Melt electric writing curve printing device and method based on translation-rotation cooperative motion

Abstract

The invention belongs to the technical field of melt electric-writing printing, and relates to a melt electric-writing curve printing device and method based on translation-rotation cooperative motion, and the device comprises a spray head, a collecting plate, a high-pressure generator, a composite motion platform, a visual monitoring unit and a control system; the composite motion platform is used for bearing the collecting plate, the composite motion platform is jointly driven by a translation module and a rotating module arranged below the translation module, the translation module is used for driving the composite motion platform to do plane translation motion, and the rotating module is used for driving the translation module and the collecting plate to jointly rotate around a vertical fixed axis; the method comprises the steps that S1, printing process parameters are determined and initialized; s2, path planning and motion parameter preprocessing; and S3, cooperative motion printing and real-time feedback control are carried out. The device disclosed by the invention fundamentally solves the problems of precision and consistency in electric writing and printing of a melt with a complex curve structure; according to the method, the printing accuracy is improved.

Description

Technical Field

[0001] This invention belongs to the field of melt electro-writing printing technology, and relates to a melt electro-writing curve printing device and method based on translational-rotational coordinated motion. Background Technology

[0002] Melt electrowriting is a solvent-free, high-resolution additive manufacturing method. It involves applying an electric field to a molten polymer under a high electric field, causing the melt to form a stable jet, which is then deposited on a collection platform to construct fine fiber structures. This technology offers advantages such as a wide range of applicable materials, controllable fiber dimensions, and strong designability of microstructures. It is applicable to various thermoplastic polymer systems, including polycaprolactone, polylactic acid, and thermoplastic polyurethane. The resulting fiber diameter can typically be controlled within the range of 1–50 μm, and it has shown promising application prospects in fields such as tissue engineering scaffolds, flexible electronic devices, and micro / nano sensor manufacturing.

[0003] In the actual printing process of melt writing, due to the relative motion between the printhead and the collection platform, the jet will deviate from the vertical direction under the dragging effect of the platform, resulting in the actual landing point of the jet not coinciding with the projection position of the printhead on the collection platform, thus producing a jet lag phenomenon.

[0004] The jet hysteresis phenomenon mainly affects the printing process in two ways: First, when the printing path changes direction, the actual deposition trajectory of the jet may deviate from the movement trajectory of the nozzle, resulting in the fiber pattern being inconsistent with the preset path, thereby reducing printing accuracy; Second, under the condition that the extrusion flow rate remains constant, the fluctuation of the jet hysteresis length will cause the melt deposition rate to change. According to the mass conservation relationship, the fiber diameter will change accordingly, thus affecting the consistency of the fiber diameter.

[0005] Under linear printing conditions, the impact of jet hysteresis on print quality is usually limited to local areas, such as trajectory deviation at path corners or local fiber diameter unevenness caused by occasional fluctuations in jet hysteresis length. The overall structural accuracy and fiber consistency can still be kept within a relatively controllable range. However, during curved printing, due to the continuous change in printing direction, the stretching state of the jet is constantly in a dynamic adjustment process, causing the jet hysteresis length to fluctuate continuously throughout the printing process. This makes the printing trajectory deviation and fiber diameter unevenness exhibit global characteristics, significantly reducing the overall accuracy and stability of the formed structure.

[0006] To address the aforementioned issues, existing technologies have proposed various improvement solutions, but they still have significant limitations and cannot fundamentally solve the instability problem caused by jet hysteresis during curve printing.

[0007] Reference 1 (Designing with Circular Arc Toolpaths to Increase the Complexity of Melt Electrowriting. [J]. Advanced Materials Technologies, 2022, 7(10).) proposes to improve the accuracy of low-layer curve printing by adjusting process parameters to make the jet hysteresis length as close to zero as possible, so that the jet is printed approximately perpendicular to the collection platform. At the same time, during multi-layer printing, when the path between layers is offset, an empirical compensation amount is introduced into each layer's printing path to correct the error caused by tilting. However, the critical state of jet hysteresis approaching zero is extremely sensitive to external disturbances. This method usually requires multiple trials to obtain stable results, has a narrow process window, and limited repeatability and practicality.

[0008] Reference 2 (Fiber Bridging during Melt Electrowriting of Poly(ε-Caprolactone) and the Influence of Fiber Diameter and Wall Height [J]. Macromolecular Materials and Engineering, 2021, 306(3)) proposes setting a short pause at the path turning point to allow the jet to stabilize before continuing printing. However, this method is only suitable for scenarios with small-angle turns on straight paths (curvature ≤ 0.1 mm). -1 Furthermore, the dwell time at the turning point is prone to cause local fiber accumulation, which disrupts the structural continuity. At the same time, the dwell time is difficult to control precisely, which can easily induce abrupt changes in fiber diameter.

[0009] Reference 3 (3D Printing of High-Resolution Multi-Layer Scaffolds With Melt Electrowriting. [J]. Advanced Materials Technologies, 2025, 10, 2402029) proposes an Extended Path Algorithm (EPA), which pre-compensates for jet hysteresis by extending the nozzle's motion path by a preset angle (e.g., 90°, 135°) before the turning node, thereby reducing trajectory offset at edges and turning points. However, this method is mainly applicable to turning scenarios with discrete fixed angles and lacks adaptability to continuous curves with varying curvature.

[0010] Patent CN119910907A discloses an online monitoring method for jet hysteresis in melt electro-writing curve printing and a method to improve the accuracy of melt electro-writing curve printing. This method monitors the jet hysteresis length online and dynamically adjusts the printing path, employing a path compensation strategy to correct jet landing point deviations. However, within this technical framework, the jet still needs to change direction along the path. Due to the existence of jet inertia, the jet projection direction and the actual fiber deposition trajectory are difficult to maintain a constant tangent relationship, and the jet hysteresis length is also difficult to keep constant, affecting the path compensation effect and the uniformity of fiber diameter.

[0011] In summary, existing technologies mainly compensate for jet hysteresis through parameter adjustment, path correction, or local dwell, but none of them fundamentally constrain the jet attitude from the perspective of motion control mechanism, making it difficult to simultaneously ensure the accuracy of the trajectory of curve printing and the consistency of fiber diameter.

[0012] Therefore, it is of great significance to study a melt electro-writing curve printing device and method based on translational-rotational coordinated motion to solve the problems existing in the prior art. Summary of the Invention

[0013] The purpose of this invention is to solve the problems existing in the prior art and to provide a melt electro-writing curve printing device and method based on translational-rotational coordinated motion.

[0014] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0015] A melt electro-writing curve printing device based on translational-rotational coordinated motion includes a nozzle, a collection plate, and a high-voltage generator that provides voltage to the nozzle, as well as a composite motion platform, a vision monitoring unit, and a control system;

[0016] The composite motion platform is used to support the collection plate. The composite motion platform is driven by a translation module and a rotating module located below it. The translation module is used to drive the composite motion platform to perform planar translational motion, and the rotating module is used to drive the translation module and the collection plate to rotate together around a vertical fixed axis.

[0017] The visual monitoring unit is used to acquire the hysteresis length of the jet between the nozzle and the collection plate in real time;

[0018] The control system is electrically connected to the translation module, rotation module, vision monitoring unit, and high-voltage generator;

[0019] The control system is configured to: control the translation module and the rotation module to move in coordination according to the preset motion control information; receive the jet hysteresis length fed back by the visual monitoring unit and compare it with the set value; and dynamically adjust the output voltage of the high voltage generator according to the comparison result.

[0020] The core principle of this invention lies in actively eliminating the inertial effect during the printing process from the motion control level by enabling the collection platform to perform a combined translational and rotational motion, thus making the jet tend towards "quasi-static" stability in space and fundamentally solving the problems of trajectory distortion and fiber unevenness in curved printing. Specifically, the device is composed of a translational module and a rotational module working together. The translational module is responsible for driving the collection plate to translate with high precision along a preset curved trajectory, realizing the macroscopic positioning of the fiber deposition points and laying the geometric foundation of the structure. The rotational module, on the other hand, adjusts the rotation according to the real-time curvature of the path. With translational velocity According to the formula The required compensation angular velocity is dynamically calculated, driving the entire translational module and the collection plate to rotate synchronously around the vertical axis, thus eliminating inertial effects. The two modules work together to produce a key effect: observed in a static coordinate system fixed to the nozzle, the spatial attitude of the jet remains stable, the jet landing point remains unchanged, and the translational module performs translational motion relative to the jet landing point (rather than the nozzle projection), thus fundamentally eliminating trajectory deviation. Simultaneously, the stable jet state, combined with other closed-loop control methods, effectively suppresses hysteresis length fluctuations and the resulting fiber diameter unevenness, ultimately achieving high-precision, high-consistency printing of complex curves.

[0021] As a preferred technical solution:

[0022] As described above, a melt electro-writing curve printing device based on translational-rotational coordinated motion uses a servo motor in the translational module to achieve translation in the X, Y, and Z coordinate axes.

[0023] The rotating module uses a servo motor to achieve R-axis rotation.

[0024] As described above, a melt electro-writing curve printing device based on translational-rotational coordinated motion has a collection plate made of aluminum alloy square plate with a side length of 20 mm and a thickness of 5 mm. The collection plate is grounded by connecting wires.

[0025] The distance between the nozzle and the collection plate is 3 mm.

[0026] As described above, the melt electro-writing curve printing device based on translational-rotational coordinated motion has a high-speed industrial camera as its visual monitoring unit, with a resolution of 1280×720 pixels and a maximum frame rate of 5000 fps, ensuring that the morphology of the jet can be clearly captured.

[0027] The visual monitoring unit is responsible for observing the jet status in real time and providing feedback signals to the control system.

[0028] Installation configuration: The industrial camera is fixed by an adjustable bracket. Its lens optical axis is perpendicular to the vertical plane where the jet is located. The horizontal distance between the lens and the nozzle tip is 10~15 cm. The installation height and angle are adjusted to ensure that the nozzle tip, the entire length of the jet and the deposition point of the collection plate are clearly imaged in the center of the field of view at the same time.

[0029] Light source: Equipped with a white LED light source, the jet is illuminated from behind to form a high-contrast backlight or sidelight image, which facilitates subsequent image processing.

[0030] The present invention also provides a method for printing melt electro-writing profiles using the apparatus described in any of the preceding claims, comprising the following steps:

[0031] S1: Determining and initializing printing process parameters;

[0032] S2: Path planning and motion parameter preprocessing;

[0033] S21: Perform equal-arc-length discrete sampling on the preset continuous printed curve trajectory to obtain a series of discrete path points. The arc length between adjacent points is ;

[0034] S22: At the starting point of the discrete path Previously, a section of length was added. A straight path, which coincides with a preset continuous printing curve trajectory. Point tangency ensures a stable transition during the jet initiation phase;

[0035] S23: Based on discrete path points The unit tangent vector at each point is calculated using the central difference method. curvature and the unit tangent vector at that point With the initial tangent vector (i.e., the first waypoint) The angle between the directions of the unit tangent vector at the location ;

[0036] S24: Based on the preset translational linear velocity of the composite motion platform and the curvature of each discrete path point According to the formula Calculate the angular velocity required for the rotating module at each corresponding point. angular velocity Adjustment range: 0.1~25 rad / s;

[0037] S3: Cooperative motion printing and real-time feedback control;

[0038] S31: Set the high-voltage generator voltage to... After observing the stable deposition of the jet, the composite motion platform was controlled to move along a path sequence. Motion, in which the translational module moves at a speed The drive platform translates while the rotating module moves to each point. At that time, with angular velocity Drive the composite motion platform to rotate to the angle ;

[0039] S32: During the printing process, the vision monitoring unit captures images in real time, including the needle, jet, and collection plate. The control system then calculates the actual hysteresis length of the jet. ;

[0040] The control system incorporates an image processing algorithm that analyzes each frame of image captured by the industrial camera in real time. The algorithm first performs binarization and edge enhancement, then scans and identifies the nozzle exit position and the deposition points of the jet on the collection plate, calculating the pixel distance between the two points. Finally, based on a pre-calibrated pixel-to-actual-size ratio, it calculates the actual hysteresis length of the jet in real time. ;

[0041] S33: Real-time comparison by the control system With the jet hysteresis length setting value ,like > If the feedback control increases the output voltage, the high-voltage generator will increase it; otherwise, it will decrease it to maintain the output voltage. Constant to nearby.

[0042] As a preferred technical solution:

[0043] As described above, the printing process parameters in step S1 include: a stable extrusion flow rate Q of the polymer melt, which is 0.05~0.5 μL / min; and the target fiber diameter for printing. The theoretical platform translational linear velocity V is 5~50 μm; the voltage setpoint of the high-voltage generator is 3~15 mm / s. The voltage is 3.0~4.5 kV; the jet hysteresis length setting value is... The thickness is 0.1~2mm.

[0044] In step S21 of the method described above, It is 0.1 mm.

[0045] In step S22 of the method described above, It is 10 cm.

[0046] In step S23 of the method described above, , and The calculation formula is as follows:

[0047] ;

[0048] = , where (·) represents the vector dot product;

[0049] .

[0050] As described above, in step S33, the control system uses a closed-loop control method to regulate the voltage of the high-voltage generator. The closed-loop control method is proportional-integral-derivative control or model predictive control.

[0051] The control system is the core of the entire device, enabling logical calculations, motion coordination, and real-time control.

[0052] The control system hardware consists of a computer, servo drivers, and a high-voltage generator interface module.

[0053] Path parsing and motion planning: Read in the preprocessed path file and generate position commands for the translation module (X, Y, Z axes) and angle / angular velocity commands for the rotation module (R axis);

[0054] Multi-axis collaborative control: Motion commands are issued to the translation and rotation modules in a highly synchronized manner to ensure the platform moves along the curved trajectory. At the same time, it also rotates to the point. horn;

[0055] Real-time feedback control: Receives data measured by the visual monitoring unit. , compared with the preset jet hysteresis length setting value By comparing the results, the voltage is adjusted in real time based on the control algorithm to stabilize the jet hysteresis length.

[0056] Beneficial effects:

[0057] (1) The present invention provides a method for printing melt electro-writing curves using a melt electro-writing curve printing device based on translational-rotational coordinated motion. Through translational-rotational coordinated motion, the jet posture remains unchanged, thereby ensuring the stability of the jet state. There is no jet instability caused by jet turning in traditional equipment, nor is there any deviation between the design path and the fiber pattern caused by jet lag. It also eliminates the cause of fiber diameter fluctuations, and can achieve high-quality printing of curve supports.

[0058] (2) The present invention provides a melt electro-writing curve printing device based on translational-rotational coordinated motion. The device monitors the jet hysteresis in real time through a stationary visual monitoring unit and adjusts the voltage to keep the jet hysteresis length stable. By combining real-time monitoring of jet hysteresis with dynamic voltage control, the device overcomes the problem of increased jet hysteresis caused by residual charge, which leads to interlayer offset in curve printing. This fundamentally solves the accuracy and consistency problems in melt electro-writing printing of complex curve structures.

[0059] (3) The melt electro-writing curve printing method based on translational-rotational coordinated motion of the present invention is particularly suitable for fields with extremely high requirements for geometric accuracy and material uniformity, such as complex tissue engineering scaffolds, flexible electronic devices and micro-nano structures, and provides an effective solution for the application of melt electro-writing technology in the manufacturing of high-precision complex structures. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the overall structure of the melt electro-writing curve printing device based on translational-rotational coordinated motion of the present invention.

[0061] Figure 2 The diagram below illustrates the operating principle of an existing XYZ three-axis translational device. In the diagram, (a) represents a clockwise rotation angle of 0°, (b) represents a clockwise rotation angle of 45°, and (c) represents a clockwise rotation angle of 90°. The solid black lines represent the jet, and the dashed black lines represent the projection lines of the nozzles (i.e., the lines connecting the preset paths of the nozzles). The solid blue lines represent the movement trajectory of the nozzles relative to the platform (designed path), and the dashed red lines represent the actual movement trajectory.

[0062] Figure 3 The schematic diagram of the melt electro-writing curve printing device of the present invention with translational-rotational coordinated motion is shown in which (a) is a platform rotating counterclockwise 0º, (b) is a platform rotating counterclockwise 45º, and (c) is a platform rotating counterclockwise 90º.

[0063] Figure 4 The following are comparison diagrams of printing effects in embodiments of the present invention: (a) is a preset diagram of the printing support trajectory of the melt electro-writing curve printing device of the present invention with translational-rotational coordinated motion; (b) is a diagram of the actual printing effect of the present invention; and (c) is a diagram of the printing effect of the existing XYZ three-axis translational device.

[0064] Among them, 1-translational module, 2-rotation module, 3-servo motor, 4-nozzle, 5-collection plate, 6-industrial camera, 7-high pressure generator. Detailed Implementation

[0065] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0066] A melt electro-writing curve printing device based on translational-rotational coordinated motion, such as Figure 1 As shown, it includes a nozzle 4, a collection plate 5, a high-voltage generator 7 that provides voltage to the nozzle, a composite motion platform, a vision monitoring unit, and a control system;

[0067] The collecting plate 5 is a square aluminum alloy collecting plate with a side length of 20 mm and a thickness of 5 mm. The collecting plate 5 is grounded by connecting it with a wire.

[0068] The distance between nozzle 4 and collection plate 5 is 3 mm;

[0069] The composite motion platform is used to support the collection plate 5. The composite motion platform is driven by the translation module 1 and the rotary module 2 located below it. The translation module 1 is used to drive the composite motion platform to perform planar translational motion, and the rotary module 2 is used to drive the translation module 1 and the collection plate 5 to rotate together around a vertical fixed axis. The collection plate 5 is rigidly connected to the external threaded joint at the moving end of the translation module 1 through an M4 internal threaded hole.

[0070] The translation module 1 uses a servo motor 3 to achieve translation in the X, Y, and Z coordinate axes; the repeatability of the X and Y axes is ±5 μm, and the repeatability of the Z axis is ±8 μm.

[0071] Rotary module 2 uses servo motor 3 to achieve R-axis rotation;

[0072] The visual monitoring unit is an industrial camera 6, which is used to acquire the hysteresis length of the jet between the nozzle 4 and the collection plate 5 in real time.

[0073] The control system is electrically connected to the translation module 1, the rotation module 2, the vision monitoring unit, and the high-voltage generator 7;

[0074] The control system is configured to: control the translation module 1 and the rotation module 2 to move in coordination according to the preset motion control information; receive the jet hysteresis length fed back by the visual monitoring unit and compare it with the set value; and dynamically adjust the output voltage of the high voltage generator according to the comparison result.

[0075] A method for melt electro-writing curve printing using the aforementioned melt electro-writing curve printing device based on translational-rotational coordinated motion, taking polycaprolactone fiber scaffold as an example, includes the following specific steps:

[0076] S1: Determining and initializing printing process parameters;

[0077] Printing process parameters include: stable extrusion flow rate Q of the polymer melt; and the diameter of the target fiber to be printed. Theoretical platform translational linear velocity V; Voltage setpoint of high-voltage generator Jet hysteresis length setting value ;

[0078] S11: Determining Q:

[0079] Gas pressure propelled the extrusion of polycaprolactone (PCL, molecular weight 25,000 Da) melt. After stable droplets formed at the nozzle exit, the voltage of the high-voltage generator was slowly increased to 3.0 kV, causing the droplets to be stretched into a continuous jet by the electric field. The collecting plate was fixed in a stationary state, and the jet deposit was collected on the collecting plate directly below the nozzle for 5 minutes. The polymer melt extrusion flow rate Q was determined by weighing and then calculated using the formula... The calculated polymer melt extrusion flow rate is Q = 1.579 × 10⁻⁶. −6 cm 3 / s=0.095 μL / min;

[0080] in, For sediment quality, =0.54 mg, For the time of sediment collection; For polymer density, =1.14g / cm 3 ;

[0081] S12: Determining V:

[0082] Based on the target fiber diameter , =20 μm, through the mass conservation equation of a circular cross-section fiber Calculate the required theoretical platform translational velocity V = 4.77 mm / s;

[0083] S13: and Determination:

[0084] Reset the collection plate and control the translation module at a speed Linear printing was performed, and the voltage of the high-voltage generator was adjusted. The position of the jet deposition point was observed in real time through the visual monitoring unit. When the voltage rose to 3.5 kV, printing was continued for 60 seconds to confirm that there was no drift in the deposition point. The stable jet hysteresis length setting value at this time was recorded. =1.5mm, voltage setting value of high voltage generator =3.5 kV;

[0085] S2: Path planning and motion parameter preprocessing;

[0086] S21: Designing using Python, such as Figure 4 The continuously printed curve trajectory shown in (a) is exported as a TXT file, imported into a preprocessing program, and then subjected to equal arc length discrete sampling to obtain a series of discrete path points. The arc length between adjacent points It is 0.1 mm;

[0087] S22: At the starting point of the discrete path Previously, a section of length was added. The straight path, The value is 10 cm, and this straight path coincides with the preset continuous printing curve trajectory. Points tangent;

[0088] S23: Based on discrete path points The unit tangent vector at each point is calculated using the central difference method. curvature and the unit tangent vector at that point With the initial tangent vector (i.e., the first waypoint) The angle between the directions of the unit tangent vector at the location ; =0.2 mm -1 ;

[0089] , and The calculation formula is as follows:

[0090] ;

[0091] = , where (·) represents the vector dot product;

[0092] ;

[0093] S24: Based on the preset translational linear velocity of the composite motion platform and the curvature of each discrete path point According to the formula Calculate the angular velocity required for the rotating module at each corresponding point. ; =5 mm / s × 0.2 mm -1 =1 rad / s;

[0094] S3: Cooperative motion printing and real-time feedback control;

[0095] S31: Set the high-voltage generator voltage to... After observing the stable deposition of the jet, the composite motion platform was controlled to move along a path sequence. Motion, in which the translational module moves at a speed The drive platform translates while the rotating module moves to each point. At that time, with angular velocity Drive the composite motion platform to rotate to the angle ;

[0096] S32: During the printing process, the visual monitoring unit captures a real-time image of the jet every 10 ms, and the control system calculates the actual hysteresis length of the jet. ;

[0097] S33: Real-time comparison by the control system With the jet hysteresis length setting value , =1.8mm> =1.5mm, feedback control of the high-voltage generator increases the output voltage until... = At this time, the voltage is 3.9kV to maintain Constant to Nearby; the control system uses a closed-loop control method to regulate the voltage of the high-voltage generator. The closed-loop control method is proportional-integral-derivative control, and the final printed pattern is as follows. Figure 4 As shown in (b).

[0098] like Figure 2 As shown, Figure 2 In diagrams (a), (b), and (c), the clockwise turning angles are 0°, 45°, and 90°, respectively. As the turning angle gradually increases, the deviation between the jet trajectory and the nozzle's motion trajectory relative to the platform continuously increases, and the deviation between the actual motion trajectory and the designed path becomes increasingly significant. Simultaneously, the fluctuation in jet length intensifies. This phenomenon indicates that the existing XYZ three-axis translational device cannot eliminate jet inertia; the larger the turning angle, the more significant the decrease in printing accuracy, making it difficult to meet the printing requirements of complex curved paths.

[0099] like Figure 3 As shown, Figure 3In diagrams (a), (b), and (c), the platform rotates counterclockwise by 0°, 45°, and 90°, respectively. Through the synchronized linkage of the translation and rotation modules, the inertial effect during the printing process is actively eliminated at the motion control level, making the jet flow tend towards "quasi-static" stability in space. This fundamentally solves the problems of trajectory distortion and fiber unevenness in curve printing. Therefore, this invention, through the synchronized linkage of the translation and rotation modules, can fundamentally solve the problem of jet flow instability in curve printing, ultimately achieving high-precision and highly consistent printing of complex curves.

[0100] By comparison Figure 4 As can be seen from (a), (b), and (c) in the figures, the method of the present invention significantly improves printing accuracy. Figure 4 (a) is the preset printing trajectory, which is the target geometric shape to be achieved during printing; Figure 4 (c) shows the printing effect of the existing XYZ three-axis translation device. Due to the continuous change of the printing direction, the stretching state of the jet is always in a dynamic adjustment process, which causes the jet lag length to fluctuate continuously throughout the printing process. This makes the printing trajectory deviation and fiber diameter unevenness exhibit global characteristics, significantly reducing the overall accuracy and stability of the formed structure. Figure 4 Image (b) shows the printing effect of the melt electro-writing curve printing device of the present invention, which features translational-rotational coordinated motion. The trajectory is consistent with... Figure 4 In (a), the preset trajectory is highly aligned, the fiber diameter is uniform, and there is no obvious deviation or structural defect. The core reason is that the present invention adopts a translational-rotational coordinated motion architecture. The translational module drives the collection plate to macroscopically translate along the preset trajectory, and the rotational module dynamically calculates and compensates for the angular velocity based on the real-time curvature of the path and the translational speed, driving the translational module and the collection plate to rotate synchronously. This effectively eliminates the jet inertial effect and keeps the jet in a "quasi-static" stable state in space, thus avoiding trajectory deviation from the root. At the same time, the visual monitoring unit acquires the jet lag length in real time, and the control system suppresses the lag length fluctuation by controlling the output voltage of the high-voltage generator through closed-loop regulation. Combined with the stable supply control of polymer melt, the fiber diameter consistency is further guaranteed, thereby achieving a higher precision printing effect and completely solving the problem that the existing technology is unable to balance the accuracy of the curved printing trajectory and the consistency of the fiber diameter.

Claims

1. A melt electro-writing curve printing device based on translational-rotational coordinated motion, comprising a nozzle, a collection plate, and a high-voltage generator providing voltage to the nozzle, characterized in that: It also includes a composite motion platform, a visual monitoring unit, and a control system; The composite motion platform is used to support the collection plate. The composite motion platform is driven by a translation module and a rotating module located below it. The translation module is used to drive the composite motion platform to perform planar translational motion, and the rotating module is used to drive the translation module and the collection plate to rotate together around a vertical fixed axis. The visual monitoring unit is used to acquire the hysteresis length of the jet between the nozzle and the collection plate in real time; The control system is electrically connected to the translation module, rotation module, vision monitoring unit, and high-voltage generator; The control system is configured to: control the translation module and the rotation module to move in coordination according to the preset motion control information; receive the jet hysteresis length fed back by the visual monitoring unit and compare it with the set value; and dynamically adjust the output voltage of the high voltage generator according to the comparison result.

2. The melt electro-writing curve printing device based on translational-rotational coordinated motion according to claim 1, characterized in that, The translation module uses servo motors to achieve translation in the X, Y, and Z coordinate axes; The rotating module uses a servo motor to achieve R-axis rotation.

3. The melt electro-writing curve printing device based on translational-rotational coordinated motion according to claim 1, characterized in that, The collecting plate is a square aluminum alloy collecting plate with a side length of 20 mm and a thickness of 5 mm. The collecting plate is grounded by connecting wires. The distance between the nozzle and the collection plate is 3 mm.

4. The melt electro-writing curve printing device based on translational-rotational coordinated motion according to claim 1, characterized in that, The visual monitoring unit is an industrial camera.

5. A method for printing melt electro-writing profiles using the apparatus according to any one of claims 1 to 4, characterized in that... Includes the following steps: S1: Determining and initializing printing process parameters; S2: Path planning and motion parameter preprocessing; S21: Perform equal-arc-length discrete sampling on the preset continuous printed curve trajectory to obtain a series of discrete path points. The arc length between adjacent points is ; S22: At the starting point of the discrete path Previously, a section of length was added. A straight path, which coincides with a preset continuous printing curve trajectory. Points tangent; S23: Based on discrete path points The unit tangent vector at each point is calculated using the central difference method. curvature and the unit tangent vector at that point With the initial tangent vector The angle between the directions ; S24: Based on the preset translational linear velocity of the composite motion platform and the curvature of each discrete path point According to the formula Calculate the angular velocity required for the rotating module at each corresponding point. ; S3: Cooperative motion printing and real-time feedback control; S31: Set the high-voltage generator voltage to... After observing the stable deposition of the jet, the composite motion platform was controlled to move along a path sequence. Motion, in which the translational module moves at a speed The drive platform translates while the rotating module moves to each point. At that time, with angular velocity Drive the composite motion platform to rotate to the angle ; S32: During the printing process, images are captured in real time by a vision monitoring unit, and the actual hysteresis length of the jet is calculated by the control system. ; S33: Real-time comparison by the control system With the jet hysteresis length setting value ,like > If the feedback control increases the output voltage, the high-voltage generator will increase it; otherwise, it will decrease it to maintain the output voltage. Constant to nearby.

6. The method according to claim 5, characterized in that, The printing process parameters in step S1 include: a stable extrusion flow rate Q of the polymer melt, which is 0.05~0.5 μL / min; and the target fiber diameter for printing. The theoretical platform translational linear velocity V is 5~50 μm; the voltage setpoint of the high-voltage generator is 3~15 mm / s. The voltage is 3.0~4.5 kV; the jet hysteresis length setting value is... The thickness is 0.1~2 mm.

7. The method according to claim 5, characterized in that, In step S21, It is 0.1 mm.

8. The method according to claim 5, characterized in that, In step S22, It is 10 cm.

9. The method according to claim 5, characterized in that, In step S23, , and The calculation formula is as follows: ； = ； 。 10. The method according to claim 5, characterized in that, In step S33, the control system uses a closed-loop control method to regulate the voltage of the high-voltage generator. The closed-loop control method is proportional-integral-derivative control or model predictive control.

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