A method and device for 4D printing of a soft material with regionalized magnetic domain direction

Abstract

The application discloses a kind of soft material 4D printing method and device with regionalized magnetic domain direction.The method comprises the following steps: establishing partition three-dimensional model and planning printing path to generate original G code;Based on the preset magnetic domain direction requirement, obtain the driving parameters of multiple magnetic poles by magnetic field model reverse decoupling, and re-edit G code to integrate magnetic field control and UV light control instruction;Prepare UV-curable soft material containing magnetic particles;After setting printing parameters, execute printing, synthesize three-dimensional magnetic field of preset direction at extrusion point when material extrusion makes magnetic particles directional, and delay to open UV light curing to lock magnetic domain direction.The application realizes three-dimensional space regionalization editing of magnetic domain direction inside soft material, significantly improves the deformation design freedom and motion control accuracy of 4D printing product, and provides reliable technical support for integrated manufacturing of complex driven soft robot.

Description

Technical Field

[0001] This invention relates to the fields of smart materials and additive manufacturing technology, and in particular to a method and apparatus for 4D printing soft materials with regionalized magnetic domain orientation. Background Technology

[0002] Building upon 3D printing technology, the introduction of intelligent materials capable of controlled deformation under external stimuli constitutes 4D printing technology. This technology introduces the time dimension into the product lifecycle, enabling static structures to autonomously evolve into dynamic functional systems under predetermined environmental stimuli, achieving a breakthrough from manufacturing to growth. Among these advancements, the use of soft materials as magnetic particle carriers to manufacture magnetically driven soft robots via 4D printing is a research hotspot in this field. Soft materials possess high flexibility, large deformation capacity, and good biocompatibility, making them ideal carriers for achieving complex actuation and deformation.

[0003] However, current technologies suffer from a severe lack of control over the orientation of magnetic domains within materials during the printing process. Most mainstream magnetization methods employ global, static magnetic fields, such as uniformly solidifying the entire component within a single-directional magnetic field, or only achieving simple orientation along the printing path. This method has a fundamental limitation: it cannot create complex magnetic domain patterns that vary with three-dimensional space within the component. This results in a limited range of structural deformation patterns in the printed structure, severely restricting the functional diversity and application potential of 4D printed soft structures. Although some research has attempted to introduce computer control, how to edit and lock the magnetic field orientation at any point in three-dimensional space in real-time and with precision during a continuous printing process remains an unresolved technological bottleneck.

[0004] Therefore, how to achieve 4D printing with magnetic domain editing at any angle and in any direction in space, and improve the freedom of deformation design and the precision of motion control of 4D printed products, is a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a method and apparatus for 4D printing soft materials with regionalized magnetic domain orientation, which can realize 4D printing with magnetic domain editing at any angle and in any direction in space, thereby improving the degree of freedom of deformation design and the accuracy of motion control of 4D printed products.

[0006] The first aspect of this invention provides a method for 4D printing soft materials with regionalizable magnetic domain orientations, comprising:

[0007] Create a partitioned 3D model of the object to be printed using 3D modeling software;

[0008] Import the partitioned 3D model into the slicing software to perform regional printing path planning and generate the original G-code.

[0009] Based on the preset regional magnetic domain direction requirements, the driving parameters of multiple magnetic poles are obtained by reverse decoupling through the magnetic field model. The original G code is then re-edited, and the driving parameter instructions and ultraviolet switch instructions are integrated into the original G code to obtain the control G code.

[0010] Prepare a UV-curable soft material containing magnetic particles and load it into the printing syringe of a 4D printer;

[0011] Set printing process parameters;

[0012] The printing process is executed according to the control G code. During material extrusion, multiple magnetic fields are coupled at the extrusion point to synthesize a three-dimensional magnetic field in a preset direction, causing magnetic particles to align in the direction of the magnetic field to form target magnetic domains. After a preset delay time, the UV curing material is turned on to lock the magnetic domain direction, thereby obtaining a soft 4D printed product with a regionalized magnetic domain direction.

[0013] Optionally, the original G-code is re-edited to integrate the drive parameter instructions and ultraviolet switch instructions into the original G-code, resulting in control G-code, including:

[0014] A control strategy based on physical space gridding is adopted to divide the printing platform into multiple grid cells;

[0015] Based on the projection of the partitioned 3D model onto the printing platform and the correspondence between multiple grid cells, and combined with the preset magnetic domain direction requirements for each region, specific magnetic field control parameters are set for each grid cell covered by the partitioned 3D model.

[0016] The magnetic field control parameters are converted into corresponding voltage control commands through a post-processing script.

[0017] The voltage control command and the ultraviolet switch command are integrated into the original G code to obtain the control G code.

[0018] Optionally, based on preset regional magnetic domain orientation requirements, the driving parameters of multiple magnetic poles are obtained through reverse decoupling using a magnetic field model, including:

[0019] Define the direction vector of the target's total magnetic field in spherical coordinates;

[0020] Convert the direction vector into magnetic field components in a Cartesian coordinate system;

[0021] Based on the spatial position and magnetic field strength model of each magnetic pole, the required driving current value of each magnetic pole is solved in reverse according to the magnetic field components.

[0022] The drive current value is converted into the corresponding voltage control command, thereby obtaining the drive parameters for multiple magnetic poles.

[0023] Optionally, multiple magnetic fields are generated by three magnetizing coils, which are arranged around the material extrusion point at a uniform angle of 120°. The magnetic field generation directions of the three magnetizing coils are orthogonal to each other in three-dimensional space, and the end of the magnetic core of each magnetizing coil maintains a predetermined working distance from the extrusion point.

[0024] Optionally, a UV-curable soft material containing magnetic particles is prepared, comprising:

[0025] Select permanent magnet material powder and UV-curable polymer matrix;

[0026] The permanent magnet material powder and the UV-cured polymer matrix are mixed and stirred evenly according to a predetermined mass ratio;

[0027] The mixed materials are subjected to vacuum treatment to remove air bubbles;

[0028] After removing air bubbles, the mixed material is left to stand for a predetermined time to obtain a uniform and printable UV-curable soft material containing magnetic particles.

[0029] Optionally, the UV-cured material is activated after a preset delay time, including:

[0030] The UV irradiation head is activated after a predetermined delay following the start of material extrusion.

[0031] Based on the curing characteristics of UV-curable soft materials, the wavelength of UV light, the irradiation diameter, and the distance between the UV irradiation head and the material extrusion point are adapted and set.

[0032] Optionally, printing process parameters can be set, including:

[0033] The printing process parameters are synergistically optimized based on the rheological properties of the UV-curable soft material and the response characteristics of the magnetic particles. These parameters include printing speed, extrusion flow rate, and the range of magnetic field strength at the extrusion point.

[0034] A second aspect of the present invention provides a 4D printing apparatus for soft materials with regionalizable magnetic domain orientation, comprising:

[0035] Modeling unit, used to create a partitioned 3D model of the object to be printed using 3D modeling software;

[0036] The planning unit is used to import the partitioned 3D model into the slicing software for regional printing path planning and to generate the original G-code.

[0037] The reprogramming unit is used to obtain the driving parameters of multiple magnetic poles by reverse decoupling through the magnetic field model based on the preset regional magnetic domain direction requirements, and to re-edit the original G code, integrating the driving parameter instructions and ultraviolet switch instructions into the original G code to obtain the control G code;

[0038] The preparation unit is used to prepare UV-cured soft materials containing magnetic particles and load them into the printing syringe of a 4D printer.

[0039] The settings unit is used to set printing process parameters;

[0040] The printing unit is used to execute the printing process according to the control G code. When the material is extruded, multiple magnetic fields are coupled at the extrusion point to synthesize a three-dimensional magnetic field in a preset direction, so that the magnetic particles are oriented along the magnetic field direction to form target magnetic domains. After a preset delay time, the UV curing material is turned on to lock the magnetic domain direction, so as to obtain a soft 4D printed product with a regionalized magnetic domain direction.

[0041] A third aspect of the present invention provides a 4D printing apparatus for soft materials with regionalizable magnetic domain orientation, comprising:

[0042] One or more processors;

[0043] A memory on which one or more programs are stored;

[0044] When the one or more programs are executed by the one or more processors, the one or more processors implement the method for 4D printing soft materials with zonal magnetic domain orientation as described in any of the preceding claims.

[0045] A fourth aspect of the present invention provides a computer storage medium for storing a program, which, when executed, is used to implement a method for 4D printing of soft materials with zonal magnetic domain orientation as described in any of the preceding claims.

[0046] This invention discloses a method, apparatus, and equipment for 4D printing soft materials with regionalized magnetic domain orientation, belonging to the field of smart materials and additive manufacturing technology. The method includes: establishing a partitioned 3D model and planning the printing path to generate original G-code; based on preset magnetic domain orientation requirements, obtaining driving parameters for multiple magnetic poles through inverse decoupling of the magnetic field model, and re-editing the G-code to integrate magnetic field control and UV light control instructions; preparing a UV-curable soft material containing magnetic particles; setting printing parameters and executing printing, synthesizing a 3D magnetic field with a preset orientation at the extrusion point during material extrusion to orient the magnetic particles, and delaying the start of UV curing to lock the magnetic domain orientation. This invention achieves 3D spatial regional editing of the magnetic domain orientation within the soft material, significantly improving the deformation design freedom and motion control accuracy of 4D printed products, and providing reliable technical support for the integrated manufacturing of complex driven soft robots. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a flowchart illustrating a method for 4D printing soft materials with regionalized magnetic domain orientation, provided in an embodiment of the present invention.

[0049] Figure 2 This is a schematic diagram illustrating the principle of a 4D printing method for soft materials with regionalized magnetic domain orientation provided in an embodiment of the present invention.

[0050] Figure 3 This is a schematic diagram of a magnetic domain direction editing device provided in an embodiment of the present invention;

[0051] Figure 4 A schematic diagram of a 4D printing process provided in an embodiment of the present invention;

[0052] Figure 5 This is a schematic diagram of a magnetic field direction coordinate system transformation provided in an embodiment of the present invention;

[0053] Figure 6 A comparison diagram of printing effects with different delay times provided for an embodiment of the present invention;

[0054] Figure 7 This is a schematic diagram of the structure of a soft material 4D printing method device with regionalizable magnetic domain orientation provided in an embodiment of the present invention;

[0055] Figure 8 This is a schematic diagram of the structure of a soft material 4D printing method and equipment with regionalized magnetic domain orientation provided in an embodiment of the present invention. Detailed Implementation

[0056] This invention provides a method and apparatus for 4D printing soft materials with regionalized magnetic domain orientation, which can realize 4D printing with magnetic domain editing at any angle and in any direction in space, thereby improving the degree of freedom of deformation design and the accuracy of motion control of 4D printed products.

[0057] See Figure 1 This figure is a schematic flowchart of a 4D printing method for soft materials with regionalized magnetic domain orientation provided by an embodiment of the present invention. The 4D printing method for soft materials with regionalized magnetic domain orientation provided by this embodiment of the present invention can be implemented, for example, through the following steps S101-106.

[0058] Combination Figure 2 Please provide an explanation, such as Figure 2 As shown in the figure, this is a schematic diagram of the principle of a soft material 4D printing method with regionalized magnetic domain orientation provided by an embodiment of the present invention. First, a partitioned 3D model of the object to be printed is established and the parts are designed using 3D modeling software (such as SolidWorks / CATIA / UG). The figure clearly shows multiple separate part structures. Then, the established model is imported into slicing software for assembly and regionalized printing path planning, generating the original G-code. The planned printing path is clearly shown in the figure through stripes. Then, the magnetic field model is decoupled in reverse to obtain the driving parameters of each magnetic pole, and the G-code is re-edited using a control strategy based on physical space gridding, integrating magnetic field control instructions and UV light switching instructions. During the printing process, three orthogonally arranged magnetic coils couple at the extrusion point to generate a 3D magnetic field with a preset direction, causing the magnetic particles to be oriented to form the target magnetic domain. The arrows in the figure indicate the direction and state changes of the magnetic coils. After a preset delay, the UV curing material is turned on, and finally a 4D printed product that can exhibit specific complex deformations under the drive of an external magnetic field is obtained. The product structure shown in the figure has changed significantly, forming a complex spatial configuration. The entire process, from "design → assembly → printing planning → magnetic coding operation → magnetic field driven deformation," fully presents the implementation process of regional magnetic domain editing 4D printing technology.

[0059] S101: Create a partitioned 3D model of the object to be printed using 3D modeling software.

[0060] In this embodiment of the invention, a 3D model is created using 3D modeling software according to requirements. Since the printing routing direction needs to be edited in the slicing software later, the model is generally created in sections. In this embodiment of the invention, 3D modeling can be performed using 3D modeling software such as SolidWorks, CATIA, or UG to model the target shape of the object to be printed. Sectional modeling is used according to different routing methods to achieve regionalized shapes.

[0061] S102: Import the partitioned 3D model into the slicing software to perform regional printing path planning and generate the original G-code.

[0062] In this embodiment of the invention, the established partitioned 3D model is imported into the slicing software in STL format, assembled in the slicing software, and then the printing path is edited according to different areas to generate the original file of G code (G01 XY Z).

[0063] S103: Based on the preset regional magnetic domain direction requirements, the driving parameters of multiple magnetic poles are obtained by reverse decoupling through the magnetic field model, and the original G code is re-edited to integrate the driving parameter instructions and ultraviolet switch instructions into the original G code to obtain the control G code.

[0064] In this embodiment of the invention, the direction vector of the target total magnetic field in the spherical coordinate system is set; the direction vector is converted into magnetic field components in the rectangular coordinate system; based on the spatial position and magnetic field strength model of each magnetic pole, the required driving current value of each magnetic pole is solved in reverse according to the magnetic field components; the driving current value is converted into the corresponding voltage control command, thereby obtaining the driving parameters of multiple magnetic poles.

[0065] A physical space grid-based control strategy is adopted, dividing the printing platform into multiple grid cells. Based on the correspondence between the projection of the partitioned 3D model on the printing platform and the multiple grid cells, and combined with the preset magnetic domain direction requirements for each region, specific magnetic field control parameters are set for each grid cell covered by the partitioned 3D model. The magnetic field control parameters are converted into corresponding voltage control instructions through a post-processing script. The voltage control instructions and ultraviolet switch instructions are integrated into the original G-code to obtain the control G-code.

[0066] Specifically, based on the different requirements of the magnetic field direction in each region, the magnitude and sign of the magnetic field emitted by each magnetic pole are obtained through inverse decoupling using the magnetic domain direction editing model, based on the known currents of the three coils. Solve for the magnetic field at the printing extrusion point. The magnetic domain orientation is edited to obtain the forward model. A magnetic field simulation model is built using COMSOL software. Multiple sets of current-magnetic field correspondences are obtained by scanning the current parameter matrix, thereby obtaining the inverse model. , , and A large amount of mapping data is used as the training set to train known... Solve The neural network inverse model, based on which the input control G code can be obtained from the known target magnetic domain editing parameters. Then, the required driving current for the three magnetic poles is obtained by adjusting the voltage of the current generator. Finally, the original G-code is modified using a G-code script re-editing algorithm to obtain control G-code with current instructions and UV light switching instructions for each step of the trajectory. (G1 XYZVWQEF U1) represents the material extrusion trajectory, or (G1 XYZV WQ EF U0) represents the idle stroke trajectory. V, W, and Q control drive voltage 1, drive voltage 2, and drive voltage 3, respectively. By measuring the resistance value of the magnetizing coil, the voltage value corresponding to the current is converted from the resistance value, thereby indirectly controlling the current input by controlling the voltage. E represents the material extrusion amount control parameter; F represents the printing speed control parameter; U0 and U1 represent the printing status. U0 is the idle stroke instruction, indicating that the nozzle moves but does not perform printing. U1 is the material extrusion and magnetic domain editing activation instruction, indicating that the current is a valid printing trajectory.

[0067] The G-code script re-editing algorithm employs a physical spatial gridding-based control strategy. Using the G28 zero-point as a fixed coordinate origin, the algorithm divides the entire printing platform into a fixed number of square grids, each with a unique row and column number. The model is imported into the Cura slicing software, and the required grid numbers are determined based on the model's shape. A post-processing script then sets specific voltage parameters according to deformation requirements and the grid numbers (location regions). As long as the grid size is small enough and the number of grids is sufficient, precise spatial partitioning and magnetic domain programming can be achieved during the printing process. This algorithm can be executed via the Cura slicing software's post-processing script, exporting integrated control G-code, such as (G1 XYZVWQEF U1), which includes spatial trajectory movement, magnetic field direction editing, and solidification.

[0068] Based on the preset regional magnetic domain direction setting, the G-code file exported by the slicing software is re-edited, and the corresponding current value is added in the form of G-code, so that the magnetic domain direction editing device generates a predetermined magnetic field direction, and the magnetic field direction during the printing process is edited, and the magnetic field strength at the extrusion needle tip is controlled within the range of 20mT-40mT.

[0069] See Figure 5 The figure is a schematic diagram of a magnetic field direction coordinate system transformation provided by an embodiment of the present invention. A three-dimensional rectangular coordinate system is established on the left side of the schematic diagram, and the three magnetic field components along the X, Y, and Z axes are clearly marked. , , These three components correspond to the magnetic fields generated by three orthogonally arranged magnetic coils. The direction of each magnetic field component is clearly indicated by arrows and coordinate axes in the diagram, providing a foundation for subsequent magnetic field vector synthesis. The central part of the diagram illustrates the magnetic field vector synthesis process, combining the magnetic field components along the three axes. , , Combined into a total magnetic field vector The diagram clearly shows the components of the total magnetic field in the X, Y, and Z directions. , , The diagram visually presents the total magnetic field in a Cartesian coordinate system. The right side of the diagram further analyzes the direction of the magnetic field using a spherical coordinate system. In the diagram, the center O of the sphere is the origin, and point P represents the point of application of the magnetic field, at a distance of... Indicates the distance and angle of the magnetic field's effect. This represents the direction angle of the magnetic field. The transformation from Cartesian coordinates to spherical coordinates was achieved through coordinate system transformation, demonstrating various coordinate system representation methods for describing the direction of the magnetic field and their transformation relationships.

[0070] The relationship between voltage and magnetic field strength can be expressed as:

[0071] ;

[0072] in, Indicates coil The current in Indicates input to the coil voltage, Indicates the resistance of the coil;

[0073] The magnetic flux density of a cylindrical stepped coil can be expressed as:

[0074] ;

[0075] in, Indicates coil The generated magnetic flux density Expressed as vacuum permeability, and It is the range of integration along the axial direction. It is the position along the axial direction. The radius of the coil at that location, It is a coil The number of turns. The direction of the external magnetic field is edited by adjusting the magnitude and direction of the current;

[0076] The vector sum of the three magnetizing coils at the extrusion point can be expressed as:

[0077] ;

[0078] In the formula, It is the total magnetic field at the extrusion point. These are the vectors of individual magnetic fields, and the components of each magnetic field can be expressed as:

[0079] ;

[0080] ;

[0081] ;

[0082] The direction of the total magnetic field can be represented by a unit vector:

[0083] ;

[0084] in, It is the magnitude of the total magnetic field, expressed as:

[0085] ;

[0086] Since 4D printers move according to a Cartesian coordinate system, but domain orientation editing requires a spherical coordinate system to more easily represent 360° orientation, the conversion from Cartesian to spherical coordinates can be expressed by the following formula:

[0087] Magnetic field direction vector Its modulus r is expressed as:

[0088] ;

[0089] ;

[0090] ;

[0091] in, It is the magnitude of the total magnetic field direction vector. It is the polar angle (the angle between the positive Z-axis and the direction of the magnetic field). It is the azimuth angle (the angle between the positive x-axis and the projection of the magnetic field direction onto the xy plane).

[0092] By adjusting the current of each coil , , It can precisely control the direction and intensity of the total magnetic field.

[0093] See Figure 3 The figure is a schematic diagram of a domain direction editing device provided by an embodiment of the present invention. The domain direction editing device provided by the present invention mainly consists of the following parts:

[0094] Extrusion syringe: Located at the top center of the device, it has a cylindrical structure and is used to hold the material to be extruded or processed.

[0095] Connecting plate: Located below the extrusion syringe, it is fixedly connected to the extrusion syringe by fasteners, and serves to connect and support the components above (such as the extrusion syringe, UV irradiation head, etc.).

[0096] UV irradiation head: Installed on one side of the connecting plate at an angle, it is used to emit ultraviolet light to a specific area below to meet the curing or other light processing requirements that the device may need during the magnetic domain editing process.

[0097] Magnetic coils: Symmetrically distributed on both sides below the connecting plate, each coil is a ring structure, and its function is to generate a magnetic field to achieve the editing and control of magnetic domain direction.

[0098] Conical outer shell: It covers the outside of the magnetizing coil and is cone-shaped. It not only protects the internal magnetizing coil and other components, but may also play a role in guiding the distribution of the magnetic field.

[0099] Extrusion needle tip: Located at the bottom center of the device, it is connected to the extrusion syringe and is used to precisely extrude the material in the extrusion syringe to a designated position for subsequent magnetic domain editing operations.

[0100] The aforementioned components work together to form the magnetic domain orientation editing device, enabling precise and effective magnetic domain orientation editing.

[0101] S104: Prepare a UV-curable soft material containing magnetic particles and load it into the printing syringe of a 4D printer.

[0102] In this embodiment of the invention, permanent magnet material powder and UV-curable polymer matrix are selected; the permanent magnet material powder and UV-curable polymer matrix are mixed and stirred evenly according to a predetermined mass ratio; the mixed material is subjected to vacuum treatment to remove air bubbles; the mixed material after removing air bubbles is allowed to stand for a predetermined time to obtain a uniform and printable UV-curable soft material containing magnetic particles.

[0103] Specifically, a material containing magnetic particles is prepared, and the material is mixed evenly by stirring, vacuumed, and left to stand for 4 minutes to remove air. Finally, the material is loaded into a printing syringe. The mixed material can be a mixture of powdered neodymium iron boron and UV-curable silicone mixed in a certain proportion and stirred for 5 minutes.

[0104] Experiments have shown that a ratio of NdFeB powder to UV-curable silicone lower than 4:6 results in insufficient driving force of the magnetic material, while a ratio higher than 5:5 leads to insufficient elasticity, decreased elongation, and easy breakage. Therefore, in this embodiment of the invention, powdered NdFeB and UV-curable silicone are mixed in a ratio of 4:6 to 5:5 to prepare a UV-curable flexible material, resulting in good elasticity.

[0105] It should be noted that the settling time and mixing time after vacuuming in this invention are only examples. The specific values ​​are set according to the preparation requirements in actual applications. This invention does not impose specific limitations on the embodiments.

[0106] In one implementation of this invention, an integrated rotatable printhead design is adopted, and the magnetic domain direction editing device is upgraded in hardware. A 360° rotatable printhead module that coaxially integrates the generating magnetic coil and the UV curing head is used to replace the original fixed multi-coil synthesized magnetic field system. The magnetic field direction is determined by directly controlling the physical rotation angle of the integrated printhead, and then the magnetic field action and synchronous UV curing are triggered. This simplifies the complex multi-channel current control and magnetic field synthesis algorithm, making the system control more direct and stable, which is beneficial to the miniaturization and cost control of the printhead.

[0107] S105: Set printing process parameters.

[0108] In this embodiment of the invention, the printing process parameters are synergistically optimized based on the rheological properties of the UV-curable soft material and the response characteristics of the magnetic particles. The printing process parameters include printing speed, extrusion flow rate, and the range of magnetic field strength at the extrusion point.

[0109] Specifically, edit the printing process parameters, selecting different printing speeds and extrusion flow rates based on the viscosity of the raw material. Set the printing speed to 3mm / s, the extrusion flow rate to 180%, the UV curing power to 1W, and the distance from the material extrusion point to 30mm. This ensures the layer height and width of the extruded material, prevents the material from curing at the unextruded area of ​​the needle tip, and forms a non-flowing, semi-cured, flexible material. This also prevents magnetic particles from being attracted to the coil core, thereby improving the printing success rate.

[0110] It should be noted that the printing process parameters set in this invention are only examples, and the specific values ​​should be set according to the needs of actual applications. This invention does not impose any specific limitations.

[0111] S106: The printing process is executed according to the control G code. During material extrusion, multiple magnetic fields are coupled at the extrusion point to synthesize a three-dimensional magnetic field in a preset direction, so that the magnetic particles are oriented along the magnetic field direction to form target magnetic domains. After a preset delay time, the UV curing material is turned on to lock the magnetic domain direction, so as to obtain a soft 4D printed product with a regionalized magnetic domain direction.

[0112] In this embodiment of the invention, multiple magnetic fields are generated by three magnetizing coils. These three coils are randomly arranged around the material extrusion point at a uniform 120° angle. The magnetic field generation directions of the three coils are orthogonal to each other in three-dimensional space, and the ends of the magnetic cores of each coil maintain a predetermined working distance from the extrusion point. The UV irradiation head is activated with a predetermined delay after the material extrusion begins. Based on the curing characteristics of the UV-curable soft material, the wavelength of the UV light, the irradiation diameter, and the distance between the UV irradiation head and the material extrusion point are adaptively set.

[0113] See Table 1, which records the experimental data on the directional control accuracy of the coupled magnetic field generated by the three coils. It visually presents the comparison between the target and measured values ​​of the magnetic field parameters. The table includes the magnetic flux density of the target magnetic field. Polar angle Azimuth The corresponding input current values ​​for the three coils ( , , The data, along with the measured magnetic field parameters, shows that the measured values ​​deviate very little from the target values, confirming the accuracy of controlling the magnetic field direction through coil current in 4D printing technology and providing reliable experimental support for spatial regional magnetic domain editing.

[0114]

[0115] Table 1. Experimental data on the directional control accuracy of the coupled magnetic field generated by the three coils.

[0116] Specifically, this invention employs an ink extrusion printing method combined with UV curing for molding. The principle of ink extrusion printing is to apply pressure to the ink inside the print head, forcing it out of the fine nozzles and spraying it onto a medium such as paper, thereby forming patterns or text. As the material is extruded from the nozzles, it gradually solidifies under UV light, ultimately forming a three-dimensional model.

[0117] Adjusting the on / off timing and irradiation distance of the UV curing head is crucial. If the UV light is not synchronized with the extrusion nozzle during printing, the printed material may cure at the nozzle tip; conversely, if the curing effect is too weak, magnetic particles may be attracted to the coil core. The UV LED control box drives the UV light emitted from the UV irradiation head to cure the extruded material. The UV irradiation head's on-time is delayed by 0.2 seconds relative to the extrusion start time. It accurately outputs the required magnetic field through three magnetic fields orthogonal to the extrusion point (the coil core ends are all 5mm from the extrusion point end), enabling precise magnetic editing and real-time curing during printing. This allows for regional spatial angular magnetic field editing, preventing changes in magnetic domain orientation within the material. It initiates regional magnetic domain orientation editing printing, enabling 4D printing of flexible material products with regional magnetic domain orientation, allowing for complex deformation of soft materials.

[0118] In this embodiment of the invention, the delay time between the UV irradiation head opening time and the extrusion start time is set to 0.2 seconds. See also Figure 6 , Figure 6 This is a comparison chart of printing effects with different delay times provided in an embodiment of the present invention. When the delay time is 0.5s or longer, it will lead to untimely curing. Since it is a real-time magnetic editing process, when the pole head that continuously outputs the magnetic field crosses the printed but not fully cured magnetic material, it will be attracted away by the pole head, resulting in poor printing effect, including magnetic domain angle, dimensional accuracy, roughness and other properties.

[0119] The magnetic field generator consists of a cylindrical stepped coil wound around a conical shaft, with the smallest diameter cylinder near the tip of the shaft. A total of 510 turns of 0.6mm diameter copper wire are wound around each of the three conical shafts. Current is controlled using an Arduino. The UV irradiation head uses light with a wavelength of 365nm and an irradiation diameter of 10mm. The UV LED control box is a 20W unit.

[0120] It should be noted that the values ​​set for the magnetic field generating device in this embodiment of the invention are merely examples, and the specific values ​​should be set according to the needs of actual applications. This embodiment of the invention does not impose any specific limitations.

[0121] See Figure 4 , Figure 4 This is a schematic diagram of a 4D printing process provided in an embodiment of the present invention. Figure 4 The device comprises a magnetic domain orientation editing generator, a curing range, a printing platform, a magnetic field direction, and cured material. In the initial printing stage, the printing platform holds the material to be printed, and the magnetic domain orientation editing generator is in its initial position. Regional magnetic domain orientation editing printing begins. The extrusion drive motor extrudes the raw material mixed with magnetic particles from the needle tip. When the material is in a liquid, uncured state, three magnetizing coils arranged at a 120° angle below the coil connecting plate are instantaneously energized according to a command. This creates a three-dimensional magnetic field with a preset direction below the needle tip, orienting the magnetic particles. This process corresponds to the stage in the diagram where the magnetic domain orientation editing generator applies a magnetic field to the printing material. Simultaneously, a UV irradiation head fixed to the coil connecting plate and the connecting plate is instantly activated, irradiating the material and rapidly curing it. This fixes the magnetic domain orientation of the magnetic particles in the material, giving the printed robot a magnetic quality. This corresponds to the curing range shown in the diagram and the transformation of the material from uncured to cured. As the printing process progresses, under the influence of the magnetic field direction, the magnetic domain orientation editing generator acts on the printing material, causing the material within the curing range to gradually solidify into a cured material. Subsequently, the printing platform descends a certain distance to provide space for the printing of the next layer of material. The magnetic domain direction editing device then performs the aforementioned magnetic domain editing and curing treatment on the new printing material under the action of the corresponding magnetic field direction. This process is repeated to achieve the 4D printing process of printing and curing layer by layer.

[0122] In one implementation of this invention, adaptive path planning based on machine learning algorithms can be used. By training a neural network model, it learns the complex mapping relationship between "printed structure - magnetic domain pattern - final deformation". The advantage of this approach is that the user only needs to input the target deformation state, and the model can automatically generate the optimal regionalized printing path and the corresponding real-time magnetic field control instructions, thereby realizing the intelligentization and automation from deformation requirements to manufacturing instructions, and greatly improving the design and printing efficiency of complex structures.

[0123] This invention discloses a 4D printing method for soft materials with regionalized magnetic domain orientation, enabling editing of magnetic domain orientations in various spatial directions without the need for post-processing. The magnetic domain orientation editing method of this invention is unaffected by the printing path; the magnitude and direction of the vector at the extrusion point are absolute values ​​in space. This invention features a modular design and is detachable, facilitating disassembly and assembly according to different printing requirements. A controllable delay exists between the application of the magnetic field and the activation of the UV curing light to lock the magnetic domain orientation. This invention achieves three-dimensional spatial regional editing of the magnetic domain orientation within soft materials. Compared to traditional processes that can only achieve two-dimensional bending (planar angles), this invention significantly improves the design freedom and complex motion control of 4D printed products, enabling three-degree-of-freedom shape bending (spatial shape), providing reliable technical support for the integrated manufacturing of complex driven soft robots.

[0124] Based on the methods provided in the above embodiments, this invention also provides a 4D printing apparatus for soft materials with configurable magnetic domain orientation. The following description of the 4D printing apparatus for soft materials with configurable magnetic domain orientation is in conjunction with the accompanying drawings.

[0125] See Figure 7 The figure is a schematic diagram of the structure of a soft material 4D printing device with regionalized magnetic domain orientation provided by an embodiment of the present invention.

[0126] The soft material 4D printing apparatus 700 with regionalized magnetic domain orientation provided in this embodiment of the invention includes: a modeling unit 701, a planning unit 702, a reprogramming unit 703, a preparation unit 704, a setting unit 705, and a printing unit 706.

[0127] Modeling unit 701 is used to create a partitioned 3D model of the object to be printed using 3D modeling software;

[0128] Planning unit 702 is used to import the partitioned 3D model into slicing software for regional printing path planning and generate raw G-code.

[0129] The reprogramming unit 703 is used to obtain the driving parameters of multiple magnetic poles by reverse decoupling through the magnetic field model based on the preset regional magnetic domain direction requirements, and to re-edit the original G code, integrating the driving parameter instructions and ultraviolet switch instructions into the original G code to obtain the control G code;

[0130] Preparation unit 704 is used to prepare UV-curable soft material containing magnetic particles and load it into the printing syringe of a 4D printer.

[0131] Setting unit 705 is used to set printing process parameters;

[0132] The printing unit 706 is used to execute the printing process according to the control G code. During material extrusion, multiple magnetic fields are coupled at the extrusion point to synthesize a three-dimensional magnetic field in a preset direction, so that the magnetic particles are oriented along the magnetic field direction to form target magnetic domains. After a preset delay time, the UV curing material is turned on to lock the magnetic domain direction, so as to obtain a soft 4D printed product with a regionalized magnetic domain direction.

[0133] In one possible implementation, reprogramming unit 703 is specifically used for:

[0134] A control strategy based on physical space gridding is adopted to divide the printing platform into multiple grid cells;

[0135] Based on the projection of the partitioned 3D model onto the printing platform and the correspondence between multiple grid cells, and combined with the preset magnetic domain direction requirements for each region, specific magnetic field control parameters are set for each grid cell covered by the partitioned 3D model.

[0136] The magnetic field control parameters are converted into corresponding voltage control commands through a post-processing script.

[0137] The voltage control command and the ultraviolet switch command are integrated into the original G code to obtain the control G code.

[0138] In one possible implementation, reprogramming unit 703 is specifically used for:

[0139] Define the direction vector of the target's total magnetic field in spherical coordinates;

[0140] Convert the direction vector into magnetic field components in a Cartesian coordinate system;

[0141] Based on the spatial position and magnetic field strength model of each magnetic pole, the required driving current value of each magnetic pole is solved in reverse according to the magnetic field components.

[0142] The drive current value is converted into the corresponding voltage control command, thereby obtaining the drive parameters for multiple magnetic poles.

[0143] In one possible implementation, multiple magnetic fields are generated by three magnetizing coils, which are arranged around the material extrusion point at a uniform angle of 120°. The magnetic field generation directions of the three magnetizing coils are orthogonal to each other in three-dimensional space, and the end of the magnetic core of each magnetizing coil maintains a predetermined working distance from the extrusion point.

[0144] In one possible implementation, the preparation unit 704 has features for:

[0145] Select permanent magnet material powder and UV-curable polymer matrix;

[0146] The permanent magnet material powder and the UV-cured polymer matrix are mixed and stirred evenly according to a predetermined mass ratio;

[0147] The mixed materials are subjected to vacuum treatment to remove air bubbles;

[0148] After removing air bubbles, the mixed material is left to stand for a predetermined time to obtain a uniform and printable UV-curable soft material containing magnetic particles.

[0149] In one possible implementation, the printing unit 706 has features for:

[0150] The UV irradiation head is activated after a predetermined delay following the start of material extrusion.

[0151] Based on the curing characteristics of UV-curable soft materials, the wavelength of UV light, the irradiation diameter, and the distance between the UV irradiation head and the material extrusion point are adapted and set.

[0152] In one possible implementation, the setting unit 705 has the following features:

[0153] The printing process parameters are synergistically optimized based on the rheological properties of the UV-curable soft material and the response characteristics of the magnetic particles. These parameters include printing speed, extrusion flow rate, and the range of magnetic field strength at the extrusion point.

[0154] Since the soft material 4D printing apparatus 700 with configurable magnetic domain orientation is the same apparatus as the soft material 4D printing method with configurable magnetic domain orientation provided in the above method embodiments, the specific implementation of each unit of the soft material 4D printing apparatus 700 with configurable magnetic domain orientation is based on the same concept as in the above method embodiments. Therefore, for the specific implementation of each unit of the soft material 4D printing apparatus 700 with configurable magnetic domain orientation, please refer to the description of the soft material 4D printing method with configurable magnetic domain orientation in the above method embodiments, and will not be repeated here.

[0155] This invention also provides a 4D printing device for soft materials with zonal magnetic domain orientation, the device comprising: a processor and a memory;

[0156] The memory is used to store instructions;

[0157] The processor is configured to execute the instructions in the memory to perform the soft material 4D printing method with zonal magnetic domain orientation mentioned in the above embodiments.

[0158] It should be noted that the hardware structure of the soft material 4D printing equipment with regionalizable magnetic domain orientation provided in the embodiments of the present invention can be as follows: Figure 8 The structure shown, Figure 8This is a schematic diagram of the structure of a soft material 4D printing device with regionalized magnetic domain orientation provided in an embodiment of the present invention.

[0159] Please see Figure 8 As shown, device 800 includes: a processor 810, a communication interface 820, and a memory 830. The number of processors 810 in device 800 can be one or more. Figure 8 Taking a processor as an example, in this embodiment of the invention, the processor 810, communication interface 820, and memory 830 can be connected via a bus system or other means. Figure 8 Taking the connection between China and Israel via the 840 bus system as an example.

[0160] Processor 810 may be a central processing unit (CPU), a network processor (NP), or a combination of a CPU and an NP. Processor 810 may further include hardware chips. These hardware chips may be application-specific integrated circuits (ASICs), programmable logic devices (PLDs), or combinations thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), generic array logic (GAL), or any combination thereof.

[0161] The memory 830 may include volatile memory, such as random-access memory (RAM); the memory 830 may also include non-volatile memory, such as flash memory, hard disk drive (HDD) or solid-state drive (SSD); the memory 830 may also include a combination of the above types of memory.

[0162] Optionally, the memory 830 stores an operating system and programs, executable modules, or data structures, or subsets thereof, or extended sets thereof. The programs may include various operation instructions for implementing various operations. The operating system may include various system programs for implementing various basic business processes and handling hardware-based tasks. The processor 810 can read the programs in the memory 830 to implement the soft material 4D printing method with regionalized magnetic domain orientation provided in this embodiment of the invention.

[0163] The bus system 840 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus system 840 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 8 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0164] This invention also provides a computer-readable storage medium including instructions that, when executed on a computer, cause the computer to perform the soft material 4D printing method with zonal magnetic domain orientation mentioned in the above embodiments.

[0165] This invention also provides a computer program product containing instructions that, when run on a computer, cause the computer to execute the soft material 4D printing method with zonal magnetic domain orientation mentioned in the above embodiments.

[0166] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A method for 4D printing soft materials with regionalizable magnetic domain orientation, characterized in that, The method includes: Create a partitioned 3D model of the object to be printed using 3D modeling software; The partitioned 3D model is imported into slicing software for regional printing path planning, generating the original G-code. Based on the preset regional magnetic domain direction requirements, the driving parameters of multiple magnetic poles are obtained by reverse decoupling through the magnetic field model, and the original G code is re-edited to integrate the driving parameter instructions and ultraviolet switch instructions into the original G code to obtain the control G code. The re-editing of the original G-code, integrating the drive parameter instructions and ultraviolet switch instructions into the original G-code to obtain control G-code, includes: employing a physical space gridding-based control strategy to divide the printing platform into multiple grid cells; based on the correspondence between the projection of the partitioned 3D model on the printing platform and the multiple grid cells, and combined with the preset magnetic domain direction requirements for each region, setting specific magnetic field control parameters for each grid cell covered by the partitioned 3D model; converting the magnetic field control parameters into corresponding voltage control instructions through a post-processing script; and integrating the voltage control instructions and ultraviolet switch instructions together into the original G-code to obtain the control G-code. The method of obtaining the driving parameters of multiple magnetic poles by inverse decoupling from the magnetic field model based on the preset regional magnetic domain direction requirements includes: setting the direction vector of the target total magnetic field in the spherical coordinate system; converting the direction vector into magnetic field components in the rectangular coordinate system; based on the spatial position and magnetic field strength model of each magnetic pole, inversely solving the driving current value required for each magnetic pole according to the magnetic field components; and converting the driving current value into the corresponding voltage control command, thereby obtaining the driving parameters of the multiple magnetic poles. Prepare a UV-curable soft material containing magnetic particles and load it into the printing syringe of a 4D printer; Set printing process parameters; The printing process is executed according to the control G code. During material extrusion, multiple magnetic fields are coupled at the extrusion point to synthesize a three-dimensional magnetic field in a preset direction, causing magnetic particles to align in the direction of the magnetic field to form target magnetic domains. After a preset delay time, the UV curing material is turned on to lock the magnetic domain direction, thereby obtaining a soft 4D printed product with a regionalized magnetic domain direction.

2. The method according to claim 1, characterized in that, The multiple magnetic fields are generated by three magnetizing coils, which are arranged around the material extrusion point at a uniform angle of 120°. The magnetic field generation directions of the three magnetizing coils are orthogonal to each other in three-dimensional space, and the end of the magnetic core of each magnetizing coil maintains a predetermined working distance from the extrusion point.

3. The method according to claim 1, characterized in that, The preparation of the UV-curable soft material containing magnetic particles includes: Select permanent magnet material powder and UV-curable polymer matrix; The permanent magnet material powder and the UV-cured polymer matrix are mixed and stirred evenly according to a predetermined mass ratio; The mixed materials are subjected to vacuum treatment to remove air bubbles; After removing air bubbles, the mixed material is left to stand for a predetermined time to obtain a uniform and printable UV-curable soft material containing magnetic particles.

4. The method according to claim 1, characterized in that, The step of activating the UV curing of the material after a preset delay time includes: The UV irradiation head is activated after a predetermined delay following the start of material extrusion. Based on the curing characteristics of the UV-curable soft material, the wavelength of the UV light, the irradiation diameter, and the distance between the UV irradiation head and the material extrusion point are adapted and set.

5. The method according to claim 1, characterized in that, The setting of printing process parameters includes: The printing process parameters are synergistically optimized based on the rheological properties of the UV-curable soft material and the response characteristics of the magnetic particles. The printing process parameters include printing speed, extrusion flow rate, and the range of magnetic field strength at the extrusion point.

6. A 4D printing apparatus for soft materials with regionalizable magnetic domain orientation, characterized in that, The device includes: Modeling unit, used to create a partitioned 3D model of the object to be printed using 3D modeling software; The planning unit is used to import the partitioned 3D model into slicing software for regional printing path planning and generate the original G-code. The reprogramming unit is used to obtain the driving parameters of multiple magnetic poles by reverse decoupling through the magnetic field model based on the preset regional magnetic domain direction requirements, and to re-edit the original G code, integrating the driving parameter instructions and ultraviolet switch instructions into the original G code to obtain the control G code; The reprogramming unit is specifically used to set the direction vector of the target total magnetic field in spherical coordinates; convert the direction vector into magnetic field components in rectangular coordinates; based on the spatial position and magnetic field strength model of each magnetic pole, solve the required driving current value of each magnetic pole in reverse according to the magnetic field components; convert the driving current value into the corresponding voltage control command, thereby obtaining the driving parameters of the multiple magnetic poles; adopt a control strategy based on physical space gridding to divide the printing platform into multiple grid units; according to the projection of the partitioned 3D model on the printing platform and the correspondence between the multiple grid units, and combined with the preset magnetic domain direction requirements for each region, set specific magnetic field control parameters for each grid unit covered by the partitioned 3D model; convert the magnetic field control parameters into corresponding voltage control commands through a post-processing script; integrate the voltage control commands and ultraviolet switch commands into the original G-code to obtain the control G-code; The preparation unit is used to prepare UV-cured soft materials containing magnetic particles and load them into the printing syringe of a 4D printer. The settings unit is used to set printing process parameters; The printing unit is used to execute the printing process according to the control G code. During material extrusion, multiple magnetic fields are coupled at the extrusion point to synthesize a three-dimensional magnetic field in a preset direction, so that magnetic particles are oriented along the magnetic field direction to form target magnetic domains. After a preset delay time, the UV curing material is turned on to lock the magnetic domain direction, so as to obtain a soft 4D printed product with a regionalized magnetic domain direction.

7. A 4D printing device for soft materials with regionalizable magnetic domain orientation, characterized in that, The device includes: a processor and a memory; The memory is used to store instructions; The processor is configured to execute the instructions in the memory to perform the method according to any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, Including instructions that, when run on a computer, cause the computer to perform the method described in any one of claims 1-5 above.

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