Ink direct writing additive manufacturing equipment based on fiber directional regulation and control and working method of ink direct writing additive manufacturing equipment

Abstract

The invention provides ink direct writing additive manufacturing equipment based on fiber directional regulation and control and a working method of the ink direct writing additive manufacturing equipment. The device comprises a fiber wire feeding system, a fiber / ceramic ink co-extrusion system and an ink direct-writing printing platform system, wherein the fiber wire feeding system and the fiber / ceramic ink co-extrusion system are arranged at the front part of the ink direct-writing printing platform system; the fiber wire feeding system comprises a servo motor, a gear, a roller, a bearing and a fiber transmission shaft; the fiber / ceramic ink co-extrusion system comprises a charging cylinder, a needle cylinder, a push rod, a Luer taper and a co-extrusion nozzle; the problems that in an existing ink direct writing technology, continuous fibers are prone to breakage depending on passive friction driving, and fibers are bent disorderly or locally gathered through a traditional single-channel nozzle are solved, the printing cost is effectively reduced, real-time synchronization of the fiber conveying speed and the ink extrusion speed is achieved, the possibility of fiber breakage is reduced, and the printing quality is improved. Fibers are physically isolated from ink, transverse deviation of the fibers is inhibited, and directional toughening of the fibers is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of additive manufacturing technology, in particular, especially relates to a fiber orientation control based ink direct writing additive manufacturing equipment and a working method thereof. BACKGROUND

[0002] With the rapid development of hypersonic vehicles, they face extreme aerodynamic heating environment (local temperature exceeding 2000℃) during service, which puts almost stringent requirements on the temperature resistance, thermal shock resistance and complex shaped structure forming ability of the hot end structural materials. Fiber reinforced ceramic matrix composites are considered as the ideal candidate materials for the next generation of ultra-high temperature structural parts due to their high temperature resistance and fiber toughening properties. For the extreme service environment of the aircraft under the new technology characteristics, the ceramic-based structural components with simple structure, fragmentation and low performance can no longer meet the requirements, and the advanced ceramic matrix composite manufacturing and structural design with complex structure, outstanding performance and structure-function integration characteristics become the key.

[0003] Therefore, the fiber reinforced ceramic forming technology based on additive manufacturing has become a research hotspot, which can directly realize the near-net forming of complex structures through layer-by-layer accumulation and is considered as the key technology to cause the revolution of advanced aerospace structures and materials. So far, although some three-dimensional printing technologies have been developed and applied in the field of advanced ceramic materials, compared with traditional processes, the existing three-dimensional printed ceramic materials generally face the problems of obvious brittleness and low damage tolerance. The direct ink writing (DIW) process uses ceramic ink with special rheological properties as raw material, and the ink is extruded through a nozzle moving along a predetermined path, so that the extruded ink is stacked layer by layer to obtain the target structure. This kind of printing process has the advantages of simple equipment, low cost and wide material applicability, and the fiber can be designed in the matrix, which has become one of the most promising ceramic matrix composite printing technologies.

[0004] Continuous fiber reinforced ceramic matrix composites are prepared by using DIW additive manufacturing technology, and fiber orientation control is the core key technology to break through the performance bottleneck of the material. The necessity of fiber orientation control is derived from the anisotropy of material performance and the requirement of extreme service environment. However, the existing equipment cannot meet the demand, and there are mainly the following difficulties: 1. At present, the fiber feeding mostly depends on the passive friction driving mechanism, and the extrusion speed of the fiber may lag behind the extrusion speed of the ink in the extrusion process. The fiber tension control is unstable due to pressure fluctuation or path bending, which causes fiber sticking and sliding, and even causes fiber fracture; 2. The fiber and ink are extruded together by using the traditional single-channel nozzle, and the fiber is easily deviated by Brownian motion under the high-pressure environment of ink extrusion, and the viscosity around the fiber changes suddenly due to the rheological property of ink shear thinning, so that the fiber is subjected to asymmetric drag force, forcing it to be disordered bending or locally gathered in the matrix. These problems seriously hinder the industrial application process of continuous fiber reinforced ceramic matrix composites. SUMMARY

[0005] In view of the problems in the prior art, the present application provides an ink direct writing additive manufacturing equipment based on fiber orientation control and a working method thereof. The present application mainly uses a new fiber feeding system to convert the passive friction driving fiber feeding into active delivery, realizes the real-time synchronization of the fiber delivery speed and the ink extrusion speed, reduces the possibility of fiber fracture, and designs a low-cost coaxial co-extrusion core-shell nozzle to physically isolate the fiber and the ink, maintain the stability of the ink flow field, inhibit the lateral deviation of the fiber, and realize the fiber directional reinforcement.

[0006] The technical means adopted by the present application are as follows: An ink direct writing additive manufacturing equipment based on fiber orientation control, characterized in that it comprises a fiber feeding system, a fiber / ceramic ink co-extrusion system and an ink direct writing printing platform system, wherein the fiber feeding system and the fiber / ceramic ink co-extrusion system are arranged at the front part of the ink direct writing printing platform system. The fiber feeding system comprises a servo motor, a gear, a roller, a bearing and a fiber transmission shaft, the output end of the servo motor is connected with the gear, the center of the gear is fixedly connected with the roller, the surface of the roller is made of elastic material, the roller is in contact with the surface of the bearing, a gapless fiber clamping pair is formed between the roller and the bearing, the fiber transmission shaft is arranged above the fiber clamping pair, and the fiber transmission shaft is fixed to the front part of the ink direct writing printing platform system. The fiber / ceramic ink co-extrusion system comprises a charging barrel, a needle cylinder, a push rod, a luer joint and a co-extrusion nozzle; the charging barrel and the push rod are fixed to the front part of the ink direct writing printing platform system, the needle cylinder is vertically assembled in the charging barrel, the lower part of the needle cylinder is connected with one end of the luer joint, the other end of the luer joint is connected with the side surface of the co-extrusion nozzle, the co-extrusion nozzle is arranged below the fiber clamping pair, and the push rod performs piston reciprocating motion in the needle cylinder.

[0007] Further, the output torque of the servo motor drives the gear to rotate, and the gear drives the roller and bearing to rotate synchronously. The continuous fiber at the end of the fiber transmission shaft is driven by the gravitational potential energy to enter the fiber clamping pair along a vertical trajectory. The fiber transmission shaft is passively rotated by the transmission of the continuous fiber.

[0008] Further, the co-extrusion nozzle adopts a coaxial double-channel conical structure design. The outer ink extrusion channel is arranged outside the inner fiber guide channel. The fiber guide channel has a conical angle of 2°, and the ink extrusion channel has a conical angle of 4°. The continuous fiber on the fiber transmission shaft enters the inner fiber guide channel, and the side end of the outer ink extrusion channel is connected with the luer joint.

[0009] Further, the diameter ratio of the inner fiber guide channel to the outer ink extrusion channel satisfies the following formula: , wherein, is the diameter of the fiber guide channel outlet, is the diameter of the ceramic ink extrusion channel outlet, is the push rod speed, is the layer thickness, is the co-extrusion nozzle moving speed.

[0010] Further, the ink direct writing printing platform system comprises a controller, a three-axis moving platform, a support, a printing platform, and a base. The controller, the support, and the printing platform are fixed on the base. The X-axis of the three-axis moving platform is fixed on the upper part of the support and is in sliding connection with the middle part of the Y-axis of the three-axis moving platform. The end of the Y-axis of the three-axis moving platform is in sliding connection with the Z-axis of the three-axis moving platform. The fiber feeding system and the fiber / ceramic ink co-extrusion system are arranged at the front part of the Z-axis of the three-axis moving platform.

[0011] Further, the X-axis, Y-axis, and Z-axis of the three-axis moving platform are ball screws. The maximum forming size of the printing platform is 300×200×200mm 3 .

[0012] Further, the controller is in electrical connection with the three-axis moving platform, the push rod, and the servo motor, forming an active servo tension closed-loop system. The fiber is monitored in real time by an optical fiber sensor, and the servo torque is dynamically adjusted by combining the PID algorithm.

[0013] Further, the continuous fiber on the fiber transmission shaft is a 1K carbon fiber bundle. The needle cylinder is internally provided with ceramic ink with a viscosity of 1×10 3 Pa·s-2.5×10 4 Pa·s.

[0014] The application also provides a working method of the ink direct writing additive manufacturing device based on fiber orientation control, which is realized based on any one of the ink direct writing additive manufacturing devices based on fiber orientation control. S1, vertically embedding the needle cylinder containing the ink into the inner cavity of the charging cylinder of the fiber / ceramic ink co-extrusion system, and then assembling the needle cylinder and the charging cylinder to the Z-axis of the three-axis moving platform; S2, connecting the needle cylinder and the outer ink extrusion channel inlet of the co-extrusion nozzle by using the luer joint, and then passing the continuous fiber at the end of the fiber feeding system into the inner fiber guide channel of the co-extrusion nozzle through the roller and the bearing; S3, the controller receives the control instruction and synchronously drives the three-axis moving platform to move according to the preset track of the control instruction; at the same time, the push rod pushes the needle cylinder to extrude the ink, the servo motor drives the roller and the bearing to convey the fiber through the gear, and the fiber and the ink pass through the tapered channel of the co-extrusion nozzle to be stacked and formed layer by layer on the printing platform.

[0015] Compared with the prior art, the application has the following advantages: The application provides an ink direct writing additive manufacturing device for ceramic matrix composite materials based on fiber orientation control, which realizes real-time synchronization of the fiber conveying speed and the ink extrusion speed by driving the fiber to be self-driven by the servo motor, reduces the possibility of fiber breakage, physically isolates the fiber guide channel and the ink extrusion channel by designing the co-extrusion nozzle, maintains the stability of the ink flow field, and realizes fiber orientation toughening at low cost by inhibiting the lateral deviation of the fiber. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0017] Figure 1 It is a schematic diagram of the overall structure of the device of the application.

[0018] Figure 2 It is a front view of the device of the application.

[0019] Figure 3 It is a side view of the device of the application.

[0020] Figure 4 It is an enlarged view of A in Figure 1

[0021] Figure 5 It is a schematic diagram of the co-extrusion nozzle of the application.​

[0022] Figure 6 Front view of the co-extrusion nozzle of the present application.

[0023] Figure 7 For Figure 6 B-B sectional view of the co-extrusion nozzle.

[0024] In the figure: 1, servo motor; 2, gear; 3, roller; 4, bearing; 5, fiber transmission shaft; 6, charging cylinder; 7, needle cylinder; 8, push rod; 9, Luer connector; 10, co-extrusion nozzle; 11, controller; 12, three-axis moving platform; 13, support; 14, printing platform; 15, base. DETAILED DESCRIPTION

[0025] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0027] It should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a feature, step, operation, device, component and / or combination thereof.

[0028] The foregoing is considered as illustrative only of the principles of the application. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the application to the exact construction and practice described. Accordingly, all such variations are intended to be included within the scope of the present application as defined in the following claims, along with full equivalents thereof.

[0029] In the description of the present application, it is to be understood that the orientation terms such as "front", "back", "up", "down", "left", "right", "transverse", "vertical", "horizontal", "top", "bottom", etc. indicate the orientation or positional relationship shown in the drawings, which are merely for the convenience of describing and simplifying the present application, and do not indicate or imply that the devices or elements referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the present application. The orientation terms "inner", "outer" refer to the inner and outer relative to the contour of the parts themselves.

[0030] For the convenience of description, spatial relative terms such as "over", "above", "upper surface", "upper", etc. can be used herein to describe the spatial positional relationship of one device or feature with respect to other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the devices described in the drawings. For example, if the devices in the drawings are inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" the other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0031] In addition, it should be noted that the use of the terms "first", "second", etc. to define parts only facilitates the distinction of the corresponding parts, and the above terms have no special meaning unless otherwise stated, and therefore cannot be understood as limiting the scope of protection of the present application.

[0032] As Figures 1-4As shown, the present application provides a kind of ceramic matrix composite ink direct writing additive manufacturing equipment based on fiber orientation regulation, including fiber feeding system, fiber / ceramic ink co-extrusion system and ink direct writing printing platform system, the fiber feeding system and fiber / ceramic ink co-extrusion system are set in the front of ink direct writing printing platform system; The fiber feeding system includes servo motor 1, gear 2, roller 3, bearing 4 and fiber transmission shaft 5, the output end of the servo motor 1 is connected with the gear 2, and the servo motor 1 and the gear 2 constitute a power input device, the center of the gear 2 is fixedly connected with the roller 3, the surface of the roller 3 is rubber material, the roller 3 is in contact with the surface of the bearing 4, and a fiber clamping pair without gap is formed between the roller 3 and the bearing 4, the elasticity of the rubber surface can make the fiber enter smoothly during fiber transmission, the fiber transmission shaft 5 is arranged above the fiber clamping pair, and the fiber transmission shaft 5 is connected to the ink direct writing printing platform system by bolts.

[0033] The elastic zero-gap fiber clamping pair can maximize the integrity of fiber morphology, if a gap type clamping structure is used, fiber-rotary shaft friction drive needs to be relied on, so that the fiber surface bears non-uniform shear stress, and fibrillation, hair dispersing and even fracture are induced, which seriously deteriorates the interface performance of the composite material.

[0034] The output torque of the servo motor drives the gear to rotate, and the gear drives the roller and the bearing to rotate synchronously, and the continuous fiber at the end of the fiber transmission shaft is guided into the fiber clamping pair along the vertical trajectory under the driving of gravitational potential energy, and the fiber transmission shaft is passively rotated by the transmission of the continuous fiber. This self-alignment mechanism significantly reduces the local shear stress on the fiber surface by eliminating lateral contact force, thereby inhibiting the fibrillation damage and loose hair structure induced by friction.

[0035] The fiber / ceramic ink co-extrusion system includes a charging barrel 6, a needle cylinder 7, a push rod 8, a luer connector 9 and a co-extrusion nozzle 10; the charging barrel 6 and the push rod 8 are fixed to the front of the ink direct writing printing platform system, the needle cylinder 7 is vertically assembled in the charging barrel 6, the lower part of the needle cylinder 7 is connected with one end of the luer connector 9, the other end of the luer connector 9 is connected with the side surface of the co-extrusion nozzle 10, the co-extrusion nozzle 10 is arranged below the fiber clamping pair, and the push rod 8 reciprocates in the needle cylinder 7. The co-extrusion nozzle 10 is threadedly connected to the end of the fiber feeding system, and the structure is as shown in Figures 5-7As shown, this is a dual-channel conical nozzle, comprising an inner fiber guiding channel (1mm outlet inner diameter) and an outer ink extrusion channel (2.2mm outlet inner diameter). The co-extrusion nozzle employs a coaxial dual-channel conical structure design, with the outer ink extrusion channel surrounding the inner fiber guiding channel. The fiber guiding channel has a cone angle of 2°, and the ink extrusion channel has a cone angle of 4°. This geometric configuration reduces friction on the fibers by decreasing the fiber-channel wall contact area and allows for precise control of fiber orientation. This reduces the unit manufacturing cost of the co-extrusion nozzle by 95%.

[0036] Determining the diameter ratio of the inner fiber guiding channel to the outer ink extrusion channel requires considering the effects of layer thickness, pusher speed, and co-extrusion nozzle movement speed. An empirical formula is obtained through experimental adjustments. , in, The diameter of the fiber guiding channel outlet. The diameter of the ceramic ink extrusion channel outlet. For push rod speed, For layer thickness, The optimal diameter ratio was calculated to be 0.45:1 based on the co-extrusion nozzle movement speed, resulting in the best printing effect.

[0037] The push rod 8 is subject to closed-loop adjustment in the ink direct-write printing platform system (embedded Hall sensor, which can monitor the push rod speed in real time; the controller can process the feedback signal and calculate the adjustment amount according to the formula as follows:)

[0038] in, For push rod speed, For rotational speed, The diameter of the ceramic ink extrusion channel outlet. To reduce system errors and ensure stable synchronous output of ink and fiber within the expected range, the outlet diameter of the fiber guiding channel is adjusted. This allows for precise piston reciprocating motion with a displacement stroke accuracy of ±10μm.

[0039] The ink direct-write printing platform system includes a controller 11, a three-axis moving platform 12, a bracket 13, a printing platform 14, and a base 15. The controller 11, the bracket 13, and the printing platform 14 are fixed to the base 15 by a high-rigidity mounting bracket with hexagonal bolts and locating pins. The three-axis moving platform 12 includes X, Y, and Z axes, with the X-axis fixed to the bracket 13. All three axes use ball screws to ensure low friction, high efficiency, and a repeatability accuracy of ≤±5μm. The maximum forming size of the printing platform 14 is 300×200×200mm. 3 ; The controller 11 is embedded with a professional 3D printing control card, which receives G code instructions related to motion control parameters, extrusion speed and pressure setting values, synchronously drives the three-axis moving platform 12 to complete XYZ three-axis linkage positioning, and controls the push rod 8 to work in coordination with the servo motor 1 to extrude the ceramic ink and continuous fibers to the forming area of the printing platform 14 according to the preset path.

[0040] The application also provides a working method of an ink direct writing additive manufacturing equipment based on fiber orientation regulation, which comprises the following steps: S1, vertically embedding the needle cylinder containing the ink into the inner cavity of the charging cylinder of the fiber / ceramic ink co-extrusion system, and then assembling the needle cylinder and the charging cylinder to the Z-axis of the three-axis moving platform; S2, connecting the needle cylinder and the outer ink extrusion channel entrance of the co-extrusion nozzle by using a luer joint, and feeding the continuous fibers at the end of the fiber feeding system into the inner fiber guide channel of the co-extrusion nozzle through the fiber transmission shaft between the rollers and the bearings, which can reduce the mechanical external force friction of the fibers in the transmission process compared with the fiber transmission by multiple friction wheels; S3, the controller receives the control instructions and synchronously drives the three-axis moving platform to move according to the preset trajectory of the control instructions; at the same time, the push rod pushes the needle cylinder to extrude the ink, the servo motor drives the rollers and bearings to convey the fibers through the gears, and the fibers and the ink are accumulated and formed layer by layer on the printing platform through the tapered channel of the co-extrusion nozzle.

[0041] Embodiment 1 A ceramic matrix composite ink direct writing additive manufacturing equipment based on fiber orientation regulation, which comprises a three-axis moving platform 12, a servo motor 1, a push rod 8, a co-extrusion nozzle 9 and a printing platform 14. Figures 1-7As shown, it comprises: servo motor 1, gear 2, roller 3, bearing 4, fiber transmission shaft 5, loading cylinder 6, needle cylinder 7, push rod 8, luer joint 9, co-extrusion nozzle 10, controller 11, three-axis moving platform 12, bracket 13, printing platform 14 and base 15. Among them, the output shaft of servo motor 1 is connected with precision gear 2 through a flat key, gear 2 is fixed at the center of driving roller 3, and driving roller 3 forms a fiber clamping pair with driven bearing 4. Fiber transmission shaft 5 is fixed on three-axis moving platform 12 through flange bolts, which ensures that the continuous fiber enters between roller 3 and bearing 4 in a vertical posture. Loading cylinder 6 and push rod 8 are installed on three-axis moving platform 12 through bolts, needle cylinder 7 is nested in the inner cavity of loading cylinder 6, co-extrusion nozzle 10 is connected with double-channel co-extrusion nozzle 10 through luer joint 9, co-extrusion nozzle 10 adopts coaxial nested design, the inner diameter of the outlet of the inner continuous fiber guide channel is 1.0mm, and the inner diameter of the outlet of the outer ceramic ink extrusion channel is 2.2mm (diameter ratio is 0.45:1); the tapered transition zone between the channels (fiber guide channel taper angle 2°, ink extrusion channel taper angle 4°) realizes fiber / ink flow field decoupling, ensures fiber orientation accuracy (orientation deviation <2°). Controller 11, bracket 13 and printing platform 14 are located below three-axis moving platform 12 and are fixed on base 15 (printing volume 300x200x200mm 3 ), the professional 3D printing control card in controller 11 analyzes G code instructions, synchronously drives three-axis moving platform 12 (positioning accuracy ±5μm), push rod 8 (positioning accuracy ±10μm) and servo motor 1, and realizes fiber / ink co-extrusion.

[0042] Example 2 The printing process of the fiber orientation control based ceramic matrix composite ink direct writing additive manufacturing equipment of example 1 comprises the following steps: S1, vertically embed the needle cylinder 7 filled with ink (viscosity is 1x10 3 Pa·s-2.5x10 4 Pa·s, measured at 25℃) into the inner cavity of the fiber / ceramic ink co-extrusion system loading cylinder 6, and then assemble them on the Z axis of the three-axis moving platform 12; S2, connect the ink channel inlet of the needle cylinder 7 and the co-extrusion nozzle 10 through the luer joint 9, and pass the fiber at the end of the fiber feeding system into the fiber guide channel in the inner layer of the co-extrusion nozzle 10, which can reduce the mechanical external force friction of the fiber in the transmission process compared with the multiple friction wheels conveying fiber; S3, import the G code generated by the path optimization algorithm, and controller 11 synchronously drives three-axis moving platform 12 to move according to the preset trajectory (repeated positioning accuracy ±5μm), push rod 8 pushes the needle cylinder 7 to extrude the ink, servo motor 1 drives roller 3 and bearing 4 to convey the fiber through gear 2, and the fiber and the ink pass through the tapered channel of co-extrusion nozzle 10 and are stacked on printing platform 14 layer by layer.

[0043] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An ink direct writing additive manufacturing apparatus based on fiber orientation regulation, characterized by, The fiber feeding system, the fiber / ceramic ink co-extrusion system and the ink direct writing printing platform system are arranged in the front part of the ink direct writing printing platform system. The fiber feeding system comprises a servo motor, a gear, a roller, a bearing and a fiber transmission shaft, the output end of the servo motor is connected with the gear, the center of the gear is fixedly connected with the roller, the surface of the roller is made of elastic material, the roller is in contact with the surface of the bearing, a fiber clamping pair without gap is formed between the roller and the bearing, the fiber transmission shaft is arranged above the fiber clamping pair, and the fiber transmission shaft is fixed to the front part of the ink direct writing printing platform system. The fiber / ceramic ink co-extrusion system comprises a charging barrel, a needle cylinder, a push rod, a luer joint and a co-extrusion nozzle, the charging barrel and the push rod are fixed to the front part of the ink direct writing printing platform system, the needle cylinder is vertically arranged in the charging barrel, the lower part of the needle cylinder is connected with one end of the luer joint, the other end of the luer joint is connected with the side surface of the co-extrusion nozzle, the co-extrusion nozzle is arranged below the fiber clamping pair, and the push rod performs piston reciprocating motion in the needle cylinder.

2. Ink direct-write additive manufacturing apparatus based on fiber orientation control according to claim 1, characterized in that, The output torque of the servo motor drives the gear to rotate, the gear drives the roller and the bearing to rotate synchronously, the continuous fiber at the end of the fiber transmission shaft is driven by gravitational potential energy and is guided into the fiber clamping pair along a vertical track, and the fiber transmission shaft is passively rotated by the transmission of the continuous fiber.

3. The ink direct-write additive manufacturing apparatus based on fiber orientation regulation of claim 1, wherein, The co-extrusion nozzle adopts coaxial double-channel conical structure design, the outer ink extrusion channel is arranged outside the inner fiber guide channel, the fiber guide channel has a conical angle of 2°, the ink extrusion channel has a conical angle of 4°, the continuous fiber on the fiber transmission shaft enters the inner fiber guide channel, and the side end of the outer ink extrusion channel is connected with the luer joint.

4. The ink direct-write additive manufacturing apparatus based on fiber orientation control of claim 3, wherein, The diameter ratio of the inner fiber guide channel to the outer ink extrusion channel satisfies the following formula. ， wherein, is the fiber guide channel exit diameter, is the ceramic ink extrusion channel exit diameter, is the push rod speed, is the layer thickness, is the co-extrusion nozzle movement speed.

5. The ink direct-write additive manufacturing apparatus based on fiber orientation control of claim 1, wherein, The ink direct writing printing platform system comprises a controller, a three-axis moving platform, a support, a printing platform and a base, the controller, the support and the printing platform are fixed to the base, the X-axis of the three-axis moving platform is fixed to the upper part of the support and is in sliding connection with the middle part of the Y-axis of the three-axis moving platform, the end of the Y-axis of the three-axis moving platform is in sliding connection with the Z-axis of the three-axis moving platform, and the fiber feeding system and the fiber / ceramic ink co-extrusion system are arranged in the front part of the Z-axis of the three-axis moving platform.

6. Ink direct-write additive manufacturing apparatus based on fiber orientation control according to claim 5, characterized in that, The X axis, Y axis and Z axis of the three-axis moving platform are ball screws, and the maximum forming size of the printing platform is 300*200*200mm 3 .

7. The ink direct-write additive manufacturing apparatus based on fiber orientation control of claim 5, wherein, The controller is electrically connected with the three-axis moving platform, the push rod, the servo motor and the sensor, thereby forming an active servo tension closed loop system, the fiber is monitored in real time through the optical fiber sensor, and the servo torque is dynamically adjusted in combination with a PID algorithm.

8. The ink direct-write additive manufacturing apparatus based on fiber orientation control of claim 1, wherein, The continuous fibers on the fiber drive shaft are 1K carbon fiber bundles, and the inside of the needle cylinder is provided with ceramic ink with a viscosity of 1×10 3 Pa·s-2.5×10 4 Pa·s.

9. A method of operation of a fiber orientation controlled ink direct-write additive manufacturing apparatus, implemented based on the fiber orientation controlled ink direct-write additive manufacturing apparatus of any one of claims 1-8, the method comprising: depositing a first layer of a first material on a substrate; depositing a second layer of a second material on the first layer; and depositing a third layer of a third material on the second layer, the third material having a different fiber orientation than the second material. The method comprises the following steps: S1, vertically embedding the needle cylinder filled with ink into the inner cavity of the charging barrel of the fiber / ceramic ink co-extrusion system, and then assembling the needle cylinder and the charging barrel on the Z-axis of the three-axis moving platform; S2, connecting the needle cylinder with the entrance of the outer ink extrusion channel of the co-extrusion nozzle through the luer joint, and guiding the continuous fiber at the end of the fiber feeding system into the inner fiber guide channel of the co-extrusion nozzle through the roller and the bearing; S3, the controller receives control instructions and synchronously drives the three-axis moving platform to move according to the preset trajectory of the control instructions; at the same time, the push rod pushes the needle cylinder to extrude ink, the servo motor drives the roller and bearing to convey the fiber through the gear, and the fiber and the ink pass through the conical channel of the co-extrusion nozzle and are stacked layer by layer on the printing platform to form a three-dimensional object.

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