Continuous fiber reinforced resin-based composite 3D printing end and printing method

Abstract

The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The application discloses a continuous fiber reinforced resin-based composite 3D printing terminal and a printing method. The

Description

Technical Field

[0001] This invention belongs to the field of 3D printing technology for fiber-reinforced composite materials, specifically relating to a 3D printing end of a continuous fiber-reinforced resin-based composite material and a printing method thereof. Background Technology

[0002] Fiber-reinforced composite materials, due to their lightweight, high strength, and fatigue resistance, have been widely used as a new generation of structural materials in fields such as biomedicine and aerospace. 3D printing technology has enabled the low-cost and rapid fabrication of continuous fiber-reinforced composite materials, and has become an important means of processing complex and irregularly shaped components, with broad application prospects.

[0003] Currently, continuous fiber reinforced composite material 3D printing is mainly based on fused deposition modeling (FDM) technology. Depending on the raw material processing and structural form, it can be divided into two main categories: one is the "double extrusion" process, the principle of which can be found in [link to relevant documentation]. Figure 1 In this "dual extrusion" process, pre-impregnated continuous fibers and a resin matrix are fed into separate printheads. The continuous fibers are then directly embedded between the resin layers through two nozzles. Depositing the resin matrix separately in this process can improve the surface quality of the specimen and, to some extent, reduce the porosity caused by the minimum bending radius of the fibers. However, the "dual extrusion" process only embeds continuous fibers between the resin layers, with the continuous fibers acting as interlayer reinforcement. Since the resin layers themselves do not contain continuous fibers, the strength of the manufactured part is limited, resulting in poor mechanical properties.

[0004] Another type is the "co-extrusion" process, in which polymer filaments and continuous fibers are fed into the FDM hot melt chamber. The polymer filaments are heated and impregnated with the continuous fibers, then extruded from the nozzle, completing the printing process according to a pre-planned path, thus integrating composite material preparation and forming. The advantage of this forming process is its simple flow and rapid forming capability. Existing "co-extrusion" processes simply impregnate the resin and continuous fibers in the hot melt chamber before directly extruding them onto the forming platform. Only a layer of resin is wrapped around the outside of the continuous fibers, without the resin penetrating into the interior. Due to insufficient wetting of the molten resin and continuous fibers, numerous defects such as pores and interlayer voids are generated inside the part. Simultaneously, during the printing process, the fiber bonding force at bends is weak, making the fibers prone to breakage, resulting in poor forming quality, and the strength of the part failing to meet the design expectations, or even leading to printing failure. The disadvantages of the "co-extrusion" process are particularly pronounced under high-viscosity resin and rapid printing conditions, as it is difficult for the fiber bundle to be fully impregnated by the molten resin, resulting in mechanical properties of the part significantly lower than theoretical values. Furthermore, the co-extrusion process cannot embed continuous fibers between resin layers, resulting in low fiber content in the parts and making it impossible to meet mechanical property requirements.

[0005] In summary, this invention proposes a 3D printing end and printing method for continuous fiber reinforced resin matrix composites, which improves the blending method of fibers and resins and the fiber placement method, so that continuous fibers are contained in both the interior and interlayer of the resin layer, thereby improving the strength and mechanical properties of the part. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the technical problem this invention aims to solve is to provide a 3D printing end of a continuous fiber-reinforced resin matrix composite material and a printing method thereof.

[0007] The present invention solves the aforementioned technical problem by adopting the following technical solution:

[0008] A 3D printing end of a continuous fiber-reinforced resin matrix composite material includes an end platform, a first barrel, a blending nozzle, a second barrel, a second fiber nozzle, and an inductor coil; characterized in that the printing end also includes a pressure screw;

[0009] The first barrel is installed at the lower part of the end platform. The inner cavity of the first barrel is a melt-blending chamber. A blending nozzle is installed at the lower end of the first barrel. An inductor coil is wrapped around the outer wall of the first barrel. Polymer filaments are melted in the upper part of the melt-blending chamber to obtain molten resin. A pressure screw is rotatably installed inside the first barrel. The rotation of the pressure screw transports the molten resin to the middle of the melt-blending chamber. Continuous fibers pass through the through hole in the center of the pressure screw. When passing through the middle of the melt-blending chamber, they are pressurized and blended with the molten resin, so that the outer surface of the continuous fibers is coated with a layer of resin while the molten resin impregnates the interior of the continuous fibers. Finally, they are extruded from the blending nozzle. The second barrel is installed at the lower part of the end platform. A second fiber nozzle is installed at the lower end of the second barrel. An inductor coil is wrapped around the outer wall of the second barrel. Other continuous fibers are heated inside the second barrel and then extruded from the second fiber nozzle.

[0010] Furthermore, the melt blending chamber is divided into a heating section, a pressurizing section, and an extrusion section from top to bottom. The diameter of the heating section is larger than that of the extrusion section, and the diameter of the pressurizing section gradually decreases from the same diameter as the heating section to the same diameter as the extrusion section.

[0011] The pressurized screw includes a screw body, a first threaded post, a connecting post, and a second threaded post. The screw body is rotatably connected to the first barrel. The first threaded post is installed at the lower end of the screw body and is located in the lower part of the heating section of the melt blending chamber. The second threaded post is located below the first threaded post and is connected to the first threaded post through the connecting post. The second threaded post is located in the upper part of the extrusion section of the melt blending chamber, and the molten resin can flow through the thread grooves of the first and second threaded posts.

[0012] Furthermore, the pitch of the first threaded post is greater than the pitch of the second threaded post.

[0013] Furthermore, the printing end also includes a feeding mechanism; the feeding mechanism includes a stepper motor, a pinion, a large gear, a synchronous belt, a synchronous pulley, a pressure plate, a pressure spring, a roller belt, rollers, and a gearbox; the gearbox is installed on the upper part of the end platform, the stepper motor is installed on the side of the gearbox, the pinion is located on the output shaft of the stepper motor, the large gear is installed in the gearbox through a connecting shaft, and the large gear meshes with the pinion; one synchronous pulley is coaxially installed with the large gear, and the other synchronous pulley is installed in the gearbox through another connecting shaft, and the synchronous belt is fitted on the two synchronous pulleys; one end of the pressure spring is embedded in the upper end of the pressure plate, and the other end is connected to the gearbox, and the lower end of the pressure plate is rotatably connected to the gearbox; two rollers are installed at intervals on the side of the pressure plate, and the roller belt is fitted on the two rollers.

[0014] Furthermore, the printing end also includes a filament cutting mechanism; the filament cutting mechanism includes a clamping plate, a first U-shaped cutter, an electric push rod, and a second U-shaped cutter; the clamping plate is clamped at the lower part of the blending nozzle and the second fiber nozzle, the first U-shaped cutter and the second U-shaped cutter are rotatably connected to the clamping plate respectively, two electric push rods are connected to the clamping plate, the telescopic end of one electric push rod is connected to the first U-shaped cutter, and the telescopic end of the other electric push rod is connected to the second U-shaped cutter.

[0015] Furthermore, the first material cylinder is equipped with an overflow valve, and a temperature sensor is installed on the outer wall of the first material cylinder.

[0016] A method for 3D printing continuous fiber-reinforced resin matrix composites includes the following:

[0017] Polymer filaments are fed to the upper part of the melt blending chamber of the first barrel and melted under the heating of the inductor coil to obtain molten resin; the rotating pressure screw conveys the molten resin to the middle of the melt blending chamber; continuous fibers pass through the through hole of the pressure screw, and are pressurized and blended with the molten resin when passing through the middle of the melt blending chamber, and then extruded from the blending nozzle to form a blended layer;

[0018] The second fiber is fed into the second barrel for heating and then extruded from the second fiber nozzle. During the printing process, the blending nozzle and the second fiber nozzle move along the same path, with the second fiber nozzle located behind the blending nozzle. The other continuous fibers are extruded from the second fiber nozzle and laid on the blend layer. When the blending nozzle and the second fiber nozzle detach from the printing substrate, the two continuous fibers are cut off, completing the 3D printing of the continuous fiber reinforced composite material and obtaining the printed component.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. To address the problems of low fiber content in existing thermoplastic resin-based composite 3D printing, which makes it difficult to effectively wet continuous fibers, resulting in low fiber-resin matrix bonding strength, poor mechanical properties of printed components, weak fiber bonding at bends, and easy breakage, this invention improves the fiber-resin blending method and fiber placement method. A pressure screw is used to transport molten resin from the heating section of the melt blending chamber to the pressure section. This pressure blending method achieves blending of continuous fibers and molten resin, not only coating the outside of the continuous fibers with a layer of resin but also filling the interior of the continuous fibers. This improves the wetting degree between the continuous fibers and molten resin, reduces the porosity inside the continuous fibers, avoids defects such as numerous air bubbles inside the printed components, and improves surface quality and the mechanical properties of the components.

[0021] 2. The rotating screw drives the molten resin to rotate, causing the continuous fibers to form a tight spiral wound, which improves the load-bearing capacity of the printed component. The molten resin is evenly distributed throughout the continuous fibers, improving the mechanical properties of the printed component. Not only do the blended layers contain continuous fibers, but they are also laid between adjacent blended layers as interlayer reinforcement fibers, improving the interfacial bonding between the fibers and resin and increasing the overall fiber content of the product. The placement of continuous fibers between blended layers can be controlled according to the printing requirements, i.e., the ratio of fiber layer to resin layer thickness. In summary, this invention enables 3D printing of continuous fiber reinforced thermoplastic matrix composite components with high mechanical properties, high forming efficiency, and good surface quality, making it suitable for forming complex components with high performance requirements. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the forming principle of a traditional dual extrusion process.

[0023] Figure 2 This is a schematic diagram illustrating the forming principle of the present invention;

[0024] Figure 3 This is an overall structural diagram of the present invention;

[0025] Figure 4 This is a sectional view of the overall structure;

[0026] Figure 5 This is a longitudinal sectional view of the first barrel;

[0027] Figure 6 Here is a structural diagram of the pressure screw;

[0028] Figure 7 Here is a structural diagram of the feeding mechanism;

[0029] Figure 8 This is a structural diagram of the wire shearing mechanism;

[0030] In the diagram, 1. First fiber; 2. Feeding mechanism; 3. End platform; 4. Polymer filament; 5. First barrel; 6. Blending nozzle; 7. Second barrel; 8. Second fiber nozzle; 9. Second fiber; 10. Inductor coil; 11. Pressure screw; 12. Screw drive mechanism; 13. Fiber shearing mechanism; 14. Overflow valve; 15. Temperature sensor;

[0031] 2-1 Stepper motor; 2-2 Pinion; 2-3 Large gear; 2-4 Synchronous belt; 2-5 Synchronous pulley; 2-6 Pressure plate; 2-7 Pressure spring; 2-8 Roller belt; 2-9 Roller; 2-10 Gearbox; 5-1 Heating section; 5-2 Pressurizing section; 5-3 Extrusion section; 11-1 Screw body; 11-2 First threaded post; 11-3 Connecting post; 11-4 Second threaded post; 12-1 Motor; 12-2 Driving gear; 12-3 Driven gear; 13-1 Clamping plate; 13-2 First U-shaped cutter; 13-3 Moving push rod; 13-4 Second U-shaped cutter. Detailed Implementation

[0032] Specific embodiments are given below with reference to the accompanying drawings. These specific embodiments are only used to illustrate the technical solutions of the present invention in detail, and are not intended to limit the scope of protection of this application.

[0033] This invention relates to a 3D printing end of a continuous fiber-reinforced resin matrix composite material (hereinafter referred to as the printing end, see [link]). Figures 3-8 The system includes an end platform 3, a first material cylinder 5, a blending nozzle 6, a second material cylinder 7, a second fiber nozzle 8, an inductor coil 10, and a pressure screw 11.

[0034] The inner cavity of the first barrel 5 is a melt blending cavity. The melt blending cavity is divided into a heating section 5-1, a pressurizing section 5-2 and an extrusion section 5-3 from top to bottom. The diameter of the heating section 5-1 is larger than the diameter of the extrusion section 5-3. The diameter of the pressurizing section 5-2 gradually decreases from the same diameter as the heating section 5-1 to the same diameter as the extrusion section 5-3.

[0035] The first barrel 5 is fixedly installed at the lower part of the end platform 3. The blending nozzle 6 is installed at the discharge port at the lower end of the first barrel 5. An inductor coil 10 is wrapped around the outer wall of the first barrel 5. The polymer filament 4 is conveyed to the heating section 5-1 of the melt blending chamber. The polymer filament 4 is heated to melt by the inductor coil 10 to obtain molten resin. The pressure screw 11 is rotatably installed inside the first barrel 5. The first fiber 1 passes through the through hole in the center of the pressure screw 11. The rotation of the pressure screw 11 conveys the molten resin in the heating section 5-1 of the melt blending chamber to the pressure section 5-2. As the diameter of the pressure section 5-2 gradually decreases, a pressure difference is generated, which increases the pressure in the pressure section 5-2. The first fiber 1 passes through the pressure section 5-2. At step 2, the first fiber 1 is pressurized and blended with molten resin. The blended first fiber 1 is extruded from the blending nozzle 12. Pressurized blending not only coats the outer wall of the first fiber 1 with a layer of resin, but also forces the molten resin into the interior of the first fiber 1 under pressure. The molten resin is evenly distributed throughout the interior of the first fiber 1, which enhances the wetting ability between the first fiber 1 and the molten resin and increases the strength of the printed component. The second barrel 7 is also fixedly installed at the lower part of the end platform 3. The lower end of the second barrel 7 is equipped with the second fiber nozzle 8. An inductor coil 10 for heating the second fiber is installed on the outer wall of the second barrel 7. The second fiber 9 is transported into the second barrel 7, heated in the second barrel 7, and then extruded from the second fiber nozzle 8.

[0036] The pressurizing screw 11 includes a screw body 11-1, a first threaded post 11-2, a connecting post 11-3, and a second threaded post 11-4. The screw body 11-1, the first threaded post 11-2, and the second threaded post 11-4 all have through holes at their centers for the passage of the first fiber 1. The pitch of the first threaded post 11-2 is greater than that of the second threaded post 11-4, which helps to increase the pressure within the pressurizing section 5-2. The middle part of the screw body 11-1 is rotatably connected to the upper end of the first barrel 5 via a bearing, and a gasket and sealing washer achieve a sealed connection between the pressurizing screw 11 and the first barrel 5. The upper end of the screw body 11-1 extends out of the first barrel 5 and is connected to the screw drive mechanism 12, which drives the rotation of the pressurizing screw 11. The first threaded post 11-2 is fixedly installed at the lower end of the screw body 11-1 and located in the heating section of the melt blending chamber. In the lower part of 5-1, the outer diameter of the first threaded post 11-2 is slightly smaller than the inner diameter of the heating section 5-1 of the melt blending chamber, so that the molten resin in the heating section 5-1 flows through the thread groove of the first threaded post 11-2 and enters the pressurizing section 5-2; the second threaded post 11-4 is located below the first threaded post 11-2 and is connected to the first threaded post 11-2 through multiple connecting posts 11-3. The connecting posts 11-3 are located in the pressurizing section 5-2 of the melt blending chamber and the multiple connecting posts 11-3 are staggered to form a hollow between adjacent connecting posts 11-3, so that the molten resin can fully contact the first fiber 1. The second threaded post 11-4 is located in the upper part of the extrusion section 5-3 of the melt blending chamber, and the outer diameter of the second threaded post 11-4 is slightly smaller than the inner diameter of the extrusion section 5-3, so that the molten resin in the pressurizing section 5-2 can flow through the thread groove of the second threaded post 11-4 and enter the extrusion section 5-3.

[0037] Furthermore, the screw drive mechanism 12 includes a motor 12-1, a drive gear 12-2, and a driven gear 12-3; the motor 12-1 is fixedly mounted on the upper part of the end platform 3, the drive gear 12-2 is fixed on the output shaft of the motor 12-1, and the driven gear 12-3 is fixed on the upper part of the screw body 11-1, and the driven gear 12-3 is axially limited by a sleeve and a nut, and the driven gear 12-3 meshes with the drive gear 12-3; the motor 12-1 drives the drive gear 12-2 to rotate, which in turn drives the driven gear 12-3 to rotate, thereby driving the pressure screw 11 to rotate inside the first barrel 5.

[0038] The first fiber 1, polymer filament 4, and second fiber 9 are conveyed by a feeding mechanism 2. The feeding mechanism 2 includes a stepper motor 2-1, a pinion 2-2, a large gear 2-3, a synchronous belt 2-4, a synchronous pulley 2-5, a pressure plate 2-6, a pressure spring 2-7, a roller belt 2-8, a roller 2-9, and a gearbox 2-10. The gearbox 2-10 is installed on the upper part of the end platform 3, the stepper motor 2-1 is installed on the side of the gearbox 2-10, the pinion 2-2 is fixed on the output shaft of the stepper motor 2-1, the large gear 2-3 is installed in the gearbox 2-10 through a connecting shaft, and the large gear 2-3 meshes with the pinion 2-2. One synchronous pulley 2-5 is coaxially installed with the large gear 2-3, and another synchronous pulley 2-5 is installed in the gearbox 2-10 through another connecting shaft. The synchronous belt 2-4 is fitted onto the two synchronous pulleys 2-10. 5. One end of the clamping spring 2-7 is embedded in the upper end of the clamping plate 2-6, and the other end is connected to the gearbox 2-10. The lower end of the clamping plate 2-6 is rotatably connected to the gearbox 2-10. Two rollers 2-9 are installed at intervals on the side of the clamping plate 2-6, and the roller belt 2-8 is fitted on the two rollers 2-9. The stepper motor 2-1 drives the small gear 2-2 to rotate, and the large gear 2-3 rotates synchronously with the small gear 2-2, causing the synchronous belt 2-4 to rotate. The clamping spring 2-7 pushes the clamping plate 2-6 to make the roller belt 2-8 and the synchronous belt 2-4 in close contact. When the synchronous belt 2-4 rotates, it drives the roller belt 2-8 to rotate together. The first fiber 1, polymer filament 4 or the second fiber 9 is sandwiched between the synchronous belt 2-4 and the roller belt 2-8, and is conveyed under the action of the synchronous belt 2-4 and the roller belt 2-8. The feeding speed can be controlled by controlling the speed of the stepper motor 2-1.

[0039] Furthermore, the printing end also includes a filament cutting mechanism 13; the filament cutting mechanism 13 includes a clamping plate 13-1, a first U-shaped cutter 13-2, an electric push rod 13-3, and a second U-shaped cutter 13-4; the clamping plate 13-1 is clamped at the lower part of the blending nozzle 6 and the second fiber nozzle 8, the first U-shaped cutter 13-2 and the second U-shaped cutter 13-4 are respectively rotatably connected to the clamping plate 13-1, the two electric push rods 13-3 are connected to the clamping plate 13-1, the telescopic end of one electric push rod 13-3 is connected to the first U-shaped cutter 13-2, and is used to realize the reciprocating swing of the first U-shaped cutter 13-2, thereby cutting the first fiber 1 and cutting it; the telescopic end of the other electric push rod 13-3 is connected to the second U-shaped cutter 13-4, and is used to realize the reciprocating swing of the second U-shaped cutter 13-4, thereby cutting the second fiber 9 and cutting it.

[0040] Furthermore, an overflow valve 14 is provided on the lower side of the first barrel 5. The overflow valve 14 has two pipes, one connected to the heating section of the melt blending chamber and the other connected to the extrusion section of the melt blending chamber. The overflow valve 14 can control the overflow pressure by adjusting the tightness of the top nut, and can also limit the pressure of the pressurization section and the overflow backflow in case of overpressure. A temperature sensor 15 is also installed on the outer wall of the first barrel 5 to measure the temperature in the melt blending chamber. The current of the inductor coil 10 is adjusted according to the temperature measured by the temperature sensor 15 to make the temperature in the melt blending chamber reach the melting point of the polymer filament and maintain a constant temperature in the melt blending chamber. The first fiber 1 and the second fiber 9 are both continuous fibers, and they can be the same type of fiber or different types of fiber. During the printing process, the blending nozzle 6 and the second fiber nozzle 8 move along the same path, and the second fiber nozzle 8 is located behind the blending nozzle 6, printing the second fiber 9 on top of the blended layer.

[0041] A method for 3D printing continuous fiber-reinforced resin matrix composites includes the following:

[0042] Connect the printing end to the 3D printer or robotic arm via a connecting flange, and load the first fiber 1, polymer filament 4 and the second fiber 9, and turn on the power to the inductor coil 10 and the temperature sensor 15.

[0043] The polymer filament 4 is conveyed to the heating section 5-1 of the melting and blending chamber of the first barrel 5 under the action of the corresponding feeding mechanism 2 and melted under the heating of the inductor coil 10 to obtain molten resin; the pressure screw 11 rotates to convey the molten resin in the heating section 5-1 of the melting and blending chamber to the pressure section 5-2; the first fiber 1 passes through the through hole of the pressure screw 11 and through the pressure section 5-2 of the melting and blending chamber under the action of the corresponding feeding mechanism 2, and is pressurized and blended with the molten resin in the pressure section 5-2; the blended first fiber 1 is extruded from the blending nozzle 6 to form a blended layer;

[0044] Meanwhile, the second fiber 9 enters the second barrel 7 under the action of the corresponding feeding mechanism 2, is heated under the action of the inductor coil 10, and is finally extruded by the second fiber nozzle 8. Since the blending nozzle 6 and the second fiber nozzle 8 move along the same path during the printing process, and the second fiber nozzle 8 is located behind the blending nozzle 6, the second fiber 9 is extruded from the second fiber nozzle 8 and laid on the blended layer. Therefore, the second fiber acts as an interlayer reinforcing fiber of the blended layer, which improves the strength and mechanical properties of the printed component. For the forming principle, see [link to relevant documentation]. Figure 2 When the blending nozzle 6 and the second fiber nozzle 8 detach from the printing substrate, the first fiber 1 and the second fiber 9 are cut by the fiber shearing mechanism 13 to complete the 3D printing of the continuous fiber reinforced composite material and obtain the printed component.

[0045] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A 3D printing end of a continuous fiber-reinforced resin matrix composite material, comprising an end platform, a first barrel, a blending nozzle, a second barrel, a second fiber nozzle, and an inductor coil; characterized in that, The printing end also includes a pressure screw; The first barrel is installed at the lower part of the end platform. The inner cavity of the first barrel is a melt-blending chamber, which is divided into a heating section, a pressurizing section, and an extrusion section from top to bottom. The diameter of the heating section is larger than that of the extrusion section, and the diameter of the pressurizing section gradually decreases from the same diameter as the heating section to the same diameter as the extrusion section. A blending nozzle is installed at the lower end of the first barrel. An inductor coil is wrapped around the outer wall of the first barrel. The polymer filament melts in the heating section of the melt-blending chamber to obtain molten resin. A pressurizing screw is rotatably installed inside the first barrel. The rotation of the pressurizing screw is used to melt the resin. The molten resin is conveyed to the pressurized section of the melt blending chamber. The continuous fiber passes through the through hole in the center of the pressurized screw. When passing through the pressurized section of the melt blending chamber, it is pressurized and blended with the molten resin, so that the continuous fiber is coated with a layer of resin while the molten resin is impregnated into the continuous fiber. Finally, it is extruded from the blending nozzle. The second barrel is installed at the lower part of the end platform, and the second fiber nozzle is installed at the lower end of the second barrel. The outer wall of the second barrel is surrounded by an inductor coil. The other continuous fibers are heated in the second barrel and then extruded from the second fiber nozzle. The pressurized screw includes a screw body, a first threaded post, a connecting post, and a second threaded post. The screw body is rotatably connected to the first barrel. The first threaded post is installed at the lower end of the screw body and is located in the lower part of the heating section of the melt blending chamber. The second threaded post is located below the first threaded post and is connected to the first threaded post through the connecting post. The connecting post is located in the pressurized section of the melt blending chamber, and multiple connecting posts are arranged alternately, forming a hollow between adjacent connecting posts. The second threaded post is located in the upper part of the extrusion section of the melt blending chamber, and molten resin can flow through the threaded grooves of the first and second threaded posts.

2. The 3D printing end of the continuous fiber-reinforced resin matrix composite material according to claim 1, characterized in that, The pitch of the first threaded post is greater than the pitch of the second threaded post.

3. The 3D printing end of the continuous fiber-reinforced resin matrix composite material according to claim 1, characterized in that, The printing end also includes a feeding mechanism; the feeding mechanism includes a stepper motor, a pinion, a gear, a synchronous belt, a synchronous pulley, a pressure plate, a pressure spring, a roller belt, rollers, and a gearbox; the gearbox is installed on the upper part of the end platform, the stepper motor is installed on the side of the gearbox, the pinion is located on the output shaft of the stepper motor, the gear is installed in the gearbox through a connecting shaft, and the gear meshes with the pinion; one synchronous pulley is coaxially installed with the gear, and the other synchronous pulley is installed in the gearbox through another connecting shaft, and the synchronous belt is fitted on the two synchronous pulleys; one end of the pressure spring is embedded in the upper end of the pressure plate, and the other end is connected to the gearbox, and the lower end of the pressure plate is rotatably connected to the gearbox; two rollers are installed at intervals on the side of the pressure plate, and the roller belt is fitted on the two rollers.

4. The 3D printing end of the continuous fiber-reinforced resin matrix composite material according to claim 1 or 3, characterized in that, The printing end also includes a filament cutting mechanism; the filament cutting mechanism includes a clamping plate, a first U-shaped cutter, an electric push rod, and a second U-shaped cutter; the clamping plate is clamped at the lower part of the blending nozzle and the second fiber nozzle, the first U-shaped cutter and the second U-shaped cutter are rotatably connected to the clamping plate respectively, two electric push rods are connected to the clamping plate, the telescopic end of one electric push rod is connected to the first U-shaped cutter, and the telescopic end of the other electric push rod is connected to the second U-shaped cutter.

5. The 3D printing end of the continuous fiber-reinforced resin matrix composite material according to claim 1, characterized in that, The first material cylinder is equipped with an overflow valve, and a temperature sensor is installed on the outer wall of the first material cylinder.

6. A method for 3D printing continuous fiber-reinforced resin matrix composites, wherein the method uses the printing end as described in claim 1; characterized in that, Includes the following: Polymer filaments are fed to the upper part of the melt blending chamber of the first barrel and melted under the heating of the inductor coil to obtain molten resin; the rotating pressure screw conveys the molten resin to the middle of the melt blending chamber; continuous fibers pass through the through hole of the pressure screw, and are pressurized and blended with the molten resin when passing through the middle of the melt blending chamber, and then extruded from the blending nozzle to form a blended layer; The second fiber is fed into the second barrel for heating, and then extruded from the second fiber nozzle; During the printing process, the blending nozzle and the second fiber nozzle move along the same path, with the second fiber nozzle located behind the blending nozzle. The other continuous fibers are extruded from the second fiber nozzle and laid on the blend layer. When the blending nozzle and the second fiber nozzle detach from the printing substrate, the two continuous fibers are cut off, completing the 3D printing of the continuous fiber reinforced composite material and obtaining the printed component.

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