozzle 370. In the methods of embodiments of the present invention, the electrolyte can be an aqueous solution of NaNO3 with a mass fraction of 15% to 30%, and the average flow rate of the electrolyte can be set to 10 to 15 m / s; the nozzle 370 can use a cylindrical nozzle or a waterfall slit nozzle, and the inner diameter of the cylindrical nozzle can be selected from 0.1 mm to 1.43 mm; during processing, the initial gap between the nozzle 370 and the component to be measured 500 can be adjusted to 200 μm to 500 μm; the power supply device 210 selects a constant current mode, and the current density can be set to 20 A / cm 2 ~300 A / cm 2 , so as to process and form an exposed area with an appropriate depth.

[0073] In some embodiments, after each electrochemical jet machining is completed, the component is taken out, and observations are made by a scanning electron microscope and electron backscatter diffraction to determine sub-micron scale information of the exposed area, such as sub-micron scale information such as unit cells and grain orientations.

[0074] In some embodiments, the method of alternately performing electrochemical jet machining and acquiring images includes: after each electrochemical jet machining is completed, the nozzle 370 is moved out by a driving device and the imaging device 400 is driven to move relative to the component to be measured 500 to a set area to acquire three-dimensional images of the exposed area at different depths; after each image acquisition is completed, the imaging device 400 is moved out by the driving device and the nozzle 370 is driven to move relative to the component to be measured 500 to a set area for electrochemical jet machining. Among them, a laser camera can be used to complete the characterization of the three-dimensional microstructure of the exposed surface. The scanning resolution is determined by the machining depth during electrochemical jet surface treatment, and the machining depth depends on the current density during machining and the moving speed of the nozzle 370.

[0075] In some embodiments, the image processing system 410 is preset with open-source image processing software ImageJ and visualization software Avizo. The method of processing images by the image processing system 410 includes: sequentially importing all images into the software ImageJ, calibrating the melting traces and fusion boundaries, and then importing the images into the software Avizo for layer-by-layer accumulation for three-dimensional reconstruction, and finally locating pores, cracks and unfused areas.

[0076] In the above embodiments, the component 500 to be measured is a selective laser melting additive manufacturing component, selected from at least one of aluminum alloy, stainless steel or other alloys; before surface machining of the component 500 to be measured, pretreatment can be carried out: ultrasonic degreasing treatment is carried out in acetone and ethanol in sequence, then it is cleaned with deionized water and dried using compressed air.

[0077] Figure 4 FIG. 4 is a schematic flow chart of an example of performing three-dimensional reconstruction by using the method of the embodiment of the present invention. The following provides an example of performing three-dimensional reconstruction on an AlSi 10 Mg additive component by using the method of the above embodiments of the present invention. Among them, Figures 5 to 7 FIG. 8 is a schematic diagram of the melting track after sequential scanning of the surface of the component 500 to be measured. Figure 8 FIG. 10 is an example of performing three-dimensional reconstruction by multiple scans. Figure 9 FIG. 12 is a schematic diagram of the exposed area of the component 500 to be measured. Figures 10 to 12 For Figure 9 FIG. 16 is an example of several microstructures and defects detected on the exposed area shown in FIG. Figure 13 FIG. 18 is an example of revealing the microstructural characteristics within multiple fusion layers by one scan. Figure 14 For Figure 13 FIG. 22 is an enlarged schematic diagram of the C-C cross section in FIG. Figures 4 to 13 :

[0078] In the first step, the component 500 to be measured is a selective laser melting AlSi 10 Mg additive component with a diameter of 30 mm and a thickness of 3 mm. A laser camera is used, and the laser scanning strategy is a two-way scan with a 67 o ° rotation layer by layer, and the layer thickness is 30 μm. The component 500 to be measured is subjected to ultrasonic degreasing treatment in acetone and ethanol in sequence, then cleaned with deionized water and dried using compressed air. The component 500 to be measured is clamped by a fixture 120 and accurately positioned on the workbench 100, above the electrolyte tank 110. The device nozzle 370 selects a cylindrical nozzle, and the inner diameter is selected to be 0.4 mm. The nozzle 370 is connected to the liquid delivery pipeline 300, and the X-axis position is adjusted so that the nozzle 370 maintains an initial gap of 500 μm from the component 500 to be measured.

[0079] In the second step, the nozzle 370 is connected to the negative electrode 220 of the power supply, the component 500 to be measured is connected to the positive electrode 200 of the power supply, the power supply device 210 is set to a constant current output mode, the current density is 200 A / cm 2 , the current waveform is direct current, and an oscilloscope current probe is used to obtain the current signal. The selected electrolyte is an aqueous solution of 20% mass fraction of NaNO 3 .

[0080] In the third step, turn on the power supplies of the electrolyte pump and the driving device, so that the electrolyte is sprayed onto the surface of the component through the nozzle 370, and adjust the electrolyte pressure to control the average flow velocity of the electrolyte to be 13 m / s.

[0081] In the fourth step, start the power supply device 210 to perform electrochemical jet machining on the surface of the component to be measured 500. Start the power supply of the driving device, and drive the nozzle 370 to scan along the set path in the X direction at a speed of 2 mm / s.

[0082] In the fifth step, after the machining is completed, turn off the power supply device 210 and turn off the electrolyte pump.

[0083] In the sixth step, use the driving device to move the nozzle 370 out, move the imaging device 400 to the machining position of the component, take an image of the surface of the exposed area of the component and transmit the image to the image processing software ImageJ to calibrate the melting traces and the fusion boundary. The driving device moves the imaging device out and moves the nozzle 370 to the opposite side of the component.

[0084] In the seventh step, repeat steps three, four, five, and six to obtain information at different depths on the surface of the component. Import the calibrated images into the software Avizo in sequence to perform three-dimensional reconstruction of the component layer by layer, and locate the pores, cracks, and unfused areas.

[0085] As Figures 5 to 8 shown, electrochemical jet machining is performed on two regions A and B of the component to be measured 500. The single scan depth is 7 μm. By performing multiple scans, the three-dimensional microstructure of the component can be obtained. The image is obtained by a scanning electron microscope. Among them, the 20 μm marked in the lower right corner is the scale. Figure 5 is a schematic diagram of the melting trajectory on the surface of the component to be measured 500 after the first scan, S1-A-1 st represents the melting trajectory obtained by the first scan of region A on the surface of the component to be measured 500. At this time, region B on the surface of the component to be measured 500 is not yet exposed; Figure 6 is a schematic diagram of the melting trajectory on the surface of the component to be measured 500 after the second scan, S1-A-2 nd represents the melting trajectory obtained by the second scan of region A on the surface of the component to be measured 500, S1-B-1 st represents the melting trajectory obtained by the first scan of region B on the surface of the component to be measured 500; Figure 7 is a schematic diagram of the melting trajectory on the surface of the component to be measured 500 after the third scan, S1-A-3 rd represents the melting trajectory obtained by the third scan of region A on the surface of the component to be measured 500, S1-B-2 nd represents the melting trajectory obtained by the second scan of region B on the surface of the component to be measured 500; Figure 8As an example of three-dimensional reconstruction of the acquired image after the above-mentioned multiple scans, where S1-A represents the structural schematic of three-dimensional reconstruction of the melting track obtained by three scans of the A area on the surface of the component 500 to be measured, and S1-B represents the structural schematic of three-dimensional reconstruction of the melting track obtained by two scans of the B area on the surface of the component 500 to be measured.

[0086] If the power supply of the driving device is not started in the fourth step, a hemispherical pit (exposed area) can be obtained by taking out the component in the fifth step after 4.5 s of processing and observing it with a scanning electron microscope. As Figure 9 shown, the material microstructure such as the melting track and the fusion boundary can be clearly identified, and the micron-level defects inside the material such as oxides, pores, and lack of fusion can be effectively detected. Among them, Figure 10 is the structural schematic of the oxide S4 identified in the exposed area, and the lower right corner Figure 11 is the structural schematic of the lack of fusion S5 identified in the exposed area, Figure 12 is the structural schematic of the pore S6 identified in the exposed area. Figures 9 to 12 The marked 100 μm, 10 μm, and 5 μm in the lower right corner are scales.

[0087] If the scanning speed is reduced to 0.1 mm / s in the fourth step, the material dissolution depth increases. After a single scan, the workpiece is taken out in the fifth step and observed with a scanning electron microscope. As Figure 13 and Figure 14 shown, the surface dissolution depth is 130 μm, exceeding multiple fusion layers of additive manufacturing, and the information of multiple layers of volume can be revealed at one time. Among them, ∠67 o represents the observation using the scanning strategy of rotating layer by layer by ∠67 o . The marked 100 μm in the lower right corner is the scale, X (μm) represents the coordinate in the X direction of the component 500 to be measured, with the unit of μm, and Z (μm) represents the coordinate in the Z direction of the component 500 to be measured, with the unit of μm.

[0088] As can be seen from the above embodiments, compared with the currently commonly used test schemes, the three-dimensional reconstruction device and method of additive components based on electrochemical jet in the above embodiments of the present invention can disclose three-dimensional information at one time, greatly improving the detection efficiency. Moreover, the surface topography information obtained by layer-by-layer scanning processing of the electrochemical jet surface treatment technology can be used for the three-dimensional reconstruction of the microstructure of additive manufacturing components. In addition, the electrochemical jet processing equipment is simple and can achieve low-cost processing, and at the same time, selective removal of materials can be realized. The electrochemical jet surface treatment has no contact with the component, which can avoid the influence on the surface quality. The processing removal depth can be regulated by the current density, the detection resolution is adjustable, and the detection accuracy is high. The removal shape is a three-dimensional hemisphere, which can disclose the three-dimensional information of the component at one time, with a fast processing rate and high detection efficiency. At the same time, the surface of the component is not damaged and the microstructure information of the component is not missing. The three-dimensional reconstruction device and method of additive components based on electrochemical jet in the embodiments of the present invention are applicable to universities or factory laboratories, and can provide an efficient and accurate detection and verification scheme for additive components, thereby providing a favorable basis for optimizing the additive manufacturing design or process of components, facilitating the reduction of internal defects, and improving production efficiency and quality.

[0089] The above has described the embodiments of the present invention in detail with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art in the technical field to which the present invention pertains, various changes can be made without departing from the gist of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. Three-dimensional reconstruction method for additive manufacturing components based on electrochemical jet, characterized in that, it includes the following steps: Configure a three-dimensional reconstruction device for additive manufacturing components based on electrochemical jet. The three-dimensional reconstruction device includes a frame, a spraying device, a power supply device, an imaging device, and a driving device. A workbench is provided on the frame, and a fixture for clamping the component to be measured is provided on the workbench; the spraying device includes a nozzle, the nozzle faces the fixture, and is used to spray electrolyte on the surface of the set area of the component to be measured to expose the internal material of the set area, forming an exposed area; the power supply device includes a power supply positive electrode and a power supply negative electrode, the power supply positive electrode is used to connect the component to be measured, and the power supply negative electrode is used to connect the nozzle; the imaging device is used to obtain the surface image of the exposed area; the driving device is used to move the nozzle and the imaging device relative to the workbench to the set area corresponding to the component to be measured; Fix the component to be measured on the fixture, and adjust the position of the nozzle so that the distance between the nozzle and the component to be measured is at the initial gap; Connect the nozzle to the power supply negative electrode of the power supply device, connect the component to be measured to the power supply positive electrode of the power supply device, and set the constant current output mode of the power supply device; Drive the nozzle to move relative to the component to be measured to the set area through the driving device, or drive the nozzle to move relative to the component to be measured along the set area according to a set path, and use electrochemical jet machining to spray electrolyte through the nozzle in the set area to expose the internal material of the set area to form an exposed area; Perform electrochemical jet machining on the set area multiple times in sequence to form exposed areas with different depths on the surface of the component to be measured. After each electrochemical jet machining is completed, drive the imaging device to move relative to the component to be measured to the set area through the driving device to obtain the three-dimensional image of the surface of the exposed area; Electrochemical jet machining and image acquisition are alternated to obtain three-dimensional images of the surfaces of the exposed areas at different depths, and the images are processed by an image processing system to perform three-dimensional reconstruction on the component to be measured.

2. The three-dimensional reconstruction method for additive manufacturing components based on electrochemical jet according to claim 1, characterized in that, An exposed area with a concave structure is processed and formed in the set area through the electrochemical jet machining, and the concave structure has a hemispherical surface.

3. The three-dimensional reconstruction method for additive manufacturing components based on electrochemical jet according to claim 1, characterized in that, Set the power supply device to the constant current output mode, and change the size of the exposed area by changing the current density of the power supply device and / or the cross-sectional size of the spraying orifice of the nozzle.

4. The three-dimensional reconstruction method for additive manufacturing components based on electrochemical jet according to claim 1, characterized in that, After each electrochemical jet machining is completed, take out the component and observe it through a scanning electron microscope and electron backscatter diffraction to determine the information at the sub-micron scale of the exposed area.

5. The three-dimensional reconstruction method of the additive component based on electrochemical jet according to claim 1, characterized in that, the method of alternately performing electrochemical jet machining and acquiring images includes: after each electrochemical jet machining is completed, moving the nozzle out by the driving device and driving the imaging device to move relative to the component to be measured to the set area to acquire three-dimensional images of the exposed area at different depths; after each image acquisition is completed, moving the imaging device out by the driving device and driving the nozzle to move relative to the component to be measured to the set area for electrochemical jet machining.

6. The three-dimensional reconstruction method of the additive component based on electrochemical jet according to any one of claims 1 to 5, characterized in that, the method of processing the images by the image processing system includes: sequentially importing the images into open-source image processing software, calibrating the melting traces and fusion boundaries, then importing the images into visualization processing software for three-dimensional reconstruction by layer-by-layer accumulation, and then locating the pores, cracks and unfused areas.

Images