A resin and continuous fiber bonded composite additive manufacturing system

Abstract

This invention discloses a composite additive manufacturing system and method combining resin and continuous fibers, aiming to solve the technical problems of easy fiber breakage, springback, slow nozzle switching, and weak fiber-resin bonding in traditional composite additive manufacturing. The system includes an inverted T-shaped bracket, a first slide, a second slide, a resin extrusion device, a continuous fiber extrusion device, and a filament cutting mechanism. The first and second slides, vertically mounted on the inverted T-shaped bracket, can move synchronously in opposite directions, enabling rapid switching between dual nozzles. The continuous fiber extrusion device is equipped with an elastic pressure regulating structure and a filament reverse check mechanism, using a passive traction method to output continuous fiber filaments. The filament cutting mechanism uses a first and second micro linear slide to drive pneumatic shears for precise filament cutting. This invention, through structural optimization, improves printing efficiency and stability, enhances the mechanical properties of printed components, and achieves equipment safety protection, making it suitable for 3D printing high-performance load-bearing components.

Description

Technical Field

[0001] This invention relates to a composite additive manufacturing system combining resin and continuous fibers, belonging to the field of additive manufacturing technology. Background Technology

[0002] Currently, FDM 3D printing technology has been widely used. Among them, resin materials are the most widely used. However, the mechanical properties of this material are very limited. For example, the tensile strength of ABS material is about 40-55 MPa, and the tensile strength of PLA material is about 50-70 MPa. Moreover, the heat distortion temperature is low, and it is easy to soften and deform in high-temperature environments. It is difficult to use it in some load-bearing components in manufacturing and aerospace fields, and its application scenarios are very limited.

[0003] Continuous fiber materials have high specific strength and specific stiffness, even exceeding most metal materials. Traditional continuous fiber composite molding mostly requires the use of molds, which is not only complex and costly, but also limits the complexity of the molded parts. In contrast, carbon fiber 3D printing has unparalleled advantages. Adding continuous fiber materials to the traditional FDM printing process can greatly improve the mechanical properties of the workpiece. However, current continuous fiber 3D printing has problems such as weak bonding between fiber and resin interface, easy fiber breakage during continuous fiber printing, and unstable printing.

[0004] To address the above-mentioned technical challenges, this invention designs a composite additive manufacturing system that combines ordinary resin and continuous fiber, thus solving the technical difficulties of composite 3D printing of two different materials. Summary of the Invention

[0005] Purpose of the invention: In view of the above-mentioned prior art, a composite additive manufacturing system combining resin and continuous fiber is proposed to solve the defects of weak mechanical properties of ordinary resin 3D printed components, and at the same time solve the problems of filament breakage, roughness and springback that are prone to occur in the continuous fiber 3D printing process.

[0006] Technical solution: A composite additive manufacturing system combining resin and continuous fiber, comprising: an inverted T-shaped bracket, a first slide, a second slide, a T-shaped connecting plate, a resin extrusion device, a continuous fiber extrusion device, and a fiber cutting mechanism;

[0007] The inverted T-shaped bracket has a first slide table vertically installed on the left side, a second slide table vertically installed on the right side, and a T-shaped connecting plate fixedly installed in the lower middle part.

[0008] The slider of the first slide is fixed to the resin extrusion device via a resin extrusion machine connector, and the slider of the second slide is fixed to the continuous fiber extrusion device via a continuous fiber extrusion machine connector. The first slide and the second slide can move synchronously in opposite directions to achieve rapid switching between the nozzles of the resin extrusion device and the continuous fiber extrusion device.

[0009] The fiber cutting mechanism is installed below the T-shaped connecting plate. After the fiber layer printing is completed, the pneumatic scissors of the fiber cutting mechanism can move to the nozzle of the continuous fiber extrusion device to complete the fiber cutting.

[0010] The continuous fiber extrusion device is equipped with a filament reverse check mechanism and outputs continuous fiber filaments in a passive traction manner.

[0011] Furthermore, the continuous fiber extrusion device includes a filament reverse check mechanism located at the upper part and a fiber filament output mechanism located at the lower part;

[0012] The reverse check mechanism for the filament includes a first pressure plate and a second pressure plate arranged in parallel with each other. The inner surface of the first pressure plate is covered with pure cotton cloth, and the inner surface of the second pressure plate is arranged with a number of protruding structures at intervals from top to bottom. The front end of each protruding structure is an inclined surface facing downwards from the first pressure plate, and a silicone sheet with its leading edge protruding towards the first pressure plate is connected to the inclined surface. The first pressure plate and the second pressure plate are arranged opposite to each other and connected by bolts. Continuous fiber filaments pass through the gap between the two pressure plates, and the gap can be adjusted by bolts until the silicone sheet abuts against the inner surface of the first pressure plate.

[0013] The continuous fiber filament enters from the top of the filament reverse check mechanism, exits from the bottom of the filament reverse check mechanism, and is then fed out from the nozzle at the bottom of the fiber filament output mechanism.

[0014] Furthermore, the continuous fiber extrusion device also includes a base and a vertical sliding assembly; the base consists of a lower fixed seat and an upper fixed seat, the lower fixed seat being fixedly connected to the continuous fiber extrusion machine connector; the vertical sliding assembly includes a vertical slide rail fixed to the upper fixed seat, a slider cooperating with the slide rail, and a rear connecting plate fixed to the slider; the filament reverse check mechanism is installed on the top of the rear connecting plate via a fixing frame, and the top of the rear connecting plate is also provided with a baffle to prevent the slider from overtravel; the bottom of the rear connecting plate is fixedly connected to the front connecting plate, and the fiber filament output mechanism is installed on the front side of the front connecting plate.

[0015] Furthermore, the continuous fiber extrusion device also includes an elastic pressure regulating structure; the elastic pressure regulating structure includes a vertical compression spring, a spring limiting block, a tension / compression sensor, and a horizontal support plate; the horizontal support plate is fixed to the bottom of the rear connecting plate, and the compression spring is vertically arranged between the upper seat of the fixed base and the horizontal support plate; the top of the upper seat of the fixed base is provided with a spring limiting block, the tension / compression sensor is installed on the horizontal support plate, and the compression spring is placed between the spring limiting block and the tension / compression sensor.

[0016] Furthermore, the fiber output mechanism includes a heat dissipation and heating assembly connected to the front connecting plate via a radiator fixing block; the heat dissipation and heating assembly includes a radiator, a fan, a pneumatic connector, a throat, a heating block, a heating rod, a thermocouple, and a nozzle; the fan is mounted on the radiator, and the top is connected to the pneumatic connector, with a Teflon tube inserted inside the pneumatic connector; one end of the throat is threaded to the radiator, and the other end is connected to the heating block; the heating block is fixed to the bottom of the front connecting plate by a pad, a heating rod is installed inside the heating block, a thermocouple is installed at the front end, and a nozzle is connected to the bottom; the nozzle's inner hole inlet and outlet are rounded.

[0017] Furthermore, the wire-cutting mechanism includes a first micro linear slide, a second micro linear slide, a slide transition plate, a scissor connecting block, and pneumatic scissors; the first micro linear slide is longitudinally mounted on the lower surface of the T-shaped connecting plate, and its slider is laterally mounted on the second micro linear slide through the slide transition plate; the slider of the second micro linear slide is fixed to the pneumatic scissors through the scissor connecting block.

[0018] Furthermore, the tension / compression sensor is connected to the display device via a signal line and transmits the pressure signal to the motion controller of the 3D printer;

[0019] The motion controller fine-tunes the position of the second slide in real time based on the pressure signal. When the pressure data exceeds the preset threshold, the motion controller triggers an emergency stop of the equipment.

[0020] Furthermore, the pneumatic scissors are equipped with a solenoid valve, a miniature solenoid valve controller, a pneumatic pressure regulating valve, and an air compressor;

[0021] The two air inlets of the pneumatic scissors are connected to the air outlets A and B of the solenoid valve via air pipes; the air inlet of the solenoid valve is connected to the air outlet of the pressure regulating valve, and the air inlet of the pressure regulating valve is connected to the air compressor.

[0022] A miniature solenoid valve controller is installed at the original coil of the solenoid valve. This controller is connected to the signal output port of the motion controller. The wire-cutting action is encapsulated into M commands through a custom macro program. The controller supports three working modes: single action, inching, and automatic.

[0023] Furthermore, the resin extrusion device adopts a remote filament feeding structure, including a filament feeding mechanism, a stepper motor, and a Teflon tube.

[0024] The wire feeding mechanism includes a driving wheel and a driven wheel. The driving wheel is driven by a stepper motor on the back of the connecting plate. The pneumatic connector below the wire feeding mechanism and the pneumatic connector at the top of the radiator are connected by a Teflon tube.

[0025] A composite additive manufacturing method combining resin and continuous fibers, based on the aforementioned composite additive manufacturing system, includes the following steps:

[0026] Step 1: Before printing, adjust the gap between the two pressure plates of the filament reverse check mechanism according to the diameter of the pre-impregnated continuous fiber filament, calibrate the clamping force between the fiber sheet and the pure cotton cloth, and measure and record the XYZ relative positions of the nozzles of the two extrusion devices.

[0027] Step 2: Plan and slice the workpiece, import the global print path GCode file containing print parameters, and start layered printing;

[0028] Step 3: After the resin layer is printed, the printer pauses by executing the M0 command, and the printing platform descends to the safe plane; the first slide moves the resin extrusion device upward, and the second slide moves the continuous fiber extrusion device downward in the opposite direction. The moving distance is the relative height of the two nozzles in the Z direction, thus completing the nozzle switching.

[0029] Step 4: The printing platform is reset to the printing height and the continuous fiber layer is printed. After the fiber layer printing is completed, the continuous fiber extrusion device is raised to the cutting height. The M command controls the second micro linear slide to move the pneumatic shears directly below the nozzle to complete the cutting. All components are reset.

[0030] Step 5: Repeat steps 3 to 4 until the workpiece is printed.

[0031] Beneficial effects: The composite additive manufacturing system combining resin and continuous fibers of the present invention has the following beneficial effects compared with the prior art:

[0032] 1. By setting up a reverse anti-rebound mechanism for the filament, the pure cotton cloth on the inner surface of the first pressure plate cooperates with the silicone sheet on the second pressure plate to form a reverse resistance on the continuous fiber filament, effectively counteracting the rebound force of the filament after cutting, avoiding the problem of filament pullback and scattering caused by filament breakage, ensuring the smooth delivery of the continuous fiber filament, and ensuring the continuity of the printing process.

[0033] 2. The first and second slides can move synchronously in opposite directions, which can quickly switch the nozzles of the resin extrusion device and the continuous fiber extrusion device without the need for additional complex transmission structures, simplifying the switching process, shortening the switching time, adapting to the high-efficiency requirements of layered printing, and improving the overall printing efficiency.

[0034] 3. The elastic pressure regulating structure, through the synergistic action of compression springs and tension / compression sensors, can sense the contact pressure between the nozzle and the printing surface in real time. In conjunction with the motion controller, it can finely adjust the position of the second slide to maintain stable pressure, avoid blade collision and equipment damage caused by excessive pressure, and at the same time ensure the tight bonding between continuous fibers and resin, thereby improving the mechanical properties of the printed components.

[0035] 4. The wire cutting mechanism, through the coordinated movement of the first and second micro linear slides, can drive the pneumatic scissors to move precisely to the position directly below the nozzle of the continuous fiber extrusion device to complete the wire cutting. With the M command control of the micro solenoid valve controller, the wire cutting action can be programmed and automated, adapting to different printing conditions, and supporting single-action, inching, and automatic modes, making operation flexible and convenient.

[0036] 5. The resin extrusion device adopts a remote filament feeding structure, which uses a stepper motor to drive the active wheel and the driven wheel to achieve stable conveying of resin filaments; the continuous fiber extrusion device uses a passive traction method to output filaments, and with the precise temperature control of the heat dissipation and heating components, it is suitable for the conveying and melting requirements of continuous fibers, and can also be compatible with pre-impregnated continuous fiber filaments of different specifications, thus improving the versatility of the system. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the overall assembly structure of the composite additive manufacturing system of the present invention;

[0038] Figure 2 A schematic diagram of the assembly structure of a continuous fiber extrusion device;

[0039] Figure 3 This is a schematic diagram of the second pressure plate structure;

[0040] Figure 4 This is a schematic diagram of the signal connection for the tension / compression sensor;

[0041] Figure 5 This is a schematic diagram of the pneumatic shears control system. Detailed Implementation

[0042] The invention will now be further explained with reference to the accompanying drawings.

[0043] like Figure 1 The diagram shows the overall architecture of the composite additive manufacturing system. Two L-shaped connectors 1 are fixedly connected to the printer's motion axis via their shorter plane. The longer plane of the L-shaped connector 1 is bolted to the upper part of the inverted T-shaped bracket 2 through mounting holes. A first slide 12 is installed on the left side of the inverted T-shaped bracket 2, and a second slide 3 is installed on the right side. Both slides are vertically arranged. A T-shaped connecting plate 11 is installed in the lower middle part of the inverted T-shaped bracket 2.

[0044] On the first slide 12 on the left, the slider is fixed to the resin extrusion device 36 via the resin extrusion machine connector 35. On the second slide 3 on the right, the slider is fixed to the continuous fiber extrusion device 5 via the continuous fiber extrusion machine connector 4. A 150mm miniature 28 slide 8 is longitudinally mounted on the lower surface of the T-shaped connecting plate 11, and a 100mm miniature 28 slide 6 is laterally mounted on the slider of the slide 8 via the slide 8 adapter plate 10. The slider of the slide 6 is fixed to the pneumatic shears 7 via the shear connecting block 9, which is used to cut the continuous fiber filaments.

[0045] The printing switching logic is as follows: After the resin layer printing is completed, the first slide 12 drives the ordinary resin extrusion device 36 to rise to the designated position, and the second slide 3 drives the continuous fiber extrusion device 5 to descend in the opposite direction to the printing plane, switching to fiber layer printing; after the fiber layer printing is completed, the continuous fiber extrusion device 5 is raised to the wire cutting height, and the 100mm miniature 28 slide 6 drives the pneumatic scissors 7 to move to the right to directly below the nozzle to complete the wire cutting. After all components are reset, the next printing cycle begins.

[0046] like Figure 2 As shown, the core assembly and working structure of the continuous fiber extrusion device 5 is as follows: The device consists of a base composed of a lower fixed seat 13 and an upper fixed seat 14; the lower fixed seat 13 is used to connect the continuous fiber extrusion machine connector 4. A vertical slide rail 34 is fixed on the upper fixed seat 14, and a slider 15 that can slide up and down is provided on the slide rail 34; a vertically arranged rear connecting plate 17 is fixed on the slider 15, and a baffle 16 is provided on one side of the top of the rear connecting plate 17 to prevent the slider 15 from overtraveling. The bottom of the rear connecting plate 17 is fixedly connected to the front connecting plate 18, and a vertically arranged radiator 23 is installed on the front side of the front connecting plate 18 through a radiator fixing block 21. A fan 22 for heat dissipation is installed on the radiator 23, and a pneumatic connector 20 is connected to the top of the radiator 23, into which a Teflon tube is inserted. One end of the throat tube 24 is connected to the radiator 23 via a thread, and the other end is connected to the heating block 25. The heating block 25 is fixed to the bottom of the front connecting plate 18 via a pad 27. A heating rod is installed inside the heating block 25, and a thermocouple is installed at the front end of the heating block 25 for temperature detection. A nozzle 26 is connected to the bottom of the heating block 25. The inlet and outlet of the nozzle 26 are rounded to reduce the wear of the continuous fiber filaments when passing through the nozzle. The vertical position of the nozzle 26 can be adjusted by moving the slider 15.

[0047] The continuous fiber extrusion device 5 is also equipped with an elastic pressure adjustment structure: a vertical compression spring 31 is installed between the upper seat 14 of the fixed seat and the horizontal support plate 28 at the bottom of the rear connecting plate 17; a spring limit block 30 is provided at the top of the upper seat 14 of the fixed seat, and a tension and pressure sensor 29 is installed on the horizontal support plate 28. The compression spring 31 is placed between the spring limit block 30 and the tension and pressure sensor 29, and the spring force maintains the stable pressure between the nozzle and the printing surface.

[0048] The continuous fiber extrusion device 5 also includes a filament reverse check mechanism: This mechanism is installed on the top of the rear connecting plate 17 and consists of a fixing frame 19, a first pressure plate 33, and a second pressure plate 32. The fixing frame 19 is fastened to the rear connecting plate 17, and the first pressure plate 33 and the second pressure plate 32 are positioned opposite each other. The inner surface of the first pressure plate 33 is covered with pure cotton cloth to improve its roughness. Figure 3 As shown, on the inner surface of the second pressure plate 32, a raised structure 321 with a rectangular inclined surface at the front end is arranged every 12 mm from top to bottom. The inclined surface is at a 45° downward angle, and a silicone sheet 322 with its front edge protruding towards the first pressure plate 33 is connected to the rectangular inclined surface. In this embodiment, the rectangular silicone sheet 322 is 15 mm long and 5 mm wide, and is fixed to the inclined surface with instant adhesive. The front edge of the silicone sheet 322 is the long side of the rectangle, protruding forward and contacting the cotton cloth of the first pressure plate 33. The two pressure plates are arranged opposite each other and connected by bolts. Continuous fiber filaments pass through the gap between the two pressure plates. The gap is adjusted by the bolts so that the silicone sheet 322 abuts against the surface of the first pressure plate 33. When the filaments are pulled, they can pass through in the forward direction. After the filaments are cut, the roughness of the cotton cloth and the reverse resistance of the fiber sheet counteract the elasticity of the filaments and prevent the filaments from pulling back.

[0049] The filament path is as follows: the continuous fiber filament enters from the top of the continuous fiber extrusion device 5, exits through the outlet hole below the fixing frame 19 of the filament reverse check mechanism, and then enters the Teflon tube. It then passes through the throat tube 24 and the heating block 25 in sequence, and finally extends out from the nozzle 26. During this process, the cotton cloth layer on the surface of the first pressure plate 33 and the silicone sheet 322 arranged on the surface of the second pressure plate 32 directly contact and bite the filament. The contact pressure between the nozzle 26 and the workpiece surface and the resulting friction, combined with the movement of the nozzle, form a passive traction force on the continuous fiber filament, directly pulling the continuous fiber filament out. Under the pull, the filament enters the throat tube below, thus being smoothly and continuously conveyed out from the nozzle 26.

[0050] To accurately and intuitively observe the pressure value between the print head and the workpiece surface in the continuous fiber extrusion device, and to make appropriate adjustments during the printing process, this invention uses a tension / compression sensor 29 in the continuous fiber extrusion device. Figure 4 As shown, the tension / compression sensor 29 is connected to the display device 41 via a signal line, and further transmits the pressure signal to the motion controller 42 of the 3D printer. The compression spring 31 is connected to the tension / compression sensor 29, so the tension / compression sensor 29 can sense the pressure of the compression spring 29, thus transmitting the signal to the display device 41 first. The display device 41 is then connected to the motion controller 42 via a signal line. The motion controller 42 fine-tunes the position of the second slide 3 in real time according to the pressure signal to maintain stable nozzle pressure. When the pressure data captured by the tension / compression sensor 29 exceeds a preset threshold, the motion controller 42 triggers an emergency stop, stopping the equipment's movement to avoid collision and protect the equipment.

[0051] like Figure 5 As shown, the pneumatic scissors 7 consists of a cylinder and a scissor mechanism. The two air inlets of the pneumatic scissors 7 are connected to the air outlet A and air inlet B of the solenoid valve 43 respectively via air pipes. The air inlet of the solenoid valve 43 is connected to the air outlet of the pressure regulating valve 45, and the air inlet of the pressure regulating valve 45 is connected to the air compressor 46. A miniature solenoid valve controller 44 is installed at the original coil position of the solenoid valve 43. This controller is connected to the signal output port of the motion controller 42 and controls the cutting action of the scissors by controlling the opening and closing of the solenoid valve coil. The cutting action is encapsulated into M instructions through a custom macro program, realizing programmed control of the cutting action. The controller supports three working modes: single-action, inching, and automatic.

[0052] The ordinary resin extrusion device 36 adopts a remote filament feeding structure: the filament feeding mechanism 37 includes a driving wheel and a driven wheel, the driving wheel is driven by a stepper motor 34 on the back of the connecting plate; the pneumatic connector below the filament feeding mechanism 37 and the pneumatic connector 38 at the top of the radiator are connected by a Teflon tube, and the resin filament is transported to the nozzle through the filament feeding mechanism and the Teflon tube to complete the printing.

[0053] The standard printing operation steps for the above-mentioned composite additive manufacturing system are as follows:

[0054] Step 1: Before printing, adjust the gap between the two pressure plates of the filament reverse check mechanism according to the diameter of the pre-impregnated continuous fiber filament used, and fine-tune the pressure between the silicone sheet and the surface of the pure cotton cloth; measure and record the XYZ relative positions of the nozzles of the two extrusion devices.

[0055] Step 2: Plan the path and slice the workpiece according to its outline. When printing starts, input the global printing path GCode file containing all FDM parameters such as material, printing speed, and layer height, and print the workpiece in layers.

[0056] Step 3: Following the printing sequence, taking the ordinary resin printhead as an example, when the left resin printhead finishes printing and needs to be switched to the right continuous fiber printhead, the printer is first given the M0 instruction in the print path file. The device stops moving and the printing platform descends to the safe plane. Based on the relative Z-direction position of the two nozzles measured in Step 1, the first slide 12 on the left moves the ordinary resin extrusion device 36 upward, and the second slide 3 moves the continuous fiber extrusion device 5 downward in the opposite direction. The moving distance is the relative Z-direction height of the two nozzles, completing the printhead switching. At this time, the nozzle position of the resin extrusion device reaches the original printing plane.

[0057] Step 4: The printing platform is reset to the printing height, and the printing path GCode file is executed to continue printing the continuous fiber layer; when the continuous fiber layer printing is finished, the second slide 3 on the right side drives the continuous fiber extrusion device 5 to the cutting height, and the cutting is controlled by the pre-set M command. The M command controls the 100mm miniature 28 slide 6 to drive the pneumatic scissors 7 to move horizontally to the right to directly below the nozzle, and then controls the solenoid valve to turn on and off to drive the pneumatic scissors to cut the fiber; after the cutting is completed, the continuous fiber extrusion device 5 returns to the height position before the printing starts, and the pneumatic scissors and the 100mm miniature 28 slide 6 are reset.

[0058] Step 5: Repeat the above process until the entire workpiece is printed.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A resin and continuous fiber bonded composite additive manufacturing system, characterized by, include: The components include an inverted T-shaped hanger (2), a first slide (12), a second slide (3), a T-shaped connecting plate (11), a resin extrusion device (36), a continuous fiber extrusion device (5), and a fiber cutting mechanism. The inverted T-shaped bracket (2) has a first slide (12) installed vertically on the left side, a second slide (3) installed vertically on the right side, and a T-shaped connecting plate (11) fixedly installed in the lower middle part. The slider of the first slide (12) is fixed to the resin extrusion device (36) by the resin extrusion machine connector (35), and the slider of the second slide (3) is fixed to the continuous fiber extrusion device (5) by the continuous fiber extrusion machine connector (4); the first slide (12) and the second slide (3) can move synchronously in opposite directions to realize the rapid switching of the nozzles of the resin extrusion device (36) and the continuous fiber extrusion device (5); The fiber cutting mechanism is installed below the T-shaped connecting plate (11). After the fiber layer printing is completed, the pneumatic scissors (7) of the fiber cutting mechanism can move to the nozzle of the continuous fiber extrusion device (5) to complete the fiber cutting. The continuous fiber extrusion device (5) is equipped with a filament reverse check mechanism and outputs continuous fiber filaments in a passive traction manner.

2. The composite additive manufacturing system according to claim 1, characterized in that, The continuous fiber extrusion device (5) includes a filament reverse check mechanism located at the top and a fiber filament output mechanism located at the bottom. The reverse check mechanism for the filament includes a first pressure plate (33) and a second pressure plate (32) arranged in parallel. The inner surface of the first pressure plate (33) is covered with pure cotton cloth, and the inner surface of the second pressure plate (32) is arranged with several protruding structures from top to bottom. The front end of the protruding structure is an inclined surface facing the first pressure plate (33) at an angle downwards, and a silicone sheet with its leading edge protruding towards the first pressure plate (33) is connected to the inclined surface. The first pressure plate (33) and the second pressure plate (32) are arranged opposite to each other and connected by bolts. Continuous fiber filaments pass through the gap between the two pressure plates, and the gap can be adjusted by bolts until the silicone sheet abuts against the inner surface of the first pressure plate (33). The continuous fiber filament enters from the top of the filament reverse check mechanism, exits from the bottom of the filament reverse check mechanism, and is then fed out from the nozzle at the bottom of the fiber filament output mechanism.

3. The composite additive manufacturing system according to claim 2, characterized in that, The continuous fiber extrusion device (5) also includes a base and a vertical sliding assembly; the base consists of a lower fixed seat (13) and an upper fixed seat (14), the lower fixed seat (13) is fixedly connected to the continuous fiber extrusion machine connector (4); the vertical sliding assembly includes a vertical slide rail (34) fixed to the upper fixed seat (14), a slider (15) cooperating with the slide rail (34), and a rear connecting plate (17) fixed to the slider (15); the filament reverse check mechanism is installed on the top of the rear connecting plate (17) through a fixing frame (19); the top of the rear connecting plate (17) is also provided with a baffle (16) to prevent the slider (15) from overtravel; the bottom of the rear connecting plate (17) is fixedly connected to the front connecting plate (18), and the fiber filament output mechanism is installed on the front side of the front connecting plate (18).

4. The composite additive manufacturing system according to claim 3, characterized in that, The continuous fiber extrusion device (5) also includes an elastic pressure regulating structure; the elastic pressure regulating structure includes a vertical compression spring (31), a spring limiting block (30), a tension and pressure sensor (29), and a horizontal support plate (28); the horizontal support plate (28) is fixed to the bottom of the rear connecting plate (17), and the compression spring (31) is vertically arranged between the upper seat of the fixed seat (14) and the horizontal support plate (28); the upper seat of the fixed seat (14) is provided with a spring limiting block (30) at the top, and the tension and pressure sensor (29) is installed on the horizontal support plate (28), and the compression spring (31) is placed between the spring limiting block (30) and the tension and pressure sensor (29).

5. The composite additive manufacturing system according to claim 4, characterized in that, The fiber output mechanism includes a heat dissipation and heating assembly connected to the front connecting plate (18) via a radiator fixing block (21); the heat dissipation and heating assembly includes a radiator (23), a fan (22), a pneumatic connector (20), a throat (24), a heating block (25), a heating rod, a thermocouple, and a nozzle (26); the fan (22) is mounted on the radiator (23), and the top end is connected to the pneumatic connector (20), with a Teflon tube inserted inside the pneumatic connector (20); one end of the throat (24) is threaded to the radiator (23), and the other end is connected to the heating block (25); the heating block (25) is fixed to the bottom of the front connecting plate (18) via a pad (27), a heating rod is installed inside the heating block (25), a thermocouple is installed at the front end, and a nozzle (26) is connected to the bottom; the inlet and outlet of the nozzle (26) are rounded.

6. The composite additive manufacturing system according to claim 1, characterized in that, The wire cutting mechanism includes a first micro linear slide (8), a second micro linear slide (6), a slide transition plate (10), a scissor connecting block (9), and a pneumatic scissor (7). The first micro linear slide (8) is longitudinally mounted on the lower surface of the T-shaped connecting plate (11), and its slider is laterally mounted on the second micro linear slide (6) through the slide transition plate (10). The slider of the second micro linear slide (6) is fixed to the pneumatic scissor (7) through the scissor connecting block (9).

7. The composite additive manufacturing system according to claim 4, characterized in that, The tension / compression sensor (29) is connected to the display device (41) via a signal line and transmits the pressure signal to the motion controller (42) of the 3D printer. The motion controller (42) finely adjusts the position of the second slide (3) in real time according to the pressure signal. When the pressure data is greater than the preset threshold, the motion controller (42) triggers the device to stop suddenly.

8. The composite additive manufacturing system according to claim 1, characterized in that, The pneumatic scissors (7) are equipped with a solenoid valve (43), a micro solenoid valve controller (44), a pneumatic pressure regulating valve (45), and an air compressor (46). The two air inlets of the pneumatic scissors (7) are connected to the air outlets A and B of the solenoid valve (43) through air pipes; the air inlet of the solenoid valve (43) is connected to the air outlet of the pressure regulating valve (45), and the air inlet of the pressure regulating valve (45) is connected to the air compressor (46). A miniature solenoid valve controller (44) is installed at the original coil of the solenoid valve (43). The controller is connected to the signal output port of the motion controller (42). The wire cutting action is encapsulated into M instructions through a custom macro program. The controller supports three working modes: single action, inching, and automatic.

9. The composite additive manufacturing system according to claim 1, characterized in that, The resin extrusion device (36) adopts a remote wire feeding structure, including a wire feeding mechanism (37), a stepper motor (34) and a Teflon tube; The wire feeding mechanism (37) includes a drive wheel and a driven wheel. The drive wheel is driven by a stepper motor (34) on the back of the connecting plate. The pneumatic connector below the wire feeding mechanism (37) and the pneumatic connector (38) at the top of the radiator are connected by a Teflon tube.

10. A composite additive manufacturing method combining resin and continuous fibers, based on the composite additive manufacturing system according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Before printing, adjust the gap between the two pressure plates of the filament reverse check mechanism according to the diameter of the pre-impregnated continuous fiber filament, calibrate the clamping force between the fiber sheet and the pure cotton cloth, and measure and record the XYZ relative positions of the nozzles of the two extrusion devices. Step 2: Plan and slice the workpiece, import the global print path GCode file containing print parameters, and start layered printing; Step 3: After the resin layer is printed, the printer executes the M0 command to pause and the printing platform descends to the safe plane; the first slide (12) drives the resin extrusion device (36) to move upward, and the second slide (3) drives the continuous fiber extrusion device (5) to move downward in the opposite direction in sync. The moving distance is the relative height of the two nozzles in the Z direction, and the nozzle switching is completed. Step 4: The printing platform is reset to the printing height and the continuous fiber layer is printed. After the fiber layer printing is completed, the continuous fiber extrusion device (5) is raised to the cutting height. The M command controls the second micro linear slide (6) to drive the pneumatic scissors (7) to move directly below the nozzle to complete the cutting. All components are reset. Step 5: Repeat steps 3 to 4 until the workpiece is printed.

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