Accurate composite material sewing method

Abstract

The invention discloses an accurate composite material sewing method, which relates to the technical field of material sewing and comprises the following steps: prefabricating a plurality of reference holes outside a margin line of a forming tool, and preassembling positioning pins in the reference holes; laying the sewn parts on the forming tool, and enabling the positioning pins to penetrate through the sewn parts to form datum holes with the corresponding number; projecting and marking suture positions; on the basis of the reference hole, transferring the suturing part to a suturing platform, fixing the suturing part through a positioning device, and suturing the suturing part according to the suturing position; transferring the sewing part to the forming tool, and fixing the sewing part by using the positioning pin based on the reference hole; and curing and sewing the part and forming. The consistency of the sewing positioning reference of the sewing part on the forming tool and the sewing platform is guaranteed, the sewing precision is improved, the technical problem of positioning deviation of the sewing position caused by repeated transfer between the forming tool and the sewing platform in the sewing process is solved, and the product quality is effectively improved.

Description

Technical Field

[0001] This application relates to the field of material stitching technology, specifically to a method for precise stitching of composite materials. Background Technology

[0002] Composite materials are novel materials created by combining two or more materials with different properties through physical or chemical methods. Their overall performance is superior to that of single-component materials.

[0003] The traditional stitching process for composite materials is as follows: First, the stitching parts are laid out on the part forming fixture. Then, the laid-out stitching parts are transferred from the forming fixture to the stitching platform for stitching. After stitching is completed, the stitching parts are returned from the stitching platform to the forming fixture for curing and molding.

[0004] Normally, the position of the stitches is determined by laser projection during the molding process. However, during the sewing process, the stitches need to be repeatedly transferred between the molding fixture and the sewing platform. This can easily lead to a deviation between the position of the stitches when the stitches are placed on the molding fixture and the position of the stitches when the stitches are placed on the sewing platform. As a result, the position of the stitches on the stitches is inaccurate, inconsistent with the part's digital model, does not meet the requirements, and cannot be delivered. Summary of the Invention

[0005] The main objective of this application is to provide a precise stitching method for composite materials, which aims to solve the technical problem that traditional stitching operations for composite materials are prone to deviations in suture position due to repeated transfer of the stitched parts between the molding fixture and the stitching platform, thus affecting the stitching quality.

[0006] The technical solution adopted in this application is as follows: A method for precise stitching of composite materials includes the following steps: Several reference holes are pre-drilled outside the allowance line of the forming tooling, and positioning pins are pre-installed in the reference holes. The stitched parts are stacked on the forming tooling, and the positioning pins pass through the stitched parts to form a corresponding number of reference holes; Project and mark the suture positions; Based on the reference hole, the suture part is transferred to the suture platform and fixed by the positioning device, and the suture part is sutured according to the suture position; Transfer the stitched part to the forming fixture and secure it using the locating pin based on the reference hole; Curing and stitching parts into shape.

[0007] Furthermore, the reference holes are located at both ends of the stitched part along its length and are symmetrically distributed.

[0008] Further, the projection and marking of suture positions includes: The stitching position is projected using laser projection based on the part's digital model; Holes are punched at the edges of the material using mechanical means or lasers to mark the seam locations.

[0009] Furthermore, the suturing platform includes a platform body and a fixing beam, the fixing beam being vertically disposed on the platform body and located at both ends of the length direction of the suturing part.

[0010] Furthermore, the positioning device includes: A positioning plate, wherein the positioning plate is provided with first positioning holes at intervals equal to the number of reference holes, and the distance between the first positioning holes is the same as the distance between the reference holes; A pressure plate, wherein the pressure plate is provided with second positioning holes at intervals equal to the number of reference holes, and the distance between the second positioning holes is the same as the distance between the reference holes; A fastener is fixedly connected between the positioning plate and the fixing beam; The stitching part is located between the positioning plate and the pressure plate, and the reference hole, the first positioning hole and the second positioning hole correspond one-to-one and are coaxial. The positioning plate, the stitching part and the pressure plate are fixed by positioning bolts passing through the second positioning hole, the first positioning hole and the reference hole from top to bottom and positioning nuts.

[0011] Furthermore, the fastener includes an L-shaped corner piece, the vertical section of which is connected to the fixing beam, and the horizontal section of which is connected to the positioning plate.

[0012] Furthermore, the horizontal section of the L-shaped corner piece is connected to the positioning plate by connecting bolts and fixed by connecting nuts.

[0013] Furthermore, the platform body is provided with multiple mounting plates, and the mounting plates are provided with mounting holes for connecting the positioning bolts and the connecting bolts.

[0014] Furthermore, the vertical section of the L-shaped corner piece is bonded and fixed to the fixing beam using metal adhesive.

[0015] Furthermore, the fasteners are located at both ends of the stitched part along its length and are arranged symmetrically.

[0016] Compared with the prior art, the present application proposes a method for precise stitching of composite materials, comprising the following steps: pre-forming several reference holes outside the allowance line of a molding fixture, and pre-installing positioning pins in the reference holes; stacking the stitching parts on the molding fixture, with the positioning pins penetrating the stitching parts to form a corresponding number of reference holes; projecting and marking the suture positions; based on the reference holes, transferring the stitching parts to a stitching platform and fixing them with a positioning device, and stitching the stitching parts according to the suture positions; transferring the stitching parts to the molding fixture, and fixing them with the positioning pins based on the reference holes; and curing the stitching parts. The significant beneficial effects of this method are: First, the precise stitching method for composite materials proposed in this application involves laying out positioning holes on the stitched parts and using these positioning holes for positioning on both the part forming fixture and the stitching machine. This ensures the consistency of the positioning reference and avoids the technical problem of positioning deviation of the stitch line caused by repeated transfer between the forming fixture and the stitching platform during the stitching process, thus effectively improving the product forming quality.

[0017] Second: The composite material precision sewing method proposed in this application sets positioning holes on the part forming fixture, lays the positioning holes on the part, and improves the existing sewing equipment by adding a positioning device to the sewing equipment. Then, based on the positioning holes, the sewing part is positioned on the newly added positioning device of the sewing equipment, which effectively ensures the consistency of the sewing position and solves the problem of inconsistent positioning reference caused by the change of position of the sewing part (from the forming fixture to the sewing machine, and then back to the forming fixture from the sewing machine).

[0018] Third: The composite material precision sewing method proposed in this application improves the sewing equipment by adding a positioning device (without modifying or damaging the sewing equipment) to achieve precise positioning of the sewn parts, thereby solving the problem that the original sewing equipment does not have a positioning function, and greatly improving the accuracy of the sewing position and sewing efficiency. Attached Figure Description

[0019] Figure 1 A schematic flowchart illustrating the precise stitching method for composite materials provided in this application embodiment; Figure 2 A schematic diagram of the forming tooling used for sewing parts; Figure 3 A schematic diagram showing the state of stitched parts when they are laid up on the forming tooling; Figure 4 A schematic diagram of the structure after the stitched parts have been stacked. Figure 5 This is a schematic diagram of the suture platform and positioning device.

[0020] Explanation of the labels in the attached drawings: 1-Forming fixture, 2-Reference hole, 3-Part allowance line, 4-Tooling allowance line, 5-Sewn part, 6-Positioning pin, 7-Reference hole, 8-Fixing beam, 9-Metal adhesive, 10-L-shaped corner piece, 11-Connecting bolt, 12-Connecting nut, 13-Pressure plate, 14-Positioning bolt, 15-Positioning nut, 16-Positioning plate, 17-Platform body, 18-First positioning hole, 19-Second positioning hole. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0023] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0024] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0025] As is well known in the art, in the traditional composite material stitching process, the stitching position is usually determined by laser projection on the molding fixture to project the stitch line, and then marking the stitch line position on the stitched part. However, when the stitched part is transported to the stitching platform, the stitching plane is a rolling surface, not a fixed one. During stitching, the stitched part can only be fixed by clamping tools on the edge fixing beam of the stitching platform. These clamping tools can only clamp and fix the stitched part around its perimeter and cannot play a role in positioning the stitched part. Therefore, it is difficult for the position of the stitched part on the stitching platform to be consistent with its position on the molding fixture, resulting in deviations when stitching according to the projected stitch line position. Furthermore, when the stitched part is returned to the molding fixture after stitching, it is usually positioned on the molding fixture by laser projection of the shape of the stitched part. However, during the stitching process, the stitched part undergoes a certain deformation due to the stitching force, causing the shape of the stitched part to change after stitching. It is difficult to accurately position it on the molding fixture, and the stitch line position changes again. As a result, the stitch line position on the stitched part is incorrect, inconsistent with the part's digital model, does not meet the requirements, and cannot be delivered.

[0026] To solve the above technical problems, refer to the appendix. Figure 1 This application provides a method for precise stitching of composite materials, including the following steps: S1: Pre-drill several reference holes outside the allowance line of the forming tooling, and pre-install positioning pins in the reference holes; S2: The stitched parts are laid on the forming fixture, and the positioning pins pass through the stitched parts to form a corresponding number of reference holes; S3: Project and mark the suture positions; S4: Based on the reference hole, the suture part is transferred to the suture platform and fixed by the positioning device, and the suture part is sutured according to the suture position; S5: Transfer the stitched part to the forming fixture and fix it using the positioning pin based on the reference hole; S6: Curing and stitching of parts.

[0027] In this embodiment, the following beneficial effects can be achieved: First, by using positioning holes to be stacked on the sewn parts, and using these positioning holes for positioning on both the part forming fixture and the sewing machine, the consistency of the positioning reference is ensured. This avoids the technical problem of positioning deviation of the sewing thread caused by repeated transfer between the forming fixture and the sewing platform during the sewing process, and effectively improves the product forming quality.

[0028] Second: Positioning holes are set on the part forming fixture, and the positioning holes are laid on the part. At the same time, the existing sewing equipment is improved by adding a positioning device to the sewing equipment. Then, the sewing part is positioned on the newly added positioning device of the sewing equipment based on the positioning holes, which effectively ensures the consistency of the sewing position and solves the problem of inconsistent positioning reference caused by the change of the position of the sewing part (from the forming fixture to the sewing machine, and then back to the forming fixture from the sewing machine).

[0029] Third: By improving the suturing equipment and adding a positioning device (without modifying or damaging the suturing equipment), the precise positioning of the suturing parts is achieved, thus solving the problem that the original suturing equipment did not have a positioning function, and greatly improving the accuracy of the suturing position and the suturing efficiency.

[0030] To further understand each step of the precise stitching method for composite materials provided in the embodiments of this application, a specific example of stitching a composite material part will be used for detailed explanation: For step S1, as Figure 2 As shown, four reference holes 2 with a diameter of 6 mm are manufactured outside the tooling allowance line 4 of the forming tooling 1 for stitching composite material parts. The four reference holes 2 are distributed at both ends along the length of the stitched part, with two reference holes 2 at each end, maintaining a symmetrical positional relationship. The reference holes 2 are 5 mm deep, and each reference hole 2 is equipped with a positioning pin 6. Inside the tooling allowance line 4, there is a part allowance line 3. The part allowance line 3 is a key process line marked by the scribing process before the part is processed, used to clarify the processing boundary and the material removal range.

[0031] In step S1, reference holes 2 are pre-made on the forming fixture, and positioning pins are set in the reference holes 2 to provide a reference for the positioning holes to be formed after the subsequent sewing parts 5 are laid on the forming fixture, thereby providing a positioning reference for the positional changes of the subsequent sewing parts 5 on the forming fixture and sewing platform.

[0032] In step S1, since the sewn parts are subjected to sewing force during the sewing process, the deformation in the length direction is relatively large. Therefore, by distributing the four reference holes at both ends of the length direction of the parts, with two at each end, it helps to reduce the amount of deformation during the sewing process.

[0033] For step S2, as Figure 3 As shown, when the stitched parts 5 are laid on the molding fixture 1, the positioning pin 6 is inserted into the reference hole 2 on the molding fixture, and each layer of composite material of the stitched parts 5 passes through the positioning pin 6.

[0034] In step S2, by passing the stitching parts layer by layer through the positioning pins 6 on the forming fixture 1, reference holes are formed on the stitching parts 6, which facilitates the positioning of the stitching parts 6 when they are transferred between the forming fixture and the stitching platform.

[0035] For step S3, the stitch position is projected onto the surface of the stitched part using laser projection based on the part's digital model. Then, holes are punched at the edge of the material using mechanical means or a laser to mark the stitch position.

[0036] In step S2, the accuracy of the stitch position is ensured by projecting the stitch position based on the digital model of the part. At the same time, permanent stitch marks are formed by drilling holes on the edge of the material using machinery or laser. This allows the stitch marks to be clearly seen when the sewn part is transferred to the sewing platform for sewing, which helps to ensure the accuracy of the sewing.

[0037] For step S4, as Figure 4 As shown, after the stitching part 5 is laid up, the stitching part 5 is removed from the forming device 1. Four reference holes 7 are formed on the stitching part 5. Based on the reference holes 7, the stitching part is transferred to the stitching platform and fixed by the positioning device. The stitching part is then stitched according to the suture position.

[0038] Among them, such as Figure 5 As shown, the suturing platform includes a platform body 17 and a fixed beam 8. The fixed beam 8 is vertically arranged on the platform body 17 and is located at both ends of the length direction of the suturing part 5.

[0039] Meanwhile, the positioning device includes a positioning plate 16, a pressure plate 13, and a fixing component. The positioning plate 16 has the same number of first positioning holes 18 as the reference holes 7. The distance between the first positioning holes 18 is the same as the distance between the reference holes 2 on the forming fixture 1. The pressure plate 13 has the same number of second positioning holes 19 as the reference holes 7. The distance between the second positioning holes 19 is the same as the distance between the reference holes 2 on the forming fixture 1. The first positioning holes 18 and the second positioning holes 19 are both through holes with a diameter of 6mm. During sewing, the sewing part 5 is placed between the positioning plate 16 and the pressure plate 13, with the positioning plate 16 below and the pressure plate 13 above. The first positioning holes 18, the second positioning holes 19, and the reference holes 7 are coaxially aligned. Then, the positioning screws 14 pass through the first positioning holes 18, the second positioning holes 19, and the reference holes 7 from top to bottom, connecting the positioning device and the sewing part in series. Finally, the positioning nuts 15 are used to lock and fix it, thereby ensuring that the sewing part has the same positioning reference on the forming fixture and on the sewing platform.

[0040] Continue as Figure 5As shown, the fasteners are located at both ends of the length of the sewn part and are symmetrically arranged. The fasteners include L-shaped corner pieces 10. The vertical section of the L-shaped corner piece 10 is bonded and fixed to the fixing beam 8 by metal adhesive 9. The horizontal section of the L-shaped corner piece 10 is connected to the positioning plate 16 by connecting bolts 11 and fixed by connecting nuts 12.

[0041] Meanwhile, multiple mounting plates are provided on the platform body 17. The mounting plates are provided with mounting holes for connecting the positioning bolts 14 and the connecting bolts 11, so that the positioning device can be installed on the sewing platform.

[0042] In step S4, by adding a positioning device without changing the existing structure of the sewing platform, the sewing parts are accurately positioned and installed on the sewing platform, which effectively ensures the consistency of the sewing position and solves the problem of inconsistent positioning reference caused by the change of the position of the sewing parts (from the forming fixture to the sewing machine, and then back to the forming fixture from the sewing machine). At the same time, the addition of the positioning device (without modifying or damaging the sewing equipment) enables precise positioning of the sewing parts, thereby solving the problem that the original sewing equipment does not have a positioning function, and greatly improving the accuracy of the sewing position and the sewing efficiency.

[0043] It should be noted that in the above embodiments, the metal adhesive 9 includes epoxy resin AB glue, acrylic structural adhesive, polyurethane adhesive, etc., and epoxy resin AB glue is the best choice in this embodiment.

[0044] For step S5, when the sewing is completed and the sewn part is removed from the sewing platform and returned to the forming fixture, the four reference holes on the sewn part are aligned with the four reference holes on the forming fixture, and then fixed with positioning pins, so that the sewn part is accurately returned to the forming fixture.

[0045] For step S5, the curing and molding of the composite material after stitching mainly involves a cross-linking reaction of the resin matrix through heat, pressure, or chemical reaction to form a stable three-dimensional network structure, thereby firmly bonding the reinforcing fibers and sutures. Curing and molding typically includes the following methods: Room temperature and pressure curing: Suitable for room temperature curing resin systems (such as polyester, epoxy, etc.), curing is completed through natural exothermic heating, which is low in cost but has a long cycle time; Pressure-heat curing: Using an autoclave or molding process, the resin cross-linking reaction is accelerated under high temperature (80–180°C) and pressure conditions, improving the mechanical properties of the laminate; Vacuum-assisted molding: Air bubbles are removed and uniform pressure is applied through a vacuum bag, combined with heat curing to reduce porosity and increase fiber volume fraction; UV curing: This method uses UV-curable resins, which undergo a polymerization reaction initiated by light. It has a fast curing speed but is only suitable for light-transmitting materials.

[0046] In this embodiment, heating and pressure curing are mainly used, and the main curing process includes: Increase the temperature according to the curing curve (e.g., 2°C / min to 180°C), avoiding internal stress, and simultaneously apply pressure (6 bar or 70–300 psi) to compact the fibers and suppress porosity. Maintain 180°C ± 5°C and pressure until the resin is fully cross-linked (usually 1–4 hours). During the cooling phase, maintain pressure to prevent deformation (cooling rate ≤ 1°C / min). After releasing the pressure, remove the vacuum bag, take out the cured part, and perform non-destructive testing (ultrasonic / X-ray).

[0047] In summary, the embodiments of this application provide a method for precise stitching of composite materials. It proposes to manufacture a reference hole on a molding fixture, transfer the reference hole to the stitching part to form a reference hole through a positioning pin, and set a positioning device on the stitching platform, and set a positioning hole at the corresponding position of the positioning device. By using the reference hole on the stitching part as a reference, the consistency of the stitching positioning reference is ensured, and the stitching accuracy is improved.

[0048] Furthermore, this application provides a method for precise stitching of composite materials. By improving existing stitching equipment, without changing the structure of the existing stitching equipment, a stitching positioning device is added to the stitching equipment to achieve rapid and precise positioning of the stitched parts on the stitching equipment, thereby improving the stitching accuracy and efficiency. Meanwhile, this application provides a method for precise stitching of composite materials. During the stitching process, the same positioning reference is set on the forming fixture and the stitching equipment. Even if the position of the stitched parts changes (from the forming fixture to the stitching machine, and then back to the forming fixture from the stitching machine), the positioning reference used is consistent, which effectively ensures the uniformity of the forming position and the stitching position of the stitched parts and the accuracy of the stitching position.

[0049] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method of precision stitching of composite materials, characterized in that, The method comprises the following steps: preparing a plurality of reference holes outside the excess line of a forming tool, and pre-installing positioning pins in the reference holes; laying up a stitched part in the forming tool, and forming a corresponding number of reference holes by penetrating the stitched part with the positioning pins; projecting and marking the suture position; transferring the stitched part to a stitching platform based on the reference holes, fixing by a positioning device, and stitching the stitched part according to the suture position; transferring the stitched part to the forming tool, and fixing based on the reference holes using the positioning pins; solidifying the stitched part.

2. The composite material precision stitching method of claim 1, wherein, The reference holes are located at both ends of the length direction of the stitched part and are symmetrically distributed.

3. The composite material precision stitching method of claim 1, wherein, The projecting and marking the suture position comprises: projecting the suture position based on a part model using a laser; punching holes at the edge of the material as the suture position using a machine or a laser.

4. The composite material precision stitching method of claim 1, wherein, The stitching platform comprises a platform body and a fixing beam, the fixing beam is vertically arranged on the platform body, and the fixing beam is located at both ends of the length direction of the stitched part.

5. The composite material precision stitching method of claim 4, wherein, The positioning device comprises: a positioning plate, a plurality of first positioning holes consistent with the number of the reference holes are arranged on the positioning plate at intervals, and the distance between the first positioning holes is the same as the distance between the reference holes; a pressing plate, a plurality of second positioning holes consistent with the number of the reference holes are arranged on the pressing plate at intervals, and the distance between the second positioning holes is the same as the distance between the reference holes; a fixing member, the fixing member is fixedly connected between the positioning plate and the fixing beam; wherein the stitched part is located between the positioning plate and the pressing plate, the reference holes, the first positioning holes and the second positioning holes are one-to-one corresponding and coaxial, and the positioning plate, the stitched part and the pressing plate are sequentially penetrated by positioning bolts from top to bottom through the second positioning holes, the first positioning holes and the reference holes and fixed by positioning nuts.

6. The composite material precision stitching method of claim 5, wherein, The fixing member comprises an L-shaped corner piece, the vertical segment of the L-shaped corner piece is connected with the fixing beam, and the horizontal segment of the L-shaped corner piece is connected with the positioning plate.

7. The composite material precision stitching method of claim 6, wherein, The horizontal segment of the L-shaped corner piece is connected with the positioning plate by a connecting bolt and fixed by a connecting nut.

8. The composite material precision stitching method of claim 7, wherein, A plurality of mounting plates are arranged on the platform body, and the mounting plates are provided with mounting holes for connecting the positioning bolts and the connecting bolts.

9. The composite material precision stitching method of claim 6, wherein, The vertical segment of the L-shaped corner piece is adhesively fixed with the fixing beam by a metal adhesive.

10. The composite material precision stitching method of claim 5, wherein, The fixing member is located at both ends of the length direction of the stitched part and is symmetrically arranged.

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