CN114892281B - Curved surface receiving method and spinning device based on near-field direct writing of melt - Google Patents

Abstract

The invention discloses a curved surface receiving method and a spinning device based on melt near-field direct writing. The method for determining the tip of the needle can be used for melt near-field direct writing on receiving devices with different geometric structures and curvatures, and meets the preparation requirement of a non-planar fiber support. The melt near-field direct writing device is braked by a three-axis control system, and the distance between the needle head and the curved surface receiving device is kept constant. When the deposition height of the fiber is larger, the receiving distance and the voltage are compensated, the stability of the jet flow in an electric field is ensured, and finally, the deposition is carried out on the surface of the curved surface receiving device according to the preset path, so that the deviation between the actual path and the preset path is effectively reduced.

Description

A curved surface receiving method and spinning device based on melt near-field direct writing

technical field

The invention belongs to the field of melt near-field direct writing technology and 3D printing technology, and specifically relates to a melt near-field direct writing curved surface receiving method and a spinning device.

Background technique

Melt Electrowriting (MEW) is an emerging intelligent manufacturing technology that combines melt electrospinning and 3D printing. This technology reduces the receiving distance of melt electrospinning, so that the jet reaches the receiving device before the whipping occurs. At the same time, it is supplemented by the X-Y axial movement sliding table receiving device. Through the path planning of the moving sliding table, the micron fiber can be achieved. Precise positioning, exhibiting a high level of controllability in terms of fiber deposition location, fiber morphology and fiber tissue structure. The fiber of the scaffold prepared by the near-field melt electrostatic direct writing technology has the characteristics of controlled deposition, and the preparation process does not require solvents, and the prepared material is non-toxic, which is a lower pressure, safer and more environmentally friendly spinning The method has greatly promoted the application of this technology in the fields of tissue engineering, clinical medicine, etc., especially in the process of manufacturing bionic implantable scaffolds, which has the advantage of easy structure regulation.

In the melt near-field direct writing technology, various process parameters such as voltage, receiving distance, receiving speed, etc. need to be balanced and matched to ensure the stability of the jet in the electric field. Most current collection devices for near-field direct writing are planar receivers, however, human tissues (such as articular cartilage) are usually non-planar due to the natural three-dimensional structural arrangement, and the mechanical similarity between biomaterial scaffolds and tissues ( structure and performance) contribute to more efficient tissue regeneration. Therefore, in order to better meet the application requirements of the tissue structure, it is urgent to break through the technical problem of orderly fiber deposition on the curved surface, so as to realize the fiber manufacturing of the three-dimensional structure on the curved surface receiving device, and increase the variety of melt near-field direct writing technology. and expand the field of application of this technology.

Contents of the invention

The purpose of the present invention is to provide a curved surface receiving method and spinning device based on melt near-field direct writing, so as to realize the fiber structure manufacturing of melt near-field direct writing on receiving devices such as regular geometric curved surfaces and curved surfaces.

In order to solve the above technical problems, the following technical solutions are adopted:

A melt near-field direct writing curved surface receiving spinning device, including a spinning head mechanism, a platform, and a curved surface receiving device, is characterized in that the spinning device also includes an X-axis moving mechanism, a Y-axis moving mechanism and a Z-axis moving mechanism. Mechanism, the Y-axis moving mechanism is installed on the X-axis moving mechanism to drive the Y-axis moving mechanism to move horizontally; the platform is installed on the Y-axis moving mechanism to drive the platform to move longitudinally, and the platform is installed with a curved surface receiving device; the Z-axis moving mechanism is installed with a spinning head mechanism. Drive the spinning head mechanism to move vertically, and the spinning head mechanism spins to the curved surface receiving device.

Further, the spinning head mechanism includes a gas delivery pipe, a heating device, a temperature measuring device, a heat insulation cylinder and a syringe. The temperature measurement device, the heating device and the syringe are installed in the heat insulation cylinder, and the gas delivery pipe is connected to the syringe, and the gas delivery pipe is connected to There is an air pressure valve, and a digital display screen is installed on the air pressure valve to display the air pressure inside the syringe; the barrel body of the syringe is placed in the heating device, the needle of the syringe passes through the heat insulation cylinder, and the needle is connected to a high-voltage power supply. The heat insulation cylinder has the effect of heat insulation and heat preservation. The heating device heats the syringe to convert the polymer into a polymer melt; the temperature measuring device monitors the temperature of the syringe in real time, which is convenient for the operator to grasp the temperature condition in real time, and can be used when the temperature is out of balance. Respond promptly. The air tube is used to control the air pressure in the syringe, thereby regulating the extrusion rate of the syringe.

Further, the X-axis moving mechanism includes an X-axis motor, an X-axis screw and an X-axis sliding table, and the Y-axis moving mechanism includes a Y-axis motor, a Y-axis screw and a Y-axis sliding table, and the X-axis motor is connected to the X-axis screw, the X-axis The X-axis sliding table is installed on the shaft screw, the Y-axis screw is installed on the X-axis sliding table, the Y-axis screw is connected to the Y-axis motor, the Y-axis sliding table is installed on the Y-axis screw, and the Y-axis sliding table is installed on the platform; the Z-axis moves The mechanism includes a Z-axis motor, a Z-axis screw and a Z-axis sliding table, the Z-axis motor is connected to the Z-axis screw, the Z-axis sliding table is installed on the Z-axis screw, and the Z-axis sliding table is connected to the spinning head mechanism through a fixing plate. The present invention designs the connection relationship of the three-axis moving mechanism. The Y-axis moving mechanism that moves longitudinally is connected to the X-axis moving mechanism through the Y-axis sliding table, and then the X-axis sliding table of the X-axis moving mechanism is connected to the platform, so that the platform can be moved immediately. The X-axis moving mechanism is controlled and controlled by the Y-axis moving mechanism to realize horizontal and vertical translation. The Z-axis moving mechanism connects the spinning head mechanism through the Z-axis slide table to realize the vertical translation of the spinning head mechanism, so that the receiving distance can be adjusted. Based on the three-axis moving mechanism, the three-axis direction in the space can be adjusted arbitrarily, perfect It meets the spinning requirements received on the curved surface device, and the design is ingenious.

A curved surface receiving method based on melt near-field direct writing, characterized in that it comprises the following steps:

(1) Obtain the spatial geometric coordinates of the surface of the curved surface receiving device: calculate the surface geometric coordinates of the curved surface receiving device through Python, and obtain the spatial geometric coordinate set of the curved surface receiving device;

(2) Obtain the spatial trajectory coordinates of the needle head: According to the coordinate information generated in the above step (1), and control the distance between the needle head and the curved surface receiving device, so that the needle head and the curved surface receiving device maintain a constant distance H; and then calculate and obtain the needle head The space trajectory coordinates of ;

(3) According to the spatial geometric coordinate set of the curved surface receiving device and the spatial trajectory coordinates of the needle, generate the needle coordinate displacement command executed by the three-axis motor; import the needle coordinate displacement command into the three-axis control system, and the three-axis control system follows this The needle coordinate displacement command controls the X-axis moving mechanism, the Y-axis moving mechanism and the Z-axis moving mechanism;

(4) As the height of the deposited fiber increases, the height between the needle and the top fiber needs to be compensated, and the COMSOL software is used to simulate the spinning electric field model to determine the electric field strength between the needle and the surface of the curved receiving device. And the voltage regulation is implemented through the voltage control program to ensure the force stability of the jet in the electric field.

(5) Execute the printing operation according to step (3) and step (4).

After optimization, the calculation process of step (1): first extract and segment the y coordinates of the (x, y, z) three-dimensional coordinates, obtain all the y coordinate sets after segmentation, and segment the corresponding x coordinates on the y coordinates, Obtain all coordinate sets of (x, y), bring the x and y coordinates into the sphere equation, obtain the corresponding z coordinate, and finally obtain the (x, y, z) space geometric coordinate set of the surface receiving device; the sphere equation is:

x ² +y ² +z ² =r ²

where r represents the radius of the sphere.

After optimization, step (4) melt near-field direct writing electric field model simulation: two-dimensional modeling of the spinning device, the conductivity setting of the material is defined according to the actual conductivity; the simulation of the electric field change in the spinning process is to The electric field strength between the needle and the surface of the curved receiving device is simulated physically, the electric field strength of the needle at different positions is determined, and the voltage regulation and compensation are performed through the voltage control program. To ensure the stability of the jet in the electric field through the simulation of the electric field, the position of the needle needs to be corrected to achieve accurate deposition. The distance between the needle and the curved receiver is kept constant. As the needle moves over the curved receiver, the needle's motion path is adjusted, during which the needle's position is projected vertically onto the curved surface. As printing progresses, the fiber height of the deposited portion increases, and the distance between the tip of the fiber tip and the top layer of the fiber decreases. In order to ensure the stability of the jet flow and avoid the insufficient curing of the top layer of fibers due to the influence of the heat source, the position of the tip of the needle will be fine-tuned, and the voltage will be adjusted at the same time, so that the best electric field strength between the needle and the curved surface receiving device will remain stable. Polymer jetting and repeatable printing.

Preferably, after spinning printing 20 layers, the voltage is increased at a constant voltage for each layer. Ensure jet stability and continuous and orderly deposition.

After optimization, step (5): the curved surface receiving device is manufactured by 3D printing method, and its geometric shape, curvature, and size can be defined in the three-dimensional design software.

After optimization, step (5): before printing, add the polymer masterbatch into the syringe, first preheat the polymer masterbatch, and discharge the internal bubbles of the polymer melt after preheating to obtain a uniform polymer melt; After the melt is evenly heated, the polymer melt is extruded by the controllable pneumatic device, the air pressure valve is controlled, and the air pressure is supplied to the inside of the syringe through the air pipe; when the polymer melt begins to appear at the needle of the syringe, a DC power supply is applied to the needle. Voltage: After the voltage is turned on, the polymer melt forms a stable jet in the electrostatic electric field and is drawn into filaments in the air, and finally solidifies into an ordered fiber structure on the curved surface receiving device.

After optimization, step (4): Before printing, operate the X-axis moving mechanism, Y-axis moving mechanism and Z-axis moving mechanism to move the needle head into contact with the edge of the curved surface receiving device, and raise the Z-axis moving mechanism upward by H, and then Set the Y-axis position coordinates as the zero point of the Y-axis; move the X-axis moving mechanism and the Y-axis moving mechanism to make the zero point in the needle coordinate displacement command correspond to the preset space zero point, and perform the zero-returning operation.

Owing to adopting above-mentioned technical scheme, have following beneficial effect:

The invention is a curved surface receiving method and spinning device based on near-field direct writing of the melt. The method can realize fiber collection of the near-field direct writing of the melt on the curved surface device. By designing the movement track of the needle, it can ensure that the needle and the curved surface The constant distance between the receiving devices realizes the collection of ordered fibers on the curved surface receiving devices and the preparation of functional morphological fiber scaffolds. Its beneficial effect is embodied as:

1. The spinning head mechanism of the present invention is installed on the Z-axis moving mechanism, and its motion trajectory can be designed through point coordinates, which is convenient for controlling the distance between the spinning head mechanism and the curved surface receiving device, so as to obtain the spinning position required by the design. standard.

2. The present invention corrects the motion trajectory of the spinneret device by acquiring the spatial geometric coordinates of the surface of the curved surface receiving device, so as to ensure a constant distance between the spinneret tip and the curved surface receiving device.

3. The method for determining the position of the tip of the needle in the present invention can not only be used on a receiving device with a linear slope, but also can be used on a receiving device with a nonlinear curved surface. Write process requirements.

4. When the fiber deposition height is large, as the deposited fiber height increases, it is necessary to adjust the distance between the spinning tip and the fiber surface, and at the same time ensure the stability of the electric field intensity. The COMSOL physical model is used to simulate the regulation of the guiding voltage. Ensure the stability of the jet in the electric field, and finally deposit on the surface of the curved receiving device according to the preset path, effectively reducing the deviation between the actual path and the preset path.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing:

Fig. 1 is the perspective view of spinning device;

Fig. 2 is the schematic diagram of the front view direction of spinning device;

Fig. 3 is the schematic diagram of spinning device left view direction;

Fig. 4 is the schematic diagram of spinning device top view direction;

Fig. 5 is the schematic diagram of spinning head mechanism and curved surface receiving device;

Fig. 6 is a schematic diagram of the moving trajectory before and after the needle path optimization;

Fig. 7 is a schematic diagram of the moving trajectory of the needle on the nonlinear curved surface.

Detailed ways

The purpose of the present invention is to provide a curved surface receiving method and spinning device based on near-field direct writing of the melt. This method can realize the collection of fibers on the curved surface by near-field direct writing of the melt. The distance between the receivers is such that the jet is deposited on the surface of the curved receivers according to the preset path. The present invention will be further described below in conjunction with specific embodiment:

1. A near-field direct writing curved surface receiving spinning device

It includes a spinning head mechanism 5, a platform 4, and a curved surface receiving device 6. It is characterized in that the spinning structure also includes an X-axis moving mechanism 1, a Y-axis moving mechanism 2, and a Z-axis moving mechanism 3. The X-axis moving mechanism 1 Install the Y-axis moving mechanism 2 to drive the Y-axis moving mechanism 2 to move laterally; install the platform 4 on the Y-axis moving mechanism 2 to drive the platform 4 to move longitudinally, and install the curved surface receiving device 6 on the platform 4; install the spinning head mechanism on the Z-axis moving mechanism 3 5. Drive the spinning head mechanism 5 to move vertically, and the spinning head mechanism 5 spins to the curved receiving device 6 .

The spinning head mechanism 5 includes a gas delivery pipe 51, a heating device 54, a temperature measuring device 53, a heat insulating cylinder 52 and a syringe 55, and the heat insulating cylinder 52 is installed with a temperature measuring device 53, a heating device 54 and a syringe 55 in sequence from the outside to the inside. , the air delivery pipe 51 is connected to the syringe 55, and the air delivery pipe 51 is connected with an air pressure valve, and the air pressure valve is equipped with a digital display screen to display the air pressure inside the syringe 55; The needle passes through the heat-insulating cylinder 52, and the needle is connected with a DC high-voltage power supply 56.

The heat insulation cylinder 52 has the effect of heat insulation and is made of heat insulation materials. On the one hand, it can reduce internal heat loss, has a good heat preservation effect, and reduces heating energy consumption.

The heating device 54 adopts an electric heating method to heat the syringe 55, the barrel of the syringe 55 is installed in the heating device 54, and the heating device 54 heats the syringe 55 to convert the polymer into a polymer melt;

The temperature measuring device 53 adopts the form of a temperature measuring rod and is installed between the heat insulating cylinder 52 and the heating device 54 to detect the internal temperature. The temperature measuring device 53 monitors the temperature of the injector 55 in real time, which is convenient for the operator to grasp the temperature working conditions in real time, and can respond in time when the temperature is out of balance.

The air delivery pipe 51 is used to control the air pressure in the syringe 55, thereby regulating the extrusion rate of the syringe 55. The air delivery pipe 51 is connected with an air pressure valve to facilitate the adjustment of the air pressure inside the syringe 55; The size of the air pressure enables the operator to grasp the air pressure working conditions.

The syringe 55 includes a barrel body 553 and a needle 552. The barrel body 553 is filled with a polymer melt 551, and the needle 552 forms a jet of the polymer melt 551 for spinning.

The X-axis moving mechanism 1 includes an X-axis motor 11, an X-axis screw 12 and an X-axis sliding table 13, and the Y-axis moving mechanism 2 includes a Y-axis motor 21, a Y-axis screw 22 and a Y-axis sliding table 23, and an X-axis motor 11 Connect the X-axis lead screw 12, install the X-axis slide 13 on the X-axis lead screw 12, install the Y-axis lead screw 22 on the X-axis slide 13, connect the Y-axis lead screw 22 to the Y-axis motor 21, and install on the Y-axis lead screw 22 Y-axis sliding table 23, Y-axis sliding table 23 installation platform 4; Z-axis moving mechanism 3 includes Z-axis motor 31, Z-axis screw 32 and Z-axis sliding table 33, Z-axis motor 31 is connected with Z-axis screw 32, Z A Z-axis slide table 33 is installed on the shaft screw 32 , and the Z-axis slide table 33 is connected with a spinning head mechanism 5 through a fixed plate 34 .

The present invention designs the connection relationship of the three-axis moving mechanism. The vertically moving Y-axis moving mechanism 2 is connected to the X-axis moving mechanism 1 through the Y-axis slide 23, and then the X-axis slide 13 of the X-axis moving mechanism 1 is connected to the platform 4. , so that the platform 4 is not only controlled by the X-axis moving mechanism 1, but also controlled by the Y-axis moving mechanism 2, so as to realize horizontal and vertical translation. The Z-axis moving mechanism 3 is connected to the spinning head mechanism 5 through the Z-axis sliding table 33 to realize the vertical translation of the spinning head mechanism 5, so that the receiving distance can be adjusted. Based on the three-axis moving mechanism, the three-axis directions in the space can be adjusted arbitrarily The purpose perfectly fits the spinning method of curved surface receiving, and the design is ingenious.

2. A surface receiving method based on near-field direct writing of melt

Curved surface receiving device 6 adopts spherical receiving device

(1) Obtain the surface space geometric coordinates of the curved surface receiving device 6: calculate the surface geometric coordinates of the curved surface receiving device 6 through Python, first extract and segment the y coordinates of the (x, y, z) three-dimensional coordinates, and obtain the divided All y coordinate sets of , divide the corresponding x coordinates on the y coordinates to obtain all coordinate sets of (x, y), bring the x and y coordinates into the sphere equation, obtain the corresponding z coordinates, and finally obtain the surface receiving device 6 The (x, y, z) space geometric coordinate set; the sphere equation is:

x ² +y ² +z ² =r ²

where r represents the radius of the sphere.

(2) Obtain the space trajectory coordinates of the needle head 552: the coordinate information of the curved surface receiving device 6 generated according to the above-mentioned steps (1), and control the distance between the needle head 552 and the curved surface receiving device 6, so that the needle head 552 and the curved surface receiving device remain constant The distance is 4mm; then calculate and obtain the spatial trajectory coordinates of the needle 552 through an algorithm;

In order to calculate the position of the needle 552 from the surface of the curved receiving device 6 , the coordinates of the geometric points on the surface of the curved receiving device 6 must first be obtained. Then use vertical (the shortest distance from the needle 552 to the surface of the curved surface receiving device 6) line to form a new path of the needle 552 (such as the optimized trajectory of the needle 552 in Figure 6). Here, another Python algorithm needs to be created to calculate the new position coordinates of the needle relative to the curved surface 552, and generate a list of coordinates of the needle 552 to define the position of the needle 552 during the entire printing process.

Once the curved space position of the curved receiving device 6 is calculated, a vertical distance of 4 mm will be added by an algorithm to determine the position of the needle 552 . During low-layer fiber printing, the needle 552 path will remain in a vertical position 4 mm above the surface of the curved receiver 6 . When printing a thicker fiber scaffold, on the basis of the above steps, fine-tune the Z-axis coordinates of the needle so that the distance between the needle and the top fiber of the scaffold remains constant.

(3) According to the spatial geometric coordinate set of the curved surface receiving device 6 and the spatial trajectory coordinates of the needle head 552, generate the needle head 552 coordinate displacement command executed in coordination with the three-axis motor; import the needle head 552 coordinate displacement command in the three-axis control system, and the three-axis The control system controls the X-axis moving mechanism 1, the Y-axis moving mechanism 2 and the Z-axis moving mechanism 3 according to the needle 552 coordinate displacement command, and controls the movement speed of the three to 500mm/min;

(4) When the number of fiber layers is high, it is necessary to use COMSOL software to simulate the electric field model of the near-field direct writing of the melt; carry out two-dimensional modeling of the spinning device, and the conductivity setting of the material is defined according to the actual conductivity; To simulate the effect of the increase in the height of the deposited fiber on the electric field intensity during the spinning process, as the thickness of the deposited fiber increases, the distance between the needle and the top layer of fiber needs to be raised, and the voltage regulation and compensation are performed through the voltage control program. To ensure the stability of the jet in the electric field through electric field simulation, the position of the needle 552 needs to be corrected to achieve accurate deposition. As the needle head 552 moves above the curved surface receiving device 6, the movement path of the needle head 552 is adjusted. During this process, the position of the needle head 552 is vertically projected on the curved surface surface. As the position of the tip of the needle 552 changes, the magnitude of the voltage is regulated to achieve the best electric field strength and maintain a stable polymer jet and repeatable printing.

After spinning and printing 20 layers, the voltage is increased by 2V per layer to ensure the stability of the jet and deposit accurately according to the preset path.

(5) Execute the printing operation according to step (3) and step (4).

Step 1. The curved surface receiving device is manufactured by 3D printing, and a layer of conductive tin foil is covered on the surface of the curved surface receiving device 6 to facilitate the taking and placing of the prepared fiber support.

Step 2: Take polycaprolactone, add 5g of polycaprolactone masterbatch into the syringe 55, set the preheating temperature to 70°C, and preheat for more than 24 hours to fully discharge the internal bubbles of the polymer melt 551 to obtain a uniform The polymer melt 551.

Step 3: After the melt is evenly heated, the polymer melt 551 is extruded by a controllable pneumatic device, and the air pressure valve is controlled to supply air pressure to the inside of the syringe 55 through the air pipe 51, and the air pressure inside the syringe 55 is adjusted to 2.0 bar.

Step 4. Print the support structure design: use SolidWorks to draw. Determine the geometric structure of the bracket through this software, and export the STL file of the bracket. Convert the STL file into the G-code recognizable by the three-axis control system through the Repetier-Host software, upload the G-code program and the needle 552 position file to the receiving device (X and Y directions) and the spinning head mechanism 5 (Z direction ) in the three-axis control system (using Mach-CNC software), the jet can be deposited on the curved surface receiving device 6 according to the designed pattern or structure. The melt near-field direct writing PCL square grid scaffold is designed as a 35 mm × 35 mm grid with a fiber spacing of 500 μm. The design of the ring structure at the edge of the grid is to prevent the accumulation of the buffer form of the fiber caused by the change of the mechanical running direction.

Step 5. Before printing, operate the X-axis moving mechanism 1, the Y-axis moving mechanism 2 and the Z-axis moving mechanism 3 to move the needle 552 into contact with the edge of the curved surface receiving device 6, and raise the Z-axis moving mechanism 3 upward by H, At this time, set the Y-axis position coordinates as the zero point of the Y-axis; move the X-axis moving mechanism and the Y-axis moving mechanism 2 to correspond the zero point in the needle head 552 coordinate displacement command to the preset spatial zero point, and execute the zeroing operation.

Step 6. When the polymer melt 551 begins to condense at the needle 552 of the syringe 55, start to apply a DC voltage to the needle 552 through a DC power supply; after the voltage is turned on, the polymer melt 551 forms a stable jet in the electrostatic field and is blown in the air. drawn into filaments, and finally deposited on the curved surface receiving device 6 according to the preset path.

During the whole printing process, the height of the needle head 552 is always kept at a constant distance of 4mm from the surface of the curved surface receiving device 6, and the three-axis control system executes the movement of the X-axis moving mechanism 1, the Y-axis moving mechanism 2, and the Z-axis moving mechanism 3, The voltage control program performs voltage regulation and compensation. After printing, spray 70% ethanol on the holder to facilitate removal from the curved receiver.

The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements or modifications based on the present invention to solve basically the same technical problems and achieve basically the same technical effects are covered by the protection scope of the present invention.

Claims (9)

1. A curved surface receiving method based on melt near-field direct writing, its spinning device includes a spinning head mechanism, a platform, and a curved surface receiving device, and the spinning device also includes an X-axis moving mechanism, a Y-axis moving mechanism and a Z axis moving mechanism. Axis moving mechanism, the Y-axis moving mechanism is installed on the X-axis moving mechanism to drive the Y-axis moving mechanism to move laterally; the Y-axis moving mechanism is installed on the platform to drive the platform to move longitudinally. The platform is equipped with the curved surface receiving device; the Z-axis moving mechanism is equipped with the spinning head mechanism, which drives the spinning head mechanism to move vertically, and the spinning head mechanism spins to the curved surface receiving device. Including the following steps: (1) Obtain the spatial geometric coordinates of the curved surface receiving device: calculate the surface geometric coordinates of the curved surface receiving device through Python, and obtain the spatial geometric coordinate set of the curved surface receiving device; (2) Obtain the spatial trajectory coordinates of the needle head: According to the coordinate information generated in the above step (1), and control the distance between the needle head and the curved surface receiving device, so that the needle head and the curved surface receiving device maintain a constant distance H; then calculate and obtain through Python Space trajectory coordinates of the needle; (3) According to the spatial geometric coordinate set of the surface receiving device and the spatial trajectory coordinates of the needle, generate the needle coordinate displacement command executed by the three-axis motor; import the needle coordinate displacement command into the three-axis control system, and the three-axis control system follows this The needle coordinate displacement command controls the X-axis moving mechanism, the Y-axis moving mechanism and the Z-axis moving mechanism; (4) When the fiber deposition height is large, as the deposited fiber height increases, it is necessary to compensate the height between the needle and the top fiber, and use COMSOL simulation software to calculate the electric field between the spinning tip and the surface of the receiving device Simulate and adjust the voltage in time to ensure the stability of the jet in the electric field; (5) Execute the printing operation according to the steps (3) and (4). 2. A curved surface receiving method based on near-field direct writing of melt according to claim 1, characterized in that: the spinning head mechanism includes a gas delivery pipe, a heating device, a temperature measuring device, a heat insulation cylinder and a syringe, A temperature measuring device, a heating device and an injector are installed in the heat-insulating cylinder, the air delivery pipe is connected to the injector, and the air delivery pipe is connected with an air pressure valve, and a digital display screen is installed on the air pressure valve, It shows the air pressure inside the syringe; the barrel of the syringe is placed in the heating device, the needle of the syringe passes through the heat insulation cylinder, and the needle is connected to a high-voltage power supply. 3. A curved surface receiving method based on melt near-field direct writing according to claim 1, characterized in that: the X-axis moving mechanism includes an X-axis motor, an X-axis screw and an X-axis slide table, and the The Y-axis moving mechanism includes a Y-axis motor, a Y-axis screw, and a Y-axis slide. The X-axis motor is connected to the X-axis screw, and the X-axis slide is installed on the X-axis screw. The X The Y-axis lead screw is installed on the shaft slide table, the Y-axis lead screw is connected to the Y-axis motor, the Y-axis slide table is installed on the Y-axis lead screw, and the Y-axis slide table is installed with the platform; The Z-axis moving mechanism includes a Z-axis motor, a Z-axis lead screw and a Z-axis slide table, the Z-axis motor is connected to the Z-axis lead screw, and the Z-axis slide table is installed on the Z-axis lead screw. The Z-axis slide table is connected and installed with the spinning head mechanism through a fixed plate. 4. A curved surface receiving method based on melt near-field direct writing according to claim 1, characterized in that: the calculation process of the step (1): first calculate the three-dimensional coordinates of the curved surface (x, y, z) Extract and segment the y coordinates, obtain all the y coordinate sets after segmentation, segment the corresponding x coordinates on the y coordinates, obtain all coordinate sets of (x, y), bring the x and y coordinates into the sphere equation, and obtain the corresponding z coordinates, and finally obtain the (x, y, z) spatial geometric coordinate set of the surface receiving device; the sphere equation is: ^x2 + ^y2 + ^z2 = ^r2 where r represents the radius of the sphere. 5. A curved surface receiving method based on near-field direct writing of melt according to claim 1, characterized in that: the electric field simulation in the step (4): two-dimensional geometric modeling of the spinning device, the material The conductivity setting is defined according to the actual conductivity; through the physical electric field simulation of the influence of the deposited fiber height on the electric field strength between the needle and the surface of the curved surface receiving device, the electric field strength of the needle at the fine-tuned spatial position is determined, and The voltage is regulated through the execution of the voltage control program. 6 . A method for receiving curved surfaces based on melt near-field direct writing according to claim 5 , wherein the voltage increases at a constant voltage for each layer after spinning and printing 20 layers. 7. A curved surface receiving method based on melt near-field direct writing according to claim 1, characterized in that: said step (5): the structure of the curved surface receiving device can be obtained by 3D printing, and the size or geometry of the curved surface Design in 3D software according to actual use to meet different application requirements. 8. A method for receiving curved surfaces based on melt near-field direct writing according to claim 1, characterized in that: the step (5): before printing, add the polymer masterbatch into the syringe, first polymerize After preheating, the internal air bubbles of the polymer melt are discharged to obtain a uniform polymer melt; after the polymer melt is uniformly heated, the polymer melt is extruded by a controllable pneumatic device, and the air pressure valve is controlled. The trachea supplies air pressure to the inside of the syringe; when the polymer melt begins to appear at the needle of the syringe, a DC voltage is applied to the needle through the DC power supply; after the voltage is turned on, the polymer melt forms a stable jet in the electrostatic field and is drawn into air The filaments are finally deposited on the surface of the curved receiving device according to the preset path. 9. A curved surface receiving method based on melt near-field direct writing according to claim 1, characterized in that: the step (4): before printing, operate the X-axis moving mechanism, the Y-axis moving mechanism and the Z-axis For the movement of the moving mechanism, the needle head is in contact with the edge of the curved surface receiving device, and the Z-axis moving mechanism is raised upward by H, and the Y-axis position coordinate is set as the zero point of the Y-axis; the X-axis moving mechanism and the Y-axis moving mechanism are moved to the The zero point in the needle coordinate displacement instruction corresponds to the preset spatial zero point, and performs zeroing operation.

Images