Robotic additive manufacturing apparatus and method for continuous production of ultrasonic assisted hybrid fiber ceramic composites

Abstract

The application provides a robot additive manufacturing device and method for ultrasonic-assisted continuous preparation of composite fiber ceramic composites, and belongs to the field of composite fibers.The device comprises a first feeding mechanism for outputting a fiber bundle; a heating cavity filled with molten resin material; a first ultrasonic mechanism and a second ultrasonic mechanism oppositely arranged on two inner walls of the heating cavity; the first ultrasonic mechanism and the second ultrasonic mechanism are symmetrically arranged on both sides of the fiber bundle transmission direction, and the ultrasonic wave emission direction of the first ultrasonic mechanism and the second ultrasonic mechanism is the vertical direction of the fiber bundle transmission direction; when the fiber bundle passes through the heating cavity, the fiber bundle is subjected to ultrasonic waves and the internal fiber filaments are scattered and uniformly distributed, so that the resin material wraps each fiber filament, and after high-temperature ceramic treatment, a high-performance fiber-reinforced ceramic composite is prepared.The application solves the problems of poor resin flowability and high fiber aggregation in the prior art, so that the resin is difficult to uniformly wrap the fiber, and obvious pores and uneven fiber distribution occur in the subsequent ceramic treatment process.

Description

Technical Field

[0001] This invention relates to the field of composite fiber technology, and in particular to a robotic additive manufacturing apparatus and method for the continuous preparation of ultrasonic-assisted composite fiber ceramic composites. Background Technology

[0002] Continuous fiber reinforced silicon carbide (SiC) ceramic matrix composites have advantages such as being lightweight, high-strength, high-temperature resistant, and corrosion resistant. Moreover, by introducing a continuous fiber phase, they overcome the problem of high brittleness in single ceramic materials. They are an advanced structural material that has attracted widespread attention and are the preferred material in aerospace, nuclear energy engineering, automotive transportation and other fields.

[0003] Chinese patent CN110229012A discloses a molding method for a continuous fiber combined with short carbon fiber toughened ceramic matrix composite material. The method involves mixing a ceramic precursor, an organic solvent, and short carbon fibers as a direct writing slurry. This slurry is loaded into the outer cylinder of a coaxial nozzle, while the continuous fibers are loaded into the inner cylinder. This results in a preform with a "core-shell" structure: a central continuous fiber core and a short carbon fiber toughened ceramic matrix as the outer shell. The ceramic matrix is ​​derived from the pyrolysis of the ceramic precursor. The short carbon fibers are oriented within the matrix, and the outer layer of short carbon fibers is also oriented, thus significantly improving the toughness of the ceramic material.

[0004] However, the current problem with composite fibers is that the main fibers are highly agglomerated and show no signs of dispersion, and the molten resin has poor fluidity, making it difficult for the composite material to uniformly wrap the fibers. This results in obvious pores during the densification process of the composite fiber material, and the fibers are easily damaged, which seriously limits the improvement of the mechanical properties of the products. Summary of the Invention

[0005] In view of this, the present invention proposes a robotic additive manufacturing device and method for continuous preparation of ultrasonic-assisted composite fiber ceramic composites, which is used to solve the problem that the main fiber is highly agglomerated and shows no signs of dispersion, and the molten resin has poor fluidity, making it difficult for the composite material to uniformly wrap the fiber, resulting in obvious pores and easy damage to the fiber during the densification process of the composite fiber material.

[0006] The technical solution of this invention is implemented as follows: This invention provides a robotic additive manufacturing device for the continuous preparation of ultrasonic-assisted composite fiber ceramic composites, comprising a first feeding mechanism that outputs fiber bundles; a heating chamber disposed after the first feeding mechanism and filled with molten resin material; a first ultrasonic mechanism and a second ultrasonic mechanism disposed opposite to each other on two inner walls of the heating chamber; and an extrusion head disposed after the heating chamber and extruding the fiber bundles for additive manufacturing; wherein, the first ultrasonic mechanism and the second ultrasonic mechanism are symmetrically disposed on both sides of the fiber bundle transmission direction, and the ultrasonic emission direction of the first ultrasonic mechanism and the second ultrasonic mechanism is perpendicular to the fiber bundle transmission direction; when the fiber bundle passes through the heating chamber, it is subjected to ultrasonic waves, which disperse the internal fiber filaments and cause the resin material to uniformly coat each fiber filament.

[0007] Based on the above technical solutions, preferably, a third ultrasonic mechanism is also included, which is disposed on the inner wall of the heating chamber near the extrusion head. The third ultrasonic mechanism emits ultrasonic waves in the opposite direction of fiber bundle transmission.

[0008] More preferably, it also includes a second feeding mechanism that feeds resin filament into the heating chamber; a robotic arm on which the first feeding mechanism, the heating chamber, the extruder head, and the second feeding mechanism are mounted; and a printing plane; wherein the robotic arm drives the first feeding mechanism, the heating chamber, the extruder head, and the second feeding mechanism to move synchronously in multiple axes relative to the printing plane.

[0009] More preferably, when the robotic arm drives the extrusion head to extrude fiber bundles on the printing plane, the tilt angle of the fiber bundles relative to the printing plane changes; the first ultrasonic mechanism and the second ultrasonic mechanism are respectively located on the front and rear sides of the extrusion head's moving direction, and the power of the first ultrasonic mechanism and the second ultrasonic mechanism also changes accordingly.

[0010] More preferably, the relationships between the power of the first ultrasonic mechanism and the inclination angle of the fiber bundle are as follows:

[0011]

[0012] Where P0 is the initial power of the first or second ultrasonic mechanism, and ΔP max θ represents the maximum power change of either the first or second ultrasonic mechanism, and θ is the tilt angle of the fiber bundle.

[0013] More preferably, the power of the third ultrasonic device is P0.

[0014] Even more preferably, the extrusion speed of the extruder head is directly proportional to the power of the third ultrasonic mechanism.

[0015] More preferably, the fiber bundle is made of continuous carbon fiber or continuous silicon carbide fiber material, and the resin wire is made of thermoplastic resin.

[0016] On the other hand, the present invention also provides a robotic additive manufacturing method for the continuous preparation of ultrasonic-assisted composite fiber ceramic composites. Using the aforementioned robotic additive manufacturing apparatus for the continuous preparation of ultrasonic-assisted composite fiber ceramic composites, the method includes the following steps: Step 1, starting the first feeding mechanism to output fiber bundles and starting the second feeding mechanism to feed resin filaments into the heating chamber, where the heating chamber melts the resin filaments to obtain molten resin material; Step 2, simultaneously starting the first, second, and third ultrasonic mechanisms to emit ultrasonic waves, the fiber bundle passes through the heating chamber and is subjected to ultrasonic waves, the fiber bundle is broken up and its internal fibers are separated, allowing the resin material to uniformly coat each fiber filament; Step 3, the extruder extrudes the fiber bundle, and the robotic arm drives the extruder to use the extruded fiber bundle for additive manufacturing and printing to obtain a preform, the extrusion speed of the extruder being matched in real time with the power of the third ultrasonic mechanism.

[0017] Based on the above technical solutions, preferably, step four is also included: placing the blank in a thermosetting phenolic resin solution and impregnating it under vacuum, then drying it and allowing the phenolic resin to solidify and coat the blank.

[0018] The robotic additive manufacturing apparatus and method for continuous preparation of ultrasonic-assisted composite fiber ceramic composites of the present invention have the following advantages over the prior art:

[0019] (1) This invention utilizes synchronous ultrasonic-assisted robotic arm molding technology to address the problems in existing technologies, such as poor resin flowability and high fiber agglomeration, which make it difficult for the resin to uniformly coat the fibers, leading to significant porosity and fiber damage during subsequent ceramicization processes. Only a robotic arm can meet the complex process requirements and achieve high-quality material preparation. The robotic arm's automated operation and real-time feedback adjustment capabilities reduce human intervention and improve production efficiency. The robotic arm can operate precisely according to preset process parameters and motion trajectories, ensuring consistent product quality. In contrast, traditional manufacturing methods are easily affected by human factors, resulting in significant fluctuations in product quality.

[0020] (2) The present invention adjusts the power of the two ultrasonic mechanisms on the left and right sides of the fiber bundle in real time according to the change of the tilt angle of the fiber bundle relative to the printing plane during the printing process, so as to avoid uneven distribution of resin inside the fiber bundle and achieve uniform coating of resin and fiber filament.

[0021] (3) The present invention adjusts the initial power of each ultrasonic mechanism according to the extrusion speed of the extruder, thereby adjusting the thickness of the interface layer according to actual needs, thus ensuring that the toughness and strength of the composite fiber meet the requirements. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the additive manufacturing apparatus of the present invention;

[0024] Figure 2 This is an enlarged view of the fiber filaments of the composite fiber of the present invention;

[0025] Figure 3 This is a schematic diagram of another embodiment of the additive manufacturing apparatus of the present invention;

[0026] Figure 4 This is a schematic diagram showing the microscopic comparison of composite fibers in Test Examples 2 and 4 of the present invention, where a is Test Example 4 and b is Test Example 2.

[0027] In the figure: 1. First feeding mechanism; 11. Fiber bundle; 111. Fiber filament; 2. Heating chamber; 21. Resin material; 3. First ultrasonic mechanism; 4. Second ultrasonic mechanism; 5. Extruder head; 6. Third ultrasonic mechanism; 7. Second feeding mechanism; 71. Resin filament; 8. Robotic arm; 9. Printing plane. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, combined with Figure 2 The present invention discloses a robotic additive manufacturing apparatus for continuous preparation of ultrasonic-assisted composite fiber ceramic composite materials, comprising a first feeding mechanism 1, a heating chamber 2, a first ultrasonic mechanism 3, a second ultrasonic mechanism 4, and an extruder 5.

[0030] The first feeding mechanism 1 outputs a fiber bundle 11. The fiber bundle 11 is formed by a tight bundle of several fiber filaments 111.

[0031] The heating chamber 2 is a hollow shell, and its outer shell can be made of high-temperature and corrosion-resistant stainless steel. The heating chamber 2 is located after the first feeding mechanism 1 and is filled with molten resin material 21. Heating wire mesh or heating plate can be attached to its outer wall to control the internal temperature of the heating chamber 2.

[0032] The first ultrasonic mechanism 3 and the second ultrasonic mechanism 4 can be commercially available ultrasonic transmitters, with their external ends connected to a controller to adjust their transmission power. The first ultrasonic mechanism 3 and the second ultrasonic mechanism 4 are arranged opposite each other on the two inner walls of the heating chamber 2. The first ultrasonic mechanism 3 and the second ultrasonic mechanism 4 are symmetrically arranged on both sides of the transmission direction of the fiber bundle 11, and the ultrasonic wave transmission direction of the first ultrasonic mechanism 3 and the second ultrasonic mechanism 4 is perpendicular to the transmission direction of the fiber bundle 11.

[0033] The extrusion head 5 is positioned after the heating chamber 2 and extrudes the fiber bundle 11 for additive manufacturing. When the fiber bundle 11 passes through the heating chamber 2, ultrasonic waves are simultaneously emitted from both sides of the fiber bundle 11 by the first ultrasonic mechanism 3 and the second ultrasonic mechanism 4. This causes the fiber bundle 11 to be unbundled under the action of the ultrasonic waves, and the fiber filaments 111 inside are dispersed. However, the fiber bundle 11 is not broken at this time; it is just that the fiber filaments 111 inside are in a dispersed and dissociated state. At the same time, the ultrasonic waves also guide the resin material 21 molecules to flow in the heating chamber 2, so that the resin material 21 molecules uniformly wrap each fiber filament 111. Then, when the extrusion head 5 extrudes the molten resin material 21 and the fiber bundle 11 at the same time for additive manufacturing, the fiber filaments 111 and the resin material 21 molecules are fully and effectively combined to improve product performance.

[0034] exist Figure 1 In a preferred embodiment shown, a third ultrasonic mechanism 6 is also included. The third ultrasonic mechanism 6 also uses a commercially available ultrasonic transmitter, and its external end is connected to a controller to adjust its transmission power. The third ultrasonic mechanism 6 is disposed in the heating chamber 2 near the inner wall of the extrusion head 5. The third ultrasonic mechanism 6 emits ultrasonic waves in the opposite direction of the transmission of the fiber bundle 11. Therefore, the ultrasonic emission direction of the third ultrasonic mechanism 6 is perpendicular to that of the first ultrasonic mechanism 3 or the second ultrasonic mechanism 4, which ensures that the ultrasonic waves cover all parts of the entire fiber bundle 11 and effectively affect the dispersion state of the fiber bundle 11 and the flow state of the resin material 21 from multiple directions.

[0035] exist Figure 3 In a preferred embodiment shown, the system further includes a second feeding mechanism 7, a robotic arm 8, and a printing plane 9.

[0036] The second feeding mechanism 7 delivers resin wire 71 into the heating chamber 2.

[0037] The robotic arm 8 is equipped with a first feeding mechanism 1, a heating chamber 2, an extruder head 5, and a second feeding mechanism 7. The robotic arm 8 drives the first feeding mechanism 1, the heating chamber 2, the extruder head 5, and the second feeding mechanism 7 to move synchronously in multiple axes relative to the printing plane 9. The first feeding mechanism 1 and the second feeding mechanism 7 are typically spools wound with fiber bundles 11 or resin filaments 71, with the ends of the filaments pulled out for use. Guide wheels can be installed on the robotic arm 8 to guide the filament transmission. The heating chamber 2 and the extruder head 5 are mounted on the end of the robotic arm 8, and a laser is also installed at the end of the robotic arm 8 to sinter and solidify the raw material extruded by the extruder head 5. The flexible multi-axis movement of the robotic arm 8 can drive the extruder head to move freely in space at a suitable speed. At the same time, the heating chamber 2 and the extruder head 5 are both mounted on the robotic arm 8 and move synchronously, allowing the robotic arm 8 to accurately adjust the fiber conveying speed of the continuous fiber conveying equipment according to a preset program, so that it matches the ultrasonic emission power of each ultrasonic mechanism in the heating chamber 2 in real time.

[0038] exist Figure 3 In a preferred embodiment shown, when the robotic arm 8 drives the extrusion head 5 to extrude the fiber bundle 11 onto the printing plane 9, the fiber bundle 11 itself has a certain degree of flexibility. After its end contacts the printing plane 9 and is sintered onto the printing plane 9 by laser, the movement of the robotic arm will cause the fiber bundle 11 to be stretched, resulting in a certain degree of bending or twisting of the fiber bundle 11 itself. This bending or twisting state can be regarded as a change in the tilt angle of the fiber bundle 11 relative to the printing plane 9. This leads to the ultrasonic assistance of the two ultrasonic mechanisms on the front and rear sides of the fiber bundle 11. The effects will differ, thus affecting the bonding effect between the fiber filament 11 and the resin material 21 molecules. In this embodiment, the first ultrasonic mechanism 3 and the second ultrasonic mechanism 4 are respectively set on the front and rear sides of the moving direction of the extrusion head 5. When the extrusion head 5 moves in a certain direction under the drive of the robotic arm 8, the bending or twisting of the fiber bundle 11 will change the angle between the fiber bundle 11 and the ultrasonic emission direction of the two ultrasonic mechanisms. Therefore, the power of the first ultrasonic mechanism 3 and the second ultrasonic mechanism 4 also needs to change accordingly to ensure the ultrasonic-assisted effect of fully bonding the fiber bundle 11 and the resin material 21.

[0039] exist Figure 1 In a preferred embodiment shown, the relationships between the power of the first ultrasonic mechanism 3 and the second ultrasonic mechanism 4 and the tilt angle of the fiber bundle 11 are as follows:

[0040]

[0041]

[0042] Wherein, P0 is the initial power of the first ultrasonic mechanism 3 or the second ultrasonic mechanism 4, typically 40–100 W; ΔPmax The maximum power variation of the first ultrasonic mechanism 3 or the second ultrasonic mechanism 4 is typically 5–10 W, and θ is the tilt angle of the fiber bundle 11. By adjusting the power of the two ultrasonic mechanisms on the left and right sides of the fiber bundle 11 in real time, the problem of uneven distribution of resin material 21 inside the fiber bundle 11 is avoided, and uniform encapsulation of resin material 21 molecules and fiber filaments 111 is achieved.

[0043] exist Figure 1 In a preferred embodiment shown, the power of the third ultrasonic mechanism 6 is usually kept constant at P0 because the ultrasonic direction of the third ultrasonic mechanism 6 is consistent with the tilt direction of the extruder head 5, and therefore does not have a significant difference from the tilt direction of the fiber bundle 11.

[0044] exist Figure 1 In a preferred embodiment shown, the extrusion speed of the extruder 5 is directly proportional to the power of the third ultrasonic mechanism 6. Controlling the extrusion speed of the extruder 5 essentially controls the printing speed of additive manufacturing. Due to the varying molding requirements of different parts of the preform during printing, the printing speed changes. If the printing speed is too high, the fiber bundle 11 and resin material 21 may not fully bond under ultrasonic assistance, resulting in a significant increase in the fiber volume fraction in the printed preform, thus affecting the final performance of the product. Therefore, this embodiment adjusts the initial power of each ultrasonic mechanism in real time according to the printing speed, ensuring that the fiber volume fraction in the preform remains within a reasonable and balanced range during the printing process, thereby guaranteeing the product molding effect.

[0045] exist Figure 1 In a preferred embodiment shown, the fiber bundle 11 is made of continuous carbon fiber or continuous silicon carbide fiber material, and the number of fibers inside is 1K, 3K, etc.; the resin wire 71 is made of thermoplastic resin, specifically including polylactic acid (PLA), polycarbonate (PC), polyetheretherketone (PEEK), etc., and the wire diameter of the resin wire 71 is generally 1.75mm.

[0046] like Figure 1 As shown, combined with Figure 2 and Figure 3 A robotic additive manufacturing method for the continuous preparation of ultrasonic-assisted composite fiber ceramic composites, employing a robotic additive manufacturing apparatus for the continuous preparation of ultrasonic-assisted composite fiber ceramic composites according to any of the above embodiments, includes the following steps:

[0047] Step one: The first feeding mechanism 1 is activated to output fiber bundles 11, and the second feeding mechanism 7 is activated to feed resin wires 71 into the heating chamber 2. The heating chamber 2 melts the resin wires 71 to obtain molten resin material 21. Specifically, a three-dimensional model of the sample is first established. After the three-dimensional model is sliced, the motion trajectory of the additive manufacturing equipment of the robotic arm 8 is set according to the slices, and the slice data is converted into control parameters of the robotic arm 8. Then, the fiber bundles 11 and resin wires 71 are loaded into the first feeding mechanism 1 and the second feeding mechanism 7 respectively, and the transmission device is activated to start feeding.

[0048] Step two: Simultaneously activate the first ultrasonic mechanism 3, the second ultrasonic mechanism 4, and the third ultrasonic mechanism 6 to emit ultrasonic waves. The fiber bundle 11 passes through the heating chamber 2 and is subjected to ultrasonic waves, causing the fiber bundle 11 to be broken apart and its individual fibers 111 to separate from each other, so that the resin material 21 uniformly coats each fiber 111. Specifically, the extruder head 5 has a diameter of 0.8–2.0 mm, a printing speed of 60–600 mm / min, a line spacing of 0.8–4.0 mm, a slice layer height of 0.2–0.5 mm, and a printing temperature of the resin material 21 of 180℃–400℃.

[0049] Step 3: The extruder 5 extrudes the fiber bundle 11, and the robotic arm 8 drives the extruder 5 to use the extruded fiber bundle 11 for additive manufacturing and printing to obtain a preform. The fiber volume fraction in the preform is 20 vol% to 60 vol%. The extrusion speed of the extruder 5 is matched with the power of the third ultrasonic mechanism 6 in real time.

[0050] exist Figure 1In a preferred embodiment, the process further includes step four: placing the preform in a thermosetting phenolic resin solution and vacuum impregnating it, followed by drying, curing, and high-temperature pyrolysis to allow the thermoplastic resin and thermosetting phenolic resin to pyrolyze under high temperature conditions, thereby solidifying the phenolic resin and encapsulating the preform. At this point, only trace amounts of pyrolytic carbon remain outside the fiber bundles, forming a preform. During this process, the precursor on the fiber surface simultaneously pyrolyzes, forming an interface layer on the fiber surface. The preform is then subjected to subsequent ceramicization treatment to fill the pores between the fibers with a silicon carbide ceramic phase, enabling the fiber bundles to form a good bond with the interface layer on the fiber surface, thus preparing a continuous fiber-reinforced silicon carbide composite fiber material. Specifically, the thermosetting phenolic resin solution is a mixture of powdered phenolic resin and anhydrous ethanol at a mass ratio of 1:1, and the phenolic resin type is 2133. The vacuum impregnation conditions are 30–90 min for a vacuum degree ≤0.02 MPa. Drying and curing involve placing the preform in a drying oven and holding it at 150–200℃ for 30–60 min to solidify the phenolic resin solution and encapsulate the preform. High-temperature pyrolysis refers to placing the sample in a tube furnace or box furnace with an argon protective atmosphere and heating it to 850℃ at a heating rate of 5℃ / min–20℃ / min for 60–180 min. Subsequent ceramicization treatments include precursor impregnation pyrolysis (PIP), chemical vapor infiltration (CVI), and reactive silicon infiltration (RMI). The PIP method involves placing the preform in a precursor impregnation solution, performing vacuum impregnation and curing, and then pyrolyzing the preform at high temperature to generate ceramics. The specific steps include: ① Using commercially available polycarbosilane as a silicon carbide precursor, which is generally a yellow blocky solid, grinding it into powder and mixing it with a solvent to prepare an impregnation solution. The mass ratio of polycarbosilane to solvent is 1:1 to 2:1, and the solvent is xylene, divinylbenzene, etc.; ② Immersing the preform in the impregnation solution and performing vacuum impregnation, with a vacuum degree ≤0.02MPa and an impregnation time of 60min; ③ Drying the impregnated preform at 180℃ for 120min; ④ Heating the dried preform to 1000-1200℃ under argon protection and holding it at that temperature for 120min to allow the polycarbosilane to decompose and generate a silicon carbide ceramic phase; ⑤ Repeating the above steps 5-10 times until the sample dry weight growth rate is <1%; The above CVI method involves placing the preform in a vacuum reaction chamber, introducing a reaction gas and a protective gas, allowing the reaction gas to penetrate between the fibers, and causing a chemical reaction on the fiber surface under high temperature conditions to generate a silicon carbide ceramic phase. The protective gas mentioned above is generally argon, and the reaction gases include carrier gas hydrogen and silicon carbide precursor gas, generally methyltrichlorosilane. The reaction temperature is 1000-1300℃. The RMI method described above involves introducing a carbon source into the preform using an impregnation pyrolysis method, and then, under high temperature and vacuum conditions, allowing liquid silicon and gaseous silicon to infiltrate into the residual pores and react with carbon to generate a silicon carbide ceramic phase.The method of introducing a carbon source is generally to cyclically impregnate a high residual carbon filter resin and then pyrolyze it, with a reaction temperature of 1650℃ and a vacuum degree of 1-24 Pa.

[0051] In order to verify whether the printing speed of additive manufacturing and the initial power of each ultrasonic mechanism affect the performance of the printed product, the present invention prepared the following test examples 1 to 5 and comparative examples 1 and 2 for comparison, and compared and analyzed the fracture toughness and bending strength data of each sample.

[0052] The sample in Test Example 1 was prepared using the following method:

[0053] (1) Establish a three-dimensional model of the sample, slice the motion trajectory of the additive manufacturing equipment of the robotic arm 8, and convert the slicing data into control parameters of the robotic arm 8; place continuous fiber filaments (i.e., fiber bundles 11) and thermoplastic resin (using polycarbonate (PC), i.e., resin filaments 71) on the additive manufacturing equipment of the robotic arm 8, and preheat the heating chamber 2 in advance. The thermoplastic resin and continuous carbon fiber material are synchronously transferred to the heating chamber 2 through the transmission device. The resin diameter is 1.75mm and the number of fiber bundles is 1K; set the forming process parameters of the additive manufacturing equipment of the robotic arm 8 as follows: extruder head 5 diameter 1.3mm, printing speed 200mm / min, and simultaneously turn on each ultrasonic mechanism. The initial power P0 of the ultrasonic assistance is 40W, and the variable maximum power ΔP max With a power rating of 10W, a wiring spacing of 1.0mm, a layer height of 0.3mm, and a printing temperature of 270℃ for the resin filament 71, the heating chamber 2 heats up to melt the thermoplastic resin material 21. The molten resin and fiber bundle 11 are then extruded together onto the printing plane 9 via a transmission device. The additive manufacturing equipment, controlling the robotic arm 8, moves according to a set trajectory to prepare a continuous fiber-reinforced resin-based composite fiber material sample, i.e., a preform with a fiber volume fraction of 40 vol%.

[0054] (3) The preform was placed in a thermosetting phenolic resin solution and impregnated under vacuum for 60 min at a vacuum degree of 0.02 MPa. The preform was then placed in a drying oven and dried and cured at 180°C for 60 min to allow the phenolic resin solution to solidify and encapsulate the preform. The sample was then placed in a tube furnace or box furnace under an argon protective atmosphere for high-temperature pyrolysis. The temperature was increased to 850°C at a rate of 10°C / min and held for 90 min to allow the thermoplastic resin polycarbonate (PC) to pyrolyze under high-temperature conditions, leaving only trace amounts of pyrolytic carbon to form a preform.

[0055] (4) The preform undergoes subsequent ceramicization treatment, specifically precursor impregnation pyrolysis (PIP) treatment. ① Commercially available polycarbosilane, a yellow blocky solid, is used as the silicon carbide precursor. It is first ground into powder and mixed with a solvent to prepare an impregnation solution. The mass ratio of polycarbosilane to solvent is 1.5:1, and xylene is used as the solvent. ② The preform is immersed in the impregnation solution and vacuum impregnated at a vacuum degree of 0.02 MPa for 60 min. ③ The impregnated preform is dried at 180°C for 120 min. ④ The dried preform is heated to 1100°C under argon protection and held for 120 min to allow the polycarbosilane to pyrolyze and generate a silicon carbide ceramic phase. ⑤ The above steps are repeated 10 times until the sample dry weight growth rate is <1%. This fills the pores between fibers with the silicon carbide ceramic phase and forms a good bond with the interface layer on the fiber surface, thus preparing a continuous fiber-reinforced silicon carbide composite material.

[0056] The difference between Experiment 2 and Experiment 1 is that the printing speed is 400 mm / min and the initial power of each ultrasonic mechanism is 60 W.

[0057] The difference between Experiment 3 and Experiment 1 is that the printing speed is 600 mm / min and the initial power of each ultrasonic mechanism is 80 W.

[0058] The difference between Experiment 4 and Experiment 1 is that the printing speed is 400 mm / min, the initial power of each ultrasonic mechanism is 60 W, and the number of fibers in fiber bundle 11 is 3K.

[0059] The difference between Experiment 5 and Experiment 1 is that the printing speed is 400 mm / min, the initial power of each ultrasonic mechanism is 60 W, and polyetheretherketone (PEEK) is used as the resin material 21.

[0060] The performance test results of each sample are shown in Table 1 below:

[0061] Table 1

[0062]

[0063]

[0064] Comparative experiments 1 to 3 reveal that, with the number of fibers 111 in the fiber bundle 11 remaining constant, as the printing speed increases, the initial power of each ultrasonic mechanism also increases. The sample performance initially improves and then decreases, but the difference is not significant. This is presumably because when the ultrasonic power is low, ultrasonic assistance cannot effectively achieve uniform mixing and coating of the fibers 111 and resin material 21 molecules; while at higher ultrasonic power, the resin material 21 molecules may have difficulty binding tightly to the fibers 111, thus affecting the uniform coating effect. Excessive ultrasonic power may even break the fibers 111, affecting the normal extrusion of the fiber bundle 11 and resin material 21 through the extruder 5. Comparative experiments 2 and 4 show that a sudden increase in the number of fibers 111 in the fiber bundle 11 also makes it difficult for ultrasonic assistance to effectively achieve uniform mixing and coating of the fibers 111 and resin material 21 molecules, resulting in a fiber volume fraction in the preform that is outside the reasonable range, thus weakening the performance of the printed product. By comparing test examples 2 and 5, it can be found that the choice of resin material 21 generally does not have a significant impact on the performance of the printed product.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A robotic additive manufacturing device for the continuous preparation of ultrasonic-assisted composite fiber ceramic composites, characterized in that, include: The first feeding mechanism (1) outputs a fiber bundle (11); A heating chamber (2) is located after the first feeding mechanism (1) and is filled with molten resin material (21); The first ultrasonic mechanism (3) and the second ultrasonic mechanism (4) are disposed opposite to each other on the two inner walls of the heating cavity (2); An extrusion head (5) is positioned behind the heating chamber (2) and extrudes fiber bundles (11) for additive manufacturing; The third ultrasonic mechanism (6) is located on the inner wall of the heating chamber (2) near the extrusion head (5); The second feeding mechanism (7) feeds resin wire (71) into the heating chamber (2); A robotic arm (8) is provided with a first feeding mechanism (1), a heating chamber (2), an extrusion head (5) and a second feeding mechanism (7); Print plane (9); The first ultrasonic mechanism (3) and the second ultrasonic mechanism (4) are symmetrically arranged on both sides of the transmission direction of the fiber bundle (11), and the ultrasonic emission direction of the first ultrasonic mechanism (3) and the second ultrasonic mechanism (4) is perpendicular to the transmission direction of the fiber bundle (11). When the fiber bundle (11) passes through the heating chamber (2), it is subjected to ultrasonic waves, which disperses the fiber filaments (111) inside and causes the resin material (21) to uniformly wrap each fiber filament (111). The third ultrasonic mechanism (6) emits ultrasonic waves in the opposite direction of transmission along the fiber bundle (11); The robotic arm (8) drives the first feeding mechanism (1), heating chamber (2), extruder (5) and second feeding mechanism (7) to move synchronously in multiple axes relative to the printing plane (9); when the robotic arm (8) drives the extruder (5) to extrude fiber bundles (11) on the printing plane (9), the tilt angle of the fiber bundles (11) relative to the printing plane (9) changes. The first ultrasonic mechanism (3) and the second ultrasonic mechanism (4) are respectively located on the front and rear sides of the moving direction of the extruder (5), and the power of the first ultrasonic mechanism (3) and the second ultrasonic mechanism (4) also changes accordingly.

2. The robotic additive manufacturing apparatus for continuous preparation of ultrasonic-assisted composite fiber ceramic composites according to claim 1, characterized in that: The power of the first ultrasonic mechanism (3) and the second ultrasonic mechanism (4) and the tilt angle of the fiber bundle (11) are respectively expressed as follows: Wherein, P0 is the initial power of the first ultrasonic mechanism (3) or the second ultrasonic mechanism (4), and ΔP max θ is the maximum power change of the first ultrasonic mechanism (3) or the second ultrasonic mechanism (4), and θ is the tilt angle of the fiber bundle (11).

3. The robotic additive manufacturing apparatus for continuous preparation of ultrasonic-assisted composite fiber ceramic composites according to claim 2, characterized in that: The power of the third ultrasonic device (6) is P0.

4. The robotic additive manufacturing apparatus for continuous preparation of ultrasonic-assisted composite fiber ceramic composites according to claim 3, characterized in that: The extrusion speed of the extruder (5) is directly proportional to the power of the third ultrasonic mechanism (6).

5. The robotic additive manufacturing apparatus for continuous preparation of ultrasonic-assisted composite fiber ceramic composites according to claim 1, characterized in that: The fiber bundle (11) is made of continuous carbon fiber or continuous silicon carbide fiber material, and the resin wire (71) is made of thermoplastic resin.

6. A robotic additive manufacturing method for the continuous preparation of ultrasonic-assisted composite fiber ceramic composites, characterized in that: The robotic additive manufacturing apparatus for continuous fabrication of ultrasonic-assisted composite fiber ceramic composites according to any one of claims 1 to 5 includes the following steps: Step 1: Start the first feeding mechanism (1) to output fiber bundle (11) and start the second feeding mechanism (7) to feed resin wire (71) into the heating chamber (2). The heating chamber (2) melts the resin wire (71) and obtains molten resin material (21). Step 2: Simultaneously activate the first ultrasonic mechanism (3), the second ultrasonic mechanism (4) and the third ultrasonic mechanism (6) to emit ultrasonic waves. The fiber bundle (11) passes through the heating chamber (2) and is subjected to ultrasonic waves. The fiber bundle (11) is broken apart and the individual fibers (111) inside it are separated from each other, so that the resin material (21) evenly wraps each fiber (111). Step 3: The extrusion head (5) extrudes the fiber bundle (11), and the robotic arm (8) drives the extrusion head (5) to use the extruded fiber bundle (11) for additive manufacturing and printing to obtain a preform. The extrusion speed of the extrusion head (5) is matched with the power of the third ultrasonic mechanism (6) in real time.

7. The robotic additive manufacturing method for continuous preparation of ultrasonic-assisted composite fiber ceramic composites according to claim 6, characterized in that: The process also includes step four, in which the blank is placed in a thermosetting phenolic resin solution and impregnated under vacuum, then dried and the phenolic resin is cured and encapsulated around the blank.

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