Method and apparatus for adjusting the linear density of a fiber

Abstract

The application discloses a method and device for adjusting fiber linear density, and the method comprises the following steps: detecting the linear density value of the fiber, calculating the deviation value of the fiber linear density according to the theoretical center value of the fiber linear density and the detected fiber linear density value, and adjusting the glue output according to the deviation value of the fiber linear density. The application detects the linear density of the actually produced fiber, adjusts the glue output according to the deviation value of the fiber linear density, and then finely adjusts the linear density of the fiber, reduces the deviation between the linear density value of the actually produced fiber and the theoretical center value of the fiber linear density, maintains the stability of the fiber linear density, and improves the mechanical properties of the fiber.

Description

Technical Field

[0001] This invention belongs to the field of fiber production technology, specifically, it relates to a method and apparatus for adjusting fiber linear density. Background Technology

[0002] Carbon fiber is a special fiber composed of carbon elements. It possesses excellent properties such as high temperature resistance, friction resistance, electrical conductivity, thermal conductivity, and corrosion resistance, and can be processed into various fabrics. Due to its graphite microcrystalline structure preferentially oriented along the fiber axis, carbon fiber exhibits very high strength and modulus in this direction. Because of its low density, carbon fiber has high specific strength and specific modulus. The main application of carbon fiber is as a reinforcing material in composites with resins, metals, ceramics, and other carbon materials to manufacture advanced composite materials. Carbon fiber reinforced epoxy resin composites have the highest specific strength and specific modulus among existing engineering materials. Carbon fiber possesses excellent mechanical properties, and its main applications are in aerospace, military, and other fields.

[0003] In the actual production process of carbon fiber, a bundle of fibers consists of multiple monofilaments. The uniformity of fiber fineness is a crucial indicator. Generally, the fineness coefficient (CV) of the fiber needs to be strictly controlled within the quality standard range. A higher CV value indicates greater dispersion of the monofilaments, meaning the fiber thickness is less uniform, which in turn affects the mechanical properties of the carbon fiber filaments. Excessively thick or thin monofilaments are prone to breakage and fuzzing, impacting the overall mechanical properties of the fiber bundle. Reducing the CV value can improve the strength of carbon fiber. Among carbon fiber products produced using the same carbonization process, carbon fiber with a good CV value can achieve a strength of 4.2 GPA, while carbon fiber with a poor CV value struggles to reach 4.0 GPA. The uniformity of fiber linear density accurately characterizes fineness uniformity. In current fiber production processes, the actual linear density value of the produced fibers deviates significantly from the theoretical center value, affecting the performance of the carbon fiber.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method and apparatus for adjusting fiber linear density, which can adjust the fiber linear density during the fiber production process and reduce the deviation value of fiber linear density.

[0006] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0007] A method for adjusting fiber linear density involves detecting the fiber linear density value M, calculating the deviation value K of the fiber linear density based on the theoretical center value T of the fiber linear density and the detected fiber linear density value M, and adjusting the amount of adhesive dispensed based on the deviation value K of the fiber linear density.

[0008] Preferably, adjusting the control parameters based on the calculated fiber linear density deviation value K includes: obtaining a pre-set metering pump speed Ro; calculating a new metering pump speed Rn based on the calculated fiber linear density deviation value K and the metering pump speed Vo; and replacing the pre-set metering pump speed Ro with the new metering pump speed Rn, wherein the new metering pump speed Rn is:

[0009] Rn = Ro + Ro * K.

[0010] Preferably, after calculating the deviation value K of the fiber linear density, it is determined whether the deviation value K of the linear density is zero. If not, the amount of glue dispensed is adjusted according to the deviation value K of the fiber linear density.

[0011] Preferably, after calculating the deviation value K of the fiber linear density, it is determined whether the deviation value K of the fiber linear density is within a preset range. If not, the amount of glue dispensed is adjusted according to the deviation value K of the fiber linear density.

[0012] Another object of the present invention is to provide an apparatus for adjusting fiber linear density, comprising a parameter setting unit, a fiber production unit, and a linear density detection unit connected in sequence, wherein the linear density detection unit is connected to the parameter setting unit, and the apparatus employs a method for adjusting fiber linear density as described above.

[0013] Preferably, the parameter setting unit includes a logic operation module, the input end of which is connected to the linear density detection unit, and the output end of which is connected to the fiber production unit.

[0014] Preferably, the parameter setting unit includes a storage module that stores the control parameters of the fiber production unit, and the storage module is connected to the input terminal of the logic operation module.

[0015] Preferably, the fiber production unit includes a frequency converter and a metering pump. The signal input terminal of the frequency converter is connected to the parameter setting unit, and the signal output terminal of the frequency converter is connected to the metering pump.

[0016] Preferably, the linear density detection unit includes an electronic balance, which is communicatively connected to the parameter setting unit.

[0017] Preferably, the linear density detection unit includes a physical balance, and the parameter setting unit includes a manual input module, which is connected to the input terminal of the logic operation module.

[0018] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0019] This invention detects the linear density of the actually produced fibers and adjusts the speed of the metering pump based on the deviation in fiber linear density. This reduces the deviation between the actual linear density of the produced fibers and the theoretical center value of fiber linear density, maintaining the stability of fiber linear density and improving the mechanical properties of the fibers. Simultaneously, it reduces the frequency of spinneret and filter replacement, lowering equipment costs in fiber production. It also reduces manual labor intensity, decreasing the number of personnel required for spinneret replacement and further reducing labor costs in fiber production. The reduced frequency of spinneret replacement also reduces the volatilization of the coagulation bath, mitigating its environmental impact.

[0020] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0021] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0022] Figure 1 This is a schematic flowchart of a method for adjusting fiber linear density according to the present invention;

[0023] Figure 2 This is a schematic diagram of a device for adjusting fiber linear density according to the present invention.

[0024] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0026] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] like Figure 1 As shown in the figure, an embodiment of the present invention introduces a control method for adjusting fiber linear density, including: detecting the fiber linear density value M; calculating the deviation value K of the fiber linear density based on the theoretical center value T of the fiber linear density and the detected value M of the fiber linear density; and adjusting the amount of glue dispensed based on the deviation value K of the fiber linear density.

[0029] The linear density of a fiber represents the weight of a unit length of fiber. In this embodiment, the linear density of the fiber represents the weight of a one-meter-long fiber. During fiber production, the spinning solution delivered by the dosing unit is metered by a metering pump and then enters the spinneret. The spinneret has several spinneret orifices, and the fine stream of spinning solution extruded from these orifices enters the coagulation bath to form fibers. Typically, a filter screen is placed between the spinneret and the metering pump to filter impurities from the spinning solution. As the filter screen intercepts impurities in the spinning solution, a filter cake gradually forms, creating a certain degree of permeability resistance. This alters the amount of sizing agent produced, ultimately causing the linear density of the entire fiber bundle to deviate from the theoretical center value over time, resulting in a linear density deviation that severely affects the stability of fiber production. In traditional production processes, frequent replacement of the spinneret and filter screen is usually required, increasing both the intensity of manual operation and production costs. Furthermore, the evaporation from the coagulation bath during spinneret replacement can have an environmental impact.

[0030] This invention detects the linear density of the actually produced fibers and adjusts the glue output based on the deviation value K of the fiber linear density, maintaining a constant glue output and reducing the deviation between the actual produced fiber linear density value and the theoretical center value of the fiber linear density. This maintains the stability of the fiber linear density and improves the mechanical properties of the fiber. Simultaneously, it reduces the frequency of spinneret and filter replacement, lowering equipment costs for fiber production. It also reduces manual labor intensity, decreasing the number of personnel required for spinneret replacement and reducing labor costs in fiber production. Furthermore, the reduced frequency of spinneret replacement decreases the volatilization of the coagulation bath, mitigating its environmental impact.

[0031] In this embodiment of the invention, adjusting the dispensing amount based on the calculated deviation value K of the fiber linear density includes: obtaining a pre-set metering pump speed Ro; calculating a new metering pump speed Rn based on the calculated deviation value K of the fiber linear density and the metering pump speed Vo; and replacing the pre-set metering pump speed Ro with the new metering pump speed Rn, wherein the new metering pump speed Rn is:

[0032] Rn = Ro + Ro * K.

[0033] In this embodiment, the metering pump speed is used as a control parameter. By adjusting the metering pump speed, the flow rate of the metering pump can be changed, thereby changing the amount of glue produced. During the fiber production process, as the filter screen intercepts impurities in the spinning solution, a filter cake gradually forms, creating a certain amount of permeability resistance. This alters the amount of glue produced, ultimately causing the linear density of the entire fiber bundle to deviate from the theoretical center value as production time increases. This linear density deviation severely affects the stability of fiber production.

[0034] This invention calculates the deviation value K of fiber linear density to characterize the difference between the actual produced fiber and the theoretically expected produced fiber. Based on the deviation value K of fiber linear density and the set metering pump speed Ro, the metering pump speed is adjusted to change the glue output, thereby making the linear density of the produced fiber more stable.

[0035] In this embodiment of the invention, after calculating the deviation value K of the fiber linear density, it is determined whether the deviation value K of the linear density is zero. If not, the amount of glue dispensed is adjusted according to the deviation value K of the fiber linear density.

[0036] In this embodiment, the deviation value K of the fiber linear density is used as the qualification index of the fiber product. Only when the deviation value K of the fiber linear density is zero, that is, the actual produced fiber is completely consistent with the theoretical target, is it a qualified product; otherwise, it is an unqualified product. This invention determines whether the deviation value K of the linear density is zero. When the deviation value K of the fiber linear density is not zero, the amount of glue applied is adjusted according to the deviation value K, thereby fine-tuning the linear density of the fiber and improving the quality of the fiber product.

[0037] In this embodiment of the invention, after calculating the deviation value K of the fiber linear density, it is determined whether the deviation value K of the fiber linear density is within a preset range. If not, the amount of glue dispensed is adjusted according to the deviation value K of the fiber linear density.

[0038] In this embodiment, the deviation value K of fiber linear density is used as the qualification index of fiber products. A certain deviation in fiber linear density is allowed according to the needs of actual industrial production. If the deviation value K is within a preset range, the fiber product is considered qualified. This invention determines whether the deviation value K of fiber linear density is within the preset range. When the deviation value K exceeds the preset range, the amount of glue applied is adjusted based on the deviation value K, thereby fine-tuning the fiber linear density and improving the quality of the fiber product.

[0039] In this embodiment, the control method described in this invention is used to produce carbon fibers of various specifications, including 1K, 3K, 6K, 12K, 24K, 25K, 35K, 48K, and 50K carbon fibers, with single filament diameters ranging from 6 to 15 micrometers. For each specification of carbon fiber precursor, both the traditional carbon fiber precursor production method and the fiber linear density adjustment method described in this invention are employed. The linear density deviation and carbon filament strength are used as indicators to evaluate the quality of the carbon fiber precursor products. 1000 sets of control experiments were conducted for each specification of carbon fiber.

[0040] As shown in Table 1, the linear density deviation range of carbon fibers produced using traditional carbon fiber precursor production methods is 3.5-4.5%, while the linear density deviation range of carbon fibers produced using the fiber linear density adjustment method described in this invention is 1.7-2.0%. For 25K carbon fibers, the linear density deviation value was narrowed by 1.7% after using the fiber linear density adjustment method described in this invention, while for 48K carbon fibers, the linear density deviation value was narrowed by 2.5%. Compared with traditional carbon fiber precursor production methods, the linear density deviation fluctuation range was narrowed by 1.7-2.5% after using the fiber linear density adjustment method described in this invention.

[0041] Table 1 Comparison of Quality Indicators for Carbon Fiber Precursor Products -- Linear Density Deviation Value

[0042]

[0043]

[0044] As shown in Table 2, the strength of carbon filaments produced using traditional carbon fiber precursor production methods is 3.6-4.1 GPA, while the strength of carbon filaments produced using the fiber linear density adjustment method described in this invention is 3.9-4.4 GPA. For 24K carbon fibers, the strength of the carbon filaments increased by 0.1 GPA after using the fiber linear density adjustment method described in this invention, while for 48K carbon fibers, the strength increased by 0.4 GPA. Compared with traditional carbon fiber precursor production methods, the strength of the carbon filaments increased by 0.1-0.4 GPA after using the fiber linear density adjustment method described in this invention.

[0045] Table 2 Comparison of Quality Indicators for Carbon Fiber Precursor Products -- Carbon Fiber Strength

[0046]

[0047] like Figure 2 As shown in the illustration, this invention introduces a device for adjusting fiber linear density, comprising a parameter setting unit, a fiber production unit, and a linear density detection unit connected in sequence. The linear density detection unit is connected to the parameter setting unit, and the device employs a method for adjusting fiber linear density as described in the above embodiment. The fiber production unit includes a frequency converter and a metering pump. The signal input terminal of the frequency converter is connected to the parameter setting unit, and the signal output terminal of the frequency converter is connected to the metering pump.

[0048] In the fiber production process, the control parameters for fiber production must first be set. In this embodiment, the control parameters include the metering pump speed Ro, which is set by a parameter setting unit. After the control parameters are set, the parameter setting unit sends the set control parameters to the fiber production unit, which then produces fibers according to the received control parameters. Then, the linear density detection unit detects the produced fibers and measures the linear density value M. Based on the detected fiber linear density value M and the theoretical center value T of the fiber linear density, the fiber linear density deviation value K is calculated. The speed of the metering pump is then adjusted according to the calculated fiber linear density deviation value K.

[0049] This invention detects the linear density of the actually produced fibers and adjusts the metering pump speed based on the deviation value K of the fiber linear density. This reduces the deviation between the actual produced fiber linear density and the theoretical center value of the fiber linear density, maintaining the stability of the fiber linear density and improving the mechanical properties of the fiber. Simultaneously, it reduces the frequency of spinneret and filter replacement, lowering equipment costs for fiber production. It also reduces manual labor intensity, decreasing the number of personnel required for spinneret replacement and further reducing labor costs in fiber production. The reduced frequency of spinneret replacement also reduces the volatilization of the coagulation bath, mitigating its environmental impact.

[0050] In this embodiment of the invention, the parameter setting unit includes a logic operation module. The input terminal of the logic operation module is connected to the linear density detection unit, and the output terminal of the logic operation module is connected to the fiber production unit. The parameter setting unit also includes a storage module that stores control parameters of the fiber production unit, and the storage module is connected to the input terminal of the logic operation module.

[0051] After the detection unit detects the linear density value M of the fiber, it sends the detected value M to the parameter setting unit. The logic operation module in the parameter setting unit receives the detected linear density value M, retrieves the set metering pump speed Vo from the storage module, calculates the new metering pump speed Vn based on the detected linear density value M and the set speed Vo, and then inputs the new speed Vn into the frequency converter. The frequency converter adjusts the metering pump according to the new speed Vn, changes the glue output, reduces the deviation between the actual produced fiber linear density value and the theoretical center value of the fiber linear density, and maintains the stability of the fiber linear density.

[0052] In this embodiment of the invention, the linear density detection unit includes an electronic balance, which is communicatively connected to a parameter setting unit. After the fiber is wound up, the fiber is cut, and the electronic balance is used to detect the linear density value M of the cut fiber. Then, the electronic balance sends the detected fiber linear density value M to the parameter setting module for remote control modification of the control parameters.

[0053] In this embodiment of the invention, the linear density detection unit includes a physical balance, and the parameter setting unit includes a manual input module connected to the input terminal of the logic operation module. After the linear density value M of the fiber is detected using the physical balance, the operator calculates the deviation value K of the fiber linear density based on the detected value M and the theoretical value T of the fiber linear density. Then, the deviation value K is input to the logic operation module through the manual input module. The logic operation module calculates a new metering pump speed Vo and uses the metering pump speed Vo as a new control parameter. The frequency converter adjusts the metering pump according to the new metering pump speed Vo, changing the glue output and reducing the deviation between the actual produced fiber linear density value and the theoretical center value of the fiber linear density, thus maintaining the stability of the fiber linear density.

[0054] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0055] Except where at least some of such features and / or processes or units are mutually exclusive, any combination may be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or apparatus so disclosed. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0056] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for adjusting fiber linear density, characterized in that, The linear density value M of the fiber is detected. The deviation value K of the fiber linear density is calculated based on the theoretical center value T of the fiber linear density and the detected fiber linear density value M. The amount of glue is adjusted according to the deviation value K of the fiber linear density. The method of adjusting the dispensing amount is as follows: the dispensing amount is changed by adjusting the speed of the metering pump to change the flow rate of the metering pump. The step of adjusting the dispensing amount based on the fiber linear density deviation value K includes: obtaining a pre-set metering pump speed Ro; calculating a new metering pump speed Rn based on the calculated fiber linear density deviation value K and the metering pump speed Vo; and replacing the pre-set metering pump speed Ro with the new metering pump speed Rn, wherein the new metering pump speed Rn is: Rn = Ro + Ro * K.

2. The method for adjusting fiber linear density according to claim 1, characterized in that, After calculating the deviation value K of the fiber linear density, it is determined whether the deviation value K is zero. If not, the amount of glue dispensed is adjusted according to the deviation value K of the fiber linear density.

3. The method for adjusting fiber linear density according to claim 1, characterized in that, After calculating the deviation value K of the fiber linear density, determine whether the deviation value K of the fiber linear density is within the preset range. If not, adjust the amount of glue dispensed according to the deviation value K of the fiber linear density.

4. A device for adjusting fiber linear density, characterized in that, It includes a parameter setting unit, a fiber production unit, and a linear density detection unit connected in sequence. The linear density detection unit is connected to the parameter setting unit, and adopts a method for adjusting fiber linear density as described in any one of claims 1-3 above.

5. The device for adjusting fiber linear density according to claim 4, characterized in that, The parameter setting unit includes a logic operation module. The input of the logic operation module is connected to the linear density detection unit, and the output of the logic operation module is connected to the fiber production unit. The linear density detection unit detects the produced fibers and measures the linear density value M. The parameter setting unit calculates the fiber linear density deviation value K based on the detected fiber linear density value M and the theoretical center value T of the fiber linear density.

6. The device for adjusting fiber linear density according to claim 5, characterized in that, The parameter setting unit includes a storage module that stores the control parameters of the fiber production unit. The storage module is connected to the input terminal of the logic operation module, and the parameter setting unit completes the setting of the control parameters.

7. The device for adjusting fiber linear density according to claim 4, characterized in that, The fiber production unit includes a frequency converter and a metering pump. The signal input terminal of the frequency converter is connected to the parameter setting unit, and the signal output terminal of the frequency converter is connected to the metering pump. The linear density detection unit detects the produced fibers and measures the linear density value M. The parameter setting unit calculates the fiber linear density deviation value K based on the detected fiber linear density value M and the theoretical center value T of the fiber linear density, and adjusts the speed of the metering pump based on the calculated fiber linear density deviation value K.

8. The device for adjusting fiber linear density according to claim 5, characterized in that, The linear density detection unit includes an electronic balance, which is connected to a parameter setting unit. The parameter setting unit calculates Rn through a logic operation module. The fiber production unit includes a frequency converter and a metering pump. The frequency converter receives Rn and drives the metering pump to complete the speed adjustment.

9. The device for adjusting fiber linear density according to claim 5, characterized in that, The linear density detection unit includes a physical balance, and the parameter setting unit includes a manual input module, which is connected to the input terminal of the logic operation module. The parameter setting unit calculates Rn through the logic operation module. The fiber production unit includes a frequency converter and a metering pump. The frequency converter receives Rn and drives the metering pump to complete the speed adjustment.

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