A 3D printing nozzle for multi-strand mixed-twisted continuous fiber composite materials

Abstract

The present invention relates to the field of additive manufacturing technology, and specifically to a multi-strand mixed twisted continuous fiber composite material 3D printing nozzle; comprising a mixture box, a twisting mechanism and an extrusion mechanism; the mixture box comprises a box cover arranged on the top, and the box cover is provided with four twisting inlets and a resin inlet; a stepping motor is provided on the upper surface of the box cover; the twisting mechanism comprises a turbine, a worm, and a twisting gear, an auxiliary twisting gear A, an auxiliary twisting gear B, an auxiliary twisting gear C, an auxiliary shaft A and an auxiliary shaft B arranged in the mixture box; the extrusion mechanism comprises a gear A, a gear B, and an extrusion auxiliary shaft A, an extrusion auxiliary shaft B, an extrusion wheel A and an extrusion wheel B arranged in the mixture box. The present invention can change the twist of the continuous fiber by changing the number and type of the continuous fiber and changing the turbine parameters in the twisting mechanism, thereby realizing the preparation of diversified composite materials with different performance requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a 3D printing nozzle for a multi-strand mixed-twisted continuous fiber composite material. Background Art

[0002] Continuous fiber reinforced composite materials have high specific strength and specific modulus, good compressive stability and good design performance, and some performance aspects have reached the level of aviation aluminum, making it one of the most important structural materials in high-tech fields such as aerospace and military industry after aluminum alloys and titanium alloys.

[0003] The continuous fiber reinforced composite manufacturing technology based on additive manufacturing technology combines advanced materials and digital manufacturing technology. It can generate part entities of almost any shape through layered stacking, achieving the decoupling between manufacturing cost and manufacturing complexity, and providing a way to achieve lightweight, structural and functional integration, and high-strength design and manufacturing of continuous fiber reinforced composite products.

[0004] The continuous fiber composite material preparation process based on fused deposition modeling (FDM) technology inherits the characteristics of high reliability and wide range of forming materials of FDM technology, making this process the main development direction of additive manufacturing continuous fiber composite material technology. However, the current continuous fiber composite material molding technology based on FDM can generally only print one continuous fiber at a time, and is affected by the space in the nozzle and the viscosity of the resin. The continuous fiber has almost no twist, that is, the continuous fiber is still in the original state of the raw wire in the composite material. For continuous fibers that have not been twisted, the wettability between the fiber and the matrix is ​​low, resulting in low interfacial bonding strength between the two; on the other hand, when the untwisted continuous fiber is subjected to alternating loads, the fiber is prone to fatigue fracture, resulting in poor fatigue resistance of continuous fiber composite products. Summary of the invention

[0005] The present invention provides a multi-strand mixed-twist continuous fiber composite 3D printing nozzle, which aims to solve the defects of the existing 3D printing continuous fiber composite molding technology, such as single fiber type and poor fiber fatigue performance.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] The present invention provides a multi-strand mixed-twisted continuous fiber composite material 3D printing nozzle, comprising a mixture box, a twisting mechanism and an extrusion mechanism;

[0008] The mixed material box comprises a box cover arranged at the top, and the box cover is provided with four twisting thread inlets and one resin inlet; a stepping motor is provided on the upper surface of the box cover; a detector and an internal heating block are provided on the lower surface of the box cover, and the internal heating block is provided at the center of the box cover;

[0009] The twisting mechanism includes a turbine, a worm, and a twisting gear, an auxiliary twisting gear A, an auxiliary twisting gear B, an auxiliary twisting gear C, an auxiliary shaft A and an auxiliary shaft B arranged in the mixture box; the turbine is arranged on the output shaft of the stepping motor, the worm penetrates the box cover and is rotatably arranged, and the worm is meshed with the turbine; the auxiliary twisting gear A is sleeved and fixed on the lower half of the worm, and the upper and lower ends of the auxiliary shaft A and the auxiliary shaft B are rotatably arranged on the mixture box through bearings, the auxiliary twisting gear B is sleeved and fixed on the auxiliary shaft A, and the auxiliary twisting gear C is sleeved and fixed on the auxiliary shaft B, and the auxiliary twisting gear A, auxiliary twisting gear B and auxiliary twisting gear C are located in the same horizontal plane; an eccentric hole is arranged on the twisting gear, and the twisting gear is respectively meshed with the auxiliary twisting gear A, auxiliary twisting gear B and auxiliary twisting gear C and is clamped and fixed by the three;

[0010] The extrusion mechanism includes gear A, gear B, and extrusion auxiliary shaft A, extrusion auxiliary shaft B, extrusion wheel A and extrusion wheel B arranged in the mixture box; the gear A is fixedly connected to one end of the extrusion auxiliary shaft A, the gear B is coaxially connected and fixed with the turbine through an internal shaft, and the gear A is meshed with the gear B; the extrusion auxiliary shaft A and the extrusion auxiliary shaft B are both arranged in the mixture box through bearings, the extrusion wheel A is sleeved and fixed on the extrusion auxiliary shaft A, the extrusion wheel B is sleeved and fixed on the extrusion auxiliary shaft B, the extrusion wheel A and the extrusion wheel B are located in the same vertical plane, and the contact point between the extrusion wheel A and the extrusion wheel B is located directly below the twisting gear.

[0011] Furthermore, the detector is a temperature detector.

[0012] Furthermore, the twisting inlet and the resin inlet are both provided with throats.

[0013] Furthermore, the bearing is isolated from the solution by a gasket.

[0014] Furthermore, a slow-twist bracket is provided below the box cover, and four through holes are provided on the slow-twist bracket.

[0015] The beneficial effects achieved by the present invention are:

[0016] (1) The present invention can realize the simultaneous printing of multiple strands of the same or different types of continuous fibers;

[0017] (2) The present invention can twist the continuous fibers according to the actual product performance requirements. On the one hand, the twisting device can drive the mixing of the continuous fibers and the resin, thereby improving the impregnation between the two and thereby improving the mechanical properties of the continuous fiber composite material product. On the other hand, by twisting the continuous fibers, the fatigue resistance of the continuous fibers can be improved.

[0018] (3) The present invention can change the twist of continuous fibers by changing the number and type of continuous fibers and the turbine parameters in the twisting mechanism, thereby realizing the preparation of diversified composite materials with different performance requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0021] Figure 2 It is a partially enlarged schematic diagram of the box cover of the present invention.

[0022] Figure 3 It is a side view of the present invention.

[0023] Figure 4 It is the front view of the present invention.

[0024] Figure 5 It is a top view of the present invention.

[0025] In the figure, 1. gear A; 2. extrusion auxiliary shaft A; 3. extrusion auxiliary shaft B; 4. worm; 5-1. auxiliary twisting gear A; 5-2. auxiliary twisting gear B; 5-3. auxiliary twisting gear C; 6-1. auxiliary shaft A; 6-2. auxiliary shaft B; 7. gear B; 8. turbine; 9. stepper motor; 10. box cover; 11. twisting gear; 12. extrusion wheel A; 13. extrusion wheel B; 14. bearing; 15. detector; 16. internal heating block; 17. twisting inlet; 18. resin inlet; 19. slow twisting bracket; 20. throat. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0028] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if the meaning of "and / or" appearing in the full text is to include three parallel schemes, taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0029] The present invention proposes a multi-strand mixed twist continuous fiber composite 3D printing nozzle. By adding a twisting mechanism and an extrusion mechanism, multiple strands of the same fiber or different types of fibers can be twisted in the nozzle, and the fibers and resin can be evenly mixed, thereby improving the strength and toughness of the 3D printed continuous fiber composite material. In addition, by controlling the number, type and twist of the continuous fibers, the controllable preparation of diversified parts can be met.

[0030] like Figures 1 to 5 As shown, the present invention provides a multi-strand mixed twisted continuous fiber composite material 3D printing nozzle, including a mixture box (not shown in the figure), a twisting mechanism and an extrusion mechanism;

[0031] The mixed material box includes a box cover 10 arranged on the top, and the box cover 10 is provided with four twisting inlets 17 and a resin inlet 18, which can control the type and quantity of continuous fibers according to needs; the upper surface of the box cover 10 is provided with a stepper motor 9, and the stepper motor 9 is the power source of the present invention; the lower surface of the box cover 10 is provided with a detector 15 and an internal heating block 16, and the detector 15 is a temperature detector 15, and the internal heating block 16 is arranged at the center of the box cover 10. Among them, the twisting inlet 17 and the resin inlet 18 are both provided with a throat 20.

[0032] The twisting mechanism includes a turbine 8, a worm 4, and a twisting gear 11, an auxiliary twisting gear A5-1, an auxiliary twisting gear B5-2, an auxiliary twisting gear C5-3, an auxiliary shaft A6-1 and an auxiliary shaft B6-2 arranged in the mixed material box; the turbine 8 is arranged on the output shaft of the stepping motor 9, the worm 4 penetrates the box cover 10 and is rotatably arranged, the upper and lower ends of the worm 4, that is, the contact points with the box cover 10 are fixed by bearings 14, and the worm 4 is meshed with the turbine 8; the auxiliary twisting gear A5-1 is sleeved and fixed on the lower half of the worm 4, and the auxiliary shaft A6- 1 and the upper and lower ends of the auxiliary shaft B6-2 are rotatably arranged on the mixture box through bearings 14, the auxiliary twisting gear B5-2 is sleeved and fixed on the auxiliary shaft A6-1, and the auxiliary twisting gear C5-3 is sleeved and fixed on the auxiliary shaft B6-2, and the auxiliary twisting gear A5-1, auxiliary twisting gear B5-2 and auxiliary twisting gear C5-3 are located in the same horizontal plane; an eccentric hole is arranged on the twisting gear 11, and the twisting gear 11 is respectively meshed with the auxiliary twisting gear A5-1, auxiliary twisting gear B5-2 and auxiliary twisting gear C5-3 and is clamped and fixed by the three.

[0033] During operation, the stepping motor 9 is started, the turbine 8 rotates to drive the worm 4, and the auxiliary twisting gear A5-1 on the same axis as the worm 4 rotates to drive the twisting gear 11. The twisting gear 11 rotates under the limit of the auxiliary twisting gear A5-1, the auxiliary twisting gear B5-2 and the auxiliary twisting gear C5-3.

[0034] Limiting structures such as baffles may also be provided in the mixture box to prevent the twisting gear 11 from moving along the axis.

[0035] The extrusion mechanism includes a gear A1, a gear B7, and an extrusion auxiliary shaft A2, an extrusion auxiliary shaft B3, an extrusion wheel A12 and an extrusion wheel B13 arranged in the mixed material box; the gear A1 is fixedly connected to one end of the extrusion auxiliary shaft A2, the gear B7 is coaxially connected and fixed to the turbine 8 through an internal shaft, and the gear A1 is meshed with the gear B7; the extrusion auxiliary shaft A2 and the extrusion auxiliary shaft B3 are both arranged in the mixed material box through a bearing 14, the extrusion wheel A12 is sleeved and fixed on the extrusion auxiliary shaft A2, the extrusion wheel B13 is sleeved and fixed on the extrusion auxiliary shaft B3, the extrusion wheel A12 and the extrusion wheel B13 are located in the same vertical plane, and the contact point between the extrusion wheel A12 and the extrusion wheel B13 is located directly below the twisting gear 11. The gear B7 rotates to drive the gear A1, and the extrusion wheel A12 on the same axis as the gear A1 rotates to extrude the twisted continuous fiber.

[0036] When working, the extrusion mechanism drives the rotation of gear A1 and gear B7 through the motor to evenly pull out the twisted and impregnated continuous fiber / resin composite material, and extrude it from the nozzle to deposit and solidify on the working platform; and the extrusion mechanism can provide downward traction for the twisting process to ensure the consistency of the twist of the continuous fibers in the composite material.

[0037] Furthermore, the bearing 14 isolates the solution through a gasket to prevent the solution in the mixture box from leaking to the outside.

[0038] Furthermore, the twisted yarn and the resin enter the box through the box cover 10, and the thermoplastic resin is dissolved into a molten state by the internal heating block 16.

[0039] Furthermore, the present invention also includes a controller, which is the control center of the present invention, and controls the start and stop of the stepper motor 9 and the internal heating block 16 according to the monitoring data. The controller is a single chip microcomputer or a PLC controller, etc. The function of the controller is not difficult for technicians in this field to realize, and does not require creative labor, so it is not described in detail.

[0040] Furthermore, when the detector 15 in the box cover 10 senses a certain temperature, the controller will start the extrusion mechanism and the twisting mechanism to move.

[0041] Furthermore, the twisting mechanism drives the twisting gear 11 to rotate through the rotation of the turbine 8 and the worm 4, so that the continuous fibers in the resin are twisted together at high speed, and the rotation of the continuous fibers promotes the infiltration and fusion between the continuous fibers and the resin matrix, thereby improving the bonding force between the fibers and the resin.

[0042] Furthermore, a slow twisting bracket 19 is provided below the box cover 10, and four through holes are provided on the slow twisting bracket 19, and the four through holes correspond to the four twisting inlets 17 of the box cover 10. The function of the slow twisting bracket 19 is to prevent the four continuous fibers from being twisted too early, and to ensure that the continuous fibers just entering are fully contacted with the resin solution before being twisted together.

[0043] Specifically, the workflow of the present invention is:

[0044] The first step: conveying the continuous fiber and the thermoplastic resin filament into the mixing material box through the box cover 10 throat 20, under the action of the internal heating block 16, the resin material changes from solid to molten state, and the continuous fiber is fully in contact with the molten resin.

[0045] Further: When the resin material changes from a solid state to a molten state, the controller receives the command and starts the extrusion mechanism and the twisting mechanism. The twisting mechanism drives the twisting gear 11 to rotate through the rotation of the turbine 8 and the worm 4, and each continuous fiber is twisted together at high speed through the rotation of the twisting gear 11. The stepper motor 9 drives the gear A1 to rotate through the gear B7, and then drives the extrusion wheel A12 and the extrusion wheel B13 to rotate, and the impregnated and twisted continuous fiber composite material is uniformly extruded, and at the same time, a downward force is applied to the continuous fibers in the twisting mechanism to ensure the uniformity of the continuous fiber twisting.

[0046] Further: the continuous fibers impregnated with the resin material and twisted are extruded through the rotation of the extrusion wheels A12 and B13 in the extrusion mechanism, and are deposited and solidified on the working platform according to a predetermined trajectory.

[0047] When the patent of the present invention is in use, the type, quantity and type of continuous fiber and resin can be selected according to demand to enter the nozzle; then the heating block is made to reach the melting temperature of the resin to melt the resin material, and the meshing rotation of the turbine 8 and the worm 4 drives the coaxial auxiliary twisting gear A5-1 on the worm 4, and the auxiliary twisting gear A5-1 meshes with the twisting gear 11 to rotate at high speed to twist multiple strands of continuous fibers into one; the rotation of gear A1 and gear B7 will drive the extrusion wheel A12 and the extrusion wheel B13 to rotate, and then the twisted continuous fiber composite material will be evenly extruded.

[0048] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A multi-strand mixed-twisted continuous fiber composite material 3D printing nozzle, characterized in that: It includes a mixing box, a twisting mechanism and an extrusion mechanism; The mixed material box comprises a box cover (10) arranged at the top, and the box cover (10) is provided with four twisting thread inlets (17) and a resin inlet (18); a stepping motor (9) is arranged on the upper surface of the box cover (10); a detector (15) and an internal heating block (16) are arranged on the lower surface of the box cover (10), and the internal heating block (16) is arranged at the center of the box cover (10); The twisting mechanism comprises a turbine (8), a worm (4), a twisting gear (11), an auxiliary twisting gear A (5-1), an auxiliary twisting gear B (5-2), an auxiliary twisting gear C (5-3), an auxiliary shaft A (6-1) and an auxiliary shaft B (6-2) arranged in the mixed material box; the turbine (8) is arranged on the output shaft of the stepping motor (9); the worm (4) penetrates the box cover (10) and is rotatably arranged; the worm (4) is meshed with the turbine (8); the auxiliary twisting gear A (5-1) is sleeved and fixed on the lower half of the worm (4); the upper ends of the auxiliary shafts A (6-1) and B (6-2) are The lower ends are rotatably arranged on the mixed material box body through bearings (14); the auxiliary twisting gear B (5-2) is sleeved and fixed on the auxiliary shaft A (6-1); the auxiliary twisting gear C (5-3) is sleeved and fixed on the auxiliary shaft B (6-2); the auxiliary twisting gear A (5-1), the auxiliary twisting gear B (5-2) and the auxiliary twisting gear C (5-3) are located in the same horizontal plane; an eccentric hole is arranged on the twisting gear (11); the twisting gear (11) is respectively meshed with the auxiliary twisting gear A (5-1), the auxiliary twisting gear B (5-2) and the auxiliary twisting gear C (5-3) and is clamped and fixed by the three; The extrusion mechanism comprises a gear A (1), a gear B (7), and an extrusion auxiliary shaft A (2), an extrusion auxiliary shaft B (3), an extrusion wheel A (12) and an extrusion wheel B (13) arranged in the mixed material box; the gear A (1) is fixedly connected to one end of the extrusion auxiliary shaft A (2), the gear B (7) is coaxially connected and fixed to the turbine (8) through an internal shaft, and the gear A (1) is meshed with the gear B (7); the extrusion auxiliary shaft A (2) and the extrusion auxiliary shaft B (3) are both arranged in the mixed material box through a bearing (14), the extrusion wheel A (12) is sleeved and fixed on the extrusion auxiliary shaft A (2), and the extrusion wheel B (13) is sleeved and fixed on the extrusion auxiliary shaft B (3), the extrusion wheel A (12) and the extrusion wheel B (13) are located in the same vertical plane, and the contact point between the extrusion wheel A (12) and the extrusion wheel B (13) is located directly below the twisting gear (11).

2. A multi-strand mixed-twisted continuous fiber composite material 3D printing nozzle according to claim 1, characterized in that: The detector (15) is a temperature detector (15).

3. The multi-strand mixed-twisted continuous fiber composite material 3D printing nozzle according to claim 1, characterized in that: The twisting inlet (17) and the resin inlet (18) are both provided with a throat (20).

4. The multi-strand mixed-twisted continuous fiber composite material 3D printing nozzle according to claim 1, characterized in that: The bearing (14) is isolated from the solution by a gasket.

5. The multi-strand mixed-twisted continuous fiber composite material 3D printing nozzle according to claim 1, characterized in that: A slow-twist bracket (19) is arranged below the box cover (10), and four through holes are arranged on the slow-twist bracket (19).

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