Testing method of 3D printing light-cured resin material

Abstract

The invention relates to the technical field of testing, in particular to a method for testing a 3D printing light-cured resin material, and the method comprises the following steps: obtaining a test model containing a specified geometric structure; wherein the test model is obtained by printing a plurality of slice layers with the same thickness layer by layer along the first direction based on single-layer single exposure and gradient increase exposure time rules; and measuring the curing thickness of each slice layer of the test model to obtain the curing thickness of the light-cured resin material at different exposure times. Compared with a mode of printing a test model through multiple exposure in the prior art, the test method of the 3D printing light-cured resin material has the advantages that the test model is printed in a single-slice-layer single-exposure mode, and the exposure times, the switching complexity of all slice layers and the problem of non-uniform curing caused by multiple exposure can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of testing technologies, and particularly to a testing method for 3D printing photocurable resin materials. Background Art

[0002] In view of the current situation of resin material testing in DLP and LCD process 3D printers in the 3D printing photocuring market, we have to face a series of challenges and deficiencies. Although these printers are widely popular due to their advantages in accuracy, speed, and cost-effectiveness, the technical differences among brands, including fluctuations in light source intensity, subtle differences in light source wavelength, resolution of the projection screen display, and unique device process designs, all have a significant impact on the final printing effect.

[0003] The current mainstream resin material testing method, that is, randomly selecting test points for blind printing according to the exposure time range recommended by the material supplier, although it can initially screen out resin materials suitable for a specific printer to a certain extent, its limitations are obvious. This method highly depends on the experience and intuitive judgment of the operator. At the macroscopic level, the test piece after cleaning is observed by the naked eye to evaluate the clarity of the surface text, dimensional accuracy, gap consistency, and the forming ability of the overhanging structure, etc. However, this subjective and rough evaluation method has the defects of a long test cycle and low test accuracy. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a testing method for 3D printing photocurable resin materials.

[0005] In a first aspect, an embodiment of the present invention provides a testing method for 3D printing photocurable resin materials, and the method includes:

[0006] Obtaining a test model including a specified geometric structure; wherein, the test model is obtained by layer-by-layer printing of multiple sliced layers with the same thickness based on the rule of single-layer single-exposure and gradient-increasing exposure time along a first direction;

[0007] Measuring the curing thickness of each sliced layer of the test model to obtain the curing thickness of the photocurable resin material at multiple exposure times;

[0008] Combining multiple exposure times, multiple curing thicknesses, and the average light source intensity of the printer, calculating the critical curing thickness and critical energy value of the photocurable resin material and determining the optimal exposure time;

[0009] Combining the critical curing thickness, critical energy value, and optimal exposure time to obtain the test result.

[0010] Combined with the first aspect, the step of obtaining a test model including a specified geometric structure includes:

[0011] Obtain a test model with a specified geometric structure;

[0012] Slice the test model with a preset layer thickness to obtain a plurality of slice layers arranged in sequence along a first direction;

[0013] Combine the recommended exposure time and the preset adjustment step to determine the test exposure time for each slice layer;

[0014] Combine all the test exposure times and gradually print each slice layer along the first direction to obtain a test model.

[0015] Combined with the first aspect, the steps of printing a test model including a specified geometric structure based on the single-layer single-exposure and gradient-increasing exposure time rule further include:

[0016] For each target measurement point on the 3D printer, obtain the light intensity of the light emitted by the printing light source detected at the target measurement point during the printing exposure process;

[0017] Calculate the average value of all the light intensities to obtain the average light source intensity of the 3D printer.

[0018] Combined with the first aspect, the steps of calculating the critical curing thickness and the critical energy value of the photocuring resin material by combining multiple exposure times, multiple curing thicknesses, and the average light source intensity of the printer include:

[0019] Obtain the sampling data of multiple sampling points on the slice layer; the sampling data includes the exposure time and the curing thickness;

[0020] Combine multiple sampling data to calculate the first fitting coefficient and the second fitting coefficient;

[0021] Combine the first fitting coefficient, the second fitting coefficient, the exposure time of the test model, and the average light source intensity to calculate the critical curing thickness and the critical energy value.

[0022] Combined with the first aspect, the steps of combining multiple sampling data to calculate the first fitting coefficient and the second fitting coefficient include:

[0023] Calculate according to the following formula:

[0024]

[0025] where a1 is the first fitting coefficient, b1 is the second fitting coefficient, is the average value of the exposure times of all sampling points, is the average value of the curing thicknesses of all sampling points, x i is the exposure time of the i-th sampling point, y i is the curing thickness of the i-th sampling point.

[0026] In combination with the first aspect, the steps of calculating the critical curing thickness and the critical energy value by combining the first fitting coefficient, the second fitting coefficient, the exposure time of the test model, and the average light source intensity include:

[0027] Calculate using the following formula:

[0028]

[0029] h c = a1 × ln(t × I avg ) + b1;

[0030] where E C is the critical energy value, h c is the critical curing thickness, t is the exposure time of the test model, and I avg is the average light source intensity.

[0031] In combination with the first aspect, after the step of obtaining the sampling data of multiple sampling points on the slice layer; the sampling data includes the sampling data of the exposure time and the curing thickness, further including:

[0032] Calculate the third fitting coefficient and the fourth fitting coefficient by combining multiple sampling data;

[0033] Calculate the predicted curing thickness by combining the third fitting coefficient, the fourth fitting coefficient, and the initial exposure time;

[0034] Judge whether the difference between the predicted curing thickness and the expected thickness is within the preset range;

[0035] If not, adjust the exposure time based on the preset adjustment step and the initial exposure time until the difference between the predicted curing thickness corresponding to the adjusted exposure time and the expected thickness is within the preset range;

[0036] Take the current exposure time as the optimal exposure time corresponding to the photocuring resin material.

[0037] In combination with the first aspect, the steps of calculating the third fitting coefficient and the fourth fitting coefficient by combining multiple sampling data include:

[0038] Calculate using the following formula:

[0039]

[0040] where a2 is the third fitting coefficient, b2 is the fourth fitting coefficient, x i is the exposure time of the i-th sampling point, and y i is the curing thickness of the i-th sampling point.

[0041] In combination with the first aspect, the steps of calculating the predicted curing thickness by combining the third fitting coefficient, the fourth fitting coefficient, and the initial exposure time include:

[0042] Calculate using the following formula:

[0043] h y = a2 × ln t x + b2;

[0044] where h y is the predicted curing thickness, t x is the exposure time corresponding to the predicted curing thickness, a2 is the third fitting coefficient, and b2 is the fourth fitting coefficient.

[0045] In combination with the first aspect, after the steps of measuring the curing thickness of each slice layer of the test model to obtain the curing thickness of the photocuring resin material at multiple exposure times, it further includes:

[0046] Calculate the coefficient of determination of the linear regression model by combining multiple sampling data;

[0047] Determine whether the coefficient of determination is greater than a preset threshold;

[0048] If so, use the exposure time corresponding to the predicted curing thickness of the test model as the target exposure time of the target entity model.

[0049] The embodiments of the present invention bring the following beneficial effects: The test method for 3D printing photocuring resin materials provided in this application includes: obtaining a test model containing a specified geometric structure; wherein, the test model is obtained by layer-by-layer printing of multiple slice layers with the same thickness along the first direction based on the rule of single-layer single-exposure and gradient-increasing exposure time; measuring the curing thickness of each slice layer of the test model to obtain the curing thickness of the photocuring resin material at multiple exposure times; combining multiple exposure times, multiple curing thicknesses, and the average light source intensity of the printer to calculate the critical curing thickness and critical energy value of the photocuring resin material and determine the optimal exposure time; combining the critical curing thickness, critical energy value, and optimal exposure time to obtain the test result.

[0050] The test method for the 3D printing photocuring resin material provided by this application is based on the rule of single exposure for each slice layer and gradually increasing the exposure time along the first direction to print multiple slice layers to obtain a test model. Then, the curing thickness is measured for the test model under different exposure times, and further data processing is performed on the measured data to accurately calculate each test index and obtain the test result. Compared with the method of printing the test model by multiple exposures in the prior art, this application uses the method of single exposure for a single slice layer to print the test model, which can reduce the number of exposures, the complexity of switching between slice layers, and the problem of uneven curing caused by multiple exposures, thereby improving the stability of the printing process, facilitating the improvement of the accuracy of the test result, and further facilitating the optimization of the 3D printing effect and the improvement of the 3D printing efficiency.

[0051] Other features and advantages of the present invention will be described in the following specification, and part of them will be obvious from the specification or understood by implementing the present invention. The objectives and other advantages of the present invention are achieved and obtained by the structures specifically pointed out in the specification, claims, and drawings.

[0052] To make the above objectives, features, and advantages of the present invention more obvious and understandable, the following specifically enumerates preferred embodiments and, in conjunction with the accompanying drawings, makes the following detailed description. Brief Description of the Drawings

[0053] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0054] Figure 1 It is a schematic flowchart of the test method for the 3D printing photocuring resin material provided by the embodiment of the present invention;

[0055] Figure 2 It is a top view schematic diagram of the test model in the test method for the 3D printing photocuring resin material provided by the embodiment of the present invention;

[0056] Figure 3 It is a side view schematic diagram of the test model obtained by 3D printing using the single-layer multiple-exposure method in the prior art;

[0057] Figure 4 It is a side view schematic diagram of the test model obtained by 3D printing using the single-layer single-exposure technology in the test method for the 3D printing photocuring numerical material provided by the embodiment of the present invention;

[0058] Figure 5Schematic diagram of the structure of the electronic device provided by the embodiment of the present invention.

[0059] Reference numerals:

[0060] 130 - Processor, 131 - Memory, 132 - Bus, 133 - Communication interface. Detailed implementation manners

[0061] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0062] To facilitate the understanding of this embodiment, the technical terms designed in this application will be briefly introduced below.

[0063] DLP (Digital Light Processing) is a display technology based on digital micromirror device (DMD). It forms an image by reflecting light from a light source onto tens of thousands of tiny mirrors, with each mirror corresponding to a pixel. These mirrors can quickly switch states and reflect light at different angles to control the brightness and color of each pixel.

[0064] LCD (Liquid Crystal Display) is a technology that adjusts the transmission or reflection of light by controlling the electric field of liquid crystal materials to display images. It is widely used in various devices such as televisions, computer monitors, smartphones, and tablet computers.

[0065] After introducing the technical terms involved in this application, next, the application scenarios and design concepts of the embodiments of this application will be briefly introduced.

[0066] The existing testing methods mainly randomly select test points for blind printing within the exposure time range recommended by material suppliers, and then rely on the experience and intuitive judgment of operators to evaluate and obtain test results. This method has the following technical defects:

[0067] Long testing cycle: Since it is necessary to try different exposure times multiple times, coupled with the cleaning and drying processes after each printing, the overall testing cycle is greatly extended, reducing the efficiency of R & D and production;

[0068] Low test accuracy: It is difficult to capture micron-level detail differences with the naked eye. Especially for components with high-precision requirements, the accuracy of this method cannot meet strict quality control standards.

[0069] High printing failure rate: The randomly selected exposure time after adopting the above detection method is not suitable for all resin materials, resulting in frequent printing failures, which not only wastes materials and time but also increases the test cost.

[0070] In summary, the testing method for 3D printing photocurable resin materials urgently needs to be innovated to overcome the limitations of existing methods and promote the further development and application of 3D printing technology.

[0071] Based on this, the embodiments of this application provide a testing method for 3D printing photocurable resin materials.

[0072] Embodiment 1

[0073] This application provides a testing method for 3D printing photocurable resin materials. As shown in combination with Figure 1 the method includes:

[0074] S110, obtaining a test model containing a specified geometric structure; wherein, the test model is obtained by layer-by-layer printing of multiple slice layers with the same thickness based on the rule of single-layer single exposure and gradually increasing exposure time in the first direction.

[0075] S120, measuring the curing thickness of each slice layer of the test model to obtain the curing thickness of the photocurable resin material at multiple exposure times.

[0076] S130, combining multiple exposure times, multiple curing thicknesses, and the average light source intensity of the 3D printer to calculate the critical curing thickness and critical energy value of the photocurable resin material and determine the optimal exposure time;

[0077] S140, combining the critical curing thickness, critical energy value, and optimal exposure time to obtain the test result.

[0078] In this application, a test model containing specified structural features is printed based on a single-slice layer single exposure and an exposure time rule with a gradient increase in the first direction extending along the slice layer. Then, the cured thickness measurement is performed to obtain the cured thickness of the photocuring resin material at different exposure times. Data processing is carried out based on the multiple cured thicknesses corresponding to multiple times and the homogeneous light source intensity of the light emitted by the 3D printer to calculate the critical cured thickness and the critical energy value, and determine the optimal exposure time, thereby obtaining the test results of the photocuring resin material. In this application, the test model is printed by single-layer single exposure with a gradient increase in exposure time, replacing the single-layer multiple exposure printing method in the prior art. This can simplify the printing process, reduce the complexity of the single-layer multiple exposure process and the problem of uneven curing, improve the stability of the printing process, and facilitate the accurate calculation of various test indicators required for the measurement results after the cured thickness measurement, thereby simplifying the test process and improving the test accuracy.

[0079] Combined with the first aspect, step S110 includes:

[0080] S111, obtain a test model with a specified geometric structure.

[0081] S112, slice the test model with a preset layer thickness to obtain a plurality of slice layers arranged in sequence along the first direction.

[0082] S113, combine the recommended exposure time and the preset adjustment step size to determine the test exposure time of each slice layer.

[0083] S114, combine all the test exposure times and gradually perform single exposure printing on each slice layer along the first direction to obtain the test model.

[0084] It can be understood that the test model in step S111 can be a model drawn by a tester on 3D software, or can be obtained by retrieving data through a preset connection port from a removable storage device pre-stored, or can be downloaded from a file based on a local area network, Internet of Things, etc. This is only an example here and is not limited. Among them, the test model should have a specified geometric structure convenient for testing various indicators of the photocuring resin material. For example, the structural top view of the test model selected in this application is as Figure 2 shown, including 7 slice layers numbered 1-7 along the first direction ( Figure 2 in is the left-to-right direction).

[0085] After the test model is opened in a 3D printer or a device communicatively connected to a 3D printer, slicing is performed based on slicing software in the prior art (such as Slimplify 3D, PrusaSlicer, etc.) to convert the three-dimensional test model into a series of two-dimensional slice layers, each layer representing a step in the printing process, and the arrangement order of the two-dimensional slice layers is the first direction in the printing process. In this embodiment, the thickness of each two-dimensional slice layer is the same.

[0086] After that, a test exposure time is assigned to each slice layer. In this application, according to the recommended curing time provided by the material supplier of the photocurable resin material, the first test exposure time t1 of the first slice layer is determined; then, for the second to the Nth slice layers, a preset adjustment step (Δt) is gradually increased on the basis of the first test exposure time, that is, the Nth test exposure time t n of the Nth slice layer = t1 + Δt. In this way, it is beneficial to evaluate the influence of different exposure times on the curing effect.

[0087] As an example, in this application, there are 7 slice layers in total, t1 = 2s, and Δt = 0.5s. The test exposure times of these 7 slice layers are: 2s, 2.5s, 3s, 3.5s, 4s, 4.5s, 5s.

[0088] Combined with Figure 3 As shown, in the prior art, a multi-exposure technique is adopted for the 3D image to be printed to achieve resin material curing. The basic principle of this technique is that during the photocuring forming process of 3D printing, the exposure time of each slice layer is set to a fixed value. As the printing process progresses, the system will perform multi-exposure operations layer by layer according to the preset layer thickness parameters. The side view of the obtained test model is as shown in Figure 3 As shown, it can be seen that as the printing process progresses, the layer thickness of each slice layer arranged in the first direction gradually increases (see the increase in the dimension in the second direction). It can be understood that in the multi-exposure technique, since it is necessary to perform multi-exposure on the same layer, it is difficult to avoid the problem of uneven curing, which often leads to defects such as ripples and unevenness on the model surface, and the switching between slice layers and multi-exposure during the printing process may bring uncertain factors, resulting in a relatively high printing failure rate and an unsatisfactory finished product rate.

[0089] And in this application, combined with Figure 4As shown, the thickness of each slice layer (i.e., the layer thickness of the slice layer) is a preset fixed value. However, different from traditional multiple exposures, it does not increase the curing thickness by exposing the same position multiple times, but realizes different curing thicknesses of the resin material with different exposure times by single-layer single exposure and gradually increasing the exposure time along the first direction arranged by the slice layer. Compared with multiple exposures, the single-layer single exposure technology simplifies the printing process and improves the printing efficiency by completing the curing of each layer at one time, reducing the number of exposures and the complexity of layer-to-layer switching. Moreover, by precisely controlling the increase of the exposure time, the gradual curing of the photocurable resin material in different regions is achieved, effectively avoiding the problem of uneven curing caused by multiple exposures, not only improving the surface finish of the model, but also ensuring the stability and consistency of each layer structure, thus significantly improving the printing accuracy of the test model.

[0090] Combined with the first aspect, before step S110, it further includes:

[0091] S100, for each target measurement point on the 3D printer, obtain the light intensity of the light emitted by the printing light source detected at the target measurement point during the printing exposure process.

[0092] S100, calculate the average value of all the light intensities to obtain the average light source intensity of the 3D printer.

[0093] Under the condition of not installing the forming platform, first conduct the test of the light source intensity of the 3D printer. This test step is directly related to the accuracy of the subsequent test process. To ensure the test accuracy, before the test in this application, first carefully place the light intensity test tooling into the resin tank of the 3D printer to ensure that the light intensity test tooling is in close contact with the target measurement point, avoiding any interference from external factors. During the printing exposure process of the printer, sequentially place the high-sensitivity light intensity sensor into the target measurement points to accurately capture and measure the light intensity emitted from the printer light source. The selection of these points is based on the actual layout of the printing area and the light source distribution characteristics, aiming to comprehensively and accurately evaluate the light source intensity distribution of the 3D printer. Record the test data (light intensity) of each point.

[0094] After that, the tester collects all the test data and calculates the average value I of all the points avg , this average value is an important indicator to measure the stability and uniformity of the printer light source intensity. It can help us understand the current working state of the printer and provide a strong basis for subsequent test decisions. Subsequently, take this average value as the average light source intensity.

[0095] It is understandable that after obtaining the average value of the light source intensity, during subsequent use, the light intensity of the light generated by the 3D printer can be measured again and compared with the average value of the light source intensity to determine whether the light source intensity of the 3D printer is within the optimal range. Also, the light intensities between different points can be compared to promptly detect potential unevenness or attenuation of the light source intensity, thereby further improving the accuracy of the test.

[0096] After printing the test model in step S110, to ensure the safety of the operation and the integrity of the model, it is first necessary to wear disposable protective gloves to effectively isolate the potential chemical risks posed by the uncured resin material and keep the operation environment clean. Subsequently, the operator needs to carefully remove the three groups of test models that have been printed and cured inside from the resin tank. During the removal process, the movements should be steady and continuous to avoid causing any unnecessary physical damage or deformation to the test models.

[0097] After removing the test models, the cleaning process immediately follows. This step aims to thoroughly remove any uncured resin material remaining on the model surface to ensure the accuracy of the test results and the appearance quality of the model. For this purpose, anhydrous ethanol is selected as the main cleaning agent in this application. Its good solubility and volatility can effectively decompose and carry away the uncured resin residue. At the same time, a soft and lint-free dust-free cloth is used for wiping. This kind of cloth can not only provide uniform wiping force but also prevent secondary contamination of the test model surface caused by cloth fiber residues.

[0098] During the wiping process, special attention should be paid to cleaning the detailed parts of the model to ensure that every part is thoroughly treated. In addition, to avoid uneven wiping caused by rapid evaporation of alcohol, it is recommended to slightly moisten the dust-free cloth before wiping, but not too wet to prevent excess alcohol from adhering to the model surface. Repeat the above cleaning steps until the surface of the test model is completely clean and smooth, meeting the test requirements.

[0099] After that, in step S120, a high-precision micrometer is used to accurately measure the light-curing thickness.

[0100] Specifically, before use, zero calibration should be performed according to the instructions provided by the supplier to eliminate the instrument's own errors. This usually involves gently touching the probe against a standard block of known thickness, adjusting the reading to the standard value, and ensuring that the measurement starting point is accurate. After that, place the probe of the micrometer caliper steadily and perpendicularly to the surface of the test model, avoiding applying excessive pressure that may cause deformation. Among them, the number of test models in step S110 can be multiple, and the specified structures of each test model may be the same or different. Measure at the center points of each end face of each test model and record the cured thickness values of each point. Ensure that there are at least independent readings for the measurement data of each test model at the same exposure time to improve the reliability of the data. Subsequently, record in detail the cured thickness data of the test model at different exposure times, including the model number, exposure time, measurement position, and corresponding thickness values. Preferably, use a spreadsheet or professional software to organize the data for subsequent analysis.

[0101] In combination with the first aspect, in step S130, calculate the critical cured thickness and critical energy value of the photocuring resin material by combining multiple exposure times, multiple cured thicknesses, and the average light source intensity of the printer, specifically including:

[0102] S131, obtain the sampling data of multiple sampling points on the sliced layer; the sampling data includes the exposure time and the cured thickness.

[0103] For each sampling point, the sampling data after cured thickness measurement should include the exposure time and the cured thickness of the sliced layer where the sampling point is located.

[0104] S132, calculate the first fitting coefficient and the second fitting coefficient by combining multiple sampling data.

[0105] S133, calculate the critical cured thickness and critical energy value by combining the first fitting coefficient, the second fitting coefficient, the exposure time of the test model, and the average light source intensity.

[0106] In combination with the first aspect, step S132 includes:

[0107] Calculate according to the following formula:

[0108]

[0109] where a1 is the first fitting coefficient, b1 is the second fitting coefficient, is the average value of the exposure times of all sampling points, is the average value of the cured thicknesses of all sampling points, x i is the exposure time of the i-th sampling point, y i is the cured thickness of the i-th sampling point.

[0110] According to the basic principles of physics, the energy value generated by light illumination is equal to the product of the average light source intensity and the exposure time, i.e.:

[0111] E = t×I avg ; where E is the energy value generated by light illumination, I avg is the average light source intensity, and t is the exposure time of the test model.

[0112] However, in practical applications, the energy value is often expressed in logarithmic form. After performing a logarithmic transformation on the above formula, the natural logarithm lnE of the energy value generated by light illumination is associated with the measured curing thickness h, and a critical energy value E C is found. When the natural logarithm of the energy value is less than lnE C , the curing thickness will be lower than a certain acceptable minimum value h min .

[0113] Taking the acceptable minimum value h min as the critical curing thickness h c of this test, i.e.:

[0114] h c = h min .

[0115] Combined with the first aspect, step S133 includes:

[0116] Calculating with the following formula:

[0117]

[0118] h c = a1×ln(t×I avg ) + b1;

[0119] where E C is the critical energy value, h c is the critical curing thickness, t is the exposure time of the test model, and I avg is the average light source intensity.

[0120] It can be understood that, given a1, b1, t, and I avg , the critical curing thickness h c is calculated, and further the critical energy value E C is calculated.

[0121] Combined with the first aspect, after step S131, it further includes:

[0122] S131a, calculating the third fitting coefficient and the fourth fitting coefficient by combining multiple sampling data.

[0123] S131b, calculate the predicted curing thickness by combining the third fitting coefficient, the fourth fitting coefficient, and the initial exposure time.

[0124] S131c, determine whether the difference between the predicted curing thickness and the expected thickness is within a preset range.

[0125] If not, execute steps S131d - S131f; if so, execute step S131f.

[0126] S131d, adjust the exposure time based on the preset adjustment step and the initial exposure time until the difference between the predicted curing thickness corresponding to the adjusted exposure time and the expected thickness is within the preset range.

[0127] S131f, take the current exposure time as the optimal exposure time corresponding to the photocuring resin material.

[0128] The relationship between the exposure time of the light source to the resin material and the curing depth exhibits a unique logarithmically linear slow - growth characteristic. Among them, when the light source projects onto the surface of the liquid resin material, the photosensitive components in the resin absorb light energy and undergo a chemical reaction, thereby achieving the transformation from liquid to solid, and this process is called curing. In the initial stage of exposure, the curing thickness increases relatively fast with the increase of exposure time; but as time goes by, the growth rate gradually slows down until it reaches a critical value, at which time the curing depth hardly increases with the increase of exposure time. Therefore, it is necessary to determine the minimum exposure time (i.e., the optimal exposure time in this application) that meets the curing requirements to improve production efficiency.

[0129] In the actual application process, a value greater than the thickness of the slice layer is usually used as the predicted curing thickness h y , and then the speculated exposure time t is deduced backward based on the above formula x . The specific reason is that when the curing thickness is greater than the layer thickness, each layer of material has more opportunities to fully fuse with the previous layer during the curing process, forming a stronger intermolecular bonding force. This enhanced inter - layer adhesion can effectively reduce the delamination or cracking phenomena that may occur during the printing process and the post - processing stage. In addition, a thicker cured layer can provide a more uniform curing effect, reducing the surface roughness or weakening areas caused by insufficient curing. This not only improves the appearance quality of the printed part but also enhances its structural integrity.

[0130] In this application, the preset range in S131d is set to 0.04 - 0.08 mm, preferably set to 0.05 - 0.07 mm. The initial exposure time can be a time randomly input by the tester, or can be an initial value stored in advance. After calculating the predicted curing thickness based on this initial exposure time, calculate the difference between the predicted curing thickness and the expected thickness (the curing thickness determined according to actual needs), and determine whether it is within the preset range. If it is within the preset range, the optimal exposure time can be directly determined; if it is not within the preset range, adjust the initial exposure time to obtain a new predicted curing thickness that meets the above requirements, and the corresponding optimal exposure time.

[0131] Combined with the first aspect, step S131a includes:

[0132] Calculate according to the following formula:

[0133]

[0134] where a2 is the third fitting coefficient, b2 is the fourth fitting coefficient, x i is the exposure time of the i-th sampling point, and y i is the curing thickness of the i-th sampling point.

[0135] Combined with the first aspect, step S131b includes:

[0136] Calculate according to the following formula:

[0137] h y = a2 × ln t x + b2;

[0138] where h y is the predicted curing thickness, t x is the exposure time corresponding to the predicted curing thickness, a2 is the third fitting coefficient, and b2 is the fourth fitting coefficient.

[0139] After calculating the third fitting coefficient a2 and the fourth fitting coefficient b2, the predicted curing thickness h y will change according to the predicted exposure time t x Through the formula h y = a2 × ln t x + b2, the h x corresponding to different t y can be calculated.

[0140] As an example, if the expected thickness is 0.04 mm and the preset range is selected to be 0.05 - 0.07 mm, at this time, it can be determined that the value range of the predicted curing thickness should be 0.09 - 0.11. At this time, randomly input an initial exposure time t x1 , and the corresponding h y1= 0.08 mm. At this time, the predicted curing thickness does not meet the preset requirements. At this time, based on the preset adjustment step, such as Δt x = 0.1 s, adjust the initial exposure time t x1 to obtain a new exposure time t x2 = t x1 + Δt x . At this time, the newly calculated h y2 = 0.095 mm meets the preset requirements. Then the optimal exposure time obtained is t x2 .

[0141] Combined with the first aspect, after step S120, it further includes:

[0142] S150, calculate the coefficient of determination of the linear regression model by combining multiple sampling data;

[0143] S160, determine whether the coefficient of determination is greater than the preset threshold;

[0144] If so, execute step S170.

[0145] S170, use the exposure time corresponding to the predicted curing thickness of the test model as the target exposure time of the target entity model.

[0146] In this embodiment, based on the multiple exposure times measured in step S120 and their corresponding curing thicknesses, a fitting value is calculated, usually using the following formula:

[0147]

[0148] where R 2 is the coefficient of determination, y i is the actual observed value, is the model predicted value, is the average of the actual observations.

[0149] R 2 plays a crucial role in statistics. It is the core index for evaluating the fitting degree of the regression model to the observed data. This index intuitively shows the explanatory ability of the model to the observed data, that is, the percentage of the variation of the dependent variable (thickness h) that can be explained by the independent variable (time t in this example). The value range of R 2 is between 0 - 1. That is, through R 2 , the size of the error in the test of the exposure time (t) and the curing thickness (h) can be indirectly evaluated. When the R 2 value approaches 1, the explanatory ability of the independent variable (exposure time t) to the dependent variable (curing thickness h) is extremely strong. At this time, the accuracy of the test results calculated by steps S130 - S140 based on the measurement data of this test model meets the test requirements. On the contrary, if R2 If the value is close to 0, it indicates that the model's ability to interpret the data is very limited, and the independent variable can hardly explain the variation of the dependent variable. In this case, the accuracy of the test results calculated by performing steps S130 - S140 is difficult to meet the test requirements. Therefore, by comparing R 2 with a preset threshold, it can be determined whether the fitting requirement is met. In this application, the preset threshold is 0.95, and this threshold can be adjusted according to the actual measurement accuracy requirements. This is only an example here and is not limited.

[0150] When the value of R 2 ≤ 0.95, this usually means that the test error is relatively large. In this case, the relationship between the exposure time (t) and the curing thickness (h) may not be fully captured by the model, resulting in limited predictive ability of the model. This relatively large test error may further affect the accuracy of the exposure time (tx) and the printing layer thickness (hy). Therefore, it is recommended to re - measure the data of the exposure time (t) and the curing thickness (h), or re - print the test model and then measure. By re - collecting the data, we can more accurately understand the true relationship between the exposure time (t) and the curing thickness (h), thereby improving the fitting degree and predictive ability of the model until the value of R 2 calculated again is greater than the preset threshold of 0.95. At this time, the exposure time corresponding to the predicted curing thickness of the test model printed this time is used as the target exposure time of the target entity model.

[0151] When the value of R 2 > 0.95, it indicates that the test error is relatively small. In this case, the test model meets the test requirements, and based on the data of the target curing thickness and the target exposure time measured on this test model, steps S130 - S140 can be performed to accurately calculate the target optimal exposure time (tx) and the curing thickness (hy) of the target slice layer.

[0152] Combined with the first aspect, after step S140, it further includes:

[0153] S200, obtain the target model.

[0154] S210, perform slicing processing on the target model to obtain multiple target slice layers.

[0155] S220, based on the optimal exposure time, control the 3D printer to sequentially expose and print multiple target slice layers to obtain the target entity model.

[0156] It can be understood that after the test based on steps S110 - S140 obtains a test result that meets the test accuracy requirements, the optimal exposure time in the test result is used as the working parameter for actual 3D printing to control the 3D printer to print the target model, so as to obtain a target entity model that meets the requirements. Among them, the target model includes the specified geometric structure of the target entity model.

[0157] In a second aspect, an embodiment of the present application provides an electronic device. In combination with Figure 5 As shown, the electronic device includes a memory 131 and a processor 130. The memory 131 is used to store a computer program, and the processor 130 runs the computer program to enable the electronic device to execute the above method.

[0158] Further, in combination with Figure 5 As shown, the electronic device further includes a bus 132 and a communication interface 133. The processor 130, the communication interface 133, and the memory 131 are connected through the bus 132.

[0159] Among them, the memory 131 may include a high-speed random access memory (RAM, Random Access Memory), and may also include a non-volatile memory, such as at least one disk memory. Through at least one communication interface 133 (which can be wired or wireless), a communication connection is established between this system network element and at least one other network element. The Internet, wide area network, local area network, metropolitan area network, etc. can be used. The bus 132 can be an ISA bus, a PCI bus, an EISA bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of representation, Figure 5 only a single bidirectional arrow is used in

[0160] The processor 130 may be an integrated circuit chip with the ability to process signals. In the implementation process, each step of the above method may be completed by the integrated logic circuit of the hardware in the processor 130 or the instructions in the form of software. The above-mentioned processor 130 may be a general-purpose processor, including a central processing unit (CPU for short), a network processor (NP for short), etc.; it may also be a digital signal processor (DSP for short), an application specific integrated circuit (ASIC for short), a field-programmable gate array (FPGA for short), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present invention. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the method disclosed in combination with the embodiments of the present invention may be directly embodied as being executed and completed by the hardware decoding processor, or executed and completed by a combination of the hardware and software modules in the decoding processor. The software module may be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. This storage medium is located in the memory 131, and the processor 130 reads the information in the memory 131 and combines its hardware to complete the steps of the method in the foregoing embodiments.

[0161] In a fourth aspect, an embodiment of the present application provides a readable storage medium. When a computer program instruction stored in the readable storage medium is read and run by a processor, the above method is executed.

[0162] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems and devices described above may refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0163] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0164] If the above-described functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs.

[0165] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0166] Finally, it should be noted that the above embodiments are only specific embodiments of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting them. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art within the technical scope disclosed by the present invention can still modify the technical solutions described in the foregoing embodiments, or can easily think of changes, or make equivalent replacements for some of the technical features; and these modifications, changes, or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A testing method for 3D printing light-curing resin materials, characterized in that: The method comprises: Acquire a test model including a specified geometric structure; wherein the test model is obtained by printing a plurality of slice layers having the same thickness layer by layer based on a single-layer single exposure and a gradient increase exposure time rule along a first direction; Measuring the cured thickness of each slice layer of the test model to obtain the cured thickness of the photocurable resin material at multiple exposure times; Calculate the critical curing thickness and critical energy value of the photocurable resin material and determine the optimal exposure time by combining multiple exposure times, multiple curing thicknesses, and an average light source intensity of the 3D printer; The test result is obtained by combining the critical curing thickness, the critical energy value, the optimal exposure time and the optimal exposure time.

2. The method according to claim 1, characterized in that The steps to obtain a test model containing the specified geometry include: Get a test model with a specified geometry; Slicing the test model with a preset layer thickness to obtain a plurality of slice layers arranged in sequence along a first direction; Determine the test exposure time of each slice layer in combination with the recommended exposure time and the preset adjustment step size; Combined with all the test exposure times, single exposure printing is performed step by step along the first direction on each slice layer to obtain the test model.

3. The method according to claim 1, characterized in that The step of printing a test model including a specified geometric structure based on a single-layer single-exposure and gradient-increase exposure time rule also includes: For each target measurement point on the 3D printer, obtain the light intensity of the light emitted by the printing light source detected at the target measurement point during the printing exposure process; The average value of all light intensities is calculated to obtain the mean light source intensity of the 3D printer.

4. The method according to claim 2, characterized in that: The step of calculating the critical curing thickness and critical energy value of the photocurable resin material by combining multiple exposure times, multiple curing thicknesses, and an average light source intensity of the printer comprises: Acquire sampling data of a plurality of sampling points on the slice layer; the sampling data includes exposure time and curing thickness; Calculating a first fitting coefficient and a second fitting coefficient by combining a plurality of sampling data; The critical curing thickness and the critical energy value are calculated by combining the first fitting coefficient, the second fitting coefficient, the exposure time of the test model, and the average light source intensity.

5. The method according to claim 4, characterized in that The step of calculating the first fitting coefficient and the second fitting coefficient by combining a plurality of sampling data comprises: Calculate using the following formula: Among them, a1 is the first fitting coefficient, b1 is the second fitting coefficient, is the mean exposure time of all sampling points, is the average value of the solidification thickness of all sampling points, x i is the exposure time of the i-th sampling point, y i is the solidification thickness of the i-th sampling point.

6. The method according to claim 5, characterized in that The step of calculating the critical curing thickness and the critical energy value by combining the first fitting coefficient, the second fitting coefficient, the exposure time of the test model, and the average light source intensity includes: Calculate with the following formula: h c =a1×ln(t×I avg )+b1; Among them, E C is the critical energy value, h c is the critical curing thickness, t is the exposure time of the test model, I avg is the mean light source intensity.

7. The method according to claim 4, characterized in that After the step of acquiring sampling data of a plurality of sampling points on the slice layer; wherein the sampling data includes sampling data of exposure time and solidification thickness, the method further includes: Calculating a third fitting coefficient and a fourth fitting coefficient by combining a plurality of sampling data; Calculate the predicted cured thickness by combining the third fitting coefficient, the fourth fitting coefficient, and the initial exposure time; Determining whether the difference between the predicted cured thickness and the expected thickness is within a preset range; If not, adjusting the exposure time based on the preset adjustment step and the initial exposure time until the difference between the predicted cured thickness corresponding to the adjusted exposure time and the expected thickness is within the preset range; The current exposure time is used as the optimal exposure time corresponding to the photocurable resin material.

8. The method according to claim 7, characterized in that The step of calculating the third fitting coefficient and the fourth fitting coefficient by combining the plurality of sampling data comprises: Calculate with the following formula: Wherein, a2 is the third fitting coefficient, b2 is the fourth fitting coefficient, and x i is the exposure time of the i-th sampling point, y i is the solidification thickness of the i-th sampling point.

9. The method according to claim 8, characterized in that The step of calculating and predicting the cured thickness by combining the third fitting coefficient, the fourth fitting coefficient, and the initial exposure time comprises: Calculate with the following formula: h y =a2×lnt x +b2; Among them, h y To predict the cured thickness, t x is the exposure time corresponding to the predicted cured thickness, a2 is the third fitting coefficient, and b2 is the fourth fitting coefficient.

10. The method according to claim 1, characterized in that After measuring the cured thickness of each slice layer of the test model to obtain the cured thickness of the photocurable resin material under multiple exposure times, the method further includes: Combine multiple sample data to calculate the coefficient of determination of the linear regression model; Determining whether the determination coefficient is greater than a preset threshold; If so, the exposure time corresponding to the predicted solidified thickness of the test model is used as the target exposure time of the target solid model.

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