A 3D printer powder turnover auxiliary device

Abstract

The present application relates to the technical field of 3D printing, and more particularly to a 3D printer powder turnover auxiliary device, comprising: a powder overflow collecting mechanism for collecting the overflow powder of a 3D printer, a fan unit for outputting high-pressure air to convey powder and adjusting the air volume; a powder overflow screening mechanism for screening powder; a screening control module for determining the screening of powder based on the volume of powder in the powder tank; an oxygen replacement mechanism for introducing and discharging inert gas to control the oxygen content; a gas replacement control module for starting the gas replacement process and adjusting the pressure of the powder conveying pipeline; and a cyclone separation assembly for separating the powder in conveying from the air. The present application solves the problem of unstable powder screening efficiency of the 3D printer which easily leads to pipeline blockage.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and more particularly to a powder turnover auxiliary device for 3D printers. Background Technology

[0002] In recent years, the application of SLM 3D printing has developed rapidly, with printing equipment quickly evolving towards larger format, higher stroke, and multiple lasers. This has led to a significant increase in powder demand during operation. Furthermore, the conventional powder circulation process for existing equipment is a single-machine, independent cycle, requiring one or two operators to coordinate powder transport and sieving for each cycle, resulting in high physical labor intensity. Leakage of metal powder during circulation can pollute the environment and even pose occupational health risks to operators. Constant monitoring of equipment operation and remaining powder levels is necessary, and powder buffered in the overflow bin cannot be promptly incorporated into the powder circulation process, leading to low powder utilization and increased powder demand.

[0003] Chinese Invention Patent Publication No. CN118306008A discloses a powder suction, sieving, and conveying integrated system for 3D printing equipment and the 3D printing equipment itself. The system, through a control device, automatically cycles through a powder suction device, a sieving transfer station, a suction sieve device, and a powder conveying transfer station after triggering an automatic operation signal. This cycle involves the powder suction device collecting powder, the sieving transfer station processing powder, the suction sieve device suctioning powder, and the powder conveying transfer station conveying powder. However, this system suffers from problems such as unstable sieving efficiency and easy pipe blockage. Summary of the Invention

[0004] To address this issue, the present invention provides a 3D printer powder turnover auxiliary device to overcome the problem of unstable powder sieving efficiency in existing 3D printers, which easily leads to pipe blockage.

[0005] To achieve the above objectives, the present invention provides a 3D printer powder turnover auxiliary device, comprising:

[0006] The overflow powder collection mechanism includes two overflow powder cans for collecting printer powder, a first pneumatic butterfly valve and a third pneumatic butterfly valve for controlling the printer powder to enter the overflow powder cans, a second pneumatic butterfly valve and a fourth pneumatic butterfly valve for controlling the powder in the overflow powder cans to fall into the fan circulation pipe, and a first level sensor and a second level sensor for detecting the amount of overflow powder in the overflow powder cans.

[0007] The overflow powder screening mechanism includes a screening storage tank for storing powder to be screened, a linear screen for screening powder by an ultrasonic generator, a new powder cart for storing the screened powder, a large particle tank for storing large-diameter screened powder, and a third level sensor and a fourth level sensor for monitoring the material level of the screening storage tank and the new powder cart, respectively.

[0008] An oxygen replacement mechanism includes a first to a fifth filling control valve for introducing inert gas, a first to a fifth exhaust control valve for discharging inert gas, and an oxygen detection device for detecting the oxygen content in the overflow tank, the filter, and the linear sieve, respectively.

[0009] The screening control module includes a first control unit for determining whether to open or close the second pneumatic butterfly valve and the fourth pneumatic butterfly valve based on the powder volume in the overflow tank, and a second control unit for determining the wind speed or ultrasonic frequency in the screening pipeline based on the material level in the new powder cart and the screening storage tank.

[0010] The gas replacement control module includes a third control unit for determining gas replacement based on the result that the oxygen detection device detects data that is greater than or equal to a preset oxygen content safety threshold, and a fourth control unit for adjusting the pressure of the powder delivery pipeline.

[0011] The fan unit is used to output high-pressure air to circulate and transport powder in a closed-loop pipeline, and to adjust the air volume according to the powder volume.

[0012] A cyclone separation assembly, comprising a first cyclone separator and a second cyclone separator for separating powder from air.

[0013] Furthermore, it also includes:

[0014] The fan duct filtration module includes a filter chamber located above the fan duct. The filter chamber contains a filter used to filter out small amounts of powder that are not completely separated in the cyclone separator, providing a clean environment for the fan inlet. Differential pressure detectors are installed on the inner and outer sides of the filter to detect filter blockage in real time and perform backflushing based on the result that the detected differential pressure is greater than a preset differential pressure threshold. A recovery tank is installed at the bottom of the filter chamber to collect the filtered powder.

[0015] The residual material calculation unit is used to calculate whether there is enough powder in the first cyclone separator after each powder feeding process. In response to the powder in the first cyclone separator being lower than the preset lower limit value, the tenth pneumatic butterfly valve is opened to send the powder into the first cyclone separator.

[0016] Furthermore, the overflow powder collection mechanism determines to close the first pneumatic butterfly valve and open the second pneumatic butterfly valve based on the result that the powder volume in the first overflow powder tank is greater than or equal to 60% of the capacity of the first overflow powder tank, and determines to close the second pneumatic butterfly valve and open the first pneumatic butterfly valve based on the result that the powder volume in the first overflow powder tank is less than 60% of the capacity of the first overflow powder tank.

[0017] Furthermore, the overflow powder collection mechanism determines to close the third pneumatic butterfly valve and open the fourth pneumatic butterfly valve based on the result that the powder volume in the second overflow powder tank is greater than or equal to 60% of the capacity of the second overflow powder tank, and determines to close the fourth pneumatic butterfly valve and open the third pneumatic butterfly valve based on the result that the powder volume in the second overflow powder tank is less than 60% of the capacity of the second overflow powder tank.

[0018] Furthermore, the overflow powder collection mechanism determines the powder delivery volume based on the difference between the detection data of the first level sensor and the second level sensor at the start and end of the powder delivery operation; the gas replacement control module determines the total amount of gas in the powder delivery pipeline based on the powder delivery volume and a preset solid-gas ratio, and inputs and discharges inert gas into the powder delivery pipeline to maintain the internal pressure of the pipeline within a preset range.

[0019] Furthermore, the screening control module determines to open the eighth pneumatic butterfly valve and start the screening operation based on the material level sensor inside the screening storage tank detecting that the material level has reached 60% of the total capacity.

[0020] Furthermore, the screening control module determines the real-time screening speed based on the difference between the material level decrease detected by the third material level sensor and the material level increase detected by the fourth material level sensor during the screening operation, and the gas displacement control module adjusts the internal pressure of the screening pipeline or the ultrasonic frequency based on the real-time screening speed.

[0021] Furthermore, the screening control module determines to reduce the ultrasonic frequency based on the result that the real-time screening speed is greater than the preset screening speed upper limit; the gas replacement control module determines to increase the air velocity inside the screening pipeline based on the result that the real-time screening speed is less than the preset screening speed lower limit.

[0022] The decrease in ultrasonic frequency is positively correlated with the product of the ratio of the real-time screening speed to the preset screening speed upper limit and the first adjustment coefficient, and the increase in wind speed inside the screening pipeline is positively correlated with the product of the ratio of the real-time screening speed to the preset screening speed upper limit and the second adjustment coefficient.

[0023] Furthermore, when the first cyclone separator receives the 3D printer's operating command, it opens the sixteenth pneumatic butterfly valve to supply powder to the 3D printer.

[0024] Furthermore, the filter differential pressure detector detects the pressure difference between the outside and inside of the filter when the fan unit is running. Based on the result that the pressure difference detection data is greater than or equal to a preset pressure difference threshold, it determines to suspend the current operation and open the backflush canister. The powder is blown into the inside of the filter by the compressed inert gas in the backflush canister, and the powder layer attached to the outside of the filter is blown off.

[0025] Compared with the prior art, the beneficial effect of the present invention is that the oxygen replacement mechanism in the present invention is not simply filled with inert gas, but dynamically adjusted based on real-time oxygen content detection to ensure that the key chamber is always in an ultra-low oxygen environment, fundamentally preventing the oxidation of active metal powders such as titanium alloy and aluminum alloy, and ensuring operational safety.

[0026] Furthermore, the present invention promptly draws the large-particle oxide powder mixed in the overflow powder tank to the screening and storage tank for buffering, and uses an ultrasonic vibrating screen device to promptly screen the buffered powder and let it fall into the new powder tank device for the next cycle of powder feeding to the 3D printing equipment.

[0027] Furthermore, the equipment automatically detects oxygen content and replaces oxygen during operation, which not only protects the powder from oxidation but also ensures safety and explosion-proof operation during powder conveying.

[0028] Furthermore, the blower pipeline filtration module and backflushing design in this invention solve the common problem of filter clogging in powder conveying. By monitoring the degree of clogging through a differential pressure sensor and initiating pulse backflushing when necessary, the filter can be automatically cleaned, avoiding the reduction of system airflow or even shutdown due to clogging, thus ensuring the stability of long-term continuous production.

[0029] Furthermore, the screening control module in this invention can calculate and adjust the screening speed in real time according to changes in material level. By adjusting the ultrasonic frequency or pipeline wind speed, it can avoid material blockage or empty running. Compared with traditional timed or fixed-frequency screening, this adaptive control strategy can maximize screening efficiency and reduce wear on the screen. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the 3D printer powder turnover auxiliary equipment according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the gas replacement logic of the 3D printer powder turnover auxiliary equipment according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the powder suction logic of the 3D printer powder turnover auxiliary equipment according to an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the powder screening logic of the 3D printer powder turnover auxiliary equipment according to an embodiment of the present invention;

[0034] Among them, 100 is the 3D printer main unit; 101 is the first overflow toner tank; 102 is the second overflow toner tank; 201 is the first pneumatic butterfly valve; 202 is the second pneumatic butterfly valve; 203 is the third pneumatic butterfly valve; 204 is the fourth pneumatic butterfly valve; 205 is the fifth pneumatic butterfly valve; 206 is the sixth pneumatic butterfly valve; 207 is the seventh pneumatic butterfly valve; 208 is the eighth pneumatic butterfly valve; 209 is the ninth pneumatic butterfly valve; 210 is the tenth pneumatic butterfly valve; 211 is the tenth pneumatic butterfly valve. 1. Pneumatic butterfly valve; 212. Twelfth pneumatic butterfly valve; 213. Thirteenth pneumatic butterfly valve; 214. Fourteenth pneumatic butterfly valve; 215. Fifteenth pneumatic butterfly valve; 216. Sixteenth pneumatic butterfly valve; 217. Seventeenth pneumatic butterfly valve; 218. Eighteenth pneumatic butterfly valve; 301. First inflation control valve; 302. First exhaust control valve; 303. Second inflation control valve; 304. Second exhaust control valve; 305. Third inflation control valve; 30 6-Third exhaust control valve; 307-Fourth inflation control valve; 308-Fifth inflation control valve; 309-Fourth exhaust control valve; 310-Fifth exhaust control valve; 401-First level sensor; 402-Second level sensor; 403-Third level sensor; 404-Fourth level sensor; 405-Fifth level sensor; 501-First cyclone separator; 502-Second cyclone separator; 601-Screening storage tank; 701-Linear screen; 702-Ultrasonic generator; 703-Linear screen oxygen detection device; 801-New powder cart; 802-Large particle tank; 901-Filter chamber; 902-Filter; 903-Filter differential pressure detector; 904-Pulse valve; 905-Backflush tank; 906-Filter oxygen detection device; 907-Filter pressure detector; 908-Recovery tank; 909-Blower unit; 910-Blower unit differential pressure detector. Detailed Implementation

[0035] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0036] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0037] Please see Figure 1 As shown, it is a structural schematic diagram of a 3D printer powder turnover auxiliary device according to an embodiment of the present invention, including:

[0038] The overflow powder collection mechanism includes two overflow powder cans for collecting printer powder, a first pneumatic butterfly valve 201 and a third pneumatic butterfly valve 203 for controlling the printer powder to enter the overflow powder cans, a second pneumatic butterfly valve 202 and a fourth pneumatic butterfly valve 204 for controlling the powder in the overflow powder cans to fall into the fan circulation pipe, and a first level sensor 401 and a second level sensor 402 for detecting the amount of overflow powder in the overflow powder cans.

[0039] The overflow powder screening mechanism includes a screening storage tank 601 for storing powder to be screened, a linear screen 701 for screening powder by an ultrasonic generator 702, a new powder cart 801 for storing screened powder, a large particle tank 802 for storing large-diameter screened powder, and a third level sensor 403 and a fourth level sensor 404 for monitoring the material levels of the screening storage tank 601 and the new powder cart 801, respectively.

[0040] An oxygen replacement mechanism includes a first filling control valve 301, a second filling control valve 303, a third filling control valve 305, a fourth filling control valve 307, and a fifth filling control valve 308 for introducing inert gas; a first exhaust control valve 302, a second exhaust control valve 304, a third exhaust control valve 306, a fourth exhaust control valve 309, and a fifth exhaust control valve 310 for discharging inert gas; and oxygen detection devices for oxygen content respectively installed in the first overflow tank 101, the second overflow tank 102, the filter 902, and the linear sieve 701.

[0041] The screening control module includes a first control unit for determining whether to open or close the second pneumatic butterfly valve 202 and the fourth pneumatic butterfly valve 204 based on the powder volume in the overflow tank, and a second control unit for determining the real-time screening speed based on the material level in the new powder cart 801 and the screening storage tank 601, and determining the wind speed or ultrasonic frequency in the screening pipeline based on the real-time screening speed.

[0042] The gas replacement control module includes a third control unit for determining gas replacement based on the result that the oxygen detection device detects data that is greater than or equal to a preset oxygen content safety threshold, and a fourth control unit for adjusting the pressure of the powder delivery pipeline.

[0043] The preset safe threshold for oxygen content is 1000 ppm, which is based on the safety standards of the metal powder industry. An oxygen content exceeding 1000 ppm will significantly increase the risk of oxidation and explosion.

[0044] The fan unit 909 is used to output high-pressure air to circulate and transport powder in a closed-loop pipeline, and to adjust the air volume according to the powder volume.

[0045] A cyclone separator assembly includes a first cyclone separator 501 and a second cyclone separator 502 for separating powder in transit from air.

[0046] Specifically, it also includes:

[0047] The fan duct filtration module includes a filter chamber 901 located above the fan duct, which contains a filter 902 for filtering out small amounts of powder that are not completely separated in the cyclone separator, thus providing a clean environment for the fan inlet. Differential pressure detectors 903 are installed on the inner and outer sides of the filter 902 to detect filter blockage in real time and perform backflushing based on the detected differential pressure exceeding a preset threshold. A recovery tank 908 is installed at the bottom of the filter chamber to collect the filtered powder.

[0048] The residual material calculation unit is used to calculate whether there is enough powder in the first cyclone separator 501 after each powder feeding process. In response to the powder level in the first cyclone separator 501 being lower than the preset lower limit, the bottom butterfly valve of the new powder cart is opened to send powder into the first cyclone separator.

[0049] The preset material level lower limit is 30% of the volume of the first cyclone separator. If the level is below 30%, there is a risk of powder supply interruption.

[0050] Specifically, the overflow powder collection mechanism determines to close the first pneumatic butterfly valve 201 and open the second pneumatic butterfly valve 202 based on the result that the volume of powder in the first overflow powder tank 101 is greater than or equal to 60% of the capacity of the first overflow powder tank 101, and determines to close the second pneumatic butterfly valve 202 and open the first pneumatic butterfly valve 201 based on the result that the volume of powder in the first overflow powder tank 101 is less than 60% of the capacity of the first overflow powder tank 101.

[0051] Furthermore, the overflow powder collection mechanism determines to close the third pneumatic butterfly valve 203 and open the fourth pneumatic butterfly valve 204 based on the result that the powder volume in the second overflow powder tank 102 is greater than or equal to 60% of the capacity of the second overflow powder tank 102, and determines to close the fourth pneumatic butterfly valve 204 and open the third pneumatic butterfly valve 203 based on the result that the powder volume in the second overflow powder tank 102 is less than 60% of the capacity of the second overflow powder tank 102.

[0052] Specifically, the overflow powder collection mechanism determines the powder delivery volume based on the difference between the detection data of the first level sensor and the second level sensor at the start and end of the powder delivery operation; the gas replacement control module determines the total amount of gas in the powder delivery pipeline based on the powder delivery volume and a preset solid-gas ratio, and inputs and discharges inert gas into the powder delivery pipeline to maintain the internal pressure of the pipeline within a preset range.

[0053] The preset solid-to-gas ratio is 1:5, indicating that the volume ratio of powder to inert gas is 1:5. This value is an empirical value in pneumatic conveying engineering. Under a pressure of 0.01MPa to 0.03MPa, this solid-to-gas ratio can balance conveying efficiency and pipeline blockage risk. In this embodiment, the preset pressure value is preferably 0.02MPa. This value is the typical working pressure of a closed-loop pneumatic conveying system. Below 0.01MPa, powder deposition is likely to occur, and above 0.03MPa, powder breakage is likely to occur. The value of 0.02MPa is suitable for most metal powder particle sizes.

[0054] Specifically, the screening control module determines to open the eighth pneumatic butterfly valve and start the screening operation based on the material level sensor inside the screening storage tank detecting that the material level has reached 60% of the total capacity.

[0055] Specifically, the screening control module determines the real-time screening speed based on the difference between the decrease in material level detected by the third material level sensor and the increase in material level detected by the fourth material level sensor during the screening operation, and the gas replacement control module adjusts the internal pressure of the screening pipeline or the ultrasonic frequency based on the real-time screening speed.

[0056] The specific calculation method for real-time screening speed is as follows:

[0057] V = (H2 - H1) / t

[0058] Where V is the real-time screening speed, H2 is the increase in material level inside the new powder car, H1 is the decrease in material level inside the screening storage tank, and t is the screening time.

[0059] Specifically, the screening control module determines to reduce the ultrasonic frequency based on the result that the real-time screening speed is greater than the preset screening speed upper limit; the gas replacement control module determines to increase the air velocity inside the screening pipeline based on the result that the real-time screening speed is less than the preset screening speed lower limit.

[0060] The decrease in ultrasonic frequency is positively correlated with the product of the ratio of the real-time screening speed to the preset upper limit of screening speed and the first adjustment coefficient, and the increase in wind speed inside the screening pipeline is positively correlated with the product of the ratio of the real-time screening speed to the preset lower limit of screening speed and the second adjustment coefficient.

[0061] In this embodiment, the actual screening efficiency of the combination of linear screen and ultrasonic wave is 0 kg / min to 2 kg / min. The upper limit of the preset screening speed is preferably 2 kg / min, and the lower limit of the preset screening speed is preferably 0 kg / min. If the screening speed exceeds the upper limit, the screening will be incomplete. If it is lower than the lower limit, it means that the screen has been blocked and the ultrasonic vibration effect has been weakened.

[0062] The preferred value for the first adjustment coefficient is 0.75. This value controls the amplitude of the ultrasonic frequency reduction. A value less than 1 avoids a sudden drop in frequency that could cause the screening to stop. Simulation verification shows that 0.75 can achieve smooth adjustment.

[0063] The second adjustment coefficient is preferably set at 1.3. This value controls the increase in wind speed. A value greater than 1 ensures effective compensation at low speeds. 1.3 is the experimentally optimized value to avoid dust flying caused by sudden increases in wind speed.

[0064] The method for calculating the reduction value of ultrasonic frequency is as follows:

[0065] F = k1 × (V / V1) × F0

[0066] Where F is the ultrasonic frequency reduction value, k1 is the first adjustment coefficient, preferably 0.75, V is the real-time screening speed, V1 is the preset screening speed upper limit, and F0 is the frequency adjustment reference value, preferably 20kHz.

[0067] The calculation method for the increase in internal air velocity in the screening pipeline is as follows:

[0068] W = k2 × (V / V2) × W0

[0069] Where W is the wind speed increase, k2 is the second adjustment coefficient, preferably 1.3, V is the real-time screening speed, V2 is the preset screening speed lower limit, and W0 is the wind speed adjustment benchmark value, preferably 15m / s.

[0070] Specifically, when the first cyclone separator 501 receives the 3D printer's operating command, it opens the sixteenth pneumatic butterfly valve 216 to supply powder to the 3D printer.

[0071] Specifically, the filter differential pressure detector detects the pressure difference between the outside and inside of the filter when the fan unit is running. Based on the result that the differential pressure detection data is greater than or equal to a preset differential pressure threshold, it determines to suspend the current operation and open the backflush canister. The powder is blown into the inside of the filter by the compressed inert gas in the backflush canister, and the powder layer attached to the outside of the filter is blown off.

[0072] The preset differential pressure threshold is 25000Pa, which is a common clogging warning threshold for industrial filtration systems; exceeding this value will cause a surge in fan load and unstable powder delivery.

[0073] Please see Figure 2 As shown, it is a schematic diagram of the gas replacement logic of the 3D printer powder turnover auxiliary equipment in an embodiment of the present invention. When the gas replacement control module detects that the oxygen content is greater than or equal to 1000ppm, the gas replacement process is started.

[0074] In this embodiment, the gas replacement process in the first region is as follows:

[0075] Close the first pneumatic butterfly valve 201, the second pneumatic butterfly valve 202, the third pneumatic butterfly valve 203, and the fourth pneumatic butterfly valve 204, and simultaneously open the first inflation control valve 301 and the second inflation control valve 303. After the inert gas enters the first overflow tank 101 and the second overflow tank 102, open the first exhaust control valve 302 and the second exhaust control valve 304 to discharge the inert gas.

[0076] In this embodiment, the gas replacement process in the second region is as follows:

[0077] Open the fifth inflation control valve 308 to fill in inert gas, and open the twelfth pneumatic butterfly valve 212, the fourteenth pneumatic butterfly valve 214, the fifteenth pneumatic butterfly valve 215 and the eighteenth pneumatic butterfly valve 218. The inert gas enters the first cyclone separator 501 through the fifteenth pneumatic butterfly valve 215, and is discharged through the fourteenth pneumatic butterfly valve 214, the twelfth pneumatic butterfly valve 212 and the blower unit 909 to the fourth exhaust control valve 309.

[0078] In this embodiment, the gas replacement process in the third region is as follows:

[0079] Open the third inflation control valve 305 to inflate inert gas, and open the fifth pneumatic butterfly valve 205, the seventh pneumatic butterfly valve 207 and the fifth exhaust control valve 310. The inert gas is discharged through the fifth pneumatic butterfly valve 205 and the seventh pneumatic butterfly valve 207 to the fifth exhaust control valve 310.

[0080] Please see Figure 3 As shown, this is a schematic diagram of the powder suction logic of the 3D printer powder turnover auxiliary equipment according to an embodiment of the present invention. In this embodiment, the powder suction process of the equipment is as follows:

[0081] During the printing process, the scraper of the 3D printer main unit sweeps excess powder from the powder-spreading surface into the first overflow powder tank 101 and the second overflow powder tank 102 on both sides of the main unit. When the first material level sensor 401 or the second material level sensor 402 detects that the material level has reached 60% of the corresponding overflow powder tank capacity, the bottom butterfly valve of the overflow powder tank is opened and the fan unit 909 is started at the same time. The fifth pneumatic butterfly valve 205 is opened to transport the powder to the second cyclone separator 502 for separation. The seventh pneumatic butterfly valve 207, the sixth pneumatic butterfly valve 206 and the seventeenth pneumatic butterfly valve 217 are opened, and the powder falls into the screening storage tank 601 under the action of gravity.

[0082] The third level sensor 403 detects that the material level is greater than or equal to 60% of the total volume and stops the powder suction process.

[0083] In this embodiment, the powder feeding process of the equipment includes:

[0084] After receiving the powder feeding instruction from the host, the equipment starts the gas replacement control module to replace the oxygen content to below 1000ppm. If the level of the fourth material level sensor 404 is greater than or equal to 50% of the capacity, it means that there is enough powder in the new powder car for adding powder. Otherwise, it means that the powder needs to be screened to provide powder for the new powder car.

[0085] If the level detected by the fifth level sensor 405 is greater than or equal to 50% of the capacity, it indicates that there is enough buffer powder in the cyclone separator. Then, the sixteenth pneumatic butterfly valve 216 is opened, and the fourteenth pneumatic butterfly valve 214 and the fifteenth pneumatic butterfly valve 215 are closed. The powder in the first cyclone separator 501 slides into the powder storage bin of the equipment.

[0086] If the material level detected by the fifth level sensor 405 is less than 50% of the capacity, the blower unit 909 needs to transport the powder to the first cyclone separator 501. At this time, the fourteenth pneumatic butterfly valve 214 and the fifteenth pneumatic butterfly valve 215 are opened, and the sixteenth pneumatic butterfly valve 216 is closed.

[0087] Open the twelfth pneumatic butterfly valve 212 and the seventeenth pneumatic butterfly valve 217, start the fan unit 909. If the differential pressure detector 910 of the fan unit detects a value greater than or equal to 25000Pa, the fan will continue to run until the differential pressure is less than 25000Pa.

[0088] Open the tenth pneumatic butterfly valve 210; close the ninth pneumatic butterfly valve 209; the powder in the new powder car falls into the powder delivery pipeline and is sent to the first cyclone separator 501 for storage under the action of the blower until the main equipment issues the powder addition end command;

[0089] After the equipment issues the powder feeding end command, the powder feeding process continues to run until the fifth material level sensor 405 shows a material level greater than or equal to 50% of the capacity, at which point the equipment powder feeding process ends.

[0090] Please see Figure 4 As shown, this is a schematic diagram of the powder screening logic of the 3D printer powder turnover auxiliary equipment according to an embodiment of the present invention. In this embodiment, the powder screening process of the equipment includes:

[0091] Start the gas replacement control module to replace the oxygen content to below 1000ppm. If the fourth material level sensor 404 detects that the material level is less than 30% of the volume, it means that there is enough volume in the new powder car for the powder screening process. Otherwise, it means that the equipment powder feeding process must be started before the powder screening can be carried out.

[0092] If the third level sensor 403 detects 30% of the material level volume, it means that there is enough buffered powder in the screening storage tank for the screening process; otherwise, it means that the screening process can only be carried out after the equipment's powder suction process is started.

[0093] After starting the powder screening process, close the seventh pneumatic butterfly valve 207 and the tenth pneumatic butterfly valve 210, and open the eighth pneumatic butterfly valve 208; start the ultrasonic generator 702 and open the ninth pneumatic butterfly valve 209; until the third level sensor 403 or the fourth level sensor 404 reaches 60% of the total volume, the powder screening process ends.

[0094] In this embodiment, the equipment backflushing process includes:

[0095] When the filter differential pressure detector 903 detects a value greater than or equal to 25000Pa, the equipment powder feeding process or the equipment powder suction process is suspended, and the equipment backflushing process is started.

[0096] Open the pulse valve 904 to allow the high-pressure inert gas stored in the backflush tank 905 to blow away the outer layer of the filter. Open the eighteenth pneumatic butterfly valve 218 to allow the blown-off powder to fall into the recovery tank 908. The backflush gas is discharged through the fourth exhaust control valve 309.

[0097] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A 3D printer powder turnover auxiliary device, characterized in that, include: The overflow powder collection mechanism includes two overflow powder cans for collecting printer powder, a first pneumatic butterfly valve and a third pneumatic butterfly valve for controlling the powder to enter the overflow powder cans, a second pneumatic butterfly valve and a fourth pneumatic butterfly valve for controlling the powder in the overflow powder cans to fall into the fan circulation pipe, and a first level sensor and a second level sensor for detecting the amount of overflow powder in the overflow powder cans. The overflow powder screening mechanism includes a screening storage tank for storing powder to be screened, a linear screen for screening powder by an ultrasonic generator, a new powder cart for storing the screened powder, a large particle tank for storing large-diameter screened powder, and a third level sensor and a fourth level sensor for monitoring the material level of the screening storage tank and the new powder cart, respectively. An oxygen replacement mechanism includes a first to a fifth filling control valve for introducing inert gas, a first to a fifth exhaust control valve for discharging inert gas, and an oxygen detection device for detecting the oxygen content in the overflow tank, the filter, and the linear sieve, respectively. The screening control module includes a first control unit for determining whether to open or close the second pneumatic butterfly valve and the fourth pneumatic butterfly valve based on the powder volume in the overflow tank, and a second control unit for determining the wind speed or ultrasonic frequency in the screening pipeline based on the material level in the new powder cart and the screening storage tank. The gas replacement control module includes a third control unit for determining gas replacement based on the result that the oxygen detection device detects data that is greater than or equal to a preset oxygen content safety threshold, and a fourth control unit for adjusting the pressure of the powder delivery pipeline. The fan unit is used to output high-pressure air to transport powder in a closed-loop pipeline and adjust the air volume according to the powder volume. A cyclone separation assembly, comprising a first cyclone separator and a second cyclone separator for separating powder from air.

2. The 3D printer powder turnover auxiliary equipment according to claim 1, characterized in that, 3D printer powder turnover auxiliary equipment also includes: The fan duct filtration module includes a filter chamber located above the fan duct. The filter chamber contains a filter used to filter out small amounts of powder that are not completely separated in the cyclone separator, providing a clean environment for the fan inlet. Differential pressure detectors are installed on the inner and outer sides of the filter to detect filter blockage in real time and perform backflushing based on the result that the detected differential pressure is greater than a preset differential pressure threshold. A recovery tank is installed at the bottom of the filter chamber to collect the filtered powder.

3. The 3D printer powder turnover auxiliary equipment according to claim 2, characterized in that, 3D printer powder turnover auxiliary equipment also includes: The residual material calculation unit is used to calculate whether there is enough powder in the first cyclone separator after each powder feeding process. In response to the powder in the first cyclone separator being lower than the preset lower limit value, the tenth pneumatic butterfly valve is opened to send the powder from the new powder car into the first cyclone separator.

4. The 3D printer powder turnover auxiliary equipment according to claim 3, characterized in that, The overflow powder collection mechanism determines to close the first pneumatic butterfly valve and open the second pneumatic butterfly valve based on the result that the volume of powder in the first overflow powder tank is greater than or equal to 60% of the capacity of the first overflow powder tank, and determines to close the second pneumatic butterfly valve and open the first pneumatic butterfly valve based on the result that the volume of powder in the first overflow powder tank is less than 60% of the capacity of the first overflow powder tank. Furthermore, the overflow powder collection mechanism determines to close the third pneumatic butterfly valve and open the fourth pneumatic butterfly valve based on the result that the powder volume in the second overflow powder tank is greater than or equal to 60% of the capacity of the second overflow powder tank, and determines to close the fourth pneumatic butterfly valve and open the third pneumatic butterfly valve based on the result that the powder volume in the second overflow powder tank is less than 60% of the capacity of the second overflow powder tank.

5. The 3D printer powder turnover auxiliary equipment according to claim 4, characterized in that, The overflow powder collection mechanism determines the powder delivery volume based on the difference between the detection data of the first level sensor and the second level sensor at the start and end of the powder delivery operation. The gas replacement control module determines the total amount of gas in the powder delivery pipeline based on the powder delivery volume and a preset solid-gas ratio, and inputs and discharges inert gas into the powder delivery pipeline to maintain the internal pressure of the pipeline within a preset range.

6. The 3D printer powder turnover auxiliary equipment according to claim 5, characterized in that, The screening control module determines to open the eighth pneumatic butterfly valve connected to it and start the screening operation based on the material level sensor inside the screening storage tank detecting that the material level has reached 60% of the total capacity.

7. The 3D printer powder turnover auxiliary equipment according to claim 6, characterized in that, The screening control module determines the real-time screening speed based on the difference between the decrease in material level detected by the third material level sensor and the increase in material level detected by the fourth material level sensor during the screening operation. The gas displacement control module adjusts the internal pressure of the screening pipeline or the ultrasonic frequency based on the real-time screening speed.

8. The 3D printer powder turnover auxiliary equipment according to claim 7, characterized in that, The screening control module determines to reduce the ultrasonic frequency based on the result that the real-time screening speed is greater than the preset screening speed upper limit; the gas replacement control module determines to increase the air velocity inside the screening pipeline based on the result that the real-time screening speed is less than the preset screening speed lower limit. The decrease in ultrasonic frequency is positively correlated with the product of the ratio of the real-time screening speed to the preset screening speed upper limit and the first adjustment coefficient, and the increase in wind speed inside the screening pipeline is positively correlated with the product of the ratio of the real-time screening speed to the preset screening speed upper limit and the second adjustment coefficient.

9. The 3D printer powder turnover auxiliary equipment according to claim 8, characterized in that, When the first cyclone separator receives the 3D printer's operating command, it opens the sixteenth pneumatic butterfly valve connected to it to supply powder to the 3D printer.

10. The 3D printer powder turnover auxiliary equipment according to claim 9, characterized in that, The filter differential pressure detector detects the pressure difference between the outside and inside of the filter when the fan unit is running. Based on the result that the differential pressure detection data is greater than or equal to the preset differential pressure threshold, it determines to suspend the current operation and open the backflush canister. The powder is blown into the inside of the filter by the compressed inert gas in the backflush canister, and the powder layer attached to the outside of the filter is blown off.

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