A secondary dipping method for composite wire suitable for additive manufacturing

Abstract

The application provides a secondary impregnation method for composite filament suitable for additive manufacturing, which comprises the following steps: firstly, performing fiber spreading operation on the fiber through a fiber spreading assembly; then, spraying a thermoplastic sizing layer on the surface of the fiber through a thermoplastic sizing layer spraying assembly during the fiber spreading process; and finally, performing impregnation treatment; and the fiber spreading assembly and the thermoplastic sizing layer spraying assembly are both installed on a rack. The application has the beneficial effect that: after the thermoplastic sizing layer is sprayed on the surface of the fiber during the fiber spreading process, the conventional impregnation treatment is performed, so that the impregnation degree of the continuous fiber reinforced composite filament is high, and the internal defects of the formed part are reduced; the thermoplastic sizing layer spraying assembly and the fiber spreading assembly are combined, so that the uniformity of the thermoplastic sizing layer on the surface of the fiber is effectively ensured, and the effect of the subsequent conventional impregnation treatment is ensured.

Description

Technical Field

[0001] This invention relates to the field of filament technology, and more specifically to a method for secondary impregnation of composite filaments suitable for additive manufacturing. Background Technology

[0002] Additive manufacturing of composite components is a future development trend. Fiber-reinforced composites are formed by combining reinforcing fibers, such as glass fiber, carbon fiber, and aramid fiber, with a matrix material through processes like winding, molding, or pultrusion. Based on the reinforcing materials, common fiber-reinforced composites are classified into glass fiber reinforced composites, carbon fiber reinforced composites, and aramid fiber reinforced composites. Currently, impregnation of fiber-reinforced composites still has shortcomings, and continuous fiber additive manufacturing technology needs further improvement. Summary of the Invention

[0003] To address the aforementioned problems, this invention discloses a secondary impregnation method for composite filaments suitable for additive manufacturing, which effectively solves the problem of insufficient impregnation during the impregnation process and improves the bonding between the resin and the fiber surface.

[0004] The specific plan is as follows:

[0005] A method for secondary impregnation of composite filaments suitable for additive manufacturing is characterized in that: firstly, the fibers are spread by a fiber spreading assembly, and during the fiber spreading process, a thermoplastic sizing layer is sprayed onto the surface of the fibers by a thermoplastic sizing layer spraying assembly, and then impregnation is performed. Both the fiber spreading assembly and the thermoplastic sizing layer spraying assembly are mounted on a frame.

[0006] As a further improvement of the present invention, the frame includes an upper frame and a lower frame arranged vertically. Both the upper frame and the lower frame are horizontally arranged rectangular plate structures. Vertical support columns are respectively provided at the four corners between the two. The upper and lower ends of the support columns are fixedly connected to the upper frame and the lower frame, respectively.

[0007] As a further improvement of the present invention, the fiber spreading assembly includes two fiber spreading devices symmetrically arranged front and rear. Each fiber spreading device includes two support assemblies arranged vertically. Each support assembly includes a horizontally arranged support rod. A strip-shaped groove is formed at the top of each support rod, and symmetrically detachable support limiting blocks are provided at both ends. A sliding block at the end of the strip-shaped groove is fitted and can slide along it. A mounting seat is detachably mounted on the top of the sliding block. A longitudinally arranged fiber spreading roller is provided between the two corresponding mounting seats, and the mounting seat is fitted and mounted on the end of the fiber spreading roller. The support rod is provided with a horizontally arranged limiting rod above it. The bottom of the upper support rod is provided with a horizontally arranged slide rail, and the top of the lower limiting rod is provided with a slide rail. A fixed block is provided in the middle of the slide rail, and sliding blocks that can slide left and right are provided on both sides. The upper and lower sliding blocks on the sides are hinged to the upper and lower fixed blocks in the middle by an X-shaped connecting rod. A trolley is installed at the intersection of the X-shaped connecting rod. A horizontally arranged guide rail is provided between the upper and lower fiber spreading devices. The trolley can slide left and right on the guide rail. The two ends of the guide rail are fixedly connected to the support columns on both sides respectively.

[0008] As a further improvement of the present invention, the cross section of the strip groove is an inverted T-shape, the lower part of the shaft end slider is an inverted T-shaped block adapted to the strip groove, and the upper part is a rectangular plate. The four apex corners of the rectangular plate are respectively threadedly connected and fixed to the positioning screw holes on the front and rear sides of the strip groove by bolts. The positioning screw holes on the front and rear sides of the strip groove are evenly distributed from left to right.

[0009] As a further improvement of the present invention, the two ends of the limiting rod are fixed to the supporting limiting blocks at both ends of the supporting rod by bolts, and a plurality of pressure blocks are placed on its bottom surface, which are the same number as the mounting base and corresponding in position. The pressure blocks are pressed onto the mounting base, and their top surfaces abut against the bottom surfaces of the limiting rod.

[0010] As a further improvement of the present invention, sliding sleeves that can slide along the guide rail are also installed on both sides of the guide rail, and the sliding sleeves are hinged to the upper and lower sliding blocks on the side by two rocker arms respectively.

[0011] As a further improvement of the present invention, a guide sleeve is provided on the outer side of the support limiting block, and a guide rod is passed through the upper and lower guide sleeves. The upper and lower ends of the guide rod are respectively fixedly connected to the upper frame and the lower frame.

[0012] As a further improvement of the present invention, the thermoplastic sizing layer spraying assembly includes spraying devices symmetrically arranged on the left and right sides of the fiber spreading assembly. The spraying device includes two first spraying heads symmetrically arranged vertically. The two first spraying heads are respectively installed on the bottom surface of the upper frame and the top surface of the lower frame. Horizontally arranged support plates are installed on the outer sides of the two corresponding support columns. Second spraying heads are respectively installed on the top and bottom surfaces of the support plates.

[0013] As a further improvement of the present invention, the upper and lower first spray heads are respectively installed on the bottom surface of the upper frame and the top surface of the lower frame via lifting cylinders, and the upper and lower second spray heads are respectively installed on the top and bottom surfaces of the support plate via lifting cylinders.

[0014] The beneficial effects of this invention are as follows: during the fiber spreading process, a thermoplastic sizing layer is sprayed onto the fiber surface before conventional impregnation treatment, resulting in a high degree of impregnation of the continuous fiber reinforced composite filaments and a reduction in internal defects of the formed parts; the combination of thermoplastic sizing layer spraying components and fiber spreading components effectively ensures the uniformity of the thermoplastic sizing layer on the fiber surface, guaranteeing the effect of subsequent conventional impregnation treatment. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention.

[0016] Figure 2 for Figure 1 Enlarged view of the fixed block section.

[0017] Figure 3 This is a schematic diagram of the shaft-end slider in this invention.

[0018] List of reference numerals in the attached diagram:

[0019] 1-Fiber, 2-Upper frame, 3-Lower frame, 4-Support column, 5-Support rod, 6-Strip groove, 7-Support limiting block, 8-Shaft end slider, 9-Mounting seat, 10-Fiber spreading roller, 11-Limiting rod, 12-Slide rail, 13-Fixing block, 14-Sliding block, 15-Moving trolley, 16-Guide rail, 17-Pressure block, 18-Sliding sleeve, 19-Guide sleeve, 20-Guide rod, 21-First spray head, 22-Support plate, 23-Second spray head, 24-Lifting cylinder. Implementation

[0020] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0021] As shown in the figure, a method for secondary impregnation of composite filament suitable for additive manufacturing is described. First, the fiber 1 is spread by a fiber spreading assembly. During the fiber spreading process, a thermoplastic sizing layer is sprayed onto the surface of the fiber 1 by a thermoplastic sizing layer spraying assembly. Then, an impregnation treatment is performed. Both the fiber spreading assembly and the thermoplastic sizing layer spraying assembly are mounted on a frame.

[0022] In this embodiment, the frame includes an upper frame 2 and a lower frame 3 arranged vertically. Both the upper frame 2 and the lower frame 3 are horizontally arranged rectangular plate structures. Vertical support columns 4 are respectively provided at the four corners between them. The upper and lower ends of the support columns 4 are fixedly connected to the upper frame 2 and the lower frame 3, respectively.

[0023] In this embodiment, the fiber spreading assembly includes two fiber spreading devices symmetrically arranged front and rear. Each fiber spreading device includes two support assemblies arranged vertically. Each support assembly includes a horizontally arranged support rod 5. The top of the support rod 5 has a horizontally oriented strip groove 6, and the left and right ends are symmetrically and detachably provided with support limiting blocks 7. A shaft end slider 8 that can slide along the strip groove is fitted in place. The top of the shaft end slider 8 is detachably fitted with a mounting seat 9. A longitudinally arranged fiber spreading roller 10 is provided between the two corresponding mounting seats 9, and the mounting seat 9 is fitted to the end of the fiber spreading roller 10. Above the support rod 5 is a... A horizontally arranged limiting rod 11 has a horizontally arranged slide rail 12 at the bottom of the upper support rod 5 and a slide rail 12 at the top of the lower limiting rod 11. A fixed block 13 is provided in the middle of the slide rail 12, and sliding blocks 14 that can slide left and right along it are provided on both sides. The upper and lower sliding blocks 14 on the sides are hinged to the upper and lower fixed blocks 13 in the middle through an X-shaped connecting rod. A moving trolley 15 is installed at the intersection of the X-shaped connecting rod. A horizontally arranged guide rail 16 is provided between the upper and lower fiber spreading devices. The moving trolley 15 can slide left and right on the guide rail 16. The two ends of the guide rail 16 are fixedly connected to the support columns 4 on both sides respectively.

[0024] In this embodiment, the cross-section of the strip groove is an inverted T-shape, the lower part of the shaft end slider 8 is an inverted T-shaped block adapted to the strip groove, and the upper part is a rectangular plate. The four apex corners of the rectangular plate are respectively threadedly connected and fixed to the positioning screw holes on the front and rear sides of the strip groove 6 by bolts. The positioning screw holes on the front and rear sides of the strip groove 6 are evenly distributed from left to right.

[0025] In this embodiment, the two ends of the limiting rod 11 are fixed to the supporting limiting blocks 7 at both ends of the supporting rod 5 by bolts. Multiple pressure blocks 17, which are the same number as the mounting base 9 and are in the same position, are placed on its bottom surface. The pressure blocks 17 are pressed onto the mounting base 9, and their top surfaces abut against the bottom surface of the limiting rod 11.

[0026] In this embodiment, sliding sleeves 18 are also installed on both sides of the guide rail 16, and the sliding sleeves 18 are hinged to the upper and lower sliding blocks 14 on the side via two rocker arms.

[0027] In this embodiment, a guide sleeve 19 is provided on the outer side of the support limiting block 7, and a guide rod 20 is passed through the upper and lower guide sleeves 19. The upper and lower ends of the guide rod 20 are fixedly connected to the upper frame 2 and the lower frame 3, respectively.

[0028] In this embodiment, the thermoplastic sizing layer spraying assembly includes spraying devices symmetrically arranged on the left and right sides of the fiber spreading assembly. Each spraying device includes two first spraying heads 21 symmetrically arranged vertically. The two first spraying heads 21 are respectively installed on the bottom surface of the upper frame 2 and the top surface of the lower frame 3. Horizontally arranged support plates 22 are installed on the outer sides of two corresponding support columns 4. Second spraying heads 23 are respectively installed on the top and bottom surfaces of the support plates 22.

[0029] In this embodiment, the two first spray nozzles 21 are respectively installed on the bottom surface of the upper frame 2 and the top surface of the lower frame 3 via lifting cylinders 24, and the two second spray nozzles 23 are respectively installed on the top and bottom surfaces of the support plate 22 via lifting cylinders 24.

[0030] In this invention, a thermoplastic sizing layer is sprayed onto the fiber surface during the fiber spreading process before conventional impregnation treatment. This results in a high degree of impregnation of the continuous fiber reinforced composite filaments and a reduction in internal defects in the formed parts. The invention employs a combination of a thermoplastic sizing layer spraying assembly and a fiber spreading assembly. During use, the number and position of the fiber spreading rollers 10 can be adjusted according to actual needs. The spraying heads are divided into four groups for counter-spraying, which facilitates flexible use and adjustment according to the fiber feeding and discharging positions. This effectively ensures the uniformity of the thermoplastic sizing layer on the fiber surface and guarantees the effect of subsequent conventional impregnation treatment.

[0031] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A method for secondary impregnation and fiber production of composite filaments suitable for additive manufacturing, characterized in that: First, the fiber (1) is spread using the fiber spreading assembly. During the spreading process, a thermoplastic sizing layer is sprayed onto the surface of the fiber (1) using the thermoplastic sizing layer spraying assembly. Then, an impregnation treatment is performed. Both the fiber spreading assembly and the thermoplastic sizing layer spraying assembly are mounted on a frame. The frame includes an upper frame (2) and a lower frame (3) arranged vertically. Both the upper frame (2) and the lower frame (3) are horizontally arranged rectangular plate structures. Vertical support columns (4) are provided near the four corners of the two. The upper and lower ends of the support columns (4) are fixedly connected to the upper frame (2) and the lower frame (3) respectively. The fiber spreading assembly includes two symmetrically arranged fiber spreading devices, each including two vertically arranged support components. Each support component includes a horizontally arranged support rod (5). The top of the support rod (5) has a horizontally arranged strip groove (6), and symmetrically detachable support limiting blocks (7) are provided at both ends. A sliding block (8) is mounted in the strip groove, and a mounting seat (9) is detachably mounted on the top of the sliding block (8). A longitudinally arranged fiber spreading roller (10) is provided between the two corresponding mounting seats (9), and the mounting seat (9) is mounted on the fiber spreading roller (10). At the end of the support rod (5), a horizontally arranged limiting rod (11) is provided above the support rod (5). A slide rail (12) is provided at the bottom of the upper support rod (5) along the horizontal direction. A slide rail (12) is provided at the top of the limiting rod (11) below. A fixed block (13) is provided in the middle of the slide rail (12). Sliding blocks (14) that can slide along it are provided on both sides. The upper and lower sliding blocks (14) on the side are hinged to the upper and lower fixed blocks (13) in the middle by an X-shaped connecting rod. A moving trolley (15) is installed at the intersection of the X-shaped connecting rod. A horizontally arranged guide rail (16) is provided between the upper and lower fiber spreading devices. The trolley (15) can slide left and right on the guide rail (16), and the two ends of the guide rail (16) are fixedly connected to the support columns (4) on both sides respectively; the thermoplastic coating layer spraying assembly includes spraying devices symmetrically arranged on the left and right sides of the fiber spreading assembly. The spraying device includes two first spraying heads (21) symmetrically arranged up and down. The two first spraying heads (21) are respectively installed on the bottom surface of the upper frame (2) and the top surface of the lower frame (3). The two corresponding support columns (4) are fitted with horizontally arranged support plates (22). The top and bottom surfaces of the support plates (22) are respectively fitted with second spraying heads (23).

2. The method for secondary impregnation and fiber production of composite filaments suitable for additive manufacturing according to claim 1, characterized in that: The cross section of the strip groove is an inverted T-shape. The lower part of the shaft end slider (8) is an inverted T-shaped block that matches the strip groove, and the upper part is a rectangular plate. The four corners of the rectangular plate are respectively fixed by bolts to the positioning screw holes on the front and rear sides of the strip groove (6). The positioning screw holes on the front and rear sides of the strip groove (6) are evenly distributed from left to right.

3. The method for secondary impregnation and fiber production of composite filaments suitable for additive manufacturing according to claim 1, characterized in that: The two ends of the limiting rod (11) are fixed to the support limiting blocks (7) at both ends of the support rod (5) by bolts. Multiple pressure blocks (17) with the same number and corresponding positions as the mounting base (9) are placed on its bottom surface. The pressure blocks (17) are pressed onto the mounting base (9), and their top surfaces abut against the bottom surfaces of the limiting rod (11).

4. The method for secondary impregnation and fiber production of composite filaments suitable for additive manufacturing according to claim 1, characterized in that: The guide rail (16) is also equipped with sliding sleeves (18) that can slide along it. The sliding sleeves (18) are hinged to the upper and lower sliding blocks (14) on the side by two rocker arms respectively.

5. The method for secondary impregnation and fiber production of composite filaments suitable for additive manufacturing according to claim 1, characterized in that: The outer side of the support limiting block (7) is provided with a guide sleeve (19), and a guide rod (20) is passed through the upper and lower guide sleeves (19). The upper and lower ends of the guide rod (20) are fixedly connected to the upper frame (2) and the lower frame (3) respectively.

6. The method for secondary impregnation and fiber production of composite filaments suitable for additive manufacturing according to claim 1, characterized in that: The two first spray nozzles (21) are installed on the bottom surface of the upper frame (2) and the top surface of the lower frame (3) respectively via lifting cylinders (24), and the two second spray nozzles (23) are installed on the top and bottom surfaces of the support plate (22) respectively via lifting cylinders (24).

Images