Continuous fiber 3D printing nozzle structure and composite product

Abstract

The application provides a continuous fiber 3D printing nozzle structure and a composite material product, and belongs to the technical field of continuous fiber 3D printing manufacturing devices. The nozzle structure comprises a hollow columnar nozzle head, a rolling device and a shell. The rolling device is located at the front end of the hollow columnar nozzle head, and the shell surrounds the outer periphery of the hollow columnar nozzle head. The inner wall of the shell and the outer side wall of the hollow columnar nozzle head form a storage cavity for storing fillers. The rolling device comprises a regular polygon mounting frame and rolling blocks. Each side of the mounting frame serves as a mounting shaft, and each mounting shaft is provided with a rolling block rotatably. The raw material extruded from the hollow columnar nozzle head passes through the space surrounded by the plurality of rolling blocks. The rolling blocks are pressed on the surface of the extruded wire during the movement of the 3D printing nozzle. The bottom wall of the shell is provided with a filler conveying assembly, which is used for conveying the fillers in the storage cavity to the outer surface of the rolling blocks. The application can reduce the risk of hairiness and wire breakage of the wire during the printing process.

Description

Technical Field

[0001] This application relates to the field of continuous fiber 3D printing manufacturing apparatus, and more particularly to a continuous fiber 3D printing nozzle structure and composite material product. Background Technology

[0002] Continuous fiber 3D printing is a process that manufactures composite material parts by stacking resin-impregnated continuous fiber filaments layer by layer. Compared with traditional composite material processes such as compression molding and pultrusion, continuous fiber 3D printing has advantages such as strong designability, no mold dependence, and suitability for manufacturing complex structures, making it of significant application value in advanced manufacturing fields such as aerospace, shipbuilding, and automotive.

[0003] like Figure 1 As shown, in the continuous fiber 3D printing process, the raw material filament is fed to the filament outlet by the filament feeding mechanism and heated to soften. It is then extruded by the filament feeding mechanism to the front end of the filament outlet of the printing nozzle. Under the heat and extrusion force applied to the filament at the front end of the filament outlet of the printing nozzle, the filament 4 is deformed into a specific size and shape and accumulated on the forming platform 5. The accumulation of several filaments layer by layer completes the 3D printing of a part.

[0004] However, during 3D printing, in addition to the pressure applied by the printing nozzle, the filament is also subjected to frictional forces generated by its contact with the inner wall of the nozzle's filament outlet. Because the inner wall of the nozzle's filament outlet is difficult to finely polish, the roughness of the inner wall of the nozzles used in current 3D printing equipment, both domestically and internationally, is generally quite high. Therefore, significant sliding friction is generated between the filament and the front end face of the nozzle's filament outlet during printing. Under this high friction, the filament is highly susceptible to serious problems such as fuzzing and filament breakage during printing, leading to internal defects in the printed parts or even interrupting the printing process.

[0005] The high contact friction between the printing nozzle and the filament causes damage such as fuzzing and filament breakage, which seriously affects the forming quality and continuous stability of the printing process in 3D printing. This restricts the further application of continuous fiber 3D printing technology in advanced engineering fields. How to achieve low-damage printing of filaments in the 3D printing process is worthy of in-depth research.

[0006] Furthermore, filler mixing is an important way to modify and improve the functional properties of composite materials. However, existing continuous fiber 3D printing equipment generally lacks a dedicated device for adding mixed fillers; if you want to mix different functional modified fillers into 3D printed composite materials, you often need to manually spread functional fillers between the layers of the 3D printed material, which is a cumbersome process and makes it difficult to control the uniformity of mixing. Summary of the Invention

[0007] In view of this, this application provides a continuous fiber 3D printing nozzle structure and composite material product, which solves the problems in the prior art and reduces the risk of fuzzing and filament breakage during the printing process.

[0008] On the one hand, the continuous fiber 3D printing nozzle structure provided in this application adopts the following technical solution:

[0009] A continuous fiber 3D printing nozzle structure includes a hollow cylindrical nozzle, a rolling device, and a shell. The central through hole inside the hollow cylindrical nozzle serves as the filament outlet through which the printing raw material passes. The rolling device is located at the front end of the hollow cylindrical nozzle. The shell surrounds the outer periphery of the hollow cylindrical nozzle, and the inner wall of the shell and the outer wall of the hollow cylindrical nozzle form a storage cavity for storing filler.

[0010] The rolling device includes a regular polygonal mounting frame and rolling blocks. Each side of the regular polygonal mounting frame serves as a mounting axis. A rolling block is rotatably mounted on each mounting axis of the mounting frame. The rotation axis of the rolling block is coaxial with the mounting axis on which the rolling block is located. The cross-section of the rolling block in the direction perpendicular to the axis of the mounting axis is circular. The raw material extruded from the hollow cylindrical nozzle passes through the space enclosed by multiple rolling blocks. During the movement of the 3D printing nozzle, at least one rolling block presses firmly onto the surface of the extruded filament.

[0011] The bottom wall of the outer casing is provided with a filler conveying assembly, which is used to convey the filler of the storage cavity to the outer surface of the rolling block.

[0012] Optionally, the packing conveying assembly includes a packing supply chamber corresponding to each rolling block. The bottom of the packing supply chamber is provided with a discharge port, the edge of which is engaged with the outer surface of the rolling block. The top of the packing supply chamber is connected to the bottom of the storage chamber. The bottom of the packing supply chamber or the storage chamber is provided with an opening and closing assembly for controlling the connection or closure of the packing supply chamber and the storage chamber.

[0013] Optionally, the opening and closing assembly includes a movable plate, and the filler supply chamber is provided with a groove along the radial direction of the wire outlet hole. The filler supply chamber has an opening on the side opposite to the axis of the hollow cylindrical nozzle. The movable plate passes through the opening and is inserted into the groove. The movable plate slides in the groove along the radial direction of the wire outlet hole.

[0014] Optionally, the mounting bracket is in the shape of a regular octagon or a regular decagon.

[0015] Optionally, the rolling block is a roller or a ball.

[0016] Optionally, the rolling block has a thermal conductivity greater than or equal to 250. Metallic materials, among which, Watts per meter per Kelvin is a unit of thermal conductivity.

[0017] Optionally, the outer periphery of the rolling block has a coating, the coating having a thermal conductivity greater than or equal to 250. Metallic materials, among which, Watts per meter per Kelvin is a unit of thermal conductivity.

[0018] Optionally, the surface roughness Ra of the rolling block is ≤1.6μm.

[0019] Optionally, the mounting bracket is made of a self-lubricating material or the surface of the mounting bracket is provided with a self-lubricating material.

[0020] On the other hand, the continuous fiber 3D printed composite material product provided in this application adopts the following technical solution:

[0021] A continuous fiber 3D printed composite material product is manufactured using a 3D printing device with the aforementioned continuous fiber 3D printing nozzle structure. The storage cavity contains filler, and during the printing process, the filler delivery assembly delivers the filler from the storage cavity to the outer surface of the rolling block.

[0022] In summary, this application includes the following beneficial technical effects:

[0023] Compared to existing traditional printing nozzles, the novel printing nozzle proposed in this application can effectively reduce the frictional force on the filament during 3D printing, thereby controlling frictional damage to the filament and reducing the frequent filament fuzzing and breakage defects that occur in current continuous fiber 3D printing processes. This also mitigates the time and economic costs wasted due to forced reprinting caused by filament damage. Simultaneously, the rolling and compacting action of the rolling device on the printed continuous fiber filament can also effectively reduce the surface roughness of the 3D printed parts.

[0024] The novel printing nozzle proposed in this application can automatically and uniformly apply functional modified fillers to the surface of the filament through rolling contact between the rolling device and the filament, promoting the tight bonding between the filament and the filler, realizing the in-situ mixing preparation of functional filler modified 3D printing composite materials, improving the functional properties of 3D printing composite materials, and expanding their application scope. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of a 3D printing nozzle structure in the prior art;

[0027] Figure 2 This is a schematic diagram of the overall structure of the continuous fiber 3D printing nozzle structure of this application;

[0028] Figure 3 This is a schematic diagram of the continuous fiber 3D printing nozzle structure from another perspective of the present application.

[0029] Figure 4 This is a schematic diagram of the continuous fiber 3D printing nozzle structure printing process of this application;

[0030] Figure 5 This is a schematic diagram of the rolling device when the rolling block is a roller in this application;

[0031] Figure 6 This is a schematic diagram of the rolling device when the rolling block in this application is a ball bearing;

[0032] Figure 7 This is a schematic diagram of the mounting frame when the rolling block in this application is a ball bearing.

[0033] Explanation of reference numerals in the attached drawings: 1. Hollow cylindrical nozzle; 11. Wire outlet hole; 12. External thread; 2. Rolling device; 21. Mounting bracket; 22. Rolling block; 23. Mounting shaft; 24. Roller; 25. Ball bearing; 3. Outer shell; 31. Storage cavity; 32. Filler supply cavity; 33. Discharge port; 34. Opening and closing assembly; 4. Wire material; 5. Forming platform. Detailed Implementation

[0034] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0035] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0037] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0038] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0039] This application provides a continuous fiber 3D printing nozzle structure.

[0040] like Figure 2 , Figure 3 and Figure 4 As shown, a continuous fiber 3D printing nozzle structure includes a hollow cylindrical nozzle 1, a rolling device 2, and a housing 3. The central through hole inside the hollow cylindrical nozzle 1 serves as the filament outlet 11 through which the printing raw material passes. The rolling device 2 is located at the front end of the hollow cylindrical nozzle 1. The housing 3 surrounds the outer periphery of the hollow cylindrical nozzle 1. The inner wall of the housing 3 and the outer wall of the hollow cylindrical nozzle 1 form a storage cavity 31 for storing filler.

[0041] The rolling device 2 includes a regular polygonal mounting frame 21 and rolling blocks 22. Each side of the regular polygonal mounting frame 21 serves as a mounting axis 23. A rolling block 22 is rotatably mounted on each mounting axis 23 of the mounting frame 21. The rotation axis of the rolling block 22 is coaxial with the mounting axis 23 on which the rolling block 22 is located. The cross-section of the rolling block 22 in the direction perpendicular to the axis of its mounting axis 23 is circular. The raw material extruded from the hollow cylindrical nozzle 1 accumulates on the forming platform 5 after passing through the space enclosed by multiple rolling blocks 22. During the movement of the 3D printing nozzle, at least one rolling block 22 presses firmly onto the surface of the extruded filament 4. In this embodiment, the mounting frame 21 is fixedly mounted on the outer front end of the hollow cylindrical nozzle 1 by a metal connecting rod. The two ends of the metal connecting rod are welded to the mounting frame 21 and the hollow cylindrical nozzle 1, respectively, to realize the installation of the rolling device 2 at the front end of the hollow cylindrical nozzle 1. The side length design of the mounting frame 21 allows adjacent rolling blocks 22 to fit together and rotate freely.

[0042] In this application, a rolling block 22 is provided at the front end of the hollow cylindrical nozzle 1. During the printing process, the rolling block 22 at the front end of the nozzle and the filament 4 are subjected to rolling friction. Compared with sliding friction, under the same pressure applied to the filament 4, this application reduces the frictional force between the front end of the nozzle and the filament 4, which can effectively reduce the frictional damage caused to the filament 4 by the front end of the printing nozzle filament outlet 11 during the printing process, and reduce process problems such as fuzzing and filament breakage of the filament 4 during the printing process.

[0043] The bottom wall of the outer shell 3 is provided with a filler delivery assembly, which is used to deliver the filler in the storage cavity 31 to the outer surface of the rolling block 22. As the nozzle moves and the rolling block 22 rolls, the filler on the outer surface of the rolling block 22 is pressed firmly against the surface of the newly printed filament 4 and adheres tightly to the filament 4, realizing the mixing of filler at the interlayer interface of the continuous fiber 3D printed sample. By adding different types of functional fillers, continuous fiber 3D printed composite materials can be endowed with multiple functional properties such as wave absorption, thermal conductivity, and electrical conductivity, realizing the integration of structure and function.

[0044] In this embodiment of the application, the packing conveying assembly includes a packing supply chamber 32 corresponding to the rolling block 22. Multiple packing supply chambers 32 are spaced apart. The bottom of the packing supply chamber 32 is provided with a discharge port 33. The edge of the discharge port 33 is engaged with the outer surface of the rolling block 22. The top of the packing supply chamber 32 is connected to the bottom of the storage chamber 31. The bottom of the packing supply chamber 32 or the storage chamber 31 is provided with an opening and closing assembly 34 for controlling the connection or closing of the packing supply chamber 32 and the storage chamber 31.

[0045] In one embodiment, the outer shell 3 is frustum-shaped, with the smaller diameter end of the frustum-shaped outer shell 3 serving as the bottom of the storage cavity 31 and fixedly connected to the outer side wall of the hollow columnar nozzle 1, and the larger diameter end of the frustum-shaped outer shell 3 being open.

[0046] In one embodiment, the opening / closing assembly 34 includes a movable plate. The inner wall of the filler supply chamber 32 is provided with a groove along the radial direction of the wire outlet hole 11. The filler supply chamber 32 has an opening on the side facing away from the axis of the hollow cylindrical nozzle 1. The movable plate passes through the opening and is inserted into the groove. The movable plate slides in the groove along the radial direction of the wire outlet hole 11. Inserting the movable plate interrupts the supply of filler to the rolling block 22. When the movable plate is pulled out, the filler in the storage chamber 31 is supplied to the outer surface of the rolling block 22 through the filler supply chamber 32. By controlling how much the movable plate is pulled out, the supply flow rate of the filler can be controlled. Applicable filler physical states include, but are not limited to, particles, powders, slurries, liquids, etc., and applicable filler types include, but are not limited to, microwave absorbing fillers, microwave transparent fillers, thermally conductive fillers, electrically conductive fillers, heat-resistant fillers, sound-absorbing fillers, etc. Moreover, in this embodiment, the bottom wall of the filler supply chamber 32 and the outer surface of the rolling block 22 are fitted together, and there is a gap between them to provide space for filler discharge.

[0047] In this embodiment, the mounting bracket 21 is made of a self-lubricating material or has a self-lubricating material coating on its surface, and the self-lubricating material is a tin-based alloy. The rolling block 22 has a thermal conductivity greater than or equal to 250. The rolling block 22 is made of a metallic material; or, the outer periphery of the rolling block 22 is coated with a coating having a thermal conductivity greater than or equal to 250. Metallic materials, among which, Watts per meter per Kelvin is a unit of thermal conductivity.

[0048] In a specific embodiment, the rolling block 22 is a copper-tungsten alloy or a copper-beryllium alloy; or the outer periphery of the rolling block 22 is coated with a copper-tungsten alloy or a copper-beryllium alloy to achieve thermal conductivity and wear resistance of the rolling block 22.

[0049] The surface roughness Ra of the rolling block 22 is ≤1.6μm, further reducing frictional damage during the printing process of the filament 4.

[0050] The hollow cylindrical nozzle 1 of this application embodiment has an external thread 12 at the end away from the rolling device 2. It can directly replace the traditional printing nozzle on the 3D printing equipment through threaded installation. It can achieve the effect of reducing printing friction damage in multiple printing directions without changing other mechanical structures of the 3D printing equipment. The mechanical structure is simple and easy to replace.

[0051] like Figure 5As shown, the rolling block 22 can be a roller 24, and the mounting bracket 21 is octagonal. A through hole is formed on the roller 24, and the roller 24 and the through hole are coaxial. The through hole is used to install the shaft 23, which passes through it to realize the rotation of the roller 24. In order to adapt to the commonly used 3D printing filament 4 specifications, the diameter of the roller 24 is in the range of 0.1-1mm, and the axial length of the roller 24 is in the range of 0.2-1.4mm. In a specific embodiment, the surface roughness Ra of the roller 24 is ≤1.6μm, the diameter of the roller 24 is 0.35mm, the axial length of the roller 24 is 0.9mm, the diameter of the through hole is 0.2mm, and the side length of the mounting bracket 21 is 1mm. The nozzle structure of this embodiment can be matched with the 3D printing needs of commonly available 1K or 3K continuous fiber filaments 4. Taking the 3D printing of 0.6mm diameter 3K continuous glass fiber reinforced nylon filament as an example, the average filament breakage frequency using a traditional nozzle structure is 1 hour / time, and the surface roughness Ra of the printed sample is 35 micrometers. Under the same process conditions, the filament breakage frequency using an eight-roller low-friction damage printing nozzle structure is reduced to an average of 4 hours / time, and the surface roughness Ra of the sample surface is reduced to 28 micrometers due to the uniform clamping force of the rollers 24. Furthermore, by adding powdered carbonyl iron as a hybrid filler to the storage cavity 31 of the eight-roller novel printing nozzle, a 3D printed glass fiber reinforced nylon composite material with microwave absorption properties can be prepared.

[0052] like Figure 6 and Figure 7 As shown, the rolling block 22 can also be a spherical ball bearing 25. The mounting frame 21 is decagonal, and a through hole is formed on the ball bearing 25, passing through the center of the ball bearing 25. The through hole is used to mount the shaft 23, which passes through it to achieve the rotation of the roller 24. To adapt to the specifications of commonly used 3D printing filaments 4, the diameter of the spherical ball bearing 25 ranges from 0.2 to 1.4 mm. In a specific embodiment, the surface roughness Ra of the ball bearing 25 is ≤1.6 μm, the diameter of the ball bearing 25 is 0.73 mm, the diameter of the through hole is 0.2 mm, and the side length of the mounting frame 21 is 0.75 mm. The nozzle structure of this embodiment can match the 3D printing manufacturing needs of commonly available 1K or 3K type continuous fiber filaments 4. Taking the 3D printing of 1K continuous carbon fiber reinforced polyaryletherketone filament with a diameter of 0.4 mm as an example, the average filament breakage frequency using a traditional nozzle structure is 0.5 hours / time, and the surface roughness Ra of the printed sample is 32 micrometers. However, under the same process conditions, the filament breakage frequency using a ten-ball bearing low-friction damage printing nozzle structure is reduced to an average of 3 hours / time, and the surface roughness Ra of the sample is reduced to 22 micrometers. Furthermore, by adding carbon nanotube slurry as a hybrid filler to the filler storage cavity 31 of the ten-ball bearing novel printing nozzle, a 3D printed carbon fiber reinforced polyaryletherketone composite material with high thermal conductivity can be prepared.

[0053] The novel printing nozzle of this application is of great value in optimizing the forming effect of continuous fiber 3D printed parts, controlling the defect content of parts, improving the mechanical properties of parts, and realizing the preparation of functional composite materials. It can effectively support the improvement of the stability and economy of 3D printing process and promote the advancement of the maturity of continuous fiber 3D printing technology.

[0054] This application embodiment also provides a continuous fiber 3D printed composite material product. The continuous fiber 3D printed composite material product is printed using a 3D printing device with the above-mentioned continuous fiber 3D printing nozzle structure. The storage cavity 31 stores filler, and during the printing process, the filler delivery assembly delivers the filler from the storage cavity 31 to the outer surface of the rolling block 22.

[0055] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A continuous fiber 3D printing nozzle structure, characterized in that, It includes a hollow cylindrical nozzle (1), a rolling device (2) and a housing (3). The central through hole inside the hollow cylindrical nozzle (1) serves as the filament outlet (11) through which the printing raw material passes. The rolling device (2) is located at the front end of the hollow cylindrical nozzle (1). The housing (3) surrounds the outer periphery of the hollow cylindrical nozzle (1). The inner wall of the housing (3) and the outer wall of the hollow cylindrical nozzle (1) form a storage cavity (31) for storing filler. The rolling device (2) includes a regular polygonal mounting frame (21) and rolling blocks (22). Each side of the regular polygonal mounting frame (21) serves as a mounting axis (23). A rolling block (22) is rotatably mounted on each mounting axis (23) of the mounting frame (21). The axis of rotation of the rolling block (22) is coaxial with the mounting axis (23) where the rolling block (22) is located. The cross section of the rolling block (22) in the direction perpendicular to the axis of the mounting axis (23) is circular. The raw material extruded from the hollow cylindrical nozzle (1) passes through the space enclosed by multiple rolling blocks (22). During the movement of the 3D printing nozzle, at least one rolling block (22) presses firmly onto the surface of the extruded filament (4). The bottom wall of the outer shell (3) is provided with a filler conveying assembly, which is used to convey the filler of the storage cavity (31) to the outer surface of the rolling block (22).

2. The continuous fiber 3D printing nozzle structure according to claim 1, characterized in that, The packing conveying assembly includes a packing supply chamber (32) corresponding to the rolling block (22) in one by one. The bottom of the packing supply chamber (32) is provided with a discharge port (33). The edge of the discharge port (33) is engaged with the outer surface of the rolling block (22). The top of the packing supply chamber (32) is connected to the bottom of the storage chamber (31). The bottom of the packing supply chamber (32) or the storage chamber (31) is provided with an opening and closing assembly (34) for controlling the connection or closing of the packing supply chamber (32) and the storage chamber (31).

3. The continuous fiber 3D printing nozzle structure according to claim 2, characterized in that, The opening and closing assembly (34) includes a movable plate. The filler supply chamber (32) is provided with a groove in the radial direction of the wire outlet hole (11). The filler supply chamber (32) has an opening on the side facing away from the axis of the hollow columnar nozzle (1). The movable plate passes through the opening and is inserted into the groove. The movable plate slides in the groove in the radial direction of the wire outlet hole (11).

4. The continuous fiber 3D printing nozzle structure according to claim 1, characterized in that, The mounting bracket (21) is in the shape of a regular octagon or a regular decagon.

5. The continuous fiber 3D printing nozzle structure according to claim 1, characterized in that, The rolling block (22) is a roller (24) or a ball (25).

6. The continuous fiber 3D printing nozzle structure according to claim 1, characterized in that, The rolling block (22) has a thermal conductivity greater than or equal to 250. Metallic materials, among which, Watts per meter per Kelvin is a unit of thermal conductivity.

7. The continuous fiber 3D printing nozzle structure according to claim 1, characterized in that, The outer periphery of the rolling block (22) is coated with a coating having a thermal conductivity greater than or equal to 250. Metallic materials, among which, Watts per meter per Kelvin is a unit of thermal conductivity.

8. The continuous fiber 3D printing nozzle structure according to claim 1, characterized in that, The surface roughness Ra of the rolling block (22) is ≤1.6μm.

9. The continuous fiber 3D printing nozzle structure according to claim 1, characterized in that, The mounting bracket (21) is made of a self-lubricating material or the surface of the mounting bracket (21) is provided with a self-lubricating material.

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