CN111962059B - Solid-state 3D printing system and method for in-orbit manufacturing and repair of space components using cold spray - Google Patents

Abstract

The invention relates to a solid-state 3D printing system and method for on-orbit manufacturing and repair of space components by using cold spraying. Send out control commands, and control the 3D mobile platform through the 3D mobile platform control chip, so that the substrate or substrate moves according to the design path, and at the same time control the valve and heater according to the data of the temperature sensor, pressure sensor and flowmeter, and adjust the process parameters. The advantage is that in the space environment, it overcomes the difficult problem that the molten 3D printing technology is difficult to combine effectively under the condition of weightlessness. In this invention, the powder has extremely high speed and accurate direction, and the kinetic energy generated by the acceleration of the gas through the Laval nozzle completely makes the metal Particles overcome the weightless environment of space.

Description

Solid-state 3D printing system for on-orbit manufacturing and repair of space components using cold spray method

technical field

The invention belongs to the technical field of space 3D printing, and relates to a solid-state 3D printing system and method for on-orbit manufacturing and repair of space components by using cold spraying. The Laval nozzle is accelerated to obtain kinetic energy and then deposited on the substrate according to the specified path to realize the manufacture or repair of metal components. The powder particles are always in a solid state during the deposition process, which is completely different from the high-energy beam 3D printing technology based on melting and solidification, so it is called solid-state 3D printing technology.

Background technique

With the development of human beings to space gradually to the far space, the spacecraft's on-orbit time and orbital altitude gradually increase. At present, the equipment required for space exploration and the parts required for routine maintenance of spacecraft still need to be transported by cargo spacecraft, which undoubtedly greatly increases the cost of space exploration. And some equipment (such as spacecraft antenna, etc.) needs to be folded before being loaded into the cargo spacecraft, which inevitably increases the difficulty of astronauts' operations. These issues are all major issues that hinder the further development of space exploration. The spacecraft itself has the manufacturing capability, which can greatly prolong the service time of the spacecraft, improve the freedom of astronauts to work in orbit, and play the role of "gas station" for the development of space exploration to deep space. How to achieve on-orbit manufacturing and repair of spacecraft in space is the key to realizing the dream of space exploration.

Parts and equipment on spacecraft are often customized rather than mass-produced, which is where 3D printing technology excels. The metal 3D printing technology of high-energy beam is to carry out computer modeling of the product, then slice the model, design the path, and then print the entity layer by layer. The metal material required for printing is fed in the form of powder or wire, heated by powder feeding or powder spreading, or melted into a liquid state in the heater before entering the nozzle, extruded from the nozzle under pressure, and deposited layer by layer, After cooling, a solid entity is formed. Due to additive manufacturing, the machining process is not affected by the structure of the part, resulting in less material waste and high accuracy. 3D printing technology is more suitable for the on-orbit manufacturing and repair of space metal components.

After recent years of development, ground 3D printing technology is becoming more and more mature. However, there is a huge difference between the space environment and the ground environment. Ground 3D printing technology cannot adapt to the special environment of space. To achieve space 3D printing, there are huge challenges in equipment, technology, materials and other aspects. For example, high temperature melting will cause alloying elements. Burning, coarse tissue, thermal stress, cracks, and the microgravity environment in space make it difficult to control the behavior of the molten pool. It is still very difficult to obtain high-performance components or repair. Therefore, exploring new metal 3D printing technologies to achieve high-quality on-orbit manufacturing and repair of metal materials is of great significance to support the service of space equipment.

SUMMARY OF THE INVENTION

technical problem to be solved

In order to avoid the deficiencies of the prior art, the present invention proposes a solid-state 3D printing system and method for on-orbit manufacturing and repair of space components by cold spraying.

One of the technical problems solved by the present invention is to provide a new metal 3D printing implementation method in a space environment, so as to realize solid-state 3D printing of on-orbit manufacturing and repair of space metal components.

The second technical problem solved by the present invention is to provide a metal 3D printing system in a space environment to realize solid-state 3D printing of on-orbit manufacturing and repair of space metal components.

The third technical problem solved by the present invention is to eliminate the metallurgical problems and slow deposition efficiency problems caused by high-temperature melting-solidification in the high-energy beam 3D printing technology, and realize the rapid and solid-state deposition of metal powders.

Technical solutions

A solid-state 3D printing system for on-orbit manufacturing and repair of space components by cold spraying is characterized by comprising a base or substrate 1, a three-dimensional mobile platform 2, a three-dimensional mobile platform control chip 3, an arc-shaped column 4, a spray gun 5, a delivery The powder metal hose 6, the working metal hose 7, the controller 8, the powder feeder 10, the hydrogen storage cylinder 11 and the supercharger 12; The path is controlled to move; the three-dimensional mobile platform 2 is rigidly fixed with the arc-shaped column 4, the arc-shaped column 4 is connected to the spray gun 5, and the powder feeding channel of the spray gun 5 is connected to the powder feeder 10 through the powder feeding metal hose 6. There is a powder feeding control valve 10-7 on the road; the working gas inlet of the spray gun 5 is connected with the hydrogen storage cylinder 11 pipeline through the supercharger 12, and a gas control valve 10-5 is installed on the pipeline; the powder feeder 10 passes through the supercharger 12 is connected to the pipeline of the hydrogen storage cylinder 11, and the pipeline is provided with a one-way control valve 10-2; the spray gun 5 includes a nozzle 5-1, a miniature temperature sensor 5-2, a distance sensor 5-3, and a temperature sensor 5-4 , pressure sensor 5-5, three-way pipe 5-6, pre-gas chamber 5-8 and built-in heater 5-9; the tail of nozzle 5-1 is provided with pre-gas chamber 5-8, The central port is connected with the three-way pipe 5-6, one channel of the three-way pipe 5-6 is connected with the powder feeder 10, and the other channel is connected with the powder feeding channel of the nozzle 5-1; the tail of the pre-air chamber 5-8 is The inlet channel of the heated hydrogen is connected with the built-in heater 5-9, and the built-in heater 5-9 is connected with the working metal hose 7; the nozzle 5-1 is provided with a micro temperature sensor 5-2, and the shell on one side is There is a distance sensor 5-3 on it, a temperature sensor 5-4 at the front of the pre-air chamber 5-8, and a pressure sensor 5-5 at the rear; the hydrogen storage cylinder includes a cylinder shell 11-1, a carbon fiber Winding layer 11-2, pure aluminum metal liner 11-3, pressure sensor 11-4, intake solenoid valve 11-6, intake manual valve 11-7, exhaust manual valve 11-9 and exhaust solenoid valve 11-10 ; The two ends of the cylinder shell 11-1 are respectively provided with an air inlet 11-12 and an air outlet 11-11, and the inner cavity is sequentially provided with a carbon fiber winding layer 11-2 and a pure aluminum metal liner 11-3; The pipeline of 11-12 is provided with a pressure sensor 11-4, an intake solenoid valve 11-6 and an intake manual valve 11-7; the pipeline of the air outlet 11-11 is provided with an exhaust manual valve 11-9 and an exhaust solenoid valve 11-10; All the data information of temperature sensor, pressure sensor, distance sensor and flowmeter are transmitted to the computer terminal, the computer terminal sends out control commands according to the three-dimensional data, and controls the three-dimensional mobile platform through the three-dimensional mobile platform control chip, so that the matrix or The substrate moves according to the designed path, while the valves and heaters are controlled based on data from temperature sensors, pressure sensing and flow meters, and process parameters are adjusted.

All valve parts are equipped with flow meters.

The nozzle 5-1 adopts a shrinking and expanding Laval nozzle, the diameter of the circular section nozzle throat is 1-3mm; the diameter of the nozzle outlet is 2.5-9mm; the downstream length of the nozzle is 100-280mm; the powder channel is located at a distance from the nozzle throat. At 10 to 30 mm from the top, the included angle with the central axis of the nozzle is 25° to 60°.

When the outlet section of the nozzle 5-1 is rectangular, the width is 1-3 mm, and the length is 5-20 mm.

The powder feeder 10 includes a powder storage chamber 10-3 and a powder feeder shell 10-4; the powder storage chamber 10-3 is provided with a plurality of through holes in the circumferential direction, and the air intake pipeline passes through the one-way valve 10-2 and the hydrogen storage bottle. 11, the powder outlet pipeline between the powder storage chamber 10-3 and the powder feeder shell 10-4 is connected to the powder feeding metal pipe 6 through the powder feeding control valve 10-7.

A method for printing a solid-state 3D printing system for on-orbit manufacturing and repair of space components by utilizing cold spraying, characterized in that the steps are as follows:

Step 1: Use computer software to model the product, and then use specific software to finely slice the model and design the printing path;

Step 2: According to the path design, the spray gun is fixed, and the three-dimensional mobile platform moves under the designed path to realize the deposition of metal particles at its specific position, so as to print components by cold spraying;

The cold spray printing process is:

Open the valve 10-5 and pass the working gas hydrogen into the heater of the spray gun for preheating. The preheating temperature is the ambient temperature of 20℃～800℃, and the pressure of the working gas hydrogen is 0.5～5MPa;

Open the one-way valve 10-2, the pressure is 0.5-5MPa, and the powder feeding gas blows the powder in the powder storage chamber 10-3 of the powder feeder.

The working gas hydrogen is transported through the pipeline to the upstream diversion section of the nozzle connected to the gun body, compressed through the contraction section, reaches the speed of sound at the throat of the nozzle, and then flows through the expansion section downstream of the nozzle to generate supersonic flow until a certain shock wave is generated at the nozzle outlet;

The powder feeding gas sends the powder out of the powder feeder, and transports the powder to the downstream expansion section of the nozzle through the pipeline. Through the powder feeding channel of the nozzle, the powder enters the downstream direction of the nozzle and the working gas flow direction at an angle of 25°~60° and the working gas in the expansion section. The temperature of the mixing and powder feeding gas is the ambient temperature of 20°C to 600°C.

The powder particles are heated in the working gas and accelerated to a high speed of 600-1600m/s along with the working gas. After flying out of the nozzle outlet, they collide with the position where the preset matrix is locked by the 3D data and deposit there. With the continuous deposition of powder, the component is manufactured.

The powder includes, but is not limited to, a mixture of one or more of pure metal, alloy, or cermet composite powder.

The particle size of the powder is 1-10 μm.

beneficial effect

The invention proposes a solid-state 3D printing system and method for on-orbit manufacturing and repair of space components by cold spraying. The data sends out control commands, and the three-dimensional mobile platform is controlled by the three-dimensional mobile platform control chip, so that the substrate or substrate moves according to the design path, and at the same time, the valve and heater are controlled according to the data of the temperature sensor, pressure sensor and flowmeter, and the process parameters are adjusted.

The features and advantages of the present invention are:

In the space environment, compared with the melting-based 3D printing technology, the invention overcomes the difficulty of effective combination of the molten 3D printing technology under the condition of weightlessness. In this invention, the powder has extremely high speed and accurate direction, and the gas passes through The kinetic energy generated by the acceleration of the Laval nozzle completely enables the metal particles to overcome the weightless environment of space.

In the space environment, compared with the molten 3D printing technology, the invention reduces the burning of elements during the printing process, and the ratio of printed components is more accurate.

In the space environment, compared with the molten 3D printing technology, the grains of the components or repaired structures produced by the invention are finer, which reduces the problem of performance degradation caused by coarse tissue.

In the space environment, compared with the molten state of 3D printing technology, because the metal particles are not melted, the heat input is smaller, and the internal thermal stress of the produced component or repaired structure is smaller.

Compared with the control method in which the substrate does not move and the nozzle moves in the molten state 3D printing technology, the present invention adopts the method in which the nozzle does not move and the substrate moves, which is more flexible. At the same time, fixing the three-dimensional mobile platform and the spray gun together eliminates the reaction force generated by the high-speed airflow particles hitting the substrate in the space environment, and improves the processing accuracy.

The nozzle adopts direct downstream powder feeding, which can avoid throat wear and prevent the downstream of the nozzle from sticking or clogging; the powder feeding port is inclined, which can reduce the downstream wear of the nozzle compared with vertical powder feeding; according to the principle of aerodynamics, the gas pressure downstream of the nozzle Sharp reduction, downstream powder feeding can avoid the use of high-pressure powder feeders, avoid complex pipeline design, reduce costs, and reduce the difficulty of powder feeding. A small heater downstream of the nozzle compensates for the heat loss of the metal powder transported in the pipe.

The shape of the nozzle is simple and the processing is convenient; if the downstream is too long, the nozzle can be processed in sections and then connected accurately.

Depending on the properties of the printing powder material, such as material strength or hardness, different gases can be used.

The invention has simple process, low production cost and good controllability.

Description of drawings

Figure 1 is a schematic diagram of a solid-state 3D printing system for on-orbit manufacturing and repair of space metal components, in the figure: 1 base or substrate, 2 3D mobile platform, 3 3D mobile platform control chip, 4 Arc-shaped column, 5 spray gun, 6 Powder feeding metal hose, 7 working metal hose, 8 control cabinet, 9 control cabinet computer terminal, 10 powder feeder, 11 hydrogen storage bottle, 12 supercharger.

Figure 2 is a schematic diagram of the structure of the spray gun, in the figure: 4-1 arc-shaped column, 4-2 arc-shaped column arc segment, 4-3 connecting bolts, 5-1 nozzle, 5-2 miniature temperature sensor, 5-3 Distance sensor, 5-4 temperature sensor, 5-5 pressure sensor, 5-6 tee pipe, 5-8 pre-air chamber, 5-9 built-in heater, 6 powder feeding metal hose, 7 spray gun working gas interface.

Figure 3 is a schematic diagram of the structure of the powder feeder: 6 powder feeding metal hose, 10-1 three-way pipe, 10-2 one-way valve, 10-3 powder storage chamber, 10-4 powder feeder shell, 10-5 control valve , 10-6 flowmeter, 10-7 control valve, 10-8 flowmeter.

Figure 4 is a schematic diagram of the structure of a hydrogen storage cylinder, in the figure: 11-1 gas cylinder shell, 11-2 carbon fiber winding layer, 11-3 pure aluminum metal liner, 11-4 pressure sensor, 11-5 flowmeter, 11-6 Solenoid valve, 11-7 manual valve, 11-8 flowmeter, 11-9 manual valve, 11-10 solenoid valve, 11-11 air outlet, 11-12 air inlet.

Fig. 5 is the accelerated addition behavior of Cu powder of Example 5-20μm

Detailed ways

The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

First, use computer software to model the product, and then use specific software to finely slice the model and design the printing path. The modeling steps can be performed on the ground or by astronauts in space.

Precisely controlled solid-state deposition of powder is performed after the path design is completed. The invention designs a three-dimensional mobile platform. During the printing process, the spray gun is fixed, and the three-dimensional mobile platform moves under the designed path to realize the deposition of metal particles at its specific position, thereby printing components. During the spraying process, the working gas is first fed into the heater for preheating, and then transported to the upstream diversion section of the nozzle connected to the gun body through the pipeline. The supersonic flow is generated through the downstream expansion section of the nozzle until a certain shock wave is generated at the nozzle outlet. The powder feeding gas takes the powder out of the powder feeder, and conveys the powder to the downstream expansion section of the nozzle through the pipeline, where it is mixed with the working gas in the expansion section. The powder is heated in the working gas and accelerates to a high speed state along with the working gas. After flying out of the nozzle outlet for a certain distance, it collides with a specific position of the preset matrix and deposits there. With the continuous deposition of the powder, the component is manufactured.

The working gas required for the solid-state 3D printing method described above is hydrogen. The preheating temperature of the working gas is the ambient temperature of 20°C to 800°C, and the pressure of the working gas is 0.5 to 5MPa. The powder feeding gas is also hydrogen; the temperature of the powder feeding gas is the ambient temperature of 20℃～600℃; the powder feeding gas pressure is 0.5～5MPa.

In the above-mentioned solid-state 3D printing method, the angle between the downstream direction of the powder input nozzle and the flow direction of the working gas (the central axis of the nozzle) is 25° to 60°.

In the above-mentioned solid-state 3D printing method, the printing powder can be pure metal, alloy, metal-ceramic composite powder, or the like. You can also choose different materials to be mixed and printed.

In the above-mentioned solid-state 3D printing method, the size of the printing particles is 1-10 μm, and the particle speed is between 600-1600 m/s.

The above-mentioned solid-state 3D printing method, through the nozzle design in the early stage and the selection of spraying process parameters, the deposition efficiency is close to 100%.

In order to successfully realize the above solid-state 3D printing method, the present invention also designs a solid-state 3D printing system for on-orbit manufacturing and repair of space components. The system includes the main control cabinet, powder feeder, gas heater, spray gun, nozzle, three-dimensional mobile platform, hydrogen storage cylinder, supercharger, connection accessories and various detection devices. The outlet of the high-pressure liquid gas cylinder is connected with the air inlet of the hydrogen storage cylinder. During operation, the liquid gas enters the hydrogen storage cylinder through the air inlet of the hydrogen storage cylinder, and the liquid gas becomes gaseous after the pressure is released. These gaseous gases enter the powder feeder through the outlet of the hydrogen storage cylinder under the action of the supercharger. The working gas enters the spray gun through the high-pressure metal copper tube; all the way becomes the powder feeding gas, enters the powder storage chamber of the powder feeder, blows the powder, and sends the powder to the powder feeding interface on the spray gun through the metal tube. After the working gas enters the spray gun, it is first heated by the built-in gas heater in the spray gun, and then it is divided into two paths again in the pre-gas chamber, one path enters the upstream of the nozzle in the spray gun, and is accelerated in the Laval nozzle; The powder feeding gas is mixed and enters the downstream of the nozzle through the powder feeding pipeline. The two paths of gas in the spray gun are mixed at a certain position downstream of the nozzle, and the powder is heated and accelerated by the working gas, and flies out of the nozzle, deposited on the designated position of the substrate, and accumulated layer by layer to form the desired part or repair.

In the above-mentioned solid-state 3D printing system for on-orbit manufacturing and repair of space metal components, the control cabinet includes a needle valve, a solenoid valve, and a flow meter to control gas flow; the pressure gauge displays the input gas pressure and the gas pressure at the gun body; The temperature display controller and thermocouple measure and control the airflow temperature at the gun body of the spray gun; the gas pipeline is connected through a metal copper pipe; the power supply is connected through a wire and controlled by a switch button. An industrial computer computer is installed in the control cabinet, and the computer is used to model, design the printing path and control the movement of the three-dimensional mobile platform.

In the above-mentioned solid-state 3D printing system for on-orbit manufacturing and repair of space metal components, the spray gun is mainly composed of a gas heater, a pre-gas chamber, and a nozzle, which are connected and fixed by threads. The heater is fixed inside the spray gun, and its interior is composed of a bent heating tube. The main gas path resistance furnace power is ~36kW (, the heating tube is stainless steel or heat-resistant steel material (such as 1Cr18Ni9Ti, 25-20 stainless steel), and the upper part of the downstream of the nozzle The power of the small heater material and the main gas circuit resistance furnace are the same as the heater material, but the interior is a strip heating tube; there are three holes above the pre-gas chamber, which are respectively connected with a three-way tube, a temperature sensor, a pressure sensor, and three The tube is connected to the powder feeding tube, the working gas enters the powder feeding tube to heat the powder, the temperature sensor records the temperature of the working gas, and the pressure sensor records the pressure of the working gas; the nozzle adopts a simple contraction and expansion type Laval nozzle; the diameter of the nozzle throat is 1~ 3mm; the diameter of the nozzle outlet is 2.5-9mm. According to the needs, the outlet can also be a rectangle with a certain cross-section, such as a width of 1-3mm and a length of 5-20mm; the downstream length of the nozzle is between 100-280mm; the distance from the nozzle throat is 10-30mm There is a powder feeding port, the angle between the powder feeding port and the airflow direction (the center axis of the nozzle) is between 25 and 60°; the powder feeding port has a joint to connect with the pipeline. In addition, there is a temperature sensor downstream of the nozzle for To detect the temperature of the gas at the nozzle, there is a distance sensor on the outer wall of the nozzle to detect the distance between the spray gun and the substrate, so as to adjust the distance in time during the printing process. The spray gun is connected to the arc-shaped column through bolts, and the arc-shaped column is connected to the three-dimensional The mobile platform is rigidly fixed.

In the above-mentioned solid-state 3D printing system for on-orbit manufacturing and repair of space metal components, the powder feeder is an inner and outer nested structure (similar to a large bucket with a small bucket, the small bucket is a powder storage room, and the large bucket is the shell of the powder feeder) Combined with one-way valve, three-way pipe, flow meter and solenoid valve for control. When working, the gas enters the powder feeder from the air inlet, and the three-way pipe divides the gas into working gas and powder feeding gas. The working gas is directly output to the powder feeder to the spray gun. The solenoid valve and flowmeter at the working gas outlet control its flow. ; The powder feeding gas enters the powder storage chamber upward, blows the powder in the powder storage chamber, and the powder in the vacuum moves irregularly under the blowing of this gas. The circumference of the powder storage chamber is covered with holes with a diameter of 1 to 1.5 mm, and between the powder storage chamber and the shell of the powder feeder is a vacuum chamber, which is called a powder feeding channel. The powder feeding gas carries the powder through the small hole into the distribution pipeline, and then converges at the outlet of the powder feeding gas and flows out of the powder feeder. The electromagnetic valve and the flow meter at the powder feeding outlet control its flow.

In the above-mentioned solid-state 3D printing system for on-orbit manufacturing and repair of space metal components, the three-dimensional mobile platform is composed of a manipulator and a control chip. The manipulator can control the substrate to move in three directions: X, Y, and Z. The manipulator is controlled by a built-in chip, which is directly connected to the computer in the control cabinet. The three-dimensional mobile platform is rigidly fixed with the arc-shaped column.

In the above-mentioned solid-state 3D printing system used for on-orbit manufacturing and repair of space metal components, the hydrogen storage cylinder is composed of three layers inside and outside, and is provided with an air inlet and an air outlet. The hydrogen storage cylinder belongs to the type III hydrogen storage cylinder. The innermost layer is a pure aluminum layer metal liner, the outermost layer is a layer of carbon fiber, and the outermost layer is a cast iron shell. The advantage of this design is that it can reduce the rapid inflation in the bottle. The resulting temperature rise enables rapid inflation. The air outlet of the gas cylinder is provided with a flowmeter, a solenoid valve and a manual valve. The flowmeter is used to detect the flow, and the solenoid valve adjusts the flow. The manual valve is a safety device, which is normally open. When the solenoid valve fails, it can be replaced. Perform flow control. The inlet design is similar to the outlet, except that a pressure sensor is added to monitor the pressure inside the bottle.

In the above-mentioned solid-state 3D printing system for on-orbit manufacturing and repair of space metal components, the supercharger is mainly composed of a motor, a rotating blade, an air inlet, and an air outlet. The hydrogen enters from the air inlet, there are grooves in the rotating blades, and the gas is circulated and pressurized in the blades to complete the gas pressurization, and finally output from the exhaust port.

In the above-mentioned solid-state 3D printing system for on-orbit manufacturing and repair of space metal components, the connecting accessories include high-pressure metal hoses and metal pipes (such as copper and stainless steel pipes).

1 , 2 , 3 and 4 , the present invention is a solid-state 3D printing method and system for on-orbit manufacturing and repair of space metal components. The manual valve 11-7 is opened during gas storage, and the manual valve 11-9 closed, the solenoid valve 11-8 is closed, the solenoid valve 11-6 and the flow meter 11-5 control the speed of the gas entering the hydrogen storage cylinder 11, the high pressure liquid gas enters the hydrogen storage cylinder 11 from the air inlet 11-12, and the gas is stored in the hydrogen storage cylinder 11. The hydrogen storage tank 11 is used in preparation for work, and the aluminum-layer metal liner of 11-3 has a good heat conduction speed, which can reduce the temperature rise during intake. When working, the manual valve 11-7 is closed, the manual valve 11-9 is opened, the solenoid valve 11-7 is closed, the gaseous high-pressure gas is output through the gas outlet of 11-11, and the solenoid valve 11-10 and the flow meter 11-8 control the gas output The speed of the hydrogen storage tank 11. The air outlet 11-11 is connected to the air inlet of the supercharger. After the gas is pressurized by the supercharger 12, it is output through the exhaust port. The exhaust port of the supercharger is connected with the three-way pipe 10-1, and the gas enters the powder feeding. 10, the gas entering the powder feeder is divided into two paths, one path is controlled by the control valve 10-5 and 10-6 flowmeter to output working gas; the other path enters the powder storage chamber 10-3 through the check valve 10-2 , carry the powder in the powder storage chamber 10-3 through the circumferential small holes of the powder storage chamber 10-3 and output the powder feeding gas to the outside according to the route of the arrow, and control the flow rate of the flow meters of the control valves 10-7 and 10-8. The working gas enters the heater 5-9 in the spray gun 5 through the working metal hose 7, and the gas is heated to 500°C to 600°C and then enters the pre-gas chamber 5-8. A part of the working gas in the pre-air chamber is accelerated to the supersonic state in the nozzle 5-1, and a part is mixed with the metal powder and the powder feeding gas in the powder feeding metal pipe 6 through the tee pipe 5-6, and the powder is heated and sent. The powder gas sends the metal powder to a confluence somewhere downstream of the nozzle 5-1, the metal powder is accelerated by the working gas, flies out of the nozzle, and is deposited on the position of the substrate 1.

The computer terminal 9 in the control cabinet 8 performs modeling and path design. After the path is designed, the data is transmitted to the three-dimensional mobile platform control chip 3, and the chip 3 controls the three-dimensional mobile platform 2 to move according to the set path.

The spray gun 5 is rigidly connected to the three-dimensional mobile platform 2, the spray gun holder column 4-1 is rigidly fixed to the three-dimensional mobile platform, and the spray gun holder arc segment 4-2 is fixed to the spray gun 5 by connecting bolts 4-3.

Implementation example:

3D printing pure Cu in space. Figure 5 shows the acceleration behavior of Cu powders of 5-20 μm. Among them: the diameter of the nozzle inlet is 20mm, the diameter of the throat is 2.7mm, the diameter of the outlet is 5.7mm, the length of the straight-through section is 20mm, the length of the contraction section is 30mm, the length of the expansion section is 170mm, the powder feeding inlet angle is 45°, and the confluence point is 20mm away from the nozzle throat; working gas It is hydrogen, the pressure is 3MPa, the temperature is 300K (room temperature); the powder feeding gas is also hydrogen, the pressure is 1.5MPa, and the temperature is 300K (room temperature). 20m/s, initial temperature 300K. After being accelerated by the nozzle, the airflow velocity is up to 3200m/s, and there is a momentary drop at the exit position (0.17m), and then rises again. The particle velocity increases rapidly after the particles enter the main air flow, and the particle velocity decreases with the increase of the particle diameter. Beyond the critical deposition rate of Cu, 100% deposition can be achieved if 5-20 μm powders are used. The highest velocity of the particles is not at the exit of the nozzle, and the velocity is still increasing after the particles fly out of the nozzle. The initial temperature of both gas and particles is 300K, and the temperature rises rapidly after being heated by the heater, reaching the highest at the nozzle throat position (0.06m), about 560K, and then gradually cooling down. During the cooling process, the larger the particle diameter, the slower the temperature drop, the slowest drop at 20μm temperature, and the fastest drop at 5μm temperature. The gas temperature reaches the lowest point at the outlet (0.17m), about 200K, and the temperature change of the particles tends to be gentle after passing through the outlet. The lowest temperature (220K) of the most 20μm particles occurs at the exit, the lowest temperature of 10μm (230K) at 0.2m, and the lowest temperature of 5μm (250K) at 0.2m.

Claims (8)

1. A solid-state 3D printing system for on-orbit manufacturing and repairing of a space component by utilizing cold spraying is characterized by comprising a base body or a base plate (1), a three-dimensional moving platform (2), a three-dimensional moving platform control chip (3), an arc-shaped upright post (4), a spray gun (5), a powder feeding metal hose (6), a working metal hose (7), a controller (8), a powder feeder (10), a hydrogen storage gas cylinder (11) and a supercharger (12); the substrate or the base plate (1) is connected with the three-dimensional moving platform, and the three-dimensional moving platform (2) moves under the control of the path of the control chip (3); the three-dimensional moving platform (2) is rigidly fixed with the arc-shaped upright post (4), the arc-shaped upright post (4) is connected with the spray gun (5), a powder inlet channel of the spray gun (5) is connected with a powder feeder (10) through a powder feeding metal hose (6) by a pipeline, and a powder feeding control valve (10-7) is arranged on the pipeline; the working gas inlet of the spray gun (5) is connected with a hydrogen storage cylinder (11) through a booster (12) by a pipeline, and a gas control valve (10-5) is arranged on the pipeline; the powder feeder (10) is connected with a hydrogen storage cylinder (11) through a booster (12) by a pipeline, and a one-way control valve (10-2) is arranged on the pipeline; the spray gun (5) comprises a nozzle (5-1), a micro temperature sensor (5-2), a distance sensor (5-3), a temperature sensor (5-4), a pressure sensor (5-5), a three-way pipe (5-6), a pre-air chamber (5-8) and a built-in heater (5-9); the tail part of the nozzle (5-1) is provided with a pre-air chamber (5-8), a middle part through port of the pre-air chamber (5-8) is connected with a three-way pipe (5-6), one channel of the three-way pipe (5-6) is connected with a powder feeder (10), and the other channel is connected with a powder feeding channel of the nozzle (5-1); the tail part of the pre-air chamber (5-8) is an inlet channel of heated hydrogen and is connected with the built-in heater (5-9), and the built-in heater (5-9) is connected with the working metal hose (7); a miniature temperature sensor (5-2) is arranged on the nozzle (5-1), a distance sensor (5-3) is arranged on the shell on one side, a temperature sensor (5-4) is arranged at the front part of the pre-air chamber (5-8), and a pressure sensor (5-5) is arranged at the rear part; the hydrogen storage cylinder comprises a cylinder shell (11-1), a carbon fiber winding layer (11-2), a pure aluminum metal inner container (11-3), a pressure sensor (11-4), an air inlet electromagnetic valve (11-6), an air inlet manual valve (11-7), an air outlet manual valve (11-9) and an air outlet electromagnetic valve (11-10); both ends of the gas cylinder shell (11-1) are respectively provided with a gas inlet (11-12) and a gas outlet (11-11), and the inner cavity is sequentially provided with a carbon fiber winding layer (11-2) and a pure aluminum metal inner container (11-3); a pipeline of the air inlet (11-12) is provided with a pressure sensor (11-4), an air inlet electromagnetic valve (11-6) and an air inlet manual valve (11-7); a pipeline of the air outlet (11-11) is provided with an air outlet manual valve (11-9) and an air outlet electromagnetic valve (11-10); and data information of all the temperature sensors, the pressure sensors, the distance sensors and the flow meters is transmitted to the computer terminal, the computer terminal sends out a control instruction according to the three-dimensional data, the three-dimensional moving platform is controlled by the three-dimensional moving platform control chip, so that the base body or the substrate moves according to a designed path, meanwhile, the valves and the heaters are controlled according to the data of the temperature sensors, the pressure sensors and the flow meters, and technological parameters are adjusted.

2. The solid state 3D printing system for in-orbit fabrication and repair of space components using cold spray as claimed in claim 1 wherein: all valve positions are provided with flow meters.

3. The solid state 3D printing system for in-orbit manufacturing and repair of space components using cold spray according to claim 1 or 2, wherein: the nozzle (5-1) adopts a contraction and expansion type Laval nozzle, and the diameter of the throat part of the nozzle with a circular section is 1-3 mm; the diameter of the outlet of the nozzle is 2.5-9 mm; the downstream length of the nozzle is 100-280 mm; the powder channel is located 10-30 mm away from the throat of the nozzle, and the included angle between the powder channel and the central axis of the nozzle is 25-60 degrees.

4. The solid state 3D printing system for in-orbit fabrication and repair of space components using cold spray of claim 3, wherein: when the section of the outlet of the nozzle (5-1) is rectangular, the width is 1-3 mm, and the length is 5-20 mm.

5. The solid state 3D printing system for in-orbit fabrication and repair of space components using cold spray according to claim 1 or 2, wherein: the powder feeder (10) comprises a powder storage chamber (10-3) and a powder feeder shell (10-4); a plurality of through holes are arranged in the circumferential direction of the powder storage chamber (10-3), an air inlet pipeline is connected with an outlet of a hydrogen storage cylinder (11) through a one-way control valve (10-2), and a powder outlet pipeline between the powder storage chamber (10-3) and a powder feeder shell (10-4) is connected with a powder feeding metal hose (6) through a powder feeding control valve (10-7).

6. A method of printing with a solid state 3D printing system for in-orbit manufacturing and repair of space components using cold spray as claimed in any of claims 1 to 5, characterized by the steps of:

step 1: modeling a product by using computer software, finely slicing the model by using specific software and designing a printing path;

step 2: according to the path design, the spray gun is fixed, and the three-dimensional moving platform moves under the designed path to realize the deposition of metal particles at the specific position, so that the component is printed by cold spraying;

the cold spraying printing process comprises the following steps:

opening a gas control valve (10-5) to introduce working gas hydrogen into a heater of the spray gun for preheating, wherein the preheating temperature is 20-800 ℃ of the ambient temperature, and the pressure of the working gas hydrogen is 0.5-5 MPa;

opening a one-way control valve (10-2) under the pressure of 0.5-5 MPa, and blowing the powder in a powder storage chamber (10-3) of the powder feeder by using powder feeding gas;

the working gas hydrogen is conveyed to a nozzle upstream flow guide section connected with a gun body through a pipeline, compressed through a contraction section, reaches the sonic speed at the throat part of the nozzle, and then generates supersonic flow through a nozzle downstream expansion section until a certain shock wave is generated at the outlet of the nozzle;

powder is sent out of the powder feeder by powder feeding gas and is conveyed to the downstream expansion section of the nozzle through a pipeline, the powder is mixed with the working gas of the expansion section through a powder feeding channel of the nozzle, the included angle between the downstream direction of the powder input nozzle and the flowing direction of the working gas is 25-60 degrees, and the temperature of the powder feeding gas is 20-600 ℃ of the ambient temperature;

the powder particles are heated in the working gas, accelerated to a high speed state of 600-1600 m/s along with the working gas, collided at the position where the preset matrix is locked by the three-dimensional data after flying out of the outlet of the nozzle, and deposited, and the component is manufactured along with the continuous deposition of the powder.

7. The method of claim 6, wherein: such powders include, but are not limited to: one or more of pure metal, alloy or cermet composite powder.

8. The method of claim 7, wherein: the particle size of the powder is 1 to 10 μm.

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