Multi-tow continuous fiber reinforced concrete 3D printing device and method based on active yarn feeding

Abstract

The present invention provides a multi-tow continuous fiber reinforced concrete 3D printing device and printing method based on active yarn feeding. The active yarn feeding mechanism arranged on the periphery of the concrete barrel includes a drive system, a universal transmission assembly, a material roller shaft, and a yarn threading tube. The fiber tow drawn from the material roller passes through the yarn threading tube and extends into the inner cavity of the concrete barrel, and the fiber tow segment between the yarn threading tube outlet and the material roller is always in a relaxed state; the printing method steps include: pulling the fiber tow from the material roller and passing it through the yarn threading tube until the front end of the fiber tow extends into the inner cavity of the concrete barrel and is pulled out; turning on the active yarn feeding mechanism, and then turning on the concrete pumping system and power system. The concrete material enters the inner cavity of the concrete barrel and is stirred. The present invention is conducive to the stable deposition of continuous fiber tows inside the concrete module, fundamentally avoiding the problem of pulling the fiber tows out of the concrete module, and will not cause wear to the continuous fiber tows.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete 3D printing, and in particular to a multi-tow continuous fiber reinforced concrete 3D printing device and a printing method based on active yarn feeding. Background Art

[0002] 3D printing is primarily used in five sectors: transportation, aerospace, industrial equipment, consumer electronics, and healthcare. In recent years, with the increasing challenges of high resource consumption, high risk, and low production efficiency in traditional construction, concrete 3D printing technology has emerged, adhering to the principles of environmental protection, civilized construction, and low labor intensity. Concrete 3D printing technology uses a special "ink" made primarily of cementitious materials, admixtures, additives, specialty fibers, and aggregates. After converting architectural models into three-dimensional designs using computer graphics, the building is then printed and constructed through a layered, additive-based process.

[0003] Continuous fiber-reinforced concrete 3D printing is a new type of concrete 3D printing technology. It improves the mechanical properties and durability of concrete by adding continuous fiber reinforcement to traditional concrete 3D printing. This technology can produce stronger and more durable concrete components and has broad application prospects. A commonly used continuous fiber-reinforced concrete 3D printing (printing head) device primarily consists of a concrete barrel with a mixing assembly inside, connected to a power system. A printing nozzle is located at the bottom of the barrel for discharging the material. A continuous fiber supply mechanism is located on the side of the barrel. Fiber tows are drawn out and then extended into the barrel through holes in the barrel's sidewall. During printing, the fiber tows are continuously drawn out / pulled out primarily by friction between the concrete material and the fiber tows. However, this commonly used device still faces numerous challenges that need to be addressed and optimized. These include: Existing continuous fiber-reinforced concrete printing devices lack compatibility with silos of varying shapes and sizes; During printing, the fiber tows are subjected to high tension (typically 3-5N), hindering smooth deposition within the concrete mold and easily being pulled out of the mold (defined as the printed / deposited, uncured concrete material); Severe wear and tear on the fiber tows during printing, hindering the full performance of the fibers; and Proper uniform distribution of the fiber tows within the concrete mortar. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-tow continuous fiber reinforced concrete 3D printing device and printing method based on active yarn feeding, which can at least solve the technical problems mentioned in the background technology.

[0005] The present invention adopts the following technical solutions to solve the above technical problems.

[0006] A multi-tow continuous fiber reinforced concrete 3D printing device based on active yarn feeding includes a concrete barrel, a stirring assembly is arranged in the concrete barrel, the stirring assembly is connected to a power system, and an active yarn feeding mechanism is arranged on the periphery of the concrete barrel, the active yarn feeding mechanism includes a drive system, the output end of the drive system is connected to a universal transmission assembly, the universal transmission assembly is fixedly connected to a material roller shaft, a material roller with fiber material is arranged on the material roller shaft (the fiber bundle is wound on the material roller), and a yarn threading tube is arranged on the concrete barrel; wherein, the yarn threading tube inlet is located on the concrete barrel wall or outside the concrete barrel, and the yarn threading tube outlet is located at the lower part of the concrete barrel inner cavity and arranged downward; during the operation of the active yarn feeding mechanism, the fiber bundle drawn from the material roller passes through the yarn threading tube and extends into the concrete barrel inner cavity, and the fiber bundle segment between the yarn threading tube outlet and the material roller is always in a relaxed state.

[0007] In order to deposit the fiber bundles in the concrete module more flexibly and smoothly, multiple universal transmission assemblies are arranged around the concrete barrel. The upper end of each universal transmission assembly is connected to a pinion, and all the pinions are engaged with the same central gear. The central gear is rotatably connected to the lower cover of the concrete barrel through a central bearing; one of the pinions serves as a driving wheel and is connected to a motor. When the motor is running, it drives the driving wheel to rotate, and then drives the central gear and the remaining pinions to rotate.

[0008] In order to flexibly achieve uniform distribution of fiber bundles in concrete mortar, the corners and vertical sections of all yarn threading tubes are enclosed to form a cylindrical space. The cylindrical space can allow the inner layer of concrete material to flow, and the gaps between all adjacent yarn threading tubes can allow the outer layer of concrete material to flow.

[0009] In order to deposit the fiber bundles in the concrete module more flexibly and smoothly, the threading tube has an expansion section, and the large-diameter end of the expansion section is connected to the concrete barrel.

[0010] As a preferred solution, the expansion section is arranged horizontally or obliquely upward, and the axis of the material roller is perpendicular to the axis of the expansion section.

[0011] As a preferred solution, the universal transmission assembly adopts a telescopic double cross universal coupling, and the lower end of the material roller shaft is connected to the concrete barrel through a universal joint, a hinge or a connecting rod.

[0012] As a preferred solution, the concrete barrel is a conical barrel, or the upper part of the concrete barrel is cylindrical and the lower part is conical.

[0013] As a preferred solution, the concrete barrel is a conical barrel, and the outer edges of the stirring blades of the stirring assembly are located on the arc surface of the same cone.

[0014] A printing method using the aforementioned multi-tow continuous fiber reinforced concrete 3D printing device, comprising the following steps:

[0015] Step 1: Install the connecting plate of the printing device on the actuator of the 3D printing device;

[0016] Step 2: Pull the fiber tow from the material roller and pass it through the yarn threading tube until the front end of the fiber tow extends into the inner cavity of the concrete barrel, and then pull it out from the outlet of the printing nozzle;

[0017] Step 3: Connect the material pipe of the concrete pumping system to the feed pipe of the concrete barrel;

[0018] Step 4: First, the active yarn feeding mechanism is turned on to rotate the material roller shaft at a preset speed; then, the concrete pumping system and the power system are turned on to stir the concrete material after entering the concrete barrel cavity; wherein, the preset speed satisfies the requirement that "the fiber tow segment between the yarn threading tube outlet and the material roller is always in a relaxed state";

[0019] Step 5: Control the actuator to drive the printing device to print along a predetermined trajectory.

[0020] As a preferred solution, the yarn feeding speed is 1.2-1.5 times the discharge speed of the printing nozzle, and the active yarn feeding mechanism is controlled to operate in the manner of "running set time T1 - pause set time T2".

[0021] Beneficial effects: The solution of the present invention can not only maintain zero tension of the fiber bundle during the printing process (the tension value is not higher than 0.1N), which is beneficial to the stable deposition of the continuous fiber bundle inside the concrete module, fundamentally avoiding the problem of pulling the fiber bundle out of the concrete module, but also can always ensure that the friction of the continuous fiber bundle in the yarn guide path is very small, and the continuous fiber bundle can be directly transported from the starting point of the material roller to the end point of the concrete blending without any redundant yarn guide components in the middle, and will not cause wear to the continuous fiber bundle; the multi-tow continuous fiber reinforced concrete 3D printing device in the present invention is easy to install and disassemble, and is quick and easy to clean and maintain, and can be equipped with silos of different shapes and sizes, and has good compatibility; the solution of the present invention can make the fiber bundle evenly distributed in the concrete mortar, and can also accurately and flexibly adjust the distribution of the fiber bundles deposited inside the concrete module. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the multi-tow continuous fiber reinforced concrete 3D printing device based on active yarn feeding in Example 1;

[0023] Figure 2 2 is a schematic cross-sectional view of the multi-tow continuous fiber reinforced concrete 3D printing device based on active yarn feeding in Example 1;

[0024] Figure 3 3D printing apparatus for multi-tow continuous fiber reinforced concrete based on active yarn feeding in Example 1 is a schematic diagram of a disassembled state;

[0025] Figure 4 This is a schematic diagram of the external structure of the material roller shaft in Example 1;

[0026] Figure 5 1 is a schematic cross-sectional view of the material roller shaft in Example 1;

[0027] Figure 6 Schematic diagram of the yarn feeding tube and the yarn threading tube at the lower part of the concrete barrel in Example 1;

[0028] Figure 7 This is a three-dimensional schematic diagram of the concrete barrel in Example 1;

[0029] Figure 8 This is a three-dimensional schematic diagram of the material roller shaft in Example 2;

[0030] Figure 9 This is a schematic diagram of the material roller shaft in Example 2;

[0031] Figure 10 2 is a schematic cross-sectional view of the material roller shaft in Example 2;

[0032] Figure 11 Schematic diagram of the multi-tow continuous fiber reinforced concrete 3D printing device based on active yarn feeding in Example 4. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following embodiments are only intended to help understand the principles and core concepts of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements made to the present invention without departing from the principles of the present invention also fall within the scope of protection of the claims of the present invention. Example 1

[0034] like Figures 1 to 7As shown, a multi-tow continuous fiber reinforced concrete 3D printing device based on active yarn feeding includes a concrete barrel 4, a feed pipe 5 is provided on the concrete barrel 4, a stirring assembly is provided inside the concrete barrel 4, the stirring assembly is connected to a power system 6, an active yarn feeding mechanism is provided on the periphery of the concrete barrel 4, the active yarn feeding mechanism includes a drive system 7, an output end of the drive system 7 is connected to a universal transmission assembly 71, the universal transmission assembly 71 is fixedly connected to a material roller shaft 32, a material roller 33 with fiber material is provided on the material roller shaft 32, and a yarn threading tube 35 is provided on the concrete barrel 4; The yarn feeding tube 35 comprises a horizontal section and a vertical section. The horizontal section is fixedly connected to a hole in the sidewall of the yarn feed tube 41 at the bottom of the concrete barrel 4. The inlet of the yarn feeding tube 35 (the outer end of the horizontal section) is located on the wall of the concrete barrel 4 or outside the concrete barrel 4, and the outlet of the yarn feeding tube 35 (the lower end of the vertical section) is located at the lower part of the concrete barrel 4 and faces downward. During operation of the active yarn feeding mechanism, the fiber bundle 37 drawn from the material roller 33 passes through the yarn feeding tube 35 and extends into the concrete barrel 4. The fiber bundle segment between the outlet of the yarn feeding tube 35 and the material roller 33 remains relaxed. The corners of all the yarn feeding tubes 35 and the vertical sections 352 together enclose a cylindrical space 51. The cylindrical space 51 can flow through the inner layer of concrete material, and the gaps 52 between all adjacent yarn feeding tubes 35 can flow through the outer layer of concrete material.

[0035] In this embodiment, the concrete barrel 4 is a conical barrel. A circular lower cover 72 is provided at the top of the concrete barrel 4. An upper cover 75 is fitted on the lower cover 72, and a connecting plate 8 is provided on the upper cover 75. A coaxial through-hole is provided in the middle of the upper and lower covers 75 and 72. This through-hole is primarily for passing the stirring shaft 66 of the stirring assembly. A retaining ring 68 is provided on the lower cover 72 and positioned coaxially with the through-hole. The outer edge of the stirring blade 67 of the stirring assembly is close to the inner wall of the concrete barrel 4, that is, the outer edge of the stirring blade 67 is located on the same arc surface of the cone.

[0036] In this embodiment, the power system 6 specifically includes a servo motor 62, a right-angle reducer 61, and a reducer coupling 63 connected in sequence. The lower end of the reducer coupling 63 is connected to the stirring shaft 66. The stirring shaft 66 is provided with a roller bearing 65 installed in the through hole in the middle of the lower cover 72. The right-angle reducer 61 is installed on the support frame 64, and the support frame 64 is installed on the upper cover 75.

[0037] In this embodiment, the drive system 7 includes a motor 74 (a servo motor) mounted on the upper cover 75 through a motor base 76. The output end of the motor 74 is connected to a coupling 73. The coupling 73 is also connected to a pinion shaft 713. A sleeve 712 is provided on the pinion shaft 713. The bearing provided on the sleeve 712 is connected to the lower cover 72. A pinion 710 is provided on the pinion shaft 713. The pinion 710 serves as a driving wheel. The lower end of the pinion shaft 713 is connected to one of the universal transmission assemblies 71. A plurality of universal transmission assemblies 71 are arranged (evenly arranged) around the concrete barrel 4. Each universal transmission assembly 71 The upper end of the pinion 710 is connected to the upper end of the pinion 710. Except for the pinion 710 that serves as the driving wheel, the upper end of each pinion 710 is provided with a limit member 79 for fixing the pinion 710. All the pinion gears 710 are engaged with the same central gear 78. The central gear 78 is rotatably connected to the lower cover 72 of the concrete barrel 4 through a central bearing 77. The central bearing 77 is mounted on the retaining ring 68. When the motor 74 is running, it drives the driving wheel to rotate, thereby driving the central gear 78 to rotate. The rotation of the central gear 78 drives the other pinion gears to rotate. When all the pinion gears 710 rotate, they drive all the universal transmission components 71 to rotate, thereby driving the material roller shaft 32 to rotate.

[0038] In this embodiment, the universal transmission assembly 71 utilizes a retractable double cross universal joint. The lower end of the material roller shaft 32 is mounted on a connecting rod 39 via a bearing 36. The connecting rod 39 is horizontally connected to the concrete drum 4. The material roller shaft 32 is perpendicular to the connecting rod, and a material roll 34 formed of fiber tow is wound around the material roller shaft 32. The connecting rod 39 is a telescopic rod. In one product solution, the double cross universal joint comprises a telescopic rod and two cross universal joints connected at each end of the telescopic rod. The telescopic rod comprises an outer tube and an inner rod. The upper end of the inner rod is connected to one of the cross universal joints, which is inserted into the outer tube. The lower end of the outer tube is connected to the other cross universal joint. Once the inner rod is adjusted to the desired length relative to the outer tube, it can be secured with a pin. When the cross universal joint at the upper end of the inner rod and the inner rod rotate under the drive of the motor 74, the outer tube and the other cross universal joint rotate synchronously with the inner rod. In this embodiment, the lower end of the concrete barrel 4 is connected to the upper end of the yarn feed tube 41 via a flange structure. In other embodiments, the yarn feed tube 41 can also be integrally formed with the concrete barrel 4. In this embodiment, the yarn feed tube 41 is threadedly connected to the printing nozzle 1, and the radial cross-section of the printing nozzle 1 is rectangular.

[0039] A printing method using the multi-tow continuous fiber reinforced concrete 3D printing device of this embodiment comprises the following steps:

[0040] Step 1: Install the connecting plate 8 of the printing device on the actuator of the 3D printing device;

[0041] Step 2: Pull the fiber tow 37 from the material roller 33 and pass it through the yarn threading tube 35 until the front end of the fiber tow 37 extends into the inner cavity of the concrete barrel 4 and then is pulled out from the outlet of the printing nozzle 1;

[0042] Step 3: Connect the material pipe of the concrete pumping system to the feed pipe 5 of the concrete barrel 4;

[0043] Step 4: First, the active yarn feeding mechanism is turned on to rotate the material roller shaft 32 at a preset speed; then, the concrete pumping system and the power system 6 are turned on, and the concrete material enters the inner cavity of the concrete barrel 4 and is stirred; wherein, the preset speed satisfies the requirement that "the fiber tow segment between the outlet of the yarn threading tube 35 and the material roller 33 is always in a relaxed state";

[0044] Among them, when the rotation speed of the stirring shaft 66 is constant, the yarn feeding speed is 1.2-1.5 times the discharge speed of the printing nozzle 1, and the active yarn feeding mechanism is controlled to operate in the manner of "running set time T1-pausing set time T2", for example, after the motor 74 of the active yarn feeding mechanism runs for 20 seconds, the motor 74 is controlled to pause for 5 seconds, and then the motor 74 is controlled to run for 20 seconds and then pause for 5 seconds, and so on;

[0045] In specific implementation, a PLC controller is used to control the operation of the motor 74, so that the material roller shaft 32 rotates at a preset speed, thereby controlling the discharge speed of the fiber tow (i.e., the yarn feeding speed); the PLC controller controls the operation of the servo motor 62, so that the stirring shaft 66 rotates at a set speed, thereby controlling the extrusion flow rate of the concrete;

[0046] Step 5: Control the actuator to drive the printing device to print along a predetermined trajectory. Example 2

[0047] A multi-tow continuous fiber reinforced concrete 3D printing device based on active yarn feeding, the main structure of which refers to Example 1, and the main difference between it and Example 1 is that: Figures 8 to 10 As shown, the yarn threading tube 35 has an expansion section 351, the large diameter end of the expansion section 351 is connected to the hole on the side wall of the yarn feeding tube 41 at the lower part of the concrete barrel 4, the expansion section 351 is arranged horizontally or obliquely upward, and the axis of the material roller 33 is perpendicular to the axis of the expansion section 351; wherein, combined with Figure 10 As shown, the inner side of the upper extension line of the inner wall of the expansion section 351 is always higher than the straightened fiber bundle 37, and the inner side of the lower extension line of the inner wall of the expansion section 351 is always lower than the straightened fiber bundle 37. Example 3

[0048] A multi-tow continuous fiber reinforced concrete 3D printing device based on active yarn feeding, the main structure of which refers to Example 1, and the main difference from Example 1 is that the lower end of the material roller shaft 32 is connected to the concrete barrel 4 through a universal joint or a hinge. Example 4

[0049] A multi-tow continuous fiber reinforced concrete 3D printing device based on active yarn feeding, the main structure of which refers to Example 1, and the main difference between it and Example 1 is that: Figure 11 As shown, the upper part (drawing number 44) of the concrete barrel 4 is cylindrical and the lower part (drawing number 45) is conical, and the radial cross-section of the printing nozzle 1 is circular. The nozzle type can also be flexibly selected according to actual needs.

[0050] The solution of the present invention can not only maintain zero tension of the fiber bundle during the printing process (the tension value is not higher than 0.1N), which is conducive to the stable deposition of the continuous fiber bundle inside the concrete module, fundamentally avoiding the problem of pulling the fiber bundle out of the concrete module, but also can always ensure that the friction of the continuous fiber bundle in the yarn guide path is very small. The continuous fiber bundle can be directly transported from the starting point of the material roller to the end point of the concrete blending without any redundant yarn guide components in the middle, and will not cause wear to the continuous fiber bundle; the multi-tow continuous fiber reinforced concrete 3D printing device in the present invention is easy to install and disassemble, and is quick and easy to clean and maintain, and can be equipped with silos of different shapes and sizes, and has good compatibility; the solution of the present invention can make the fiber bundle evenly distributed in the concrete mortar, and can also accurately and flexibly adjust the distribution of the fiber bundles deposited inside the concrete module.

[0051] In one application scenario, ten sets of universal drive assemblies 71 and ten sets of material rollers 33 are arranged (evenly spaced) around the concrete barrel 4. During the printing process, an appropriate number of fiber tows 37 can be selected based on the size of the concrete module to be printed. If ten fiber tows 37 are to be evenly spaced within the concrete module, an active yarn feeding mechanism can be used to control the operation of all material rollers 33 and actively feed yarn. If five fiber tows 37 are to be evenly spaced within the concrete module, material rolls 34 can be placed on five of the material rollers 33, and the active yarn feeding mechanism can be used to control the active yarn feeding of all five material rollers 33.

[0052] In the present invention, the universal drive assembly can deflect, achieving transmission between two non-colinear axes within a certain angle range (set to 0-40°). This allows compatibility with silos of varying shapes and sizes, avoiding unequal speeds between the input and output ends, and achieving uniform speed transmission between the two ends. In the present invention, all feed rollers can operate and adjust synchronously, ensuring that the discharge speed of each fiber bundle is completely consistent, primarily dependent on the concrete feed rate. During use, concrete raw materials are pumped into the concrete barrel, where they are squeezed into the yarn feed tube by the agitator shaft and then extruded through the print nozzle onto the printing platform. The active yarn feed mechanism drives the feed roller shaft to rotate, actively rotating it and achieving active yarn feed. After being drawn from the material roll, the continuous fiber bundle enters the yarn feed tube directly through the yarn threading elbow, where it is further blended with the concrete mortar before being extruded through the print nozzle onto the printing platform.

[0053] During the printing process, part of the concrete material is extruded vertically downward from the cylindrical space 51 in a columnar structure, and another part of the concrete material is extruded vertically downward from the gap 52 between adjacent yarn threading tubes 35 in a strip structure. The fiber bundle is located between these two parts of concrete material. These two parts of concrete material squeeze the fiber bundle toward each other in the printing nozzle 1, thereby positioning the fiber bundle in a specific area in the concrete, and then bringing the fiber bundle downward.

Claims

1. A multi-tow continuous fiber reinforced concrete 3D printing device based on active yarn feeding, comprising a concrete barrel (4), a stirring assembly provided in the concrete barrel (4), the stirring assembly being connected to a power system (6), characterized in that: An active yarn feeding mechanism is provided on the periphery of the concrete barrel (4), and the active yarn feeding mechanism includes a drive system (7), an output end of the drive system (7) is connected to a universal transmission assembly (71), the universal transmission assembly (71) is fixedly connected to a material roller shaft (32), a material roller (33) with fiber material is provided on the material roller shaft (32), and a yarn threading tube (35) is provided on the concrete barrel (4); wherein, the inlet of the yarn threading tube (35) is located on the wall of the concrete barrel (4) or outside the concrete barrel (4), and the outlet of the yarn threading tube (35) is located at the lower part of the inner cavity of the concrete barrel (4) and is arranged downward; during the operation of the active yarn feeding mechanism, the fiber bundle drawn from the material roller (33) passes through the yarn threading tube (35) and extends into the inner cavity of the concrete barrel (4), and the fiber bundle segment between the outlet of the yarn threading tube (35) and the material roller (33) is always in a relaxed state; a plurality of universal transmission assemblies (71) are arranged around the concrete barrel (4), and the upper end of each universal transmission assembly (71) is connected to a small gear (710), and all the small gears (710) are engaged with the same central gear (78), and the central gear (78) is rotatably connected to the lower disc cover (72) of the concrete barrel (4) through a central bearing (77); one of the small gears serves as a driving wheel and is connected to the motor (74), and when the motor (74) is running, it drives the driving wheel to rotate, thereby driving the central gear (78) and the remaining small gears to rotate.

2. The multi-tow continuous fiber reinforced concrete 3D printing device according to claim 1, characterized in that: The corner portions and vertical sections (352) of all threading tubes (35) together enclose a cylindrical space (51), and the cylindrical space (51) can allow the inner layer of concrete material to flow, and the gaps between all adjacent threading tubes (35) can allow the outer layer of concrete material to flow.

3. The multi-tow continuous fiber reinforced concrete 3D printing device according to claim 2, characterized in that: The threading tube (35) has an expansion section (351), and the large diameter end of the expansion section (351) is connected to the concrete barrel (4).

4. The multi-tow continuous fiber reinforced concrete 3D printing device according to claim 3, characterized in that: The expansion section (351) is arranged horizontally or obliquely upward, and the axis of the material roller (33) is perpendicular to the axis of the expansion section (351).

5. The multi-tow continuous fiber reinforced concrete 3D printing device according to claim 4, characterized in that: The universal transmission assembly (71) adopts a telescopic double cross universal coupling, and the lower end of the material roller shaft (32) is connected to the concrete barrel (4) through a universal joint, a hinge or a connecting rod.

6. The multi-tow continuous fiber reinforced concrete 3D printing device according to any one of claims 1 to 5, characterized in that: The concrete barrel (4) is a conical barrel, or the upper part of the concrete barrel (4) is cylindrical and the lower part is conical.

7. The multi-tow continuous fiber reinforced concrete 3D printing device according to any one of claims 1 to 5, characterized in that: The concrete barrel (4) is a conical barrel, and the outer edges of the stirring blades of the stirring assembly are located on the arc surface of the same cone.

8. A printing method using the multi-tow continuous fiber reinforced concrete 3D printing device according to any one of claims 1 to 7, characterized in that the steps include: Step 1, installing the connecting plate (8) of the printing device on the actuator of the 3D printing device; Step 2, pulling the fiber bundle from the material roller (33) and passing it through the yarn threading tube (35) until the front end of the fiber bundle extends into the inner cavity of the concrete barrel (4), and then pulling it out from the outlet of the printing nozzle (1); Step 3, connecting the material pipe of the concrete pumping system to the feed pipe (5) of the concrete barrel (4); Step 4, first start the active yarn feeding mechanism to rotate the material roller shaft (32) at a preset speed; then start the concrete pumping system and the power system (6), and the concrete material enters the inner cavity of the concrete barrel (4) and is stirred; wherein the preset speed satisfies the requirement that "the fiber tow segment between the outlet of the yarn threading tube (35) and the material roller (33) is always in a relaxed state"; Step 5: Control the actuator to drive the printing device to print along a predetermined trajectory.

9. The printing method according to claim 8, wherein: The yarn feeding speed is 1.2-1.5 times the discharge speed of the printing nozzle (1), and the active yarn feeding mechanism is controlled to operate in the manner of "running set time T1-pausing set time T2".

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