Magnesium alloy laser selective melting manufacturing device and manufacturing method

Abstract

The application belongs to the technical field of additive manufacturing, and discloses a magnesium alloy laser selective melting manufacturing device and a manufacturing method, wherein the device comprises a forming cavity, an atmosphere protection system and a pressurizing assembly; the forming cavity is provided with an air inlet and an air outlet; the atmosphere protection system comprises a gas storage tank, an air inlet pipeline and an air outlet pipeline; the pressurizing assembly comprises a pressure increasing valve and a pressure reducing valve; the pressure increasing valve is arranged on the air inlet pipeline; and the pressure reducing valve is arranged on the air outlet pipeline; the pressure increasing valve is used for inputting inert gas into the forming cavity at a first pressure; and the pressure reducing valve is used for outputting the gas in the forming cavity at a second pressure, so that the pressure in the forming cavity is kept at a preset pressure and a gas flow is formed in the forming cavity; and the preset pressure is greater than the atmospheric pressure. The pressure in the forming cavity is increased through the adjustable pressure increasing valve and pressure reducing valve, a high-pressure environment in the forming cavity can be kept, the boiling point of magnesium is increased by increasing the pressure in the forming cavity, and the purpose of expanding the printable parameter window of the magnesium alloy is achieved.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, and more specifically, relates to a magnesium alloy laser selective melting manufacturing equipment and manufacturing method. Background Technology

[0002] With the increasing demands for comprehensive product performance in critical sectors such as aerospace equipment and weapon manufacturing, lightweight component design concepts, such as flow channels and topologies, are beginning to be applied to magnesium alloy parts. However, current magnesium alloy forming primarily employs traditional casting and plastic forming processes, which struggle to process the internal components of integrated parts, limiting the potential of magnesium alloys to leverage their lightweight advantages and construct intricate flow channel or topological structures. In recent years, laser selective melting technology has emerged, overcoming the limitations of traditional manufacturing principles and offering advantages such as high precision, high design freedom, and high raw material utilization. By adjusting process parameters, the microstructure and properties of the alloy can be controlled, maximizing the form-property synergistic design capabilities of the alloy material, thereby achieving near-net-shape forming of complex structural products that are impossible with traditional manufacturing methods.

[0003] However, the difference between the melting point (649℃) and boiling point (1090℃) of magnesium is only 441℃, which easily leads to violent evaporation of magnesium alloys during selective laser melting (SLM), causing problems such as severe powder splashing and partial loss of the formed part. This limits the use of parameter combinations with relatively low laser energy density when forming magnesium alloys using SLM. Samples printed with these parameter combinations are prone to defects such as porosity and unmelted voids, restricting the development and application of lightweight, defect-free, and high-strength magnesium alloys produced by SLM.

[0004] Currently, the mainstream approach is to find process parameters within a narrow window that allow for the use of higher laser input energy without evaporating the magnesium alloy. This can be achieved by appropriately reducing the dynamic viscosity of the molten metal to ensure sufficient diffusion, reduce powder splashing, improve interlayer wettability, and decrease porosity in the component. However, given the narrow process parameter window for selective laser melting of magnesium alloys, finding suitable process parameters inevitably requires significant time and resources. Therefore, the primary challenge in overcoming the limitations of selective laser melting of magnesium alloys is to expand the suitable process parameter window, enabling the use of higher laser input energy without causing severe evaporation of the magnesium alloy. Summary of the Invention

[0005] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a magnesium alloy laser selective melting manufacturing equipment and manufacturing method. Its purpose is to increase the boiling point of magnesium by increasing the pressure of the forming chamber, thereby solving the problems of narrow printing parameter window and violent magnesium evaporation in the magnesium alloy laser selective melting forming process.

[0006] To achieve the above objectives, according to one aspect of the present invention, a magnesium alloy laser selective melting manufacturing apparatus is provided, comprising a forming cavity, an atmosphere protection system, and a pressurizing assembly. The forming cavity is provided with an inlet and an outlet. The atmosphere protection system includes a gas storage tank, an inlet pipeline, and an outlet pipeline. The gas storage tank stores inert gas. The gas storage tank is connected to the inlet through the inlet pipeline, and the outlet is connected to the outlet pipeline. The pressurizing assembly includes a pressure boosting valve and a pressure reducing valve. The pressure boosting valve is located on the inlet pipeline, and the pressure reducing valve is located on the outlet pipeline.

[0007] During the process of manufacturing a workpiece in the forming cavity, the pressure boosting valve is used to input inert gas into the forming cavity at a first pressure, and the pressure reducing valve is used to output the gas inside the forming cavity at a second pressure, wherein the first pressure is greater than the second pressure, so that the pressure inside the forming cavity is maintained at a preset pressure and an airflow is formed inside the forming cavity from the air inlet to the air outlet to carry away the powder inside the cavity, wherein the preset pressure is greater than atmospheric pressure.

[0008] According to the magnesium alloy laser selective melting manufacturing equipment provided by the present invention, the forming cavity is provided with a cavity oxygen detector and a plurality of cavity pressure sensors. The plurality of cavity pressure sensors are distributed in different parts of the forming cavity. The cavity oxygen detector and the cavity pressure sensors are respectively connected to a signal processor. The signal processor is connected to a control component. The control component is respectively connected to the pressure boosting valve and the pressure reducing valve.

[0009] According to the magnesium alloy laser selective melting manufacturing equipment provided by the present invention, the gas outlet pipeline is further provided with a filter and an oxygen purifier, the filter and the oxygen purifier are sequentially connected to the outlet of the pressure reducing valve, and the outlet of the oxygen purifier is connected to the gas storage tank.

[0010] According to the magnesium alloy laser selective melting manufacturing equipment provided by the present invention, a filter pressure sensor and a filter oxygen detector are connected to the outlet of the filter, an intake blower is provided on the intake pipe, and an outlet blower is provided on the outlet pipe.

[0011] The magnesium alloy laser selective melting manufacturing equipment provided by the present invention further includes a first branch, a first electric valve is provided between the pressure reducing valve and the filter, one end of the first branch is connected between the pressure reducing valve and the first electric valve, the other end of the first branch is connected to the outlet of the filter, and a second electric valve is provided on the first branch.

[0012] The magnesium alloy laser selective melting manufacturing equipment provided by the present invention further includes a second branch, wherein a third electric valve is provided at the inlet of the oxygen purifier, a fourth electric valve is provided at the outlet of the oxygen purifier, one end of the second branch is connected to the inlet of the third electric valve, the other end of the second branch is connected to the outlet of the fourth electric valve, and a fifth electric valve is provided on the second branch.

[0013] According to the magnesium alloy laser selective melting manufacturing equipment provided by the present invention, a purified oxygen detector and a first exhaust pipe are provided between the outlet of the oxygen purifier and the fourth electric valve, and a sixth electric valve is provided on the first exhaust pipe.

[0014] The magnesium alloy laser selective melting manufacturing equipment provided by the present invention further includes a gas cylinder, a second exhaust pipe, a tank pressure sensor and a tank oxygen detector. The gas cylinder is connected to the gas storage tank, the gas storage tank is connected to the second exhaust pipe, and the gas storage tank is equipped with the tank pressure sensor and the tank oxygen detector.

[0015] According to another aspect of the present invention, a method for manufacturing magnesium alloys by laser selective melting is provided, based on the magnesium alloy laser selective melting manufacturing equipment described in any one of the preceding claims, the manufacturing method comprising:

[0016] Before the forming cavity manufactures the workpiece, an inert gas is introduced into the forming cavity to expel the air inside the forming cavity and to increase the gas pressure inside the forming cavity to a preset pressure.

[0017] During the process of manufacturing a workpiece in the forming cavity, the flow rate of the inert gas inside the forming cavity is controlled by controlling the pressure boosting valve and the pressure reducing valve, so that the pressure inside the forming cavity is maintained at a preset pressure and an airflow is formed inside the forming cavity from the air inlet to the air outlet to carry away the powder inside the cavity.

[0018] According to the magnesium alloy laser selective melting manufacturing method provided by the present invention, an inert gas is introduced into the forming cavity to purge the air inside the forming cavity, specifically including:

[0019] Inert gas is introduced into the gas storage tank to purge the air inside the tank;

[0020] Inert gas is introduced into the forming cavity through the gas storage tank to expel the air inside the forming cavity.

[0021] In summary, compared with the prior art, the magnesium alloy laser selective melting manufacturing equipment and method provided by this invention offer the following advantages:

[0022] 1. A pressure boosting valve is installed at the air inlet of the forming cavity, and a pressure reducing valve is installed at the air outlet of the forming cavity. The pressure inside the forming cavity is increased by the adjustable pressure boosting valve and pressure reducing valve, which can control the oxygen concentration inside the forming cavity at a low level and maintain a high-pressure environment inside the forming cavity. By increasing the pressure inside the forming cavity, the boiling point of magnesium is increased, thereby expanding the printable parameter window of magnesium alloy. This is beneficial for manufacturing with a larger laser input energy and helps to avoid the violent evaporation of magnesium alloy. At the same time, the pressure boosting component does not affect the gas flow inside the forming cavity and also helps the airflow to carry away the cavity powder in time, thus ensuring manufacturing quality.

[0023] 2. The manufacturing equipment and method combine gas filtration and deoxygenation processes. The filter adsorbs magnesium vapor in the blown gas, and the oxygen purifier removes oxygen from the blown gas, thus achieving the recycling of inert gas and greatly reducing the waste of inert gas resources.

[0024] 3. The atmosphere protection system in this manufacturing equipment is equipped with multiple branches, which makes the gas flow direction more diverse and can better adapt to different airflow processes, thus improving manufacturing efficiency. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the magnesium alloy laser selective melting manufacturing equipment provided by the present invention;

[0026] Figure 2 This is a schematic diagram of the pressure boosting valve provided by the present invention;

[0027] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0028] 1-Gas cylinder pressure reducing valve, 2-Intake blower, 3-Pressure booster valve, 4-Forming cavity, 5-Cavity pressure sensor, 6-Cavity pressure sensor, 7-Cavity oxygen detector, 8-Signal processor, 9-Cavity pressure reducing valve, 10-First electric valve, 11-Second electric valve, 12-Activated carbon filter, 13-Filter pressure sensor, 14-Filter oxygen detector, 15-Outlet blower, 16-Fifth electric valve, 17-Third electric valve, 18-Oxygen purifier, 19-Heater, 20-Purified oxygen detector, 21-Integrated control unit, 22- Gas storage tank, 23-Inlet check valve, 24-Return check valve, 25-Tank pressure sensor, 26-Fourth electric valve, 27-Sixth electric valve, 28-First exhaust port, 29-Tank oxygen detector, 30-Exhaust check valve, 31-Second exhaust port, 32-Pressure regulating valve, 33-Drive chamber A, 34-Drive chamber B, 35-Pressure boosting chamber B, 36-Pressure boosting chamber A, 37-Piston, 38-Pressure boosting inlet check valve, 39-Reversing valve, 40-Pressure boosting inlet, 41-Pressure boosting inlet check valve, 42-Pressure boosting outlet check valve, 43-Pressure boosting outlet check valve. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0030] Please see Figure 1 This invention provides a magnesium alloy laser selective melting manufacturing equipment. The manufacturing equipment includes a forming cavity 4, an atmosphere protection system, and a pressurizing component. The forming cavity 4 is provided with an air inlet and an air outlet. The atmosphere protection system includes a gas storage tank 22, an air inlet pipeline, and an air outlet pipeline. The gas storage tank 22 stores inert gas. The gas storage tank 22 is connected to the air inlet through the air inlet pipeline, and the air outlet is connected to the air outlet pipeline. The pressurizing component includes a pressure boosting valve 3 and a pressure reducing valve. The pressure boosting valve 3 is located on the air inlet pipeline, and the pressure reducing valve is located on the air outlet pipeline.

[0031] During the manufacturing process of the workpiece in the forming cavity 4, the pressure boosting valve 3 is used to input inert gas into the forming cavity 4 at a first pressure, and the pressure reducing valve is used to output the gas inside the forming cavity 4 at a second pressure, wherein the first pressure is greater than the second pressure, so that the pressure inside the forming cavity 4 is maintained at a preset pressure and an airflow is formed inside the forming cavity 4 from the air inlet to the air outlet to carry away the powder inside the cavity, wherein the preset pressure is greater than atmospheric pressure.

[0032] Forming cavity 4 is used for manufacturing magnesium alloy workpieces, specifically, the magnesium alloy workpieces are manufactured using laser selective melting within forming cavity 4. Forming cavity 4 has an air inlet and an air outlet, both connected to an atmosphere protection system to form an inert atmosphere circulation. The atmosphere protection system connects to an inert gas source and forming cavity 4 to maintain a low-oxygen environment within the printing chamber (forming cavity 4) to prevent workpiece oxidation and deterioration that could affect manufacturing quality. The pressurization assembly includes a pressure boosting valve 3 and a pressure reducing valve (cavity pressure reducing valve 9), which control the air inlet flow rate of the atmosphere protection system and the air outlet flow rate of forming cavity 4, respectively. The pressurization assembly pressurizes the forming cavity 4, ensuring normal gas circulation while maintaining the pressure within forming cavity 4 at a set value.

[0033] The magnesium alloy laser selective melting manufacturing equipment provided by this invention is equipped with a pressure boosting valve 3 at the air inlet of the forming cavity 4 and a pressure reducing valve at the air outlet of the forming cavity 4. By adjusting the pressure boosting valve 3 and the pressure reducing valve, the pressure in the forming cavity 4 is increased, which can control the oxygen concentration in the forming cavity 4 at a low level and maintain a high-pressure environment in the forming cavity 4. By increasing the pressure in the forming cavity 4, the boiling point of magnesium is increased, thereby expanding the printable parameter window of the magnesium alloy. This is beneficial for manufacturing with a larger laser input energy and helps to avoid the violent evaporation of magnesium alloy. At the same time, the pressure boosting component does not affect the gas flow in the forming cavity 4 and also helps the airflow to carry away the cavity powder in time, thereby ensuring the manufacturing quality.

[0034] Furthermore, the forming cavity 4 is provided with a cavity oxygen detector 7 and a plurality of cavity pressure sensors 5. The plurality of cavity pressure sensors 5 are distributed in different parts of the forming cavity 4. The cavity oxygen detector 7 and the cavity pressure sensors 5 are respectively connected to a signal processor 8. The signal processor 8 is connected to a control component. The control component is respectively connected to the pressure boosting valve 3 and the pressure reducing valve.

[0035] refer to Figure 1 In this embodiment, the forming cavity 4 may be equipped with a cavity oxygen detector 7 and two cavity pressure sensors, namely cavity pressure sensor 5 and cavity pressure sensor 6. The cavity pressure sensors 5 and 6 may be distributed on both sides of the forming cavity 4, for example, one near the air inlet and the other near the air outlet. The cavity oxygen detector 7 is used to detect the oxygen concentration in the cavity in real time to ensure that the oxygen concentration in the cavity is below a preset concentration. The cavity pressure sensor 5 is used to detect the pressure in the cavity in real time to ensure that the pressure in the cavity is maintained at a preset pressure. Each sensor can send the detection signal to the signal processor 8. The signal processor 8 compares the detection signal with a preset value and then sends the judgment result to the control component. The control component generates control commands based on the judgment result to control the operation of the pressure boosting valve 3 and the pressure reducing valve accordingly.

[0036] Furthermore, when multiple cavity pressure sensors 5 are set, the average value of the multiple cavity pressure sensors 5 can be taken as the real-time pressure value in the forming cavity 4. The specific number and location of the cavity pressure sensors 5 are not limited.

[0037] Specifically, refer to Figure 2 The booster valve 3 has a built-in pressure regulating valve 32 that can be controlled by a pressure sensor. The pressure regulating valve 32 can control the output pressure. The booster valve 3 includes a pressure regulating valve 32, a reversing valve 39, two drive chambers and two booster chambers. The booster valve 3 is located on the pipeline between the gas storage tank 22 and the air inlet of the forming cavity 4. The cavity pressure sensor 5 in the forming cavity 4 can feed back the real-time pressure in the forming cavity 4 to the pressure regulating valve 32 in the booster valve 3. The pressure regulating valve 32 can control the real-time pressure of the gas. The pressure reducing valve is located on the pipeline connected to the air outlet of the forming cavity 4 to ensure smooth flow of gas in the cavity.

[0038] The preset pressure value in the forming cavity 4 is set. When the cavity pressure sensor 5 reports that the air pressure is lower than the preset pressure value, the pressure boosting valve 3 works to force the gas in the gas storage tank 22 into the forming cavity 4. Once the set value is reached, the work stops immediately. The pressure reducing valve equipped at the air outlet of the forming cavity 4 reduces the high pressure gas in the cavity to a suitable pressure and discharges the gas evenly. The combination of the two achieves the purpose of pressurizing the forming cavity 4 to the set pressure value and ensuring smooth circulation of inert gas.

[0039] Furthermore, the outlet pipe is also equipped with a filter and an oxygen purifier 18, which are sequentially connected to the outlet of the pressure reducing valve. The outlet of the oxygen purifier 18 is connected to the gas storage tank 22. The filter and oxygen purifier 18 simultaneously adsorb magnesium vapor from the gas blown out of the forming cavity 4 and purify the oxygen in the gas, allowing the gas to re-enter the gas circulation and significantly reducing the consumption of inert gas.

[0040] Furthermore, the atmosphere protection system includes at least a filter, an oxygen purifier 18, and a gas storage tank 22. The filter inlet is connected to the outlet of the forming chamber 4, and a pressure reducing valve is sequentially connected in between. The pressure reducing valve inlet is connected to the outlet of the forming chamber 4, and the pressure reducing valve outlet is connected to the filter. The filter outlet is connected to the oxygen purifier 18, and the gas storage tank 22 is connected to the outlet of the oxygen purifier 18. The gas storage tank 22 is used to store compressed inert gas, such as argon, in the system for pressurization of the chamber by the pressurization component. At the same time, the gas purified by the atmosphere protection system can be stored in the system, so that the gas can re-enter the gas circulation, which is equivalent to the function of a "reservoir" and a "buffer tank".

[0041] Optionally, the filter may include an activated carbon filter screen 12; the control component may be an integrated control unit 21. The air inlet and outlet of the forming chamber 4 may be positioned opposite each other above the powder bed, and the gas at the air inlet can blow magnesium vapor to the side of the air outlet, causing it to be blown out of the forming chamber 4 through the pipe and into the filter screen.

[0042] Furthermore, a filter pressure sensor 13 and a filter oxygen detector 14 are connected to the outlet of the filter, an intake blower 2 is provided on the intake pipe, and an outlet blower 15 is provided on the outlet pipe.

[0043] A filtered oxygen detector 14 and a filtered pressure sensor 13 are installed after the filter to monitor the oxygen concentration and pressure of the filtered gas. The filtered pressure sensor 13 and the filtered oxygen detector 14 can be connected to the signal processor 8, respectively. The intake blower 2 and the exhaust blower 15 can be connected to the control components, respectively. During the manufacturing process of magnesium alloy workpieces, one blower can be turned on first, for example, the intake blower 2, to drive the gas flow. When the pressure detection value is too low, a signal is fed back to the signal processor 8. After processing, the signal processor 8 sends a command to the integrated control unit 21. The control unit performs an emergency stop on the equipment and issues an alarm at the same time, indicating that the filter screen is clogged. If the pressure is too high, the processor sends a command to the control unit, and another blower, such as the exhaust blower 15, starts to work to accelerate the airflow.

[0044] When the oxygen concentration detected by the oxygen filter detector 14 meets the standard, that is, when it is lower than the preset concentration value, the oxygen purifier 18 can be turned off and the filtered gas can flow directly into the gas storage tank 22; when the oxygen concentration detected does not meet the standard, that is, when it is higher than the preset concentration value, the oxygen purifier 18 can be turned on to purify and absorb the oxygen before discharging it into the gas storage tank 22.

[0045] Optionally, two blowers are provided, both controlled by an integrated control unit 21; the filter screen inside the filter has a multi-layer structure, which can adsorb magnesium vapor onto the filter screen; the oxygen purifier 18 includes a heater 19 and multiple layers of copper mesh. The heater 19 can be arranged in a ring, and the copper mesh has multiple layers, which are parallel to each other and placed inside the ring heater 19, and are evenly distributed among the copper meshes. The mesh size of the copper mesh is 200-300 mesh; heating by the heater 19 can raise the temperature of the copper mesh, which can react quickly with oxygen to remove oxygen. The heater 19 is used to heat the copper mesh, and the specific shape and positional relationship of the heater 19 and the copper mesh can also be other, with the aim of better heating the copper mesh, and are not specifically limited.

[0046] Furthermore, the magnesium alloy laser selective melting manufacturing equipment also includes a first branch, with a first electric valve 10 disposed between the pressure reducing valve and the filter. One end of the first branch is connected between the pressure reducing valve and the first electric valve 10, and the other end of the first branch is connected to the outlet of the filter. A second electric valve 11 is disposed on the first branch. The first electric valve 10 and the second electric valve 11 can be respectively connected to a control assembly. The on / off state of the first branch can be controlled by controlling the opening and closing of the first electric valve 10 and the second electric valve 11, so that the airflow at the outlet can selectively pass through the filter.

[0047] Furthermore, the magnesium alloy laser selective melting manufacturing equipment also includes a second branch. A third electric valve 17 is provided at the inlet of the oxygen purifier 18, and a fourth electric valve 26 is provided at the outlet of the oxygen purifier 18. One end of the second branch is connected to the inlet of the third electric valve 17, and the other end is connected to the outlet of the fourth electric valve 26. A fifth electric valve 16 is provided on the second branch. The third electric valve 17, the fourth electric valve 26, and the fifth electric valve 16 can be connected to a control assembly. The opening and closing of the third electric valve 17, the fourth electric valve 26, and the fifth electric valve 16 can control the on / off state of the second branch, allowing the airflow at the outlet to selectively pass through the oxygen purifier 18.

[0048] Setting up a first branch and a second branch makes the gas flow direction of the atmosphere protection system more diverse, better adaptable to different airflow processes, and conducive to improving manufacturing efficiency.

[0049] Furthermore, a purified oxygen detector 20 is provided between the outlet of the oxygen purifier 18 and the fourth electric valve 26, and a first exhaust pipe is connected thereto. A sixth electric valve 27 is provided on the first exhaust pipe. With the first exhaust pipe and purified oxygen detector 20 in place, when the oxygen concentration detected by the purified oxygen detector 20 is below standard, the first exhaust pipe can be opened to discharge the gas flowing from the outlet. Alternatively, before workpiece manufacturing, when venting oxygen from the forming cavity 4, the first exhaust pipe can be opened to discharge the gas flowing from the outlet.

[0050] Furthermore, the magnesium alloy laser selective melting manufacturing equipment also includes a gas cylinder, a second exhaust pipe, a tank pressure sensor 25, and a tank oxygen detector 29. The gas cylinder is connected to the gas storage tank 22, which is connected to the second exhaust pipe. The gas storage tank 22 is equipped with the tank pressure sensor 25 and the tank oxygen detector 29. Before workpiece manufacturing, to expel oxygen from the gas storage tank 22, the forming chamber 4 can be closed, and the second exhaust pipe can be opened to directly expel the air from the gas storage tank 22.

[0051] The gas cylinder is a high-pressure gas cylinder, which can be connected to the gas storage tank 22 via the gas cylinder pressure reducing valve 1 to supply gas to the gas storage tank 22. The gas storage tank 22 is equipped with a tank pressure sensor 25 and a tank oxygen detector 29, which are respectively connected to the signal processor 8; when the gas pressure detected by the tank pressure sensor 25 reaches the set value, it prompts to shut down the gas cylinder.

[0052] Furthermore, the intake pipe is also equipped with an intake one-way valve 23; the pipe between the oxygen purifier 18 and the gas storage tank 22 is also equipped with a return one-way valve 24; and the second exhaust pipe is also equipped with an exhaust one-way valve 30. Both the outlet and inlet of the gas storage tank 22 are equipped with one-way valves, ensuring that the gas can only flow in one direction.

[0053] Furthermore, a magnesium alloy laser selective melting manufacturing equipment also includes a laser forming system, which includes a laser, a galvanometer, a forming cavity 4, a substrate, etc. The specific setup and operation process of the laser forming system are well known to those skilled in the art and will not be described in detail here.

[0054] Furthermore, the present invention also provides a method for manufacturing magnesium alloys by laser selective melting, based on the magnesium alloy laser selective melting manufacturing equipment described in any of the above embodiments, wherein the manufacturing method includes:

[0055] Before the forming cavity 4 manufactures the workpiece, an inert gas is introduced into the forming cavity 4 to expel the air inside the forming cavity 4, and the gas pressure inside the forming cavity 4 is increased to a preset pressure.

[0056] During the manufacturing process of the workpiece in the forming cavity 4, the flow rate of the inert gas inside the forming cavity 4 is controlled by the pressure boosting valve 3 and the pressure reducing valve, so that the pressure inside the forming cavity 4 is maintained at a preset pressure and an airflow is formed inside the forming cavity 4 from the air inlet to the air outlet to carry away the powder inside the cavity.

[0057] Furthermore, introducing an inert gas into the forming cavity 4 to expel the air inside the forming cavity 4 specifically includes:

[0058] Inert gas is introduced into the gas storage tank 22 to purge the air inside the gas storage tank 22;

[0059] Inert gas is introduced into the forming cavity 4 through the gas storage tank 22 to expel the air inside the forming cavity 4.

[0060] Introducing inert gas into the gas storage tank 22 to purge the air inside the gas storage tank 22 specifically includes:

[0061] Close the forming cavity 4 to make the forming cavity 4 a sealed space, open the second exhaust pipe, and introduce inert gas into the gas storage tank 22.

[0062] When the oxygen concentration detected by the oxygen detector 29 in the tank reaches the standard, the second exhaust pipe is shut off;

[0063] When the pressure value detected by the tank pressure sensor 25 reaches the standard, the introduction of inert gas into the gas storage tank 22 is stopped.

[0064] Inert gas is introduced into the forming cavity 4 through the gas storage tank 22 to expel the air inside the forming cavity 4, specifically including:

[0065] Open the first branch of the air inlet pipe, the first exhaust pipe, and close the oxygen purifier 18. Inert gas is introduced into the forming cavity 4 through the air outlet tank to discharge the air inside the forming cavity 4.

[0066] This increases the gas pressure inside the forming cavity 4 to a preset pressure, specifically including:

[0067] When the oxygen concentration detected by the cavity oxygen detector 7 meets the standard, close the outlet of the forming cavity 4, open the inlet pipe, and introduce inert gas into the forming cavity 4.

[0068] Until the pressure value detected by the cavity pressure sensor 5 reaches the preset pressure.

[0069] After the gas pressure inside the forming cavity 4 increases to the preset pressure, the workpiece manufacturing begins in the forming cavity 4.

[0070] Specifically, refer to Figure 1 The diagram shows the pressurization process of the forming cavity 4 in the additive manufacturing system of the present invention. The pressurization process of the forming cavity 4 is mainly divided into two steps. First, inert gas is introduced to replace the air in the forming cavity 4 and reduce the oxygen concentration in the cavity. Second, the cavity pressure is set and the forming cavity 4 is pressurized through the pressure boosting valve 3. After the pressurization is completed, laser printing is performed.

[0071] The first step is as follows: First, complete the preliminary preparations, then close the forming cavity 4 to make it a sealed space. Next, close the inlet one-way valve 23 and the return one-way valve 24, and open the exhaust one-way valve 30. Then, open the compressed argon cylinder to fill the storage tank 22 with argon gas and expel the air from the storage tank 22. When the oxygen content in the storage tank 22 drops to a certain value, close the exhaust one-way valve 30, open the inlet one-way valve 23, close the first electric valve 10, the fifth electric valve 16, and the fourth electric valve 26, and open the second electric valve 11, the third electric valve 17, and the sixth electric valve 27, as well as the inlet blower 2. At this time, the argon gas flows rapidly into the forming cavity 4 through the blower, quickly replacing the air in the forming cavity 4. The flowing gas in the exhaust cavity will flow along the pipe. The oxygen purifier 18 does not need to be turned on, and the gas does not need to be treated by the filter and the oxygen purifier 18. It is directly discharged through the first exhaust port 28.

[0072] After argon gas is introduced for a period of time, when the oxygen detector 7 in the forming cavity 4 detects that the oxygen concentration is lower than the designed oxygen concentration in the printable cavity, the second electric valve 11, the third electric valve 17, and the sixth electric valve 27 are closed, and the first electric valve 10, the fifth electric valve 16, and the return gas check valve 24 are opened. At this time, argon gas flows into the gas storage tank 22 through the return gas check valve 24 and begins to enter the internal gas circulation. The tank pressure sensor 25 and the tank oxygen detector 29 in the gas storage tank 22 provide real-time feedback on the gas status in the gas storage tank 22, thereby transmitting the information to the signal processor 8 to control the flow rate of compressed argon gas into the gas storage tank 22, so as to achieve orderly circulation of argon gas.

[0073] The second process: Set the gas pressure inside the forming chamber 4, i.e., the preset pressure, open the pressure boosting valve 3, and close the pressure reducing valve after forming chamber 4. At this time, the two chamber pressure sensors 5 inside forming chamber 4 begin to report the real-time gas pressure inside forming chamber 4 to the signal processor 8. The signal processor 8 transmits this signal to the integrated control unit 21, which then begins to control the pressure regulating valve 32 in the pressure boosting valve 3 and the air intake blower 2. A large amount of argon gas is sent to the pressure boosting valve 3 by the air intake blower 2. (Reference) Figure 2 Argon gas input from the intake blower 2 enters the pressure regulating valve 32 through the booster inlet 40, and then splits into two paths. One path opens the booster inlet check valves 38 and 41 to fill the booster chambers A36 and B35 of the small cylinder. The other path passes through the pressure regulating valve 32 and the reversing valve 39 to the drive chamber B34 of the large cylinder. At the same time, the drive chamber A33 exhausts gas, the large piston 37 moves to the left, and the small piston 37 also moves to the left, boosting the pressure in chamber B of the small cylinder. The booster outlet check valve 43 opens and high-pressure gas is sent out from the outlet. When the small piston 37 reaches its end, the reversing valve 39 switches, so that the drive chamber A33 intakes gas, the drive chamber B34 exhausts gas, the large piston 37 moves in the opposite direction, the booster chamber A36 is boosted, the booster outlet check valve 42 opens, and high-pressure gas continues to be sent out from the output port; this can automatically maintain the outlet pressure at a certain value.

[0074] The booster valve 3 can achieve any set outlet pressure within the boost ratio range. If the outlet feedback pressure of the booster valve 3 balances the spring force of the pressure regulating valve 32, the booster valve 3 will stop operating and no longer output flow. The outlet pressure value of the booster valve 3 can be set to be the same as the preset pressure of the forming chamber 4. When the pressure inside the forming chamber 4 reaches the preset pressure, the booster valve 3 will stop working. The preset pressure inside the forming chamber 4 can be greater than or equal to 10 atmospheres.

[0075] When the pressure inside the forming chamber 4 reaches the preset pressure, the laser forming system begins printing the sample. Simultaneously, the chamber pressure reducing valve 9 is opened, the fifth electric valve 16 is closed, the fourth electric valve 26 is opened, the third electric valve 17 is opened, and the heater 19 inside the oxygen purifier 18 is activated. At this time, the high-pressure gas inside the forming chamber 4 is blown out, carrying away the magnesium vapor evaporated during printing. Subsequently, as the flowing gas passes through the filter screen, the magnesium vapor is adsorbed onto the activated carbon filter screen. The heater 19 inside the purifier starts working at the beginning of printing. The annular heater 19 can uniformly heat the multi-layered thin copper mesh to above 400℃. When the gas flows through the oxygen purifier 18, the heated thin copper mesh increases the contact area with the gas. Simultaneously, the high temperature of up to 400℃ causes the thin copper mesh to rapidly react with the oxygen in the argon gas, achieving the purpose of removing trace amounts of oxygen from the argon gas. The deoxygenated argon gas flows into the gas storage tank 22 through a one-way valve, re-entering the inert gas circulation.

[0076] The pressurization scheme conceived in this invention:

[0077] This pressurization method increases the pressure in the forming cavity 4 through the adjustable pressure boosting valve 3 and pressure reducing valve, without affecting the gas flow in the forming cavity 4. Its advantage is that it can maintain the high pressure environment in the forming cavity 4 while keeping the oxygen concentration at a low level, thereby expanding the window of printable parameters for magnesium alloys.

[0078] Traditional laser selective melting equipment can only increase the pressure in the forming cavity 4 to 2-3 atmospheres, which does not have a significant impact on the boiling point of magnesium alloys. This invention can achieve higher pressure in the forming cavity 4 by adjusting the outlet pressure of the pressure boosting valve 3, providing more printing parameter options.

[0079] This pressurization method combines gas filtration and deoxygenation processes. Magnesium vapor in the blown-out gas is adsorbed by the activated carbon filter 12, and the trace amount of oxygen in the inert gas argon is reacted by the heated copper mesh, thus achieving the recycling of inert gas and greatly reducing the waste of inert gas resources.

[0080] The present invention will be further described in detail below with reference to specific examples.

[0081] Specific Example 1

[0082] Centrifugally atomized Mg-15 Gd-1 Zn-0.4Zr (GZ151K, wt.%) magnesium alloy spherical powder was used, with a particle size of 15-53 μm. The alloy powder contained 13.57% Gd, 0.85% Zn, and 0.3% Zr, with the remainder being magnesium. Before printing, the magnesium alloy powder was baked in an oven for 30-35 minutes (oven temperature 150°C). Then, the powder was poured into the powder feeding cylinder, and the corresponding substrate was placed on the bottom plate of forming cavity 4. The cavity door of forming cavity 4 was closed to form a sealed space. The pressurization process then consisted of two steps: the first step was to replace the air in the entire system, reducing the oxygen content to meet the oxygen concentration standard for printing; the second step was to issue commands to the pressure boosting valve 3 and other components through the control unit to pressurize the forming cavity 4.

[0083] Furthermore, in the atmosphere protection system workflow, the compressed argon cylinder is first opened, and the introduced argon gas will continuously replace the air in the gas storage tank 22. Once the replacement is completed, the gas storage tank 22 will become an inert gas source for replacing the air in the forming cavity 4 and the pipeline. The replaced air and argon gas are continuously discharged through the exhaust port until the oxygen concentration in the forming cavity 4 drops to the range within which the laser printing system can operate.

[0084] The complete workflow is as follows: Open the exhaust check valve 30, close the inlet check valve 23 and the return check valve 24, open the compressed argon cylinder, adjust the parameters of the cylinder pressure reducing valve 1, and argon gas continuously flows into the storage tank 22 to replace the air; when the oxygen detector 29 in the storage tank 22 reports that the oxygen concentration has dropped to the set value, close the exhaust check valve 30 at the second exhaust port 31, close the first electric valve 10, the fifth electric valve 16, and the fourth electric valve 26, open the inlet check valve 23 and the inlet blower 2, and open the second electric valve 11, the third electric valve 17, and the sixth electric valve 27. At this time, the pressure boosting valve 3 is not working, and the argon gas in the gas storage tank 22 will be introduced into the forming cavity 4. The air in the forming cavity 4 is discharged and flows along the pipeline. It does not need to be processed by the filter screen and oxygen purifier 18. Finally, it is directly discharged through the first exhaust port 28. That is, the airflow in this stage is gas cylinder pressure reducing valve 1—gas storage tank 22—exhaust one-way valve 30—second exhaust port 31 and gas cylinder pressure reducing valve 1—gas storage tank 22—intake one-way valve 23—intake blower 2—forming cavity 4—cavity pressure reducing valve 9—second electric valve 11—third electric valve 17—sixth electric valve 27—first exhaust port 28.

[0085] Once the oxygen concentration in the forming cavity 4 reaches the standard, the cavity oxygen detector 7 in the forming cavity 4 sends a signal to the signal processor 8. The signal processor 8 then issues an instruction to the control unit to close the cavity pressure reducing valve 9, open the pressure boosting valve 3 and the air intake blower 2 to pressurize the forming cavity 4. When the pressure value detected by the cavity pressure sensor 5 reaches the preset pressure, the cavity pressure reducing valve 9, the first electric valve 10 and the fourth electric valve 26 are opened, the second electric valve 11 and the sixth electric valve 27 are closed, and the return gas check valve 24 is opened. At this time, the atmosphere protection system and the laser forming system are connected in the gas path. The gas path is as follows: gas cylinder pressure reducing valve 1—gas storage tank 22—air intake check valve 23—air intake blower 2—forming cavity 4—cavity pressure reducing valve 9—first electric valve 10—activated carbon filter 12—third electric valve 17—fourth electric valve 26—return gas check valve 24—gas storage tank 22.

[0086] Furthermore, in the pressurization process, the target pressure for forming cavity 4 is set to 10 atmospheres according to the characteristics of magnesium alloy material. The pressure boosting valve 3, cavity pressure reducing valve 9, and heater 19 are opened, and the outlet pressure of the pressure reducing valve is set to be slightly greater than one atmosphere. At this time, the air intake blower 2 continuously blows the argon gas circulating in the gas storage tank 22 into the inlet of the pressure boosting valve 3. The input argon gas is divided into two paths. One path opens the pressure boosting inlet check valve 38 and pressure boosting inlet check valve 41 to fill the pressure boosting chambers A36 and B35 of the small cylinder. The other path is sent to the drive chamber B34 of the large cylinder through the pressure regulating valve 32 and the reversing valve 39. At the same time, the drive chamber A33 exhausts, the large piston 37 moves to the left, which drives the small piston 37 to also move to the left. The small cylinder B chamber is pressurized, and the pressure boosting outlet check valve 43 is opened to send high-pressure gas out from the outlet. When the small piston 37 reaches its end, the reversing valve 39 switches, causing air to enter the drive chamber A33 and exhaust from the drive chamber B34. The large piston 37 moves in the opposite direction, pressurizing the pressure chamber A36 and opening the pressure outlet check valve 42 to continue sending high-pressure gas from the output port. If the gas pressure in the forming chamber 4 is lower than 10 atmospheres, the pressure valve 3 will continue to work to pressurize the gas. The outlet pressure of the pressure valve 3 can be set to 10 atmospheres. When the gas pressure in the forming chamber 4 reaches 10 atmospheres, the pressure valve 3 will stop working.

[0087] The outlet of forming cavity 4 is connected to cavity pressure reducing valve 9, allowing the high-pressure gas in forming cavity 4 to flow out smoothly. The air inlet in forming cavity 4 can blow the evaporated magnesium vapor into the air outlet, and then through the air outlet into the activated carbon filter screen 12. The filter screen can adsorb magnesium vapor and purify the gas. The gas that has undergone preliminary purification flows smoothly into oxygen purifier 18. At this time, heater 19 has heated the multi-layer 200-mesh copper mesh to above 400°C. The gas flowing through it comes into contact with the 200-mesh copper mesh and reacts instantly, reacting the trace oxygen in the circulating gas to achieve the purpose of deoxygenation, purifying the gas once again. The purified gas flows into the gas storage tank 22 through a one-way valve and re-enters the gas circulation.

[0088] Through the pressurization process described above, the pressure inside the forming cavity 4 can be increased to the requirements of the material, and the inert gas can be recycled, which not only expands the process parameter window of magnesium alloy, but also saves gas resources. Finally, under the laser additive manufacturing process with a larger process parameter window, the printing of magnesium alloy parts is completed.

[0089] Specific Example 2

[0090] AZ91 D alloy powder, a magnesium alloy spherical powder, is atomized using spherical gas. The powder particle size is 53-75 μm. The alloy powder contains 9.08% Al, 0.65% Zn, and 0.23% Mn, with the remainder being magnesium. Before printing, the magnesium alloy powder is baked in an oven for 30-35 minutes (oven temperature 150°C). Then, the powder is poured into the powder feeding cylinder, and the corresponding substrate is placed on the bottom plate of forming cavity 4. The cavity door of forming cavity 4 is then closed to form a sealed space. The pressurization process is divided into two steps: the first step is to replace the air in the entire system, reducing the oxygen content to meet the oxygen concentration standard for printing; the second step is to issue commands to the pressure boosting valve 3 and other components through the control unit to pressurize the forming cavity 4.

[0091] Furthermore, in the atmosphere protection system workflow, the compressed argon cylinder is first opened, and the introduced argon gas will continuously replace the air in the gas storage tank 22. Once the replacement is completed, the gas storage tank 22 will become an inert gas source for replacing the air in the forming cavity 4 and the pipeline. The replaced air and argon gas are continuously discharged through the exhaust port until the oxygen concentration in the forming cavity 4 drops to the range within which the laser printing system can operate.

[0092] The complete workflow is as follows: Open the exhaust check valve 30, close the inlet check valve 23 and the return check valve 24, open the compressed argon cylinder, adjust the parameters of the cylinder pressure reducing valve 1, and argon gas continuously flows into the storage tank 22 to replace the air. When the oxygen detector 29 in the storage tank 22 reports that the oxygen concentration has decreased to the set value, close the exhaust check valve 30 at the second exhaust port 31, close the first electric valve 10, the fifth electric valve 16, and the fourth electric valve 26, open the inlet check valve 23 and the inlet blower 2, and open the second electric valve 11, the third electric valve 17, and the sixth electric valve 27. At this time, the pressure boosting valve 3 is not working, and the argon gas in the gas storage tank 22 will be introduced into the forming cavity 4. The air in the forming cavity 4 is discharged and flows along the pipeline. It does not need to be processed by the filter screen and oxygen purifier 18. Finally, it is directly discharged through the first exhaust port 28. That is, the airflow in this stage is gas cylinder pressure reducing valve 1—gas storage tank 22—exhaust one-way valve 30—second exhaust port 31 and gas cylinder pressure reducing valve 1—gas storage tank 22—intake one-way valve 23—intake blower 2—forming cavity 4—cavity pressure reducing valve 9—second electric valve 11—third electric valve 17—sixth electric valve 27—first exhaust port 28.

[0093] Once the oxygen concentration in the forming cavity 4 reaches the standard, the cavity oxygen detector 7 in the forming cavity 4 sends a signal to the signal processor 8. The signal processor 8 then issues an instruction to the control unit to close the cavity pressure reducing valve 9, open the pressure boosting valve 3 and the air intake blower 2 to pressurize the forming cavity 4. When the pressure value detected by the cavity pressure sensor 5 reaches the preset pressure, the cavity pressure reducing valve 9, the first electric valve 10 and the fourth electric valve 26 are opened, the second electric valve 11 and the sixth electric valve 27 are closed, and the return gas check valve 24 is opened. At this time, the atmosphere protection system and the laser forming system are connected in the gas path. The gas path is as follows: gas cylinder pressure reducing valve 1—gas storage tank 22—air intake check valve 23—air intake blower 2—forming cavity 4—cavity pressure reducing valve 9—first electric valve 10—activated carbon filter 12—third electric valve 17—fourth electric valve 26—return gas check valve 24—gas storage tank 22.

[0094] Furthermore, in the pressurization process, the target pressure for forming cavity 4 is set to 10 atmospheres according to the characteristics of magnesium alloy material. The pressure boosting valve 3, cavity pressure reducing valve 9, and heater 19 are opened, and the outlet pressure of the pressure reducing valve is set to be slightly greater than one atmosphere. At this time, the air intake blower 2 continuously blows the argon gas circulating in the gas storage tank 22 into the inlet of the pressure boosting valve 3. The input argon gas is divided into two paths. One path opens the pressure boosting inlet check valve 38 and pressure boosting inlet check valve 41 to fill the pressure boosting chambers A36 and B35 of the small cylinder. The other path is sent to the drive chamber B34 of the large cylinder through the pressure regulating valve 32 and the reversing valve 39. At the same time, the drive chamber A33 exhausts, the large piston 37 moves to the left, which drives the small piston 37 to also move to the left. The small cylinder B chamber is pressurized, and the pressure boosting outlet check valve 43 is opened to send high-pressure gas out from the outlet. When the small piston 37 reaches its end, the reversing valve 39 switches, causing air to enter the drive chamber A33 and exhaust from the drive chamber B34. The large piston 37 moves in the opposite direction, pressurizing the pressure chamber A36 and opening the pressure outlet check valve 42 to continue sending high-pressure gas from the output port. If the gas pressure in the forming chamber 4 is lower than 10 atmospheres, the pressure valve 3 will continue to work to pressurize the gas. The outlet pressure of the pressure valve 3 can be set to 10 atmospheres. When the gas pressure in the forming chamber 4 reaches 10 atmospheres, the pressure valve 3 will stop working.

[0095] The outlet of forming cavity 4 is connected to cavity pressure reducing valve 9, allowing the high-pressure gas in forming cavity 4 to flow out smoothly. The air inlet in forming cavity 4 can blow the evaporated magnesium vapor into the air outlet, and then through the air outlet into the activated carbon filter screen 12. The filter screen can adsorb magnesium vapor and purify the gas. The gas that has undergone preliminary purification flows smoothly into oxygen purifier 18. At this time, heater 19 has heated the multi-layer 200-mesh copper mesh to above 400°C. The gas flowing through it comes into contact with the 200-mesh copper mesh and reacts instantly, reacting the trace oxygen in the circulating gas to achieve the purpose of deoxygenation, purifying the gas once again. The purified gas flows into the gas storage tank 22 through a one-way valve and re-enters the gas circulation.

[0096] Through the pressurization process described above, the pressure inside the forming cavity 4 can be increased to the requirements of the material, and the inert gas can be recycled, which not only expands the process parameter window of magnesium alloy, but also saves gas resources. Finally, under the laser additive manufacturing process with a larger process parameter window, the printing of magnesium alloy parts is completed.

[0097] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for manufacturing magnesium alloys by laser selective melting, characterized in that, The magnesium alloy laser selective melting manufacturing equipment includes a forming cavity, an atmosphere protection system, and a pressurizing assembly. The forming cavity has an inlet and an outlet. The atmosphere protection system includes a gas storage tank, an inlet pipeline, and an outlet pipeline. The gas storage tank stores inert gas and is connected to the inlet via the inlet pipeline. The outlet is connected to the outlet pipeline. The pressurizing assembly includes a pressure boosting valve and a pressure reducing valve. The pressure boosting valve is located on the inlet pipeline, and the pressure reducing valve is located on the outlet pipeline. The pressurizing assembly is used to pressurize the forming cavity, ensuring normal gas circulation when the pressure within the forming cavity is maintained at a set value. The outlet pipe is also equipped with a filter and an oxygen purifier. The filter and the oxygen purifier are connected in sequence to the outlet of the pressure reducing valve, and the outlet of the oxygen purifier is connected to the gas storage tank. It also includes a first branch, wherein a first electric valve is provided between the pressure reducing valve and the filter, one end of the first branch is connected between the pressure reducing valve and the first electric valve, the other end of the first branch is connected to the outlet of the filter, and a second electric valve is provided on the first branch; It also includes a second branch, a third electric valve at the inlet of the oxygen purifier, a fourth electric valve at the outlet of the oxygen purifier, one end of the second branch is connected to the inlet of the third electric valve, the other end of the second branch is connected to the outlet of the fourth electric valve, and a fifth electric valve is provided on the second branch. A purified oxygen detector and a first exhaust pipe are also provided between the outlet of the oxygen purifier and the fourth electric valve. A sixth electric valve is provided on the first exhaust pipe. The manufacturing method includes: Before the forming cavity manufactures the workpiece, an inert gas is introduced into the forming cavity to expel the air inside the forming cavity and to increase the gas pressure inside the forming cavity to a preset pressure. During the process of manufacturing a workpiece in the forming cavity, the pressure boosting valve is used to input inert gas into the forming cavity at a first pressure, and the pressure reducing valve is used to output the gas inside the forming cavity at a second pressure, wherein the first pressure is greater than the second pressure. By controlling the pressure boosting valve and the pressure reducing valve, the flow rate of the inert gas inside the forming cavity is controlled, so that the pressure inside the forming cavity is maintained at a preset pressure and an airflow is formed inside the forming cavity from the air inlet to the air outlet to carry away the powder inside the cavity. The oxygen purifier includes a heater; the preset pressure inside the forming cavity is greater than or equal to 10 atmospheres; during the pressurization process, the pressure boosting valve, pressure reducing valve, and heater are opened, and the outlet pressure of the pressure reducing valve is set to be slightly greater than one atmosphere; by increasing the pressure inside the forming cavity, the boiling point of magnesium is increased, thereby expanding the printable parameter window of the magnesium alloy.

2. The method for manufacturing magnesium alloy by laser selective melting as described in claim 1, characterized in that, The forming cavity is equipped with a cavity oxygen detector and multiple cavity pressure sensors. The multiple cavity pressure sensors are distributed in different parts of the forming cavity. The cavity oxygen detector and the cavity pressure sensors are respectively connected to a signal processor. The signal processor is connected to a control component. The control component is respectively connected to the pressure boosting valve and the pressure reducing valve.

3. The method for manufacturing magnesium alloy by laser selective melting as described in claim 1, characterized in that, The filter outlet is connected to a filter pressure sensor and a filter oxygen detector. An intake blower is installed on the intake pipe, and an outlet blower is installed on the outlet pipe.

4. The method for manufacturing magnesium alloy by laser selective melting as described in claim 1, characterized in that, It also includes a gas cylinder, a second exhaust pipe, a tank pressure sensor, and a tank oxygen detector. The gas cylinder is connected to the gas storage tank, the gas storage tank is connected to the second exhaust pipe, and the gas storage tank is equipped with the tank pressure sensor and the tank oxygen detector.

5. The method for manufacturing magnesium alloy by laser selective melting as described in claim 1, characterized in that, Introducing an inert gas into the forming cavity to purge the air inside the forming cavity specifically includes: Inert gas is introduced into the gas storage tank to purge the air inside the tank; Inert gas is introduced into the forming cavity through the gas storage tank to expel the air inside the forming cavity.

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