Single-side stitching method for composite material preform based on rotating needle

Abstract

The invention discloses a single-side sewing method for a composite material preform based on a rotating needle. The single-side sewing method comprises the following steps of forming a thread ring, penetrating through the thread ring, hooking the thread ring back, feeding the rotating needle, releasing the thread ring and resetting the rotating needle. Compared with the prior art, the method has the advantages that the forming stability of the suture trace is improved, the interlayer performance of the laying preform is improved, and meanwhile, a mechanism applied to the method is simple in structure and convenient to debug.

Description

Technical Field

[0001] The invention relates to the technical field of single-side sewing of composite material preforms, and in particular to a single-side sewing method of composite material preforms based on a rotating needle. Background Art

[0002] Composite materials have been widely used in aerospace and rail transportation due to their high specific strength, strong designability, corrosion resistance and other characteristics. However, the traditional composite prepreg lamination process has the problem of poor interlayer performance of composite materials. To solve the above problems, three-dimensional woven composite materials, as a composite material with advanced structure, have entered the field of vision of scientific researchers and have made great progress.

[0003] At present, three-dimensional stitching technology, as a three-dimensional weaving process for composite material preforms, mainly includes double-sided stitching and single-sided stitching. Among them, the double-sided stitching device has a simple structure but occupies a large space and cannot process preforms with large and complex spatial shapes. The single-sided stitching mechanism is located on one side of the preform and can stitch preforms with complex large and complex spatial shapes. However, the single-sided stitching process is complicated and requires high actuation accuracy of the mechanism, and there is a problem of unstable stitch formation. Therefore, it is urgent 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-mentioned problems, the present invention provides a method for single-sided stitching of a composite material preform based on a rotating needle, which improves the stability of stitch formation and the interlayer performance of the laminated preform. At the same time, the mechanism structure used in this method is simple and easy to debug.

[0005] Technical solution: To achieve the above-mentioned purpose, the method for unilaterally stitching a composite material preform based on a rotating needle of the present invention comprises the following steps:

[0006] S1. Loop formation: The thread guide needle with the suture thread passes through the sewing material at a preset angle to the plane of the sewing material and moves downward. After the thread guide needle moves to the lower dead point of the thread guide needle, it retreats along the original path. During the retreat process, the suture thread forms a thread loop, and at the same time, the thread hook needle passes through the sewing material in a direction perpendicular to the plane of the sewing material;

[0007] S2. Passing through the thread loop: The thread guide needle continues to retreat in a direction at a preset angle to the plane of the sewing material, while the thread hook needle keeps moving downward and passes through the thread loop formed by the suture thread in S1, and the thread hook needle moves to the lower stop point of the thread hook needle and then retreats along the original path;

[0008] S3. Hooking back the thread loop: The thread guide needle continues to retreat until it passes through the sewing material, and the thread hooking needle continues to retreat to the sewing material. During the process, the sewing thread is hooked back by the thread hooking needle;

[0009] S4. Rotating needle feeding: the thread guide needle and the thread hook needle continue to move along the direction in S3 to the top of the sewing material, and the thread guide needle and the thread hook needle are both out of the sewing material. The feeding movement is completed, and the thread hook needle is rotated. After the rotation, the needle tip of the thread hook needle enters the thread loop;

[0010] S5. Release the thread loop: After completing the feeding movement in S4, the thread guide needle moves downward at a preset angle to the plane of the sewing material and passes through the sewing material, the thread hook needle moves downward in a direction perpendicular to the plane of the sewing material and passes through the sewing material, and the thread loop hooked back by the thread hook needle in S3 escapes from the needle hole of the thread hook needle, and the thread loop is locked by the thread hook needle;

[0011] S6. Needle rotation reset: After the thread guide needle and the thread hook needle pass through the sewing material, the thread hook needle is rotated, and S1 to S6 are repeated to complete the process step cycle;

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

[0013] Furthermore, the thread guide needle and the sewing material plane are at a preset angle of 30 to 60 degrees.

[0014] Furthermore, the initial orientation of the needle opening of the hook thread needle is inwards from the horizontal position of the sewing material, and the initial orientation of the needle opening of the lead thread needle is inwards from the horizontal position of the sewing material.

[0015] Furthermore, the lower dead point of the thread guide needle in S1 is the vertical distance point between the needle tip and the bottom of the sewing material, and the distance is 15 to 25 mm.

[0016] Furthermore, the lower dead point of the hook needle in S2 is the vertical distance point between the needle tip and the bottom of the sewing material, and the distance is 15 to 25 mm.

[0017] Furthermore, the feeding movement direction in S4 is from the horizontal position of the sewing material to the outside, and the feeding distance is 5 to 15 mm.

[0018] Furthermore, the thread hook needle and the thread guide needle in S6 rotate the thread hook needle after penetrating the sewing material by 8 to 10 mm.

[0019] Furthermore, the hook needle rotates 180 degrees counterclockwise or clockwise.

[0020] Furthermore, the suture thread is a twisted carbon fiber filament or an untwisted carbon fiber filament.

[0021] Furthermore, the suture thread has a suturing speed of 200 to 400 stitches per minute.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant effects: by adjusting the directions of the needle mouth of the thread guide needle and the hook mouth of the thread hook needle, the phenomenon of mis-hooking is reduced and the stability of suture stitch formation is improved; the thread guide needle and the thread hook needle are applied to the suture mechanism, the mechanism structure is simple and easy to debug. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0024] Figure 2 It is a schematic diagram of the change of the needle mouth position before and after the hook needle is turned. DETAILED DESCRIPTION

[0025] The present invention discloses a method for unilaterally sewing a composite material preform based on a rotating needle. Figure 1 to Figure 2 As shown, the composite material preform unilateral sewing method based on the rotating needle provided by the present invention is further described in detail below: The composite material preform unilateral sewing method based on the rotating needle comprises the following steps:

[0026] Step 1: Forming a loop: The thread guide needle with the suture thread passes through the sewing material at a preset angle to the plane of the sewing material and moves downward. The thread guide needle moves to the lower dead point of the thread guide needle and then retreats along the original path. During the retreat, the suture thread forms a thread loop, and the hook thread needle passes through the sewing material in a direction perpendicular to the plane of the sewing material. Among them, the thread guide needle is at a preset angle of 45 degrees to the plane of the sewing material; the initial direction of the hook thread needle mouth is inward from the horizontal position of the sewing material, and the initial direction of the thread guide needle mouth is inward from the horizontal position of the sewing material; the lower dead point of the thread guide needle is the vertical distance point between the needle tip and the bottom of the sewing material, and the distance is 20mm.

[0027] Step 2: Pass through the thread loop: The thread guide needle continues to retreat in a 45-degree direction to the plane of the sewing material, while the thread hook needle keeps moving downward and passes through the thread loop formed by the sewing thread in the first step. The thread hook needle moves to the lower stop point of the thread hook needle and then retreats along the original path. The lower stop point of the thread hook needle is the vertical distance point between the needle tip and the bottom of the sewing material, and the distance is 20mm.

[0028] Step 3: Hook back the thread loop: The guide needle continues to retreat until it passes through the sewing material, and at the same time, the hook needle continues to retreat to the sewing material. During the process, the thread is hooked back by the hook needle.

[0029] Step 4: Needle feeding: Both the thread guide needle and the thread hook needle continue to move in the direction of the third step to the top of the sewing material. After both the thread guide needle and the thread hook needle exit the sewing material, the feeding movement is completed, and the thread hook needle is rotated. After the rotation, the thread hook needle tip enters the thread loop. Among them, the feeding movement direction is from the horizontal position of the sewing material to the outside, and the feeding distance is 10mm; the thread hook needle rotates 180° in the counterclockwise direction or clockwise direction, and the needle mouth of the thread hook needle faces the horizontal position of the sewing material outward, and the direction of the thread guide needle needle mouth remains unchanged, which reduces the phenomenon of mis-hooking and improves the stability of the stitch formation.

[0030] Step 5: Release the thread loop: After completing the feeding movement in the fourth step, the lead needle moves downward at 45 degrees to the plane of the sewing material and passes through the sewing material, and the hook needle moves downward in a direction perpendicular to the plane of the sewing material and passes through the sewing material. Due to the obstruction of the sewing material, the thread loop hooked back in the third step slips out of the needle mouth of the hook needle, and the thread loop is locked by the hook needle.

[0031] Step 6: Needle reset: After the lead needle and the hook needle pass through the sewing material 10mm, the hook needle is rotated, and the first to sixth steps are repeated to complete the process step cycle. Among them, the suture thread is a twisted carbon fiber filament or an untwisted carbon fiber filament, and the suture speed is 200 to 400 needles / minute. After multiple cycles, two parallel suture traces are obtained. The above method improves the stability of the suture trace formation and the interlayer performance of the laminated preform. At the same time, the mechanism structure used in this method is simple and easy to debug.

Claims

1. A method for unilaterally sewing a composite material preform based on a rotating needle, characterized in that: The following steps are involved: S1. Loop formation: The thread guide needle with the suture thread passes through the sewing material at a preset angle to the plane of the sewing material and moves downward. After the thread guide needle moves to the lower dead point of the thread guide needle, it retreats along the original path. During the retreat process, the suture thread forms a thread loop, and at the same time, the thread hook needle passes through the sewing material in a direction perpendicular to the plane of the sewing material; S2. Passing through the thread loop: The thread guide needle continues to retreat in a direction at a preset angle to the plane of the sewing material, while the thread hook needle keeps moving downward and passes through the thread loop formed by the suture thread in S1, and the thread hook needle moves to the lower stop point of the thread hook needle and then retreats along the original path; S3. Hooking back the thread loop: The thread guide needle continues to retreat until it passes through the sewing material, and the thread hooking needle continues to retreat to the sewing material. During the process, the sewing thread is hooked back by the thread hooking needle; S4. Rotating needle feeding: the thread guide needle and the thread hook needle continue to move along the direction in S3 to the top of the sewing material, and the thread guide needle and the thread hook needle are both out of the sewing material. The feeding movement is completed, and the thread hook needle is rotated. After the rotation, the needle tip of the thread hook needle enters the thread loop; S5. Release the thread loop: After completing the feeding movement in S4, the thread guide needle moves downward at a preset angle to the plane of the sewing material and passes through the sewing material, the thread hook needle moves downward in a direction perpendicular to the plane of the sewing material and passes through the sewing material, and the thread loop hooked back by the thread hook needle in S3 escapes from the needle hole of the thread hook needle, and the thread loop is locked by the thread hook needle; S6. Needle rotation reset: After the thread guide needle and the thread hook needle pass through the sewing material, the thread hook needle is rotated, and S1 to S6 are repeated to complete the process step cycle; After multiple cycles, two parallel suture stitches are obtained.

2. The method for unilaterally sewing a composite material preform based on a rotating needle according to claim 1, characterized in that: The thread guide needle and the sewing material plane form a preset angle, which is 30 to 60 degrees.

3. The method for unilaterally sewing a composite material preform based on a rotating needle according to claim 1, characterized in that: The initial orientation of the needle opening of the hook thread needle is inward from the horizontal position of the sewing material, and the initial orientation of the needle opening of the lead thread needle is inward from the horizontal position of the sewing material.

4. The method for unilaterally sewing a composite material preform based on a rotating needle according to claim 1, characterized in that: The lower dead point of the thread guide needle in S1 is the vertical distance point between the needle tip and the bottom of the sewing material, and the distance is 15 to 25 mm.

5. The method for unilaterally sewing a composite material preform based on a rotating needle according to claim 1, characterized in that: The lower dead point of the hook thread needle in S2 is the vertical distance point between the needle tip and the bottom of the sewing material, and the distance is 15 to 25 mm.

6. The method for unilaterally sewing a composite material preform based on a rotating needle according to claim 1, characterized in that: The feeding movement direction in S4 is from the horizontal position of the sewing material to the outside, and the feeding distance is 5 to 15 mm.

7. The method for unilaterally sewing a composite material preform based on a rotating needle according to claim 1, characterized in that: The thread hooking needle and the thread guide needle in S6 rotate the thread hooking needle after passing through the sewing material for 8 to 10 mm.

8. The method for single-side stitching of composite material preforms based on rotating needle according to claim 1, characterized in that: The hook needle rotates 180° in a counterclockwise direction or a clockwise direction.

9. The method for unilaterally sewing a composite material preform based on a rotating needle according to claim 1, characterized in that: The suture is a twisted carbon fiber filament or an untwisted carbon fiber filament.

10. The method for single-side stitching of composite material preforms based on rotating needle according to claim 9, characterized in that: The suture speed of the suture thread is 200 to 400 stitches per minute.

Images