3D printing method and device for bionic multi-level spiral structure reinforced composite materials

Abstract

The present invention discloses a 3D printing method and device for bionic multi-level spiral structure reinforced composite materials. The device includes a digital continuous fiber weaving system, a molding manufacturing system and a control system. According to a predefined geometric model and an internal multi-level spiral winding fiber distribution pattern, a related three-dimensional model is established and discretized. The fiber weaving system is used to guide the continuous fiber reinforced composite wire to be woven into a multi-level bionic spiral winding structure, which is further used in a 3D printing molding system. Finally, post-processing curing molding is performed to achieve the preparation of toughened bionic composite material samples. The present invention has great application potential in key components of high-end equipment in the fields of aerospace, automobiles, ships and wind power generation.

Description

Technical Field

[0001] The present invention belongs to the field of additive manufacturing, and in particular relates to a 3D printing method and device for bionic multi-stage spiral structure reinforced composite materials. Background Art

[0002] High-end equipment in the fields of aerospace, automobiles, ships, and wind power generation usually serve in harsh environments, which requires that the materials of their key components have both high strength and high toughness. However, engineering materials often sacrifice their elongation at break and toughness to obtain high strength, and cannot achieve synergistic enhancement of strength and toughness. In nature, some material tissues of plants and animals (such as cotton and linen fibers of plants, hair and silk of animals) effectively circumvent the performance contradiction between strength and toughness, and achieve a perfect combination of high strength and high toughness. Studies have shown that these typical biostructural materials have some commonalities: they are all natural multi-level composite materials, with highly ordered fibers woven into a multi-level spiral winding structure, effectively wrapped in a softer organic matrix.

[0003] However, due to the limitations of design methods and manufacturing processes, structural innovation and manufacturing technology for toughened materials have long been in the exploratory stage. The hierarchical spiral structure in nature provides new manufacturing ideas for the design of toughened bionic composite materials, but there is still a lack of engineering technical means. Summary of the invention

[0004] In order to solve the problems existing in the above-mentioned background technology, the present invention provides a 3D printing method and device for bionic multi-level spiral structure reinforced composite materials, which can realize the multi-level spiral winding of continuous fibers of the reinforcing phase in the composite material, thereby synergistically enhancing the strength and toughness of the material.

[0005] The 3D printing device of the bionic multi-stage spiral structure reinforced composite material of the present invention comprises a molding manufacturing system, a digital continuous fiber weaving system and a control system;

[0006] The digital continuous fiber weaving system includes 1st level, 2nd level, 3rd level...nth level winding systems;

[0007] The basic winding system unit of the digital continuous fiber weaving system is composed of two material conveying systems and an encoding winder;

[0008] The material conveying system comprises an extrusion head fixing device, a system support, an upper-level wire (fiber) conveyor, a fluid matrix conveying device and a compounder; wherein the extrusion head fixing device, the upper-level wire (fiber) conveyor, the fluid matrix conveying device and the compounder are fixed on the system support; the upper-level wire (fiber) conveyor is located above the compounder; the fluid matrix conveying device is directly connected to the compounder; and the extrusion head fixing device contains a composite wire output head.

[0009] The coding winder comprises a wire guide and a winding device;

[0010] The molding manufacturing system includes a three-dimensional motion system, a multi-stage bionic winding composite wire conveyor, an extrusion device, and a composite wire cutting device; wherein the three-dimensional motion system can control the movement of the molding manufacturing system in three directions: X, Y, and Z; the multi-stage bionic winding composite wire conveyor is located above the extrusion device; the composite wire cutting device is fixed to the extrusion device, can move up and down along the inclined direction of the extrusion device, and can achieve 180° rotation shearing.

[0011] The 3D printing method of the bionic multi-level spiral structure reinforced composite material of the present invention comprises the following steps:

[0012] Step 1: The matrix material consists of a polymer and a volatile organic solvent

[0013] The volume ratio of the polymer is 44-78 vol.%, and the volume ratio of the organic solvent is 22-56 vol.%;

[0014] The polymer is composed of one or more materials selected from the group consisting of polylactic acid, polyethylene, and polymethyl methacrylate;

[0015] The organic solvent is a volatile solvent such as acetone or dimethylformamide;

[0016] The matrix material is prepared by adding a polymer into an organic solvent in three equal portions, completely dissolving and mixing, and setting aside after preparation. The viscosity of the obtained material is controlled at 2600-5800 Pa·s;

[0017] The continuous reinforcing fibers are composed of one or more of glass fibers, carbon fibers, aramid fibers, polyaramid fibers, and very fine metal wires;

[0018] Step 2: 3D printing of multi-level spiral winding structure reinforced bionic composite materials

[0019] Step 1: Construction of three-dimensional model: According to the predefined geometric model of the toughened bionic composite material and the internal multi-level spiral winding fiber distribution pattern, a relevant three-dimensional model is established, and then the model is discretized to obtain the relevant weaving machine motion code, extrusion head motion path and related process parameter settings.

[0020] Step 2: Multi-level bionic winding structure motion encoding

[0021] According to the number of levels and winding methods of the bionic structure in the bionic composite material model, the working mode of the digital continuous fiber weaving system is determined, including the number and process position of the material conveyors involved in the work of each level of the winding system, the fiber bundle conveying speed, the rotating output speed and direction (clockwise or counterclockwise) of the encoding winder, and the matrix material conveying speed;

[0022] Step 3: Pre-grouping of continuous fiber bundles

[0023] Connecting to the primary (1st level) fiber conveyor, the fiber bundle is pushed into the material compounder by the fiber conveyor, and the matrix material is conveyed into the compounder by the fluid matrix conveyor, and the pre-treated composite material system is extruded from the nozzle;

[0024] Step 4: Connect the continuous fiber material extruded from the primary conveyor to the winding encoder through the wire guide, and perform primary bionic structure fiber winding encoding according to the rotation speed and direction of the winding device obtained in step 2;

[0025] Step 5: According to the levels and weaving procedures of the predefined bionic composite materials in steps 1 and 2, steps 3 to 4 are repeated to prepare 2-level, 3-level...n-level bionic fiber winding structures;

[0026] Step 6: According to the extruder motion path and related process parameter settings of the predefined three-dimensional model obtained in step 1, the multi-level bionic fiber filaments of the digital continuous fiber weaving system are used in the molding manufacturing system to print and form the three-dimensional solid first-layer structure;

[0027] Step 7: When the printing wire needs to be disconnected due to changing layers or directions, the fiber wire is cut and disconnected by using a cutting device;

[0028] Step 8: Repeat steps 6 to 7 to print the second, third, and nth layers of the three-dimensional solid structure until the model is printed;

[0029] Step 3: Post-processing of bionic multi-stage fiber reinforced composite 3D samples

[0030] The printed three-dimensional solid sample is placed in a drying oven. The drying temperature needs to be 15°C lower than the glass transition temperature of the thermoplastic polymer. It is usually set at 40-60°C for 0.5-48 hours, and the organic solvent in the sample is completely volatilized. Finally, it is taken out of the drying oven and cooled at room temperature to achieve the printing of a strong and tough bionic composite three-dimensional sample.

[0031] In the second step, the motion encoding of the multi-level bionic winding structure, the n-th level material conveying speed is the output speed of the upper level (n-1 level) material spiral winding system encoder.

[0032] In the second step, regarding the motion encoding of each level of winding system, the fiber bundle conveying speed is consistent with the matrix material conveying speed (defined as νmm / s); the rotation direction of the encoding winder is clockwise or counterclockwise; the rotation linear speed of the encoding winder must maintain a certain difference with the matrix material conveying speed, and the speed range is (ν-5)-(ν+5)mm / s.

[0033] Beneficial results of the present invention:

[0034] The present invention designs a 3D printing method and device for bionic multi-stage spiral structure reinforced composite materials based on the process principle of 3D printing. Different from the single fiber bundle structure reinforcement in the traditional continuous fiber reinforced composite material 3D printing technology, the method and device of the present invention can realize the manufacturing and printing of bionic multi-stage spiral winding composite wires. While achieving the synergistic enhancement of the strength and toughness of the printed samples, the degree of reinforcement and toughness is greatly improved. In addition, the matrix material used in the present invention is formed by a uniform mixture of polymer and organic solvent. The organic solvent in the polymer evaporates slowly during the printing process. After the printing is completed, the post-processing further effectively removes the organic solvent. This method is conducive to improving the interlayer bonding strength in the traditional FDM printing process, effectively improving the material strength, and enhancing the engineering practicality of the printed samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is an overall schematic diagram of the 3D printing device of the bionic multi-stage spiral structure reinforced composite material involved in the present invention.

[0036] Figure 2 It is a structural schematic diagram of a material conveying system in a basic structural unit of a digital continuous fiber weaving system in a 3D printing system involved in the present invention;

[0037] Figure 3 It is a structural schematic diagram of a coding winder in a basic structural unit of a digital continuous fiber weaving system in a 3D printing system involved in the present invention;

[0038] Figure 4 It is a schematic diagram of the structure of the molding manufacturing system in the 3D printing system involved in the present invention;

[0039] Figure 5 It is a bionic composite silk material structure of unidirectional winding and weaving realized by a digital continuous fiber weaving system in a specific embodiment of the present invention;

[0040] Figure 6 It is a bionic composite silk material structure of bidirectional winding braiding realized by a digital continuous fiber braiding system in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0042] See also Figures 1 to 6 , a 3D printing device for bionic multi-stage spirally wound fiber reinforced composite materials, comprising a molding manufacturing system 1, a digital continuous fiber weaving system 2 and a control system 3;

[0043] The digital continuous fiber weaving system 2 includes 1st level, 2nd level, 3rd level...nth level winding systems;

[0044] The basic winding system unit of the digital continuous fiber weaving system 2 is composed of two material conveying systems and an encoding winder;

[0045] The material conveying system comprises an extrusion head fixing device 4, a system support 5, an upper-level wire (fiber) conveyor 6, a fluid matrix conveying device 7 and a compounder 8; wherein the extrusion head fixing device 4, the upper-level wire (fiber) conveyor 6, the fluid matrix conveying device 7 and the compounder 8 are fixed on the system support 5; the upper-level wire (fiber) conveyor 6 is located above the compounder (8); the fluid matrix conveying device 7 is directly connected to the compounder 8; and the extrusion head fixing device 4 contains a composite wire output head.

[0046] The coding winder comprises a wire guide 9 and a winding device 10;

[0047] The molding manufacturing system 1 includes a three-dimensional motion system 11, a multi-stage bionic winding composite wire conveyor 12, an extrusion device 13, and a composite wire cutting device 14; wherein the three-dimensional motion system 11 can control the movement of the molding manufacturing system in three directions: X, Y, and Z; the multi-stage bionic winding composite wire conveyor 12 is located above the extrusion device 13; the composite wire cutting device 14 is fixed to the extrusion device 13, can move up and down along the inclined surface of the extrusion device 13, and can achieve 180° rotation shearing.

[0048] The 3D printing method of bionic multi-level spiral structure reinforced composite material has the following specific steps:

[0049] Example 1

[0050] 1. 57 vol.% polylactic acid and 43 vol.% acetone were uniformly mixed and dissolved as the matrix material, and continuous carbon fiber bundles were used as the reinforcement material;

[0051] 2. According to the predefined geometric model of the toughened bionic composite material and the internal multi-level spiral winding fiber distribution pattern, a relevant three-dimensional model is established, and then the model is discretized to obtain the relevant braiding machine motion code, extruder head motion path and related process parameter settings;

[0052] 3. See Figure 5According to the level and winding mode of the bionic structure in the bionic composite material model, it is determined that the three-level winding system is involved in the winding coding. The primary winding system includes 4 basic winding units, the secondary winding system includes 2 basic winding units, and the tertiary winding system includes 1 basic winding unit; the rotation direction of the winding encoders of the primary, secondary and tertiary winding systems is clockwise, the fiber conveying speed of the primary material conveying system is consistent with the matrix material conveying speed, both of which are 8 mm / s, and the output speed of the winding encoder is 7 mm / s;

[0053] 4. Pre-group the continuous fiber bundles, connect them to the primary (1st level) fiber conveyor, push the fiber bundles into the material compounder by using the fiber conveyor, and at the same time, convey the matrix material into the compounder from the conveying port, and extrude the pre-treated composite material system from the nozzle;

[0054] 5. The continuous fiber material extruded from the primary conveyor is connected to the winding encoder through the wire guide, and the primary bionic structure fiber winding encoding is performed according to the encoder rotation speed and direction obtained in step 2;

[0055] 6. According to the number of levels and weaving process of the predefined bionic multi-level composite materials in steps 1 and 2, repeat steps 3 to 4 to prepare 2-level and 3-level bionic fiber winding structures;

[0056] 7. According to the extruder head motion path and related process parameter settings of the predefined three-dimensional model obtained in step 1, the multi-level bionic fiber filaments of the digital continuous fiber weaving system are used in the molding manufacturing system to print and mold the three-dimensional solid first-layer structure;

[0057] 8. When the printing wire needs to be disconnected for changing layers or directions, the fiber wire is cut and disconnected by using the cutting device;

[0058] 9. Repeat steps 6 to 7 to print the second, third, and nth layers of the three-dimensional solid structure until the model is printed;

[0059] 10. Place the printed three-dimensional solid sample in a drying oven, set the drying temperature at 50°C for 10 hours, and wait until the organic solvent in the sample is completely volatilized. Finally, take it out of the drying oven and cool it at room temperature to achieve the printing of strong and tough bionic composite three-dimensional samples.

[0060] Embodiment 2:

[0061] 1. 63 vol.% polyethylene and 37 vol.% acetone were uniformly mixed and dissolved as the matrix material, and continuous glass fiber bundles were used as the reinforcement material;

[0062] 2. According to the predefined geometric model of the toughened bionic composite material and the internal multi-level spiral winding fiber distribution pattern, a relevant three-dimensional model is established, and then the model is discretized to obtain the relevant braiding machine motion code, extruder head motion path and related process parameter settings;

[0063] 3. See Figure 6 According to the level and winding mode of the bionic structure in the bionic composite material model, it is determined that the three-level winding system is involved in the winding coding. The primary winding system includes 4 basic winding units, the secondary winding system includes 2 basic winding units, and the 3rd winding system includes 1 basic winding unit. The rotation directions of the winding encoders of the primary, secondary, and 3rd winding systems are clockwise-counterclockwise-clockwise, respectively. The fiber conveying speed of the primary material conveying system is consistent with the matrix material conveying speed, both of which are 10 mm / s. The output speed of the winding encoder is 8 mm / s.

[0064] 4. Pre-group the continuous fiber bundles, connect them to the primary (1st level) fiber conveyor, push the fiber bundles into the material compounder by using the fiber conveyor, and at the same time, convey the matrix material into the compounder from the conveying port, and extrude the pre-treated composite material system from the nozzle;

[0065] 5. Connect the continuous fiber material extruded from the primary conveyor to the winding encoder through the wire guide, and perform primary bionic structure fiber winding encoding according to the encoder rotation speed and direction obtained in step 2;

[0066] 6. According to the number of levels and weaving process of the predefined bionic multi-level composite materials in steps 1 and 2, repeat steps 3 to 4 to prepare 2-level and 3-level bionic fiber winding structures;

[0067] 7. According to the extruder head motion path and related process parameter settings of the predefined three-dimensional model obtained in step 1, the multi-level bionic fiber filaments of the digital continuous fiber weaving system are used in the molding manufacturing system to print and mold the three-dimensional solid first-layer structure;

[0068] 8. When the printing wire needs to be disconnected for changing layers or directions, the fiber wire is cut and disconnected by using the cutting device;

[0069] 9. Repeat steps 6 to 7 to print the second, third, and nth layers of the three-dimensional solid structure until the model is printed;

[0070] 10. Place the printed three-dimensional solid sample in a drying oven, set the drying temperature at 45°C for 12 hours, and wait until the organic solvent in the sample is completely volatilized. Finally, take it out of the drying oven and cool it at room temperature to achieve the printing of strong and tough bionic composite three-dimensional samples.

Claims

1. A 3D printing method for bionic multi-level spiral structure reinforced composite materials, characterized by: The 3D printing device for bionic multi-level spiral structure reinforced composite material comprises a molding manufacturing system (1), a digital continuous fiber weaving system (2) and a control system (3); The digital continuous fiber weaving system (2) comprises 1st level, 2nd level, 3rd level, ... nth level winding systems; The basic winding system unit of the digital continuous fiber weaving system (2) is composed of two material conveying systems and an encoding winder; The material conveying system comprises an extrusion head fixing device (4), a system support (5), an upper-level silk fiber conveyor (6), a fluid matrix conveying device (7) and a compounder (8); wherein the extrusion head fixing device (4), the upper-level silk fiber conveyor (6), the fluid matrix conveying device (7) and the compounder (8) are fixed on the system support (5); the upper-level silk fiber conveyor (6) is located above the compounder (8); the fluid matrix conveying device (7) is directly connected to the compounder (8); the extrusion head fixing device (4) contains a composite silk output head; The encoding winder comprises a wire guide (9) and a winding device (10); The molding manufacturing system (1) comprises a three-dimensional motion system (11), a multi-stage bionic winding composite wire conveyor (12), an extrusion device (13), and a composite wire cutting device (14); wherein the three-dimensional motion system (11) controls the motion of the molding manufacturing system in three directions, namely, X, Y, and Z; the multi-stage bionic winding composite wire conveyor (12) is located above the extrusion device (13); and the composite wire cutting device (14) is fixed to the extrusion device (13), moves up and down along the inclined surface direction of the extrusion device (13), and can realize 180° rotation shearing; The following steps are involved: Step 1: Select and prepare materials The matrix material consists of a polymer and a volatile organic solvent; The volume ratio of the polymer is 44-78 vol.%, and the volume ratio of the organic solvent is 22-56 vol.%; The polymer is composed of one or more materials selected from polylactic acid, polyethylene, and polymethyl methacrylate. The organic solvent is a volatile solvent such as acetone or dimethylformamide; The matrix material is prepared by adding a polymer into an organic solvent in three equal portions, completely dissolving and mixing, and setting aside after preparation. The viscosity of the obtained material is controlled at 2600-5800 Pa•s; The continuous reinforcing fibers include one or more of glass fibers, carbon fibers, aramid fibers, polyaramid fibers, and very fine metal wires; Step 2: 3D printing multi-level spiral winding structure reinforced bionic composite materials Step 1: Construction of 3D model According to the predefined geometric model of the toughened bionic composite material and the internal multi-level spiral winding fiber distribution pattern, a related three-dimensional model is established, and then the model is discretized to obtain the related braiding machine motion code, extruder head motion path and related process parameter settings; Step 2: Multi-level bionic winding structure motion encoding According to the number of levels and winding methods of the bionic structure in the bionic composite material model, the working mode of the digital continuous fiber weaving system is determined, including the number and process position of the material conveyors involved in the winding system at each level, the fiber bundle conveying speed, the rotating output speed and direction of the encoding winder, and the matrix material conveying speed; Step 3: pre-grouping the continuous fiber bundles, connecting them to the first-level fiber conveyor, and using the upper-level silk fiber conveyor (6) to push the fiber bundles into the material compounder (8), while at the same time, the matrix material is conveyed into the compounder (8) by the fluid matrix conveying device (7), and the pre-treated composite material system is extruded from the nozzle; Step 4: Connect the continuous fiber material extruded from the primary conveyor to the winding encoder through the wire guide (9), and perform primary bionic structure fiber winding encoding according to the rotation speed and direction of the winding device (10) obtained in step 2; Step 5: According to the levels and weaving procedures of the predefined bionic composite materials in steps 1 and 2, steps 3 to 4 are repeated to prepare 2-level, 3-level...n-level bionic fiber winding structures; Step 6: Based on the extruder motion path and related process parameter settings of the predefined three-dimensional model obtained in step 1, the multi-level bionic fiber filaments of the digital continuous fiber weaving system (2) are used in the molding manufacturing system (1) to print and mold the three-dimensional solid first layer structure; Step 7: When it is necessary to change layers or change the direction of printing filaments and cut them, the fiber filaments are cut and cut by using a cutting device (14); Step 8: Repeat steps 6 to 7 to print the second, third, and nth layers of the three-dimensional solid structure until the model is printed; Step 3: Post-processing of bionic multi-stage fiber reinforced composite 3D samples The printed three-dimensional solid sample is placed in a drying oven. The drying temperature needs to be 15°C lower than the glass transition temperature of the thermoplastic polymer, usually set at 40-60°C, and the time is 0.5-48h, based on the complete evaporation of the organic solvent in the sample. Finally, it is taken out of the drying oven and cooled at room temperature to achieve the printing of strong and tough bionic composite three-dimensional samples.

2. The 3D printing method of the bionic multi-level spiral structure reinforced composite material according to claim 1, characterized in that: In the second step, regarding the motion encoding of the multi-level bionic winding structure, the conveying speed of the n-th level material is consistent with the output speed of the encoder of the upper n-1-level material spiral winding system.

3. The 3D printing method of the bionic multi-level spiral structure reinforced composite material according to claim 1, characterized in that: In the second step, regarding the motion encoding of each level of winding system, the fiber bundle conveying speed is consistent with the matrix material conveying speed, defined as ν mm / s; the rotation direction of the encoding winder is clockwise or counterclockwise; the rotation linear speed of the encoding winder maintains a certain difference with the matrix material conveying speed, and the speed range is (ν-5)-(ν+5) mm / s.

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