A composite material preform single-edge stitching method based on a rotating needle

Abstract

The application discloses a composite material preform single-edge sewing method based on a rotating needle, and comprises the following steps: forming a wire loop, passing through the wire loop, hooking back the wire loop, rotating needle feeding, releasing the wire loop and rotating needle resetting. Compared with the prior art, the application improves the stability of stitch formation, improves the interlayer performance of the preform layer, and the mechanism applied by the method is simple in structure and convenient to debug.

Description

Technical Field

[0001] This invention relates to the field of single-sided stitching technology for composite material preforms, and specifically to a single-sided stitching method for composite material preforms based on a rotating needle. Background Technology

[0002] Composite materials, due to their high specific strength, strong design flexibility, and corrosion resistance, have been widely used in aerospace and rail transportation fields. However, traditional prepreg layup processes for composite materials suffer from poor interlayer properties. To address these issues, three-dimensional woven composite materials, as a composite material with advanced structures, have come into the research field and have seen significant development.

[0003] Currently, three-dimensional stitching technology, as a three-dimensional weaving process for composite material preforms, mainly includes double-sided stitching and single-sided stitching. While double-sided stitching devices have a simple structure, they occupy a large space and cannot process preforms with large and complex spatial shapes. Single-sided stitching mechanisms are all located on one side of the preform and can stitch preforms with complex and large spatial shapes, but the single-sided stitching process involves complex movements, requires high precision in the mechanism's operation, and suffers from unstable stitch formation. Therefore, there is an urgent need to develop a new single-sided stitching process with stable stitch formation. Summary of the Invention

[0004] Purpose of the invention: To solve the above problems, the present invention provides a single-sided stitching method for composite material preforms based on rotating needles, which improves the stability of stitch formation and enhances the interlayer performance of the plywood preforms. At the same time, the mechanism used in this method has a simple structure and is easy to debug.

[0005] Technical solution: To achieve the above objectives, the single-sided stitching method for composite material preforms based on rotating needles according to the present invention includes the following steps:

[0006] S1. Forming a loop: The threading needle with the suture thread passes through the fabric at a preset angle to the fabric plane and moves downward. After the threading needle moves to the lower stop point, it returns along the same path. During the return process, the suture thread forms a loop, and at the same time, the hook needle passes through the fabric in a direction perpendicular to the fabric plane.

[0007] S2. Passing through the loop: The thread needle continues to retract along a predetermined angle with the fabric plane, while the hook needle continues to move downward and passes through the loop formed by the sewing thread in S1. After the hook needle moves to the lower stop point, it retracts along the same path.

[0008] S3. Thread loop: The lead needle continues to retract until it passes through the fabric, while the hook needle continues to retract into the fabric, during which the thread is hooked back by the hook needle;

[0009] S4. Needle feed: Both the lead needle and the hook needle continue to move along the direction in S3 to the top of the fabric. After both the lead needle and the hook needle have exited the fabric, the feed motion is completed, and the hook needle is rotated. After rotation, the tip of the hook needle enters the thread loop.

[0010] S5. Release the thread loop: After the feed motion in S4 is completed, the lead needle moves downward at a preset angle to the fabric plane and passes through the fabric, the hook needle moves downward perpendicular to the fabric plane and passes through the fabric, and the thread loop hooked back in S3 comes out of the hook needle opening, while the thread loop is locked by the hook needle.

[0011] S6. Needle Reset: After the thread needle and hook needle pass through the sewing material, rotate the hook needle and repeat S1 to S6 to complete the process cycle;

[0012] After multiple cycles, two parallel suture lines are obtained.

[0013] Furthermore, the needle is at a preset angle to the sewing material plane, the angle being 30 to 60 degrees.

[0014] Furthermore, the initial orientation of the hook needle is inward at the horizontal position of the sewing fabric, and the initial orientation of the guide needle is inward at the horizontal position of the sewing fabric.

[0015] Furthermore, the lower stop point of the needle described in S1 is the vertical distance between the needle tip and the bottom of the fabric, which is 15-25mm.

[0016] Furthermore, the lower stop point of the hook needle mentioned in S2 is the vertical distance between the needle tip and the bottom of the fabric, which is 15-25mm.

[0017] Furthermore, the feeding motion direction described in S4 is outward from the horizontal position of the sewing material, and the feeding distance is 5-15mm.

[0018] Furthermore, as described in S6, the hook needle and the guide needle rotate after passing through the fabric for 8-10 mm.

[0019] Furthermore, the hook needle rotates 180° in either a counter-clockwise or clockwise direction.

[0020] Furthermore, the suture is made of twisted or untwisted carbon fiber filaments.

[0021] Furthermore, the suturing speed of the suture is 200-400 stitches per minute.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant effects: by adjusting the orientation of the needle opening of the guide needle and the hook opening of the hook needle, the phenomenon of mis-hooking is reduced and the stability of the suture stitch formation is improved; by applying the guide needle and the hook needle to the sewing mechanism, the mechanism structure is simple and easy to adjust. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process of the present invention.

[0024] Figure 2 This is a schematic diagram illustrating the change in the position of the needle tip before and after the hook needle is rotated according to the present invention. Detailed Implementation

[0025] This invention discloses a method for single-sided stitching of composite material preforms based on a rotating needle. Please refer to [link / reference]. Figures 1 to 2 As shown below, the single-sided stitching method for composite material preforms based on rotating needles provided by the present invention will be further described in detail: The single-sided stitching method for composite material preforms based on rotating needles includes the following steps:

[0026] Step 1: Forming a Loop: The threading needle with the suture thread passes through the fabric at a preset angle and moves downwards. After reaching its lower stop point, the threading needle retracts along the same path, forming a loop during the retraction. Simultaneously, the hook needle passes through the fabric perpendicular to its plane. The preset angle between the threading needle and the fabric plane is 45 degrees; the initial orientation of both the hook needle and the threading needle is inwards from the horizontal position of the fabric; the lower stop point of the threading needle is the vertical distance between the needle tip and the bottom of the fabric, which is 20mm.

[0027] Step 2: Passing through the loop: The lead needle continues to retract at a 45-degree angle to the fabric plane, while the hook needle continues to move downwards and passes through the loop formed by the stitching in Step 1. The hook needle moves to its lower stop point and then retracts along the same path. The lower stop point of the hook needle is the vertical distance between the needle tip and the bottom of the fabric, which is 20mm.

[0028] Step 3: Hooking back the thread loop: The needle continues to retract until it passes through the fabric, while the hook needle continues to retract into the fabric. During this process, the thread is hooked back by the hook needle.

[0029] Step 4: Needle Feeding: Both the guide needle and the hook needle continue moving in the direction described in Step 3 until they are above the fabric. After both the guide needle and the hook needle have exited the fabric, the feeding motion is complete, and the hook needle is rotated. After rotation, the tip of the hook needle enters the thread loop. The feeding direction is outward from the horizontal position of the fabric, and the feeding distance is 10mm. The hook needle rotates 180° counterclockwise or clockwise, with the hook needle tip facing outward from the horizontal position of the fabric. The guide needle tip remains unchanged, reducing mis-hooking and improving the stability of the stitch formation.

[0030] Step 5: Release the loop: After the feed motion in step 4 is completed, the lead needle moves downward at a 45-degree angle to the fabric plane and passes through the fabric. The hook needle moves downward perpendicular to the fabric plane and passes through the fabric. Due to the obstruction of the fabric, the loop hooked back in step 3 comes out of the hook needle's opening, and at the same time, the loop is locked by the hook needle.

[0031] Step 6: Needle Reset: After the thread guide needle and hook needle have passed through the fabric by 10mm, rotate the hook needle and repeat steps 1 to 6 to complete the process cycle. The suture thread can be twisted or untwisted carbon fiber, and the sewing speed is 200-400 stitches / minute. After multiple cycles, two parallel suture stitches are obtained. This method improves the stability of the suture stitch formation, enhances the interlayer performance of the plywood prefabrication, and the mechanism used is simple and easy to debug.

Claims

1. A method for single-sided stitching of composite material preforms based on rotating needles, characterized in that, Includes the following steps: S1. Forming a loop: The thread-leading needle with the suture thread passes through the fabric at a preset angle to the fabric plane and moves downwards. After the thread-leading needle reaches its lower stop point, it retracts along the same path. During the retraction process, the suture thread forms a loop. At the same time, the hook needle passes through the fabric in a direction perpendicular to the fabric plane. The initial orientation of the hook needle's opening is inwards from the horizontal position of the fabric, and the initial orientation of the thread-leading needle's opening is inwards from the horizontal position of the fabric. S2. Passing through the loop: The thread needle continues to retract along a predetermined angle with the fabric plane, while the hook needle continues to move downward and passes through the loop formed by the sewing thread in S1. After the hook needle moves to the lower stop point, it retracts along the same path. S3. Thread loop: The lead needle continues to retract until it passes through the fabric, while the hook needle continues to retract into the fabric, during which the thread is hooked back by the hook needle; S4. Needle feed: Both the lead needle and the hook needle continue to move along the direction in S3 to the top of the fabric. After both the lead needle and the hook needle have exited the fabric, the feed motion is completed, and the hook needle is rotated. After rotation, the tip of the hook needle enters the thread loop. The feed motion direction is outward from the horizontal position of the fabric, and the feed distance is 5~15mm. S5. Release the thread loop: After the feed motion in S4 is completed, the lead needle moves downward at a preset angle to the fabric plane and passes through the fabric, the hook needle moves downward perpendicular to the fabric plane and passes through the fabric, and the thread loop hooked back in S3 comes out of the hook needle opening, while the thread loop is locked by the hook needle. S6. Needle Reset: After the thread needle and hook needle pass through the sewing material, rotate the hook needle and repeat S1 to S6 to complete the process cycle; the hook needle rotates 180° in either a counterclockwise or clockwise direction. After multiple cycles, two parallel suture lines are obtained.

2. The method for single-sided stitching of composite material preforms based on rotating needles according to claim 1, characterized in that, The guide needle is at a preset angle to the sewing material plane, with the angle being 30 to 60 degrees.

3. The method for single-sided stitching of composite material preforms based on rotating needles according to claim 1, characterized in that, The lower stop point of the needle mentioned in S1 is the vertical distance between the needle tip and the bottom of the fabric, which is 15~25mm.

4. The method for single-sided stitching of composite material preforms based on rotating needles according to claim 1, characterized in that, The lower stop point of the hook needle mentioned in S2 is the vertical distance between the needle tip and the bottom of the fabric, which is 15~25mm.

5. The method for single-sided stitching of composite material preforms based on rotating needles according to claim 1, characterized in that, The hook needle described in S6 rotates after passing through the fabric for 8-10mm.

6. The method for single-sided stitching of composite material preforms based on rotating needles according to claim 1, characterized in that, The suture is made of twisted or untwisted carbon fiber filament.

7. The method for single-sided stitching of composite material preforms based on rotating needles according to claim 6, characterized in that, The suturing speed of the suture is 200-400 stitches per minute.

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