A metal 3D printing pen based on self-propagating reaction and its usage method

Abstract

This invention provides a metal 3D printing pen based on a self-propagating reaction, comprising a pen tip, a reagent tube, and a pen tail. The reagent tube is detachably connected to the pen tip and pen tail at both ends, respectively. The pen tip has a discharge port. The reagent tube, from the outside in, includes: a shell, a thermal barrier coating, a self-propagating reactor, a high-temperature resistant heat-conducting layer, and a feeding channel. The pen tail includes a feeding port, a power component, an ignition component, and a power source. The power component and the ignition component are respectively connected to the power source. The power component controls the continuous supply of printing material from the feeding port through the feeding channel to the discharge port. The ignition component ignites the self-propagating reactor. This invention combines a self-propagating reaction with a 3D printing pen, reducing the reliance on external energy sources during 3D printing pen use. The detachable connection facilitates part replacement, and the pen is lightweight and portable. It enables the 3D printing of specific shaped metal parts in situations where no additional energy is available, such as in field disaster relief and repair operations, and has broad prospects for promotion and application.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing technology, specifically relating to a metal 3D printing pen based on a self-propagating reaction, and also to a method of using the metal 3D printing pen based on a self-propagating reaction. Background Technology

[0002] 3D printing, also known as additive manufacturing, differs from traditional subtractive manufacturing methods such as turning, milling, planing, grinding, and drilling. It's a process of building objects by layering material from a three-dimensional model. This mold- and blank-free manufacturing method has brought new opportunities to fields such as parts forming and repair. Metal 3D printing is considered the pinnacle of all 3D printing technologies. Metal, as the most widely used material, has significant advantages in terms of strength and hardness. Currently, metal 3D printing technology can be broadly divided into two categories: powder bed fusion technology and directed energy deposition technology. Powder bed fusion technology selectively melts powder layers with thermal energy, such as selective laser sintering and electron beam melting. Directed energy deposition technology melts and deposits materials using focused energy, such as laser-assisted molding and arc additive manufacturing. Printing equipment designed based on these technologies requires continuous external energy input, resulting in significant energy consumption.

[0003] Self-propagating 3D printing utilizes the heat generated by a chemical reaction for self-heating, thus maintaining the reaction and its conduction. This process also releases a large amount of heat to the outside and requires no external heat source (either completely or partially). The speed, temperature, and conversion rate of the process can be controlled by changing the rate of heat release and transfer. Energy-saving 3D printing equipment can be designed using the principle of self-propagating reactions. Patent 201510359577.6 discloses a self-propagating 3D printing device, which includes a worktable, a frame, and a self-propagating reaction-based printing apparatus, providing a low-cost, high-speed 3D printing device. However, the device is relatively large and inconvenient to carry in situations such as field disaster relief and repair.

[0004] Based on this, a metal 3D printing pen based on self-propagating reaction and its usage method are provided. This is of great significance for realizing the rapid 3D printing of metal parts of specific shapes in situations where there is no additional energy, such as in field rescue and repair. It is also a technical problem that urgently needs to be solved. Summary of the Invention

[0005] One of the objectives of this invention is to provide a metal 3D printing pen based on a self-propagating reaction that is simple to manufacture, has a stable reaction, high thermal utilization, is portable, and safe to use.

[0006] The second objective of this invention is to provide a method for using a metal 3D printing pen based on a self-propagating reaction.

[0007] One of the technical solutions adopted to achieve the objective of this invention is: to provide a metal 3D printing pen based on a self-propagating reaction, comprising: a pen tip, a medicine tube, and a pen tail; the two ends of the medicine tube are detachably connected to the pen tip and the pen tail, respectively;

[0008] The pen tip is provided with a discharge port; the medicine tube includes, from the outside to the inside: an outer shell, a thermal barrier coating, a self-propagating reactor, a high-temperature resistant heat-conducting layer, and a feeding channel; the pen tail includes a feeding port, a power component, an ignition component, and a power source; the power component and the ignition component are respectively connected to the power source; the power component is used to control the continuous supply of printing material from the feeding port through the feeding channel to the discharge port; the ignition component is used to ignite the self-propagating reactor.

[0009] The overall concept of a metal 3D printing pen based on a self-propagating reaction provided by this invention is as follows:

[0010] This invention introduces a self-propagating reaction system into 3D printing technology, providing a 3D printing pen that does not rely on external energy. The pen consists of a pen tip, a reagent cartridge, and a pen tail. Considering the reagent cartridge is a consumable that is constantly consumed, this invention makes the cartridge detachable from the pen tip and tail. This not only facilitates the recycling and reuse of the pen tip and tail, but also allows the reagent cartridge to be removed when not in use, making it convenient to carry and effectively preventing safety hazards caused by accidental ignition of the self-propagating reactor during storage and transportation. Furthermore, different self-propagating reactors are required for different printing materials; the detachable design allows for timely replacement of the reagent cartridge to match the melting point of different metal wires, meeting the needs of rapid printing of complex metal parts.

[0011] The pharmaceutical tube of this invention comprises, from the outside in, an outer shell, a thermal barrier coating, a self-propagating reactor, a high-temperature resistant thermally conductive layer, and a feed channel. The self-propagating reactor acts as a heat source, heating the printing material. Considering the high reaction temperature and rapid reaction rate of the self-propagating reaction, the thermal barrier coating effectively isolates the heat released from the self-propagating reactor, ensuring operator safety. The high-temperature resistant thermally conductive layer transfers heat evenly to the feed channel, where the printing material remains semi-molten under high heat, meeting the requirements of subsequent 3D printing.

[0012] The printing pen provided by this invention has a printing material inlet at its end, and also includes a power component, an ignition component, and a power source. The power component and the ignition component are activated by the power source. Specifically, the power component controls the continuous supply of printing material from the inlet through the feeding channel to the outlet; the ignition component ignites the self-propagating reactor. Under the combined action of the power component and the ignition component, the printing material is heated to a semi-molten state by the self-propagating reactor and continuously extruded from the outlet at the pen tip, thereby achieving the 3D printing operation.

[0013] Furthermore, the two ends of the medicine tube are threadedly connected to the pen tip and pen tail, respectively. The end of the medicine tube connected to the pen tip has a head thread, and the end of the medicine tube connected to the pen tail has a tail thread. The pen tip and pen tail are respectively provided with internal threads that match the head thread and tail thread.

[0014] Furthermore, in this invention, considering the control of the reaction temperature and heat release rate of the self-propagating reactor, the self-propagating reactor is configured to consist of two parts: an exothermic agent and a diluent. The exothermic agent, by weight fraction, comprises: 20.0 wt.%–45.0 wt.% Fe3O4 powder, 10.0 wt.%–40.0 wt.% CuO powder, and 20.0 wt.% Al powder; the diluent comprises 20.0 wt.%–30.0 wt.%. Further, the diluent is selected from one or more of wollastonite powder, silica fume, and Si3N4 powder.

[0015] The exothermic agent is used to generate the heat required for 3D printing, and the addition of a diluent can absorb some of the heat released by the exothermic agent, reducing the rate and temperature of the combustion reaction. In this invention, by adjusting the different proportions of the components of the exothermic agent and the amount of diluent, the temperature and heat generation rate of 3D printing for different types of metal wires can be controlled.

[0016] Preferably, the particle size of Fe3O4 powder and CuO powder is 250-300 mesh, the particle size of Al powder is 150-300 mesh, and the particle size of the diluent is 400-500 mesh. In this invention, the particle size of the reactants in the self-propagating reactor also greatly affects the reaction rate. By adjusting the particle size of the reactants, the reaction rate can also be reduced.

[0017] Preferably, the thermal barrier coating is made of ReTaO4 (ferroelastic rare earth tantalate), wherein RE is selected from at least one of Sc, Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb, and Lu. ReTaO4 has different types of chemical bonds (Ta-O bonds are covalent bonds, Re-O bonds are ionic bonds), a twisted polyhedral structure, and a low average phonon velocity. The large mass of the unit cell causes anharmonic effects. These characteristics result in low thermal conductivity and excellent thermal insulation performance. Furthermore, the thickness of the thermal barrier coating is 1.5–2.5 mm.

[0018] Preferably, the high-temperature resistant thermally conductive layer comprises one or more of SiC ceramics, Al2O3 ceramics, and Si3N4 ceramics. These ceramics have high melting points, ensuring they are not damaged during printing, and possess suitable thermal conductivity, keeping the metal wire in a semi-molten state. The high-temperature resistant thermally conductive layer effectively utilizes self-propagating heat, reducing energy loss; furthermore, it separates the 3D printing material from the self-propagating reactor, preventing contamination of the 3D printing material. The thickness of the thermally resistant layer is further specified as 0.8–1.2 mm.

[0019] Furthermore, the power assembly includes a feed button, a motor, and gears. The motor and feed button are connected in series. The printing material is continuously fed along the rotation direction of the gears. Preferably, the gears are distributed on both sides of the printing material to ensure that the printing material is evenly stressed on both sides during feeding, ensuring continuous vertical feeding.

[0020] Preferably, the ignition assembly includes an ignition switch and a wire; the self-propagating reactor has an ignition section on the side near the pen tip; the electric ignition head of the ignition section is connected to the ignition switch via a wire.

[0021] In some preferred embodiments, the electric ignition head of the ignition section is connected to the threaded end of the cartridge via a wire, and this threaded end is made of a conductive material. Furthermore, a spring contact is provided at the internal thread of the cartridge end, and the ignition switch is connected in series with the spring contact via a wire. The spring contact prevents poor contact after repeated use of the cartridge end. When the cartridge and the cartridge end are connected by a thread, the cartridge and the ignition assembly form a closed circuit.

[0022] Preferably, the power source is a detachable battery, with the power component and ignition component connected in parallel, and then connected in series with the battery as a whole.

[0023] Furthermore, the printing material is selected from metal wires with a melting point of 600–1400°C. Preferably, the metal wire is made of materials such as steel, copper alloy, aluminum, silver, or gold.

[0024] Preferably, the pen tip is made of stainless steel and can be reused; the pen tip is also equipped with a thermal barrier coating to improve safety and prevent burns during operation.

[0025] Preferably, the outer shell of the propellant tube is made of stainless steel to prevent the propellant tube from rusting or breaking during storage and transportation, and to prevent the self-propagating reactor from becoming damp and failing.

[0026] The second technical solution adopted by the present invention to achieve the objective is: to provide a method for using a metal 3D printing pen based on a self-propagating reaction as described in the first objective of the present invention, comprising the following steps:

[0027] S1. Connect the pen tip and pen tail to the medicine tube respectively;

[0028] S2. Start the ignition assembly, connect the ignition circuit, and ignite the self-propagating reactor;

[0029] S3. Add printing material through the feed port, start the power unit to continuously feed the printing material, and 3D printing can be performed.

[0030] In the above-described method of use, firstly, the pen tip, the chemical tube, and the pen tail are connected to form the overall structure of the printing pen; secondly, the ignition circuit is connected by activating the ignition assembly, igniting the self-propagating reactor and releasing heat; finally, the printing material is added through the feed inlet, and under the action of the power assembly, the printing material enters the feed channel of the chemical tube from the feed inlet. The heat generated by the combustion of the self-propagating reactor is transferred to the feed channel through the high-temperature resistant heat-conducting layer, making the printing material semi-molten. Under the action of the power assembly, the semi-molten printing material continues to be extruded from the feed channel to the discharge port to meet the subsequent printing modeling requirements.

[0031] In some preferred embodiments, the method of using the self-propagating reaction-based metal 3D printing pen includes the following steps:

[0032] S1. Connect the pen tip and pen tail to the threads at both ends of the medicine tube through their respective internal threads, so that the spring contact at the pen tail is in close contact with the thread at the end of the medicine tube.

[0033] S2. Press the ignition switch to start the ignition assembly, connect the ignition circuit, and the propellant head of the electric igniter will burn, igniting the ignition section, and then igniting the self-propagating reactor, releasing heat.

[0034] S3. Insert the printing filament into the feed port, press the feed button to start the power unit, so that the printing filament is continuously fed. Hold the end of the printing pen to start 3D printing.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] (1) The present invention provides a metal 3D printing pen based on a self-propagating reaction, which combines a self-propagating reaction with a 3D printing pen, overcoming the limitation of traditional 3D printing that relies on a large amount of external energy and significantly reducing energy consumption. The metal 3D printing pen based on a self-propagating reaction provided by the present invention has a simple structure. The pen tip, the chemical tube, and the pen tail are detachably assembled, making it lightweight and easy to carry, and ensuring safety during transportation. In addition, different chemical tubes can be replaced according to specific printing needs, and the pen tip and pen tail can be reused to meet the 3D printing needs of different materials, while saving the overall manufacturing and use costs of the printing pen.

[0037] (2) The present invention provides a metal 3D printing pen based on a self-propagating reaction. The printing tube comprises, from the outside in, an outer shell, a thermal barrier coating, a self-propagating reactor, a high-temperature resistant heat-conducting layer, and a feeding channel. The thermal barrier coating effectively isolates the combustion heat of the self-propagating reactor, ensuring a safe and reliable printing process. The self-propagating reactor provides energy for softening the printing material through combustion. The high-temperature resistant heat-conducting layer effectively transfers the self-propagating heat, reducing energy loss, and also isolates the self-propagating reactor from the printing material, preventing contamination of the printing material. The power component and ignition component at the end of the pen can ignite the self-propagating reactor and ensure a continuous supply of printing material.

[0038] (3) The self-propagating reaction-based metal 3D printing pen provided by this invention has no limitation on the printing area during use. When the heat energy of the printing tube is exhausted, a printing tube with a similar formula can be replaced to continue printing. By adjusting the formula composition of the self-propagating layer inside the printing tube, it supports 3D printing of metals with different melting points. The 3D printing pen provided by this invention does not require holding a match or lighter to ignite the fuse during printing, improving the safety of the printing operation. There is no exposed fuse, and it also avoids accidents where the welding rod ignites when exposed to an open flame without the user's knowledge. This printing pen can realize the 3D printing of metal parts of specific shapes in situations where there is no additional energy, such as in field rescue and repair operations, and has broad prospects for promotion and application. Attached Figure Description

[0039] Figure 1 A schematic diagram of the overall structure of a metal 3D printing pen based on a self-propagating reaction provided in an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of the longitudinal section of the drug tube of a metal 3D printing pen based on a self-propagating reaction provided in an embodiment of the present invention;

[0041] Figure 3 A schematic cross-sectional view of the drug tube of a metal 3D printing pen based on a self-propagating reaction provided in an embodiment of the present invention;

[0042] Figure 4 A schematic diagram of the pen tail of a metal 3D printing pen based on a self-propagating reaction provided in an embodiment of the present invention;

[0043] The components are as follows: 1-pen tip; 11-discharge port; 2-medicine tube; 21-outer shell; 22-thermal barrier coating; 23-self-propagating reactor; 24-high temperature resistant heat-conducting layer; 25-feed channel; 26-ignition section; 261-electric ignition head; 3-pen tail; 31-feed port; 32-power component; 321-feed button; 322-motor; 323-gear; 33-ignition component; 331-ignition switch; 332-wire; 34-power supply; 35-spring contact; 4-printing material. Detailed Implementation

[0044] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0046] Please see Figure 1-4 This invention provides a metal 3D printing pen based on a self-propagating reaction, comprising: a pen tip 1, a reagent tube 2, and a pen tail 3; the two ends of the reagent tube 2 are respectively connected to the pen tip 1 and the pen tail 3 via threads; the pen tip 1 has a discharge port 11; the reagent tube 2 includes, from the outside to the inside: a shell 21, a thermal barrier coating 22, a self-propagating reactor 23, a high-temperature resistant heat-conducting layer 24, and a feed channel 25; both the pen tip 1 and the shell 21 are made of stainless steel, and the pen tip 1 also has a thermal barrier coating for heat insulation. The pen tail 3 includes a feed port 31, a power component 32, an ignition component 33, and a power source 34; the power component 32 and the ignition component 33 are respectively connected to the power source 34; wherein, the power component 32 is used to control the continuous supply of printing material 4 from the feed port 31 through the feed channel 25 to the discharge port 11; the ignition component 33 is used to ignite the self-propagating reactor 23.

[0047] In an embodiment of the present invention, the power assembly 32 includes a feed button 321, a motor 322, and a gear 323. The feed button 321 is connected to the battery compartment, and the gear 323 is mounted on the motor 322. The gear 323 rotates to move the printing material, thereby achieving continuous feeding of the printing material.

[0048] In an embodiment of the present invention, the ignition assembly 33 includes an ignition switch 331 and a wire 332; the self-propagating reactor 23 has an ignition section 26 on the side near the pen tip 1; the electric ignition head 261 of the ignition section 26 is connected to the ignition switch 331 via the wire 332, the wire 332 passes through the flux and is connected to the conductive thread at the tail of the flux tube 2, and the threaded part at the pen tail is provided with a spring contact 35, the spring contact and the ignition switch 331 are connected to the battery compartment via the wire. When the pen tail is engaged with the flux tube 2, pressing the ignition switch 331 can realize the ignition operation. In the present invention, the connection relationship of the ignition assembly can also take other forms, which are not limited here.

[0049] Furthermore, the power supply 34 includes a battery slot and a removable battery. A battery (size 7 battery is used in this embodiment) is installed in the battery slot. The motor 322, the feed button 321 and the battery are connected in series with wires. The ignition switch 331 and the spring contact 35 located at the end of the pen 3 thread are connected in series with the battery through wires 332. The power component and the ignition component are connected in parallel.

[0050] During printing, firstly, the pen tip 1 and pen tail 3 are connected to the threads at both ends of the propellant tube through their respective internal threads, so that the spring contact 35 of the pen tail 3 is in close contact with the thread at the tail of the propellant tube 2; secondly, the ignition switch 331 is pressed to start the ignition assembly 33, which connects the ignition circuit, and the propellant head of the electric ignition head 261 burns, igniting the ignition section, and then igniting the self-propagating reactor 23, releasing heat; finally, the metal wire required for printing is inserted through the feed port 31, the feed button 321 is pressed to start the power assembly 32, so that the metal wire is continuously fed, and 3D printing can be performed by holding the pen tail.

[0051] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0052] Example 1

[0053] like Figure 1-4 As shown, a 3D printing pen based on a self-propagating reaction includes a pen tip 1, a drug tube 2, and a pen tail 3. The pen tip 1 is connected to the drug tube 2 via a head thread. The drug tube 2 consists of an outer shell 21, a thermal barrier coating 22, a self-propagating reactor 23, and a high-temperature resistant thermally conductive layer 24 from the outside to the inside. The head of the drug tube has an ignition section 26, and an electric igniter 261 is located inside the ignition section 26.

[0054] In the drug tube 2, 25.0 wt.% Fe3O4 powder with a particle size of 300 mesh, 35.0 wt.% CuO powder with a particle size of 300 mesh, and 20.0 wt.% Al powder with a particle size of 300 mesh are selected; the diluent is 20.0 wt.% wollastonite with a particle size of 500 mesh, which serves as a self-propagating reactor; the thermal barrier coating is YTaO4 with a thickness of about 2 mm; and the high-temperature resistant thermally conductive layer is SiC ceramic with a thickness of about 1 mm.

[0055] The pen tail 3 is connected to the medicine tube 2 via a tail thread. The pen tail has a built-in battery slot and a motor 322. A gear 323 is placed on the motor 322. The battery slot is connected to the feed button 321 and the ignition switch 331. The top of the pen tail 3 is a metal 3D printing filament feed port 31.

[0056] Insert a No. 7 battery into the battery compartment, connect the motor 322 and the feed button 321 in series with a wire, connect the ignition switch 331 and the spring contact 35 in series, and connect the feed button 321 and the motor 322 as a whole and the ignition switch 331 and the spring contact 35 as a whole in parallel.

[0057] Draw the outline of a five-pointed star on the operating table. Screw the pen tip 1 and pen tail 3 onto both ends of the propellant tube 2. After tightening, the spring contact 35 of the pen tail 3 will make tight contact with the thread at the end of the propellant tube. Press the ignition switch 331, and the ignition circuit will be connected instantly. The propellant head of the electric igniter will ignite, igniting the ignition section, and then igniting the self-propagating reactor, releasing heat. Insert the steel wire into the feed port 31 and lightly touch the feed button 321. The steel wire will continue to feed. Hold the end of the printing pen and guide the wire along the outline to print a steel five-pointed star. The printing process is stable and controllable. After water cooling, the steel five-pointed star is well formed.

[0058] Example 2

[0059] like Figure 1-4 As shown, a 3D printing pen based on a self-propagating reaction includes a pen tip 1, a drug tube 2, and a pen tail 3. The pen tip 1 is connected to the drug tube 2 via a head thread. The drug tube 2 consists of an outer shell 21, a thermal barrier coating 22, a self-propagating reactor 23, and a high-temperature resistant thermally conductive layer 24 from the outside to the inside. The head of the drug tube has an ignition section 26, and an electric igniter 261 is located inside the ignition section 26.

[0060] In the drug tube 2, 40.0 wt.% Fe3O4 powder with a particle size of 270 mesh, 15.0 wt.% CuO powder with a particle size of 300 mesh, and 21.0 wt.% Al powder with a particle size of 300 mesh are selected; the diluent is 24.0 wt.% silicon micro powder with a particle size of 500 mesh as a self-propagating reactor; the thermal barrier coating is YTaO4 with a thickness of about 2 mm; the high-temperature resistant thermally conductive layer is Al2O3 ceramic with a thickness of about 1 mm.

[0061] The pen tail 3 is connected to the medicine tube 2 via a tail thread. The pen tail has a built-in battery slot and a motor 322. A gear 323 is placed on the motor 322. The battery slot is connected to the feed button 321 and the ignition switch 331. The top of the pen tail 3 is a metal 3D printing filament feed port 31.

[0062] Insert a No. 7 battery into the battery compartment, connect the motor 322 and the feed button 321 in series with a wire, connect the ignition switch 331 and the spring contact 35 in series, and connect the feed button 321 and the motor 322 as a whole and the ignition switch 331 and the spring contact 35 as a whole in parallel.

[0063] Draw the outline of a key on the operating table. Screw the pen tip 1 and pen tail 3 onto both ends of the propellant tube 2. After tightening, the spring contact 35 of the pen tail 3 will make tight contact with the thread at the end of the propellant tube. Press the ignition switch 331, and the ignition circuit will be connected instantly. The propellant head of the electric igniter will ignite, igniting the ignition section and then the self-propagating reactor, releasing heat. Insert the copper alloy wire into the feed port 31 and lightly touch the feed button 321. The copper alloy wire will be continuously fed. Hold the end of the printing pen and guide the wire along the outline to print the copper alloy wire key. The printing process is stable and controllable. After water cooling, the copper alloy wire key is well formed.

[0064] Example 3

[0065] like Figure 1-4 As shown, a 3D printing pen based on a self-propagating reaction includes a pen tip 1, a drug tube 2, and a pen tail 3. The pen tip 1 is connected to the drug tube 2 via a head thread. The drug tube 2 consists of an outer shell 21, a thermal barrier coating 22, a self-propagating reactor 23, and a high-temperature resistant thermally conductive layer 24 from the outside to the inside. The head of the drug tube has an ignition section 26, and an electric igniter 261 is located inside the ignition section 26.

[0066] In the drug tube 2, 40.0 wt.% Fe3O4 powder with a particle size of 250 mesh, 10.0 wt.% CuO powder with a particle size of 250 mesh, and 20.0 wt.% Al powder with a particle size of 300 mesh are selected; the diluent is 30.0 wt.% Si3N4 powder with a particle size of 500 mesh as a self-propagating reactor; the thermal barrier coating is YTaO4 with a thickness of about 2 mm; the high-temperature resistant thermally conductive layer is Si3N4 ceramic with a thickness of about 1 mm.

[0067] The pen tail 3 is connected to the medicine tube 2 via a tail thread. The pen tail has a built-in battery slot and a motor 322. A gear 323 is placed on the motor 322. The battery slot is connected to the feed button 321 and the ignition switch 331. The top of the pen tail 3 is a metal 3D printing filament feed port 31.

[0068] Insert a No. 7 battery into the battery compartment, connect the motor 322 and the feed button 321 in series with a wire, connect the ignition switch 331 and the spring contact 35 in series, and connect the feed button 321 and the motor 322 as a whole and the ignition switch 331 and the spring contact 35 as a whole in parallel.

[0069] Draw the outline of the nut on the operating table. Screw the pen tip 1 and pen tail 3 onto both ends of the propellant tube 2. After tightening, the spring contact 35 of the pen tail 3 will make tight contact with the thread at the end of the propellant tube. Press the ignition switch 331, and the ignition circuit will be connected instantly. The propellant head of the electric igniter will ignite, igniting the ignition section, and then igniting the self-propagating reactor, releasing heat. Insert the aluminum wire into the feed port 31 and lightly touch the feed button 321. The aluminum wire will continue to be fed. Hold the end of the printing pen and guide the wire along the outline. After printing one layer, continue printing on top of this layer to print an M20 specification aluminum nut. The printing process is stable and controllable. After water cooling, the M20 aluminum nut is well formed.

[0070] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.

Claims

1. A method for using a metal 3D printing pen based on a self-propagating reaction, characterized in that, Includes the following steps: S1. Connect the pen tip (1) and pen tail (3) to the medicine tube (2) respectively; S2. Start the ignition assembly (33), connect the ignition circuit, and ignite the self-propagating reactor (23). S3. Add printing material (4) through the feed port (31), start the power assembly (32) to continuously feed the printing material (4), and 3D printing can be performed; When the heat of the printing tube is exhausted, replace the printing tube and continue printing; The metal 3D printing pen includes: a pen tip (1), a medicine tube (2), and a pen tail (3); the two ends of the medicine tube (2) are respectively threaded to the pen tip (1) and the pen tail (3); the pen tip (1) is provided with a discharge port (11); the medicine tube (2) includes, from the outside to the inside: an outer shell (21), a thermal barrier coating (22), a self-propagating reactor (23), a high-temperature resistant heat-conducting layer (24), and a feeding channel (25); The thermal barrier coating (22) is made of iron elastic rare earth tantalate RETaO4, wherein RE is selected from at least one of Sc, Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb, and Lu; The self-propagating reactor (23) comprises, by weight fraction: 20.0 wt.%-45.0 wt.% Fe3O4 powder, 10.0 wt.%-40.0 wt.% CuO powder, 20.0 wt.%-25.0 wt.% Al powder, and 20.0 wt.%~30.0 wt.% diluent; the particle size of Fe3O4 powder and CuO powder is 250-300 mesh, the particle size of Al powder is 150-300 mesh, and the particle size of diluent is 400-500 mesh; The diluent is selected from one or more of wollastonite powder, silica powder, and Si3N4 powder; the material of the high-temperature resistant thermal conductive layer (24) includes one or more of SiC ceramic, Al2O3 ceramic, and Si3N4 ceramic. The pen tail (3) includes a feed inlet (31), a power assembly (32), an ignition assembly (33), and a power source (34); the power assembly (32) and the ignition assembly (33) are respectively connected to the power source (34); the power assembly (32) is used to control the continuous supply of printing material (4) from the feed inlet (31) through the feed channel (25) to the discharge outlet (11); the ignition assembly (33) is used to ignite the self-propagating reactor (23); The ignition assembly (33) includes an ignition switch (331) and a wire (332); the self-propagating reactor (23) has an ignition section (26) on the side near the pen tip (1); the electric ignition head (261) of the ignition section (26) is connected to the ignition switch (331) through the wire (332). The electric ignition head (261) of the ignition section is connected to the tail thread of the medicine tube by a wire, and the tail thread is made of conductive material; a spring contact is also provided at the internal thread of the pen tail, and the ignition switch (331) is connected in series with the spring contact by a wire.

2. The method of use according to claim 1, characterized in that, The power assembly (32) includes: a feed button (321), a motor (322), and a gear (323).

3. The method of use according to claim 1, characterized in that, The printing material (4) is selected from metal wires with a melting point of 600~1400℃.

4. The method of use according to claim 1, characterized in that, The pen tip (1) and the outer shell (21) are made of stainless steel.

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