Active metal powder drying system and method

Abstract

The invention discloses an active metal powder drying system and method, relates to the technical field of additive manufacturing, and aims to solve the problems that existing active metal powder drying is high in safety risk, and water vapor adsorbed by active metal powder cannot be effectively removed. The system comprises gas replacement equipment, powder drying equipment, heating equipment and a vacuum pump set. A plurality of layers of powder trays are fixed on a powder tray frame of the powder drying equipment, and a through hole is formed in the bottom of each powder tray; a flat scraping plate is arranged close to an opening in the upper end of each powder disc; the vacuum pump set is used for providing a vacuum environment for the gas replacement equipment; the gas inlet valve is used for filling inert gas or nitrogen, and the gas inlet valve and the exhaust valve are matched to keep the pressure in the gas replacement equipment within a preset pressure range; the leveling scraper is used for controlling the powder accumulation thickness in the powder disc; and the heating equipment is used for drying the powder. According to the active metal powder drying system, the drying safety of the active metal powder can be improved, and water vapor in the powder can be effectively removed.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a drying system and method for active metal powders. Background Art

[0002] With the development of selective laser melting (SLM) additive manufacturing technology, the types of materials are becoming increasingly rich, such as copper alloys, invar alloys, and tungsten. However, for active metals such as magnesium alloys and rare earth alloys, due to their high chemical activity, if ordinary drying methods are used for drying treatment, it will pose a great safety risk to the production safety of selective laser melting. On the other hand, for micro-selective laser melting (micro-SLM), since the powder particle size used is finer (generally 0-20 μm, and 15-53 μm for SLM), the specific surface area is larger, and the chemical activity is greater, the production and use safety risks of most metal powders are greater, which hinders the development of SLM technology and the enrichment of the material system.

[0003] In view of the above situation, the common practices in the industry are as follows: First, the powder is not dried and is directly added from the storage device to the printing device. However, during the storage of the powder, a small amount of water vapor will be adsorbed, and directly using it for printing will result in poor fluidity and spreading performance of the powder. Moreover, after a period of storage or transportation of the powder, particle size segregation will occur in the powder. Second, the powder together with the storage device is placed in an oven and evacuated for drying. However, the powder accumulates with a large thickness in the storage device, and the water vapor adsorbed by the powder at the bottom of the storage device cannot be effectively removed, resulting in poor fluidity of the powder. Summary of the Invention

[0004] The purpose of the present invention is to provide a drying system and method for active metal powders, which are used to solve the problems that the existing drying methods for active metal powders cannot effectively remove the water vapor adsorbed by the powder, and due to the high chemical activity of the active metal, the drying safety risk is large.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] In the first aspect, the present invention provides a drying system for active metal powders, including: a gas replacement device, a powder drying device, a heating device, and a vacuum pump group;

[0007] The gas replacement device includes a powder inlet, a powder outlet, an intake valve, and an exhaust valve. The heating device is installed on the inner wall of the gas replacement device, and the powder drying device is arranged inside the gas replacement device; the powder drying device includes a powder tray rack, and multiple layers of powder trays are fixed in the vertical direction of the powder tray rack. Through holes are opened at the bottom of each powder tray; a flat scraping plate is arranged at a preset height near the upper opening of each powder tray;

[0008] The vacuum pump group is connected to the gas displacement device, and the vacuum pump group is used to provide a vacuum environment for the gas displacement device; the intake valve is used to fill inert gas or nitrogen, and the intake valve and the exhaust valve cooperate to keep the pressure in the gas displacement device within a preset pressure range; the leveling scraper is used to scrape flat the to-be-dried active metal powder that falls into the powder tray and is higher than the preset height; the heating device is used to dry the to-be-dried active metal powder.

[0009] Compared with the prior art, the active metal powder drying system provided by the present invention includes: a gas displacement device, a powder drying device, a heating device, and a vacuum pump group; the gas displacement device includes a powder inlet, a powder outlet, an intake valve, and an exhaust valve. A heating device is installed on the inner wall of the gas displacement device, and a powder drying device is arranged inside the gas displacement device; the powder drying device includes a powder tray rack, and multiple powder trays are fixed in the vertical direction of the powder tray rack. Each powder tray is provided with through holes at the bottom; a leveling scraper is arranged at a preset height near the upper opening of each powder tray; the vacuum pump group is connected to the gas displacement device, and the vacuum pump group is used to provide a vacuum environment for the gas displacement device, and can reduce the oxygen content in the gas displacement device; the intake valve is used to fill inert gas or nitrogen, and the intake valve and the exhaust valve cooperate to keep the pressure in the gas displacement device within a preset pressure range, which can further reduce the oxygen content in the gas conversion device, improve operation safety, and keep a slight negative pressure inside the device, which can improve the sealing performance of the device; the provided leveling scraper can scrape flat the to-be-dried active metal powder that falls into the powder tray and is higher than the preset height, which can ensure that the thickness of the powder in the powder tray is not too thick, avoid the phenomenon that the water vapor cannot escape due to too thick powder and is easy to agglomerate, make the removal of powder water vapor more thorough. At the same time, the setting of multiple powder trays can make the powder evenly spread on the powder tray, further ensure that the water vapor in the powder is removed more thoroughly, improve the fluidity and spreadability of the powder, and can increase the amount of powder dried at one time by increasing the number and size of the powder trays, realizing the drying of a large amount of accumulated powder. By optimizing the powder drying process, adopting a vacuum pump group and introducing inert gas or nitrogen into the gas displacement device, and adding powder in a closed space and other measures, the direct contact between the active metal powder and air is avoided, and the safety of active metal drying is improved.

[0010] In a second aspect, the present invention also provides a method for drying active metal powder. The method for drying active metal powder is applied to the above-mentioned active metal powder drying system, and the active metal drying powder system includes multiple powder trays; the method includes:

[0011] Use a vacuum pump group to evacuate the air in the gas displacement device to form a vacuum environment;

[0012] Add the to-be-dried active metal powder into the gas displacement device that forms a vacuum environment; inert gas or nitrogen is filled in the gas displacement device, and the pressure is within a preset pressure range;

[0013] Use a leveling scraper to level the active metal powder to be dried that has fallen into each of the powder trays, so that the active metal powder to be dried in each powder tray is within a preset height;

[0014] Use a heating device to dry the active metal powder to be dried in each of the powder trays.

[0015] Compared with the prior art, the beneficial effects of the active metal powder drying method provided by the present invention are the same as those of the active metal powder drying system described in the above technical solution, and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 is a schematic external structure diagram of an active metal powder drying system provided by the present invention;

[0018] Figure 2 is a schematic internal structure diagram of an active metal powder drying system provided by the present invention;

[0019] Figure 3 is a schematic diagram of the powder tray included angle structure provided by the present invention;

[0020] Figure 4 is a flowchart of an active metal powder drying method provided by the present invention.

[0021] REFERENCE SIGNS:

[0022] 1 - Gas replacement device, 11 - Powder inlet, 12 - Powder outlet, 13 - Intake valve, 14 - Exhaust valve, 2 - Vacuum pump group, 3 - Powder drying device, 31 - Powder tray rack, 32 - Powder tray, 33 - Leveling scraper, 34 - Guide rail, 35 - Movable electromagnetic plug plate, 36 - Height sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] In order to clearly describe the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, terms such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and roles. For example, the first threshold and the second threshold are only used to distinguish different thresholds and do not limit their order. Those skilled in the art can understand that the terms "first" and "second" do not limit the quantity and execution order, and the terms "first" and "second" do not necessarily limit being different.

[0024] It should be noted that in the present invention, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the present invention should not be construed as being more preferred or having more advantages than other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0025] In the present invention, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after. "At least one (item)" or its similar expression refers to any combination of these items, including any combination of single item (item) or plural items (items). For example, at least one (item) of a, b or c can represent: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b and c can be single or multiple.

[0026] Reactive metals generally react violently with oxygen and react violently with dilute hydrochloric acid or dilute sulfuric acid. The existing powder drying methods cannot completely isolate the powder from the air. If the existing drying method is used to dry reactive metal powder, serious safety hazards will be generated. However, if the powder is not dried, the powder will adsorb water vapor during storage and easily agglomerate, and directly used for printing will result in poor fluidity and spreadability of the powder, affecting the printing quality of parts.

[0027] To solve the above problems, the present invention provides a reactive metal powder drying system and method, which realizes the balance between the safety of drying reactive metal powder and product performance. Next, it will be described in conjunction with the accompanying drawings.

[0028] See Figure 1 and Figure 2 , a reactive metal powder drying system provided by the present invention includes: a gas displacement device 1, a vacuum pump group 2, a powder drying device 3 and a heating device; the vacuum pump group 2 is connected to the gas displacement device 1, and the vacuum pump group 2 is used to provide a vacuum environment for the gas displacement device 1;

[0029] Such as Figure 1As shown, the gas displacement device 1 includes a powder inlet 11, a powder outlet 12, an intake valve 13, and an exhaust valve 14. The powder inlet 11 is used to add the active metal powder to be dried into the gas displacement device 1. The powder outlet 12 is used to take out the dried active metal powder. The intake valve 13 is used to fill in inert gas or nitrogen. The intake valve 13 and the exhaust valve 14 cooperate to keep the pressure inside the gas displacement device 1 within a preset pressure range. A heating device is installed on the inner wall of the gas displacement device 1, and the heating device is used to dry the active metal powder to be dried. A powder drying device 3 is arranged inside the gas displacement device 1;

[0030] As Figure 2 shown, Figure 2 in (a) of which is the front view of the powder drying device. As Figure 2 shown in (a) of which, the powder drying device 3 includes a powder tray rack 31. A plurality of powder trays 32 are fixed in the vertical direction of the powder tray rack 31. Through holes are formed at the bottoms of each powder tray 32, and the centers of the through holes are on the same vertical line, that is, the projections of the through holes on the horizontal line coincide. A movable electromagnetic baffle 35 is installed at the bottom of each powder tray 32. The movable electromagnetic baffle 35 is used to control whether the active metal powder to be dried flows out of the through hole and at the same time control the powder weight on the powder tray. A leveling scraper 33 is arranged at a preset height near the upper opening of each powder tray 32. The number of powder trays 32 is the same as the number of leveling scrapers 33. The leveling scraper 33 is connected with a moving motor, and the moving motor is fixed on the powder tray rack; Figure 2 In (b) of which is the side view of the powder drying device. As Figure 2 shown in (b) of which, the leveling scraper 33 is in a plate-like structure. The leveling scraper 33 can move horizontally in a direction perpendicular to the plate surface of the leveling scraper. The leveling scraper 33 is arranged at a preset height near the upper opening of the powder tray and is used to scrape flat the active metal powder to be dried that has fallen into the powder tray and is higher than the preset height.

[0031] The powder drying device 3 in the above structure may include one or more height sensors. As Figure 2As shown, a guide rail 34 is vertically fixed on the side wall of the powder tray rack 31. When the powder drying device 3 includes multiple height sensors 36, the height sensors 36 can be fixed on the guide rail 34 or on the leveling scraper 33. The number of height sensors 36 is the same as the number of leveling scrapers 33. The height sensors 36 are used to detect the height of the active metal powder to be dried falling into the powder tray. When the powder accumulation height reaches the preset height, the height sensor emits a signal and activates the electromagnetic baffle of the powder tray above the current powder tray to close. The leveling scraper corresponding to the current powder tray starts to move horizontally to evenly spread the powder in the powder tray. When there is one height sensor 36, the height sensor 36 is fixed on the guide rail 34 and can move vertically on the guide rail 34 with the position of the powder tray being filled with powder, and detects the height of the active metal powder to be dried falling into each powder tray by moving. It should be noted that the scheme where the height sensor is fixed on the leveling scraper Figure 2 is not shown.

[0032] See Figure 3 , in the above structure, the powder tray 32 is made of metal, and the shape of the powder tray 32 is a funnel shape. The angle α between the funnel side and the horizontal plane is greater than or equal to 30°. When the through hole is opened, the powder can naturally flow out of the powder tray. The vacuum pump group is composed of a mechanical pump or a combination of a mechanical pump and a Roots pump.

[0033] The intake valve and the exhaust valve in the above structure are both one-way valves. The intake valve only allows intake and not exhaust, and the exhaust valve only allows exhaust and not intake. Electromagnetic sensors with controllable openings are arranged at the corresponding positions of the intake valve and the exhaust valve. The electromagnetic sensors are used to automatically control the opening and closing of the intake valve and the exhaust valve. When the pressure in the gas displacement device exceeds the preset pressure range, one or both of the two valves will automatically open or close to make the pressure in the gas displacement device meet the requirements. Butterfly valves are arranged at both the powder inlet and the powder outlet. The active metal powder drying system also includes a storage tank filled with an inert gas or nitrogen, and the storage tank is used to store the dried active metal powder.

[0034] The heating device in the above structure includes a heating resistor, a temperature sensor, and a timer. The powder drying temperature is 80 - 200 °C, and the powder drying time is 4 - 24 h.

[0035] See Figure 4 , the present invention also provides a method for drying active metal powder, which is applied to the above active metal powder drying system. As Figure 4 shown, the method includes the following steps:

[0036] Step 401: Use the vacuum pump group to evacuate the air in the gas displacement device to form a vacuum environment;

[0037] Specifically, close the intake valve and exhaust valve in the gas displacement device, turn on the vacuum pump set, and discharge the residual gas or air in the gas displacement device until the absolute pressure in the gas displacement device is less than 1000 Pa. Then stop vacuum pumping and turn off the vacuum pump set to create a vacuum environment in the gas displacement device. Its function is to reduce the oxygen content in the gas displacement device. At the same time, vacuum pumping can save the time for the next inflation displacement. If the vacuum pumping step of the vacuum pump set is not carried out and only inert gas or nitrogen is filled for inflation displacement, the effect of reducing the oxygen content can also be achieved, but the time will increase.

[0038] Step 402: Add the active metal powder to be dried into the gas displacement device with a vacuum environment; the gas displacement device is filled with inert gas or nitrogen, and the pressure is within the preset pressure range;

[0039] The active metal powder to be dried needs to be sealed before drying. The powder is loaded into a storage device that has been previously filled with inert gas or nitrogen. Its function is to ensure that the powder does not come into contact with air during transfer to the storage device, improving safety.

[0040] As an optional method, before adding the active metal powder to be dried into the gas displacement device with a vacuum environment, it further includes:

[0041] Close the vacuum pump set and the valve connecting it to the gas displacement device. Fill the gas displacement device with a vacuum environment with inert gas or nitrogen through the intake valve, and discharge the gas in the gas displacement device through the exhaust valve for gas displacement. When the oxygen content in the gas displacement device is less than or equal to 1000 PPM, close the exhaust valve. When the pressure in the gas displacement device is greater than 80 kPa and less than 90 kPa, close the intake valve. Or, the vacuum pump set can be started to make the pressure in the gas displacement device reach below 500 Pa to meet the pressure requirement in the gas displacement device. Its function is to further reduce the oxygen content in the device, improve operation safety. In addition, it can maintain a slightly negative pressure in the device, improve the sealing performance of the gas displacement device, and the atmospheric pressure can press the device valves tightly.

[0042] When adding the active metal powder to be dried into the gas replacement equipment that forms a vacuum environment and has been replaced with inert gas or nitrogen, use a clamp to connect the powder outlet of the powder storage device to the powder inlet of the gas replacement equipment. Open the butterfly valve at the powder inlet of the gas replacement equipment and the butterfly valve at the powder outlet of the storage device in sequence to start adding powder. During the powder adding process, first open the electromagnetic baffle plates of all powder trays except the bottom powder tray to let the powder fall into the bottom powder tray. When the height sensor on the powder tray rack detects that the powder height reaches the preset height, close the electromagnetic baffle plate of the upper layer of the current powder tray, and then start the leveling scraper of the current layer to level the powder in the current layer, ensuring that the powder thickness is not too thick to make the removal of water vapor more thorough. Repeat the above process in the order from bottom to top to spread the powder on all powder trays at one time, and finally complete the powder adding operation.

[0043] Step 403: Use a leveling scraper to level the active metal powder to be dried that has fallen into each of the powder trays so that the active metal powder to be dried in each powder tray is within the preset height.

[0044] Specifically, monitor the height of the active metal powder to be dried that has fallen into each layer of the powder tray through a height sensor. When the height of the active metal powder to be dried reaches the preset height, close the through hole of the upper layer of the powder tray, and use the leveling scraper of the current layer to level the active metal powder to be dried in the current layer of the powder tray until the active metal powder to be dried in each powder tray is within the preset height.

[0045] Step 404: Use a heating device to dry the active metal powder to be dried in each of the powder trays.

[0046] The powder drying temperature is 80 - 200 °C, and the powder drying time is 4 - 24 h. After the drying is completed, the heating device stops heating, and inert gas or nitrogen is added to the gas replacement equipment to make the pressure in the gas replacement equipment 1 atmospheric pressure; when the dried active metal powder cools naturally to below 50 °C, the dried active metal powder is discharged through the powder outlet.

[0047] When taking out the dried active metal powder, place a storage box pre-filled with inert gas or nitrogen below the gas replacement equipment, connect the powder outlet of the gas replacement equipment and the interface of the storage box with a clamp, open the interface of the storage box and the butterfly valve at the powder outlet of the gas replacement equipment in sequence to start taking out the powder. First, open the electromagnetic baffle plate of the bottom powder tray of the powder drying equipment to let all the powder enter the storage box, and then open the electromagnetic baffle plates of the powder trays in sequence from bottom to top to let all the powder enter the storage box. After the taking out is completed, close the powder outlet of the gas replacement equipment and the interface of the storage box in sequence.

[0048] From the description of the above structure and method, it can be seen that the vacuum pump group of this drying system for active metal powder can reduce the oxygen content in the gas displacement device; the intake valve is used to fill inert gas or nitrogen, and the intake valve and the exhaust valve cooperate to keep the pressure in the gas displacement device within a preset pressure range, which can further reduce the oxygen content in the gas conversion device, improve the operation safety, and in addition, maintaining a slightly negative pressure inside the device can improve the sealing performance of the device; the set leveling scraper can scrape the active metal powder to be dried in the powder tray that is higher than the preset height, which can ensure that the powder thickness in the powder tray is not too thick, avoiding the phenomenon that the water vapor cannot escape and the powder is prone to caking when the powder is too thick, making the removal of powder water vapor more thorough. At the same time, the setting of multiple powder trays can make the powder evenly laid on the powder trays, further ensuring that the water vapor in the powder is removed more thoroughly, improving the fluidity and spreadability of the powder. By increasing the number and size of the powder trays, the quantity of powder dried at one time can be increased, improving the powder drying efficiency. By optimizing the powder drying process, adopting a vacuum pump group, introducing inert gas or nitrogen into the gas displacement device, adding powder in a closed space and other measures, the direct contact between the active metal powder and air is avoided, improving the safety of active metal drying.

[0049] In the description of the above embodiments, the specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0050] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A drying system for active metal powder, characterized in that, Including: A gas displacement device, a powder drying device, a heating device, and a vacuum pump group; The gas displacement device includes a powder inlet, a powder outlet, an intake valve, and an exhaust valve. The heating device is installed on the inner wall of the gas displacement device, and the powder drying device is arranged inside the gas displacement device; the powder drying device includes a powder tray rack, and multiple powder trays are fixed in the vertical direction of the powder tray rack. Through holes are opened at the bottom of each powder tray; a leveling scraper is arranged at a preset height near the upper opening of each powder tray; The vacuum pump group is connected to the gas displacement device, and the vacuum pump group is used to provide a vacuum environment for the gas displacement device; the intake valve is used to fill inert gas or nitrogen, and the intake valve and the exhaust valve cooperate to keep the pressure in the gas displacement device within a preset pressure range; the leveling scraper is used to scrape flat the active metal powder to be dried that falls into the powder tray and is higher than the preset height; the heating device is used to dry the active metal powder to be dried.

2. The drying system for active metal powder according to claim 1, wherein The powder tray is in a funnel shape, and the angle between the funnel side and the horizontal plane is greater than or equal to 30°. The centers of the through holes are on the same vertical line; a movable electromagnetic plug is installed at the bottom of each powder tray, and the movable electromagnetic plug is used to control whether the active metal powder to be dried flows out from the through hole; the leveling scraper is connected to a moving motor.

3. The drying system for active metal powder according to claim 1, wherein The powder drying device further includes one or more height sensors, and the height sensors are used to detect the height of the active metal powder to be dried that falls into the powder tray; when the powder drying device includes one height sensor, a guide rail is vertically fixed on the side wall of the powder tray rack, and the height sensor is fixed on the guide rail, and the height sensor moves vertically on the guide rail; when the powder drying device includes multiple height sensors, the number of height sensors is the same as the number of leveling scrapers, and the height sensors are fixed on the leveling scraper or the guide rail.

4. The drying system for active metal powder according to claim 1, wherein Both the intake valve and the exhaust valve are one-way valves, and electromagnetic sensors are arranged at the corresponding positions of the intake valve and the exhaust valve. The electromagnetic sensors are respectively used to automatically control the opening and closing of the intake valve and the exhaust valve; butterfly valves are arranged at both the powder inlet and the powder outlet. The active metal powder drying system further includes a storage tank, and the storage tank is filled with inert gas or nitrogen, and the storage tank is used to store the dried active metal powder.

5. The drying system for active metal powder according to claim 1, wherein The heating device includes a heating resistor, a temperature sensor, and a timer. The powder drying temperature is 80 - 200 °C, and the powder drying time is 4 - 24 h.

6. A method for drying active metal powder, characterized in that, The active metal powder drying method is applied to the active metal powder drying system according to any one of claims 1 - 5. The active metal powder drying system includes multiple powder trays; the method includes: Using the vacuum pump group to evacuate the air in the gas displacement device to form a vacuum environment; Adding the active metal powder to be dried into the gas displacement device that forms a vacuum environment; the gas displacement device is filled with inert gas or nitrogen, and the pressure is within a preset pressure range; Using the leveling scraper to scrape flat the active metal powder to be dried that falls into each powder tray, so that the active metal powder to be dried in each powder tray is within the preset height; A heating device is used to dry the active metal powder to be dried in each powder tray.

7. The drying method of the active metal powder according to claim 6, characterized in that, The powder drying device includes a height sensor. The step of using a flat scraper to level the active metal powder to be dried falling into each powder tray so that the active metal powder to be dried in each powder tray is within a preset height includes: Monitoring the height of the active metal powder to be dried falling into each layer of powder tray through the height sensor. When the height of the active metal powder to be dried reaches the preset height, closing the through holes of the upper layer of powder tray, and using the flat scraper of the current layer to level the active metal powder to be dried in the current layer of powder tray until the active metal powder to be dried in each powder tray is within the preset height.

8. The drying method of active metal powder according to claim 6, characterized in that, The step of using the vacuum pump group to evacuate the air in the gas replacement device to form a vacuum environment includes: Closing the inlet valve and the exhaust valve in the gas replacement device, starting the vacuum pump group, discharging the residual gas in the gas replacement device, and closing the vacuum pump group when the pressure in the gas replacement device is less than 1000 Pa, so as to form a vacuum environment in the gas replacement device.

9. The drying method of the active metal powder according to claim 6, wherein, Before adding the active metal powder to be dried into the gas replacement device that forms a vacuum environment, it also includes: Filling the gas replacement device that forms a vacuum environment with inert gas or nitrogen through the inlet valve, discharging the gas in the gas replacement device through the exhaust valve, closing the exhaust valve when the oxygen content in the gas replacement device is less than or equal to 1000 PPM, and closing the inlet valve when the pressure in the gas replacement device is greater than 80 kPa and less than 90 kPa.

10. The drying method of the active metal powder according to claim 6, characterized in that, After using the heating device to dry the active metal powder to be dried in the powder tray, it also includes: Adding inert gas or nitrogen into the gas replacement device to make the pressure in the gas replacement device 1 atmosphere; when the dried active metal powder cools naturally to below 50 °C, discharging the dried active metal powder through the powder outlet.

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