A 3D printing device and method based on cold cathode CT

Abstract

The application discloses a kind of 3D printing device and method based on cold cathode CT.The 3D printing device includes: printer body, vertical direction X-ray detection module, horizontal direction X-ray detection module, connecting frame and system control module;Vertical direction X-ray detection module and horizontal direction X-ray detection module include cold cathode bulb and X-ray imaging detector;Vertical direction X-ray detection module is set in the direct upper of printer body by 3D printer connecting frame, emits and collects the X-ray of vertical direction penetration target object;Horizontal direction X-ray detection module is embedded and set on the printer body, emits and collects the X-ray of horizontal direction penetration target object.A kind of non-contact, fast and efficient online detection device is realized, real-time detects the defect and error generated in metal 3D printing process, and improves the beneficial effect of quality control and process.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, and more specifically, relates to a 3D printing device and method based on cold cathode CT. Background Technology

[0002] Additive manufacturing technology, commonly known as 3D printing technology, has significant advantages over traditional manufacturing methods in areas such as complex parts manufacturing, integrated manufacturing, and personalized customization. It is widely used in aerospace, automotive manufacturing, and medical and health fields.

[0003] Metal 3D printing technology involves complex and varied processes, with numerous factors affecting print quality, making it difficult to avoid printing defects. The most common defects are voids and gaps between the printed mesh, which severely impact the overall mechanical properties of the workpiece. For industries with stringent quality requirements, such as aerospace, automotive manufacturing, and medical devices, quality control is a critical challenge that metal 3D printing technology must address.

[0004] Currently, in the field of metal 3D printing, existing online inspection technologies mainly include ultrasonic testing and scanning electron microscopy (SEM). However, ultrasonic testing is primarily applied to workpieces with simple structures, and the surface roughness of the workpiece directly affects the inspection accuracy. Ultrasonic testing has an accuracy of tens to hundreds of micrometers, while the resolution required for defect detection in metal 3D printing is generally less than 6.3 micrometers. For metal 3D printed workpieces, ultrasonic testing cannot meet the surface roughness requirements. As for SEM, its detection depth is generally no more than 5 micrometers, but the mesh resolution of metal 3D printing is 20 to 100 micrometers, making it difficult for SEM to detect defects such as voids and gaps between the meshes. Furthermore, existing technologies utilize X-rays for defect detection; however, this only allows for two-dimensional planar defect detection and cannot reconstruct a three-dimensional model for three-dimensional defect detection, resulting in insufficient accuracy. Therefore, existing inspection technologies cannot accurately identify defects generated during the metal 3D printing process. Summary of the Invention

[0005] In view of the shortcomings of related technologies, the purpose of this invention is to provide a 3D printing device and method based on cold cathode CT, which aims to solve the problem that existing detection technologies cannot accurately identify defects generated during the metal 3D printing process.

[0006] To achieve the above objectives, the present invention provides a 3D printing device based on cold cathode CT, comprising: a printer body, a vertical X-ray detection module, a horizontal X-ray detection module, a connecting frame, and a system control module; The vertical X-ray detection module includes a vertical cold cathode tube and a vertical X-ray imaging detector; the vertical cold cathode tube is positioned directly above the printer body via the connecting frame and is used to emit vertical X-rays onto the printing platform; the vertical X-ray imaging detector is positioned below the printing platform and is used to collect vertical X-rays that penetrate the target object; the printing platform is located inside the printer body and is used to place the generated target object. The horizontal X-ray detection module includes a horizontal cold cathode tube and a horizontal X-ray imaging detector, which are embedded in the printer body. The horizontal X-ray imaging detector and the horizontal cold cathode tube are symmetrically arranged about the printing platform. The horizontal cold cathode tube is used to emit horizontal X-rays to the printing platform, and the horizontal X-ray imaging detector is used to collect horizontal X-rays that penetrate the target object. The system control module is used to control the laser source on the printer body to 3D print the target object on the printing platform, and simultaneously control the printing platform to move at a constant speed along the Y direction; it is also used to control the vertical cold cathode tube and the horizontal cold cathode tube to emit X-rays to the printing platform, and to acquire the signals collected by the horizontal X-ray imaging detector and the vertical X-ray imaging detector, so as to reconstruct the three-dimensional model of the target object through X-ray tomography.

[0007] Optionally, the vertical X-ray detection module further includes a vertical X-ray collimator and a vertical collimator fixing bracket; the vertical collimator fixing bracket is used to support and fix the vertical cold cathode tube and the vertical X-ray collimator; the conical beam generated by the vertical cold cathode tube is aligned with the center of the vertical X-ray collimator, and the vertical X-ray collimator is used to collimate the conical beam into a fan-shaped beam; The horizontal X-ray detection module also includes a horizontal X-ray collimator and a horizontal collimator fixing bracket; the horizontal collimator fixing bracket is used to support and fix the horizontal cold cathode tube and the horizontal X-ray collimator; the conical beam generated by the horizontal cold cathode tube is aligned with the center of the horizontal X-ray collimator, and the horizontal X-ray collimator is used to collimate the conical beam into a fan-shaped beam.

[0008] Optionally, the system control module includes a main control server, a printing control system submodule, and an X-ray control system submodule; The printing control system submodule is used to control the laser source on the printer body to 3D print the target object on the printing platform, and at the same time control the printing platform to move at a constant speed along the Y direction. The X-ray control system submodule is used to control the vertical and horizontal cold cathode tubes to emit X-rays onto the printing platform. The main control server acquires signals from the horizontal and vertical X-ray imaging detectors to reconstruct a three-dimensional model of the target object using X-ray tomography. It is also used to control the printing control system submodule and the X-ray control system submodule via control signals.

[0009] Optionally, the metal 3D printer body includes a printer frame, a printing platform, a laser source, a powder spreading device, and an X-direction printing transmission structure, a Y-direction printing transmission structure, and a Z-direction printing transmission structure disposed on the printer frame. The printing platform includes a printing substrate and a Y-direction scanning transmission structure; the powder spreading device is fixed on the printer frame and installed above the printing substrate, and is used to hold metal powder and spread and level it on the printing substrate; The X-direction printing transmission structure and the Y-direction printing transmission structure are used to drive the laser source to move and select areas on the printing substrate, and the Z-direction printing transmission structure is used to drive the printing substrate to move up and down in the Z direction. The Y-direction scanning transmission structure is used to drive the printing substrate to move at a constant speed along the Y direction.

[0010] Optionally, the print control system submodule includes a print control chassis and a print control display; The print control display is used to receive external commands to control the print control chassis; The printing control chassis is installed at the bottom of the printer frame and is used to control the power of the laser source, the movement of the powder spreading device, the movement of the X-direction printing transmission structure, the movement of the Y-direction printing transmission structure, the movement of the Z-direction printing transmission structure, and the movement of the Y-direction scanning transmission structure during the 3D printing process.

[0011] Optionally, the main control server is also used to detect and analyze the size error and lattice defect of the 3D printed object in real time based on the reconstructed 3D model, and to control the printing control system submodule and the x-ray control system submodule through feedback.

[0012] Optionally, the printing control system submodule is used to adjust the power of the laser source or the single-point printing time.

[0013] In a second aspect, the present invention also provides a 3D printing method based on cold cathode CT, performed using a 3D printing apparatus as described in any of the first aspects, comprising: Initialize the 3D printing device; The system control module controls the laser source to 3D print the target object on the printing platform, and simultaneously controls the printing platform to move at a constant speed along the Y direction; The system control module controls the vertical and horizontal cold cathode tubes to emit X-rays onto the printing platform from the vertical and horizontal directions, respectively, and acquires the signals collected by the horizontal and vertical X-ray imaging detectors to reconstruct a three-dimensional model of the target object through X-ray tomography.

[0014] Compared with the prior art, the above-described technical solutions conceived in this invention can achieve the following beneficial effects: 1. This invention provides a 3D printing device based on cold cathode CT. The device uses vertical and horizontal X-ray detection modules to irradiate the printed object in the printing area with X-rays in the vertical and horizontal directions. The printing control system moves the printing area at a constant speed along the Y-axis to achieve X-ray tomographic imaging, reconstructing a three-dimensional model of the printed object. The reconstructed 3D model is then used to detect dimensional errors and lattice defects in the printed object. The X-ray imaging detector can achieve a detection accuracy of tens of micrometers. This embodiment of the 3D printing device is equipped with vertical and horizontal X-ray modules, providing a non-contact, fast, efficient, and high-precision online detection device. This enables real-time detection of lattice defects and dimensional errors generated during metal 3D printing, and feedback control of 3D printing activities improves quality control and process efficiency.

[0015] 2. This invention provides a 3D printing device based on cold cathode CT, which uses a cold cathode X-ray tube as an X-ray source. Traditional hot cathode electron guns are characterized by high cost, complex structure, and bulky size. Since the cathode needs to be heated, it takes a long time to reach the working temperature, making it difficult to achieve rapid start-up. In this embodiment, a cold cathode X-ray tube is used to generate an X-ray source. The main material used is a cold cathode X-ray tube with a coniferous tree-shaped carbon nanotube structure. During use, a high-voltage pulse is applied by controlling the boost circuit to instantly excite X-rays without the need for preheating. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a 3D printing device based on cold cathode CT provided by the present invention; Figure 2 This is a schematic diagram of the structure of the metal 3D printer body in this invention; Figure 3 This is a schematic diagram of the printing platform in this invention; Figure 4 This is a schematic diagram of the powder spreading device in this invention; Figure 5 This is a schematic diagram of the printing control system in this invention; Figure 6 This is a schematic diagram of the vertical X-ray detection module in this invention; Figure 7 This is a schematic diagram of the system control module in this invention.

[0017] Figure label: 1: Printer body; 2: Vertical X-ray detection module; 3: Horizontal X-ray detection module; 4: Connecting frame; 11: Printing platform; 12: Laser source; 13: Toner spreading device; 14: X-axis printing transmission structure; 15: Y-axis printing transmission structure; 16: Z-axis printing transmission structure; 17: Printing control system submodule; 18: Printer frame; 21: Vertical cold cathode X-ray tube; 22: Vertical X-ray collimator; 23: Vertical collimator mounting bracket; 24: Vertical X-ray field; 25: Vertical X-ray imaging detector; 31: Horizontal cold cathode X-ray tube; 32: Horizontal X-ray collimator; 33: Horizontal collimator mounting bracket; 34: Horizontal X-ray field; 35: Horizontal X-ray imaging detector; 111: Printing substrate; 112: Y-axis scanning transmission structure; 131: Toner spreading box; 132: Toner spreading box transmission structure; 171: Printing control chassis; 172: Printing control display. 51: Main control server; 52: Printing control system software; 53: X-ray control system software; 54: Motion control; 55: Laser control; 56: Vertical X-ray control; 57: Horizontal X-ray control. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0019] The following description, in conjunction with a preferred embodiment, illustrates the content involved in the above embodiments.

[0020] Example 1 like Figure 1 As shown, a 3D printing device based on cold cathode CT includes: a printer body 1, a vertical X-ray detection module 2, a horizontal X-ray detection module 3, a connecting frame 4, and a system control module. The vertical X-ray detection module 2 includes a vertical cold cathode tube 21 and a vertical X-ray imaging detector 25; the vertical cold cathode tube 21 is positioned directly above the printer body 1 via the connecting frame 4, and is used to emit vertical X-rays to the printing platform 11; the vertical X-ray imaging detector 25 is positioned below the printing platform 11, and is used to collect vertical X-rays that penetrate the target object; the printing platform 11 is located in the printer body 1 and is used to place the generated target object; Each of the horizontal X-ray detection modules 3 includes a horizontal cold cathode tube 31 and a horizontal X-ray imaging detector 35, which are embedded in the printer body 1. The horizontal X-ray imaging detector 35 and the horizontal cold cathode tube 31 are symmetrically arranged about the printing platform 11. The horizontal cold cathode tube 31 is used to emit horizontal X-rays to the printing platform 11, and the horizontal X-ray imaging detector 35 is used to collect horizontal X-rays that penetrate the target object. The system control module is used to control the laser source 12 on the printer body 1 to perform 3D printing of the target object on the printing platform 11, and simultaneously control the printing platform 11 to move at a constant speed along the Y direction; it is also used to control the vertical cold cathode tube 21 and the horizontal cold cathode tube 31 to emit X-rays to the printing platform 11, and to acquire the signals collected by the horizontal X-ray imaging detector 35 and the vertical X-ray imaging detector 25, so as to reconstruct the three-dimensional model of the target object through X-ray tomography.

[0021] The main control server controls the printing control submodule and the X-ray control system submodule. When the 3D printing device is performing metal 3D printing, the printing control system submodule 17 controls the powder spreading device to spread a layer of metal powder on the printing platform 11. The printing control system submodule 17 controls the printing transmission mechanism to drive the laser source 12 to print the metal powder on the printing platform 11 according to the preset trajectory. After one layer is printed, the printing control system submodule 17 controls the powder spreading device and the laser source 12 to return to the initial position. The X-ray control system software 53 controls the vertical X-ray detection module 2 and the horizontal X-ray detection module 3 to emit X-rays from the vertical and horizontal directions to the printing platform 11 for X-ray tomography imaging. Specifically, it includes: (1) The vertical cold cathode tube 21 on the vertical X-ray detection module 2 emits vertical X-rays to the printing platform 11, and the vertical X-ray imaging detector 25 collects the vertical X-rays that penetrate the target object; (2) The horizontal cold cathode tube 31 on the horizontal X-ray detection module 3 emits horizontal X-rays to the printing platform 11, and the horizontal X-ray imaging detector 35 collects the horizontal X-rays that penetrate the target object; (3) The printing control system submodule 17 controls the printing platform 11 to move at a constant speed along the Y direction; (4) The main control server 51 collects the signals from the vertical X-ray imaging detector 25 and the horizontal X-ray imaging detector 35, and reconstructs the three-dimensional model of the 3D printed object through X-ray tomography imaging. To achieve X-ray tomography, the object under test needs to be irradiated by rotating X-rays on a single axis. Based on the different absorption capacity (or radiodensity) of the object to X-rays, a three-dimensional image of the cross-section is reconstructed. After window value and window level processing, a relative grayscale image can be obtained. The images are then stacked using computer software to form a stereoscopic image. However, simultaneously moving the vertical X-ray detection module 2 and the horizontal X-ray detection module 3 is complex and prone to errors. Therefore, in this embodiment, the printing control system submodule 17 controls the printing platform 11 to move at a constant speed along the Y direction, so that the vertical and horizontal X-rays can fully scan the printing platform 11. Furthermore, in this embodiment, all X-ray detection modules adopt a backscattering structure, which reduces the overall size of the device.

[0022] Furthermore, the main control server is also used to detect and analyze the dimensional errors and lattice defects of the 3D printed object in real time based on the reconstructed 3D model. It then uses feedback control of the printing control system submodule 17 and the X-ray control system submodule to adjust the powder spreading device and laser source 12, thereby supplementing the printing process. The X-ray control system submodule then performs another inspection, and only after the errors meet the accuracy requirements is the next layer printed. The specific operations of the printing control system submodule 17 include adjusting the laser source power or the single-point printing time.

[0023] Optionally, the vertical X-ray detection module further includes a vertical X-ray collimator and a vertical collimator fixing bracket; the vertical collimator fixing bracket is used to support and fix the vertical cold cathode tube and the vertical X-ray collimator; the conical beam generated by the vertical cold cathode tube is aligned with the center of the vertical X-ray collimator, and the vertical X-ray collimator is used to collimate the conical beam into a fan-shaped beam; The horizontal X-ray detection module also includes a horizontal X-ray collimator and a horizontal collimator fixing bracket; the horizontal collimator fixing bracket is used to support and fix the horizontal cold cathode tube and the horizontal X-ray collimator; the conical beam generated by the horizontal cold cathode tube is aligned with the center of the horizontal X-ray collimator, and the horizontal X-ray collimator is used to collimate the conical beam into a fan-shaped beam.

[0024] like Figure 6 As shown, taking the vertical X-ray detection module 2 as an example, the vertical X-ray detection module 2 includes: a vertical cold cathode tube 21, a vertical X-ray collimator 22, a vertical collimator fixing bracket 23, and a vertical X-ray imaging detector 25. The vertical collimator fixing bracket 23 is used to support and fix the vertical cold cathode tube 21 and the vertical X-ray collimator 22. The vertical cold cathode tube 21 generates a conical beam, aligned with the center of the vertical X-ray collimator 22. The vertical X-ray collimator 22 has a slit at its center, which collimates the X-rays into a fan-shaped beam, such as... Figure 6 As shown, the vertical X-ray field 24 is fan-shaped; the vertical X-ray imaging detector 25 is installed below the printed substrate to collect X-rays that penetrate vertically through the object being inspected.

[0025] Similarly, the horizontal X-ray detection module includes a horizontal cold cathode tube, a horizontal X-ray collimator, a horizontal collimator mounting bracket, and a horizontal X-ray imaging detector; its working principle is similar to that of the vertical X-ray detection module, and will not be described in detail here.

[0026] Optional, such as Figure 2 As shown, the printer body 1 includes a printer frame 18, a printing platform 11, a laser source 12, a powder spreading device 13, and an X-direction printing transmission structure 14, a Y-direction printing transmission structure 15 and a Z-direction printing transmission structure 16 disposed on the printer frame 18. The printing platform 11 includes a printing substrate 111 and a Y-direction scanning transmission structure 112; the powder spreading device 13 is fixed on the printer frame 18 and installed above the printing substrate 111, and is used to hold metal powder and spread and level it on the printing substrate 111. The X-direction printing transmission structure 14 and the Y-direction printing transmission structure 15 are respectively used to drive the laser source 12 to move and select areas on the printing substrate 111, and the Z-direction printing transmission structure 16 is used to drive the printing substrate 111 to move up and down in the Z direction. The Y-direction scanning transmission structure 112 is used to drive the printing substrate 111 to move at a constant speed along the Y direction.

[0027] The printing substrate 111 is a substrate used for metal 3D printing; powder spreading and printing both take place on the printing substrate 111. The laser source 12 can generate a high-power laser for melting or sintering metal powder; such as... Figure 4 As shown, the powder spreading device 13 includes a powder spreading box 131 and a powder spreading box transmission structure 132. The powder spreading device 13 is installed above the printing substrate 111 and is used to hold metal powder and spread and level it on the printing substrate 111. The X-direction printing transmission structure 14 and the Y-direction printing transmission structure 15 drive the laser source 12 to move and select areas in the X and Y directions. The Z-direction printing transmission structure 16 drives the printing platform to move up and down in the Z direction to realize layer changing powder spreading and printing.

[0028] When the vertical X-ray detection module 2 and the horizontal X-ray detection module 3 perform tomographic imaging, the Y-direction scanning transmission structure 112 is used to drive the printing substrate 111 to move at a constant speed along the Y direction, thereby realizing CT scanning imaging.

[0029] Optionally, the print control system submodule includes a print control chassis and a print control display; The print control display is used to receive external commands to control the print control chassis; The printing control chassis is installed at the bottom of the printer frame and is used to control the power of the laser source, the movement of the powder spreading device, the movement of the X-direction printing transmission structure, the movement of the Y-direction printing transmission structure, the movement of the Z-direction printing transmission structure, and the movement of the Y-direction scanning transmission structure during the 3D printing process.

[0030] like Figure 2 and Figure 5 As shown, the printing control chassis 171 is mounted at the bottom of the printer frame 18 and is used for power control of the laser source, control of the powder spreading device, motion control of the X-axis printing transmission structure, motion control of the Y-axis printing transmission structure, motion control of the Z-axis printing transmission structure, and motion control of the Y-axis scanning transmission structure during metal 3D printing. Furthermore, it synchronously controls the X-ray detection module to achieve simultaneous detection and printing. Figure 2As shown, the printer frame 18 is used to fix the toner spreading device 13, specifically to fix the toner spreading box transmission structure, and also to fix the X-direction printing transmission structure 14, the Y-direction printing transmission structure 15, and the Z-direction printing transmission structure 16.

[0031] This invention addresses the problem of existing detection technologies failing to accurately identify defects generated during metal 3D printing, thus hindering the achievement of high-precision and dimensional detection of metal 3D printed objects. It provides rapid, efficient, and high-precision real-time detection of lattice defects and dimensional errors during metal 3D printing, thereby improving quality control and process performance. The invention also utilizes a vertical X-ray detection module directly above the printer body to emit X-rays perpendicular to the printing area, and a horizontal X-ray detection module to move the printing area at a constant speed along the Y-axis after each layer is printed. This enables X-ray tomography and reconstruction of the 3D model of the printed object. The reconstructed 3D model is then used to detect dimensional errors and lattice defects, solving the problem of existing detection technologies being unable to accurately identify defects generated during metal 3D printing and failing to meet the required detection accuracy and dimensional standards. This results in rapid, efficient, and high-precision real-time detection of lattice defects and dimensional errors during metal 3D printing, improving quality control and process performance.

[0032] Example 2 A 3D printing method based on cold cathode CT, performed using a 3D printing apparatus as described in any of the embodiments, includes: Initialize the 3D printing device; The system control module controls the laser source to 3D print the target object on the printing platform, and simultaneously controls the printing platform to move at a constant speed along the Y direction; The system control module controls the vertical and horizontal cold cathode tubes to emit X-rays onto the printing platform from the vertical and horizontal directions, respectively, and acquires the signals collected by the horizontal and vertical X-ray imaging detectors to reconstruct a three-dimensional model of the target object through X-ray tomography.

[0033] The system control module includes a main control server, a printing control system submodule, and an X-ray control system submodule. The main control server controls the printing control system submodule and the X-ray control system submodule through control signals. Printing control system software is installed on the printing control system submodule, and X-ray control system software is installed on the X-ray control system submodule.

[0034] The specific workflow is as follows: The first step is for the main control server 51 to initiate the initialization command, and to initialize the positions of the X-direction printing transmission structure 14, Y-direction printing transmission structure 15, Z-direction printing transmission structure 16, Y-direction scanning transmission structure 112, and powder spreading device 13 through the printing control system software 52.

[0035] In the second step, the printing control system software 52 controls the powder spreading device 13 to spread the first layer of metal powder on the printing substrate 111, and then returns to the initialization position.

[0036] In the third step, the printing control system software 52 controls the X-direction printing transmission structure 14 and the Y-direction printing transmission structure 15 to move the laser source 12 to the first printing point. Then, the printing control system submodule 17 starts the laser source 12 to begin printing and simultaneously controls the X-direction printing transmission structure 14 and the Y-direction printing transmission structure 15 to drive the laser source 12 to perform two-dimensional printing. After the printing is completed, it returns to the initialization position.

[0037] In the fourth step, the main control server 51 receives status signals from the vertical X-ray detection module 2 and the horizontal X-ray detection module 3 via the X-ray control system software 53. If both status signals read "Ready," a pulse synchronization signal is sent to the vertical X-ray detection module 2 and the horizontal X-ray detection module 3 to begin irradiation imaging. The main control server 51, through the printing control system software 52, synchronously controls the Y-direction scanning transmission structure 112 to drive the printing substrate 111 in a uniform Y-direction motion, achieving CT three-dimensional scanning detection. After the detection is complete, the Y-direction scanning transmission structure 112 is restored to its initial position. If the main control server 51 detects dimensional errors or lattice defects, the printing control system software 52 will reprint the layer. After reprinting, the main control server 51 re-performs a CT scan of the printed layer via the X-ray control system software 53. If the dimensional errors and lattice defects are not resolved, the subsequent 3D printing process is stopped, and the process jumps directly to the sixth step.

[0038] In the fifth step, the main control server 51 controls the printing transmission structure 16 in the Z direction through the printing control system software 52 to move the printing platform 11 down by one printing layer thickness, and repeats the process of the second, third and fourth steps.

[0039] Step 6: Metal 3D printing is complete. If the main control server 51 detects printing defects, the metal 3D printing process can be optimized by adjusting the power of the laser source 12 or the single-point printing time after analysis.

[0040] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A 3D printing device based on cold cathode CT, characterized in that, include: The printer body, vertical X-ray detection module, horizontal X-ray detection module, connecting frame, and system control module; The vertical X-ray detection module includes a vertical cold cathode tube and a vertical X-ray imaging detector; the vertical cold cathode tube is positioned directly above the printer body via the connecting frame and is used to emit vertical X-rays onto the printing platform; the vertical X-ray imaging detector is positioned below the printing platform and is used to collect vertical X-rays that penetrate the target object. The printing platform is located inside the printer body and is used to place the generated target object; The horizontal X-ray detection module includes a horizontal cold cathode tube and a horizontal X-ray imaging detector, which are embedded in the printer body. The horizontal X-ray imaging detector and the horizontal cold cathode tube are symmetrically arranged about the printing platform. The horizontal cold cathode tube is used to emit horizontal X-rays to the printing platform, and the horizontal X-ray imaging detector is used to collect horizontal X-rays that penetrate the target object. The system control module includes a main control server, a printing control system submodule, and an X-ray control system submodule. The printing control system submodule is used to control the laser source on the printer body to 3D print the target object on the printing platform, and at the same time control the printing platform to move at a constant speed along the Y direction. The X-ray control system submodule is used to control the vertical and horizontal cold cathode tubes to emit X-rays onto the printing platform. The main control server is used to acquire signals collected by the horizontal X-ray imaging detector and the vertical X-ray imaging detector to reconstruct a three-dimensional model of the target object through X-ray tomography; the main control server is also used to detect and analyze the size error and lattice defect of the 3D printed object in real time based on the reconstructed three-dimensional model, and control the printing control system submodule and the X-ray control system submodule through feedback. The vertical X-ray detection module also includes a vertical X-ray collimator and a vertical collimator fixing bracket; the vertical collimator fixing bracket is used to support and fix the vertical cold cathode tube and the vertical X-ray collimator; the conical beam generated by the vertical cold cathode tube is aligned with the center of the vertical X-ray collimator, and the vertical X-ray collimator is used to collimate the conical beam into a fan-shaped beam. The horizontal X-ray detection module also includes a horizontal X-ray collimator and a horizontal collimator fixing bracket; the horizontal collimator fixing bracket is used to support and fix the horizontal cold cathode tube and the horizontal X-ray collimator; the conical beam generated by the horizontal cold cathode tube is aligned with the center of the horizontal X-ray collimator, and the horizontal X-ray collimator is used to collimate the conical beam into a fan-shaped beam.

2. The 3D printing apparatus as described in claim 1, characterized in that, The printer body includes a printer frame, a printing platform, a laser source, a toner spreading device, and an X-direction printing transmission structure, a Y-direction printing transmission structure, and a Z-direction printing transmission structure disposed on the printer frame. The printing platform includes a printing substrate and a Y-direction scanning transmission structure; the powder spreading device is fixed on the printer frame and installed above the printing substrate, and is used to hold metal powder and spread and level it on the printing substrate; The X-direction printing transmission structure and the Y-direction printing transmission structure are used to drive the laser source to move and select areas on the printing substrate, and the Z-direction printing transmission structure is used to drive the printing substrate to move up and down in the Z direction. The Y-direction scanning transmission structure is used to drive the printing substrate to move at a constant speed along the Y direction.

3. The 3D printing apparatus as described in claim 2, characterized in that, The printing control system submodule includes a printing control chassis and a printing control display; The print control display is used to receive external commands to control the print control chassis; The printing control chassis is installed at the bottom of the printer frame and is used to control the power of the laser source, the movement of the powder spreading device, the movement of the X-direction printing transmission structure, the movement of the Y-direction printing transmission structure, the movement of the Z-direction printing transmission structure, and the movement of the Y-direction scanning transmission structure during the 3D printing process.

4. The 3D printing apparatus as described in claim 1, characterized in that, The printing control system submodule is used to adjust the power of the laser source or the single-point printing time.

5. A 3D printing method based on cold cathode CT, performed using a 3D printing apparatus as described in any one of claims 1-4, characterized in that, include: Initialize the 3D printing device; The system control module controls the laser source to 3D print the target object on the printing platform, and simultaneously controls the printing platform to move at a constant speed along the Y direction; The system control module controls the vertical and horizontal cold cathode tubes to emit X-rays onto the printing platform from the vertical and horizontal directions, respectively, and acquires the signals collected by the horizontal and vertical X-ray imaging detectors to reconstruct a three-dimensional model of the target object through X-ray tomography.

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