A kind of composite 3D printing device for realizing Z direction connection effect with short fiber

Abstract

A 3D printing device for composite materials that achieves a Z-axis crosslinking effect using short fibers includes a yarn spreading device, a microwave processing device, an external guide wheel, an ultrasonic device, a resin extruder, a magnetic field device, and a 3D printing device arranged sequentially. Continuous fibers processed by the yarn spreading device sequentially enter the 3D printing device through the microwave processing device, the external guide wheel, the resin extruder, and the magnetic field device. The yarn spreading device consists of a material roll, a guide wheel, a rubber-coated wheel assembly, a fixing plate, an air-blowing clamp, and an air-blowing pipe. In the printing process, this invention utilizes a magnetic field to orient the short-cut carbon fibers. By using a rotating magnetic field, the spiral arrangement of the short-cut carbon fibers in the resin can be effectively controlled, improving the mechanical properties of the composite material reinforced with both long and short fibers.

Description

Technical Field

[0001] This invention relates to the field of fiber-reinforced thermoplastic resin composite materials technology, and specifically to a composite material 3D printing device that uses short fibers to achieve the Z-axis crosslinking effect. Background Technology

[0002] Fiber-reinforced resin matrix composites are made of chopped or continuous fibers and their fabrics combined with thermosetting or thermoplastic resin matrices. They have advantages such as high specific modulus, high specific strength, good fatigue resistance, corrosion resistance and designability, and have been widely used in various fields such as aerospace, automobile manufacturing, and bridge construction.

[0003] The interlaminar failure strength (including interlaminar tensile strength, interlaminar shear strength and interlaminar fracture toughness) of composite materials is relatively weaker than that of in-plane failure. Interlaminar failure often occurs during use, leading to premature failure of the overall structure. In particular, the low interlaminar shear strength is an issue that must be considered in the design.

[0004] According to the literature (Chen Wenna. Factors Affecting the Performance of Short-Cut Carbon Fiber Reinforced Thermoplastic Composites [A]. Textile Science Research. 2021), in short-cut fiber reinforced thermoplastic composites, the length of the short fibers and the arrangement direction of the fibers in the resin matrix have a significant impact on the molded samples. Chinese patent (application number: 202010328297.X, entitled "A High-Performance Fiber Reinforced Thermoplastic Resin Matrix Composite Additive Manufacturing Method") uses a double-layer nozzle, with both the outer and inner layers activated simultaneously. The reinforcing short fibers are delivered through the outer nozzle and supplied with airflow, which is then heated by the inner nozzle. The block will become a high-temperature heat flow. At this time, due to the action of the high-temperature heat flow, the reinforcing short fibers will adhere to the resin composite material extruded from the inner nozzle, thereby improving the Z-direction bonding performance of the molded part. The disadvantage is that the short fibers are attached to the resin by the action of high-temperature airflow. During this process, the direction of the short fibers is difficult to control and the uniformity is difficult to guarantee, resulting in poor consistency and uniformity of the mechanical properties of the composite material. This chaotic arrangement of short fibers means that the short fibers cannot continuously transmit force, making the interlaminar strength enhancement of the composite material not obvious, and failing to give full play to the maximum advantage of short fiber reinforcement of the interlaminar strength of the composite material. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a composite material 3D printing device that uses short fibers to achieve the Z-axis crosslinking effect. During the printing process, a magnetic field is used to orient the short-cut fibers. By using a rotating magnetic field, the short-cut carbon fibers can be effectively controlled to be arranged in a spiral pattern in the resin, thereby improving the mechanical properties of the composite material reinforced by both long and short fibers.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A composite material 3D printing device for achieving Z-axis overseas Chinese association effect using short fibers includes a yarn spreading device, a microwave processing device 7, an external guide wheel 8, an ultrasonic device 9, a resin extruder 11, a magnetic field device 12, and a 3D printing device 13 arranged in sequence. The continuous fibers processed by the yarn spreading device enter the 3D printing device 13 in sequence through the microwave processing device 7, the external guide wheel 8, the resin extruder 11, and the magnetic field device 12.

[0008] The yarn spreading device consists of a material roll 1, a guide wheel 2, a rubber-coated wheel assembly 5, a fixed plate 6, an air-blowing clamp 4, and an air-blowing pipe 3. After the continuous fibers on the material roll 1 are initially guided by the guide wheel 2, they pass through the rubber-coated wheel assembly 5. The rubber-coated wheel assembly 5 and the air-blowing pipe 3 held by the air-blowing clamp 4 are mounted on the fixed plate 6. The air-blowing clamp 4 and the air-blowing pipe 3 are located above the rubber-coated wheel assembly 5. When the continuous fibers pass through the rubber-coated wheel assembly 5, the airflow at the air-blowing pipe 3 acts perpendicularly on the width direction of the continuous fiber bundle, thereby dispersing the continuous fiber bundle.

[0009] The microwave electric field emitted by the microwave processing device 7 acts perpendicularly to the length direction of the continuous fiber, thereby deepening the grooves on the surface of the continuous fiber.

[0010] The ultrasonic device 9 is connected to the fixed base plate of the external guide wheel 8. The ultrasonic transducer of the ultrasonic device 9 drives the external guide wheel 8 to vibrate at a high frequency. When the continuous fiber comes into contact with the resin in the molten pool of the resin extruder 11, this high-frequency vibration will cause more resin to enter the interior of the continuous fiber. Then, through the pressure of the outlet of the resin extruder 11, the interior of the continuous fiber is fully impregnated.

[0011] The resin extruder 11 has a feed port for chopped carbon fibers and resin powder at the right tail end and a screw in the middle section. The screw conveys the chopped carbon fibers and resin powder into the molten pool. After the resin powder enters the molten pool, it will become molten resin. At this time, the continuous fibers entering from the upper left will be wrapped together with the molten resin and chopped carbon fibers.

[0012] The magnetic field device 12 includes a hollow shaft 1207, with a magnet fixing device 1201 connected to the upper end of the hollow shaft 1207 and a magnet 1202 fixed on the magnet fixing device 1201; the lower end of the hollow shaft 1207 is fitted with a bearing 1209 and mounted on a bearing base 1210; the middle part of the hollow shaft 1207 is fitted with a driven bevel gear 1208, which meshes with a driving bevel gear 1206; the driving bevel gear 1206 is connected to the output shaft of a reducer 1204; the reducer 1204 is supported on a fixed bracket 1205; and the input shaft of the reducer 1204 is connected to a drive motor 1203.

[0013] The magnetic field device 12 is installed at the outlet of the resin extruder 11. When the magnet 1202 is energized, a magnetic field is formed. At this time, the orientation of the short carbon fiber 14 that has just been extruded from the outlet of the resin extruder 11 changes due to the magnetic field. Furthermore, the extrusion speed of the resin extruder 11 is adjusted by the sensor 10 to adapt to the rotation speed of the magnetic field, ensuring the uniformity of the spiral arrangement of the short carbon fiber in the resin.

[0014] The composite filaments are arranged in a spiral shape in the resin matrix by the rotational motion of the magnetic field device 12 and the extrusion motion of the resin extruder 11. Through these two motions, the orientation of the short-cut carbon fibers can be controlled.

[0015] After magnetic field treatment, the composite filament 14 is printed by the 3D printing device 13 to produce the designed sample. The central cylinder is abstracted as continuous fiber 1401, and the outer spiral is abstracted as spirally arranged short carbon fiber 1402. The fiber bundle with continuous fiber 1401 in the center and resin of short carbon fiber 1402 wrapped around continuous fiber 1401 is formed in the layers and between the layers as “short carbon fiber 1402 resin-continuous fiber 1401-short carbon fiber 1402 resin” structure. Then, it is gradually stacked from line to surface to volume, and finally the sample printing is completed.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) By designing an ultrasonic device installed on an external guide wheel, when the continuous fiber comes into contact with the resin in the melt pool, the vibration of the ultrasonic transducer allows more resin to enter the fiber, thus improving the wettability of the fiber.

[0018] (2) The orientation of short carbon fibers in resin is controllable. By designing a rotating magnetic field at the outlet of the resin extruder, the orientation of short carbon fibers can be controlled, thereby improving the interlayer performance of the composite material.

[0019] (3) The composite material 3D printing device based on magnetically oriented short fiber reinforced resin can realize the preparation and printing of prepreg bundles, and can obtain thermoplastic composite material reinforced by continuous fibers and short carbon fibers. The continuous fibers improve the strength, while the short carbon fibers enhance the interlayer strength. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention.

[0021] Figure 2 This is a schematic diagram of the rotating magnetic field structure of the present invention.

[0022] Figure 3 This is a printed image of the final specimen of the present invention.

[0023] Figure 4 This is a schematic diagram of a single filament bundle of resin reinforced with long and short fibers according to the present invention. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] like Figure 1 As shown, a composite material 3D printing device for achieving the Z-axis crosslinking effect using short fibers includes a yarn spreading device, a microwave processing device 7, an external guide wheel 8, an ultrasonic device 9, a resin extruder 11, a magnetic field device 12, and a 3D printing device 13 arranged sequentially. Continuous fibers processed by the yarn spreading device sequentially pass through the microwave processing device 7, the external guide wheel 8, the resin extruder 11, and the magnetic field device 12 before entering the 3D printing device 13. The yarn spreading device consists of a material roll 1, a guide wheel 2, a rubber-coated wheel assembly 5, a fixing plate 6, an air-blowing clamp 4, and an air-blowing pipe 3. The continuous fibers on the material roll 1 pass through the initial... After being guided, the continuous fiber passes through the V-shaped rubber-coated wheel assembly 5. The V-shaped rubber-coated wheel assembly 5 and the air blowing pipe 3 held by the air blowing clamp 4 are mounted on the fixed plate 6. The air blowing clamp 4 and the air blowing pipe 3 are located above the V-shaped rubber-coated wheel assembly 5. When the continuous fiber passes through the V-shaped rubber-coated wheel assembly 5, the airflow at the air blowing pipe 3 acts perpendicularly to the width direction of the continuous fiber bundle, thereby dispersing the continuous fiber bundle. During the yarn spreading process, the continuous fiber only comes into contact with the airflow and the rubber-coated wheel assembly 5, resulting in less damage to the continuous fiber. After passing through the yarn spreading, the continuous fiber bundle becomes thinner and is no longer wrapped by the sizing agent, thus improving the fiber wettability of the fiber-reinforced thermoplastic composite material.

[0026] After being unrolled, the continuous fibers are in a dispersed state. The microwave electric field emitted by the microwave processing device 7 acts perpendicularly to the length direction of the continuous fibers, which deepens the grooves on the surface of the continuous fibers, increases the surface roughness of the continuous fibers, increases the O / C atomic ratio on the surface of the processed continuous fibers, and increases the content of oxygen-containing functional groups, which is conducive to forming a good interface with the resin matrix.

[0027] The ultrasonic device 9 is connected to the fixed base plate of the external guide wheel 8. The vibration of the ultrasonic transducer of the ultrasonic device 9 will drive the external guide wheel 8 to vibrate together. When the continuous fiber passes through the external guide wheel 8, the continuous fiber will vibrate with this high-frequency vibration. When the continuous fiber comes into contact with the resin in the molten pool of the resin extruder 11, this high-frequency vibration will cause more resin to enter the interior of the continuous fiber. Then, through the pressure of the outlet of the resin extruder 11, the interior of the continuous fiber is fully impregnated, which reduces the voids and defects of the composite material sample and improves the molding quality.

[0028] The right tail of the resin extruder 11 is the feed port for chopped carbon fibers and resin powder. There is a screw in the middle section. The screw continuously transports the chopped carbon fibers and resin powder to the molten pool. After the resin powder enters the molten pool, it becomes molten resin. At this time, the continuous fibers entering from the upper left will be wrapped together with the molten resin and chopped carbon fibers. The orientation of the chopped carbon fibers is chaotic at this time.

[0029] like Figure 2 As shown, the magnetic field device 12 includes a hollow shaft 1207. The purpose of the hollow shaft 1207 is to allow the composite filament bundle to enter the 3D printing device 13 through the magnetic field device 12. A magnet fixing device 1201 is connected to the upper end of the hollow shaft 1207, and a magnet 1202 is fixed on the magnet fixing device 1201. The lower end of the hollow shaft 1207 is engaged with a bearing 1209 and installed on a bearing base 1210. The middle part of the hollow shaft 1207 is connected to a driven bevel gear 1208 through a key. The driven bevel gear 1208 meshes with a driving bevel gear 1206. The driving bevel gear 1206 is connected to the output shaft of the reducer 1204 through a key and is fixed by a fastening screw 1211 to prevent the gear from loosening during rotation and thus affecting the rotation of the magnetic field. The reducer 1204 is supported on a fixed bracket 1205, and the input shaft of the reducer 1204 is connected to a drive motor 1203.

[0030] The rotation of the magnetic field device 12 is achieved by the driven bevel gear 1208 and the driving bevel gear 1206. The rotation of the hollow shaft 1207 is driven by the gear transmission, which in turn drives the rotation of the upper magnet fixing device 1201. When the magnet 1202 is energized, a magnetic field is formed. At this time, the orientation of the short carbon fiber 14 that has just been extruded from the resin extruder 11 changes due to the magnetic field. Furthermore, the extrusion speed of the resin extruder 11 is adjusted by the sensor 10 to better adapt to the rotation speed of the magnetic field, thus ensuring the uniformity of the spiral arrangement of the short carbon fiber in the resin.

[0031] The magnetic field device 12 is installed at the outlet of the resin extruder 11. When the composite filament comes out of the outlet, it is still in a semi-molten state. When the magnetic force generated by the magnetic field device 12 is greater than the flow resistance of the chopped carbon fiber in the resin, the orientation of the chopped carbon fiber will change from random to N pole pointing to S pole under the action of the magnetic field. Since the external magnetic field is a rotating magnetic field, the N pole and S pole are also in a rotating state. Under the movement of the screw in the resin extruder 11, the composite filament is continuously extruded outward. Under the action of the two movements, including the rotational movement of the magnetic field device 12 and the extrusion movement of the resin extruder 11, the orientation of the chopped carbon fiber is arranged in a spiral shape in the resin matrix. Through the two movements, the orientation of the chopped carbon fiber is controlled.

[0032] like Figure 3As shown, the composite filament 14, after being treated with a magnetic field, enters the printer through the upper channel of the 3D printing device 13. After inputting the relevant printing program into the printer, the designed sample can be printed. Figure 3 The arrangement of the short-cut carbon fibers can be observed. For example... Figure 4 As shown, the central cylinder is abstracted as continuous fiber 1401, and the outer spiral is abstracted as spirally arranged short carbon fiber 1402. This achieves a fiber bundle with continuous fiber 1401 at the center and resin of short carbon fiber 1402 wrapped around continuous fiber 1401, forming a structure of "short carbon fiber 1402 resin - continuous fiber 1401 - short carbon fiber 1402 resin" within and between layers. Then, the structure is gradually accumulated from lines to surfaces to volumes, and finally, the sample printing is completed.

Claims

1. A composite material 3D printing device for achieving the Z-axis overseas Chinese association effect using short fibers, characterized in that: The device includes a yarn spreading device, a microwave processing device (7), an external guide wheel (8), an ultrasonic device (9), a resin extruder (11), a magnetic field device (12), and a 3D printing device (13) arranged in sequence. The continuous fibers processed by the yarn spreading device pass through the microwave processing device (7), the external guide wheel (8), the resin extruder (11), and the magnetic field device (12) in sequence before entering the 3D printing device (13). The yarn spreading device consists of a spool (1), a guide wheel (2), a rubber-coated wheel assembly (5), a fixed plate (6), an air-blowing clamp (4), and an air-blowing pipe (3). After the continuous fibers on the spool (1) are initially guided by the guide wheel (2), they pass through the rubber-coated wheel assembly (5). The rubber-coated wheel assembly (5) and the air-blowing pipe (3) held by the air-blowing clamp (4) are mounted on the fixed plate (6). The air-blowing clamp (4) and the air-blowing pipe (3) are located above the rubber-coated wheel assembly (5). When the continuous fibers pass through the rubber-coated wheel assembly (5), the airflow at the air-blowing pipe (3) acts perpendicularly to the width direction of the continuous fiber bundle, thereby dispersing the continuous fiber bundle. The magnetic field device (12) includes a hollow shaft (1207), with a magnet fixing device (1201) connected to the upper end of the hollow shaft (1207), and a magnet (1202) fixed on the magnet fixing device (1201); the lower end of the hollow shaft (1207) is fitted with a bearing (1209) and mounted on a bearing base (1210); the middle part of the hollow shaft (1207) is fitted with a driven bevel gear (1208), the driven bevel gear (1208) and the driving bevel gear (1206) mesh, the driving bevel gear (1206) is connected to the output shaft of a reducer (1204), the reducer (1204) is supported on a fixed bracket (1205), and the input shaft of the reducer (1204) is connected to a drive motor (1203); The magnetic field device (12) is installed at the outlet of the resin extruder (11). When the magnet (1202) is energized, a magnetic field is formed. At this time, the orientation of the short carbon fiber of the composite filament (14) that has just been extruded from the outlet of the resin extruder (11) changes due to the magnetic field. Furthermore, the extrusion speed of the resin extruder (11) is adjusted by the sensor (10) to adapt to the rotation speed of the magnetic field, thereby ensuring the uniformity of the spiral arrangement of the short carbon fiber in the resin. The composite filaments are arranged in a spiral shape in the resin matrix by the rotational motion of the magnetic field device (12) and the extrusion motion of the resin extruder (11). Through the two motions, the orientation of the short carbon fibers is controlled. The composite filament (14) after magnetic field treatment is printed by the 3D printing device (13) to produce the designed sample. The central cylinder is abstracted as continuous fiber (1401), and the outer spiral is abstracted as spirally arranged short carbon fiber (1402). The center is continuous fiber (1401), and the resin of short carbon fiber (1402) is wrapped around the fiber bundle outside the continuous fiber (1401). The structure of "short carbon fiber (1402) resin-continuous fiber (1401)-short carbon fiber (1402) resin" is formed in the layer and between the layers. Then, it is gradually accumulated from line to surface to volume, and finally the sample printing is completed.

2. The composite material 3D printing device for achieving the Z-axis overseas Chinese association effect using short fibers according to claim 1, characterized in that: The microwave electric field emitted by the microwave processing device (7) acts perpendicularly to the length direction of the continuous fiber, which deepens the grooves on the surface of the continuous fiber.

3. The composite material 3D printing device for achieving the Z-axis overseas Chinese association effect using short fibers according to claim 1, characterized in that: The ultrasonic device (9) is connected to the fixed base plate of the external guide wheel (8). The ultrasonic transducer of the ultrasonic device (9) drives the external guide wheel (8) to vibrate at high frequency. When the continuous fiber comes into contact with the resin in the melt pool of the resin extruder (11), this high-frequency vibration will cause more resin to enter the interior of the continuous fiber. Then, through the pressure of the outlet of the resin extruder (11), the interior of the continuous fiber is fully impregnated.

4. The composite material 3D printing device for achieving the Z-axis overseas Chinese association effect using short fibers according to claim 1, characterized in that: The right tail of the resin extruder (11) is the feed port for chopped carbon fibers and resin powder. There is a screw in the middle part. The screw transports the chopped carbon fibers and resin powder into the molten pool. After the resin powder enters the molten pool, it will become molten resin. At this time, the continuous fiber entering from the upper left will be wrapped together with the molten resin and chopped carbon fibers.

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