Rapid detection method for fiber end breakage rate

Abstract

The invention relates to the technical field of fiber performance test and evaluation, in particular to a method for rapidly measuring the fiber breakage rate of a fiber bundle by combining a computer and amplification equipment. The invention provides a rapid detection method of a fiber end breakage rate. The detection method comprises the following steps: S1, preparing a sample; s2, obtaining a fiber cross section; s3, automatically identifying the image; and S4, calculating the fiber end breakage rate. According to the method, a laser confocal microscope is adopted to amplify the fiber cross section and continuously photograph the fiber cross section for multiple times, computer image analysis software is adopted to automatically identify and integrate the obtained whole bundle of fiber cross sections, overlapping areas among photos are removed, and the complete and accurate fiber cross section is obtained. Metallographic software is adopted to identify and mark the cellosilk, so that the rapid and accurate measurement of the cellosilk is realized.

Description

Technical Field

[0001] The invention relates to the technical field of fiber performance testing and evaluation, in particular to a method for quickly determining the breakage rate of fiber bundles by combining a computer with an amplifying device. Background Art

[0002] Fibers are not only used to make textiles but, more importantly, they serve as reinforcements for composites with resins, metals, ceramics, and carbon, creating advanced composite materials. These are widely used in aerospace, transportation, sports and leisure, wind power generation, and other fields. The breakage rate is a key indicator of fiber performance, significantly affecting fiber strength and the strength and structural properties of the resulting composites. Therefore, rapid and accurate measurement of the breakage rate is crucial for industrial production.

[0003] The fiber diameter is small (generally around 10 μm) and the number of fibers in a single bundle is large (3,000, 12,000, 24,000, etc.). Therefore, when measuring the fiber breakage rate using traditional manual methods, a portion of the fiber strands is usually selected, which is not only time-consuming and labor-intensive, but also often cannot accurately represent the level of the entire fiber bundle. Especially for longer fiber strands, since the fiber strands are prone to bending and deformation, or folding, this can cause large errors in the measurement results. On the other hand, when manually counting the fiber strands, due to their small diameter and large number, counting errors are very likely to occur during the manual counting process, resulting in manual measurement errors. Moreover, without a recorder to record these manual measurement errors, it is impossible to trace the manual measurement errors, resulting in poor credibility of the results.

[0004] Therefore, providing a method for quickly and accurately detecting the fiber breakage rate is of great significance for fiber performance characterization, process improvement and quality control. Summary of the Invention

[0005] Based on the above analysis, the present invention discloses a rapid detection method for fiber breakage rate, which is used to solve at least one of the following problems: traditional manual measurement involves selecting part of the fiber strands, which is not only time-consuming and labor-intensive, but also often cannot accurately represent the level of the entire bundle of fibers; for longer fiber strands, the fiber strands are prone to bending and deformation, or folding, which brings large errors to the measurement results; and due to the small diameter and large number of fibers, manual measurement errors are easily generated, and the credibility of the results is poor when there is no recorder to record them.

[0006] In one aspect, the present invention discloses a method for quickly detecting fiber breakage rate, the method comprising the following steps:

[0007] S1: Sample preparation, including resin impregnation and curing of the treated fiber bundles, cutting and mounting, as well as wet grinding and polishing:

[0008] S2: Obtaining the fiber cross section, including: magnifying the cross section of the fiber bundle until each fiber strand is clearly visible, taking multiple photos continuously until all fiber strand cross sections of the entire fiber bundle are obtained;

[0009] S3: Automatic image recognition; including: automatic recognition and integration of multiple photos taken in S2 to obtain complete and accurate fiber cross-sectional images;

[0010] Step 3.2: Based on the color difference between the fiber and the resin, all the fiber filaments are marked by adjusting the threshold value, and the number of fiber filaments is counted;

[0011] By using the above method, the fiber breakage rate of the fiber bundle can be detected quickly and accurately.

[0012] S4: Determine the fiber breakage rate based on the specified number of fiber filaments in the fiber bundle in S1 and the statistical number of fiber filaments obtained in S3.

[0013] In S1, the processing includes axially straightening the fiber bundle, fixing the root of the fiber bundle, and combing the fiber bundle from top to bottom along the root of the fiber bundle; wherein an adhesive is used to spot-glue and fix the root of the fiber bundle to place the fiber bundle vertically.

[0014] The fiber bundles treated in S1 are sequentially subjected to resin impregnation and curing, cutting and inlaying, and wet grinding and polishing, specifically including:

[0015] Step 1.2, infiltrating with uncured resin; curing with gradient curing;

[0016] Step 1.3, cutting the fiber bundle into 5-15 mm specimens, and cold mounting the cut specimens;

[0017] Step 1.4: First, wet-grind the embedded sample on a grinding machine from coarse to fine under running water, and then polish it on a polishing machine.

[0018] In step 1.2, the uncured resin includes epoxy resin and unsaturated polyester resin, preferably epoxy resin; the first stage of the gradient curing is: placing at 15-25°C for 30-90 minutes; the second stage is: transferring to an oven and curing at 30-70°C for 1-3 hours.

[0019] In the step 1.3, the cold mounting is performed using metallographic mounting materials.

[0020] In the step 1.4, the polishing materials are nylon polishing fabric and diamond polishing paste.

[0021] After the multiple photos taken in S2 are automatically identified and integrated, the following steps are performed: excluding overlapping areas between the photos.

[0022] In S2, all fiber filament cross sections of the entire fiber bundle are obtained by adjusting the moving step length; the moving step length is 450 to 480 μm.

[0023] In step 3.2, the fiber filaments are marked using metallographic software, and the threshold range is set to 150-250.

[0024] In said S4, the calculation formula of fiber breakage rate is S=(mn) / m*100%;

[0025] Here, m is the specified number of fiber filaments in the fiber bundle in S1, n is the number of fiber filaments counted by the counter obtained in S3, and mn is the number of broken fiber filaments.

[0026] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0027] 1. The present invention establishes a rapid detection method for fiber breakage rate. First, a laser confocal microscope is used to magnify the fiber cross section, and the magnified fiber bundle cross section is photographed multiple times to ensure that an image of the entire fiber bundle cross section is obtained. Subsequently, computer image analysis software is used to automatically identify and integrate the obtained cross section of the entire fiber bundle, and the overlapping areas between the photos are eliminated to obtain a complete and accurate fiber cross section. Finally, metallographic software is used to utilize the color difference between the fiber and the resin and adjust the threshold to identify and mark the fiber filaments. After all the fiber filaments are identified and marked, a counter is used to count the number of fiber filaments, thereby achieving rapid and accurate measurement of the fiber filaments.

[0028] 2. During sample preparation, the present invention achieves mutual dispersion of the fibers by impregnating the fiber bundle sample with epoxy resin and then performing a step-by-step curing process, thereby avoiding measurement errors caused by fiber bending and folding. Metallographic mounting of the cured fiber bundle sample prevents fiber breakage or fragmentation during subsequent polishing. The polishing process utilizes nylon polishing fabric and diamond polishing paste, resulting in a clearly defined fiber cross-section with no scratches.

[0029] 3. In the process of obtaining the fiber cross section, the microscope magnification was set to 500 times, the moving step was set to 450-480 μm, and photos were taken continuously multiple times so that there was a certain overlap between the photos to ensure that the image of the cross section of the entire bundle of fiber filaments was obtained.

[0030] 4. During the fiber marking process, the threshold method is used, and the threshold range is set to 150-250, so that all fiber boundaries are correctly identified and the accuracy of fiber counting is guaranteed.

[0031] 5. In the present invention, after the fiber bundle cross section is magnified and photographed multiple times to obtain an image of the entire fiber bundle cross section, computer image analysis software is used to identify and integrate the entire fiber bundle cross section, and overlapping areas are eliminated to obtain a complete and accurate cross section of the entire fiber bundle; finally, metallographic software is used for the identification and marking process of the fiber filaments, and a counter is used for the counting process of the fiber filaments. Therefore, the entire process is recorded accordingly, and the entire process is verifiable and traceable, ensuring the credibility of the measurement results.

[0032] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of the present invention will be described in the following description, and some advantages will become apparent from the description or be learned through practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are only used for the purpose of illustrating specific embodiments and are not to be considered as limiting the present invention. Throughout the drawings, the same reference symbols denote the same components.

[0034] Figure 1 This is a schematic diagram of the fiber breakage rate measurement process;

[0035] Figure 2 This is a metallographic photograph of the fiber cross section. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0037] To address the time-consuming, labor-intensive, inefficient, and difficult-to-accurately measure issues of traditional fiber breakage rate measurement methods, the present invention provides a rapid fiber breakage rate detection method that enables rapid and accurate measurement of fiber breakage rate. The fibers include carbon fibers and glass fibers with diameters less than 5 μm. When the diameter is less than 5 μm, it is difficult to distinguish individual fiber strands due to the small diameter, making direct photography or other non-magnification observation methods impossible to measure.

[0038] The measuring method provided by the present invention comprises the following steps:

[0039] S1: Sample preparation; including:

[0040] Step 1.1, straighten the fiber bundle axially, fix the root of the fiber bundle, and comb along the root of the fiber bundle from top to bottom;

[0041] Step 1.2, impregnating and curing the fiber bundle treated in step 1.1 with resin;

[0042] Step 1.3, cutting and inlaying the fiber bundles processed in step 1.2;

[0043] Step 1.4, wet grinding and polishing the fiber bundle treated in step 1.3;

[0044] S2: Obtaining fiber cross-sections; including:

[0045] Step 2.1: Enlarge the cross section of the fiber bundle until each fiber strand is clearly visible;

[0046] Step 2.2, taking multiple photos to obtain all fiber cross-sections of the entire fiber bundle;

[0047] S3: Automatic image recognition; including:

[0048] Step 3.1, using computer image analysis software to automatically identify and integrate all the obtained fiber cross-section photos, and remove the overlapping areas between the photos;

[0049] Step 3.2: Mark all fiber filaments and count the number of fiber filaments;

[0050] S4: Determine the fiber breakage rate based on the specified number of fiber filaments in the fiber bundle in S1 and the statistical number of fiber filaments obtained in S3.

[0051] By adopting the above-mentioned measurement method, a rapid and accurate measurement of the entire fiber bundle can be achieved.

[0052] S1: During the sample preparation process, the selected fiber bundles are first fixed and combed to avoid measurement errors caused by bending and folding of the fiber bundles; the combed fiber bundles are then fully infiltrated with epoxy resin to ensure that the fiber filaments are completely separated and to avoid mutual interference between the fiber filaments; then, a step-by-step curing method is adopted to gel the resin; finally, the prepared test sample is obtained through metallographic mounting, wet grinding and polishing.

[0053] Specifically, in step 1.1, first, a fiber bundle sample with a length of 30 mm is taken and axially straightened, and adhesive is used to fix it along the root of the fiber bundle. The adhesive is preferably 502 glue.

[0054] Place the fiber bundle vertically and comb it from top to bottom along the root of the fiber bundle to ensure the vertical arrangement of the fibers and avoid measurement errors caused by fiber bending or folding; a comb is preferably used for combing during the combing process.

[0055] In the step 1.2, the test sample is infiltrated with an uncured resin, such as epoxy resin or unsaturated polyester resin, preferably epoxy resin. Epoxy resin has low viscosity and high fluidity, ensuring that all fiber filaments are infiltrated and completely separated (especially for carbon fiber / glass fiber with a diameter of <5 μm), ensuring that the fiber filaments are dispersed and vertical, and avoiding interference between the fiber filaments causing measurement errors. The infiltration time is 10-20 minutes, such as 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, 20 minutes, preferably 15 minutes. The advantage of sufficient infiltration is that since the fiber itself is brittle, direct polishing will cause the fiber to break easily, resulting in measurement errors. By fully infiltrating the fiber filaments with resin, each fiber filament is wrapped with resin, and the supporting effect of the resin makes the fiber filaments less likely to break during the polishing process.

[0056] In the step 1.2, the curing process adopts a gradient curing method, and the gradient curing includes two curing stages: the first stage and the second stage. The first stage of the gradient curing: the resin is placed at room temperature (15-25°C) for 30-90 minutes to make the resin initially gel and avoid displacement or bending of the fiber during the transfer process. The room temperature can be 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, preferably 23°C; the placement time under room temperature is 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, preferably 60 minutes.

[0057] The second stage of gradient curing involves transferring the resin to an oven and curing it at 30-70°C for 1-3 hours to ensure complete crosslinking of the resin and prevent loose folding of the fibers. The oven temperature can be 30°C, 40°C, 50°C, 60°C, or 70°C, preferably 50°C; the curing time can be 1 hour, 1.5 hours, 2 hours, 2.5 hours, or 3 hours, preferably 2 hours.

[0058] In step 1.3, the fiber bundle prepared in step 1.2 is cut into 5-15 mm specimens, such as 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, and 15 mm, using a cutting machine equipped with a diamond grinding wheel. Water cooling is applied during the cutting process to ensure that the test cross-section is free of delamination or cracking.

[0059] The cut specimens are cold-mounted. Preferably, metallographic mounting materials are used for mounting and embedding and solidification. On the one hand, metallographic mounting can ensure that the fiber monofilaments are in an absolutely vertical dispersion state to avoid fiber tilting or falling off during subsequent polishing. On the other hand, the high-hardness resin of metallographic mounting can withstand diamond polishing to ensure that the fiber cross section is not damaged.

[0060] Furthermore, a small specimen clamp is used to hold the specimen during mounting to ensure that the cross section of the specimen is not skewed.

[0061] In step 1.4, the embedded sample is first wet-ground on a grinding machine from coarse to fine under running water, and then polished on a polishing machine using nylon polishing fabric and diamond polishing paste. The cross section of the polished sample is clearly visible under a microscope without obvious fine linear scratches.

[0062] Specifically, the present invention employs wet grinding from coarse to fine under flowing water. On the one hand, the continuous cooling of the flowing water prevents localized high temperatures from softening the resin or thermally deforming the fibers, ensuring vertical dispersion of the fibers and the accuracy of subsequent fiber diameter measurements. On the other hand, the flowing water washes away abrasive debris and loose particles, preventing deeper scratches caused by abrasive clogging and providing a smooth base for subsequent polishing. This graded wet grinding from coarse to fine not only ensures the rapid removal of inlay excess under coarse grinding conditions, forming a smooth reference surface, but also, combined with fine grinding, gradually eliminates coarse grinding scratches, laying the foundation for subsequent polishing.

[0063] Furthermore, the nylon fabric used in the present invention is soft and elastically conforms to the fiber cross-section, protecting the fiber structure and preventing fiber tearing or shedding caused by hard polishing materials. Diamond polishing paste, on the other hand, rapidly cuts through epoxy resin, ensuring a smooth polished fiber-resin interface. Therefore, the present invention utilizes nylon fabric and diamond polishing paste for polishing, thereby protecting the fiber structure and ensuring polishing efficiency.

[0064] The S2: obtaining the fiber bundle cross section specifically includes:

[0065] Step 2.1: Enlarge the cross section of the fiber bundle; Step 2.2: Take a photo.

[0066] In step 2.1, during the fiber bundle cross-section magnification process, the present invention first places the polished sample on the sample stage of a laser confocal microscope. During placement, the bottom of the sample is filled with plasticine to make the sample cross-section horizontal, ensuring measurement accuracy. In the present invention, the magnification of the microscope is gradually increased from 50x. At a magnification of 500x, each fiber strand is clearly visible, and a magnification of 500x is ultimately selected.

[0067] After the fiber bundle is magnified, due to the large magnification, the boundary of the entire fiber bundle exceeds the observation range, and one photo cannot cover the entire cross-section of the entire fiber bundle. Therefore, a laser confocal microscope is used to take continuous photos to ensure that all angles of the fiber cross-section are captured.

[0068] In the process of taking the picture in step 2.2, the moving step length is adjusted to accurately obtain all the fiber cross sections of the entire bundle of fibers, ensuring that no fiber is missed and no fiber is obtained repeatedly during the shooting process, thereby ensuring the accuracy of the fiber counting.

[0069] Specifically, the length of the shooting area of each photo in the present invention is 500μm. In order to ensure that the fiber filaments are not missed during the shooting process, the present invention selects a moving step length of less than 500μm, so that there is a certain amount of overlap between different photos. The smaller the moving step length, the greater the overlap between different photos, and the more it can ensure that all fiber filaments are fully photographed to avoid omissions. However, when the moving step length is too small and the overlap amount is too large, the computer has to process too many repeated areas, which also causes large errors. Therefore, in the present invention, the moving step length is set to 450-480μm, such as 450μm, 460μm, 470μm, 480μm, preferably 480μm, which can ensure that there is overlap between photos to avoid omissions, and can minimize the errors caused by the computer processing too many overlapping areas.

[0070] Furthermore, when taking photos, the moving direction of the photo is: along the horizontal direction from left to right, continuously move the sample stage until the boundary of the fiber cross section, then turn to the vertical direction from top to bottom and move one step, then along the horizontal direction from right to left, continuously move the sample stage until the boundary of the fiber cross section, then turn to the vertical direction from top to bottom and move one step, and repeat this cycle to obtain an image of the cross section of the entire bundle of fiber filaments.

[0071] Furthermore, during the shooting process, the shooting starts from the upper left edge of the fiber filament cross section, and a fiber filament at the rightmost edge of the image is selected as the marking point. The fiber filament is slowly moved one step in the horizontal direction from left to right, and a photo is taken, and so on, until the right edge position; then the vertical direction from top to bottom is turned to move one step, and a photo is taken, and then the horizontal direction from right to left is slowly moved one step, and a photo is taken, and so on, until the left edge position; then the vertical direction from top to bottom is turned to move one step, and a photo is taken; and this cycle is repeated to obtain an image of the cross section of the entire bundle of fiber filaments.

[0072] Furthermore, an editing program may be used to enable the sample stage to move automatically and take pictures continuously.

[0073] like Figure 2As shown, in the partial cross-section taken, each fiber is clearly visible, and there is no mutual interference or overlap between the fibers.

[0074] The S3: automatic image recognition specifically includes:

[0075] Step 3.1, photo integration;

[0076] Step 3.2: Fiber labeling.

[0077] In the step 3.1, during the photo integration process, all the fiber bundle cross-section photos taken in S2 are imported into the computer, and the image analysis software OLYCIA m3 is used to automatically identify and integrate the obtained photos of the entire fiber bundle cross-section, and the overlapping areas between the photos are eliminated to obtain a complete and accurate fiber cross-section.

[0078] In step 3.2, during the fiber marking process, since the fibers and resin have different colors, the grayscale is set to clearly distinguish the color difference between the fibers and the resin. The threshold is adjusted to account for different types of fibers and differences in observer vision and angle. The threshold range is 150-250, such as 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, and preferably 200.

[0079] Specifically, the metallographic software is opened, fibers are added as a new phase, and marked in red. The center of a fiber's diameter is selected. During the marking process, the threshold is adjusted until all fibers are colored red by the computer. If the red color exceeds the fiber's diameter, the threshold is lowered until all fibers appear red. After the fibers are marked, individual areas with inappropriate coloring can be manually modified to ensure that all fibers are correctly identified. After all fibers are identified and marked, a counter is used to count the number of fibers.

[0080] S4: Calculation of broken ends rate

[0081] The fiber breakage rate is calculated according to the breakage rate calculation formula S=(mn) / m*100%.

[0082] Here, m is the specified number of fiber filaments in the fiber bundle in S1, n is the number of fiber filaments counted by the counter obtained in S3, and mn is the number of broken fiber filaments.

[0083] For the same batch of fiber bundles, the fiber breakage rates of Examples 1-5 measured using the method of the present invention were 5.43%-5.75%, which were -4.24%-1.57% compared with the fiber breakage rate (5.66%) measured by manual counting in Control Example 1, and the deviations were all within 5%.

[0084] The fiber bundles used in the following examples and comparative examples are KD-A silicon carbide fibers produced by the National University of Defense Technology, and the fiber diameter is 7 μm.

[0085] Example 1

[0086] S1: Sample preparation

[0087] A fiber bundle sample with a length of 30 mm was axially straightened and sequentially subjected to processes such as glue curing and manual combing, resin infiltration, gradient curing, metallographic mounting, wet grinding, and polishing to obtain the sample to be tested. The detailed steps are as follows:

[0088] Step 1.1, Glue Curing and Manual Combing: First, axially straighten a 30 mm long fiber bundle specimen. Apply adhesive along the base of the fiber bundle. Place the fiber bundle vertically and comb the fiber bundle from top to bottom with a comb to ensure vertical fiber alignment and avoid measurement errors caused by fiber bending or folding.

[0089] Step 1.2, Resin Infiltration: After the fibers have been cured and manually combed in Step 1.1, infiltrate them with epoxy resin for 15 minutes. Epoxy resin has low viscosity and high fluidity, ensuring complete separation of the fiber filaments and avoiding measurement errors caused by uneven infiltration.

[0090] Step 1.3, gradient curing: The fiber bundle after impregnation is cured by gradient curing. The first stage is to place it at room temperature (23°C) for 60 minutes to allow the resin to initially gel and avoid displacement or bending of the fiber during the transfer process.

[0091] The second stage: the fiber that has been cured in the first stage is transferred to an oven and cured at 50°C for another 2 hours to ensure that the resin is fully cross-linked and avoid shrinkage and deformation.

[0092] Step 1.4, metallographic mounting: After resin infiltration and curing, the fiber bundle specimen is cut into 10 mm specimens using a cutting machine equipped with a diamond grinding wheel. The cutting is cooled with water to ensure that there is no delamination or cracking on the test section.

[0093] The cut specimens are inlaid with metallographic inlay materials, embedded and solidified. Metallographic inlay can ensure that the fiber monofilaments are in an absolutely vertical dispersion state, avoiding fiber tilting or falling off during subsequent polishing. The high-hardness resin of metallographic inlay can withstand diamond polishing to ensure that the fiber cross section is not damaged.

[0094] During the mounting process, a small specimen clamp is used to hold the specimen to ensure that the specimen cross section is not skewed.

[0095] Step 1.5, wet grinding and polishing: The embedded sample is first wet-ground on a grinding machine from coarse to fine under running water, and then polished on a polishing machine using nylon polishing fabric and diamond polishing paste. The cross-section of the polished sample is clearly visible under a microscope, with no obvious fine line scratches.

[0096] S2: Obtaining fiber cross-section

[0097] The process of obtaining the fiber cross section includes: magnifying the fiber cross section and taking photos.

[0098] Step 2.1, Magnify the Fiber Cross-Section: First, place the polished sample on the sample stage of the laser confocal microscope. During placement, fill the bottom of the sample with plasticine to make the sample cross-section horizontal to ensure measurement accuracy. Select a microscope magnification of 500x.

[0099] Step 2.2, Photo Capture: The horizontal direction from left to right is defined as the +X direction, the vertical direction from top to bottom is defined as the Y direction, and the horizontal direction from right to left is defined as the -X direction. When photographing, start at the upper left edge of the fiber cross section, select a fiber at the rightmost edge of the image as a marker, slowly move one step in the +X direction and take a photo, and so on, until the right edge is located; then turn to the Y direction and move one step and take a photo, then slowly move one step in the -X direction and take a photo, and so on, until the left edge is located; then turn to the Y direction and move one step and take a photo; and repeat this cycle to obtain an image of the entire fiber cross section.

[0100] During the shooting process, the moving step length was set to 480 μm, and the editing program was used to automatically move the sample stage and continuously take pictures until all the fiber filaments were photographed.

[0101] S3: Automatic image recognition

[0102] The automatic image recognition process includes photo integration and fiber marking.

[0103] Step 3.1, photo integration: Import the fiber cross-section photos taken in S2 into the computer, and use the image analysis software OLYCIA m3 to integrate the photos of the entire fiber cross-section, remove the overlapping areas between the photos, and obtain a complete and accurate fiber cross-section.

[0104] Step 3.2, Fiber Marking: Open the metallographic software, select Add Fiber as a New Phase, and mark it red. Select the center of a fiber diameter. During the marking process, adjust the threshold to 200 until all fibers are marked red by the computer. After all fibers are identified and marked, use a counter to count the number of fibers. The calculator calculates the number of fibers to be 1185K.

[0105] S4: Calculation of fiber breakage rate

[0106] The number of fiber filaments in the fiber bundle used in the present invention is 12,000. The calculator counts the number of fiber filaments to be 11,317. According to the breakage rate calculation formula S=(mn) / m*100%, the fiber breakage rate is calculated to be (12,000-11,317) / 12,000*100%=5.69%.

[0107] m: the specified number of fiber filaments in the fiber bundle, n: the number of fiber filaments counted by a counter, and mn: the number of broken fiber filaments.

[0108] Example 2

[0109] S1: Sample preparation

[0110] A fiber bundle sample with a length of 30 mm was axially straightened and sequentially subjected to processes such as glue curing and manual combing, resin infiltration, gradient curing, metallographic mounting, wet grinding, and polishing to obtain the sample to be tested. The detailed steps are as follows:

[0111] Step 1.1, Glue Curing and Manual Combing: First, axially straighten a 30 mm long fiber bundle specimen. Apply adhesive along the base of the fiber bundle. Place the fiber bundle vertically and comb the fiber bundle from top to bottom with a comb to ensure vertical fiber alignment and avoid measurement errors caused by fiber bending or folding.

[0112] Step 1.2, Resin Infiltration: After the fibers have been cured and manually combed in Step 1.1, infiltrate them with epoxy resin for 10 minutes. Epoxy resin has low viscosity and high fluidity, ensuring complete separation of the fiber filaments and avoiding measurement errors caused by uneven infiltration.

[0113] Step 1.3, gradient curing: The impregnated fiber bundle is cured by gradient curing. The first stage is to place it at room temperature (15°C) for 90 minutes to allow the resin to initially gel and avoid displacement or bending of the fiber during the transfer process.

[0114] The second stage: the fiber cured in the first stage is transferred to an oven and cured at 30°C for another 3 hours to ensure that the resin is fully cross-linked and to avoid shrinkage and deformation.

[0115] Step 1.4, metallographic mounting: After resin infiltration and curing, the fiber bundle specimen is cut into 5 mm specimens using a cutting machine equipped with a diamond grinding wheel. The cutting is cooled with water to ensure that there is no delamination or cracking on the test section.

[0116] The cut specimens are inlaid with metallographic inlay materials, embedded and solidified. Metallographic inlay can ensure that the fiber monofilaments are in an absolutely vertical dispersion state, avoiding fiber tilting or falling off during subsequent polishing. The high-hardness resin of metallographic inlay can withstand diamond polishing to ensure that the fiber cross section is not damaged.

[0117] During the mounting process, a small specimen clamp is used to hold the specimen to ensure that the specimen cross section is not skewed.

[0118] Step 1.5, wet grinding and polishing: The embedded sample is first wet-ground on a grinding machine from coarse to fine under running water, and then polished on a polishing machine using nylon polishing fabric and diamond polishing paste. The cross-section of the polished sample is clearly visible under a microscope, with no obvious fine line scratches.

[0119] S2: Obtaining fiber cross-section

[0120] The process of obtaining the fiber cross section includes: magnifying the fiber cross section and taking photos.

[0121] Step 2.1, Magnify the Fiber Cross-Section: First, place the polished sample on the sample stage of the laser confocal microscope. During placement, fill the bottom of the sample with plasticine to make the sample cross-section horizontal to ensure measurement accuracy. Select a microscope magnification of 500x.

[0122] Step 2.2, Photo Capture: The horizontal direction from left to right is defined as the +X direction, the vertical direction from top to bottom is defined as the Y direction, and the horizontal direction from right to left is defined as the -X direction. When photographing, start at the upper left edge of the fiber cross section, select a fiber at the rightmost edge of the image as a marker, slowly move one step in the +X direction and take a photo, and so on, until the right edge is located; then turn to the Y direction and move one step and take a photo, then slowly move one step in the -X direction and take a photo, and so on, until the left edge is located; then turn to the Y direction and move one step and take a photo; and repeat this cycle to obtain an image of the entire fiber cross section.

[0123] During the shooting process, the moving step length was set to 450 μm, and the editing program was used to automatically move the sample stage and continuously take pictures until all the fiber filaments were photographed.

[0124] S3: Automatic image recognition

[0125] The automatic image recognition process includes photo integration and fiber marking.

[0126] Step 3.1, photo integration: Import the fiber cross-section photos taken in S2 into the computer, and use the image analysis software OLYCIA m3 to integrate the photos of the entire fiber cross-section, remove the overlapping areas between the photos, and obtain a complete and accurate fiber cross-section.

[0127] Step 3.2, Fiber Marking: Open the metallographic software, select Add Fiber as a New Phase, and mark it red. Select the center of a fiber diameter. During the marking process, adjust the threshold to 150 until all fibers are marked red by the computer. After all fibers are identified and marked, use a counter to count the number of fibers. The calculator calculates the number of fibers to be 1185K.

[0128] S4: Calculation of fiber breakage rate

[0129] The number of fiber filaments in the fiber bundle used in the present invention is 12,000. The calculator counts the number of fiber filaments to be 11,348. According to the breakage rate calculation formula S=(mn) / m*100%, the fiber breakage rate is calculated to be (12,000-11,348) / 12,000*100%=5.43%.

[0130] m: the specified number of fiber filaments in the fiber bundle, n: the number of fiber filaments counted by a counter, and mn: the number of broken fiber filaments.

[0131] Example 3

[0132] S1: Sample preparation

[0133] A fiber bundle sample with a length of 30 mm was axially straightened and sequentially subjected to processes such as glue curing and manual combing, resin infiltration, gradient curing, metallographic mounting, wet grinding, and polishing to obtain the sample to be tested. The detailed steps are as follows:

[0134] Step 1.1, Glue Curing and Manual Combing: First, axially straighten a 30 mm long fiber bundle specimen. Apply adhesive along the base of the fiber bundle. Place the fiber bundle vertically and comb the fiber bundle from top to bottom with a comb to ensure vertical fiber alignment and avoid measurement errors caused by fiber bending or folding.

[0135] Step 1.2, Resin Infiltration: After the fibers have been cured and manually combed in Step 1.1, infiltrate them with epoxy resin for 20 minutes. Epoxy resin has low viscosity and high fluidity, ensuring complete separation of the fiber filaments and avoiding measurement errors caused by uneven infiltration.

[0136] Step 1.3, gradient curing: The fiber bundle after impregnation is cured by gradient curing. The first stage is to place it at room temperature (25°C) for 30 minutes to allow the resin to initially gel and avoid displacement or bending of the fiber during the transfer process.

[0137] The second stage: the fiber cured in the first stage is transferred to an oven and cured at 70°C for 1 hour to ensure that the resin is fully cross-linked and avoid shrinkage and deformation.

[0138] Step 1.4, metallographic mounting: After resin infiltration and curing, the fiber bundle specimen is cut into 15 mm specimens using a cutting machine equipped with a diamond grinding wheel. The cutting is cooled with water to ensure that there is no delamination or cracking on the test section.

[0139] The cut specimens are inlaid with metallographic inlay materials, embedded and solidified. Metallographic inlay can ensure that the fiber monofilaments are in an absolutely vertical dispersion state, avoiding fiber tilting or falling off during subsequent polishing. The high-hardness resin of metallographic inlay can withstand diamond polishing to ensure that the fiber cross section is not damaged.

[0140] During the mounting process, a small specimen clamp is used to hold the specimen to ensure that the specimen cross section is not skewed.

[0141] Step 1.5, wet grinding and polishing: The embedded sample is first wet-ground on a grinding machine from coarse to fine under running water, and then polished on a polishing machine using nylon polishing fabric and diamond polishing paste. The cross-section of the polished sample is clearly visible under a microscope, with no obvious fine line scratches.

[0142] S2: Obtaining fiber cross-section

[0143] The process of obtaining the fiber cross section includes: magnifying the fiber cross section and taking photos.

[0144] Step 2.1, Magnify the Fiber Cross-Section: First, place the polished sample on the sample stage of the laser confocal microscope. During placement, fill the bottom of the sample with plasticine to make the sample cross-section horizontal to ensure measurement accuracy. Select a microscope magnification of 500x.

[0145] Step 2.2, Photo Capture: The horizontal direction from left to right is defined as the +X direction, the vertical direction from top to bottom is defined as the Y direction, and the horizontal direction from right to left is defined as the -X direction. When photographing, start at the upper left edge of the fiber cross section, select a fiber at the rightmost edge of the image as a marker, slowly move one step in the +X direction and take a photo, and so on, until the right edge is located; then turn to the Y direction and move one step and take a photo, then slowly move one step in the -X direction and take a photo, and so on, until the left edge is located; then turn to the Y direction and move one step and take a photo; and repeat this cycle to obtain an image of the entire fiber cross section.

[0146] During the shooting process, the moving step length was set to 460 μm, and the editing program was used to make the sample stage move automatically and take pictures continuously until all the fiber filaments were photographed.

[0147] S3: Automatic image recognition

[0148] The automatic image recognition process includes photo integration and fiber marking.

[0149] Step 3.1, photo integration: Import the fiber cross-section photos taken in S2 into the computer, and use the image analysis software OLYCIA m3 to integrate the photos of the entire fiber cross-section, remove the overlapping areas between the photos, and obtain a complete and accurate fiber cross-section.

[0150] Step 3.2, Fiber Marking: Open the metallographic software, select Add Fiber as a New Phase, and mark it red. Select the center of a fiber diameter. During the marking process, adjust the threshold to 250 until all fibers are marked red by the computer. After all fibers are identified and marked, use a counter to count the number of fibers. The calculator calculates the number of fibers to be 1185K.

[0151] S4: Calculation of fiber breakage rate

[0152] The number of fiber filaments in the fiber bundle used in the present invention is 12,000. The calculator counts the number of fiber filaments to be 11,310. According to the breakage rate calculation formula S=(mn) / m*100%, the fiber breakage rate is calculated to be (12,000-11,310) / 12,000*100%=5.75%.

[0153] m: the specified number of fiber filaments in the fiber bundle, n: the number of fiber filaments counted by a counter, and mn: the number of broken fiber filaments.

[0154] Example 4

[0155] S1: Sample preparation

[0156] A fiber bundle sample with a length of 30 mm was axially straightened and sequentially subjected to processes such as glue curing and manual combing, resin infiltration, gradient curing, metallographic mounting, wet grinding, and polishing to obtain the sample to be tested. The detailed steps are as follows:

[0157] Step 1.1, Glue Curing and Manual Combing: First, axially straighten a 30 mm long fiber bundle specimen. Apply adhesive along the base of the fiber bundle. Place the fiber bundle vertically and comb the fiber bundle from top to bottom with a comb to ensure vertical fiber alignment and avoid measurement errors caused by fiber bending or folding.

[0158] Step 1.2, Resin Infiltration: After the fibers have been cured and manually combed in Step 1.1, infiltrate them with epoxy resin for 13 minutes. Epoxy resin has low viscosity and high fluidity, ensuring complete separation of the fiber filaments and avoiding measurement errors caused by uneven infiltration.

[0159] Step 1.3, gradient curing: The impregnated fiber bundle is cured by gradient curing. The first stage is to place it at room temperature (20°C) for 70 minutes to allow the resin to initially gel and avoid displacement or bending of the fiber during the transfer process.

[0160] The second stage: the fiber that has been cured in the first stage is transferred to an oven and cured at 60°C for 1.5 hours to ensure that the resin is fully cross-linked and avoid shrinkage and deformation.

[0161] Step 1.4, metallographic mounting: After resin infiltration and curing, the fiber bundle specimen is cut into 8 mm specimens using a cutting machine equipped with a diamond grinding wheel. The specimens are cooled with water during cutting to ensure that there is no delamination or cracking on the test section.

[0162] The cut specimens are inlaid with metallographic inlay materials, embedded and solidified. Metallographic inlay can ensure that the fiber monofilaments are in an absolutely vertical dispersion state, avoiding fiber tilting or falling off during subsequent polishing. The high-hardness resin of metallographic inlay can withstand diamond polishing to ensure that the fiber cross section is not damaged.

[0163] During the mounting process, a small specimen clamp is used to hold the specimen to ensure that the specimen cross section is not skewed.

[0164] Step 1.5, wet grinding and polishing: The embedded sample is first wet-ground on a grinding machine from coarse to fine under running water, and then polished on a polishing machine using nylon polishing fabric and diamond polishing paste. The cross-section of the polished sample is clearly visible under a microscope, with no obvious fine line scratches.

[0165] S2: Obtaining fiber cross-section

[0166] The process of obtaining the fiber cross section includes: magnifying the fiber cross section and taking photos.

[0167] Step 2.1, Magnify the Fiber Cross-Section: First, place the polished sample on the sample stage of the laser confocal microscope. During placement, fill the bottom of the sample with plasticine to make the sample cross-section horizontal to ensure measurement accuracy. Select a microscope magnification of 500x.

[0168] Step 2.2, Photo Capture: The horizontal direction from left to right is defined as the +X direction, the vertical direction from top to bottom is defined as the Y direction, and the horizontal direction from right to left is defined as the -X direction. When photographing, start at the upper left edge of the fiber cross section, select a fiber at the rightmost edge of the image as a marker, slowly move one step in the +X direction and take a photo, and so on, until the right edge is located; then turn to the Y direction and move one step and take a photo, then slowly move one step in the -X direction and take a photo, and so on, until the left edge is located; then turn to the Y direction and move one step and take a photo; and repeat this cycle to obtain an image of the entire fiber cross section.

[0169] During the shooting process, the moving step length was set to 470 μm, and the editing program was used to make the sample stage move automatically and take pictures continuously until all the fiber filaments were photographed.

[0170] S3: Automatic image recognition

[0171] The automatic image recognition process includes photo integration and fiber marking.

[0172] Step 3.1, photo integration: Import the fiber cross-section photos taken in S2 into the computer, and use the image analysis software OLYCIA m3 to integrate the photos of the entire fiber cross-section, remove the overlapping areas between the photos, and obtain a complete and accurate fiber cross-section.

[0173] Step 3.2, Fiber Marking: Open the metallographic software, select Add Fiber as a New Phase, and mark it red. Select the center of a fiber's diameter. During the marking process, adjust the threshold to 180 until all fibers are marked red by the computer. Once all fibers are identified and marked, use a counter to count the number of fibers. The calculator calculates 1185K fibers.

[0174] S4: Calculation of fiber breakage rate

[0175] The number of fiber filaments in the fiber bundle used in the present invention is 12,000. The calculator counts the number of fiber filaments to be 11,315. According to the breakage rate calculation formula S=(mn) / m*100%, the fiber breakage rate is calculated to be (12,000-11,315) / 12,000*100%=5.71%.

[0176] m: the specified number of fiber filaments in the fiber bundle, n: the number of fiber filaments counted by a counter, and mn: the number of broken fiber filaments.

[0177] Example 5

[0178] S1: Sample preparation

[0179] A fiber bundle sample with a length of 30 mm was axially straightened and sequentially subjected to processes such as glue curing and manual combing, resin infiltration, gradient curing, metallographic mounting, wet grinding, and polishing to obtain the sample to be tested. The detailed steps are as follows:

[0180] Step 1.1, Glue Curing and Manual Combing: First, axially straighten a 30 mm long fiber bundle specimen. Apply adhesive along the base of the fiber bundle. Place the fiber bundle vertically and comb the fiber bundle from top to bottom with a comb to ensure vertical fiber alignment and avoid measurement errors caused by fiber bending or folding.

[0181] Step 1.2, Resin Infiltration: After the fibers have been cured and manually combed in Step 1.1, infiltrate them with epoxy resin for 18 minutes. Epoxy resin has low viscosity and high fluidity, ensuring complete separation of the fiber filaments and avoiding measurement errors caused by uneven infiltration.

[0182] Step 1.3, gradient curing: The impregnated fiber bundle is cured by gradient curing. The first stage is to place it at room temperature (24°C) for 50 minutes to allow the resin to initially gel and avoid displacement or bending of the fiber during the transfer process.

[0183] The second stage: the fiber cured in the first stage is transferred to an oven and cured at 40°C for 2.5 hours to ensure that the resin is fully cross-linked and avoid shrinkage and deformation.

[0184] Step 1.4, metallographic mounting: After resin infiltration and curing, the fiber bundle specimen is cut into 12 mm specimens using a cutting machine equipped with a diamond grinding wheel. The cutting is cooled with water to ensure that there is no delamination or cracking on the test section.

[0185] The cut specimens are inlaid with metallographic inlay materials, embedded and solidified. Metallographic inlay can ensure that the fiber monofilaments are in an absolutely vertical dispersion state, avoiding fiber tilting or falling off during subsequent polishing. The high-hardness resin of metallographic inlay can withstand diamond polishing to ensure that the fiber cross section is not damaged.

[0186] During the mounting process, a small specimen clamp is used to hold the specimen to ensure that the specimen cross section is not skewed.

[0187] Step 1.5, wet grinding and polishing: The embedded sample is first wet-ground on a grinding machine from coarse to fine under running water, and then polished on a polishing machine using nylon polishing fabric and diamond polishing paste. The cross-section of the polished sample is clearly visible under a microscope, with no obvious fine line scratches.

[0188] S2: Obtaining fiber cross-section

[0189] The process of obtaining the fiber cross section includes: magnifying the fiber cross section and taking photos.

[0190] Step 2.1, Magnify the Fiber Cross-Section: First, place the polished sample on the sample stage of the laser confocal microscope. During placement, fill the bottom of the sample with plasticine to make the sample cross-section horizontal to ensure measurement accuracy. Select a microscope magnification of 500x.

[0191] Step 2.2, Photo Capture: The horizontal direction from left to right is defined as the +X direction, the vertical direction from top to bottom is defined as the Y direction, and the horizontal direction from right to left is defined as the -X direction. When photographing, start at the upper left edge of the fiber cross section, select a fiber at the rightmost edge of the image as a marker, slowly move one step in the +X direction and take a photo, and so on, until the right edge is located; then turn to the Y direction and move one step and take a photo, then slowly move one step in the -X direction and take a photo, and so on, until the left edge is located; then turn to the Y direction and move one step and take a photo; and repeat this cycle to obtain an image of the entire fiber cross section.

[0192] During the shooting process, the moving step length was set to 480 μm, and the editing program was used to automatically move the sample stage and continuously take pictures until all the fiber filaments were photographed.

[0193] S3: Automatic image recognition

[0194] The automatic image recognition process includes photo integration and fiber marking.

[0195] Step 3.1, photo integration: Import the fiber cross-section photos taken in S2 into the computer, and use the image analysis software OLYCIA m3 to integrate the photos of the entire fiber cross-section, remove the overlapping areas between the photos, and obtain a complete and accurate fiber cross-section.

[0196] Step 3.2, Fiber Marking: Open the metallographic software, select Add Fiber as a New Phase, and mark it red. Select the center of a fiber diameter. During the marking process, adjust the threshold to 220 until all fibers are marked red by the computer. After all fibers are identified and marked, use a counter to count the number of fibers. The calculator calculates the number of fibers to be 1185K.

[0197] S4: Calculation of fiber breakage rate

[0198] The number of fiber filaments in the fiber bundle used in the present invention is 12,000. The calculator calculates the number of fiber filaments to be 1,185K. According to the breakage rate calculation formula S=(mn) / m*100%, the fiber breakage rate is calculated to be (12,000-11,317) / 12,000*100%=5.69%.

[0199] m: the specified number of fiber filaments in the fiber bundle, n: the number of fiber filaments counted by a counter, and mn: the number of broken fiber filaments.

[0200] The parameter settings of different embodiments of the present invention are shown in Table 1.

[0201] Table 1. Parameter settings for different embodiments

[0202]

[0203] Comparative Example 1

[0204] For the fiber bundle of the same batch as Example 1 (the number of fiber filaments is 12,000), the number of fiber filaments counted manually is 11,321. According to the breakage rate calculation formula S = (mn) / m*100%, the fiber breakage rate is calculated as (12,000-11,321) / 12,000*100%=5.66%.

[0205] m: the specified number of fiber filaments in the fiber bundle, n: the number of fiber filaments counted by a counter, and mn: the number of broken fiber filaments.

[0206] The fiber breakage rate (5.66%) obtained by manual counting was used as a reference to calculate the deviation of the fiber breakage rate measured by the counter in the present invention. The calculation formula is:

[0207] (Breakage rate measured by this method - manual counting value) / Breakage rate measured by this method × 100%.

[0208] According to the above deviation calculation formula, the deviation results of different embodiments are calculated as shown in Table 2:

[0209] Table 2. Detected end-breakage rate results and deviations of different embodiments

[0210] Example 1 Example 2 Example 3 Example 4 Example 5 Fiber breakage rate 5.69％ 5.43％ 5.75％ 5.71％ 5.69％ deviation 0.53％ -4.24％ 1.57％ 0.88％ 0.53％

[0211] In summary, for the same batch of fiber bundles, the fiber breakage rates of Examples 1-5 measured using the method of the present invention were 5.43%-5.75%, which were different from the fiber breakage rate (5.66%) measured by manual counting in Control Example 1, as shown in Table 2. The deviation range was -4.24%-1.57%, and the deviations were all within 5%.

[0212] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for rapid detection of fiber breakage rate, characterized in that: The detection method comprises the following steps: S1: Sample preparation, including resin impregnation and curing of the treated fiber bundles, cutting and mounting, as well as wet grinding and polishing: S2: Obtaining the fiber cross section, including: magnifying the cross section of the fiber bundle until each fiber strand is clearly visible, taking multiple photos continuously until all fiber strand cross sections of the entire fiber bundle are obtained; S3: Automatic image recognition; including: automatically identifying and integrating the multiple photos taken in S2 to obtain a complete and accurate cross-sectional image of the fiber filaments; step 3.2: based on the color difference between the fiber and the resin, all the fiber filaments are marked by adjusting the threshold and the number of fiber filaments is counted; S4: Determine the fiber breakage rate based on the specified number of fiber filaments in the fiber bundle in S1 and the statistical number of fiber filaments obtained in S3.

2. The detection method according to claim 1, wherein The treatment includes axially straightening the fiber bundle, fixing the root of the fiber bundle, and combing the fiber bundle from top to bottom along the root of the fiber bundle; wherein an adhesive is used to be fixed by spot gluing along the root of the fiber bundle to place the fiber bundle vertically.

3. The detection method according to claim 2, characterized in that The fiber bundles are sequentially impregnated with resin and cured, cut and mounted, and wet-ground and polished, including: Step 1.2, infiltrating with uncured resin; curing with gradient curing; Step 1.3, cutting the fiber bundle into 5-15 mm specimens, and cold mounting the cut specimens; Step 1.4: First, wet-grind the embedded sample on a grinding machine from coarse to fine under running water, and then polish it on a polishing machine.

4. The detection method according to claim 3, characterized in that In step 1.2, the uncured resin includes epoxy resin and unsaturated polyester resin, preferably epoxy resin; the first stage of the gradient curing is: placing at 15-25°C for 30-90 minutes; the second stage is: transferring to an oven and curing at 30-70°C for 1-3 hours.

5. The detection method according to claim 3, characterized in that In the step 1.3, the cold mounting is performed using metallographic mounting materials.

6. The detection method according to claim 3, characterized in that In the step 1.4, the polishing materials are nylon polishing fabric and diamond polishing paste.

7. The detection method according to claim 1, characterized in that Automatically identifying and integrating the multiple photos taken in S2 includes: removing overlapping areas between the photos.

8. The detection method according to claim 1, wherein By adjusting the moving step length, all fiber filament cross sections of the entire fiber bundle are obtained; the moving step length is 450 to 480 μm.

9. The detection method according to claim 1, wherein In step 3.2, the fiber filaments are marked using metallographic software, and the threshold range is set to 150-250.

10. The detection method according to claim 1, characterized in that The calculation formula of broken ends rate is S=(mn) / m*100%; Here, m is the specified number of fiber filaments in the fiber bundle in S1, n is the number of fiber filaments counted by the counter obtained in S3, and mn is the number of broken fiber filaments.

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