Continuous fiber reinforced composite 3D printing nozzle capable of improving fiber extrusion deformation at nozzle outlet

Abstract

The invention relates to a continuous fiber reinforced composite 3D printing nozzle capable of improving fiber extrusion deformation at an outlet of the nozzle, a feeding channel is arranged in the nozzle, and the feeding channel comprises a vertical section (2) and a bending contraction section (3); a universal rotating joint (1) connected with the printing head is arranged at the head end of the spray head; and a pressing sheet (4) is arranged at the tail end of the sprayer, namely a nozzle opening. According to the invention, the resin extrusion angle is changed, and the bending angle of the spray head and the length of the tile-shaped pressing sheet are controlled, so that the serious deformation of fiber bundles in the 3D printing process is reduced, the cracks of composite wires are avoided, and finally better fiber alignment, fewer gap defects and fewer fiber fractures are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of 3D printing, and in particular relates to a continuous fiber reinforced composite material 3D printing nozzle capable of improving fiber extrusion deformation at a nozzle outlet. Background Art

[0002] Continuous fiber reinforced composite materials have a series of advantages such as high specific strength, high specific modulus, low density, designability of material properties, good fatigue resistance and durability, etc. They are widely used in aerospace, automobile manufacturing, industrial equipment and other fields. 3D printing technology has the advantages of cost saving, high production efficiency, high degree of freedom in the printing process, and the ability to prepare parts with complex shapes. Based on 3D printing technology, continuous fiber reinforced composite materials are prepared by layer-by-layer deposition, which solves the problems of high mold cost and limited complexity of mold structure, thus promoting its research and development in the field of 3D printing.

[0003] As one of the main methods of FDM technology, the in-situ impregnation process is based on the principle of simultaneously feeding the continuous fiber bundle and the thermoplastic resin wire matrix into the print head, so that the molten resin matrix wraps the continuous fiber bundle, and is extruded from the nozzle at the same time to prepare the sample on the base plate in a layer-by-layer deposition manner. However, the nozzles currently on the market are upright nozzles, so there is a large bending radius between the nozzle and the printing direction during the printing process, so that the composite wire is squeezed by the edge of the nozzle head and deformed greatly, which easily causes cracks in the composite wire. When the toughness of the fiber bundle is not enough, it will cause the fiber bundle to wear or even break. In order to improve the interlayer bonding effect of the composite wire, it is usually achieved by reducing the layer thickness between the upright nozzle and the base plate or the previous layer of composite wire, but the nozzle area is small and the pressurization time is short, which ultimately leads to high interlayer porosity. This series of problems will eventually lead to poor performance of the printed composite material. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a continuous fiber reinforced composite 3D printing nozzle that improves the fiber extrusion deformation at the nozzle outlet. The nozzle changes the resin extrusion angle and reduces the severe deformation of the fiber bundle during the 3D printing process by controlling the nozzle bending angle and the length of the tile-shaped pressing sheet, thereby avoiding cracks in the composite filament and ultimately achieving better fiber alignment, fewer void defects and fewer fiber breaks.

[0005] The present invention provides a continuous fiber reinforced composite material 3D printing nozzle which improves the fiber extrusion deformation at the nozzle outlet. A feeding channel is arranged inside the nozzle, and the feeding channel comprises a vertical section, a curved contraction section and an outlet section; a universal rotating joint connected to the print head is arranged at the head end of the nozzle; and a pressing sheet is arranged at the tail end of the nozzle, i.e., the nozzle opening.

[0006] Preferably, the nozzle and the pressing sheet are both made of metal, which includes one of brass, copper alloy, hardened steel and tungsten carbide.

[0007] Preferably, the diameter of the nozzle opening is 0.4-4 mm.

[0008] Preferably, the bending radius of the bending and contracting section is 0.5-5 cm. The bending radius of the bending and contracting section is adjusted according to the flexibility of the fiber bundle.

[0009] Preferably, the fiber bundle includes one of glass fiber, carbon fiber and aramid fiber.

[0010] Preferably, the shape of the pressing sheet is tile-shaped. The length of the pressing sheet is 3-9 mm. The length of the pressing sheet is adjusted according to the different requirements of the time of pressing of the molten resin. The width of the pressing sheet is consistent with the diameter of the nozzle opening.

[0011] Preferably, the resin includes one of polylactic acid, nylon, ABS, polycarbonate, and PEEK.

[0012] Beneficial Effects

[0013] (1) The present invention adopts a curved nozzle, and the smoothly curved nozzle cavity and the nozzle direction parallel to the floor reduce the extrusion deformation of the nozzle on the fiber;

[0014] (2) The present invention increases the pressurization time of the molten wire by arranging a tile-shaped pressing sheet on the nozzle, and the pressing sheet length can be modified according to demand, thereby ultimately reducing the interlayer porosity of the composite material;

[0015] (3) The present invention changes the resin extrusion angle and controls the nozzle bending angle and the length of the tile-shaped pressing sheet, thereby reducing the severe deformation of the fiber bundle during the 3D printing process and avoiding cracks in the composite filament, ultimately achieving better fiber alignment, fewer void defects and fewer fiber breakages, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a perspective view of the nozzle of the present invention.

[0017] Figure 2 It is a cross-sectional view of the nozzle of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0019] Example 1

[0020] Depend on Figure 1 and 2 As shown, this embodiment provides a continuous fiber reinforced composite material 3D printing nozzle for improving fiber extrusion deformation at the nozzle outlet, comprising: a feeding channel is arranged inside the nozzle, and the feeding channel includes a vertical section 2 and a bending contraction section 3; a universal rotating joint 1 connected to the print head is arranged at the head end of the nozzle; a pressing sheet 4 is arranged at the nozzle tail end, i.e., the nozzle opening, and the pressing sheet 4 is tile-shaped. In this embodiment, the bending radius of the bending contraction section 3 is selected to be 1.5 cm, the diameter of the nozzle opening is 1.5 mm, and the length of the pressing sheet 4 is 5 mm, which is installed on the 3D printing head.

[0021] 1K carbon fiber is introduced into the above-mentioned printing nozzle, and the PLA resin wire is clamped by the wire feeding gear and fed into the above-mentioned printing nozzle. After being heated by the heating module, the resin wire is in a molten state and finally extruded from the nozzle together with the carbon fiber. The extruded part is subjected to the action of the tile-shaped pressing sheet, which increases the pressure and the duration of the pressure between the molten resin of the printing layer and the previous layer of resin. Finally, the penetration of the molten resin completes the combination with the previous layer of resin. Depending on the different printing paths, the nozzle relies on a universal swivel joint to ensure that the nozzle direction is always consistent with the printing path. Relying on the larger bending radius of the curved nozzle, the serious deformation of the carbon fiber is reduced, and the cracks of the composite wire are avoided. Finally, a continuous carbon fiber reinforced PLA composite material is printed.

[0022] Due to the brittleness and fragility of carbon fiber, a curved nozzle with a bending radius of 1.5 cm was selected to reduce the deformation of the fiber bundle. The nozzle structure parallel to the bottom plate reduced the extrusion friction of the nozzle on the fiber bundle, avoiding the wear and breakage of the carbon fiber. Due to the poor fluidity of PLA resin, a 5mm tile-shaped pressing sheet was selected to increase the pressurization time to ensure a better inter-layer resin bonding effect.

[0023] Example 2

[0024] Depend on Figure 1 and 2As shown, this embodiment provides a continuous fiber reinforced composite material 3D printing nozzle that improves fiber extrusion deformation at the nozzle outlet, including: a feeding channel is arranged inside the nozzle, and the feeding channel includes a vertical section 2 and a bending contraction section 3; a universal rotating joint 1 connected to the print head is arranged at the head end of the nozzle; a pressing piece 4 is arranged at the nozzle tail end, that is, the nozzle opening, and the pressing piece 4 is tile-shaped. In this embodiment, the bending radius of the bending contraction section 3 is selected to be 0.5 cm, the diameter of the nozzle opening is 1 mm, and the length of the pressing piece 4 is 3 mm, which is installed on the 3D printing head.

[0025] 200D continuous aramid fiber is introduced into the above-mentioned printing nozzle, and the TPU resin wire is clamped by the wire feeding gear and fed into the above-mentioned printing nozzle. After being heated by the heating module, the resin wire is in a molten state and finally extruded from the nozzle together with the aramid fiber. The extruded part is subjected to the action of the tile-shaped pressing sheet, which increases the pressure and the duration of the pressure between the molten resin of the printing layer and the previous layer of resin. Finally, the penetration of the molten resin completes the combination with the previous layer of resin. Depending on the different printing paths, the nozzle relies on a universal swivel joint to ensure that the nozzle direction is always consistent with the printing path. Relying on the larger bending radius of the curved nozzle, the severe deformation of the aramid fiber is reduced, and the cracks of the composite wire are avoided. Finally, a continuous aramid fiber reinforced TPU composite material is printed.

[0026] Since aramid fibers have good toughness but are susceptible to wear and fluffing, a curved nozzle with a bending radius of 0.5 cm is selected to reduce the deformation of the fiber bundle. The nozzle structure parallel to the bottom plate reduces the extrusion friction of the nozzle on the fiber bundle, avoiding the wear, fluffing and even breakage of the aramid fibers. Since TPU resin has good fluidity, the extrusion time can be reduced, and a 3mm tile-shaped press sheet is selected.

[0027] Example 3

[0028] Depend on Figure 1 and 2 As shown, this embodiment provides a continuous fiber reinforced composite material 3D printing nozzle that improves fiber extrusion deformation at the nozzle outlet, including: a feeding channel is arranged inside the nozzle, and the feeding channel includes a vertical section 2 and a bending contraction section 3; a universal rotating joint 1 connected to the print head is arranged at the head end of the nozzle; a pressing piece 4 is arranged at the nozzle tail end, that is, the nozzle opening, and the pressing piece 4 is tile-shaped. In this embodiment, the bending radius of the bending contraction section 3 is selected to be 0.5 cm, the diameter of the nozzle opening is 2 mm, and the length of the pressing piece 4 is 7 mm, which is installed on the 3D printing head.

[0029] 2K continuous carbon fiber is introduced into the above-mentioned printing nozzle, and the ABS resin wire is clamped by the wire feeding gear and fed into the above-mentioned printing nozzle. After being heated by the heating module, the resin wire is in a molten state and finally extruded from the nozzle together with the carbon fiber. The extruded part is subjected to the action of the tile-shaped pressing sheet, which increases the pressure and the duration of the pressure between the molten resin of the printing layer and the previous layer of resin. Finally, the penetration of the molten resin completes the combination with the previous layer of resin. Depending on the different printing paths, the nozzle relies on a universal swivel joint to ensure that the nozzle direction is always consistent with the printing path. Relying on the larger bending radius of the curved nozzle, the serious deformation of the carbon fiber is reduced, and the cracks of the composite wire are avoided. Finally, a continuous carbon fiber reinforced ABS composite material is printed.

[0030] Due to the brittle nature of carbon fiber, a curved nozzle with a bending radius of 0.5 cm was selected to reduce the deformation of the fiber bundle. The nozzle structure parallel to the base plate reduced the extrusion and friction of the nozzle on the fiber bundle, avoiding the wear and breakage of the carbon fiber. Due to the poor fluidity of ABS resin, a 7mm tile-shaped pressing sheet was selected to increase the pressurization time to ensure a better inter-layer resin bonding effect.

Claims

1. A continuous fiber reinforced composite 3D printing nozzle that improves fiber extrusion deformation at the nozzle outlet, characterized in that: A feeding channel is arranged inside the nozzle, and the feeding channel comprises a vertical section (2) and a curved contraction section (3); a universal rotating joint (1) connected to a print head is arranged at the head end of the nozzle; and a pressing sheet (4) is arranged at the tail end of the nozzle, i.e., the nozzle opening.

2. The 3D printing nozzle according to claim 1, characterized in that: The nozzle and the pressing sheet (4) are both made of metal.

3. The 3D printing nozzle according to claim 2, characterized in that: The metal material includes one of brass, copper alloy, hardened steel, and tungsten carbide.

4. The 3D printing nozzle according to claim 1, characterized in that: The diameter of the nozzle opening is 0.4-4 mm.

5. The 3D printing nozzle according to claim 1, characterized in that: The bending radius of the bending contraction section (3) is 0.5-5 cm.

6. The 3D printing nozzle according to claim 1, characterized in that: The bending radius of the bending and contracting section (3) is adjusted according to the flexibility of the fiber bundle.

7. The 3D printing nozzle according to claim 1, characterized in that: The pressing sheet (4) is in the shape of a tile.

8. The 3D printing nozzle according to claim 1 or 7, characterized in that: The length of the pressed sheet (4) is 3-9 mm.

9. The 3D printing nozzle according to claim 8, characterized in that: The length of the pressing sheet (4) is adjusted according to the different pressing time requirements of the molten resin.

10. The 3D printing nozzle according to claim 7, characterized in that: The width of the pressing sheet (4) is consistent with the diameter of the nozzle opening.

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