Preparation method and preparation device of large-tow carbon fiber section test sample

Abstract

The invention discloses a preparation method and a preparation device of a large-tow carbon fiber cross section test sample, the preparation method of the large-tow carbon fiber cross section test sample comprises the following steps: S1, arranging carbon fiber tows: rearranging strip-shaped carbon fiber tows into columnar carbon fiber tows, and keeping monofilament fibers basically parallel, the clamp is convenient to clamp; s2, the carbon fiber tows are clamped and fixed through a non-glue clamp; s3, two-section type cutting: in the first step of cutting, the carbon fiber tows at the two ends of the non-glue clamp are cut off, tension-free carbon fiber tow sections are obtained, and the non-glue clamp for clamping and fixing the carbon fiber tows is taken out; s4, two-section type cutting; S5, to-be-measured section cleaning; S6, sample drying; and S7, observation. According to the method, the defects of a traditional sample preparation method can be overcome, and the cross section of the prepared sample is free of glue solution pollution, compact in carbon fiber tow, neat and flat, clean and free of cutting disintegrating slag.

Description

Technical Field

[0001] The invention belongs to the technical field of material performance testing, and in particular relates to a preparation method and a preparation device for a large-tow carbon fiber cross-section test sample. Background Art

[0002] Carbon fiber is a high-performance synthetic material with a carbon content of more than 90%. It is usually made by high-temperature cracking of organic fibers and has a diameter of about (5-10) μm. Carbon fiber is "lightweight and high-strength" with a specific gravity of only about 1 / 5 of that of steel and a strength of 5-7 times that of steel. It has the characteristics of high temperature resistance, corrosion resistance, and good conductivity. It is an ideal choice to replace traditional metal materials and is one of the strongest commercial fibers known to date. It is widely used in aerospace, automotive, sports equipment and other fields.

[0003] The cross-sectional morphology and diameter test of carbon fiber is an important indicator of carbon fiber factory inspection and an important parameter for measuring carbon fiber performance. Sample preparation is the key to the cross-sectional morphology and diameter test of carbon fiber. The current mainstream sample preparation methods are mainly the following:

[0004] Method 1: The carbon fiber tow provides tensile tension, a conductive tape is bundled in the tension area, and the bundled area is cut to obtain a carbon fiber cross-section sample.

[0005] Method 2: The carbon fiber tow is in a tension-free state. The carbon fiber tow is cut and lightly pressure is applied at the cut point to fix the carbon fiber tow. The carbon fiber tow is cut at a position about 5 mm away from the fracture. This surface is the observation section. The sample is pasted on the conductive glue to obtain a carbon fiber cross-section sample. The observation section is adjusted to be perpendicular to the lens barrel of the scanning electron microscope for observation.

[0006] Method 3, making a composite material of carbon fiber tow and resin matrix, and cutting and grinding the cross section to make a carbon fiber cross-section sample.

[0007] However, the above method has the following defects:

[0008] The main defect of method 1 is that the conductive adhesive may be cut during the sample preparation process, and the sample cross section may be contaminated by the conductive adhesive, leading to misjudgment and unqualified test results.

[0009] The main defects of method 2 are the lack of lateral restraint, loose and uneven tow samples, and the lack of sufficient fiber samples in the field of view for testing during magnified observation.

[0010] The main drawback of method 3 is that the resin is introduced during the sample preparation process, which cannot reflect the true situation of the carbon fiber tow. The resin has poor conductivity. When using a scanning electron microscope for observation, the sample cross section needs to be coated with a layer of metal film, which is complicated to operate and affects the accuracy of the test results.

[0011] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0012] The purpose of the present invention is to provide a preparation method and preparation device for a large-tow carbon fiber cross-section test sample, which can overcome the shortcomings of traditional sample preparation methods and obtain the sample cross-section: no glue pollution, tight carbon fiber tows, neat and flat cross-section, clean cross-section without cutting debris.

[0013] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0014] A method for preparing a large-tow carbon fiber cross-section test sample comprises the following steps:

[0015] S1. Arrange the carbon fiber tows: rearrange the "ribbon-shaped" carbon fiber tows into "columnar" carbon fiber tows, while keeping the single filament fibers basically parallel to facilitate clamping;

[0016] S2, a non-glue fixture clamps and fixes the carbon fiber tow;

[0017] S3, two-stage cutting, the first step of cutting: cutting the carbon fiber tows at both ends of the glue-free clamp to obtain the tension-free carbon fiber tow segments, and taking out the glue-free clamp that clamps and fixes the carbon fiber tow;

[0018] S4, two-stage cutting, second step cutting: the single-sided blade is close to the glue-free fixture, and the carbon fiber tow is cut at the junction of the clamping force and the non-clamping force to obtain a flat cross section to be measured;

[0019] S5, cleaning the section to be measured: placing the sample prepared in the above step S4 in a cleaning solvent and ultrasonically cleaning it;

[0020] S6, sample drying: the sample cleaned in step S5 is placed in a vacuum oven for drying;

[0021] S7. Observation: Place the sample in the sample chamber of the scanning electron microscope and adjust the cross section to be perpendicular to the scanning electron microscope barrel for observation.

[0022] In one or more embodiments of the present invention, in the S4 step, if the amount of sizing on the surface of the carbon fiber sample is large, the sizing agent sticks to the surface of the blade during the cutting process and is smeared onto the cutting surface as the blade moves, contaminating the cutting surface. The glue-free fixture in step S3 is taken out and frozen with liquid nitrogen before performing step S4.

[0023] In one or more embodiments of the present invention, the cleaning solvent in step S5 includes pure water and ethanol.

[0024] In one or more embodiments of the present invention, the cross section of the sample dried in step S6 can be purged with high-pressure gas to further clean the cross section.

[0025] A preparation device for a large-tow carbon fiber cross-section test sample comprises a pay-off roller, a first guide roller, a second guide roller and a third guide roller, wherein the pay-off roller, the first guide roller, the second guide roller and the third guide roller are arranged and fixed in sequence, a water trough is arranged on one end face of the second guide roller, a wire cutting system is arranged on one end face of the third guide roller, and a fourth guide roller and a wire collecting roller are arranged on one end face of the cutting system in sequence.

[0026] In one or more embodiments of the present invention, the first guide wire roller, the second guide wire roller and the third guide wire roller are sequentially provided with a first arc groove, a second arc groove and a third arc groove, and the diameters of the first arc groove, the second arc groove and the third arc groove decrease sequentially.

[0027] In one or more embodiments of the present invention, the water tank is filled with three-level water.

[0028] In one or more embodiments of the present invention, the wire cutting system includes a wire cutting platform, a non-glue clamp, a pair of wire cutting tools and a pair of clamping devices. The wire cutting platform is located on one side end face of the third wire guide roller; the non-glue clamp is located on the upper side end face of the wire cutting platform, and the non-glue clamp is used to clamp the carbon fiber bundle; a pair of opposite end faces at the top of the non-glue clamp are both provided with wire cutting tools; a pair of clamping devices are provided on the top end face of the non-glue clamp, and the pair of clamping devices are respectively located on the outer side end faces of the pair of wire cutting tools.

[0029] In one or more embodiments of the present invention, the adhesive-free clamp includes an adhesive-free clamp groove base, an adhesive-free clamp bearing beam, and an upper pressure head. The adhesive-free clamp groove base is located on the upper end surface of the wire cutting platform; the adhesive-free clamp bearing beam is located on the upper end surface of the adhesive-free clamp groove base, and the adhesive-free clamp bearing beam is provided with a thread, and the thread is threadedly connected with a screw; the bottom end surface of the adhesive-free clamp bearing beam is connected to the upper pressure head, and the upper pressure head is fixedly connected with the screw.

[0030] In one or more embodiments of the present invention, the top end surface of the upper pressure head is fixedly connected to a rotary joint, the bottom end surface of the screw is fixedly connected to the rotary joint, and the top end surface of the screw is provided with a hexagonal screw hole.

[0031] Compared with the prior art, the method and device for preparing a large-tow carbon fiber cross-section test sample of the present invention have the following benefits:

[0032] 1) This sample preparation method does not use glue, which can avoid glue contaminating the sample cross section.

[0033] 2) This sample preparation method uses a two-stage cutting method: the first step of cutting eliminates the tension of the carbon fiber tow, and the second step of cutting is performed without tensile stress, which can solve the problem of "uneven" length of the cross-section fibers; the second step of cutting the interface can solve the problem of uneven cross-section. Two-step cutting can obtain a neat and flat cross-section.

[0034] 3) Overcoming the shortcomings of traditional sample preparation methods, the sample cross-section obtained is: no glue pollution, the carbon fiber tow is tight, the cross-section is neat and flat, the cross-section is clean and free of cutting debris, the operation is simple, and it does not affect the accuracy of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 This is a schematic structural diagram of a device for preparing a large-tow carbon fiber cross-section test sample in one embodiment of the present invention;

[0037] Figure 2 is a top view of a carbon fiber tow in one embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of a "ribbon-shaped" cross section of a carbon fiber shipped from a factory in one embodiment of the present invention;

[0039] Figure 4 It is a schematic cross-sectional view of a carbon fiber tow during the shaping process of a godet roller in one embodiment of the present invention;

[0040] Figure 5 It is a schematic diagram of the cross section of a carbon fiber tow after being shaped by a godet roller in one embodiment of the present invention;

[0041] Figure 6 It is a schematic diagram of a cross section of a carbon fiber tow in a glue-free fixture according to an embodiment of the present invention;

[0042] Figure 7 is a schematic cross-sectional view of a carbon fiber tow in one embodiment of the present invention;

[0043] Figure 8 A top view of a glue-free clamp in one embodiment of the present invention;

[0044] Fig. 9 A side view of a glue-free clamp in one embodiment of the present invention;

[0045] Fig.10 Schematic diagram of cutting in step S4 in one embodiment of the present invention;

[0046] Fig.11 It is a partial structural schematic diagram of a first wire guide roller in one embodiment of the present invention;

[0047] Fig.12 It is a partial structural schematic diagram of the second wire guide roller in one embodiment of the present invention;

[0048] Fig.13 Schematic diagram of the partial structure of the third wire guide roller in one embodiment of the present invention.

[0049] Description of main reference numerals:

[0050] 1-wire release roller, 2-carbon fiber tow, 3-first wire guide roller, 301-first arc groove, 4-second wire guide roller, 401-second arc groove, 5-water trough, 6-third wire guide roller, 601-third arc groove, 7-clamping device, 8-wire cutting tool, 9-wire cutting platform, 10-glueless clamp, 101-hexagonal screw hole, 102-glueless clamp bearing beam, 103-screw, 104-thread, 105-swivel joint, 106-upper pressure head, 107-glueless clamp groove base, 11-fourth wire guide roller, 12-wire collection roller. DETAILED DESCRIPTION

[0051] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0052] The sample in this embodiment is a 48K large-tow carbon fiber sample with a high sizing amount.

[0053] The sample cross section obtained by the traditional sample preparation method 1 has the following problems: some areas of the cross section are contaminated by the conductive glue and cannot be tested; the cross section flatness is poor, and the cross section of some monofilament fibers is uneven; more than half of the cross section is covered by cutting debris and cannot be observed.

[0054] The sample cross section obtained by the traditional sample preparation method 2 has the following problems: the carbon fiber tow is loose, and there is not enough fiber sample in the field of view when magnified for observation, and it cannot be tested; the cross section flatness is poor and the length of the single fiber is uneven; there are many cross section cutting debris. The cross section sample obtained by method 2 can only be used to observe the cross section morphology of the carbon fiber, and cannot be used to measure the diameter.

[0055] The measurement results of the cross-section samples prepared by the traditional sample preparation method 3 are only used as a reference and cannot be used as a basis for factory inspection of carbon fiber.

[0056] In order to reduce production costs, large-tow carbon fiber products such as 48K are the development trend of the carbon fiber industry. Traditional sample preparation methods cannot meet the sample preparation needs. In order to solve the above problems, the sample preparation method of the present invention is selected to overcome the shortcomings of traditional sample preparation methods. The cross-section of the prepared sample has no glue pollution, the carbon fiber tow is tight, the cross-section is neat and flat, and the cross-section is clean without cutting debris.

[0057] like Figure 1 As shown, a method for preparing a large-tow carbon fiber cross-section test sample in one embodiment of the present invention comprises the following steps:

[0058] S1. Arrangement of carbon fiber tows: The carbon fiber samples to be tested are generally "ribbon-shaped" carbon fiber tows [such as Figure 3 The state of the carbon fiber tow is shown in the figure. The single filament fibers are basically parallel. The "ribbon-shaped" carbon fiber tow is rearranged to become a "column-shaped" carbon fiber tow, while keeping the single filament fibers basically parallel to facilitate clamping;

[0059] S2, the glue-free fixture 10 clamps and fixes the carbon fiber tow [such as Figure 6 The state of the carbon fiber tow is shown];

[0060] S3, two-stage cutting, the first step of cutting: cutting the carbon fiber tows at both ends of the glue-free clamp 10, obtaining the tension-free carbon fiber tow segments, and taking out the glue-free clamp 10 that clamps and fixes the carbon fiber tow;

[0061] S4, two-stage cutting, second step of cutting: a single-sided blade is pressed against the glue-free fixture 10, and the carbon fiber tow is cut at the junction of the clamping force and the non-clamping force to obtain a flat cross section to be measured;

[0062] Furthermore, if the amount of sizing on the surface of the carbon fiber sample is large, the sizing agent will stick to the blade surface during the cutting process and be smeared onto the cutting surface as the blade moves, polluting the cutting surface. After the glue-free fixture 10 in step S3 is taken out, it is first frozen with liquid nitrogen, and then step S4 is performed.

[0063] S5. Cleaning the section to be measured: placing the sample prepared in the above step S4 in a cleaning solvent for ultrasonic cleaning.

[0064] Preferably, the cleaning solvent includes pure water and ethanol.

[0065] S6. Sample drying: The sample cleaned in step S5 is placed in a vacuum oven for drying.

[0066] Optionally, after the sample is dried, the cross section may be purged with high pressure gas to further clean the cross section.

[0067] S7. Observation: Place the sample in the sample chamber of the scanning electron microscope and adjust the cross section to be perpendicular to the scanning electron microscope barrel for observation. Figure 7 The state of the carbon fiber tow is shown].

[0068] like Figure 2 As shown, it is a schematic diagram of the overall processing shape of the carbon fiber tow 2 during the S1-S7 process.

[0069] like Figure 1-10 As shown, a preparation device for a large-tow carbon fiber cross-section test sample includes a pay-off roller 1, a first guide roller 3, a second guide roller 4 and a third guide roller 6. The pay-off roller 1, the first guide roller 3, the second guide roller 4 and the third guide roller 6 are arranged and fixed in sequence, a water trough 5 is arranged on one end face of the second guide roller 4, a wire cutting system is arranged on one end face of the third guide roller 6, and a fourth guide roller 11 and a wire collecting roller 12 are arranged on one end face of the wire cutting system in sequence.

[0070] Specifically, the carbon fiber sample to be tested is generally a "ribbon-shaped" carbon fiber tow, and the single filament fibers are basically parallel. The carbon fiber sample is fixed on a wire-releasing roller 1, and a carbon fiber tow 2 is drawn out, and the cross-section is as follows: Figure 2 As shown. The carbon fiber tow 2 passes through the first guide roller 3, the second guide roller 4, and the third guide roller 6, and the carbon fiber tow 2 is gradually gathered. Figure 3-Figure 5 The following are schematic diagrams of the cross-sections before, during and after the carbon fiber tows are gathered.

[0071] Furthermore, the first wire guide roller 3, the second wire guide roller 4 and the third wire guide roller 6 are respectively provided with a first arc groove 301, a second arc groove 401 and a third arc groove 601, and the diameters of the first arc groove 301, the second arc groove 401 and the third arc groove 601 are successively reduced, so that the wire guiding process can gradually gather the carbon fiber tow 2 along the cross-sectional direction perpendicular to the tow.

[0072] The water tank 5 is filled with three-level water. When the carbon fiber tow 2 passes through the second guide roller 4, it soaks the carbon fiber tow. The liquid tension plays a bundling role, which is conducive to the carbon fiber tow 2 gathering along the cross-sectional direction perpendicular to the tow. The carbon fiber tow 2 is clamped and fixed by the glue-free clamp 10.

[0073] The wire cutting system includes a wire cutting platform 9, a non-glue clamp 10, a pair of wire cutting knives 8 and a pair of clamping devices 7. The wire cutting platform 9 is located on one side end surface of the third wire guide roller 6; the non-glue clamp 10 is located on the upper side end surface of the wire cutting platform 9, and the non-glue clamp 10 is used to clamp the carbon fiber tow 2. The carbon fiber tow 2 is located between the wire cutting platform 9 and the non-glue clamp 10. The wire cutting platform 9 is used to provide a reaction force to fix the carbon fiber tow 2.

[0074] A pair of opposite end surfaces at the top of the glue-free clamp 10 are both provided with wire cutting tools 8 , which are symmetrically distributed to cut the carbon fiber tow 2 .

[0075] A pair of clamping devices 7 are arranged on the top end surface of the glue-free clamp 10 , and the pair of clamping devices 7 are symmetrically distributed on the outer end surfaces of a pair of wire cutting tools 8 . The clamping devices 7 move up and down to fix the carbon fiber tow 2 .

[0076] The glue-free clamp 10 includes a glue-free clamp groove base 107, a glue-free clamp bearing beam 102 and an upper pressure head 106. The glue-free clamp 10 is used to clamp and fix the carbon fiber tow 2. The shape of the carbon fiber tow 2 in the glue-free clamp 10 is as follows: Figure 6 The glue-free clamp 10 is preferably made of metal.

[0077] The non-glue clamp groove base 107 is located on the upper end surface of the slitting platform 9 , and the non-glue clamp groove base 107 provides a reaction force to cut the carbon fiber tow 2 at both ends of the non-glue clamp 10 .

[0078] The glue-free clamp support beam 102 is located at the upper end surface of the glue-free clamp groove base 107. A thread 104 is opened in the glue-free clamp support beam 102. The thread 104 is threadedly connected with a screw 103. The bottom end surface of the glue-free clamp support beam 102 is connected to an upper pressure head 106. The upper pressure head 106 is fixedly connected to the screw 103.

[0079] Furthermore, the top end face of the upper pressing head 106 is fixedly connected to the rotating joint 105, and the bottom end face of the screw 103 is fixedly connected to the rotating joint 105, so that the rotating joint 105 can be driven to move by rotating the screw 103, thereby driving the upper pressing head 106 to move downward to clamp and fix the carbon fiber bundle 2.

[0080] A hexagonal screw hole 101 is formed on the top end surface of the screw 103 , and a hexagonal screw hole 101 can be connected to fix a hexagonal wrench to control the rotation of the screw 103 .

[0081] Preferably, a limiting groove is provided inside the screw 103, a part of the end surface of the rotary joint 105 is located in the limiting groove, the screw 103 is fixedly connected to the rotary joint 105, and the rotary joint 105 can be fixed in the screw 103 by welding.

[0082] A groove is provided on the non-glue fixture groove base 107, and the groove matches the carbon fiber tow 2, and the carbon fiber tow 2 runs through the groove. The wire cutting tool 8 includes a blade, and the blade is used for cutting.

[0083] When in use, the screw 103 is connected to the upper pressure head 106 through the rotary joint 105, and the hexagonal wrench is inserted into the hexagonal screw hole 101. Turning the screw 103 can drive the upper pressure head 106 to move up and down. After the carbon fiber tow 2 passes through the groove of the non-glue clamp groove base 107, the screw 103 is turned with a hexagonal wrench to drive the upper pressure head 106 to move down and clamp the carbon fiber tow 2. The clamping and fixing state is as shown in FIG. Fig. 9 As shown;

[0084] The symmetrically distributed clamping device 7 moves downward, and the wire cutting platform 9 provides a reaction force to fix the carbon fiber bundle 2. The symmetrically distributed wire cutting tool 8 moves downward, and the wire cutting platform 9 provides a reaction force to cut the carbon fiber bundle 2 at both ends of the glue-free clamp 10. The glue-free clamp 10 that clamps and fixes the carbon fiber bundle 2 is removed.

[0085] Since the sample contains a large amount of sizing agent, the sizing agent adheres to the surface of the blade of the slitting tool 8 during the cutting process, and is smeared onto the cutting surface as the blade moves, contaminating the cutting surface. Cryogenic cutting is required, and the specific operation is as follows: the glue-free clamp 10 removed above for clamping and fixing the carbon fiber tow 2 is placed in an oven for drying, and then frozen with liquid nitrogen. After freezing, a single-sided blade is used to press against the glue-free clamp 10, and the carbon fiber tow 2 is cut at the junction of the clamping force and the non-clamping force. The cutting diagram is shown in the figure. Fig.10 As shown;

[0086] The cut samples are placed in pure water or ethanol or other solvents for ultrasonic cleaning;

[0087] After cleaning, the sample is placed in a vacuum oven to dry. After drying, the cross section is purged with high-pressure gas to further clean the cross section, and the sample preparation is completed.

[0088] Place the sample in the sample chamber of the scanning electron microscope and adjust the cross section to be perpendicular to the scanning electron microscope barrel for observation.

[0089] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0090] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a large-tow carbon fiber cross-section test sample, characterized in that: The steps include: S1. Arrange the carbon fiber tows: rearrange the "ribbon-shaped" carbon fiber tows into "column-shaped" carbon fiber tows, while keeping the single filament fibers basically parallel to facilitate clamping; S2, a non-glue fixture clamps and fixes the carbon fiber tow; S3, two-stage cutting, the first step of cutting: cutting the carbon fiber tows at both ends of the glue-free clamp to obtain the tension-free carbon fiber tow segments, and taking out the glue-free clamp that clamps and fixes the carbon fiber tow; S4, two-stage cutting, second step cutting: the single-sided blade is close to the glue-free fixture, and the carbon fiber tow is cut at the junction of the clamping force and the non-clamping force to obtain a flat cross section to be measured; S5, cleaning the section to be measured: placing the sample prepared in the above step S4 in a cleaning solvent and ultrasonically cleaning it; S6, sample drying: the sample cleaned in step S5 is placed in a vacuum oven for drying; S7. Observation: Place the sample in the sample chamber of the scanning electron microscope and adjust the cross section to be perpendicular to the scanning electron microscope barrel for observation.

2. The method for preparing a large-tow carbon fiber cross-section test sample according to claim 1, characterized in that: In step S4, if the amount of sizing on the surface of the carbon fiber sample is large, the sizing agent will stick to the surface of the blade during the cutting process and be smeared onto the cutting surface as the blade moves, polluting the cutting surface. The glue-free fixture 10 in step S3 is taken out and frozen with liquid nitrogen before performing step S4.

3. The method for preparing a large-tow carbon fiber cross-section test sample according to claim 1, characterized in that: The cleaning solvent in step S5 includes pure water and ethanol.

4. The method for preparing a large-tow carbon fiber cross-section test sample according to claim 1, characterized in that: After the sample is dried in step S6, the cross section can be purged with high-pressure gas to further clean the cross section.

5. A preparation device for a large-tow carbon fiber cross-section test sample, applicable to the preparation method for a large-tow carbon fiber cross-section test sample according to any one of claims 1 to 4, characterized in that: It includes a wire-releasing roller, a first wire-guiding roller, a second wire-guiding roller and a third wire-guiding roller, wherein the wire-releasing roller, the first wire-guiding roller, the second wire-guiding roller and the third wire-guiding roller are arranged and fixed in sequence, one end face of the second wire-guiding roller is provided with a water trough, one end face of the third wire-guiding roller is provided with a wire cutting system, and one end face of the wire cutting system is provided with a fourth wire-guiding roller and a wire-collecting roller in sequence.

6. The device for preparing a large-tow carbon fiber cross-section test sample according to claim 6, characterized in that: The first wire guide roller, the second wire guide roller and the third wire guide roller are all provided with a first arc groove, a second arc groove and a third arc groove in sequence, and the diameters of the first arc groove, the second arc groove and the third arc groove decrease in sequence.

7. The device for preparing a large-tow carbon fiber cross-section test sample according to claim 6, characterized in that: The water tank is filled with three-level water.

8. A method and device for preparing a large-tow carbon fiber cross-section test sample according to claim 5 or 6, characterized in that: The shredding system comprises: A wire cutting platform is located on one side end surface of the third wire guide roller; A non-glue clamp is located on the upper end surface of the slitting platform, and is used to clamp the carbon fiber tow; A pair of slitting cutters, wherein a pair of opposite end surfaces at the top of the glue-free clamp are both provided with slitting cutters; A pair of clamping devices are arranged on the top end surface of the glue-free clamp, and the pair of clamping devices are respectively located on the outer end surfaces of a pair of shredding knives.

9. A method and device for preparing a large-tow carbon fiber cross-section test sample according to claim 8, characterized in that: The glue-free fixture includes: The non-glue fixture groove base is located on the upper end surface of the slitting platform; The glue-free clamp load beam is located on the upper end surface of the glue-free clamp groove base, and the glue-free clamp load beam is provided with a thread, and the thread is threadedly connected with a screw; An upper pressing head, the bottom end surface of the adhesive-free clamp bearing beam is connected to the upper pressing head, and the upper pressing head is fixed with screws.

10. A method and device for preparing a large-tow carbon fiber cross-section test sample according to claim 9, characterized in that: The top end surface of the upper pressure head is fixedly connected with a rotary joint, the bottom end surface of the screw is fixedly connected with the rotary joint, and the top end surface of the screw is provided with a hexagonal screw hole.

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