Angle adjustment device for carbon fiber radial raman testing

Abstract

The utility model discloses an angle adjusting device for carbon fiber radial raman test, include: swing platform, the swing platform includes base and apron, the base detachably installs on the stage of raman spectrometer, the apron is swingably installed on the base in vertical direction, guide component, the guide component sets up between the base with the apron, drive assembly, drive assembly is connected with the guide component transmission, and drives the apron rotates the preset angle on the vertical plane in the guide stroke of guide component. In the use, the angle adjusting device is installed on the stage of raman spectrometer, and drive assembly drives apron to rotate, thereby driving the carbon fiber sample to be measured to fine tune proper angle, through the fine tuning of platform stage angle, overcome the test error problem caused by the axial deflection of sample, thereby improved the accuracy of carbon fiber radial raman test.

Description

Technical Field

[0001] This utility model relates to the field of auxiliary equipment for material testing, and specifically to an angle adjustment device for radial Raman testing of carbon fibers. Background Technology

[0002] Carbon fiber is a typical advanced material with high strength, high modulus, and corrosion resistance, and is widely used in aerospace, transportation, wind power equipment, and other fields. As a key reinforcement in high-performance composite materials, its final performance is not only affected by macroscopic chemical composition, but also significantly constrained by microstructure, especially the uniformity of radial structure. In recent years, research has found that PAN (polyacrylonitrile) based carbon fibers exhibit a distinct "skin-core structure" in the radial direction, meaning that the outer layer (skin) and the inner layer (core) show significant differences in structural order, graphitization degree, and defect distribution, which has become a key factor affecting the stability of carbon fiber mechanical properties.

[0003] Raman spectroscopy, as a non-destructive spectroscopic technique with high spatial resolution, has significant advantages in analyzing the structure of carbon materials, especially in probing the degree of graphitization within them. Currently, Raman testing typically involves vertically embedding carbon fiber bundles into resin, preparing cross-sectional samples after grinding and polishing, and then using a Raman instrument to scan radially to obtain spectra at different locations.

[0004] The aforementioned existing testing methods generally rely on manually ensuring that the carbon fiber bundles are vertically embedded in the resin during sample preparation to obtain a flat cross-section orthogonal to the optical axis. However, in practice, even after meticulous straightening and embedding, the carbon fiber bundles often still exhibit slight skewness (e.g., 0-5°). Such minute deviations amplify their error effects in high-resolution Raman spectroscopy, causing the laser irradiation angle to deviate from the vertical direction during radial scanning, thus affecting the comparison of spectra at different radial positions. Raman spectroscopy equipment platforms are typically fixed structures, lacking the ability to adapt to complex angle calibrations. Therefore, current radial structure Raman spectroscopy suffers from measurement point offset issues due to fiber axis tilt, making it difficult to accurately reflect the true differences in the carbon fiber core-sheath structure.

[0005] Therefore, an angle adjustment device for radial Raman testing of carbon fibers is provided, which aims to overcome the testing error caused by the axial deviation of the sample by finely adjusting the angle of the platform carrying surface, thereby improving the accuracy of radial Raman testing of carbon fibers. Utility Model Content

[0006] Therefore, this utility model provides an angle adjustment device for radial Raman testing of carbon fibers to solve at least one of the above-mentioned technical problems.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An angle adjustment device for radial Raman testing of carbon fibers, comprising:

[0009] A swing platform, comprising a base and a cover plate, wherein the base is detachably mounted on the stage of a Raman spectrometer, and the cover plate is swingably mounted on the base in the vertical direction;

[0010] A guide assembly disposed between the base and the cover plate;

[0011] A drive assembly is connected to the guide assembly and drives the cover plate to rotate at a preset angle in a vertical plane within the guide stroke of the guide assembly.

[0012] In operation, the angle adjustment device is mounted on the stage of the Raman spectrometer. The drive assembly rotates the guide rail, causing the cover plate to swing at a certain angle. The carbon fiber sample to be tested is placed in the center area of ​​the cover plate on the swinging platform, ensuring that the carbon fiber cross-section faces upward and is aligned with the Raman laser path. The angle is finely adjusted along with the cover plate to ensure the sample reaches the designated testing position, thus correcting any deviation in the carbon fiber sample to a vertical state. This resolves the testing error caused by the axial deviation of the carbon fiber sample and improves the angle consistency of radial Raman testing. In this way, the angle adjustment device overcomes the testing error caused by the axial deviation of the sample by finely adjusting the angle of the platform's loading surface, thereby improving the accuracy of radial Raman testing of carbon fibers.

[0013] In some embodiments, the guiding component includes:

[0014] A guide rail, which is installed inside the base;

[0015] A slider is mounted on the cover plate and is slidably mounted on the guide rail.

[0016] In some embodiments, the guide rail is a dovetail groove guide rail.

[0017] In some embodiments, the driving component includes:

[0018] Knob;

[0019] A worm gear, wherein the knob is mounted on one end of the worm gear and is capable of driving the worm gear to rotate;

[0020] A worm gear is screwed to the worm, and a slider is mounted on the worm gear and rotates by a preset angle along the extension direction of the guide rail under the drive of the worm gear.

[0021] In some embodiments, the angle adjustment device for radial Raman testing of carbon fibers further includes a locking component.

[0022] In some embodiments, the locking component is a locking bolt.

[0023] In some embodiments, the sidewalls of the swing platform are provided with angle markings. Attached Figure Description

[0024] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0025] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0026] Figure 1 A schematic diagram of the angle adjustment device provided by this utility model;

[0027] Figure 2 One of the plan views of the angle adjustment device provided by this utility model;

[0028] Figure 3 A second plan view of the angle adjustment device provided by this utility model;

[0029] Figure 4 This is the third plan view of the angle adjustment device provided by this utility model;

[0030] Figure 5 Fourth plan view of the angle adjustment device provided by this utility model;

[0031] Figure 6 Fifth plan view of the angle adjustment device provided by this utility model;

[0032] Figure 7 This is the sixth plan view of the angle adjustment device provided by this utility model;

[0033] Figure 8 This is an exploded view of the angle adjustment device provided by this utility model;

[0034] Figure 9This is a schematic diagram of the support device provided by the present invention;

[0035] Figure 10 This is a schematic diagram of multiple test points in the radial Raman test in the embodiment;

[0036] Figure 11 This is a schematic diagram of Raman spectrum peak fitting in the example;

[0037] Figure 12 This is a schematic diagram of the sample block obtained by embedding carbon fiber in epoxy resin in the comparative example.

[0038] Figure 13 The image shows the Raman spectrum at point 1 of sample CF1 in the comparative example.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1-Swing platform, 11-Base, 12-Cover plate;

[0041] 2-Dovetail groove guide rail;

[0042] 31-Knob, 32-Worm, 33-Worm Gear, 34-Locking Bolt;

[0043] 4-Angle markings;

[0044] 5-Support device. Detailed Implementation

[0045] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0046] In one specific implementation, such as Figures 1-9As shown, the angle adjustment device for radial Raman testing of carbon fibers provided by this utility model includes a swing platform 1, a guide assembly, and a drive assembly. The swing platform 1 includes a base 11 and a cover plate 12. The base 11 is detachably mounted on the stage of the Raman spectrometer. The cover plate 12 is vertically swingable and mounted on the base 11. The guide assembly is disposed between the base 11 and the cover plate 12. The drive assembly is connected to the guide assembly and drives the cover plate 12 to rotate a preset angle in the vertical plane within the guide stroke of the guide assembly. By driving the cover plate 12 to rotate through the drive assembly, the angle of the swing platform 1 is adjusted, ensuring that the carbon fiber sample to be tested can be adjusted to a vertical state, thereby improving the accuracy of the radial Raman test.

[0047] During use, the angle adjustment device is installed on the stage of the Raman spectrometer. The drive assembly rotates the guide rail, causing the cover plate 12 to swing at a certain angle. The carbon fiber sample to be tested is installed in the center area of ​​the cover plate 12 on the swing platform 1, ensuring that the carbon fiber cross-section faces upward and is in the direction of the Raman laser beam. The angle is finely adjusted with the cover plate 12 to ensure that the sample reaches the designated test position, thereby adjusting the skewed carbon fiber sample to a vertical state. This solves the test error caused by the axial deviation of the carbon fiber sample and improves the angle consistency of radial Raman testing. In this way, the angle adjustment device overcomes the test error problem caused by the axial deviation of the sample by finely adjusting the angle of the platform's carrying surface, thereby improving the accuracy of radial Raman testing of carbon fiber.

[0048] Furthermore, the sample is embedded in epoxy resin to form a resin block, which is then bonded and fixed to the surface of the cover plate 12. The lower surface of the resin block is in contact with the upper surface of the swing platform 1, and a stable connection is achieved with the help of an adhesive. Thus, when the swing platform 1 swings and adjusts, the carbon fiber sample can maintain a synchronous adjustment angle.

[0049] The guide assembly includes a guide rail and a slider. The guide rail is installed inside the base 11, and the slider is installed on the cover plate 12. The slider is slidably mounted on the guide rail.

[0050] Preferably, the guide rail is a dovetail groove guide rail 2, which features high precision and high stability, ensuring smooth sliding of the slider and improving the accuracy of angle adjustment. Theoretically, the guide rail can also be a T-shaped guide rail or other high-precision guide rail structures.

[0051] Specifically, the drive assembly includes a knob 31, a worm gear 32, and a worm wheel 33. The knob 31 is mounted on one end of the worm gear 32 and can drive the worm gear 32 to rotate. The worm wheel 33 is screwed to the worm gear 32. The slider is mounted on the worm wheel 33 and rotates by a preset angle along the extension direction of the guide rail under the drive of the worm wheel 33. The worm gear drive has self-locking properties, which can ensure that the adjusted angle remains stable and improve the stability and reliability of the device. Obviously, the drive assembly can adopt gear transmission or lead screw transmission, and the angle adjustment can be achieved through a corresponding control mechanism.

[0052] Furthermore, the angle adjustment device also includes a locking assembly, specifically a locking bolt 34. The locking assembly ensures the stability of the swing platform 1 after adjustment to the desired angle, preventing angle deviation due to vibration or other factors during testing. The locking bolt 34 has a simple structure, is easy to operate, and effectively locks the slider or swing platform 1, ensuring stability during testing.

[0053] Furthermore, the side wall of the swing platform 1 is provided with angle markings 4. The angle markings 4 allow operators to easily and precisely adjust the angle, improving the convenience and accuracy of operation.

[0054] To facilitate understanding, the following uses a specific application scenario as an example to describe the overall structure of the angle adjustment device provided by this utility model, the process of using the angle adjustment device to perform Raman testing, and to verify the technical effect of the angle adjustment device in improving the accuracy of Raman testing through a comparative example.

[0055] Please continue to refer to this. Figures 1-8 This invention provides an angle adjustment device for radial Raman testing of carbon fibers, including a small swing platform 1 with a single-axis micro-angle adjustment structure. The swing platform 1 can be embedded in the stage of a Raman spectrometer, and the slot at the bottom of the swing platform 1 is connected to... Figure 9 The support device 5 shown is fixed with screws and then attached to the Raman stage with double-sided tape. The swing platform 1 has a swing adjustment capability of ±5°, which is used to fine-tune the axial angle of the sample so that the cross-section of the carbon fiber bundle (test surface) is perpendicular to the laser incident direction.

[0056] like Figure 1 As shown, compared with traditional fixed stages, this device introduces mechanical rotational freedom, allowing experimenters to make high-precision adjustments based on the actual deflection angle of the sample. The platform's internal oscillation structure, based on a dovetail guide rail 2 driven by a worm gear, is designed for angle adjustment and correction. Employing a precision bearing system and locking mechanism, it achieves continuous and controllable angular oscillation with a locking function, ensuring the platform's stability remains undisturbed during testing after adjustment.

[0057] Specifically, the swing platform 1 of the angle adjustment device is made of brass and has a standard slot at the bottom, which can be embedded in the stage of the Renishaw inVia Raman spectrometer. The table size of the swing platform 1 is about 25mm×25mm and the swing center height is about 40±0.1mm, ensuring that the function can be nested without changing the original system structure.

[0058] The swing platform 1 achieves ±5° swing through the dovetail groove guide rail 2. The rotation adjustment is controlled by the knob 31 on the side, which is equipped with angle scale markings and locking bolts 34 to ensure that the device is stable and has no displacement after adjustment.

[0059] Based on the aforementioned angle adjustment device, the process of performing cross-sectional structural analysis of PAN-based carbon fiber CF1 using the radial Raman spectroscopy method includes the following steps:

[0060] 1. Sample preparation.

[0061] A bundle of CF1 carbon fibers (approximately 1 k strands) was prepared as a complete cross-sectional test sample in the following manner:

[0062] (1) Straightening and wrapping: Take the fiber and wrap it around a small winding frame, moisten it with water or ethanol and straighten it, and fix it with tape;

[0063] (2) Impregnation treatment: Gently shake in the composite adhesive solution for 3 minutes to complete the impregnation. The adhesive solution formula is: 500g of E51 epoxy resin, 422.5g of curing agent (including 7.5g of accelerator), 650g of acetone, and cured at 120℃ for 4 hours.

[0064] (3) Embedding: The epoxy resin (CER 1000) and the anhydride curing agent (CEH 500) are mixed in a 2:1 ratio and cured in the mold at 70°C for 2 hours to complete the first embedding; after demolding, it is embedded again and cured at 70°C for 3 hours to obtain a complete fiber cross-section block.

[0065] (4) Grinding and polishing: Grind step by step using P400, P1000 and P5000 sandpaper, and finally polish with 250nm diamond polishing agent until the cross-sectional structure of a single carbon fiber can be clearly observed under an optical microscope.

[0066] (5) Ultrasonic cleaning: Ultrasonic cleaning in anhydrous ethanol at 100kHz frequency and 200W power for 30 minutes to remove surface impurities.

[0067] The obtained epoxy resin embedded block was placed on a horizontal platform. By placing a ruler vertically on the platform, the angle between the carbon fiber axis and the ruler was observed and measured. It was calculated that the carbon fiber sample had an axial deviation of about 5° relative to the vertical direction.

[0068] Therefore, before testing, the sample was placed on a Raman stage equipped with a small swing platform 1. By adjusting the angle of the swing platform 1, the sample axis was corrected from a skewed state to be perpendicular to the horizontal plane (the skew angle was adjusted from about 5° to close to 0°).

[0069] 2. Raman test conditions.

[0070] A Renishaw inVia Raman spectrometer was used, with an excitation wavelength of 514 nm, a laser intensity set to 10%, and a spot diameter of approximately 0.7 μm. A 100× microscope objective was used for focusing. Figure 10 In the multiple test points shown, the exposure time for each test point is 3 seconds, for a total of 10 tests. The scanning range is 800-2050 cm. -1 .

[0071] Five equally spaced radial test points were selected on the cross-section of a single carbon fiber, and Raman spectra were measured sequentially from the edge to the center, as shown below. Figure 11 The diagram shows a schematic of Raman spectrum peak fitting. Peak parameters D1, D2, D3, and G were extracted through multi-peak fitting, and the D1 / G area ratio (R = AD1 / AG) was calculated to assess the degree of graphitization.

[0072] 3. Results and Analysis.

[0073] After angle correction, the scanning path of the light spot on the cross-section of the carbon fiber is more vertical and uniform, and the obtained Raman spectrum shows a smoother gradient distribution of R values ​​in the radial direction, with clear transition rules between regions. CF1 exhibits a significant structural gradient in the radial direction, with lower R values ​​in the edge region, indicating a high degree of graphitization; and higher R values ​​in the central region, reflecting enhanced internal disorder.

[0074] As a comparative example, the radial Raman test procedure for carbon fiber sample CF1 without using a calibration platform is briefly described below.

[0075] like Figure 12 As shown, without using a calibration platform, the prepared carbon fiber cross-section sample was directly placed on the stage of the Raman instrument for testing. Due to a slight axial deviation (approximately 5°) during sample embedding, the carbon fiber axis was not completely perpendicular to the laser incident direction, causing the Raman radial scanning path to deviate from the fiber cross-section.

[0076] When performing Raman radial testing, five equally spaced test points were selected on the cross-section, and the scan was performed sequentially from one edge to the other. The following anomaly was observed in the test results:

[0077] At the first point, such as Figure 13As shown, due to the tilt of the sample cross-section relative to the horizontal plane, the laser will be partially focused on the epoxy resin region. Although the D / G peak can be observed in the obtained Raman spectrum, the baseline is obviously raised ("float"), indicating that the signal is severely affected by the fluorescence interference of the resin.

[0078] At the second point, corresponding to the carbon fiber skin, the laser incident angle was not perpendicular to the cross section due to the skew effect, resulting in the effective excitation area being partially focused on the edge skin, and the R value obtained by fitting the spectrum was slightly smaller.

[0079] The third point should have corresponded to the middle transition region of the fiber, but due to the angle error, the laser detection area shifted to the area closer to the skin, and the resulting spectrum showed that the R value was smaller than the corrected corresponding position.

[0080] The fourth point corresponds to the transition zone, but the actual test point is offset. The laser part detects the boundary between the core and the transition zone, and the R value is larger than the corresponding position after correction.

[0081] The fifth point is close to the other side edge. Due to the overall tilt of the radial scanning trajectory, the laser part at this point is focused on the core region, the D peak in the spectrum is enhanced, and the R value is larger than the corresponding position after correction.

[0082] The test results show that radial Raman scanning under the condition of 5° skewness of carbon fiber sample will cause the Raman laser focusing position to be inconsistent with the ideal radial path, which will significantly affect the spectral characteristics and R value change trend of each point, resulting in systematic errors in the radial structure evaluation results and making it difficult to truly reflect the differences in the core-skin structure.

[0083] In summary, current Raman spectroscopy tests for radial inhomogeneity in carbon fibers primarily employ a method of preparing cross-sectional samples by vertically embedding fiber bundles into resin, followed by radial scanning using a Raman instrument. While this method is widely used, ensuring the fiber axis remains perpendicular to the laser incident direction during sample preparation is challenging, especially in batch preparations where sample skew angles are difficult to control, typically exhibiting axial errors within 5°. Because the Raman spot's focusing area is extremely small (approximately 0.7 μm), this minute skew significantly affects the actual interaction path between the laser and the carbon fiber cross-section, causing the scanning point position to deviate from the ideal radial path. This results in noticeable spectral drift, abnormal fluctuations in the D / G peak area ratio, and ultimately, impacts the analysis of the core-skin structure.

[0084] This invention effectively solves the aforementioned problems by introducing a small, adjustable angle calibration platform. Based on a single-axis micro-oscillator design, the platform allows for precise adjustment of the sample stage angle within a 0-5° range, thereby correcting skewed carbon fiber samples to a vertical position. The device is compact and can be directly embedded into the stage of a conventional Raman instrument without affecting existing operating procedures. Experiments show that after angle calibration using this platform, the Raman radial scan spectrum distribution is more reasonable, the R-value variation trend is more consistent with physical laws, and the repeatability and comparability of the test data are significantly improved, truly reflecting the radial structural characteristics of carbon fibers.

[0085] Therefore, in the above specific embodiments, the technical solution proposed by this utility model has the following technical advantages and beneficial effects:

[0086] (1) It solved the systematic test error caused by the axial deviation of carbon fiber samples and improved the angular consistency of radial Raman test;

[0087] (2) It improves the stability of Raman spectra, enhances the repeatability and comparability of radial structure parameters, and can be used to finely characterize the evolution law of core-skin structure.

[0088] (3) The device is small in size, highly versatile, and easy to install. It can be integrated with existing Raman spectroscopy platforms, making it easy to promote and apply.

[0089] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above are only specific embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of this utility model should be included within the scope of protection of this utility model.

Claims

1. An angle adjustment device for carbon fiber radial Raman testing, characterized by, include: A swing platform, comprising a base and a cover plate, wherein the base is detachably mounted on the stage of a Raman spectrometer, and the cover plate is swingably mounted on the base in the vertical direction; A guide assembly disposed between the base and the cover plate; A drive assembly is connected to the guide assembly and drives the cover plate to rotate at a preset angle in a vertical plane within the guide stroke of the guide assembly.

2. The angle adjustment device for carbon fiber radial Raman testing according to claim 1, characterized by, The guiding component includes: A guide rail, which is installed inside the base; A slider is mounted on the cover plate and is slidably mounted on the guide rail.

3. The angle adjustment device for carbon fiber radial Raman testing according to claim 2, characterized in that, The guide rail is a dovetail groove guide rail.

4. The angle adjustment device for carbon fiber radial Raman testing according to claim 2, characterized by, The driving component includes: Knob; A worm gear, wherein the knob is mounted on one end of the worm gear and is capable of driving the worm gear to rotate; A worm gear is screwed to the worm, and a slider is mounted on the worm gear and rotates by a preset angle along the extension direction of the guide rail under the drive of the worm gear.

5. The angle adjustment device for carbon fiber radial Raman testing according to claim 4, characterized in that, It also includes a locking component.

6. The angle adjustment device for carbon fiber radial Raman testing according to claim 5, characterized by, The locking component is a locking bolt.

7. The angle adjustment device for carbon fiber radial Raman testing of claim 1, wherein, The sidewall of the swing platform is provided with angle markings.

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