A method and device for real-time monitoring of resistivity and thermal conductivity in a photocuring 3D printing process

Abstract

This invention discloses a method and apparatus for real-time monitoring of resistivity and thermal conductivity during photopolymerization 3D printing. The main functions of this system are as follows: the measuring device controls the raising and lowering of the printing platform; simultaneously, an ultraviolet light source solidifies the liquid in a specific area at the bottom of the resin tank; after the ultraviolet light source is turned off, the measuring and control module controls the high-voltage power supply to be turned on; voltage is applied through the printing platform as the first electrode and the transparent ITO electrode at the bottom of the resin tank as the second electrode; simultaneously, the industrial control computer performs post-processing on the collected data, calculates the overall real-time resistivity of the sample, and inversely calculates the thermal conductivity of the sample. This invention solves the technical problem of existing technologies' inability to monitor the core functional indicators of high-voltage insulation components online.

Description

Technical Field

[0001] This invention relates to the field of real-time detection technology for 3D printed components, specifically to a method and apparatus for real-time monitoring of resistivity and thermal conductivity during photopolymerization 3D printing. Background Technology

[0002] Stereolithography (SLA), a widely used additive manufacturing technology, selectively cures liquid photosensitive resin layer by layer under ultraviolet light. This allows for the fabrication of components with complex structures, high surface finish, and excellent dimensional accuracy. These characteristics make SLA more suitable than other 3D printing technologies for manufacturing insulating components in high-voltage applications. Introducing SLA into the field of high-voltage insulation can realize the fabrication of irregularly shaped insulating components that are difficult to process using traditional methods, potentially providing new design freedom and manufacturing strategies for insulating components and equipment.

[0003] However, current SLA printing processes lack effective online monitoring methods for the insulation performance of the final product, making the printing process a "black box," relying solely on post-printing performance testing for verification. For high-voltage insulation components, volume resistivity is a key indicator determining whether the insulation material can maintain good insulation performance under high voltage, while thermal conductivity directly affects the component's heat dissipation capacity during operation; both jointly determine the long-term reliability of the insulation system. Traditional offline testing methods, which involve testing after printing, have a certain lag. If performance deficiencies are discovered only after printing, the entire printed part, or even the entire batch, may need to be scrapped, resulting in wasted time and materials. This makes product upgrades and subsequent process optimization difficult, often forcing R&D personnel to rely on extensive trial and error to explore process parameters, which is inefficient and costly. Summary of the Invention

[0004] The purpose of this invention is to address the technical problem that existing technologies cannot monitor the core functional indicators of high-voltage insulation components online, and to provide a method and device for real-time monitoring of resistivity and thermal conductivity during photopolymerization 3D printing.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for real-time monitoring of resistivity and thermal conductivity during photopolymerization 3D printing includes the following steps:

[0007] S1. Set the number of layers n when testing resistivity, where n is a positive integer;

[0008] S2. The printing device used for photopolymerization 3D printing is used as the first electrode, and the second and third electrodes are set at the bottom of the container containing liquid photosensitive resin.

[0009] S3. Load liquid photosensitive resin to ensure that it contacts the first electrode, the second electrode and the third electrode respectively, and form a three-electrode measurement circuit;

[0010] S4. Turn on the light curing light source to cure the liquid photosensitive resin. After curing is complete, turn off the light curing light source.

[0011] S5. Measure the thickness L of the cured sample. If the thickness L is the same as the preset thickness of the nth layer, apply a measurement voltage to the cured sample and measure the microcurrent.

[0012] S6. Stop the voltage output, record the microcurrent reading, calculate the overall volume resistivity of the solidified sample, and inversely derive the thermal conductivity.

[0013] The above steps allow for real-time monitoring of the volume resistivity and thermal conductivity of the printed component during SLA printing, improving testing efficiency. Based on the measured volume resistivity and thermal conductivity, it can be determined whether the physical characteristics of the cured component meet technical requirements. If the cured sample does not meet the requirements, adjustments can be made to the photocuring process by optimizing printing parameters, performing secondary photocuring, and optimizing the photosensitive resin formulation to ensure the printed sample is qualified.

[0014] Preferably, the process also includes step S7: if the thickness of the cured sample at this point is different from the preset thickness of the nth layer, printing continues until they are the same and then jumps to step S5. When the thickness of the cured sample does not reach the set thickness value, printing continues until the cured sample reaches the set measurement thickness, thereby ensuring the accuracy of the measurement.

[0015] Preferably, the process also includes step S8, where the printing device is raised after the calculation is completed, and the process jumps to step S4 to continue printing until all samples are printed. If the measured sample volume resistivity and thermal conductivity meet the requirements, printing continues; if they do not meet the requirements, printing continues after adjustments until a high-performance printed part is produced.

[0016] Preferably, the measuring voltage in S5 is a DC voltage, and the measuring voltage range is 10V~1000V. The magnitude of the measuring voltage can be adjusted according to the liquid photosensitive resin material used.

[0017] Preferably, a real-time monitoring device for resistivity and thermal conductivity during photopolymerization 3D printing is also provided for executing the aforementioned real-time monitoring method. The device includes a resin tank with a light-transmitting window at its bottom, an ITO electrode at the bottom of the resin tank, a printing platform within the resin tank, and a control device communicatively connected to the printing platform. The printing platform, ITO electrode, and control device are all electrically connected to a high-resistivity meter. The control device operates the printing platform wirelessly, and the high-resistivity meter applies voltage to the printing platform and ITO electrode and measures the current.

[0018] Preferably, the real-time monitoring device also includes an ultraviolet (UV) light source, which is positioned at a distance outside the resin tank, directly facing the light-transmitting window. The UV light source is communicatively connected to the control device. The UV light emitted by the UV light source passes through the light-transmitting window and acts on the liquid photosensitive resin, causing it to cure. The control device can wirelessly control the start and stop of the UV light source.

[0019] Preferably, the real-time monitoring device also includes an industrial control computer that is connected to the high resistance meter. The industrial control computer is an electronic calculator that can control and record the measurement values ​​of the high resistance meter and perform calculations on the values.

[0020] Preferably, the real-time monitoring device also includes a displacement sensor installed on the control device and connected to the industrial control computer. The displacement sensor is used to measure the thickness of the cured sample in real time so as to determine whether the preset number of printing layers has been reached.

[0021] Preferably, the ITO electrode has a thin sheet structure, with a central protected electrode at the center and an outer protected electrode at a distance from ground around the central protected electrode. The central protected electrode and the outer protected electrode are electrically connected to the high-resistivity meter, and the outer protected electrode is used to absorb small currents.

[0022] Preferably, the printing platform serves as the first electrode, used to apply a test voltage to the cured sample during interlayer measurement; the central protected electrode serves as the second electrode, forming a measurement circuit with the first electrode; and the peripheral protective electrode serves as the third electrode, maintaining the same potential as the second electrode during measurement to absorb surface leakage current. The printing platform, the central protected electrode, and the peripheral protective electrode together form a three-electrode measurement circuit.

[0023] Compared with existing technologies, the advantages of this invention are as follows: 1. A measurement circuit is formed by a first electrode set on the printing platform and a transparent ITO electrode set at the bottom of the resin tank. The ITO electrode adopts a protective electrode structure, which effectively eliminates the interference of the leakage current on the sample surface on the resistivity measurement of the material body, thereby realizing real-time detection of the insulation of the printed sample; 2. A control device is proposed to synchronize the opening and closing of the ultraviolet light source with the connection of the high resistance meter: at the preset test time, the light source is turned off and the high resistance meter is turned on for a single measurement. After the test is completed, the high resistance meter is disconnected and the light source is turned on again, and printing continues. This control method avoids interference with the photocuring reaction during the measurement process, while ensuring precise control of the test timing and improving detection efficiency; 3. The total resistance of the printed sample is obtained through multiple measurements. Combined with thickness normalization processing, the equivalent volume resistivity of the sample is obtained. On this basis, the thermal conductivity of the sample is derived by using the conductivity-thermal conductivity correlation formula established by offline calibration, thereby realizing rapid evaluation of the overall insulation and thermal conductivity of the printed part. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating a method for real-time monitoring of resistivity and thermal conductivity during photopolymerization 3D printing according to the present invention.

[0025] Figure 2 This is a schematic diagram of the structure of a real-time monitoring device for resistivity and thermal conductivity during photopolymerization 3D printing according to the present invention.

[0026] Figure 3 This is a planar schematic diagram of the ITO electrode of the present invention;

[0027] Figure 4 This is a line graph showing the current measurement results of an embodiment of the present invention.

[0028] In the diagram: 1. Printing platform; 2. ITO electrode; 21. External protective electrode; 22. Central protected electrode; 3. Ultraviolet light source; 4. High resistance meter; 5. Control device; 6. Industrial computer; 7. Resin tank; 8. Displacement sensor. Detailed Implementation

[0029] To enable those skilled in the art to clearly and completely understand the technical solution of the present invention, the present invention will be further described in detail below with reference to embodiments. Obviously, the embodiments described herein are only for explaining the present invention and are not intended to limit the scope of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0030] Example 1: As Figure 1 As shown, a method for real-time monitoring of resistivity and thermal conductivity during photopolymerization 3D printing includes the following steps:

[0031] S1. Set the number of layers n when testing resistivity, where n is a positive integer;

[0032] S2. The printing device used for photopolymerization 3D printing is used as the first electrode, and the second and third electrodes are set at the bottom of the container containing liquid photosensitive resin.

[0033] S3. Load liquid photosensitive resin to ensure that it contacts the first electrode, the second electrode and the third electrode respectively, and form a three-electrode measurement circuit;

[0034] S4. Turn on the light curing light source to cure the liquid photosensitive resin. After curing is complete, turn off the light curing light source.

[0035] S5. Measure the thickness L of the cured sample. If the thickness L is the same as the preset thickness of the nth layer, apply a measurement voltage to the cured sample and measure the microcurrent.

[0036] S6. Stop the voltage output, record the microcurrent reading, calculate the overall volume resistivity of the solidified sample, and inversely derive the thermal conductivity.

[0037] S7. If the thickness of the cured sample at this point is different from the preset thickness of the nth layer, continue printing until they are the same and then jump to S5.

[0038] S8. After the calculation is completed, operate the printing device to rise and jump to S4 to continue printing until all samples are printed.

[0039] Furthermore, the calculation formula in S6 is as follows:

[0040]

[0041]

[0042]

[0043] in, This represents the total resistance value of the currently cured resin. Apply voltage to the high-voltage power supply of the high-resistance meter. The current value is measured by a high-resistance, high-precision ammeter. The value represents the volume resistivity of the cured resin in real time, where A is the effective area of ​​the electrode and L is the thickness of the cured resin. The formula represents the thermal conductivity of the cured resin, where a, α, and b are empirical fitting constants. This formula may be adjusted depending on the material and filler, but the thermal conductivity can be obtained from the resistivity, thus providing online monitoring data for the preparation of customized performance materials. When the resistivity and thermal conductivity of the cured sample do not meet the expected values, optimization can be achieved through the following steps, including but not limited to: 1. Optimizing printing parameters: increasing exposure time, adjusting single-layer printing thickness, and increasing the resin temperature during printing to ensure resin fluidity and reduce the introduction of air gaps; 2. Secondary photocuring: performing additional UV curing treatment on the printed parts through secondary photocuring to improve the degree of curing; 3. Optimizing the photosensitive resin formulation: adjusting the proportion of photosensitive resin fillers, for example, increasing the proportion of fillers with higher resistivity.

[0044] Furthermore, the measuring voltage in S5 is a DC voltage, and the measuring voltage range is 10V~1000V.

[0045] The test voltage used is selected according to the resistance range to be measured. When the resistance of the target component is 1×10⁻⁶, 6 Ω~2×10 7 When the resistance is Ω, select a 10V test voltage. When the resistance of the target component is 1×10 15 Ω~2×10 16 Select a 1000V test voltage when the voltage is Ω.

[0046] Example 2: Figure 2 As shown, this application also provides a real-time monitoring device for resistivity and thermal conductivity during photopolymerization 3D printing, used to perform the above-mentioned real-time monitoring method. It includes a resin tank 7 with a light-transmitting window on the bottom, an ITO electrode 2 at the bottom of the resin tank 7, a printing platform 1 in the resin tank 7, a control device 5 connected to the printing platform 1, and the printing platform 1, the ITO electrode 2 and the control device 5 are all electrically connected to a high-resistivity meter 4.

[0047] In this embodiment, the printing platform 1 can be made of aluminum alloy or copper alloy. The resin tank 7 holds the liquid photosensitive resin used as the raw material for photocuring 3D printing. A light-transmitting window with dimensions of 286mm × 198mm is located at the center of its bottom. This window allows ultraviolet laser light to pass through the resin tank 7 and irradiate the liquid photosensitive resin. A release film made of PET (polyethylene terephthalate) is placed on the light-transmitting window. The release film is mechanically fixed to the bottom of the resin tank 7 by a frame and screws. An ITO electrode 2 is deposited on the release film using magnetron sputtering. The printing platform 1, which is communicatively connected to the control device 5, is positioned directly above the ITO electrode 2. The control device 5 can control the raising and lowering of the printing platform 1 via electrical signals to achieve the layered printing effect. The printing platform 1, ITO electrode 2, and control device 5 are all electrically connected to a high-resistivity meter 4. The control device 5 can also control the power supply of the high-resistivity meter 4, allowing it to apply a test voltage to the printing platform 1 and ITO electrode 2. In this embodiment, the ITO electrode 2 serves as a fixed measuring end, and the printing platform 1 serves as a movable measuring end. No additional sensors need to be inserted into the liquid resin, avoiding interference with the printing process. Simultaneously, it enables in-situ, non-destructive monitoring of the electrical and thermal properties of the resin material. This invention replaces traditional offline sampling and testing with continuous monitoring, overcoming the technical biases of offline sampling and testing, rapidly obtaining key parameters of the material's curing behavior, and accelerating the printing and testing process.

[0048] Furthermore, the real-time monitoring device also includes an ultraviolet light source 3, which is disposed at a distance outside the resin tank 7 and directly opposite the light-transmitting window. The ultraviolet light source 3 is communicatively connected to the control device 5.

[0049] An ultraviolet (UV) light source 3 is positioned outside the resin tank 7. The UV light source 3 emits UV light into the resin tank 7 to solidify the liquid resin. A light-transmitting window is positioned directly opposite the UV light source 3 on the resin tank 7, allowing the UV rays to act smoothly and precisely on the liquid resin, solidifying it into the shape of the target component. The control device 5 can also control the switching of the UV light source 3 via signals, causing it to perform the curing operation according to the preset parameters.

[0050] Furthermore, the real-time monitoring device also includes an industrial control computer 6 that is communicatively connected to the high-resistance meter 4.

[0051] Industrial computer 6 is an electronic computer used to record the current signal of the high-resistivity meter and calculate the resistivity of the current printed part and the current layer according to Ohm's law. At the same time, based on the effective dielectric theory framework, it uses empirical formulas to correlate thermal conductivity with resistivity, and then calculates the thermal conductivity.

[0052] Furthermore, the real-time monitoring device also includes a displacement sensor 8 installed on the control device 5 and connected to the industrial control computer 6.

[0053] In this embodiment, the displacement sensor 8 is most preferably a spectral confocal sensor; however, a laser triangulation sensor can also be used when high printing accuracy is not required. The displacement sensor 8 can measure the thickness of the cured sample in real time and transmit the measurement data wirelessly to the industrial control computer 6. The industrial control computer 6 compares the set printing thickness with the measured thickness and then issues instructions to continue printing or begin measurement.

[0054] Furthermore, such as Figure 3 As shown, the ITO electrode 2 has a thin sheet structure. A central protected electrode 22 is provided at the center of the ITO electrode 2. An outer protected electrode 21 is provided around the central protected electrode 22 at a distance from the ground. The central protected electrode 22 and the outer protected electrode 21 are electrically connected to the high resistance meter 4.

[0055] In this embodiment, the ITO electrode 2 has a thickness of 0.1 mm, the central protective electrode has a diameter of 5 cm, and the distance between the central protected electrode 22 and the outer protective electrode 21 is 1 mm.

[0056] Furthermore, the printing platform 1 serves as the first electrode, used to apply a test voltage to the cured sample during the interlayer measurement period; the central protected electrode 22 serves as the second electrode, forming a measurement circuit with the first electrode; and the peripheral protective electrode 21 serves as the third electrode, maintaining the same potential as the second electrode during the measurement process, used to absorb surface leakage current.

[0057] In this embodiment, the central protection electrode 22 is connected to the high-end input of the high-resistivity meter 4, and the outer protection electrode 21 is connected to the protection terminal. The high-resistivity meter 4 uses a voltage follower to ensure that the output voltage of the protection terminal is always equal to the high-end input. This ensures that the outer protection electrode 21 maintains the same potential as the central protected electrode 22 during measurement, with no current flowing between them. This confines the electric field in the central electrode region to a vertically downward one-dimensional uniform field, avoiding current leakage and measurement errors caused by edge electric field divergence in traditional two-electrode systems. The outer protection electrode 21 shields the leakage path caused by external stray electric fields and impurities adsorbed on the electrode surface, allowing the system to maintain a stable measurement baseline even after long-term continuous printing or multiple uses. The surface leakage current collected by the outer protection electrode 21 allows the high-resistivity meter 4 to measure only the current flowing through the central protected electrode 22. This is particularly suitable for detecting weak signals in incompletely cured or high-resistivity liquid photosensitive resins, making the resistivity data more accurately reflect the bulk resistance characteristics of the material.

[0058] Furthermore, based on the above-mentioned real-time monitoring method and device, the following experimental example is provided:

[0059] In this test example, the component to be printed is a high-voltage insulating support structure, and commercial photosensitive resin is used as the printing material. According to this application, a three-electrode system is used. The printing platform 1 itself is a metal component, serving as the unprotected electrode, and it is in direct contact with the upper surface of the sample. A transparent ITO electrode 2 is provided at the bottom of the resin tank 7. This ITO electrode 2 is treated by magnetron sputtering, with its central circular region serving as the central protected electrode 22 and its outer concentric ring region serving as the outer protective electrode 21. The insulation gap between the central protected electrode 22 and the outer protective electrode 21 is 1 mm. As an acceptance test, the volume resistivity is calculated using the current value after a fixed time, in accordance with relevant specifications.

[0060] For the printed part in this test case, a flat plate with dimensions of 100mm×100mm×2mm was used. A commercial 405nm UV curing 3D printer was used, with the exposure time set to 2.8s and the layer thickness set to d=50μm. A total of 40 layers were printed.

[0061] Because the volume resistivity of this photosensitive resin is as high as 10 after complete curing. 16Ω•cm, belonging to high insulating materials, requires a sufficiently large leakage current to ensure measurement accuracy. Therefore, according to this application, a test voltage of 1000V is selected. At the preset test time during printing, the control device 5 automatically performs the following operations: first, it pauses the lifting and lowering movement of the printing platform 1 and turns off the ultraviolet light source 3 to avoid interference from light on the current measurement; then, it connects the high-resistivity meter 4 and applies a 1000V DC test voltage to the ITO electrode 2 at the bottom of the resin tank 7. To stabilize the measurement value, the applied voltage is maintained for a certain period (adjusted according to the material, usually between 1 min and 30 min), and the leakage current I flowing through the cured sample is read. After reading, the control device 5 disconnects the high-resistivity meter 4 and resumes printing. The entire measurement process has minimal impact on the overall printing process. Through these multiple measurements, the equivalent volume resistivity of the sample at that moment is calculated. Combined with the offline calibrated conductivity-thermal conductivity correlation model, the thermal conductivity is inverted, thereby quickly evaluating whether the insulation and thermal conductivity performance of the printed part meets the design requirements.

[0062] In this case, n=20, meaning the resistivity is measured at layer 20 (more specifically, the layer thickness is 50μm × 20 = 1mm). At this point, the control device 5 shuts off the UV light source 3 and connects the high-resistivity meter 4. A voltage is applied to the cured sample via the printing platform 1, and the high-resistivity meter 4 measures the microcurrent passing through the cured sample. After applying the voltage for 30 minutes, the average current value from 1 minute to 3 minutes after 30 minutes is used to calculate the sample's volume resistivity for acceptance.

[0063] The current after 30 minutes is as follows Figure 4 As shown in the figure, we can obtain the average current I = 5.54 pA and U = 1000 V. Substituting these values ​​into the formula, we get:

[0064] =1.81×10 14 Ω

[0065] In this experimental example, the diameter of the central protective electrode 22 is d=5cm, and the gap between the outer protective electrode 21 and the central protective electrode 22 is g=1mm. Substituting into the formula, we can obtain:

[0066] =21.237cm 2

[0067] For a solidified sample, L=1mm, substituting into the formula yields:

[0068]

[0069] It can be seen that the volume resistivity of the solidified sample at this point is greater than 1×10⁻⁶. 16 Ω•cm, which meets the requirements for high-voltage insulation materials;

[0070] More specifically, the volume resistivity of the now-cured sample is substituted into the offline calibration model, where... The range is 1 to 2, and b is the intrinsic thermal conductivity of the material, ranging from 0.2 to 0.5. In this embodiment, a = 1.2 × 10⁻⁶. 32 , =2, b=0.15, therefore:

[0071]

[0072] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A method for real-time monitoring of resistivity and thermal conductivity during photopolymerization 3D printing, characterized in that, Includes the following steps: S1. Set the number of layers n when testing resistivity, where n is a positive integer; S2. The printing device used for photopolymerization 3D printing is used as the first electrode, and the second and third electrodes are set at the bottom of the container containing liquid photosensitive resin. S3. Load liquid photosensitive resin to ensure that it contacts the first electrode, the second electrode and the third electrode respectively, and form a three-electrode measurement circuit; S4. Turn on the light curing light source to cure the liquid photosensitive resin. After curing is complete, turn off the light curing light source. S5. Measure the thickness L of the cured sample. If the thickness L is the same as the preset thickness of the nth layer, apply a measurement voltage to the cured sample and measure the microcurrent. S6. Stop the voltage output, record the microcurrent reading, calculate the overall volume resistivity of the solidified sample, and inversely derive the thermal conductivity.

2. The method for real-time monitoring of resistivity and thermal conductivity during photopolymerization 3D printing according to claim 1, characterized in that, It also includes S7, if the thickness of the cured sample at this time is not the same as the preset thickness of the nth layer, then continue printing until they are the same and then jump to S5.

3. The method for real-time monitoring of resistivity and thermal conductivity during photopolymerization 3D printing according to claim 1, characterized in that, It also includes S8, after the calculation is completed, the printing device is raised and jumps to S4 to continue printing until all samples are printed.

4. The method for real-time monitoring of resistivity and thermal conductivity during photopolymerization 3D printing according to claim 1, characterized in that, The voltage measured in S5 is a DC voltage, and the voltage range is 10V~1000V.

5. A real-time monitoring device for resistivity and thermal conductivity during photopolymerization 3D printing, used to execute the real-time monitoring method according to any one of claims 1 to 4, characterized in that, The resin tank (7) with a light-transmitting window at the bottom is provided. An ITO electrode (2) is provided at the bottom of the resin tank (7). A printing platform (1) is provided in the resin tank (7). A control device (5) is connected to the printing platform (1). The printing platform (1), the ITO electrode (2) and the control device (5) are all electrically connected to a high-resistivity meter (4).

6. The real-time monitoring device for resistivity and thermal conductivity during photopolymerization 3D printing according to claim 5, characterized in that, It also includes an ultraviolet light source (3), which is disposed at a distance outside the resin tank (7) and directly opposite the light-transmitting window. The ultraviolet light source (3) is communicatively connected to the control device (5).

7. The real-time monitoring device for resistivity and thermal conductivity during photopolymerization 3D printing according to claim 5, characterized in that, It also includes an industrial control computer (6) that is communicatively connected to the high resistance meter (4).

8. The real-time monitoring device for resistivity and thermal conductivity during photopolymerization 3D printing according to claim 5, characterized in that, It also includes a displacement sensor (8) mounted on the control device (5) and connected in communication with the industrial computer (6).

9. The real-time monitoring device for resistivity and thermal conductivity during photopolymerization 3D printing according to claim 5, characterized in that, The ITO electrode (2) has a thin sheet structure. A central protected electrode (22) is provided in the center of the ITO electrode (2). An outer protected electrode (21) is provided around the central protected electrode (22) at a distance from the ground. The central protected electrode (22) and the outer protected electrode (21) are electrically connected to the high resistance meter (4).

10. The real-time monitoring device for resistivity and thermal conductivity during photopolymerization 3D printing according to claim 9, characterized in that, The printing platform (1) serves as the first electrode, used to apply a test voltage to the cured sample during the interlayer measurement period; the central protected electrode (22) serves as the second electrode, forming a measurement circuit with the first electrode; the peripheral protective electrode (21) serves as the third electrode, maintaining an equipotential state with the second electrode during the measurement process, and is used to absorb surface leakage current.

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