3D printing head with double-sided adjustable curved doctor blade, application method and control method

Abstract

This invention discloses a 3D printing head with adjustable curved surface scrapers on both sides, its application method, and its control method. The printing head includes a mounting base, a material guide tube, a rotating frame, left and right scraper units, a lifting mechanism, and a deformation mechanism. Each scraper unit includes a support frame, a lifting mechanism, a deformation mechanism, and a scraper assembly. The scraper assembly consists of multiple hinged scraper blades. The deformation mechanism controls the deflection of each scraper blade through a drive mechanism to form an adjustable curved working surface. The lifting mechanism drives the support frame to rise and fall independently, enabling adjustment of the scraper's working height and unilateral avoidance. The rotating frame can be driven by a rotation drive mechanism, ensuring that the scrapers always face both sides of the printing strip, i.e., the scraper's shaping direction is always perpendicular to the printing strip direction. The control method uses path planning, collision detection, and surface and drive quantity calculation to coordinate the actions of each mechanism. This invention achieves CNC shaping of the curved surfaces of the two sidewalls of the printing strip.

Description

Technical Field

[0001] This invention relates to the technical field of extrusion 3D printing of slurry materials, and specifically to a 3D printing head with a double-sided adjustable curved scraper and its control method. Background Technology

[0002] With the development of 3D printing technology in construction, the use of printing nozzles to extrude and stack cement-based materials, alkali-activated / geopolymer materials, and soil-based materials layer by layer along a preset path to form walls, panels, or irregularly shaped building components has become an important technical route in automated building construction. In this type of printing process, the surface smoothness, side regularity, and interlayer forming consistency of the newly extruded strip directly affect the appearance quality, dimensional accuracy, and deposition effect of subsequent layers of the component. Therefore, timely trimming / smoothing of the newly formed strip (especially the two sidewalls of the strip) after concrete extrusion has become an important technical direction in the design of 3D printing nozzles and printing equipment for construction.

[0003] To address the aforementioned needs, various architectural 3D printing nozzles and related devices with smoothing, leveling, or shaping functions have been proposed in the existing technology. For example, a 3D printing nozzle device for construction (CN201711071970.0) includes a smoothing mechanism that can be hung on the top; a concrete 3D printer nozzle (CN202110252483.4) includes an adjustable-width smoothing plate, which includes a first smoothing plate and a second smoothing plate; another architectural 3D printing nozzle device (CN201521132151.9) includes a liftable and rotatable smoothing component. These solutions demonstrate that numerous patents in the field have incorporated smoothing components at the printing nozzle to surface-finish new printed strips, thereby improving the forming quality of concrete 3D printed strips.

[0004] Among the aforementioned prior art, the closest solution to this invention is represented by the technical route described in application number US20180345533A1. This type of solution typically includes: an annular connecting base rotatable around the printhead axis; a fixed back plate extending vertically from this base; and multiple linear actuators mounted on the back plate, each controlling a smoothing surface. By adjusting the extension and retraction of each linear actuator, the enclosure angle or curvature of each smoothing surface can be changed. Its characteristic is that the entire adjustable smoothing mechanism can rotate 360 ​​degrees around the printhead. However, this solution also has significant drawbacks: the overall structure is relatively complex, and the entire end smoothing mechanism connected to the fixed back plate cannot extend or retract, leading to easy interference with the printing substrate when printing the first layer of material strips. Furthermore, its multiple linear actuators and associated fixed back plates are all arranged behind the smoothing surface, resulting in a large overall volume, which easily leads to interference with the already printed material strips during operation.

[0005] Furthermore, solutions such as (US5529471A) also embody the technical approach of incorporating shaping or surface treatment mechanisms into additive manufacturing equipment to improve the quality of deposition molding. This demonstrates that existing technology has gradually evolved from simply shaping the extruded strip to tailoring the printed surface, especially complex or curved surfaces. Some solutions also attempt to combine structural designs such as movable connections, attitude adjustment, or adaptive surface trimming to enhance surface treatment capabilities during the printing process.

[0006] Based on the above-mentioned existing technology, the following main and secondary disadvantages can be summarized: 1. The most significant drawback Existing smoothing mechanisms struggle to balance lightweight design with adjustable curved surface deformation capabilities on both sides. Consequently, they cannot achieve stable and effective smoothing or trimming of the sides of newly printed concrete strips when both sides of the printed component are curved. This is because: firstly, rigid smoothing mechanisms cannot adapt to the curved surface shape, preventing the scraper from conforming to the required surface profile of the printed component; secondly, while some structures possess variable curved surface smoothing capabilities, their bulkiness, limited freedom of movement, or insufficient obstacle avoidance can easily lead to interference with already printed strips during the printing process. The direct result is that the printed surface still fails to achieve an ideal flatness, especially when printing curved surfaces, where surface quality issues are more pronounced, thus affecting the component's appearance, dimensional consistency, and the forming quality of subsequent layers.

[0007] 2. One of the minor drawbacks: The straight scraper cannot be deformed (patents with this drawback include: CN201711071970.0, CN202110252483.4, CN201521132151.9, and US5529471A). Most existing smoothing mechanisms consist of a straight scraper that cannot deform or has insufficient deformation capacity. Therefore, they are only suitable for flat or simple surfaces and cannot smooth curved surfaces. In other words, because the shape of the smoothing component is fixed, when the printing path is curved and the printing surface is curved, it is difficult to form a continuous and uniform contact between the scraper and the strip surface. This leads to problems such as incomplete smoothing in some areas, excessive smoothing in some areas, or discontinuous surface finishing.

[0008] 3. Secondary drawback: The scraper cannot be lifted from one side (patent with this drawback: CN201521132151.9) Some mechanisms with dual-sided scrapers cannot achieve single-sided lifting or single-sided avoidance, meaning they cannot independently control the lifting of either scraper. Therefore, during infill path printing (i.e., when two adjacent printed strips are close together or densely paved), if the smoothing mechanism's forward direction conflicts with the already printed strips, it cannot flexibly perform localized surface finishing. The causal relationship is as follows: because the mechanism cannot independently lift or avoid the scraper on one side according to the actual printing state, in complex paths, corner paths, or infill paths, the smoothing mechanism is prone to interfering with existing strips, thus affecting printing continuity and surface finishing effects.

[0009] 4. The third minor drawback: The variable scraper drive mechanism is huge and bulky (patent with this drawback: US20180345533A1). Some hydraulically driven deformable smoothing mechanisms are bulky and heavy, which can easily interfere with the already printed strips during the printing process. This structural bulk not only affects the installation and control of the mechanism, but also limits the flexibility of the print head in confined spaces or complex curved paths, thus hindering the improvement of printing accuracy and forming quality.

[0010] 5. Fourth minor drawback: It only has a single-sided scraper (patents with this drawback include: US20180345533A1, CN201610318731.X). Some existing smoothing mechanisms can only smooth one side when printing along a single straight line; if smoothing of the other side is required, printing must be stopped and the print head rotated (which simultaneously rotates the scraper to the other side). This results in a discontinuous printing process, complex operation, and reduced efficiency, especially in curved paths, multi-directional paths, or continuous track-changing printing, where these defects become more pronounced. Summary of the Invention

[0011] The purpose of this invention is to provide a 3D printing head with adjustable curved surface scrapers on both sides that can adapt to complex curved surfaces, achieve precise layering and smoothing, and effectively avoid collisions, as well as its application and control methods.

[0012] To achieve the above objectives, the present invention adopts the following technical solution: A 3D printing head with a dual-sided adjustable curved scraper includes a mounting base, a material guide tube, a rotating frame, a scraper unit, a lifting mechanism, and a deformation mechanism; The mounting base is used to connect to an external printing actuator; The material guide tube is disposed on the rotating frame, and a through channel is formed inside it for material to pass through, which is used to guide the raw material from the upper feeding system to the lower print head; The rotating frame is connected to the mounting base, and the mounting base is provided with a rotation drive mechanism that drives the rotating frame to rotate around its axis. The scraper unit consists of two sets, which are respectively arranged on both sides of the rotating frame; Each scraper unit includes a support frame, a lifting mechanism, a deformation mechanism, and a scraper assembly; The lifting mechanism is located on the side of the rotating frame, connected to the support frame, and drives the support frame to reciprocate in the vertical direction. The scraper assembly, which is mounted on the support frame, includes a plurality of scraper blades connected in series by hinges, and the scraper blades close to the support frame are hinged to the support frame. The deformation mechanism includes a driving component and a traction component; the driving component is mounted on the support frame; the traction component is used to connect the driving component to a corresponding scraper blade in the scraper assembly; The drive components of the rotary drive mechanism, lifting mechanism, and deformation mechanism are each independent drive sources; the drive component of the deformation mechanism controls the extension and retraction of the traction component, changing the deflection angle of the corresponding scraper blade, thereby enabling multiple scraper blades to form an adjustable curved scraper working surface.

[0013] Preferably, the support frame is a scraper bracket, and the scraper assembly includes at least three scraper blades connected in series by hinges, which are sequentially defined as the first scraper blade, the second scraper blade, ... the mth scraper blade from the direction away from the scraper bracket to the direction closer to the scraper bracket; The number of driving components of the deformation mechanism is the same as the number of scraper blades, and the driving component of each deformation mechanism is disposed on the scraper bracket; and the installation position of each driving component on the scraper bracket satisfies the following: the driving component controlling the m-th scraper blade is closer to the central axis of the print head than the driving component controlling the (m+1)-th scraper blade. Each of the scraper blades has a horizontal crossbar fixed to its end, and the dimensions of the horizontal crossbar corresponding to each scraper blade satisfy the following: the dimension of the horizontal crossbar on the m-th scraper blade is greater than the dimension of the horizontal crossbar on the (m+1)-th scraper blade. The traction component is a pair of steel wires. One end of each pair of steel wires is wound around the rotor of the corresponding drive component, passes downward through the wire hole on the horizontal bar corresponding to the (m+1)th scraper blade, and is fixedly connected to the horizontal bar corresponding to the mth scraper blade. The wire pair of the m-th scraper blade is located radially outside the wire pair of the (m+1)-th scraper blade, forming a physical spacing.

[0014] Preferably, the scraper assembly further includes an elastic reset member disposed between adjacent scraper blades and between the scraper blades near the support frame and the support frame, for driving the corresponding scraper blades to reset when the traction member is relaxed; The elastic reset members are arranged between adjacent horizontal crossbars from bottom to top. By controlling the drive unit to retract the traction unit, a pre-compression amount that increases sequentially from bottom to top is applied to each elastic reset member, so that the scraper assembly presents an inwardly curved surface shape in the initial state, and the scraper assemblies on both sides of the rotating frame are symmetrically arranged, presenting a crab claw shape.

[0015] Preferably, the elastic reset element is a spring pair.

[0016] Preferably, the mounting base includes a disc connecting part and a fixed end bracket, the disc connecting part being used to connect the fixed end bracket to the robotic arm of an industrial robot or a three-axis printing actuator; the rotating frame is a rotating end bracket, the rotating end bracket being rotatably connected to the fixed end bracket via bearings; The rotary drive mechanism includes a printhead rotation drive motor, a first gear, and a second gear; the printhead rotation drive motor is fixed on the fixed end bracket, and its output shaft is connected to the first gear; the second gear is connected to the rotating end bracket and meshes with the first gear for transmission.

[0017] Preferably, the lifting mechanism includes a lifting drive unit and a lifting execution unit, wherein the lifting drive unit is a lifting motor; the lifting execution unit includes a driving gear, a driven gear, and a transmission belt surrounding the driving gear and the driven gear; the support frame is connected to the transmission belt through an adapter plate; the lifting motor drives the driven gear by driving the driving gear, thereby causing the transmission belt to move, and the transmission belt drives the support frame connected to it, thereby causing the support frame to perform lifting and lowering movements.

[0018] Preferably, the rotating end bracket has vertically extending guide rails on both sides; the support frame has guide grooves that slide with the guide rails, and the guide rails and guide grooves cooperate to constrain the movement trajectory of the support frame in the vertical direction.

[0019] In addition, the present invention also provides a method for applying a 3D printing head with a dual-sided adjustable curved surface scraper, comprising the following steps: Step S0, Initialization Steps: Control the lifting mechanism of each scraper unit to move the support frame of its corresponding scraper unit to the lowest position; and control the drive component of the deformation mechanism of each scraper unit to release all traction components, so that the scraper assembly of each scraper unit is reset to the bent state under the action of the elastic reset component. At this time, the two scraper units are symmetrically located on both sides of the rotating frame in the shape of crab claws. Step S1, Preparation: The drive component of the control deformation mechanism and the winding traction component cause all the scraper blades in the scraper assembly on both sides of the rotating frame to extend to a vertical working posture. Subsequently, the lifting mechanism of the two sets of scraper units is controlled to simultaneously raise the corresponding support frame to the preset initial working height. The initial working height is such that only the pair of scraper blades in the two sets of scraper units that are far away from the support frame are located on both sides of the print head. Step S2, level in layers: When printing the first layer, maintain the position of the support frame so that the scraper blades away from the support frame are kept on both sides of the print head; As the number of printed layers increases, the lifting mechanism of the two sets of squeegee units is controlled, and the transmission belt of each lifting mechanism is driven to lower the corresponding support frame. This causes the squeegee blades connected to the support frame to be released downwards gradually according to the relationship with the printing layer height, until all the squeegee blades in the squeegee assembly are extended. Step S3, Surface Forming: During the printing process, when the printing path is a curved surface, the drive component of the deformation mechanism is activated according to the preset program, and the corresponding traction component is extended and retracted to the preset length, so as to drive the corresponding scraper blade to deform, so that the overall shape of the scraper assembly fits the curved surface shape to be printed. Step S4, unilateral avoidance: During the printing process, when a new print strip is in close proximity to an already printed strip and creates an obstruction, the lifting mechanism corresponding to the scraper unit on that side is activated to lift the support frame on that side to avoid a collision. Step S5, Orientation Rotation: The control rotary drive mechanism continuously drives the rotating frame to rotate around a set axis, so that the print head moves along the preset printing path and extrudes the printing strip in real time; during the rotation of the rotating frame, the scraper assembly of the scraper unit continuously abuts and trims the two sides of the printing strip, which is still in a viscoelastic state, to achieve continuous dynamic shaping of the curved surface of the printing strip. Meanwhile, since the rotation of the rotating frame is supported by the rotating end bracket, and the orientation of the fixed end bracket and its disc connection remains constant during rotation, the end posture of the industrial robot connected to the fixed end bracket remains unchanged. This avoids the industrial robot from frequently adjusting and resetting its posture during the printing process, thus improving the stability and efficiency of the system operation.

[0020] Secondly, the present invention also provides a control method for a 3D printing head with a dual-sided adjustable curved surface scraper, comprising the following steps: Step S11: Obtain the printed sampling point data Based on the input electronic model and the corresponding print file, the print path is discretely sampled to obtain the print data of each sampling point; The data for each sampling point should include at least the following parameters: {x,y,z,A,B,C,R,L,D1,D2,…,D2N} in: x, y, and z are used to characterize the spatial location of the sampling point; A, B, and C are used to characterize the attitude parameters of the printing actuator at the sampling point; R is used to characterize the lifting state of the scraper mechanism on the right side of the printed wall; L is used to characterize the lifting state of the scraper mechanism on the left side of the printed wall; N represents the number of scraper units on each side; D1 to DN are used to characterize the target length of the steel wire corresponding to the N scraper units on the right; D(N+1) to D(2N) are used to characterize the target length of the steel wire corresponding to the N scraper units on the left. Step S12: Collision Detection For each sampling point, collision detection is performed on the scraper mechanisms on both sides of the printing wall to determine whether the scraper mechanisms on the left and right sides interfere with the structure to be printed, the printed structure, the print head or other components under the current printing posture. When a collision is detected on the left scraper mechanism, set L=True and set the left scraper mechanism to a vertical avoidance state; in this case, the unfolding angle or deformation of each scraper unit on the left is no longer calculated. Similarly, when a collision is detected in the scraper mechanism on the right, R=True is set, and the scraper mechanism on the right is set to a vertical avoidance state; in this case, the unfolding angle or deformation of each scraper unit on the right is no longer calculated. When there is no collision on a certain side of the scraper mechanism, the corresponding flag position is False, and the scraper shape calculation step on that side is entered. Step S13: Determine the shape of the non-collision side scraper sweeping area For the side without collision, the sweeping area of ​​the scraper mechanism at the sampling point is determined based on the printing position parameters and printing posture parameters of the current sampling point, and the matching shape between the scraper sweeping part and the wall surface to be printed is further analyzed. Specifically, based on the local geometric boundary of the printed wall at the sampling point, the print head posture, and the relative installation position of the scraper mechanism, the target contour shape that the scraper needs to adapt to in the current posture is calculated. Step S14: Solving for the position of each scraper unit Based on the target contour shape, calculate the target position, deflection amount or target attitude of each scraper unit on that side, so that the combination of multiple scraper units forms a scraper working boundary that matches the target contour shape. For the side where there is a collision, all scraper units remain vertical and their individual positions are not solved. Step S15: Calculation of wire length Based on the target position, deflection amount or target attitude of each scraper unit, and combined with the geometric relationship of the wire drive mechanism, the target length of the corresponding wire for each scraper unit is calculated. For the non-collision scraper mechanism on the right, the calculated lengths of the N target steel wires are written into D1 to DN in the current sampling point data; For the non-collision scraper mechanism on the left, the calculated lengths of the N target steel wires are written into D(N+1) to D(2N) in the current sampling point data; For the side that is involved in the collision and is set to a vertical state, the length of its steel wire can be set to a preset length corresponding to the vertical state, or the scraper angle on that side can be directly called without dynamically calculating it. Step S16: Generate print data containing scraper control information The collision judgment result, lifting status and target length of each steel wire are written into the corresponding sampling point data to form a print path data file containing deformable scraper control information. Step S17: Print Execution Control During the actual printing process, the control system reads the data from each sampling point sequentially: Based on the target lengths of each steel wire represented by D1 to D2N, drive signals are sent to the corresponding motors controlling each steel wire to adjust the shape of each scraper unit. Based on the states of R and L, a drive signal is sent to the motor that controls the overall lifting of the scraper to control the corresponding scraper mechanism to be in working state or lifting and avoiding state. The above control method enables the deformable scraper mechanism to adaptively adjust its shape under different printing positions and postures, and automatically switch to a vertical avoidance state when there is a risk of collision. This improves the adaptability of the scraper mechanism to the complex wall printing process, reduces the risk of interference, and enhances printing stability and forming quality.

[0021] Preferably, in step S11, the length of the wire corresponding to the nth scraper unit on the right is denoted as Dn, and the length of the wire corresponding to the nth scraper unit on the left is denoted as D(N+n), where n is an integer from 1 to N.

[0022] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention achieves continuous and precise surface deformation capability of the scraper working surface by employing an adjustable curved surface scraper mechanism (deformation mechanism) composed of "rope drive + multi-section hinge + elastic reset". By using multiple independent drive motors mounted on the support frame to raise and lower the traction steel wire, overcoming the elastic force of the spring pairs, the deflection angle of each hinged scraper blade can be independently controlled, allowing multiple scraper blades to combine to form a continuous scraper working surface that perfectly matches the target printed curved surface. This solves the technical problem that existing smoothing mechanisms mostly use flat scrapers or have limited deformation capabilities, making it unable to effectively smooth complex curved surfaces of printed components. Therefore, it can significantly eliminate the "step effect" in curved surface printing, greatly improving the surface finish, dimensional accuracy, and appearance quality of the formed parts.

[0023] 2. This invention achieves independent lifting and lowering control and working length adjustment of the scrapers on both sides by configuring independent lifting mechanisms (lifting mechanisms) for the scraper units on the left and right sides respectively. During the printing process, the lifting mechanism can be controlled to gradually lower the support frame according to the current printing layer height, so that the number of scraper blade sections involved in the work matches the layer height; when interference on one side is detected, the scraper on that side can be raised and lowered separately to avoid it. This solves the technical problems of existing double-sided scraper mechanisms being unable to adapt to the needs of layer printing and being prone to collisions with already printed structures during infill printing or complex paths, greatly improving the adaptability, continuity and safety of the printing process.

[0024] 3. This invention, by setting up a drive mechanism that allows the entire doctor blade unit assembly (rotating frame) to rotate 360 ​​degrees and continuously rotate and align it during printing, ensures that the doctor blade working surface always faces the printing direction. This guarantees that regardless of the curvature of the printing path, both doctor blades will always be positioned on both sides of the newly extruded printing strip and effectively smooth it. This solves the technical problems of some existing single-sided doctor blades or fixed-orientation doctor blades that result in discontinuous smoothing effects during curved printing or require frequent adjustments to the print head posture, thus affecting efficiency. It achieves continuous and stable smoothing throughout the entire path and in all directions.

[0025] 4. This invention integrates the aforementioned deformable, liftable, and rotatable scraper mechanism with the material extrusion mechanism to form a complete intelligent print head. Combined with a control method encompassing path discretization, collision detection, surface solving, drive quantity calculation, and collaborative execution, it achieves intelligent and adaptive surface trimming in extrusion 3D printing (especially architectural 3D printing). This solves the comprehensive technical problems of existing smoothing / scraping mechanisms being bulky, inflexible, and lacking automation, making it difficult to achieve high-quality, high-efficiency surface forming on complex surfaces and paths. It provides a reliable equipment foundation for the automated, high-quality manufacturing of high-end architectural components, irregularly shaped landscape products, and other similar products.

[0026] 5. The control method provided by this invention achieves proactive adaptation of the scraper mechanism to complex printing environments through an intelligent process combining "pre-calculation and online execution." First, the printing path is discretized, and collision detection and surface shape calculation are performed on each path point in advance to generate a control file containing avoidance instructions and target parameters for each drive motor. During actual printing, the system only needs to read and execute these highly reliable instructions sequentially. This solves the technical problem that existing adjustable scrapers, which mostly rely on simple real-time feedback or manual presets, struggle to cope with dynamically changing printing environments (such as the continuously changing printed structure) and complex surfaces. It eliminates interference risks at the planning stage and ensures high precision and reliability in surface forming.

[0027] The aforementioned control method, in deep collaboration with the adjustable curved surface scraper device, transforms the hardware's potential for "multi-degree-of-freedom adjustment" into a stable "high-quality output" capability. This fundamentally solves the technical challenge of engineering and practically applying advanced curved surface scraping concepts, achieving adaptive curved surface scraping. Attached Figure Description

[0028] Figure 1 An isometric schematic diagram of the overall structure of a 3D printing head with a dual-sided adjustable curved surface scraper, provided for an embodiment of the present invention; Figure 2 The image shows a front view of a 3D printing head with a dual-sided adjustable curved scraper, provided in an embodiment of the present invention; wherein the left side view is a cross-sectional view cut along the centerline of its cavity, and the right side view is a front view. Figure 3 The left side view of a 3D printing head with a double-sided adjustable curved scraper provided in an embodiment of the present invention; wherein, the left side view is a cross-sectional view along the middle section of its cavity, and the right side view is the left view; Figure 4 This is a top cross-sectional view of a 3D printing head with a double-sided adjustable curved scraper provided in an embodiment of the present invention. It is a schematic diagram of a section along a certain cross-section of the scraper support. Figure 5 This is a partially enlarged schematic diagram showing the connection between the support frame and the rotating end bracket in a 3D printing head with a double-sided adjustable curved scraper, as provided in an embodiment of the present invention. Figure 6 A schematic diagram illustrating the changes of a 3D printing head with a dual-sided adjustable curved scraper under different working states, provided for an embodiment of the present invention; Figure 7 A schematic diagram illustrating the operation of a 3D printing head with a dual-sided adjustable curved scraper, provided as an embodiment of the present invention; Figure 8A flowchart illustrating a control method for controlling a 3D printing head with a dual-sided adjustable curved surface scraper, provided in an embodiment of the present invention; Figure 9 This invention provides an example of an application of controlling a 3D printing head with a dual-sided adjustable curved scraper in combination with a common existing printing extrusion device.

[0029] The serial numbers in the diagram are as follows: 1. Left scraper blade; 2. Right scraper blade; 3. Left scraper blade; 4. Right scraper blade; 5. Left scraper blade; 5-1. Left scraper blade; 6. Right scraper blade; 7. Left scraper bracket; 8. Right scraper bracket; 9. Left drive motor; 10. Horizontal crossbar; 11. Left drive motor; 12. Horizontal crossbar; 13. Left drive motor; 14. Right drive motor; 15. Left traction wire pair; 16. Right traction wire pair; 17. Left traction wire pair; 18. Right traction wire pair; 19. Left traction wire pair; 21. Left spring pair; 22. Right spring pair; 23. Left spring pair; 24. Right spring pair; 25. Left spring pair; 26. Right spring pair; 27. Rotating end bracket; 28. Cavity 1; 29. ​​Left lifting motor; 30. Right 31. Lifting motor; 32. Left driven gear; 33. Right driven gear; 34. Left driving gear; 35. Right driving gear; 36. Left transmission belt; 37. Right transmission belt; 38. Left guide rail; 39. Left guide groove; 40. Right guide groove; 41. First gear; 42. Second gear; 43. Bearing; 44. Fixed end bracket; 45. Print head rotation drive motor; 46. Material inlet; 47. Cavity 2; 48. Disc connecting part; 49. Adapter plate; 50. Printing strip; 51. Robot connecting part and fixing frame; 52. Printing material storage hopper; 53. Print head extrusion motor; 91. Left rotor 1; 101. Horizontal crossbar 3; 111. Left rotor 2; 121. Horizontal crossbar 4; 131. Left rotor 3; 141. Right rotor 3. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0031] like Figures 1 to 5 As shown, this embodiment provides a 3D printing head with a dual-sided adjustable curved scraper, including a mounting base, a material guide tube, a rotating frame, a scraper unit, a lifting mechanism, and a deformation mechanism. It is fixed to an industrial robotic arm or a three-axis printing actuator via a top disc connection 48.

[0032] like Figure 1 and Figure 2 As shown, the mounting base includes a disc connecting part 48 and a fixed end bracket 44. The disc connecting part 48 is used to reliably connect the entire printhead to the robotic arm of an industrial robot or an external printing actuator, and the fixed end bracket 44 is the main load-bearing and mounting foundation. Figure 9 As shown, the printing material storage hopper 52 is installed on the fixed end bracket 44 and is used to hold the printing material; The printhead extrusion motor 53 is located at the top of the printing material storage hopper 52, and its drive rod extends downward into the printing material storage hopper 52. The end of the drive rod is connected to an extrusion screw or a pusher head, which is used to push the material in the printing material storage hopper 52 downward.

[0033] The robot connection part and the fixed frame 51 are in an L-shaped structure, including a horizontal section and a vertical section. The horizontal section is connected to the print head extrusion motor 53, and the vertical section is connected to the disc connection part 48. The disc connection part 48 is connected to the robot through the vertical section of the robot connection part and the fixed frame 51.

[0034] The material guide tube is used to receive and transport printing material. It includes a material inlet 46, which is connected to an external material pumping line. After the printing material is injected, it first enters cavity 47 within the material inlet 46, then continues to flow downwards into cavity 28 within the rotating frame, and finally is extruded from the extrusion nozzle (not shown in the figure, but a conventional component of the print head) located at the lower end of the rotating frame, thus achieving directional material supply.

[0035] The rotating frame is specifically a rotating end bracket 27, which is rotatably connected to the fixed end bracket 44 via a bearing 43. The upper end of the bearing 43 is fixed to the rotating end bracket 27, and the lower end contacts the fixed end bracket 44, which not only provides reliable support for the rotating end bracket 27, but also ensures that it can rotate smoothly 360° around the fixed end bracket 44.

[0036] To achieve the aforementioned rotation, a rotation drive mechanism is provided on the fixed end bracket 44. The rotation drive mechanism is a printhead rotation drive motor 45, which is mounted on the fixed end bracket 44, and its output shaft is connected to the first gear 41. The first gear 41 meshes with a second gear 42 fixed on the rotating end bracket 27.

[0037] When the printhead rotation drive motor 45 starts, the meshing transmission of the first gear 41 and the second gear 42 can drive the entire rotating end bracket 27 and all the components mounted on it to rotate together, thereby ensuring that the functional components of the printhead are always facing the forward direction when executing a curved path.

[0038] There are two sets of scraper units, namely the left scraper unit and the right scraper unit, which are symmetrically arranged on both sides of the rotating end bracket 27. Each scraper unit independently includes four parts: a support frame, a lifting mechanism, a deformation mechanism, and a scraper assembly.

[0039] The deformation mechanism is used to precisely control the deflection angle of each scraper blade, thereby achieving continuous curved surface deformation of the scraper's working surface. It includes a drive component and a traction component.

[0040] Taking the left side as an example, in the left scraper unit, the driving components of the deformation mechanism are three independent drive motors, namely the first left drive motor 9, the second left drive motor 11, and the third left drive motor 13. These three drive motors are all fixedly mounted on the left scraper bracket 7, which has a U-shaped structure, including a horizontal section and vertical sections connected to its two ends.

[0041] Each drive motor's output shaft is connected to a rotor for winding the traction component. Specifically, the output shaft of the leftmost drive motor 9 is connected to the leftmost rotor 91, the output shaft of the leftmost drive motor 11 is connected to the leftmost rotor 111, and the output shaft of the leftmost drive motor 13 is connected to the leftmost rotor 131. The leftmost drive motor 9 and its rotor 91, the leftmost drive motor 11 and its rotor 111, and the leftmost drive motor 13 and its rotor 131 are all installed between two vertical sections, distributed sequentially from closest to furthest from the horizontal section. That is, the leftmost drive motor 9 is closest to the leftmost scraper support 7 on the horizontal section, i.e., the innermost; the leftmost drive motor 13 is furthest from the leftmost scraper support 7 on the horizontal section, i.e., the outermost; and the leftmost drive motor 11 is located between the leftmost drive motor 9 and the leftmost drive motor 13, i.e., in the middle. Therefore, the leftmost drive motors 9, 11, and 13 are distributed at an angle between the two vertical sections.

[0042] The deformation mechanism has three pairs of traction wires, with two wires in each pair. The three pairs of traction wires are: leftmost traction wire pair 15, leftmost traction wire pair 17, and leftmost traction wire pair 19. One end of leftmost traction wire pair 15 is wound around leftmost rotor 91, and the other end is connected to leftmost scraper blade 1; one end of leftmost traction wire pair 17 is wound around leftmost rotor 111, and the other end is connected to leftmost scraper blade 3; one end of leftmost traction wire pair 19 is wound around leftmost rotor 131, and the other end is connected to leftmost scraper blade 5. By controlling the forward and reverse rotation of the motors of each driving component of the deformation mechanism, the corresponding rotors are driven to rotate to wind or release the corresponding traction wire pairs. This overcomes the elastic force of the corresponding spring pairs, thereby independently and precisely changing the included angles of leftmost scraper blade 1, leftmost scraper blade 3, and leftmost scraper blade 5 relative to adjacent components.

[0043] By coordinating the motor actions of the six drive components of the deformation mechanism, multiple scraper blades can be combined to form a curved scraper working surface that can precisely adapt to the shape of the printed surface.

[0044] The lifting mechanism in each scraper unit is located on the side of the rotating end bracket 27. The two lifting mechanisms are located on the left and right sides of the rotating end bracket 27, respectively, and are used to drive the support frame of the scraper unit to reciprocate in the vertical direction, so as to realize the adjustment and avoidance of the working height of the scraper.

[0045] Furthermore, in this embodiment, the rotating end bracket 27 has vertically extending fixed guide rails on both sides, namely the left guide rail 37 and the right guide rail 38. The left scraper bracket 7 and the right scraper bracket 8 are respectively machined with guide grooves that cooperate with the guide rails, namely the left guide groove 39 and the right guide groove 40. The sliding cooperation between the guide grooves and the guide rails restricts the support frame to move only in the vertical direction, ensuring the accuracy of movement.

[0046] The lifting mechanism includes a lifting drive unit and a lifting actuator unit. Taking the left side as an example, the lifting drive unit is a left lifting motor 29. The lifting actuator unit includes a left driving gear 33, a left driven gear 31, and a left transmission belt 35 surrounding the two. The left transmission belt 35 is connected by an adapter plate 49 (e.g., Figure 5 (As shown) is fixedly connected to the left scraper bracket 7. The output shaft of the left lifting motor 29 drives the left drive gear 33 to rotate, which in turn drives the left transmission belt 35 to move. The left transmission belt 35 then drives the left scraper bracket 7 through the adapter plate 49, causing it to rise and fall along the left guide rail 37.

[0047] The same applies to the right lifting mechanism, which includes a right lifting motor 30, a right driving gear 34, a right driven gear 32, and a right transmission belt 36, and drives the right scraper bracket 8 to rise and fall along the right guide rail 38.

[0048] The scraper assembly in each scraper unit is mounted on its corresponding support frame. The left scraper unit is used as an example; the structure on the right is a mirror image of it.

[0049] In this embodiment, the scraper assembly of the left scraper unit consists of three and a half scraper blades connected in series via hinges (the number of scraper blades can be set according to actual needs; in this embodiment, it is set to three and a half). From bottom to top (i.e., from furthest from the support frame to closest), the three and a half scraper blades are: left scraper blade 1, left scraper blade 3, left scraper blade 5, and left scraper blade 5-1 (half a scraper blade). They are connected in series via freely rotatable hinges, and the left scraper blade 5-1 at the end is hinged to the support frame of the left scraper unit (i.e., the left scraper bracket 7). The right scraper assembly correspondingly includes right scraper blade 2, right scraper blade 4, and right scraper blade 6, and right scraper blade 6 is hinged to the right scraper bracket 8.

[0050] To further optimize the wire routing and avoid interference with the hinge, horizontal crossbars 10, 12, 101, and 121 are sequentially fixed to the ends of the leftmost scraper blade 1, leftmost scraper blade 3, leftmost scraper blade 5, and leftmost scraper blade 5-1 from bottom to top. The dimensions of each horizontal crossbar satisfy the following condition: horizontal crossbar 10 is larger than horizontal crossbar 12, horizontal crossbar 12 is larger than horizontal crossbar 101, and horizontal crossbar 101 is larger than horizontal crossbar 121, presenting a decreasing size gradient from bottom to top. This size gradient ensures that the larger crossbars always radially cover the smaller crossbars, providing physical clearance for the wire.

[0051] The left third traction steel wire pair 19 is led out from the left third rotor 131 of the left third drive motor 13 located on the outermost side, passes down through the pre-set wire hole on the horizontal crossbar 121, and is finally fixedly connected to the horizontal crossbar 101; the left second traction steel wire pair 17 is led out from the left second rotor 111 of the left second drive motor 11 located in the middle side, passes down through the wire hole on the horizontal crossbar 101, and is finally fixedly connected to the horizontal crossbar 12; the left first traction steel wire pair 15 is led out from the left first rotor 91 of the left first drive motor 9 located on the innermost side, passes down through the wire hole on the horizontal crossbar 12, and is finally fixedly connected to the horizontal crossbar 10.

[0052] Furthermore, the fixed position of the left third traction wire pair 19 on the horizontal crossbar 3 101 is different from the position of the left second traction wire pair 17 passing through the wire hole of the horizontal crossbar 3 101, that is, as Figure 1 As shown, the third traction wire pair 19 on the left is located inside the path of the second traction wire pair 17 on the left, so they do not interfere with each other during operation. The fixed position of the second traction wire pair 17 on the horizontal crossbar 12 is different from the position of the first traction wire pair 15 passing through the wire hole of the horizontal crossbar 12. The second traction wire pair 17 on the left is located inside the path of the first traction wire pair 15 on the left, so they do not interfere with each other.

[0053] Through the above-mentioned gradient design of crossbar dimensions (smaller at the top and larger at the bottom) and the corresponding threading path, the threading path of each traction wire maintains a physical gap with the adjacent larger crossbar and hinge shaft during the winding and unwinding process. This completely avoids friction or shear interference between the wire and the moving parts, ensuring the effective transmission of driving force.

[0054] To achieve automatic reset of the scraper blades, the scraper assembly also includes an elastic reset element. In this embodiment, the elastic reset element is preferably a pair of springs. Specifically, in the left scraper assembly, a pair of left springs 21 is fixed between the horizontal crossbar 10 at the end of the left first scraper blade 1 and the horizontal crossbar 22 at the end of the left second scraper blade 3; a pair of left springs 23 is fixed between the horizontal crossbar 22 at the end of the left second scraper blade 3 and the horizontal crossbar 301 at the end of the left third scraper blade 5; and a pair of left springs 25 is fixed between the horizontal crossbar 301 at the end of the left third scraper blade 5 and the left fourth scraper blade 5-1.

[0055] The function of these spring pairs is to apply a pre-compression amount that increases sequentially from bottom to top to each elastic reset member by controlling the drive member to retract the traction member (this pre-compression amount refers to the displacement of the spring compressed by the traction member through the adjacent horizontal crossbar in the initial state, and its magnitude is achieved by controlling the drive member to drive the rotor to retract the traction member), so that the left first scraper blade 1, left second scraper blade 3 and left third scraper blade 5 corresponding to each crossbar present an inward curved surface shape in the initial state, and the scraper assemblies on both sides of the rotating frame are symmetrically arranged, presenting a crab claw shape.

[0056] The right-side scraper assembly is mirror-symmetrical to the left-side scraper assembly. A right-side spring pair 22 is fixed between the horizontal crossbar 5 at the end of the right-side first scraper blade 2 and the horizontal crossbar 6 at the end of the right-side second scraper blade 4. A right-side spring pair 24 is fixed between the horizontal crossbar 6 at the end of the right-side second scraper blade 4 and the horizontal crossbar 7 at the end of the right-side third scraper blade 6. A right-side spring pair 26 is fixed between the horizontal crossbar 7 at the end of the right-side third scraper blade 6 and the right-side scraper bracket 8. Similarly, by controlling the right-side drive unit's winding traction unit, a pre-compression amount that increases sequentially from bottom to top is applied to the right-side spring pair 22, the right-side spring pair 24, and the right-side spring pair 26, so that the right-side first scraper blade 2, the right-side second scraper blade 4, and the right-side third scraper blade 6 initially exhibit an inwardly curved surface shape.

[0057] The deformation mechanism of the right scraper unit is mirror-symmetrical to the deformation mechanism of the left scraper unit, and its structure and working principle are the same as those on the left.

[0058] Specifically, the driving components of the right scraper unit include a right-first drive motor, a right-second drive motor, and a right-third drive motor 14, with the output shafts of each drive motor connected to the right-first rotor, the right-second rotor, and the right-third rotor 141, respectively. The traction components include a right-first traction wire pair 16, a right-second traction wire pair 18, and a right-third traction wire pair.

[0059] The connection relationship, routing path, and avoidance principle of the right first traction steel wire pair 16, the right second traction steel wire pair 18, and the right third traction steel wire pair are the same as those on the left side. That is, the horizontal crossbar size gradient of small upper and large lower is adopted so that the steel wire maintains a physical gap with the adjacent crossbar and hinge shaft during the winding and unwinding process to avoid interference.

[0060] By controlling the forward and reverse rotation of each drive motor on the right, the included angles of the first right scraper blade 2, the second right scraper blade 4, and the third right scraper blade 6 can also be changed independently.

[0061] In addition, such as Figures 6 to 9 As shown, this embodiment provides an application method for a 3D printing head with a dual-sided adjustable curved surface scraper, including the following steps: Step S0, Initialization Steps: Control the lifting mechanism of each group of scraper units to move the support frame of the corresponding scraper unit to the lowest position; and control the drive component of the deformation mechanism of each group of scraper units to release all traction components, so that the scraper assembly of each group of scraper units is reset to the bent state under the action of the elastic reset component. At this time, the two groups of scraper units are symmetrically located on both sides of the rotating frame in the shape of crab claws. Step S1, Preparation Steps: The drive component of the deformation mechanism is controlled to retract the traction component, so that all the scraper blades in the scraper assembly on both sides of the rotating frame extend to a vertical working posture. Subsequently, the lifting mechanisms of the two sets of scraper units are controlled to synchronously raise the corresponding support frames to a preset initial working height. The initial working height is such that only one pair of scraper blades in the two sets of scraper units that are far from the support frame are located on both sides of the print head. Specifically, the left lifting motor 29 and the right lifting motor 30 are started, driving the corresponding rotors to rotate, driving the left transmission belt 35 and the right transmission belt 36, lifting the left scraper bracket 7 and the right scraper bracket 8, so that the scrapers corresponding to the left scraper bracket 7 and the right scraper bracket 8 are lifted, and only the left scraper blade 1 and the right scraper blade 2 are left on both sides of the print head. Step S2, layered leveling step: When printing the first layer, maintain the position of the support frame so that the scraper blades away from the support frame are kept on both sides of the print head; As the number of printed layers increases, the lifting mechanisms of the two sets of scraper units are controlled, and the transmission belt of each set of lifting mechanisms is driven to lower the corresponding support frame. This causes the scraper blades connected to the support frame to be released downwards gradually according to the relationship with the printing layer height, until all the scraper blades in the scraper assembly are extended. Step S3, Surface Forming Step: During the printing process, when the printing path is a curved surface, the drive component of the deformation mechanism is activated according to a preset program, and the corresponding traction component is extended or retracted to a preset length to drive the corresponding scraper blade to deform, so that the overall shape of the scraper assembly conforms to the desired curved surface shape to be printed. Step S4, unilateral avoidance steps: During the printing process, when a new print strip is in close proximity to an already printed strip and creates an obstruction, the lifting mechanism corresponding to the scraper unit on that side is activated to lift the support frame on that side to avoid a collision. Step S5, Orientation and Rotation Step: like Figure 7 As shown, the rotary drive mechanism continuously drives the rotating frame to rotate around a set axis, so that the print head moves along a preset printing path and extrudes the printing strip 50 in real time; during the rotation of the rotating frame, the scraper assembly of the scraper unit continuously abuts and trims the two sides of the printing strip 50, which is still in a viscoelastic state, to achieve continuous dynamic shaping of the curved surface of the printing strip. Meanwhile, since the rotation of the rotating frame is supported by the rotating end bracket 27, and the orientation of the fixed end bracket 44 and its disc connecting part 48 remains constant during rotation, the end posture of the industrial robot connected to the fixed end bracket 44 remains unchanged, thereby avoiding frequent posture adjustments and resets of the industrial robot during the printing process, and improving the stability and efficiency of the system operation.

[0062] in, Figure 6 In the diagram, a represents state 0 (non-working collapsed state), b represents state 1 (printing ready state), d represents state 3 (curved surface adaptive leveling state), and c represents state 4 (single-sided avoidance state). In addition, such as Figure 8 As shown, this embodiment also provides a control method for a 3D printing head with a dual-sided adjustable curved surface scraper, including the following steps: Step S11: Obtain the printed sampling point data Based on the input electronic model and the corresponding print file, the print path is discretely sampled to obtain the print data of each sampling point; The data for each sampling point should include at least the following parameters: {x,y,z,A,B,C,R,L,D1,D2,...,D2N} in: x, y, and z are used to characterize the spatial location of the sampling point; A, B, and C are used to characterize the attitude parameters of the printing actuator at the sampling point; R is used to characterize the lifting state of the scraper mechanism on the right side of the printed wall; L is used to characterize the lifting state of the scraper mechanism on the left side of the printed wall; N represents the number of scraper units on each side; D1 to DN are used to characterize the target length of the steel wire corresponding to the N scraper units on the right; D(N+1) to D(2N) are used to characterize the target length of the steel wire corresponding to the N scraper units on the left. Furthermore, in this embodiment, the length of the wire corresponding to the nth scraper unit on the right is denoted as Dn, and the length of the wire corresponding to the nth scraper unit on the left is denoted as D(N+n), where n is an integer from 1 to N.

[0063] Step S12: Collision Detection For each sampling point, collision detection is performed on the scraper mechanisms on both sides of the printing wall to determine whether the scraper mechanisms on the left and right sides interfere with the structure to be printed, the printed structure, the print head or other components under the current printing posture. When a collision is detected on the left scraper mechanism, set L=True and set the left scraper mechanism to a vertical avoidance state; in this case, the unfolding angle or deformation of each scraper unit on the left is no longer calculated. Similarly, when a collision is detected in the scraper mechanism on the right, R=True is set, and the scraper mechanism on the right is set to a vertical avoidance state; in this case, the unfolding angle or deformation of each scraper unit on the right is no longer calculated. When there is no collision on a certain side of the scraper mechanism, the corresponding flag position is False, and the scraper shape calculation step on that side is entered. Step S13: Determine the shape of the non-collision side scraper sweeping area For the side without collision, the sweeping area of ​​the scraper mechanism at the sampling point is determined based on the printing position parameters and printing posture parameters of the current sampling point, and the matching shape between the scraper sweeping part and the wall surface to be printed is further analyzed. Furthermore, based on the local geometric boundary of the printed wall at the sampling point, the print head posture, and the relative installation position of the scraper mechanism, the target contour shape that the scraper needs to adapt to in the current posture is calculated. Step S14: Solving for the position of each scraper unit Based on the target contour shape, calculate the target position, deflection amount or target orientation of each scraper unit on that side, so that multiple scraper units are combined to form a scraper working boundary that matches the target contour shape; For the side where there is a collision, all scraper units remain vertical and their individual positions are not solved. Step S15: Calculation of wire length Based on the target position, deflection amount or target attitude of each scraper unit, and combined with the geometric relationship of the wire drive mechanism, the target length of the corresponding wire for each scraper unit is calculated. For the non-collision scraper mechanism on the right, the calculated lengths of the N target steel wires are written into D1 to DN in the current sampling point data; For the non-collision scraper mechanism on the left, the calculated lengths of the N target steel wires are written into D(N+1) to D(2N) in the current sampling point data; For the side that is involved in the collision and is set to a vertical state, the length of its steel wire can be set to a preset length corresponding to the vertical state, or the scraper angle on that side can be directly called without dynamically calculating it. Step S16: Generate print data containing scraper control information The collision judgment result, lifting status and target length of each steel wire are written into the corresponding sampling point data to form a print path data file containing deformable scraper control information. Step S17: Print Execution Control During the actual printing process, the control system reads the data from each sampling point sequentially: Based on the target lengths of each steel wire represented by D1 to D2N, drive signals are sent to the corresponding motors controlling each steel wire to adjust the shape of each scraper unit. Based on the states of R and L, a drive signal is sent to the motor that controls the overall lifting of the scraper to control the corresponding scraper mechanism to be in working state or lifting and avoiding state. The above control method enables the deformable scraper mechanism to adaptively adjust its shape under different printing positions and postures, and automatically switch to a vertical avoidance state when there is a risk of collision. This improves the adaptability of the scraper mechanism to the complex wall printing process, reduces the risk of interference, and enhances printing stability and forming quality.

[0064] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0065] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0066] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A 3D printing head with a dual-sided adjustable curved scraper, characterized in that, Includes mounting base, material guide tube, rotating frame, scraper unit, lifting mechanism and deformation mechanism; The mounting base is used to connect to an external printing actuator; The material guide tube is disposed on the rotating frame, and a through channel is formed inside it for material to pass through, which is used to guide the raw material from the upper feeding system to the lower print head; The rotating frame is connected to the mounting base, and the mounting base is provided with a rotation drive mechanism that drives the rotating frame to rotate around its axis. The scraper unit consists of two sets, which are respectively arranged on both sides of the rotating frame; Each scraper unit includes a support frame, a lifting mechanism, a deformation mechanism, and a scraper assembly; The lifting mechanism is located on the side of the rotating frame, connected to the support frame, and drives the support frame to reciprocate in the vertical direction. The scraper assembly, which is mounted on the support frame, includes a plurality of scraper blades connected in series by hinges, and the scraper blades close to the support frame are hinged to the support frame. The deformation mechanism includes a driving component and a traction component; the driving component is mounted on the support frame; the traction component is used to connect the driving component to a corresponding scraper blade in the scraper assembly; The drive components of the rotary drive mechanism, lifting mechanism, and deformation mechanism are each independent drive sources; the drive component of the deformation mechanism controls the extension and retraction of the traction component, changing the deflection angle of the corresponding scraper blade, thereby enabling multiple scraper blades to form an adjustable curved scraper working surface.

2. The 3D printing head with a dual-sided adjustable curved scraper according to claim 1, characterized in that, The support frame is a scraper bracket, and the scraper assembly includes at least three scraper blades connected in series by hinges, which are defined as the first scraper blade, the second scraper blade, ... the mth scraper blade in sequence from the direction away from the scraper bracket to the direction closer to the scraper bracket; The number of driving components of the deformation mechanism is the same as the number of scraper blades, and the driving component of each deformation mechanism is disposed on the scraper bracket; and the installation position of each driving component on the scraper bracket satisfies the following: the driving component controlling the m-th scraper blade is closer to the central axis of the print head than the driving component controlling the (m+1)-th scraper blade. Each of the scraper blades has a horizontal crossbar fixed to its end, and the dimensions of the horizontal crossbar corresponding to each scraper blade satisfy the following: the dimension of the horizontal crossbar on the m-th scraper blade is greater than the dimension of the horizontal crossbar on the (m+1)-th scraper blade. The traction component is a pair of steel wires. One end of each pair of steel wires is wound around the rotor of the corresponding drive component, passes downward through the wire hole on the horizontal bar corresponding to the (m+1)th scraper blade, and is fixedly connected to the horizontal bar corresponding to the mth scraper blade. The wire pair of the m-th scraper blade is located radially outside the wire pair of the (m+1)-th scraper blade, forming a physical spacing.

3. The 3D printing head with a dual-sided adjustable curved scraper according to claim 2, characterized in that, The scraper assembly also includes an elastic reset member disposed between adjacent scraper blades and between the scraper blades near the support frame and the support frame, for driving the corresponding scraper blades to reset when the traction member is relaxed; The elastic reset members are arranged between adjacent horizontal crossbars from bottom to top. By controlling the drive unit to retract the traction unit, a pre-compression amount that increases sequentially from bottom to top is applied to each elastic reset member, so that the scraper assembly presents an inwardly curved surface shape in the initial state, and the scraper assemblies on both sides of the rotating frame are symmetrically arranged, presenting a crab claw shape.

4. The 3D printing head with a dual-sided adjustable curved scraper according to claim 3, characterized in that, The elastic reset element uses a spring pair.

5. The 3D printing head with a dual-sided adjustable curved scraper according to claim 1, characterized in that, The mounting base includes a disc connecting part (48) and a fixed end bracket (44). The disc connecting part (48) is used to connect the fixed end bracket (44) to the robotic arm of an industrial robot or a three-axis printing actuator. The rotating frame is a rotating end bracket (27), which is rotatably connected to the fixed end bracket (44) via a bearing (43). The rotary drive mechanism includes a printhead rotation drive motor (45), a first gear (41), and a second gear (42); the printhead rotation drive motor (45) is fixed on the fixed end bracket (44), and its output shaft is connected to the first gear (41); the second gear (42) is connected to the rotating end bracket (27) and meshes with the first gear (41) for transmission.

6. The 3D printing head with a dual-sided adjustable curved scraper according to claim 1, characterized in that, The lifting mechanism includes a lifting drive unit and a lifting execution unit. The lifting drive unit is a lifting motor. The lifting execution unit includes a driving gear, a driven gear, and a transmission belt surrounding the driving gear and the driven gear. The support frame is connected to the transmission belt through a transition plate (49). The lifting motor drives the driven gear by driving the driving gear, which causes the transmission belt to move. The transmission belt drives the support frame connected to it, causing the support frame to move up and down.

7. The 3D printing head with a dual-sided adjustable curved scraper according to claim 5, characterized in that, The rotating end bracket (27) is provided with vertically extending guide rails on both sides; the support frame is provided with guide grooves that slide with the guide rails, and the guide rails and guide grooves cooperate to constrain the movement trajectory of the support frame in the vertical direction.

8. A method for applying a 3D printing head with a dual-sided adjustable curved surface scraper based on any one of claims 1-7, characterized in that, Includes the following steps: Step S0, Initialization Steps: Control the lifting mechanism of each scraper unit to move the support frame of its corresponding scraper unit to the lowest position; and control the drive component of the deformation mechanism of each scraper unit to release all traction components, so that the scraper assembly of each scraper unit is reset to the bent state under the action of the elastic reset component. At this time, the two scraper units are symmetrically located on both sides of the rotating frame in the shape of crab claws. Step S1, Preparation: The drive component of the control deformation mechanism and the winding traction component cause all the scraper blades in the scraper assembly on both sides of the rotating frame to extend to a vertical working posture. Subsequently, the lifting mechanism of the two sets of scraper units is controlled to simultaneously raise the corresponding support frame to the preset initial working height. The initial working height is such that only the pair of scraper blades in the two sets of scraper units that are far away from the support frame are located on both sides of the print head. Step S2, level in layers: When printing the first layer, maintain the position of the support frame so that the scraper blades away from the support frame are kept on both sides of the print head; As the number of printed layers increases, the lifting mechanism of the two sets of squeegee units is controlled, and the transmission belt of each lifting mechanism is driven to lower the corresponding support frame. This causes the squeegee blades connected to the support frame to be released downwards gradually according to the relationship with the printing layer height, until all the squeegee blades in the squeegee assembly are extended. Step S3, Surface Forming: During the printing process, when the printing path is a curved surface, the drive component of the deformation mechanism is activated according to the preset program, and the corresponding traction component is extended and retracted to the preset length, so as to drive the corresponding scraper blade to deform, so that the overall shape of the scraper assembly fits the curved surface shape to be printed. Step S4, unilateral avoidance: During the printing process, when a new print strip is in close proximity to an already printed strip and creates an obstruction, the lifting mechanism corresponding to the scraper unit on that side is activated to lift the support frame on that side to avoid a collision. Step S5, Orientation Rotation: The control rotary drive mechanism continuously drives the rotating frame to rotate around the set axis, so that the print head moves along the preset printing path and extrudes the printing strip (50) in real time; during the rotation of the rotating frame, the scraper assembly of the scraper unit continuously abuts and trims the two sides of the printing strip (50) which is still in a viscoelastic state, so as to realize the continuous dynamic shaping of the curved surface of the printing strip. Meanwhile, the orientation of the fixed end bracket (44) and the disk connecting part (48) on it remains constant during rotation, so that the end posture of the industrial robot connected to the fixed end bracket (44) remains unchanged.

9. A control method for a 3D printing head with double-sided adjustable curved blades according to any one of claims 1-7, characterized in that, Includes the following steps: Step S11: Obtain the printed sampling point data Based on the input electronic model and the corresponding print file, the print path is discretely sampled to obtain the print data of each sampling point; The data for each sampling point should include at least the following parameters: {x,y,z,A,B,C,R,L,D1,D2,...,D2N} in: x, y, and z are used to characterize the spatial location of the sampling point; A, B, and C are used to characterize the attitude parameters of the printing actuator at the sampling point; R is used to characterize the lifting state of the scraper mechanism on the right side of the printed wall; L is used to characterize the lifting state of the scraper mechanism on the left side of the printed wall; N represents the number of scraper units on each side; D1 to DN are used to characterize the target length of the steel wire corresponding to the N scraper units on the right; D(N+1) to D(2N) are used to characterize the target length of the steel wire corresponding to the N scraper units on the left. Step S12: Collision Detection For each sampling point, collision detection is performed on the scraper mechanisms on both sides of the printing wall to determine whether the scraper mechanisms on the left and right sides interfere with the structure to be printed, the printed structure, the print head or other components under the current printing posture. When a collision is detected on the left scraper mechanism, set L=True and set the left scraper mechanism to a vertical avoidance state; in this case, the unfolding angle or deformation of each scraper unit on the left is no longer calculated. Similarly, when a collision is detected in the scraper mechanism on the right, R=True is set, and the scraper mechanism on the right is set to a vertical avoidance state; in this case, the unfolding angle or deformation of each scraper unit on the right is no longer calculated. When there is no collision on a certain side of the scraper mechanism, the corresponding flag position is False, and the scraper shape calculation step on that side is entered. Step S13: Determine the shape of the non-collision side scraper sweeping area For the side without collision, the sweeping area of ​​the scraper mechanism at the sampling point is determined based on the printing position parameters and printing posture parameters of the current sampling point, and the matching shape between the scraper sweeping part and the wall surface to be printed is further analyzed. Specifically, based on the local geometric boundary of the printed wall at the sampling point, the print head posture, and the relative installation position of the scraper mechanism, the target contour shape that the scraper needs to adapt to in the current posture is calculated. Step S14: Solving for the position of each scraper unit Based on the target contour shape, calculate the target position, deflection amount or target attitude of each scraper unit on that side, so that the combination of multiple scraper units forms a scraper working boundary that matches the target contour shape. For the side where there is a collision, all scraper units remain vertical and their individual positions are not solved. Step S15: Calculation of wire length Based on the target position, deflection amount or target attitude of each scraper unit, and combined with the geometric relationship of the wire drive mechanism, the target length of the corresponding wire for each scraper unit is calculated. For the non-collision scraper mechanism on the right, the calculated lengths of the N target steel wires are written into D1 to DN in the current sampling point data; For the non-collision scraper mechanism on the left, the calculated lengths of the N target steel wires are written into D(N+1) to D(2N) in the current sampling point data; For the side that is involved in the collision and is set to a vertical state, the length of its steel wire can be set to a preset length corresponding to the vertical state, or the scraper angle on that side can be directly called without dynamically calculating it. Step S16: Generate print data containing scraper control information The collision judgment result, lifting status and target length of each steel wire are written into the corresponding sampling point data to form a print path data file containing deformable scraper control information. Step S17: Print Execution Control During the actual printing process, the control system reads the data from each sampling point sequentially: Based on the target lengths of each steel wire represented by D1 to D2N, drive signals are sent to the corresponding motors controlling each steel wire to adjust the shape of each scraper unit. Based on the states of R and L, a drive signal is sent to the motor that controls the overall lifting of the scraper to control the corresponding scraper mechanism to be in working state or lifting and avoiding state. The above control method enables the deformable scraper mechanism to adaptively adjust its shape under different printing positions and postures, and automatically switch to a vertical avoidance state when there is a risk of collision.

10. The method of claim 9, wherein the method further comprises: In step S11, the length of the wire corresponding to the nth scraper unit on the right is denoted as Dn, and the length of the wire corresponding to the nth scraper unit on the left is denoted as D(N+n), where n is an integer from 1 to N.

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