Powder supply system for metal 3D printing and control method thereof

Abstract

A metal 3D printing powder supply system and its control method. The system comprises a remote monitoring and control device, a powder supply mechanism and a powder feeding tank, the powder supply mechanism comprises a box body, a man-machine interaction device, a controller, a powder storage tank and a circulating system, a powder feeding pipeline is installed below the filter element of the powder feeding tank, a first material level sensor is installed on the powder feeding tank, and an air outlet pipeline is installed above the filter element of the powder feeding tank; the circulating system comprises a fan, a powder feeding pipeline and an air return pipeline, the powder feeding pipeline and the air return pipeline are connected to the fan and the powder feeding tank through a connecting pipeline; a powder outlet pipeline is installed at the powder outlet of the powder storage tank, the installation position of the powder outlet pipeline and the powder feeding pipeline is inclined, so that the powder outlet direction and the powder feeding direction of the powder feeding pipeline form an acute angle, a first butterfly valve is installed on the powder outlet pipeline, a second material level sensor is installed on the powder storage tank, and the controller controls the working state of each component. The problems of powder blockage, uneven delivery and the like in the powder conveying process at present are solved, thereby affecting the printing quality and efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of additive manufacturing, in particular to a powder supply system for metal 3D printing and a control method thereof. BACKGROUND

[0002] Metal powder is the core material of 3D printing, and its types are constantly enriched, including aluminum alloy, copper alloy, titanium alloy, etc. Each material has its unique performance and application scenario. Generally, the preparation and performance requirements of metal powder are high, therefore, how to ensure safety, reduce pollution, reduce loss and improve efficiency during transportation is a problem to be solved at present.

[0003] In the aspect of powder supply system for metal 3D printing, the conventional means used in the past is relatively limited. Some systems use simple gravity powder feeding method, that is, relying on the gravity of the powder itself to transport from the powder tank to the forming chamber. Some systems use mechanical stirring powder feeding, which makes the powder fall uniformly through the stirring device. However, these methods often need frequent manual intervention during operation, such as manual powder addition, adjusting the powder feeding speed, etc. Moreover, there is a lack of effective monitoring and adjusting means for the storage and transportation environment of the powder. In summary, it is difficult to ensure stable supply of powder during powder transportation at present, and problems such as powder blockage and uneven transportation are prone to occur, which affects the printing quality and efficiency. SUMMARY

[0004] The present application provides a powder supply system for metal 3D printing and a control method thereof, which solves the problem that it is difficult to ensure stable supply of powder during powder transportation at present, and problems such as powder blockage and uneven transportation are prone to occur, which affects the printing quality and efficiency.

[0005] In the first aspect of the present application, a powder supply system for metal 3D printing is provided, which adopts the following technical scheme:

[0006] A metal 3D printing powder supply system, the system comprises a remote monitoring device, a powder supply mechanism and at least one powder tank with filter element, the powder supply mechanism comprises a box, a man-machine interaction device arranged on the box and a controller arranged in the box, a powder storage tank and a circulating system, the lower powder port of the powder tank is communicated with the forming chamber, the upper tank powder inlet is arranged on the sidewall below the filter element, the powder inlet pipeline is installed at the upper tank powder inlet opening, the first material level sensor is installed below the upper tank powder inlet, the upper tank air return opening is arranged above the filter element, and the air outlet pipeline is installed at the upper tank air return opening; the circulating system comprises a fan, a powder feeding pipeline and an air return pipeline, one end of the powder feeding pipeline is installed at the fan air outlet, the other end of the powder feeding pipeline is fixedly connected with the free end of the powder feeding pipeline, one end of the air return pipeline is installed at the fan air return, and the other end of the air return pipeline is fixedly connected with the free end of the air outlet pipeline; the air return pipeline, the air outlet pipeline and the powder feeding pipeline and the powder feeding pipeline are fixedly connected through the connecting pipeline; the powder outlet of the powder storage tank is provided with a powder outlet pipeline, and the installation position of the powder outlet pipeline and the powder feeding pipeline is inclined; the inclination of the powder outlet pipeline makes the included angle between the powder feeding direction and the powder feeding direction formed by the air flow generated by the fan be an acute angle; the powder outlet pipeline is provided with a first butterfly valve, the powder storage tank is provided with a second material level sensor, the first material level sensor is electrically connected with the remote monitoring device, the remote monitoring device is in communication connection with the controller, the second material level sensor, the first butterfly valve and the fan are electrically connected with the controller, and universal wheels are further installed at the bottom of the box.

[0007] By adopting the technical scheme, unmanned and automatic continuous powder feeding is realized, the problems of limited powder storage capacity of the powder feeding structure of the large metal 3D printing equipment and low and unsafe efficiency of manual climbing powder feeding are solved; the operator only needs to touch a button such as'start powder feeding' on the man-machine interaction device to start powder feeding, the powder feeding process is automatically controlled by the controller, manual operation is avoided, the powder feeding efficiency is improved, and the safety of the staff is ensured; the installation positions of the powder outlet pipeline and the powder feeding pipeline are inclined, and the included angle between the powder outlet direction and the powder feeding direction is an acute angle, which helps the powder to smoothly enter the powder feeding pipeline, prevents the powder from being blocked, and reduces the mechanical design cost; the first material level sensor detects the powder material level in the powder feeding tank in real time, the current powder state in the powder feeding tank is obtained in real time, the second material level sensor can monitor the powder material level in the powder feeding tank in real time, and the powder feeding control is realized by ensuring that sufficient powder is always stored in the powder storage tank; the powder feeding tank serves as a transfer structure between the powder storage tank and the forming chamber, a pressure buffer unit is formed between the powder storage tank and the forming chamber, direct transmission of pressure changes in the powder storage tank to the forming chamber is avoided, powder spouting, splashing or interruption of conveying caused by sudden pressure changes is reduced, a sealed circulation system is formed between the powder storage tank, the powder feeding tank and the forming chamber, an inert gas atmosphere closed-loop powder feeding is formed, the metal powder is protected from the external environment, the powder feeding efficiency and the equipment stability and service life are improved; at the same time, the universal wheels at the bottom of the box body facilitate the movement of the controller, the powder storage tank and the circulation system and other equipment installed in the box body, and the powder feeding pipeline of the circulation system, the powder inlet pipeline of the powder feeding tank and the air outlet pipeline of the powder feeding tank are fixedly connected through the connecting pipelines, so that the circulation system can adapt to multiple powder feeding tanks, the powder feeding of multiple powder feeding tanks is realized, and the powder feeding of multiple forming chambers is realized, which can adapt to the forming chambers that need to use the same kind of metal powder for 3D printing, and can also adapt to the forming chambers that need to use different kinds of metal powder for 3D printing; and the control and data acquisition of the powder feeding tank are realized through the remote measurement and control device, the remote measurement and control device can realize the control and data transmission of multiple powder feeding tanks, that is, after the controller and the remote measurement and control device are communicatively connected, the controller issues instructions to the remote measurement and control device to realize the control and data acquisition of the powder feeding tank, so as to establish a connection with multiple powder feeding tanks and realize the powder feeding of multiple forming chambers.

[0008] Optionally, the powder storage tank, the powder feeding pipeline and the air return pipeline are each provided with a pressure balance pipeline for communication with the external environment, the pressure balance pipeline is provided with a pinch valve, and the pinch valve is electrically connected with the controller; the air outlet pipeline and the powder inlet pipeline are each provided with a second butterfly valve, and the second butterfly valve is electrically connected with the remote measurement and control device.

[0009] By adopting the technical scheme, the pressure balance pipeline and the pinch valve in communication with the external environment are installed on the powder storage tank, the powder feeding pipeline and the return air pipeline, so that the pressure of the system and the external environment can be effectively balanced to prevent the powder from being transported due to excessive pressure difference; the pinch valve is electrically connected to the controller for control, so that automatic pressure balance adjustment can be realized. The second butterfly valve is installed on the air outlet pipeline and the powder inlet pipeline and electrically connected to the remote measurement and control device, so that the second butterfly valve can be controlled by the remote measurement and control device, the circulation of the gas and the powder can be flexibly adjusted, the stability and reliability of the system are improved, and automatic pipeline cleaning can be realized to reduce the powder blockage phenomenon.

[0010] Optionally, the box body is further provided with an inertization control device electrically connected to the controller, the box body is provided with an inert gas inlet, the inert gas inlet is in communication with the inertization control device, the powder feeding pipeline is provided with a gas washing inlet, the return air pipeline is provided with a gas washing outlet in communication with an external filtering device, the inertization control device is in communication with the gas washing inlet, the upper powder tank is provided with an oxygen content detector and a temperature detection sensor, the upper powder tank is provided with a pressure sensor and a pressure relief valve, and the oxygen content detector, the temperature detection sensor, the pressure sensor and the pressure relief valve are electrically connected to the remote measurement and control device.

[0011] By adopting the technical scheme, the box body is further provided with an inertization control device electrically connected to the controller, the box body is provided with an inert gas inlet, the inert gas inlet is in communication with the inertization control device, the powder feeding pipeline is provided with a gas washing inlet, the return air pipeline is provided with a gas washing outlet in communication with an external filtering device, the inertization control device is in communication with the gas washing inlet, the upper powder tank is provided with an oxygen content detector and a temperature detection sensor, the upper powder tank is provided with a pressure sensor and a pressure relief valve, and the oxygen content detector, the temperature detection sensor, the pressure sensor and the pressure relief valve are electrically connected to the remote measurement and control device.

[0012] Optionally, the first material level sensor comprises a high material level sensor and a low material level sensor, the low material level sensor is close to the lower powder outlet of the upper powder tank, the high material level sensor is close to the powder inlet of the upper tank, and the box body is further provided with an alarm device electrically connected to the controller.

[0013] By adopting the technical scheme, the first material level sensor is provided with a high material level sensor and a low material level sensor, the low material level sensor is close to the powder outlet of the upper powder tank, and the high material level sensor is close to the powder inlet of the upper tank, so that the material level of the powder in the upper powder tank can be more accurately detected, accurate data can be provided for powder feeding control, automatic powder feeding circulation can be realized, the high material level sensor is installed below and close to the powder inlet of the upper tank, so that the phenomenon of backflow caused by the powder in the upper powder tank overflowing the powder inlet of the upper tank can be avoided, the low material level sensor is installed close to the powder outlet of the upper powder tank, which indicates that the material level in the upper powder tank is low at present, and the powder needs to be added in time, and the man-machine interaction device and the alarm device electrically connected with the controller are installed on the box body, so that the working personnel can clearly understand the state of each unit of the powder feeding system, problems can be found and solved in time, and industrial efficiency is improved.

[0014] Optionally, the filter element of the upper powder tank is provided with a differential pressure detector for detecting the differential pressure of two ends of the filter element, the differential pressure detector is electrically connected with the remote measurement and control device, the upper powder tank is provided with a back-blowing gas bag above the filter element, the back-blowing gas bag is communicated with the inside of the upper powder tank through a blowing pipeline, the gas outlet end of the blowing pipeline is arranged in the upstream area of the filter element airflow channel in the inside of the upper powder tank, a back-blowing pulse valve is arranged on the blowing pipeline, and the back-blowing pulse valve is electrically connected with the controller to control the opening and closing of the back-blowing pulse valve through the controller.

[0015] By adopting the technical scheme, the differential pressure detector can detect the differential pressure of two ends of the filter element of the upper powder tank and feed data back to the remote measurement and control device, when the differential pressure of the filter element is detected to be abnormal, the controller can control the back-blowing pulse valve to be opened, so that the back-blowing gas bag releases gas to the upstream area of the filter element airflow channel through the blowing pipeline to perform back-blowing, clean the powder accumulated on the filter element, solve the filter element blockage problem, ensure smooth powder feeding, thereby improving the powder feeding efficiency, and at the same time maintaining the pressure balance in the upper powder tank to ensure the stable operation of the entire powder supply system.

[0016] Optionally, a manual butterfly valve is further installed on the powder outlet pipeline.

[0017] By adopting the technical scheme, the opening and closing of the lower powder pipeline can be manually controlled, manual intervention and adjustment of the powder supply can be facilitated when necessary, and the flexibility of system operation is enhanced.

[0018] In a second aspect of the present application, a control method of a metal 3D printing powder supply system is provided, adopting the following technical scheme:

[0019] A control method of a safety treatment system for additive manufacturing, applied to the system of the first aspect, the method comprises:

[0020] In response to a powder feeding request, the second butterfly valve is opened;

[0021] acquire a current state of a second material level sensor based on the powder feeding request, and determine whether a powder remaining amount in the current powder storage tank meets a powder feeding requirement based on the current state of the second material level sensor;

[0022] If it is determined that the powder remaining amount in the current powder storage tank is equal to or lower than a preset minimum material level based on the current state of the second material level sensor, a powder supplement signal is generated, and an alarm device is controlled to issue an alarm to prompt an operator to supplement powder;

[0023] The current oxygen content data detected by the oxygen content detection sensor is acquired based on the powder feeding request, and it is determined whether the current oxygen content of the current powder feeding tank, the powder feeding pipeline and the return air pipeline is lower than a preset safety threshold based on the current oxygen content data;

[0024] If it is determined that the current oxygen content of the current powder feeding tank, the powder feeding pipeline and the return air pipeline is higher than or equal to the preset safety threshold based on the current oxygen content data, a gas washing instruction is generated, and a gas washing control device and a second butterfly valve are controlled to be opened;

[0025] When the current oxygen content data detected by the oxygen content detection sensor determines that the current oxygen content of the current powder feeding tank, the powder feeding pipeline and the return air pipeline is lower than the preset safety threshold, a gas washing stop instruction is generated, and the gas washing control device is controlled to be closed;

[0026] When the powder remaining amount in the powder storage tank meets the powder feeding requirement and the current oxygen content is lower than the preset safety threshold, the fan, the first butterfly valve and the second butterfly valve are controlled to be opened, and the first butterfly valve is opened after a first preset time period, so that the fan feeds the powder into the powder feeding tank;

[0027] In response to a stop powder feeding request, the first butterfly valve is closed, and the second butterfly valve and the fan are closed after a second preset time period.

[0028] By adopting the above technical solution, when responding to the powder feeding request, the powder remaining amount in the powder storage tank can be determined by acquiring the state of the second material level sensor, and when the powder remaining amount is equal to or lower than the preset minimum material level, the operator is promptly alerted to supplement powder, so as to avoid affecting the normal operation of 3D printing due to insufficient powder. At the same time, by acquiring the current oxygen content data detected by the oxygen content detection sensor, the oxygen content of the powder feeding tank, the powder feeding pipeline and the return air pipeline is determined, and when the oxygen content is higher than or equal to the preset safety threshold, the gas washing operation is promptly performed, so as to ensure that the oxygen content in the system is within a safe range, and reduce the safety risks such as oxidation and explosion of metal powder. When the powder remaining amount in the powder storage tank meets the powder feeding requirement and the oxygen content is lower than the preset safety threshold, the fan and other devices are controlled to feed the powder into the powder feeding tank, so as to realize efficient and safe supply of the powder. When responding to the stop powder feeding request, the corresponding valves and the fan are closed according to the preset time period, so as to ensure the stability and safety of the system when stopping powder feeding, and improve the reliability and efficiency of the metal 3D printing process.

[0029] Optionally, after opening the first butterfly valve after a first preset time period, the process further includes:

[0030] Acquire dynamic level data from the first level sensor;

[0031] When the remaining powder level in the powder storage tank is determined to be lower than or equal to the preset minimum level based on the detection data of the first material level sensor, a stop processing command is generated, the first butterfly valve is controlled to close and the alarm device is controlled to sound an alarm, and after a second preset time, the blower and the second butterfly valve are controlled to close.

[0032] When the amount of powder remaining in the powder storage tank is higher than the preset minimum level based on the dynamic level data of the first level sensor, the powder level data of the second level sensor is obtained.

[0033] When the powder level data from the second level sensor is determined to be at or above the level of the high level sensor, a pause processing command is generated, and the first butterfly valve is closed.

[0034] If, based on the dynamic level data from the second level sensor, it is determined that the powder in the current powder feeding tank remains at or above the position of the high level sensor for a continuous second preset time, a stop processing command is generated, controlling the first butterfly valve to close and the alarm device to sound an alarm. After the second preset time, the blower and the second butterfly valve are controlled to close.

[0035] When the powder level data from the second level sensor is determined to be lower than the position of the high level sensor and / or at or below the position of the low level sensor, a command to continue feeding powder is generated, controlling the first butterfly valve to open and continue feeding powder into the powder tank.

[0036] By adopting the above technical solution, during the powder feeding process, the remaining powder in the powder storage tank can be monitored in real time based on the dynamic level data of the first level sensor. When the remaining powder is lower than or equal to the preset minimum level, a stop processing command can be generated in a timely manner, closing the first butterfly valve and triggering an alarm. Subsequently, the blower and the second butterfly valve are shut down to avoid situations where there is no powder to feed, ensuring the continuity and stability of the powder feeding process. Furthermore, the position of the powder in the feeding tank can be determined based on the powder level data from the second level sensor. When the powder is at or above the position of the high level sensor, powder feeding is paused to prevent powder from being added to the tank. The powder overflow prevention system improves the safety of powder feeding. If, after the second preset time, the powder level in the powder feeding tank is still at or above the position of the high-level sensor, the powder feeding tank may experience a powder feeding failure or the forming chamber may suspend processing. In this case, powder feeding will be stopped to prevent powder overflow from the powder feeding tank. When the powder level is below the position of the high-level sensor and / or at or below the position of the low-level sensor, a powder feeding command will be generated in a timely manner to ensure that the powder feeding tank has a sufficient powder supply. This achieves automatic powder feeding without manual intervention, improves powder feeding efficiency, and reduces labor costs.

[0037] Optionally, the opening of the first butterfly valve after the first preset time period further comprises:

[0038] acquiring a current temperature value detected by the temperature detection sensor, and comparing the current temperature value with a preset safety temperature value;

[0039] if the current temperature value is greater than or equal to the preset safety threshold value, generating a stop processing instruction to control the first butterfly valve, the fan and the second butterfly valve to be closed and control the alarm device to alarm.

[0040] By using the above technical solution, in the powder feeding process, the current temperature value detected by the temperature detection sensor is acquired in real time and compared with the preset safety temperature value, when the current temperature value is greater than or equal to the preset safety threshold value, a stop processing instruction can be generated in time to close the first butterfly valve, the fan and the second butterfly valve and control the alarm device to alarm, realizing temperature loss protection, avoiding damage to the equipment and the powder feeding process caused by abnormal temperature, and protecting the stability and service life of the equipment.

[0041] Optionally, the closing of the second butterfly valve and the fan after the second preset time period further comprises:

[0042] controlling the pinch valve to be opened, and controlling the pinch valve to be closed after a third preset time period.

[0043] By using the above technical solution, after the second butterfly valve and the fan are closed, the pinch valve is opened, so that the pressure of the powder tank, the powder feeding pipeline and the return air pipeline and the external environment is balanced, preventing the powder from being affected by the excessive pressure difference, ensuring the stability of the system pressure, and facilitating the normal operation and maintenance of the system. At the same time, the pinch valve is closed after the third preset time period, which can prevent impurities in the external environment from entering the powder tank, the powder feeding pipeline and the return air pipeline and polluting the powder feeding system.

[0044] In summary, the one or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0045] 1. Automatic powder feeding without manual intervention is realized, the system realizes monitoring of the remaining amount of powder through remote measurement and control devices, controllers, level sensors, etc., and automatically controls the opening and closing of the fan, butterfly valve and other equipment according to preset conditions, so as to realize unattended operation, automatic continuous powder feeding and improve powder feeding efficiency;

[0046] 2. Special anti-blocking structure is provided, the powder outlet pipeline of the powder tank and the powder feeding pipeline are arranged at an inclination at the installation position, and the included angle between the powder outlet direction and the air flow feeding direction in the feeding pipeline is an acute angle, which is beneficial to the smooth entry of the powder into the powder feeding pipeline, and in combination with the circulating system, the probability of powder blocking is reduced, the program-side anti-blocking and powder blocking control design is realized, and the mechanical design cost is reduced;

[0047] 3. The inert atmosphere closed loop powder feeding is realized, the powder feeding and the gas circulation process are in the inert gas atmosphere protection through the inertization control device and the oxygen content detector, the powder oxidation can be effectively prevented, the forming chamber is not disturbed, the safety of the powder feeding process is ensured, the powder pollution is reduced and the loss is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 is a rear side view schematic diagram of a metal 3D printing powder supply system disclosed by the embodiment of the application;

[0049] Figure 2 is a front view structural schematic diagram of a metal 3D printing powder supply system disclosed by the embodiment of the application;

[0050] Figure 3 is a structural schematic diagram of each device in the box of a metal 3D printing powder supply system disclosed by the embodiment of the application;

[0051] Figure 4 is a structural schematic diagram of a circulation system of a metal 3D printing powder supply system disclosed by the embodiment of the application;

[0052] Figure 5 is a structural schematic diagram of an upper powder tank of a metal 3D printing powder supply system disclosed by the embodiment of the application;

[0053] Figure 6 is a sectional view of an upper powder tank of a metal 3D printing powder supply system disclosed by the embodiment of the application;

[0054] Figure 7 is another sectional view of an upper powder tank of a metal 3D printing powder supply system disclosed by the embodiment of the application;

[0055] Figure 8 is a flow schematic diagram of a control method of a metal 3D printing powder supply system disclosed by the embodiment of the application.

[0056] Explanation of reference signs: 1, box body; 11, controller; 121, powder storage tank; 122, second material level sensor; 123, powder outlet pipeline; 124, first butterfly valve; 125, manual butterfly valve; 13, circulating system; 131, fan; 132, powder feeding pipeline; 133, return air pipeline; 14, universal wheel; 15, human-computer interaction device; 16, alarm device; 171, inertization control device; 172, inert gas inlet; 173, gas washing inlet; 174, gas washing outlet; 2, upper powder tank; 21, upper tank powder inlet; 22, powder feeding pipeline; 23, upper tank return air inlet; 24, air outlet pipeline; 25, second butterfly valve; 26, pressure sensor; 27, pressure relief valve; 28, oxygen content detector; 29, backflushing gas pocket; 20, first material level sensor; 201, high material level sensor; 202, low material level sensor; 210, temperature detection sensor; 211, differential pressure detector; 3, connecting pipeline; 4, pressure balance pipeline; 41, pinch valve; 500, electronic device; 501, processor; 502, communication bus; 503, user interface; 504, network interface; 505, memory. DETAILED DESCRIPTION

[0057] In order for those skilled in the art to better understand the technical solutions in the specification, the technical solutions in the specification will be clearly and completely described below in combination with the drawings in the specification. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments.

[0058] In the description of the embodiments of the present application, the words such as "for example" or "for instance" are used to represent an example, illustration or description. Any embodiment or design scheme described as "for example" or "for instance" in the embodiments of the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the words such as "for example" or "for instance" are intended to present the relevant concept in a specific manner.

[0059] In the description of the embodiments of the present application, the term "a plurality of" means two or more. For example, a plurality of systems means two or more systems, and a plurality of screen terminals means two or more screen terminals. In addition, the terms "first" and "second" are used for description purposes only, and should not be interpreted as indicating or implying relative importance or implicitly indicating the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features. The terms "include", "contain", "have" and their variants mean "include but are not limited to", unless otherwise specifically emphasized.

[0060] As Figures 1-7As shown, the system comprises a remote monitoring and control device 5, a powder supply mechanism and at least one powder feeding tank 2 with filter element, wherein the remote monitoring and control device 5 cooperates with the powder supply mechanism and the powder feeding tank 2 to realize accurate monitoring and control of the powder supply process, thereby ensuring stable powder delivery and realizing automatic continuous powder supply.

[0061] Specifically, the remote monitoring and control device 5 functions as a remote IO module in the system and mainly realizes the following functions: data acquisition: electrically connected with the first material level sensor 20, the oxygen content detector 28, the temperature detection sensor 210, the pressure sensor 26, the differential pressure detector 211 and other detection components, and acquires the detection data of each component in real time; signal transmission: establishes a communication connection with the controller 11 through industrial Ethernet, transmits the collected detection data to the controller 11, and receives the control instructions sent by the controller 11; execution control: electrically connected with the second butterfly valve 25 and other execution components, and controls the action of the execution components according to the instructions of the controller 11 or the preset control logic.

[0062] The powder supply mechanism comprises a box body 1, a human-machine interaction device 15, a controller 11, a powder storage tank 121 and a circulation system 13. The box body 1 provides a relatively closed installation space for the entire powder supply mechanism, and the bottom thereof is provided with universal wheels 14 to facilitate the movement and position adjustment of the entire powder supply mechanism. The human-machine interaction device 15 is arranged on the box body 1, and an operator can input instructions, check the system state and the like through the human-machine interaction device 15. The human-machine interaction device 15 can be in the form of a touch screen, a button and the like, for example, a touch screen type human-machine interaction device 15, which is intuitive and convenient to operate and can display various parameters of the system in real time. In the embodiment of the present application, the human-machine interaction device 15 is taken as an example of a hanging HMI touch screen, a hook is fixedly installed on the box body 1, and the hanging HMI touch screen cooperates with the hook to realize its fixation on the box body 1. In addition, a through hole penetrating through the side wall of the box body 1 is formed in the box body 1 to allow the cables for electrically connecting the human-machine interaction device 15 and the alarm device 16 with the controller 11 to pass through.

[0063] It can be understood that the operator can set parameters such as powder feeding amount and safety threshold through the human-machine interaction device 15, and also can check the system running state such as material level information and temperature data.

[0064] The circulating system 13 comprises a fan 131, a powder feeding pipe 132 and a return air pipe 133, forming a powder conveying air flow circulating loop. The fan 131 can be a variable frequency fan 131 installed in the box body 1, the outlet thereof is connected with one end of the powder feeding pipe 132, the return air outlet is connected with one end of the return air pipe 133, the other end of the powder feeding pipe 132 is fixedly connected with the free end of the powder inlet pipe 22 of the powder tank 2 through the connecting pipe 3, the other end of the return air pipe 133 is fixedly connected with the free end of the air outlet pipe 24 of the powder tank 2 through the connecting pipe 3, the connecting pipe 3 is a copper flexible pipe, which has good flexibility and sealing property, can compensate the installation error and absorb the displacement caused by equipment vibration, and can also realize the communication between the circulating system 13 and the powder tank 2 by using different types of connecting pipes 3, so that the same powder feeding mechanism can be used to feed powder to different powder tanks 2.

[0065] The powder storage tank 121 arranged in the box body 1 is used to store the metal powder to be conveyed, and is made of stainless steel, which has good sealing property and corrosion resistance. The second material level sensor 122 is installed in the powder storage tank 121, which can detect the remaining amount of powder in the powder storage tank 121 in real time, and is electrically connected with the controller 11 to transmit the detected material level data to the controller 11 in real time. When the remaining amount of powder in the powder storage tank 121 is lower than the preset minimum material level, the controller 11 will immediately send a powder supplement signal to remind the operator to supplement the metal powder in the powder storage tank 121 in time, so as to effectively ensure that the amount of powder in the powder storage tank 121 is always maintained within a reasonable range, and ensure the stable and continuous operation of the entire powder supply system, avoid the interruption of the 3D printing process caused by insufficient powder, and avoid the safety hazards and resource waste caused by excessive powder.

[0066] The second material level sensor 122 can be a capacitive material level sensor, an ultrasonic material level sensor, etc., which has high sensitivity and is easy to install.

[0067] The powder outlet pipe 123 is installed at the powder outlet of the powder storage tank 121, is communicated with the powder feeding pipe 132 of the circulating system 13, and is inclined at the installation position of the powder feeding pipe 132. The inclination of the powder outlet pipe 123 and the powder feeding pipe 132 makes the included angle between the powder feeding direction and the feeding direction formed by the air flow generated by the fan 131 in the powder feeding pipe 132 be an acute angle, so that the powder can enter the powder feeding pipe 132 more smoothly by using the traction of the air flow and the gravity of the powder itself, and the accumulation and blockage of the powder at the pipe connection position are reduced.

[0068] The first butterfly valve 124 is installed on the powder outlet pipeline 123, is an electric butterfly valve, is electrically connected with the controller 11, and the controller 11 controls the powder supply of the powder storage tank 121 to the powder conveying pipeline 132 by controlling the opening and closing of the first butterfly valve 124; the manual butterfly valve 125 is also installed on the powder outlet pipeline 123, and the manual butterfly valve 125 can be manually operated to control the opening and closing of the powder outlet pipeline 123, thereby improving the reliability of the system.

[0069] The controller 11 is arranged in the box body 1, is the control core of the whole powder supply mechanism, is responsible for receiving and processing data transmitted by various sensors, and controls the operation of various components according to a preset program. In the embodiment of the application, the controller 11 is taken as an example of a PLC controller 11, and other types of controllers 11 capable of realizing the scheme can also be applicable to the scheme, such as a single-chip microcomputer, a microprocessor or other programmable logic control units. These controllers 11 can process sensor signals according to a preset logic program and output corresponding control instructions. In addition, the controller 11 also has an expansion interface for connecting other auxiliary equipment, such as a man-machine interaction device 15 or an alarm device 16, thereby improving the operation convenience and intelligent level of the system.

[0070] The box body 1 is also provided with an alarm device 16 electrically connected with the controller 11, which can include a power-on indicator light, an abnormality alarm light and a buzzer, etc. The power-on indicator light is used to indicate whether the devices in the box body 1 are powered on, the abnormality alarm light is used to prompt the operator whether the powder conveying system is abnormal, and the buzzer is used to emit a high-decibel warning sound when the system has a serious fault or an emergency, so as to attract attention in time in the case of insufficient light or the operator's vision not focusing on the indicator light, to ensure that the operator can quickly detect the abnormality and take corresponding processing measures, to avoid affecting the normal operation of the powder supply system due to failure to handle in time, and even to cause more serious production safety problems.

[0071] The box body 1 is provided with an inertization control device 171 electrically connected with the controller 11, and the box body 1 is provided with an inert gas inlet 172, which is communicated with the inertization control device 171 through a pipeline, for connecting an inert gas (such as argon). The powder conveying pipeline 132 is provided with a gas washing inlet 173, and the air return pipeline 133 is provided with a gas washing outlet 174, which is communicated with an external filtering device, and is discharged into the external environment after filtering by the external filtering device, to avoid pollution to the external environment. The inertization control device 171 is communicated with the gas washing inlet 173 through a pipeline. The powder feeding tank 2 is provided with an oxygen content detector 28 for detecting the oxygen content in the system, which is electrically connected with the remote measurement and control device 5 and transmits the detection data to the remote measurement and control device 5.

[0072] The lower powder outlet of the powder tank 2 is communicated with the forming chamber to provide the powder required for printing. The powder tank 2 is provided with a powder inlet 21 on the sidewall below the filter element, and a powder inlet pipeline 22 is installed at the powder inlet opening. A first material level sensor 20 is installed below the powder inlet 21 to monitor the powder level in the powder tank 2. The first material level sensor 20 includes a high material level sensor 201 and a low material level sensor 202. The low material level sensor 202 is close to the lower powder outlet of the powder tank 2, and the high material level sensor 201 is close to the powder inlet 21. When the powder level is lower than the low material level sensor 202, it indicates that the powder in the powder tank 2 is insufficient and needs to be replenished. When the powder level is higher than the high material level sensor 201, it indicates that the powder in the powder tank 2 is excessive and needs to stop powder supply. The powder tank 2 is provided with an air return opening 23 above the filter element, and an air outlet pipeline 24 is installed at the air return opening 23 to discharge the gas in the circulation process. A second butterfly valve 25 is installed on the air outlet pipeline 24 and the powder inlet pipeline 22, and the second butterfly valve 25 is electrically connected with the remote control device 5. The remote control device 5 can control the opening and closing of the second butterfly valve 25 according to the actual situation to adjust the delivery of the powder and the air return.

[0073] It can be understood that, in order to avoid the powder from the powder inlet pipeline 22 entering the powder tank 2 and colliding with the sidewall of the powder tank 2 and rebounding into the powder inlet pipeline 22, the powder inlet 21 is provided in the shape of a duck egg, which can effectively guide the powder to slide along the arc-shaped inner wall, reduce the direct impact area of the powder with the tank wall, and thus reduce the rebound force. At the same time, the opening structure of the duck egg shape can ensure the powder flow under the premise of ensuring the powder flow, and through the gradual transition of the cross section, the powder entering the powder tank 2 can form a relatively stable flow state, further weaken the rebound phenomenon, ensure that the powder can smoothly enter the tank, and improve the stability and efficiency of the powder replenishment process.

[0074] The filter element of the powder tank 2 plays a filtering role. The powder is filtered through the filter element, and under the action of its own gravity, it falls from the filter element to the lower powder outlet of the powder tank 2, thereby realizing the powder supply to the forming chamber. The filter element can be a paper filter element, a metal filter element, etc. The paper filter element has good filtering effect and low cost, and the metal filter element has high strength and long service life. The filter element of the powder tank 2 is provided with a differential pressure detector 211 for detecting the pressure difference between the two ends of the filter element. When the pressure difference between the two ends of the filter element is too large, it indicates that the filter element may be clogged and needs to be cleaned or replaced. The powder tank 2 is provided with a back-blowing gas bag 29 above the filter element. The back-blowing gas bag 29 is communicated with the inside of the powder tank 2 through a blowing pipeline. The gas outlet end of the blowing pipeline is arranged in the upstream area of the filter element airflow channel in the powder tank 2. A back-blowing pulse valve is arranged on the blowing pipeline and is electrically connected with the controller 11 to control the opening and closing of the back-blowing pulse valve through the controller 11. When the filter element needs to be cleaned, the controller 11 controls the back-blowing pulse valve to open, and the gas in the back-blowing gas bag 29 is quickly blown out to back-blow the filter element and remove the powder attached to the filter element.

[0075] The powder storage tank 121, the powder feeding pipeline 132 and the return air pipeline 133 are each provided with a pressure balance pipeline 4 for communication with the external environment, and the pressure balance pipeline 4 is provided with a pinch valve 41 which is electrically connected to the controller 11. When the powder feeding is completed, the pinch valve 41 is opened to form pressure balance between the powder storage tank 121, the powder feeding pipeline 132 and the return air pipeline 133 and the external environment, so as to avoid damage to the pipelines or poor powder feeding due to excessive pressure.

[0076] The powder storage tank 121, the powder feeding pipeline 132 and the return air pipeline 133 are each provided with a pressure balance pipeline 4 for communication with the external environment, and the pressure balance pipeline 4 is provided with a pinch valve 41 which is electrically connected to the controller 11. When the powder feeding is completed, the pinch valve 41 is opened to form pressure balance between the powder storage tank 121, the powder feeding pipeline 132 and the return air pipeline 133 and the external environment, so as to avoid damage to the pipelines or poor powder feeding due to excessive pressure.

[0077] The inertization control device 171 can inject inert gas into the powder feeding pipeline 132 to reduce the oxygen content in the system and prevent oxidation and other reactions of the metal powder. The oxygen content detector 28 monitors the oxygen content in the powder storage tank 2 in real time. When the oxygen content is higher than the preset safety threshold, the remote control device 5 controls the inertization control device 171 and the second butterfly valve 25 to open for gas washing operation. When the oxygen content is lower than the preset safety threshold, the remote control device 5 controls the inertization control device 171 to close. The temperature detection sensor 210 monitors the temperature in the powder storage tank 2 in real time. When the temperature is too high, the remote control device 5 controls the relevant components to stop working to prevent safety accidents. The pressure sensor 26 monitors the pressure in the powder storage tank 2 in real time. When the pressure is too high, the pressure relief valve 27 is automatically opened to release the pressure and ensure the safety of the system.

[0078] In the embodiment of the present application, the powder supply system realizes precise control of metal 3D printing powder supply through the cooperation of the remote control device 5, the powder supply mechanism and the powder storage tank 2. The circulation system 13 enables the powder to be circulated and delivered in the system, improving the utilization rate and delivery efficiency of the powder. The use of multiple sensors, such as the first level sensor 20, the second level sensor 122, the oxygen content detector 28, the temperature detection sensor 210 and the pressure sensor 26, enables real-time monitoring of various parameters of the system, and the controller 11 controls the system according to these parameters to ensure the stability and precision of the powder supply. At the same time, the inertization control device 171 reduces the oxygen content in the system and improves the safety of the system. Compared with the prior art, the system solves the problems of low efficiency, easy introduction of impurities and lack of monitoring and control mechanism in the traditional powder supply method, and meets the strict requirements of metal 3D printing on powder supply.

[0079] As Figure 8 shown, a control method of a powder supply system for metal 3D printing provided by an embodiment of the application includes the following steps:

[0080] S1, in response to a powder feeding request, open the second butterfly valve.

[0081] S2, based on the powder feeding request, obtain the current state of the second material level sensor, and determine whether the remaining amount of powder in the current powder tank meets the powder feeding requirement based on the current state of the second material level sensor.

[0082] S3, if it is determined based on the current state of the second material level sensor that the remaining amount of powder in the current powder tank is equal to or lower than the preset minimum material level, a powder replenishment signal is generated, and the alarm device is controlled to issue an alarm to prompt the operator to replenish powder.

[0083] S4, and according to the powder feeding request, obtain the current oxygen content data detected by the oxygen content detection sensor, and determine whether the current oxygen content of the current powder tank, the powder feeding pipeline and the return air pipeline is lower than the preset safety threshold based on the current oxygen content data.

[0084] S5, if it is determined based on the current oxygen content data that the current oxygen content of the current powder tank, the powder feeding pipeline and the return air pipeline is higher than or equal to the preset safety threshold, a gas washing instruction is generated, and the gas washing control device is controlled to open.

[0085] S6, when the current oxygen content data detected by the oxygen content detection sensor determines that the current oxygen content of the current powder tank, the powder feeding pipeline and the return air pipeline is lower than the preset safety threshold, a gas washing stop instruction is generated, and the gas washing control device is controlled to close.

[0086] S7, when the remaining amount of powder in the powder tank meets the powder feeding requirement and the current oxygen content is lower than the preset safety threshold, the fan, the first butterfly valve and the second butterfly valve are controlled to open, and the first butterfly valve is opened after a first preset time period, so that the fan feeds the powder into the powder tank.

[0087] S8, in response to a stop powder feeding request, close the first butterfly valve, and close the second butterfly valve and the fan after a second preset time period.

[0088] In the embodiment of the application, when the forming chamber needs powder, the operator issues a powder feeding request on the human-computer interaction device 15, and the controller 11 controls the second butterfly valve 25 to open after receiving the powder feeding request, thereby preparing for air circulation and powder transportation.

[0089] The controller 11 acquires the powder remaining amount data detected by the second material level sensor 122 in the powder storage tank 121, and judges whether the powder remaining amount meets the powder feeding requirement. If the powder remaining amount is equal to or lower than the preset minimum material level, the controller 11 generates an alarm signal to control the alarm device 16 to issue an alarm to prompt the operator to timely supplement the powder in the powder storage tank 121; if the powder remaining amount meets the powder feeding requirement, the next operation is performed.

[0090] The remote measurement and control device 5 acquires the current oxygen content data detected by the oxygen content detector 28, and transmits the acquired data to the controller 11. The controller 11 judges whether the oxygen content in the powder feeding tank 2, the powder feeding pipeline 132 and the return air pipeline 133 is lower than the preset safety threshold according to the current oxygen content data. If the oxygen content is higher than or equal to the preset safety threshold, the controller 11 generates a gas washing instruction to control the inerting control device 171 and the second butterfly valve 25 to open, and inert gas is introduced into the system to displace the air in the system; when the oxygen content detector 28 detects that the oxygen content is lower than the preset safety threshold, the controller 11 generates a gas washing stop instruction to control the inerting control device 171 to close and stop the inert gas from being introduced.

[0091] The preset safety threshold is 100 ppm.

[0092] When the powder remaining amount in the powder storage tank 121 meets the powder feeding requirement and the oxygen content in the system is lower than the preset safety threshold, the controller 11 controls the fan 131 to start and the second butterfly valve 25 to remain open. After a first preset time, the controller 11 controls the first butterfly valve 124 to open, and the powder in the powder storage tank 121 enters the powder feeding tank 2 through the powder outlet pipeline 123, the powder feeding pipeline 132 and the powder inlet pipeline 22 under the action of the airflow generated by the fan 131.

[0093] The first preset time can be 5-20s, such as 5s, 8s, 10s, 15s, etc. The first preset time is set to circulate the gas between the circulating system 13 and the powder feeding tank 2 under the action of the fan 131, which can effectively clean the residual powder in the pipeline.

[0094] In the powder feeding process, by monitoring the state of the powder storage tank 121 and the powder feeding tank 2, the powder remaining amount data in the powder storage tank 121 and the key parameters such as the pressure and temperature of the powder feeding tank 2 are obtained in real time, so as to realize the stability and safety of the powder feeding process. Specifically, the dynamic material level data of the first material level sensor 20 is obtained; when it is determined according to the detection data of the first material level sensor 20 that the powder remaining amount in the powder storage tank 121 is lower than or equal to the preset minimum material level, a stop processing instruction is generated, the first butterfly valve 124 is controlled to be closed, the alarm device 16 is controlled to alarm, and after a second preset time, the fan 131 and the second butterfly valve 25 are controlled to be closed; when it is determined according to the dynamic material level data of the first material level sensor 20 that the powder remaining amount in the powder storage tank 121 is higher than the preset minimum material level, the powder feeding material level data of the second material level sensor 122 is obtained; when it is determined according to the powder feeding material level data of the second material level sensor 122 that the powder in the current powder feeding tank 2 is at or above the position of the high material level sensor 201, a pause processing instruction is generated, and the first butterfly valve 124 is controlled to be closed; if it is determined according to the dynamic material level data of the second material level sensor 122 that the powder in the current powder feeding tank 2 remains at or above the position of the high material level sensor 201 for a second preset time, a stop processing instruction is generated, the first butterfly valve 124 is controlled to be closed, and the alarm device 16 is controlled to alarm, and after a second preset time, the fan 131 and the second butterfly valve 25 are controlled to be closed; when it is determined according to the powder feeding material level data of the second material level sensor 122 that the powder in the current powder feeding tank 2 is lower than the position of the high material level sensor 201 and / or at or lower than the position of the low material level sensor 202, a continue powder feeding instruction is generated, the first butterfly valve 124 is controlled to be opened, and the powder feeding to the powder feeding tank 2 is continued.

[0095] Specifically, by multi-sensor data fusion and hierarchical response mechanism, a multi-level security protection system is constructed. When the powder remaining amount of the powder tank 121 reaches the preset minimum material level threshold, the system immediately triggers the emergency shutdown process, cuts off the powder conveying path by closing the first butterfly valve 124, synchronously starts the alarm device 16 to prompt the operator to intervene, and after the residual powder is cleaned within the second preset time, the fan 131 and the second butterfly valve 25 are closed in turn to avoid the residual powder in the pipeline from being blocked or damp. The high-low double threshold judgment logic is adopted for the material level monitoring of the powder tank 2. When the powder amount reaches or exceeds the position of the high material level sensor 201, the system first generates a pause processing instruction and closes the first butterfly valve 124 to give a buffer time for the natural settlement of the powder. If the high material level state lasts more than the second preset time, it is determined that there is an abnormal accumulation risk, and the processing is stopped immediately and the alarm is started to ensure the safety of the equipment operation. When the powder amount is below the high material level and does not reach the low material level, the system automatically executes the continue powder feeding instruction to maintain stable powder supply by opening the first butterfly valve 124, realizing the continuity of the processing process. This dynamic adjustment mechanism not only avoids the printing interruption caused by insufficient powder, but also prevents the equipment overload caused by excessive powder feeding, effectively improving the stability and safety of powder supply in the metal 3D printing process.

[0096] It is easy to think that the temperature may abnormally rise due to friction, static electricity or other factors during powder feeding. Therefore, a temperature detection sensor 210 is arranged in the powder tank 2 to monitor the temperature in the powder tank 2 in real time to avoid safety accidents such as spontaneous combustion and explosion. Specifically, the current temperature value detected by the temperature detection sensor 210 is obtained, and the current temperature value is compared with the preset safety temperature value. If the current temperature value is greater than or equal to the preset safety temperature value, a stop processing instruction is generated to control the first butterfly valve 124, the fan 131 and the second butterfly valve 25 to be closed and control the alarm device 16 to alarm.

[0097] It can be understood that, in order to further improve the timeliness and reliability of temperature anomaly processing, a three-level temperature early warning mechanism is provided. When it is detected that the current temperature value reaches 80% of the preset safe temperature value, a first early warning is triggered, at this time the system only issues an audible and visual prompt through the alarm device 16, while maintaining the normal operation of the powder feeding process, so that the operator can carry out preliminary troubleshooting before the temperature reaches the dangerous threshold; if the temperature continues to rise to 90% of the preset safe temperature value, a second early warning state is entered, the system automatically reduces the powder feeding rate and starts the cooling fan outside the upper powder tank 2, and the temperature is further inhibited by physical cooling; and when the temperature reaches or exceeds the preset safe temperature value, an emergency shutdown program is immediately executed, in addition to closing the first butterfly valve 124, the fan 131 and the second butterfly valve 25, the inert gas injection device inside the upper powder tank 2 is started synchronously, the oxygen concentration in the tank is quickly reduced, and the risk of spontaneous combustion or explosion is eliminated from the source. In addition, the temperature detection sensor 210 adopts a distributed arrangement scheme, one detection point is arranged at the top, middle and bottom of the tank body, and the average value of the three-point temperature is taken as the current temperature value, so as to avoid misjudgment caused by single sensor failure or local temperature deviation, and ensure the accuracy of temperature monitoring data.

[0098] When receiving the stop powder feeding request, the controller 11 responds to the stop powder feeding request, first controls the first butterfly valve to close, stops the powder tank 121 from supplying powder to the powder feeding pipeline 132, and after a second preset time length, controls the second butterfly valve and the fan 131 to close, stops the air flow circulation. After the second butterfly valve and the fan 131 are closed after the second preset time length, the controller 11 controls the pinch valve 41 to open, balances the pressure inside and outside the system, and controls the pinch valve 41 to close after a third preset time length, completes the entire powder feeding process.

[0099] The second preset time length can be 30-50s, such as 30s, 35s, 40s, 42s, 45s, 50s, etc. The second preset time length is set to clean the powder accumulated in the powder feeding device, make the device safer, prevent blockage, and prolong the service life of the device.

[0100] The third preset time length can be 1-10s, such as 2s, 3s, 5s, etc. The third preset time length is set to ensure that the powder tank 121, the powder feeding pipeline 132 and the return air pipeline 133 form pressure balance with the external environment, and prevent impurities in the external environment from entering the powder tank 121, the powder feeding pipeline 132 and the return air pipeline 133.

[0101] In the embodiment of the present application, the remote measurement and control device 5 is adopted to realize distributed data acquisition and control, thereby improving the response speed and control accuracy of the system; the inclined arrangement of the powder outlet pipeline 123 of the powder storage tank 121 and the powder feeding pipeline 132, in combination with the airflow transportation generated by the fan 131, improves the smoothness of powder transportation and reduces pipeline blockage; multiple monitoring functions such as material level detection, oxygen content detection, temperature detection and pressure detection are integrated, in cooperation with the alarm device 16 and emergency control measures, thereby significantly improving the safety of system operation; the full-process automatic control of powder supply is realized, thereby reducing manual intervention and improving the production efficiency and stability of metal 3D printing; the filter cleaning system and pressure balancing system are arranged, thereby reducing the maintenance cost of the system and prolonging the service life of the equipment.

[0102] The above-described are only exemplary embodiments of the present disclosure, and cannot limit the scope of the present disclosure. That is, any equivalent changes and modifications made in accordance with the teachings of the present disclosure are still within the scope of the present disclosure. Other embodiments of the present disclosure will be readily apparent to those skilled in the art upon considering the disclosure herein.

[0103] The present application is intended to cover any variations, uses, or adaptive changes of the present disclosure that follow the general principles of the present disclosure and include common knowledge or conventional technical means in the technical field not recorded in the present disclosure. The specification and examples are only considered as exemplary, and the scope and spirit of the present disclosure are defined by the claims.

Claims

1. A powder supply system for metal 3D printing, characterized in that, The system includes a remote monitoring and control device (5), a powder supply mechanism, and at least one powder supply tank (2) with a filter element. The powder supply mechanism includes a housing (1), a human-machine interface device (15) installed on the housing (1), a controller (11), a powder storage tank (121), and a circulation system (13) installed inside the housing (1). The powder outlet of the powder supply tank (2) is connected to the forming chamber. The powder supply tank (2) has a powder inlet (21) on its side wall below the filter element. A powder inlet pipe (22) is installed at the powder inlet opening of the powder supply tank. Below the powder inlet (21) of the powder supply tank... A first material level sensor (20) is installed. The powder tank (2) is located above the filter element and has an upper tank return air port (23). An air outlet pipe (24) is installed at the upper tank return air port (23). The circulation system (13) includes a blower (131), a powder feeding pipe (132), and a return air pipe (133). One end of the powder feeding pipe (132) is installed at the air outlet of the blower (131), and the other end of the powder feeding pipe (132) is fixedly connected to the free end of the powder inlet pipe (22). One end of the return air pipe (133) is installed at the blower (131). At the return air inlet, the other end of the return air duct (133) is fixedly connected to the free end of the outlet air duct (24). The return air duct (133) and the outlet air duct (24), as well as the powder feeding duct (132) and the powder inlet duct (22), are all fixedly connected by connecting pipes (3). The powder outlet of the powder storage tank (121) is equipped with a powder outlet duct (123). The powder outlet duct (123) and the powder feeding duct (132) are installed at an angle. The angle of the powder outlet duct (123) makes the powder discharge direction different from that of the powder feeding duct, which is driven by the fan (131) inside the fan (131). The included angle of the feeding direction formed by the airflow is acute. A first butterfly valve (124) is installed on the powder outlet pipe (123). A second material level sensor (122) is installed on the powder storage tank (121). The first material level sensor (20) is electrically connected to the remote monitoring and control device (5). The remote monitoring and control device (5) is communicatively connected to the controller (11). The second material level sensor (122), the first butterfly valve (124), and the blower (131) are all electrically connected to the controller (11). A caster wheel (14) is also installed at the bottom of the box (1).

2. The powder supply system for metal 3D printing according to claim 1, characterized in that, The powder storage tank (121), powder delivery pipe (132) and return air pipe (133) are all equipped with pressure balancing pipes (4) for connecting with the external environment. The pressure balancing pipe (4) is equipped with a pinch valve (41) and the pinch valve (41) is electrically connected to the controller (11). The air outlet pipe (24) and powder inlet pipe (22) are both equipped with second butterfly valves (25) and the second butterfly valves (25) are electrically connected to the remote monitoring and control device (5).

3. The powder supply system for metal 3D printing according to claim 2, characterized in that, The housing (1) is also equipped with an inerting control device (171) electrically connected to the controller (11). An inerting gas inlet (172) is provided on the housing (1). The inerting gas inlet (172) is connected to the inerting control device (171). A washing gas inlet (173) is provided on the powder delivery pipe (132). A washing gas outlet (174) connected to an external filtration device is provided on the return air pipe (133). The inerting control device (171) is connected to the washing gas inlet (173). An oxygen content detector (28) and a temperature detection sensor (210) are installed in the powder loading tank (2). A pressure sensor (26) and a pressure relief valve (27) are installed on the powder loading tank (2). The oxygen content detector (28), temperature detection sensor (210), pressure sensor (26), and pressure relief valve (27) are all electrically connected to the remote monitoring and control device (5).

4. The powder supply system for metal 3D printing according to claim 3, characterized in that, The first material level sensor (20) includes a high material level sensor (201) and a low material level sensor (202). The low material level sensor (202) is close to the powder outlet of the upper powder tank (2), and the high material level sensor (201) is close to the powder inlet (21) of the upper tank. An alarm device (16) is also installed on the housing (1). The alarm device (16) is electrically connected to the controller (11).

5. The powder supply system for metal 3D printing according to claim 4, characterized in that, The filter element of the powder tank (2) is equipped with a differential pressure detector (211) for detecting the pressure difference between the two ends of the filter element. The differential pressure detector (211) is electrically connected to the remote monitoring and control device (5). The powder tank (2) is equipped with a backflush air manifold (29) above the filter element. The backflush air manifold (29) is connected to the inside of the powder tank (2) through a blowing pipe. The outlet of the blowing pipe is located in the upstream area of ​​the airflow channel of the filter element inside the powder tank (2). A backflush pulse valve is provided on the blowing pipe. The backflush pulse valve is electrically connected to the controller (11) to control the opening and closing of the backflush pulse valve through the controller (11).

6. The powder supply system for metal 3D printing according to claim 4, characterized in that, A manual butterfly valve (125) is also installed on the powder outlet pipe (123).

7. A control method for a powder supply system for metal 3D printing, characterized in that, The powder supply system for metal 3D printing according to any one of claims 4-6, the method comprising: In response to the powder delivery request, open the second butterfly valve; Based on the powder delivery request, the current state of the second level sensor (122) is obtained, and based on the current state of the second level sensor (122), it is determined whether the remaining amount of powder in the current powder storage tank (121) meets the powder delivery requirements. If the current state of the second level sensor (122) determines that the remaining amount of powder in the current powder storage tank (121) is equal to or lower than the preset minimum level, a powder replenishment signal is generated, and the alarm device (16) is controlled to issue an alarm to prompt the operator to replenish the powder. And according to the powder delivery request, the current oxygen content data detected by the oxygen content detection sensor is obtained, and based on the current oxygen content data, it is determined whether the current oxygen content of the current powder loading tank (2), powder delivery pipeline (132) and return air pipeline (133) is lower than the preset safety threshold. If, based on the current oxygen content data, it is determined that the current oxygen content of the powder feeding tank (2), powder delivery pipe (132), and return air pipe (133) is higher than or equal to the preset safety threshold, a gas scrubbing command is generated to control the gas scrubbing control device to open. When the current oxygen content data detected by the oxygen content detection sensor determines that the current oxygen content of the current powder tank (2), powder delivery pipeline (132) and return air pipeline (133) is lower than the preset safety threshold, a gas washing stop command is generated to control the gas washing control device to shut down. When the remaining amount of powder in the powder storage tank (121) meets the powder delivery requirements and the current oxygen content is lower than the preset safety threshold, the control fan (131), the first butterfly valve (124) and the second butterfly valve (25) are opened. After a first preset time, the first butterfly valve (124) is opened so that the fan (131) delivers the powder to the powder loading tank (2). In response to the request to stop powder feeding, the first butterfly valve (124) is closed, and the second butterfly valve (25) and the fan (131) are closed after a second preset time.

8. The control method for a powder supply system for metal 3D printing according to claim 7, characterized in that, After opening the first butterfly valve (124) after the first preset time period, the following is also included: Acquire dynamic level data from the first level sensor (20); When the amount of powder remaining in the powder storage tank (121) is lower than or equal to the preset minimum level, the processing stop command is generated based on the detection data of the first material level sensor (20). The first butterfly valve (124) is closed and the alarm device (16) is activated. After a second preset time, the blower (131) and the second butterfly valve (25) are closed. When the amount of powder remaining in the powder storage tank (121) is higher than the preset minimum level, based on the dynamic level data of the first level sensor (20), the powder level data of the second level sensor (122) is obtained. When the powder level data of the second material level sensor (122) is determined to be at or above the position of the high material level sensor (201), a pause processing command is generated and the first butterfly valve (124) is controlled to close. If, based on the dynamic level data of the second level sensor (122), it is determined that the powder in the current powder tank (2) remains at or above the position of the high level sensor (201) for a continuous second preset time, a stop processing command is generated, controlling the first butterfly valve (124) to close and controlling the alarm device (16) to sound an alarm, and after the second preset time, controlling the blower (131) and the second butterfly valve (25) to close; Based on the powder level data from the second level sensor (122), when the powder in the current powder tank (2) is lower than the position of the high level sensor (201) and / or at or below the position of the low level sensor (202), a powder feeding command is generated, and the first butterfly valve (124) is opened to continue feeding powder into the powder tank (2).

9. The control method for a powder supply system for metal 3D printing according to claim 7, characterized in that, After opening the first butterfly valve (124) after the first preset time period, the following is also included: The current temperature value detected by the temperature detection sensor (210) is obtained, and the current temperature value is compared with a preset safe temperature value. If the current temperature value is greater than or equal to the preset safe temperature value, a stop processing command is generated, controlling the first butterfly valve (124), the fan (131), and the second butterfly valve (25) to close and controlling the alarm device (16) to sound an alarm.

10. The control method for a powder supply system for metal 3D printing according to claim 7, characterized in that, After the second butterfly valve (25) and the blower (131) are closed after the second preset time, the following is also included: The clamp valve (41) is opened and then closed after a third preset time period.

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