Gas assisted ink direct write ink extrusion device and method of use thereof

Abstract

The present application relates to the field of precision machining of additive manufacturing, and discloses a gas-assisted pen ink direct writing ink extrusion device and a use method thereof, wherein an outer nozzle and an inner nozzle are installed at the nozzle in an expandable manner; the output end of a gas source is connected to the input end of the air injection channel of the outer nozzle and the inner nozzle respectively, so that the air introduced into the inner nozzle cavity is injected into the nozzle, a gas film is covered on the surface of the ink during the ink flow, and the viscoelastic material is prevented from adhering to the nozzle to cause nozzle blockage; the existence of the gas film makes the ink surface smooth, the printed wire bundle is more round, and a plurality of power valves are arranged between the outer nozzle and the output end of the gas source, the air injection channel of the outer nozzle is controlled by controlling the power valves, air with a certain temperature is injected, the abnormal stress distribution of the ink at the nozzle outlet is eliminated, and the larger head caused by extrusion expansion at the beginning of printing is eliminated, so that the stability of the pen ink direct writing 3D printing product is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing precision machining, specifically to a gas-assisted pen ink direct writing extrusion device and its usage method. Background Technology

[0002] Pen-to-pen 3D printing technology is highly customizable and less dependent on external conditions. Currently, its applications are becoming increasingly widespread.

[0003] Generally, due to the highly customizable nature of pen-to-pen printing, shear-thinning viscoelastic materials are typically used as inks. In this process, the shear-thinning properties of the viscosity reduce the polymer's viscosity upon entering the nozzle, allowing the polymer fluid to flow out of the nozzle under relatively low pressure. The elastic properties also ensure that the polymer fluid maintains its printed shape well after flowing out of the nozzle and onto the platform. However, the extrusion expansion effect of the viscoelastic fluid itself causes a large head to form after the ink flows out of the nozzle in the initial stages of pen-to-pen printing. This extrusion expansion effect and the resulting head lead to abnormal residual stress within the printed wire bundle. Furthermore, once the elasticity increases to a certain level, the excessively large head can break the printed wire bundle, affecting the quality of the pen-to-pen printed product. This problem is caused by the inherent properties of viscoelastic materials and therefore requires external assistance to solve. Currently, in the published relevant patents CN 112265261 A and CN 105235220 A, improvements to the nozzle and external conditions (gas assistance) are primarily based on fused deposition modeling (FDM). No gas assistance specifically for pen-to-pen printing has been found so far.

[0004] Furthermore, since the direction of the nozzle is fixed at any given moment, the extruded ink only exists behind the nozzle relative to the direction of movement. Using an outer nozzle that can be individually controlled and disassembled is beneficial for energy saving.

[0005] Therefore, providing a solution for the abnormal wire bundle stress and large head caused by the extrusion expansion effect in pen-to-ink 3D printing, while also considering energy saving, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In order to overcome the defects of the prior art, the present invention aims to provide a gas-assisted pen ink direct writing ink extrusion device and its usage method, so as to solve the technical problems of extrusion expansion caused by viscoelasticity, abnormal stress distribution, and poor printing quality in the existing pen ink direct writing printing technology.

[0007] This invention is achieved through the following technical solution:

[0008] A gas-assisted pen ink direct writing extrusion device includes a nozzle, an outer nozzle, an inner nozzle, a gas source, and a gas injection control device. Both the outer and inner nozzles have internal gas injection channels. The nozzle orifice end is fitted onto the inner nozzle, and the outer nozzle is fitted onto the outside of the inner nozzle. The output end of the gas source is connected to the input ends of the gas injection channels of both the outer and inner nozzles. A plurality of power valves are provided between the output end of the gas source and the input end of the gas injection channel of the outer nozzle, arranged around the input end of the gas injection channel of the outer nozzle. The drive end of the gas injection control device is connected to the control ends of the plurality of power valves.

[0009] Preferably, the air injection channel of the outer nozzle is configured to run through the outer nozzle from top to bottom.

[0010] Preferably, several baffles are arranged in a ring around the outer nozzle in the air injection channel. The baffles extend from the top to the bottom of the outer nozzle, and air injection channel areas are formed between adjacent baffles. Each air injection channel area corresponds to a power valve.

[0011] Preferably, the air injection channel of the inner nozzle extends into the inner nozzle along the top of the inner nozzle, wherein a plurality of annular air injection channels are provided on the inner sidewall of the inner nozzle, and the plurality of annular air injection channels are perpendicular to and connected to the air injection channel of the inner nozzle.

[0012] Furthermore, several gas injection nozzles are distributed on each annular gas injection channel.

[0013] Furthermore, the cross-sectional structure of the annular gas injection channel can be any one of rectangular, rhomboid, or trapezoidal shapes.

[0014] Preferably, a gate valve is provided at the output end of the gas source, and the output end of the gas source is branched after passing through the gate valve. One branch is connected to the gas injection channel input end of the inner nozzle, and the other branch is connected to the gas injection channel input end of the outer nozzle. Each branch is equipped with a heat exchanger. The pipeline before the gas source output end passes through the heat exchanger is a cold air duct, and the pipeline after the gas source output end passes through the heat exchanger is a hot air duct.

[0015] Preferably, sealing rings are provided at the pipe interfaces between the gas source, gate valve, cold air duct, heat exchanger, hot air duct, and the outer and inner nozzles.

[0016] A method for using a gas-assisted pen ink direct-writing ink extrusion device, based on the aforementioned gas-assisted pen ink direct-writing ink extrusion device, is as follows:

[0017] After passing through the nozzle, the ink reaches the input end of the inner nozzle. Simultaneously, compressed air from the air source passes through a gate valve and is split, flowing into the air injection channels of the inner and outer nozzles respectively through a heat exchanger. The compressed air in the air injection channel of the inner nozzle is ejected along the output end of the nozzle, causing the ink inside the nozzle to flow out through the compressed air. The air injection control device controls the power valve to control the compressed air in the air injection channel of the outer nozzle, so that the ink, after flowing out of the inner nozzle, is heated by the compressed gas ejected from the air injection channel of the outer nozzle. During this process, the ink continuously flows down, completing the pen-to-ink printing process under the conditions of adjusting the air supply of the outer nozzle according to the direction of movement and continuous air supply of the inner nozzle.

[0018] Preferably, the gas transmission pipeline between the gas source and the outer and inner nozzles is made of pressure- and temperature-resistant material.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] This invention provides a gas-assisted pen-to-ink direct writing ink extrusion device. It features an extended outer nozzle and an inner nozzle at the nozzle tip. The output of the air source is connected to the input of the air injection channels of both the outer and inner nozzles, allowing air introduced into the inner nozzle cavity to pass through. As the ink flows down, an air film forms on its surface, preventing the viscoelastic material from adhering and clogging the tiny nozzle. Furthermore, the air film smooths the ink surface, resulting in more rounded printed lines. Several power valves are located between the outer nozzle and the air source output. These valves control the air injection channel of the outer nozzle, introducing warm air to eliminate abnormal stress distribution at the nozzle exit and the large head caused by extrusion expansion at the beginning of printing. Controlling the airflow speed also allows for adjustment of the printed line height, effectively improving the stability of pen-to-ink direct writing 3D printed products and greatly ensuring their customization capabilities.

[0021] Furthermore, the air injection channel of the outer nozzle runs through the top and bottom of the outer nozzle, allowing the compressed air in the air injection pipe of the outer nozzle to be aligned with the falling ink, eliminating abnormal stress distribution of ink at the nozzle exit and large head caused by extrusion expansion at the beginning of printing, thus improving print quality.

[0022] Furthermore, several baffles are arranged in a ring around the outer nozzle within the air injection channel. These baffles extend from the top to the bottom of the outer nozzle, forming an air injection channel area between adjacent baffles. Each air injection channel area corresponds to a power valve, and each control valve corresponds to an air injection channel area. This allows for flexible assistance in controlling the falling ink, thereby improving the ink printing quality.

[0023] Furthermore, the air injection channel of the inner nozzle extends into the inner nozzle along the top of the inner nozzle. Several annular air injection channels are formed on the inner sidewall of the inner nozzle. These annular air injection channels are perpendicular to and connected to the air injection channel of the inner nozzle. During the ink flow, an air film covers its surface. On the one hand, this ensures that the viscoelastic material does not stick in the small nozzle and cause nozzle blockage. On the other hand, the presence of the air film makes the ink surface smooth, and the printed line bundle is more rounded.

[0024] Furthermore, each annular air injection channel is equipped with several air injection nozzles. These nozzles eject compressed air from the inner nozzles, causing an air film to cover the surface of the ink as it flows down. This ensures that the viscoelastic material does not stick inside the tiny nozzles and cause nozzle blockage. At the same time, the presence of the air film makes the ink surface smoother, resulting in more rounded printed lines.

[0025] Furthermore, a gate valve is installed at the output end of the air source. After passing through the gate valve, the output end of the air source is branched. One branch connects to the air injection channel input end of the inner layer nozzle, and the other branch connects to the air injection channel input end of the outer layer nozzle. Each branch is equipped with a heat exchanger. The pipeline before the heat exchanger at the output end of the air source is a cold air channel, and the pipeline after the heat exchanger at the output end of the air source is a hot air channel. This ensures the supply of compressed air to the air injection channels of the outer and inner layer nozzles. At the same time, the cold air channel can pass through the heat exchanger and the hot air channel to eliminate the abnormal stress distribution formed by ink at the cylindrical outlet and the large head caused by extrusion expansion at the beginning of printing.

[0026] Furthermore, sealing rings are installed at the pipe interfaces between the gas source, gate valve, cold air duct, heat exchanger, hot air duct, and the outer and inner nozzles to effectively prevent gas leakage.

[0027] This invention also provides a method for using a gas-assisted ink extrusion device. By diverting air from the high-pressure gas source outlet, it ensures that the inner and outer nozzle air sources have different temperatures and pressures. By setting independent and detachable external nozzles and matching control power valves, different numbers of nozzles are equipped according to different printing modes. The air injection control device ensures that the outer nozzle behind the cylindrical nozzle is always open. The residual stress in the printed line bundle is eliminated by air with a certain temperature, avoiding product surface quality problems caused by extrusion expansion effect. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the nozzle system of the gas-assisted ink extrusion device in this invention;

[0029] Figure 2This is a schematic diagram of the pen-to-ink direct writing 3D printing system of the gas-assisted ink extrusion device in this invention;

[0030] Figure 3 This is a partial three-dimensional schematic diagram of the double-layer nozzle in this invention;

[0031] Figure 4 This is a schematic diagram of different cross-sections of the inner nozzle of the double-layer nozzle in this invention;

[0032] In the diagram: 1-Nozzle; 2-Outer nozzle; 3-Inner nozzle; 4-Gas source; 5-Gate valve; 6-Cold air duct; 7-Heat exchanger; 8-Hot air duct; 9-Power valve; 10-Signal line; 11-Gas injection control device; 12-Computer; 13-Power supply; 14-Control equipment; 15-Slide rail controller; 16-Slide rail; 17-Moving platform; 21-Baffle; 31-Annular gas injection channel; 32-Gas injection nozzle. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0034] The present invention will now be described in further detail with reference to the accompanying drawings:

[0035] The purpose of this invention is to provide a gas-assisted pen ink direct writing extrusion device and its usage method to solve the technical problems of extrusion expansion caused by viscoelasticity, abnormal stress distribution, and poor printing quality in existing pen ink direct writing printing technology.

[0036] See Figure 1 In one embodiment of the present invention, a gas-assisted pen ink direct writing extrusion device is provided, including a nozzle 1, an outer nozzle 2, an inner nozzle 3, an air source 4, and an air injection control device 11; both the outer nozzle 2 and the inner nozzle 3 are provided with air injection channels inside, the nozzle 1's nozzle end is fitted onto the inner nozzle 3, the outer nozzle 2 is fitted onto the outside of the inner nozzle 3, the output end of the air source 4 is connected to the input end of the air injection channel of the outer nozzle 2 and the inner nozzle 3 respectively, and a plurality of power valves 9 are provided between the output end of the air source 4 and the input end of the air injection channel of the outer nozzle 2, the plurality of power valves 9 being arranged around the input end of the air injection channel of the outer nozzle 2, and the drive end of the air injection control device 11 being connected to the control end of the plurality of power valves 9.

[0037] Specifically, the air injection channel of the outer nozzle 2 is configured to run through the outer nozzle 2 from top to bottom;

[0038] This allows the compressed air in the air injection pipe of the outer nozzle to be aligned with the falling ink, eliminating abnormal stress distribution of the ink at the nozzle exit and the large head caused by extrusion expansion at the beginning of printing, thus improving print quality.

[0039] Specifically, several baffles 21 are arranged in a ring along the air injection channel of the outer nozzle 2. The baffles 21 are arranged through the top and bottom of the outer nozzle 2, and air injection channel areas are formed between adjacent baffles 21. Each air injection channel area corresponds to a power valve 9, and each control valve corresponds to an air injection channel area, which facilitates flexible assistance to the falling ink and improves the ink printing quality.

[0040] Specifically, the air injection channel of the inner nozzle 3 extends into the inner nozzle 3 along the top of the inner nozzle 3. Several annular air injection channels 31 are formed on the inner sidewall of the inner nozzle 3. The several annular air injection channels 31 are perpendicular to and connected to the air injection channels of the inner nozzle 3. During the ink flow, an air film covers its surface. On the one hand, it ensures that the viscoelastic material does not stick in the small nozzle and cause nozzle blockage. On the other hand, the presence of the air film makes the ink surface smooth and the printed line bundle is more rounded.

[0041] Each annular air injection channel 31 has several air injection nozzles 32. The air injection nozzles spray compressed air into the inner nozzle, so that an air film covers the surface of the ink as it flows down. This ensures that the viscoelastic material does not stick in the small nozzle and cause nozzle blockage. At the same time, the presence of the air film makes the ink surface smooth, and the printed line bundle is more rounded.

[0042] In this invention, the cross-sectional structure of the annular gas injection channel 31 can be any one of a rectangle, rhombus, or trapezoid, such as... Figure 4 As shown.

[0043] Specifically, a gate valve 5 is provided at the output end of the air source 4. After passing through the gate valve 5, the output end of the air source 4 is branched. One branch is connected to the air injection channel input end of the inner nozzle 3, and the other branch is connected to the air injection channel input end of the outer nozzle 2. Each branch is equipped with a heat exchanger 7. The pipeline before passing through the heat exchanger 7 at the output end of the air source 4 is the cold air channel 6, and the pipeline after passing through the heat exchanger 7 at the output end of the air source 4 is the hot air channel 8. This ensures the supply of compressed air to the air injection channels of the outer and inner nozzles. At the same time, the cold air channel can pass through the heat exchanger and the hot air channel to eliminate the abnormal stress distribution formed by the ink at the cylindrical outlet and the large head caused by the extrusion expansion at the beginning of printing.

[0044] Specifically, sealing rings are installed at the pipe interfaces between the gas source 4, gate valve 5, cold air duct 6, heat exchanger 7, hot air duct 8, and outer nozzle 2 and inner nozzle 3 to effectively prevent gas leakage.

[0045] In another embodiment of the present invention, a method for using a gas-assisted pen ink direct writing extrusion device is provided. Based on the gas-assisted pen ink direct writing extrusion device described above, the specific process is as follows:

[0046] After passing through nozzle 1, the ink reaches the input end of the inner nozzle 3. At the same time, the compressed air in the air source 4 passes through the gate valve 5 and is split, and is injected into the air injection channels of the inner nozzle 3 and the outer nozzle 2 through the heat exchanger 7. The compressed air in the air injection channel of the inner nozzle 3 is ejected along the output end of nozzle 1, so that the ink in nozzle 1 flows out through the compressed air. The air injection control device 11 controls the power valve 9 to control the compressed air in the air injection channel of the outer nozzle 2, so that the ink is heated by the compressed gas ejected through the air injection channel of the outer nozzle 2 after flowing out of the inner nozzle 3. During this process, the ink continues to flow down, completing the pen-to-ink printing process under the condition of adjusting the air supply of the outer nozzle 2 according to the direction of movement and the continuous air supply of the inner nozzle 3.

[0047] The gas transmission pipeline between the gas source 4 and the outer nozzle 2 and the inner nozzle 3 is made of pressure-resistant and temperature-resistant material.

[0048] In this invention, the inner nozzle 3 is installed outside the nozzle 1 as an extension. The nozzle 1 has a cylindrical structure. The outer nozzle 2 can be detachably installed outside the inner nozzle 3. The gas source 4, gate valve 5, heat exchanger 7, and power valve 9 are connected in sequence through pipelines. The gas source 4 usually uses a gas cylinder. During the gas injection process, the pressure will decrease as the gas content in the cylinder decreases. In order to stably supply gas to the system, the gas source 4 is supplied to the system at a lower pressure than its rated pressure. The high-pressure cold gas output from the gas source 4 is diverted through the cold gas channel 6 and then exchanges heat with the heat exchanger to obtain hot gas with a certain temperature. The portion diverted to the inner layer is continuously supplied through the annular opening inside the nozzle. As the printing direction changes, the gas injection control device monitors its movement direction and opens the power valve at the outer nozzle 2, which is opposite to the printing direction, through the control device.

[0049] The inner nozzle 3 is installed outside the nozzle 1 as an extension. It has annular channels at equal intervals inside, and gas at a certain temperature is continuously introduced into the nozzle 1 to form a gas film on the ink surface. This cleans the inner wall of the cylindrical nozzle 1 while maintaining the stability of the printing wire bundle. The independent and detachable outer nozzle 2 is arranged outside the inner nozzle 3. Each outer nozzle has an arc-shaped nozzle at the bottom. The opening and closing of the outer nozzle is controlled by a separately set power valve 9 and an air injection control device 11.

[0050] In this invention, the inner nozzle 3 is made of a heat-resistant material. Air at a certain temperature is introduced and supplied to the cylindrical nozzle through an annular channel inside, forming a stable gas film on the ink surface. Figure 3 As shown, annular channels with different cross-sections have different effects on ink. The uniform cross-section downward inclined structure promotes the smooth extrusion of high-viscosity materials along the ink flow direction. The scaling annular channel prevents the ink from being blown off by the deceleration characteristics of the nozzle, and can also increase the contact area between air and ink.

[0051] The outer nozzle 2 is made of heat-resistant material. Air at a certain temperature is introduced and sprayed onto the printed wire harness along the lower arc-shaped nozzle. The air with a certain speed and temperature blows onto the wire harness, eliminating the wire harness head formed by the extrusion expansion effect unique to viscoelastic materials. In addition, for the subsequent stable printing stage, the air with a certain temperature is beneficial to eliminate the residual stress distribution inside the ink just leaving the nozzle.

[0052] The gas-assisted ink extrusion device provided by this invention operates as follows during printing:

[0053] according to Figure 2 As shown, the computer 12 models the object to be printed and modifies the model into a code that the control device 14 can recognize through software. The power supply 13 supplies power to the control device 14. The control device 14 controls the slide rail controller 15 to operate the nozzle 1 on the slide rail 16 according to the code of the computer 12. After the ink is extruded into the nozzle 1, the front gate valve 5 of the air source 4 opens, the air is split and heated, and then a stream enters the inner layer nozzle 3 to continuously supply air. It enters the inside of the spray group through the annular channel to form an air film. The air injection control device 11 monitors the direction of nozzle movement and controls the outer layer nozzle 2 behind it to open in the corresponding direction. By blowing a certain temperature airflow downward, the wire harness printing head is eliminated and the residual stress inside the wire harness is balanced. During the printing process, the moving platform 17 moves with the movement of the nozzle 1.

[0054] In summary, this invention provides a gas-assisted ink extrusion device and its usage method. By connecting an inner nozzle 3 to the outside of the nozzle 1 and arranging an outer nozzle 2 on the outer wall of the inner nozzle 3, continuous air supply is provided to the annular channel on the inner wall of the inner nozzle 3 to form an air film on the ink surface, ensuring a relatively rounded surface and thus printing a stable line bundle. The gas injection control device monitors the movement direction of the cylindrical nozzle and transmits a signal to the independently controllable outer nozzle behind it, opening the power valve and spraying gas at a certain temperature from the corresponding fan-shaped nozzle. This reduces the large initial print head caused by the viscoelasticity of the ink, thereby avoiding the risk of breakage. On the other hand, the air at a certain temperature helps to eliminate the abnormal distribution of residual stress inside the line bundle, making the printed line bundle more stable.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A gas-assisted pen ink direct-writing extrusion device, characterized in that, It includes a nozzle (1), an outer nozzle (2), an inner nozzle (3), an air source (4), and an air injection control device (11); the outer nozzle (2) and the inner nozzle (3) are both provided with air injection channels. The nozzle (1) is fitted on the inner nozzle (3), and the outer nozzle (2) is fitted on the outside of the inner nozzle (3). The output end of the air source (4) is connected to the input end of the air injection channel of the outer nozzle (2) and the inner nozzle (3) respectively. Several power valves (9) are provided between the output end of the air source (4) and the input end of the air injection channel of the outer nozzle (2). Several power valves (9) are arranged around the input end of the air injection channel of the outer nozzle (2). The driving end of the air injection control device (11) is connected to the control end of several power valves (9). The gas source (4) is provided with a gate valve (5) at its output end. After passing through the gate valve (5), the output end of the gas source (4) is branched. One branch is connected to the gas injection channel input end of the inner nozzle (3), and the other branch is connected to the gas injection channel input end of the outer nozzle (2). Each branch is provided with a heat exchanger (7). The pipeline before the output end of the gas source (4) passes through the heat exchanger (7) is the cold air channel (6), and the pipeline after the output end of the gas source (4) passes through the heat exchanger (7) is the hot air channel (8).

2. The gas-assisted pen ink direct-writing extrusion device according to claim 1, characterized in that, The air injection channel of the outer nozzle (2) extends from the top to the bottom of the outer nozzle (2).

3. The gas-assisted pen ink direct-writing extrusion device according to claim 1, characterized in that, The outer nozzle (2) has several baffles (21) arranged in a ring along the outer nozzle (2) in the air injection channel. The baffles (21) are arranged through the outer nozzle (2) from top to bottom. An air injection channel area is formed between adjacent baffles (21), and each air injection channel area corresponds to a power valve (9).

4. The gas-assisted pen ink direct-writing extrusion device according to claim 1, characterized in that, The air injection channel of the inner nozzle (3) extends into the inner nozzle (3) along the top of the inner nozzle (3), wherein a plurality of annular air injection channels (31) are provided on the inner sidewall of the inner nozzle (3), and the plurality of annular air injection channels (31) are perpendicular to and connected to the air injection channel of the inner nozzle (3).

5. The gas-assisted pen ink direct-writing extrusion device according to claim 4, characterized in that, Several gas injection nozzles (32) are distributed on each annular gas injection channel (31).

6. The gas-assisted pen ink direct-writing extrusion device according to claim 4, characterized in that, The cross-sectional structure of the annular gas injection channel (31) can be any one of rectangular, rhomboid or trapezoidal.

7. The gas-assisted pen ink direct-writing extrusion device according to claim 1, characterized in that, Sealing rings are provided at the pipe interfaces between the gas source (4), gate valve (5), cold air duct (6), heat exchanger (7), hot air duct (8), and outer nozzle (2) and inner nozzle (3).

8. A method of using a gas-assisted pen ink direct-writing extrusion device, based on the gas-assisted pen ink direct-writing extrusion device according to any one of claims 1-7, characterized in that, The specific process is as follows: After passing through the nozzle (1), the ink reaches the input end of the inner nozzle (3). At the same time, the compressed air in the air source (4) passes through the gate valve (5) and is divided, and is injected into the air injection channels of the inner nozzle (3) and the outer nozzle (2) through the heat exchanger (7). The compressed air in the air injection channel of the inner nozzle (3) is ejected along the output end of the nozzle (1), so that the ink in the nozzle (1) flows out through the compressed air. The air injection control device (11) controls the power valve (9) to control the compressed air in the air injection channel of the outer nozzle (2), so that the ink is heated by the compressed gas injected through the air injection channel of the outer nozzle (2) after flowing out of the inner nozzle (3). During this process, the ink flows down continuously, completing the pen ink direct writing printing process under the conditions of adjusting the air supply of the outer nozzle (2) and the continuous air supply of the inner nozzle (3) according to the direction of movement.

9. The method of using a gas-assisted pen ink direct writing extrusion device according to claim 8, wherein the gas supply pipe material between the gas source (4) and the outer nozzle (2) and the inner nozzle (3) is made of pressure-resistant and temperature-resistant material.

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