Preparation method of fixed-length continuous fiber

Abstract

The invention discloses a preparation method of fixed-length continuous fibers. Aiming at the pre-twisted fibers, firstly plying N fiber yarns to enable the N fiber yarns to be combined into a group of mutually attached fiber yarns, then enabling the group of fiber yarns to pass through a twisting device, twisting the N yarns to form mutually interwoven and wound single-strand fiber yarns, cutting off N-1 fiber yarns at fixed length, and finally forming a shaft again by utilizing a yarn collecting roller; for non-pre-twisted fibers, the non-pre-twisted fibers are broadened firstly, the two sides of the non-pre-twisted fibers are subjected to fixed-length half cutting, only the fiber continuity of the middle area is reserved, and then the non-pre-twisted fibers are collected to form a shaft so as to be used in the next procedure. According to the invention, the twisted fiber yarn is cut at fixed length, so that the traditional preparation mode that the unit layers of the preform need to be connected by a mesh tire is changed, the preparation procedures of the preform are reduced, the preparation time and the preparation cost of the preform are reduced, and the industrial competitiveness of a preform production enterprise is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of textile weaving, and in particular relates to a method for preparing fixed-length continuous fibers. Background Art

[0002] Fiber mesh is an important raw and auxiliary material in the preparation of needle punched preforms. Its preparation process is complicated and the process is cumbersome. The product quality itself has a great influence on the uniformity of the preform. In addition, since the mesh is cut and laid in pieces, wrinkles often occur, especially for non-developable surfaces, wrinkles, cavities and other problems are more serious. The above shortcomings seriously restrict the preparation cost and molding quality of the preform, so it is urgent to design a new type of fiber structure to replace the mesh in the preform preparation process. Summary of the invention

[0003] The purpose of the present invention is to solve the problem that the specific gravity of the web is too high in the preparation of the needle-punched preform, which restricts the high-quality and low-cost development of the needle-punched preform, and provide a method for preparing a fixed-length continuous fiber.

[0004] In order to achieve the purpose of the present invention, the present invention provides the following technical solutions:

[0005] A method for preparing a fixed-length continuous fiber comprises the following steps:

[0006] Step 1: For the pre-twisted characteristic fiber, firstly, N pre-twisted characteristic fiber yarns are subjected to yarn hanging, tensioning, and yarn guiding processes, wherein the pre-twisted characteristic fiber yarns include pre-twisted characteristic fiber main yarns and pre-twisted characteristic fiber auxiliary yarns;

[0007] Step 2: Ply N pre-twisted characteristic fiber main yarns and pre-twisted characteristic fiber auxiliary yarns, bind them into a group of yarns, and then pass through a plying roller to enter a twisting device;

[0008] Step 3: Twist the plied yarn and spray a certain sizing agent to bind the pre-twisted characteristic fiber auxiliary yarn and spirally interweave to wrap the pre-twisted characteristic fiber main yarn together;

[0009] Step 4: passing the twisted yarn bundle through a short-cut device, cutting the pre-twisted characteristic fiber auxiliary yarn at the periphery of the twisted yarn at a fixed length, retaining the continuity of the pre-twisted characteristic fiber main yarn at the center of the twisted yarn bundle, and obtaining a fixed-length continuous fiber;

[0010] Step 5: The fixed-length continuous fiber is rewound onto the fiber drum and stored.

[0011] A method for preparing a fixed-length continuous fiber comprises the following steps:

[0012] Step 1: For non-pre-twisted characteristic fibers, a single non-pre-twisted characteristic fiber yarn is subjected to yarn hanging, tensioning, and yarn guiding processes;

[0013] Step 2: widen the single non-pre-twisted characteristic fiber yarn through a widening process, so that it is flattened and spread out to form a two-dimensional plane with a certain area;

[0014] Step 3: The non-pre-twisted characteristic fiber yarn after widening is passed through a short-cut device, and the short-cut device cuts the non-pre-twisted characteristic fiber yarn at half length on both sides after widening, and only retains the fiber continuity in the middle area to obtain a fixed-length continuous fiber;

[0015] Step 4: The fixed-length continuous fiber is rewound onto the fiber drum and stored.

[0016] Furthermore, in step 1, N is greater than or equal to 3.

[0017] Furthermore, the pre-twisted characteristic fibers in step 2 are quartz fibers, alumina fibers, and zirconia fibers.

[0018] Furthermore, the twisting method in step 3 is a wrapping twisting method.

[0019] Furthermore, the pre-twisted characteristic fiber auxiliary yarn in step 4 is the Z-direction fiber in the needle-punched preform.

[0020] Furthermore, the non-pre-twisted fibers are carbon fibers.

[0021] Furthermore, the short cutting device is a ring knife, a chopping knife or a raising loop.

[0022] Further, the short cutting device is a ring knife device, which includes a ring knife, a bracket, a motor I, a motor II, a motor III, an active roller, a driven roller I, and a driven roller II. The ring knife is installed on the bracket, and the motor I, motor II, and motor III are fixed on the bracket. The motor I, motor II, and motor III are respectively connected to the active roller, the driven roller I, and the driven roller II. The active roller, the driven roller I, and the driven roller II are rollers with grooves, which are located on the edge of the ring knife and can drive the ring knife to rotate. The ring knife includes an inner opening and an outer opening. The inner opening of the ring knife passes through the ring knife, and the outer opening of the ring knife is arranged at the surface of the ring knife. The inner opening of the ring knife is located at the surface of the ring knife, and the diameter of the outer opening of the ring knife is larger than the diameter of the inner opening of the ring knife.

[0023] Furthermore, the short-cut device comprises two ring knife devices, and the two ring knife devices are paired together. By adjusting the distance between the two ring knife devices, the length of the fixed-length fibers in the fixed-length continuous fibers can be changed.

[0024] Furthermore, when the two ring knife devices are paired together, the inner openings of the two ring knives are staggered to ensure that the two ring knives can chop the two sides of the fiber respectively, and the staggered displacement distance is less than or equal to the radius of the inner opening of the ring knife.

[0025] Compared with the prior art, the significant improvements of the present invention are: 1) the preparation of the needle-punched preform can be carried out without a mesh, which greatly reduces the preparation cost of the needle-punched preform; 2) the fiber cloth woven from a fixed-length fiber bundle provided by the present invention can provide a Z-direction layer connection effect that is no less than that of a mesh; 3) it solves the current situation of cumbersome procedures and complex preparation processes of raw and auxiliary materials in the preparation of needle-punched preforms; 4) it simplifies the preparation process of the needle-punched preform and improves the production quality of the needle-punched preform. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0027] Figure 1 A diagram showing a method for forming fixed-length fibers that are not pre-twisted fibers.

[0028] Figure 2 A diagram showing a method for forming a fixed-length fiber of pre-twisted fibers.

[0029] Figure 3 Schematic diagram of pre-twisted fixed-length fiber.

[0030] Figure 4 Schematic diagram of non-pre-twisted fixed-length fiber.

[0031] Figure 5 Schematic diagram of pairing ring knife devices in an embodiment.

[0032] Figure 6 Schematic diagram of a single ring knife device in the embodiment.

[0033] Figure 7 This is a schematic diagram of the misalignment of the inner opening of the ring knife in the matching ring knife device. DETAILED DESCRIPTION

[0034] Combination Figure 1 , 3 A method for preparing a fixed-length continuous fiber comprises the following steps:

[0035] Step 1: For the pre-twisted characteristic fiber, firstly, N pre-twisted characteristic fiber yarns are subjected to yarn hanging, tensioning, and yarn guiding processes, wherein the pre-twisted characteristic fiber yarns include pre-twisted characteristic fiber main yarns and pre-twisted characteristic fiber auxiliary yarns;

[0036] Step 2: Ply N pre-twisted characteristic fiber main yarns and pre-twisted characteristic fiber auxiliary yarns, bind them into a group of yarns, and then pass through the plying roller to enter the twisting device. The plying roller is used to ply the fibers and tension the fibers so that they are straight and have a certain tension when passing through the ring knife edge;

[0037] Step 3: Twist the plied yarn and spray a certain sizing agent to bind the pre-twisted characteristic fiber auxiliary yarn and spirally interweave to wrap the pre-twisted characteristic fiber main yarn together;

[0038] Step 4: passing the twisted yarn bundle through a short-cut device, cutting the pre-twisted characteristic fiber auxiliary yarn at the periphery of the twisted yarn at a fixed length, retaining the continuity of the pre-twisted characteristic fiber main yarn at the center of the twisted yarn bundle, and obtaining a fixed-length continuous fiber;

[0039] Step 5: The fixed-length continuous fiber is rewound onto the fiber drum and stored.

[0040] Preferably, in step 1, N is greater than or equal to 3.

[0041] Preferably, the pre-twisted characteristic fiber in step 2 is generally a high-strength fiber yarn with a high twist and a large number of strands, such as quartz fiber, alumina fiber, and zirconia fiber.

[0042] Preferably, the twisting method in step 3 is a wrapping twisting method.

[0043] Preferably, the pre-twisted characteristic fiber auxiliary yarn in step 4 is the Z-direction fiber in the needle-punched preform.

[0044] Combination Figure 2 , 4 A method for preparing a fixed-length continuous fiber comprises the following steps:

[0045] Step 1: For non-pre-twisted characteristic fibers, a single non-pre-twisted characteristic fiber yarn is subjected to yarn hanging, tensioning, and yarn guiding processes;

[0046] Step 2: widen the single non-pre-twisted characteristic fiber yarn through a widening process, so that it is flattened and spread out to form a two-dimensional plane with a certain area;

[0047] Step 3: The non-pre-twisted characteristic fiber yarn after widening is passed through a short-cut device, and the short-cut device cuts the non-pre-twisted characteristic fiber yarn at half length on both sides after widening, and only retains the fiber continuity in the middle area to obtain a fixed-length continuous fiber;

[0048] Step 4: The fixed-length continuous fiber is rewound onto the fiber drum and stored.

[0049] Preferably, the non-pre-twisted fibers are carbon fibers.

[0050] Preferably, the short-cutting device is only a short-cutting method for fixed-length continuous fibers. As long as the fibers can be cut into short pieces, they belong to the short-cutting method required by this solution, for example, it can be a ring knife, a chopping knife or a terry loop.

[0051] Preferably, combined Figure 5-6The short cutting device is a ring knife device, which includes a ring knife 1, a bracket 2, a motor Ⅰ3, a motor Ⅱ4, a motor Ⅲ5, an active roller 6, a driven roller Ⅰ7, and a driven roller Ⅱ8. The ring knife 1 is installed on the bracket 2, and the motors Ⅰ3, Ⅱ4, and Ⅲ5 are fixed on the bracket 2. The motors Ⅰ3, Ⅱ4, and Ⅲ5 are connected to the active roller 6, the driven roller Ⅰ7, and the driven roller Ⅱ8 respectively. The active roller 6, the driven roller Ⅰ7, and the driven roller Ⅱ8 are rollers with grooves, which are located at the edge of the ring knife 1 and can drive the ring knife 1 to rotate. The ring knife 1 includes an inner opening 1-1 and an outer opening 1-2. The inner opening 1-1 of the ring knife runs through the ring knife 1. The outer opening 1-2 of the ring knife is arranged on the surface of the ring knife 1 where the inner opening 1-1 of the ring knife is located. The diameter of the outer opening 1-2 of the ring knife is larger than that of the inner opening 1-1 of the ring knife. When working normally, the active roller 6 is driven to rotate by the motor Ⅰ3, thereby driving the driven roller Ⅰ7 and the driven roller Ⅱ8 to rotate through the ring knife 1, and the motor Ⅱ4 and the motor Ⅲ5 do not work. When the motor Ⅰ3 fails and cannot work, the motor Ⅱ4 or the motor Ⅲ5 can work. After the ring knife 1 rotates, the inner opening 1-1 of the ring knife can cut short the continuous fibers passing through it, thereby achieving the effect of preparing fixed-length continuous fibers. The bracket 6 is used to fix the motor Ⅰ3, the motor Ⅱ4, and the motor Ⅲ5 so that they do not move.

[0052] Preferably, the short-cut device comprises two annular knife devices, and the two annular knife devices are paired together, and the length of the fixed-length fibers in the fixed-length continuous fibers is changed by adjusting the distance between the two annular knife devices.

[0053] Preferably, combined Figure 7 When the two ring knife devices are paired together, the inner openings 1-1 of the two ring knives 1 are staggered to ensure that the two ring knives 1 can cut the two sides of the fiber respectively, and the staggered displacement distance is less than or equal to the radius of the inner opening 1 of the ring knife to ensure that the inner opening 1-1 of the ring knife will not completely cut the fixed-length continuous fiber.

[0054] Example 1

[0055] When it is necessary to produce a shaft of 380tex fixed-length continuous quartz fiber yarn, the specific implementation method is as follows

[0056] Step 1: For quartz fiber, firstly hang, tension and guide 4 95tex quartz fiber yarns, including quartz fiber main yarn and quartz fiber auxiliary yarn.

[0057] Step 2: Ply four 95tex quartz fiber main yarns and quartz fiber auxiliary yarns, bind them into a group of 380tex yarns, and then pass them into the twisting device through the plying roller.

[0058] Step 3: Twist the plied yarn and spray a certain amount of sizing agent to bind three 95tex quartz fiber auxiliary yarns and spirally interweave them to wrap one 95tex quartz fiber main yarn together;

[0059] Step 4: Pass the twisted yarn bundle through the circular knife device and start the circular knife device. The circular knife inside the circular knife device starts to rotate and move back and forth, and the twisted yarn bundle is continuously transmitted forward. Through this movement relationship, the three 95tex quartz fiber auxiliary yarns on the periphery of the twisted yarn are cut off at a fixed length, and only the continuity of the one 95tex quartz fiber main yarn in the center of the twisted yarn bundle is retained;

[0060] Step 5: The 380 tex fixed-length continuous quartz fiber is rewound onto the fiber drum and stored for the next process.

[0061] Example 2

[0062] When it is necessary to produce a shaft of 380tex fixed-length continuous carbon fiber yarn, the specific implementation method is as follows

[0063] Step 1: For carbon fiber, a single 380tex carbon fiber yarn is hung, tensioned, and guided.

[0064] Step 2: A single 380tex carbon fiber yarn is widened through a widening process so that it is flattened and spread out to form a two-dimensional plane with a certain area.

[0065] Step 3: Pass the widened single 380tex carbon yarn through the ring knife device, and start the ring knife device. The ring knife inside the ring knife device starts to rotate and move back and forth, and the twisted yarn bundle is continuously transmitted forward. Through this movement relationship, the ring knife device cuts the two sides of the unfolded carbon fiber yarn in half at a fixed length, leaving only the fiber continuity in the middle area;

[0066] Step 4: The 380tex fixed-length continuous carbon fiber is rewound onto the fiber drum and stored for the next process.

[0067] The present invention aims to solve the problem that the specific gravity of the web in the preparation of needle-punched preforms is too high, which restricts the high-quality and low-cost development of needle-punched preforms. The present invention provides a new type of fiber structure, in which general fiber bundles are partially short-cut to become continuous and partially separated long fiber bundles, and the fixed-length fiber bundles are used for weaving and directly used for preform needle-punching. The fabric has the continuous fiber cloth layer required for the preparation of the preform and the Z-direction fiber bundles that the web can provide, so that a qualified needle-punched preform can be prepared quickly and at low cost.

[0068] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0069] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a fixed-length continuous fiber, characterized in that: The following steps are involved: Step 1: For the pre-twisted characteristic fiber, firstly, N pre-twisted characteristic fiber yarns are subjected to yarn hanging, tensioning, and yarn guiding processes, wherein the pre-twisted characteristic fiber yarns include pre-twisted characteristic fiber main yarns and pre-twisted characteristic fiber auxiliary yarns; Step 2: Ply N pre-twisted characteristic fiber main yarns and pre-twisted characteristic fiber auxiliary yarns, bind them into a group of yarns, and then pass through a plying roller to enter a twisting device; Step 3: Twist the plied yarn and spray a certain sizing agent to bind the pre-twisted characteristic fiber auxiliary yarn and spirally interweave to wrap the pre-twisted characteristic fiber main yarn together; Step 4: passing the twisted yarn bundle through a short-cut device, cutting the pre-twisted characteristic fiber auxiliary yarn at the periphery of the twisted yarn at a fixed length, retaining the continuity of the pre-twisted characteristic fiber main yarn at the center of the twisted yarn bundle, and obtaining a fixed-length continuous fiber; Step 5: The fixed-length continuous fiber is rewound onto the fiber drum and stored.

2. A method for preparing a fixed-length continuous fiber, characterized in that: The following steps are involved: Step 1: For non-pre-twisted characteristic fibers, a single non-pre-twisted characteristic fiber yarn is subjected to yarn hanging, tensioning, and yarn guiding processes; Step 2: widen the single non-pre-twisted characteristic fiber yarn through a widening process, so that it is flattened and spread out to form a two-dimensional plane with a certain area; Step 3: The non-pre-twisted characteristic fiber yarn after widening is passed through a short-cut device, and the short-cut device cuts the non-pre-twisted characteristic fiber yarn at half length on both sides after widening, and only retains the fiber continuity in the middle area to obtain a fixed-length continuous fiber; Step 4: The fixed-length continuous fiber is rewound onto the fiber drum and stored.

3. The method for preparing a fixed-length continuous fiber according to claim 1, characterized in that: In step 1, N is greater than or equal to 3.

4. The method for preparing a fixed-length continuous fiber according to claim 1, characterized in that: The pre-twisted characteristic fibers in step 2 are quartz fibers, alumina fibers, and zirconia fibers.

5. The method for preparing a fixed-length continuous fiber according to claim 1, characterized in that: The twisting method in step 3 is a wrapping twisting method.

6. The method for preparing a fixed-length continuous fiber according to claim 1, characterized in that: The pre-twisted characteristic fiber auxiliary yarn in step 4 is the Z-direction fiber in the needle-punched preform.

7. The method for preparing a fixed-length continuous fiber according to claim 2, characterized in that: The non-pre-twisted fibers are carbon fibers.

8. The method for preparing a fixed-length continuous fiber according to claim 1 or 2, characterized in that: The short cutting device is a ring knife, a chopping knife or a raising loop.

9. The method for preparing a fixed-length continuous fiber according to claim 1 or 2, characterized in that: The short cutting device is a ring knife device, which comprises a ring knife (1), a bracket (2), a motor I (3), a motor II (4), a motor III (5), an active roller (6), a driven roller I (7), and a driven roller II (8). The ring knife (1) is mounted on the bracket (2), the motor I (3), the motor II (4), and the motor III (5) are fixed on the bracket (2), and the motor I (3), the motor II (4), and the motor III (5) are connected to the active roller (6), the driven roller I (7), and the driven roller II (8) respectively. 8), the active roller (6), the driven roller I (7) and the driven roller II (8) are rollers with grooves, which are located at the edge of the ring cutter (1) and can drive the ring cutter (1) to rotate, the ring cutter (1) comprises an inner opening (1-1) and an outer opening (1-2), the inner opening (1-1) passes through the ring cutter (1), the outer opening (1-2) is arranged at the surface of the ring cutter (1) where the inner opening (1-1) is located, and the diameter of the outer opening (1-2) is larger than the diameter of the inner opening (1-1).

10. The method for preparing a fixed-length continuous fiber according to claim 9, characterized in that: The short-cut device comprises two circular knife devices, which are paired together. The length of the fixed-length fibers in the fixed-length continuous fibers can be changed by adjusting the spacing between the two circular knife devices.

11. The method for preparing a fixed-length continuous fiber according to claim 10, characterized in that: When the two ring knife devices are paired together, the inner openings (1-1) of the two ring knives (1) are staggered to ensure that the two ring knives (1) can cut the two sides of the fiber respectively, and the staggered displacement distance is less than or equal to the radius of the inner opening (1) of the ring knife.

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