A continuous fiber composite material 3D printing tension control device and method

Abstract

The present invention relates to a tension control device and method for 3D printing of continuous fiber composite materials, the device comprising: a tension monitoring module, a real-time adjustment module for prepreg tension, a bracket module for installing the tension monitoring module and the real-time adjustment module; the real-time adjustment module is fixedly connected to the bracket module, and the tension monitoring module is installed above the real-time adjustment module; the prepreg as the composite material to be printed passes through the first fiber duct joint, the tension monitoring module, the variable diameter channel and the fiber duct joint of the bracket module in sequence through the fiber duct, and is finally deposited on the printing platform through the print head. Compared with the prior art, the present invention integrates tension monitoring and real-time adjustment, can measure and adjust fiber micro-tension and negative tension, has the advantages of compact structural design, simple operation and control, does not affect the automatic fiber feeding, high sensitivity, etc., effectively ensures the quality of 3D printing and improves the stability of 3D printing.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material 3D printing, and in particular to a tension control device and method for 3D printing of continuous fiber composite materials. Background Art

[0002] Composite materials have excellent properties such as light weight, high strength, high temperature corrosion resistance, and good fatigue resistance. They are widely used in various high-precision equipment and high-tech industries, such as the aerospace industry, vehicle engineering industry, rail transit industry, and ship engineering industry.

[0003] In recent years, the continuous fiber composite 3D printing process has been gradually applied to the manufacture of composite lightweight structures due to its high degree of automation, strong designability, easy overall molding, no need for complex molds, and short manufacturing cycle. Unlike the molten deposition 3D printing process of thermoplastic pure resin or short fiber reinforced materials, in the process of continuous fiber composite 3D printing, since the continuous fiber cannot be stretched or compressed, the fiber material feed speed must match the printing speed. If the feed speed is greater than the printing speed, the slight difference will cause the laying fiber tortuosity, thereby affecting the mechanical properties and dimensional accuracy of the printed parts. In severe cases, the fiber filaments will soften and accumulate in the nozzle, causing the nozzle to clog. If the feed speed is less than the printing speed, the fiber tension is too large, which will cause the pre-fiber to break and affect the printing success rate. In addition, during the printing process, there is also a fiber drag phenomenon, especially when printing a small curvature path, which will cause the actual fiber deposition to be less than the feed amount, further exacerbating the mismatch between the feed speed and the printing speed. Therefore, achieving accurate matching between the feed speed of continuous fiber materials and the 3D printing speed is a key technical challenge to ensure high-quality and efficient 3D printing of continuous fiber composites.

[0004] Although the existing technology partially realizes the tension control function, it still has problems such as poor control accuracy and delayed response, especially the inability to effectively monitor the negative tension state to avoid the risk of fiber clogging. Summary of the invention

[0005] The purpose of the present invention is to provide a continuous fiber composite material 3D printing tension control device and method to overcome the defects of poor control accuracy and response lag in the above-mentioned prior art, which is used to solve the problems such as the mismatch between the feed speed of composite material prepreg and the printing speed during 3D printing. The tension sensor involved in the invention monitors the fiber tension in real time during 3D printing, and feeds back real-time pressure signals to the printer control system, thereby driving the screw slider module to quickly adjust the fiber tension and compensate for the mismatch between the feed speed and the printing speed, effectively ensuring the quality of composite material 3D printing while improving the stability of the process.

[0006] The present invention provides a continuous fiber composite material 3D printing tension control device, comprising: a tension monitoring module, a real-time adjustment module for controlling the tension of prepreg, and a support module for installing the tension monitoring module and the real-time adjustment module;

[0007] The tension monitoring module is installed above the real-time adjustment module; the prepreg of the composite material to be printed passes through the first fiber duct joint of the support module, the tension monitoring module, the variable diameter channel and the fiber duct joint in sequence through the fiber duct, and is finally deposited on the printing platform through the print head.

[0008] The tension monitoring module comprises: a fiber guide tube, a mechanical sensor, a spring connector, a spring, an L bracket, a second fiber guide tube connector, a slider and a slide rail;

[0009] The mechanical sensor is connected to the sensor connector of the real-time adjustment module, and the other side is connected to the spring connector; one end of the spring is fixed in the connecting groove of the spring connector, and the other end is fixed in the connecting groove of the L bracket; the L bracket is connected to the slider, the slider is installed on the slide rail, and the slide rail is fixed on the bottom plate of the support frame; the second fiber duct connector is connected to the L bracket; one end of the fiber duct is fixed to the first fiber duct connector of the bracket module, and then the other end of the fiber duct is fixed to the second fiber duct connector through the spring connector, the spring, and the L bracket in sequence, and the end of the fiber duct is inserted into the variable diameter through hole of the variable diameter channel of the bracket module, and the gap is matched with the variable diameter channel.

[0010] Furthermore, the real-time adjustment module is fixedly connected to the bracket module by bolts, and the tension monitoring module is installed above the real-time adjustment module by bolts.

[0011] Furthermore, the real-time adjustment module includes a screw sliding module and a sensor joint; the sensor joint is fixed above a slider of the screw sliding module, and the screw sliding module is fixed on a bottom plate of a support frame of the bracket module.

[0012] Furthermore, the support module includes: a first fiber duct joint, a support frame, a variable diameter channel and a fiber duct joint; the first fiber duct joint is fixed on one side of the support frame, the variable diameter channel is fixed on the other side of the support frame, the slide rail is installed on the bottom plate of the support frame, and the fiber duct joint is installed at the other end of the variable diameter channel.

[0013] Furthermore, the spring connector, spring, L bracket, second fiber duct joint, the variable diameter channel of the bracket module, and the fiber duct joint serve as a wire feeding channel, and the inner hole axis remains coaxial, and the axial direction is parallel to the moving direction of the slide rail of the tension monitoring module.

[0014] Furthermore, the length of the fiber conduit is greater than the shortest distance between the second fiber conduit connector and the first fiber conduit connector of the support module, presenting an arc shape with a certain curvature. During the 3D printing process, if the feed speed is less than the printing speed, the prepreg filaments squeeze the arc segment fiber conduit inwards, and the fiber conduit moves in the straightening direction, driving the spring to extend together through the second fiber conduit connector; if the feed speed is greater than the printing speed, the prepreg filaments squeeze the arc segment fiber tube outwards, and the fiber conduit moves in the bending direction, driving the spring to shorten together through the second fiber conduit connector.

[0015] Furthermore, the fiber duct is connected to the first fiber duct joint and the second fiber duct joint of the support module, ensuring that the fiber duct length between the two fiber duct joints is a constant value.

[0016] Furthermore, the end of the fiber conduit extends out of the second fiber conduit connector by a certain length and is inserted into the variable diameter channel of the bracket module to achieve low-friction free sliding, and the insertion length is greater than the maximum movable distance of the slider.

[0017] The present invention also provides a method for controlling the tension of continuous fiber composite material 3D printing, comprising the following steps:

[0018] S1: Set the target tension control value x N, monitor the tension value y N in real time by collecting the pressure signal and compare it with the target tension control value x N; if the current feed speed is less than the feed speed corresponding to the target tension control value x, the prepreg filament squeezes the arc-shaped fiber duct inward, and the fiber duct moves in the straightening direction, and drives the spring to stretch together through the second fiber duct joint, and the tension value y measured by the mechanical sensor will be less than the target tension control value x. At this time, if the device supports real-time flow adjustment, the flow of the remote extruder is adjusted to increase by a%, otherwise, the slider position of the screw sliding module needs to be adjusted to increase by bmm, so that the tension value returns to the target control value; if the current feed speed is greater than the feed speed corresponding to the target tension control value x, the prepreg filament squeezes the arc-shaped fiber duct outward, and the fiber duct moves in the bending direction, and drives the spring to shorten together through the second fiber duct joint, and the tension value y measured by the mechanical sensor will be greater than the target tension control value x. At this time, if the device supports real-time flow adjustment, the flow of the remote extruder is adjusted to decrease by a%, otherwise, the slider position of the screw sliding module needs to be adjusted to decrease by b mm, so that the tension value returns to the target control value;

[0019] S2: Simultaneously monitor the movement amount Δs of the slider of the lead screw sliding module and feedback relevant commands to the host computer; when 0 mm < |Δs| < c mm, where b < c < d and d < the maximum stroke of the lead screw sliding module, there is no need to feedback commands to the host computer, and S2 is repeatedly executed; when c mm < |Δs| < d mm, feedback the flow control command G1 E(Δs) to the host computer to adjust the feed rate of the remote extruder, and then continue to execute S2; when |Δs| > d mm, feedback a pause command to the host computer to abort the printing.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] The present invention integrates tension monitoring and real-time adjustment, can measure micro-tension and negative tension, and has the advantages of compact structure design, simple operation and control, and does not affect the automatic feeding of fibers, high sensitivity, etc., effectively ensuring the quality of 3D printing molding while improving the stability of 3D printing. The tension sensor of the present invention monitors the fiber tension magnitude in the 3D printing process in real time, feeds back real-time pressure signals to the printer control system, thereby driving the lead screw sliding module to adjust the fiber tension, compensating for the mismatch between the feeding speed and the printing speed, effectively reducing the corrugation of the deposited fibers, improving the tensile and bending properties and dimensional accuracy of the 3D printed composite material, and effectively ensuring the high-stability and high-quality 3D printing of continuous carbon fiber reinforced composite materials. Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the overall structure of the 3D printing tension control device for continuous fiber composite materials;

[0023] Figure 2 It is a schematic diagram of the structure of the tension monitoring module;

[0024] Figure 3 It is a schematic diagram of the structure of the fiber conduit and the prepreg (when the feeding speed is less than the printing speed);

[0025] Figure 4 It is a schematic diagram of the structure of the fiber conduit and the prepreg (when the feeding speed is greater than the printing speed);

[0026] Figure 5 It is a partial enlarged sectional view of the 3D printing tension control device for continuous fiber composite materials;

[0027] Figure 6 It is a schematic sectional view of the structure of the 3D printing tension control device for continuous fiber composite materials;

[0028] Figure 7 It is a flowchart of the 3D printing tension control method for continuous fiber composite materials.

[0029] Reference numerals: 1-tension monitoring module, 11-prepreg, 12-fiber guide tube, 13-mechanical sensor, 14-spring connector, 15-spring, 16-L bracket, 17-second fiber guide tube connector, 18-slider, 19-slide rail;

[0030] 2-real-time adjustment module, 21-screw sliding module, 22-sensor connector;

[0031] 3-support module, 31-first fiber duct connector, 32-support frame, 33-variable channel, 34-fiber duct connector. DETAILED DESCRIPTION

[0032] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0033] Example 1

[0034] This embodiment provides a continuous fiber composite material 3D printing tension control device, such as Figure 1 , 2 , 5, 6, comprising: a tension monitoring module 1, a real-time adjustment module 2 for adjusting the tension of the prepreg filament 11 during 3D printing, and a support module 3 for installing the tension monitoring module 1 and the real-time adjustment module 2;

[0035] The real-time adjustment module 2 is fixedly connected to the support module 3, and the tension monitoring module 1 is installed above the real-time adjustment module 2; the prepreg filament 11 of the composite material to be printed passes through the first fiber duct joint 31 of the support module 3, the tension monitoring module 1, the variable diameter channel 33 and the fiber duct joint 34 in sequence through the fiber duct 12, and is finally deposited on the printing platform through the print head.

[0036] like Figure 2 As shown, the tension monitoring module 1 includes: a fiber guide tube 12, a mechanical sensor 13, a spring connector 14, a spring 15, an L bracket 16, a second fiber guide tube connector 17, a slider 18 and a slide rail 19;

[0037] The mechanical sensor 13 is bolted to the sensor connector 22 of the real-time adjustment module 2, and the other side is bolted to the spring connector 14; one end of the spring 15 is fixed in the connecting groove of the spring connector 14, and the other end is fixed in the connecting groove of the L bracket 16; the L bracket 16 is bolted to the slider 18, the slider 18 is installed on the slide rail 19, and the slide rail 19 is fixed on the bottom plate of the support frame 32; the second fiber duct connector 17 is threadedly connected to the L bracket 16; one end of the fiber duct 12 is fixed to the first fiber duct connector 31 of the bracket module 3, and then the other end of the fiber duct 12 is fixed to the second fiber duct connector 17 through the spring connector 14, the spring 15, and the L bracket 16 in sequence, and the end of the fiber duct 12 is inserted into the reducing through hole of the reducing channel 33 of the bracket module 3, and is gap-matched with the reducing channel 33.

[0038] In a specific implementation, the real-time adjustment module 2 is fixedly connected to the support module 3 by bolts, and the tension monitoring module 1 is installed above the real-time adjustment module 2 by bolts.

[0039] In a specific implementation, the real-time adjustment module 2 includes a screw sliding module 21 and a sensor joint 22 ; the sensor joint 22 is fixed above the slider of the screw sliding module 21 , and the screw sliding module 21 is fixed on the bottom plate of the support frame 32 of the bracket module 3 .

[0040] like Figure 6 As shown, in a specific embodiment, the support module 3 includes: a first fiber duct joint 31, a support frame 32, a reducing channel 33 and a fiber duct joint 34; the first fiber duct joint 31 is fixed on one side of the support frame 32, the reducing channel 33 is fixed on the other side of the support frame 32, the slide rail 19 is installed on the bottom plate of the support frame 32 by bolt connection, and the fiber duct joint 34 is installed on the other end of the reducing channel 33.

[0041] In a specific embodiment, the spring connector 14, spring 15, L bracket 16, second fiber duct joint 17 and the variable diameter channel 33 and fiber duct joint 34 of the bracket module 3 serve as wire feeding channels, and the inner hole axis remains coaxial, and the axial direction is parallel to the moving direction of the slide rail 19 of the tension monitoring module 1.

[0042] In a specific embodiment, the length of the fiber conduit 12 is greater than the shortest distance between the second fiber conduit connector 17 and the first fiber conduit connector 31 of the support module 3, and presents an arc shape with a certain curvature. Figure 3 As shown, if the feeding speed is less than the printing speed, the prepreg filament 11 presses the arc-shaped fiber guide tube inward, and the fiber guide tube 12 moves in the straightening direction, driving the spring 15 to extend together through the second fiber guide tube joint 17, as shown in FIG. Figure 4 As shown, if the feeding speed is greater than the printing speed, the prepreg 11 squeezes the arc-shaped fiber tube outward, and the fiber guide tube 12 moves in the bending direction, driving the spring 15 to shorten together through the second fiber guide tube joint 17.

[0043] In a specific embodiment, the fiber duct 12 is tightly connected to the first fiber duct connector 31 and the second fiber duct connector 17 of the bracket module 3, ensuring that the fiber duct length between the two fiber duct connectors is a constant value. Thus, the reciprocating motion of the fiber duct 12 can correctly reflect the magnitude of the fiber tension. When the fiber duct 12 moves in the prepreg feeding direction or the opposite direction, it drives the reciprocating motion of the L bracket 16, thereby driving the extension or shortening motion of the spring 15. The reciprocating motion of the L bracket 16 is achieved by the movement of the slider 18 on the slide rail 19. The end of the fiber duct 12 also makes a reciprocating motion of a certain distance in the variable diameter through hole of the variable diameter channel 33, such as Figure 5 shown.

[0044] In a specific embodiment, the end of the fiber duct 12 extends a certain length from the second fiber duct connector 17 and is inserted into the variable diameter channel 33 of the bracket module 3 to achieve low-friction free sliding, and the insertion length is greater than the maximum movable distance of the slider 18.

[0045] This embodiment also provides a method for controlling the tension of continuous fiber composite material 3D printing. Figure 7 As shown, the following steps are included:

[0046] S1: Set the target tension control value x N, monitor the tension value y N in real time by collecting the pressure signal and compare it with the target tension control value x N; if the current feed speed is less than the feed speed corresponding to the target tension control value x, the prepreg 11 squeezes the arc-shaped fiber duct inward, and the fiber duct 12 moves in the straightening direction, and the spring 15 is driven to extend together through the second fiber duct connector 17. The tension value y measured by the mechanical sensor 13 will be less than the target tension control value x. At this time, if the device supports real-time flow adjustment, the flow of the remote extruder is adjusted to increase by a%, otherwise the slider position of the screw sliding module 21 needs to be adjusted to increase by b. mm, so that the tension value returns to the target control value; if the current feed speed is greater than the feed speed corresponding to the target tension control value x, the prepreg 11 squeezes the arc-shaped fiber guide tube outward, and the fiber guide tube 12 moves in the bending direction, and the spring 15 is driven to shorten together through the second fiber guide tube joint 17. The tension value y measured by the mechanical sensor 13 will be greater than the target tension control value x. At this time, if the device supports real-time flow adjustment, the flow of the remote extruder is adjusted to decrease by a%, otherwise, the slider position of the screw sliding module 21 needs to be adjusted to decrease by b mm, so that the tension value returns to the target control value;

[0047] S2: Simultaneously monitor the movement amount Δs of the slider of the lead screw sliding module 21 and feedback relevant commands to the host computer; when 0 mm < |Δs| < c mm, where b < c < d and d < the maximum stroke of the lead screw sliding module, there is no need to feedback commands to the host computer, and S2 is repeatedly executed; when c mm < |Δs| < d mm, feedback the flow control command G1 E(Δs) to the host computer to adjust the feed rate of the remote extruder, and then continue to execute S2; when |Δs| > d mm, feedback a pause command to the host computer to abort the printing.

[0048] Components not elaborated in detail in this embodiment are all existing components that can be purchased through public channels.

[0049] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A continuous fiber composite material 3D printing tension control device, characterized in that: include: A tension monitoring module (1), a real-time adjustment module (2) for controlling the tension of the prepreg (11), and a support module (3) for installing the tension monitoring module (1) and the real-time adjustment module (2); The tension monitoring module (1) is installed above the real-time adjustment module (2); the prepreg (11) of the composite material to be printed passes through the first fiber duct joint (31) of the support module (3), the tension monitoring module (1), the variable diameter channel (33) and the fiber duct joint (34) in sequence through the fiber duct (12), and is finally deposited on the printing platform through the print head; The tension monitoring module (1) comprises: a fiber duct (12), a mechanical sensor (13), a spring connector (14), a spring (15), an L bracket (16), a second fiber duct connector (17), a slider (18) and a slide rail (19); the fiber duct (12) is longer than the shortest distance between the second fiber duct connector (17) and the first fiber duct connector (31) of the bracket module (3), and presents an arc shape with a certain curvature; The mechanical sensor (13) is connected to the sensor connector (22) of the real-time adjustment module (2), and the other side is connected to the spring connector (14); one end of the spring (15) is fixed in the connection groove of the spring connector (14), and the other end is fixed in the connection groove of the L bracket (16); the L bracket (16) is connected to the slider (18), the slider (18) is installed on the slide rail (19), and the slide rail (19) is fixed on the bottom plate of the support frame (32); the second fiber duct connector (17) is connected to the L bracket (16); one end of the fiber duct (12) is fixed to the first fiber duct connector (31) of the bracket module (3), and then the other end of the fiber duct (12) is fixed to the second fiber duct connector (17) through the spring connector (14), the spring (15), and the L bracket (16) in sequence, and the end of the fiber duct (12) is inserted into the variable diameter through hole of the variable diameter channel (33) of the bracket module (3) and is clearance-matched with the variable diameter channel (33); The real-time adjustment module (2) comprises a screw sliding module (21) and a sensor joint (22); the sensor joint (22) is fixed above a slider of the screw sliding module (21), and the screw sliding module (21) is fixed on a bottom plate of a support frame (32) of the bracket module (3).

2. A continuous fiber composite material 3D printing tension control device according to claim 1, characterized in that: The real-time adjustment module (2) and the support module (3) are fixedly connected via bolts, and the tension monitoring module (1) is installed above the real-time adjustment module (2) via bolts.

3. A continuous fiber composite material 3D printing tension control device according to claim 1, characterized in that: The support module (3) comprises: a first fiber duct joint (31), a support frame (32), a diameter-changing channel (33) and a fiber duct joint (34); the first fiber duct joint (31) is fixed to one side of the support frame (32), the diameter-changing channel (33) is fixed to the other side of the support frame (32), the slide rail (19) is mounted on the bottom plate of the support frame (32), and the fiber duct joint (34) is mounted on the other end of the diameter-changing channel (33).

4. A continuous fiber composite material 3D printing tension control device according to claim 1, characterized in that: The spring connector (14), spring (15), L bracket (16), second fiber conduit connector (17), and the variable-diameter channel (33) and fiber conduit connector (34) of the bracket module (3) serve as the wire threading channels, with their inner hole axes coaxial and the axis direction parallel to the moving direction of the slide rail (19) of the tension monitoring module (1).

5. The continuous fiber composite material 3D printing tension control device according to claim 1, characterized in that: The fiber conduit (12) is connected to the first fiber conduit connector (31) and the second fiber conduit connector (17) of the bracket module (3) to ensure that the length of the fiber conduit between the two fiber conduit connectors is a fixed value.

6. A continuous fiber composite material 3D printing tension control device according to claim 1, characterized in that: The end of the fiber conduit (12) extends a certain length beyond the second fiber conduit connector (17) and is inserted into the variable-diameter channel (33) of the bracket module (3) to achieve low-friction free sliding, and the insertion length is greater than the maximum movable distance of the slider (18).

7. A method for controlling the tension of continuous fiber composite material 3D printing using the device according to any one of claims 1 to 6, characterized in that: It includes the following steps: S1: Set the target tension control value to x N. Monitor the tension value y N in real time by collecting pressure signals and compare it with the target tension control value x N. If the current feeding speed is less than the feeding speed corresponding to the target tension control value x, the prepreg wire (11) squeezes the arc-shaped fiber conduit inward, and the fiber conduit (12) moves in the straightening direction. The spring (15) is driven by the second fiber conduit connector (17) to perform an elongation movement together. The tension value y measured by the mechanical sensor (13) will be less than the target tension control value x. At this time, if the device supports real-time flow adjustment, adjust the flow of the distal extruder to increase by a %, otherwise, adjust the slider position of the lead screw sliding module (21) to increase by b mm to make the tension value return to the target control value. If the current feeding speed is greater than the feeding speed corresponding to the target tension control value x, the prepreg wire (11) squeezes the arc-shaped fiber conduit outward, and the fiber conduit (12) moves in the bending direction. The spring (15) is driven by the second fiber conduit connector (17) to perform a shortening movement together. The tension value y measured by the mechanical sensor (13) will be greater than the target tension control value x. At this time, if the device supports real-time flow adjustment, adjust the flow of the distal extruder to decrease by a %, otherwise, adjust the slider position of the lead screw sliding module (21) to decrease by b mm to make the tension value return to the target control value. S2: Simultaneously monitor the movement amount Δs of the slider of the lead screw sliding module (21) and feedback relevant commands to the host computer. When 0 mm < |Δs| < c mm, where b < c < d and d < the maximum stroke of the lead screw sliding module, no command needs to be feedback to the host computer, and S2 is repeated. When c mm < |Δs| < d mm, feedback the flow control command G1 E(Δs) to the host computer to adjust the feeding amount of the distal extruder, and then continue to execute S2. When |Δs| > d mm, feedback a pause command to the host computer to abort the printing.

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