Powder feeding device and powder feeding method for manufacturing three-dimensional objects

Abstract

A powder feeding device and a powder feeding method for manufacturing three-dimensional objects, wherein the powder feeding device comprises: a powder storage tank, a powder feeding hopper, a powder feeding box, a powder feeding shaft, a first gear, a second gear, a driving mechanism and a control system, the powder storage tank is provided with at least one first upper material level switch and a first lower material level switch from top to bottom, and a butterfly valve is provided at the bottom of the powder feeding hopper, which is used to control whether the powder falls into the powder storage tank under the control of the control system; one end of the powder feeding shaft is connected to the first gear, the second gear is connected to the driving mechanism, and the first gear is meshed with the second gear. When the driving mechanism drives the second gear to rotate, it drives the first gear to rotate, thereby driving the powder feeding shaft to rotate, so that the powder in the powder storage tank falls to the powder feeding box under the rotation of the powder feeding shaft, and falls to the powder feeding position through the outlet of the powder feeding box. The powder feeding device and the powder feeding method for manufacturing three-dimensional objects of the present invention have a stable rotation speed, a stable and smooth powder discharging rate, and a stable gear transmission.

Description

Technical Field

[0001] The present invention relates to the technical field of three-dimensional object manufacturing, and in particular to a powder feeding device and a powder feeding method for manufacturing three-dimensional objects. Background Art

[0002] As one of the additive manufacturing technologies, selective laser sintering technology has the following basic working process: the powder feeding device delivers a certain amount of powder to the work surface, the powder spreading device spreads a layer of powder material on the upper surface of the formed part of the forming cylinder, and the galvanometer system controls the laser to scan the solid part of the powder layer according to the cross-sectional contour of the layer, so that the powder melts and bonds with the formed part below; when a layer of cross section is sintered, the working table of the forming cylinder drops by one layer, and the powder spreading device moves to the powder feeding device, which delivers a certain amount of powder to the work surface, and the powder spreading device spreads a layer of uniform and dense powder on it, and scans and sinters a new layer of cross section, and after several layers of scanning and superposition, the entire prototype manufacturing is completed.

[0003] In the prior art, powder feeding devices are currently generally divided into upper powder feeding and lower powder feeding methods. The upper powder feeding includes a powder feeding hopper, a powder storage tank body, and a powder feeding shaft arranged inside the powder storage tank body. The powder in the groove falls through the groove on the powder feeding shaft and the rotation of the powder feeding shaft to complete the powder feeding. This upper powder feeding method has the advantages of compact structure and the ability to add raw material powder at any time, making it widely used in additive manufacturing equipment. However, this upper powder feeding method also has the following disadvantages: when the fluidity of the powder used is poor, the powder will be intermittent and not smooth, so that the amount of powder falling to the front end of the powder spreading device is inconsistent on the left and right, which will cause local powder shortage on the printing surface when spreading the powder; moreover, the raw material replenishment from the powder hopper to the box body is not timely, resulting in a lack of powder feeding, which in turn affects the stability of powder feeding and work efficiency. Summary of the invention

[0004] Based on this, the present invention provides a powder feeding device and a powder feeding method for manufacturing three-dimensional objects, which have solved the technical problems of the upper powder feeding method in the prior art, which leads to local powder shortage on the printing surface due to poor powder fluidity; and the powder is not replenished in time, thus affecting the powder feeding stability and work efficiency.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a powder feeding device for manufacturing three-dimensional objects, comprising: a powder storage tank, at least one powder feeding hopper arranged on the powder storage tank, a powder feeding box arranged under the powder storage tank, a powder feeding rotating shaft located in the powder feeding box and arranged at the bottom opening of the powder storage tank and tightly matched with the bottom opening, a first gear, a second gear, a driving mechanism and a control system, wherein the powder storage tank is provided with at least one first upper material level switch and at least one first lower material level switch from top to bottom, and a butterfly valve is provided at the bottom of the powder feeding hopper for controlling whether the powder falls into the powder storage tank under the control of the control system; one end of the powder feeding rotating shaft is connected to the first gear, and the second gear is connected to the driving mechanism, and the first gear is meshed with the second gear. When the driving mechanism drives the second gear to rotate, it drives the first gear to rotate, thereby driving the powder feeding rotating shaft to rotate, so that the powder in the powder storage tank falls to the powder feeding box under the rotation of the powder feeding rotating shaft, and falls to the powder feeding position through the outlet of the powder feeding box.

[0006] As a further preferred embodiment of the present invention, when there are two powder feeding hoppers and they are respectively located on both sides above the powder storage tank, there are two first upper material level switches and two first lower material level switches and they are respectively arranged on both sides of the powder storage tank.

[0007] As a further preferred embodiment of the present invention, the powder feeding hopper is provided with a second upper material level switch and a second lower material level switch in sequence from top to bottom.

[0008] As a further preferred embodiment of the present invention, the powder feeding device further comprises a guide groove, and the guide groove is communicated with the outlet of the powder feeding box.

[0009] As a further preferred embodiment of the present invention, the driving mechanism is a servo motor.

[0010] The present invention also provides a powder feeding method of a powder feeding device for manufacturing a three-dimensional object, comprising the following steps:

[0011] The control system controls the butterfly valve of at least one powder feeding hopper to open so that the powder in the at least one powder feeding hopper falls into the powder storage tank, and the butterfly valve closes after a preset time;

[0012] When the control system receives a powder delivery request instruction, the control system controls the driving mechanism to drive the second gear to rotate by a preset amount, and the rotation of the second gear drives the first gear to rotate, thereby driving the powder delivery shaft to rotate, so that the powder in the powder storage tank falls to the powder delivery box under the rotation of the powder delivery shaft, and falls to the powder delivery position through the outlet of the powder delivery box;

[0013] When the powder in the powder storage tank is gradually consumed and at least one first discharge level switch detects a lack of powder, the butterfly valves of all powder feeding hoppers are controlled to open so that the powder in at least one powder feeding hopper falls into the powder storage tank, and the butterfly valves are closed after a preset time.

[0014] As a further preferred embodiment of the present invention, the method further comprises:

[0015] Starting from each time the butterfly valve of the powder feeding hopper is closed, the number of times the powder in the powder storage tank falls to the powder feeding position is accumulated, and when the number reaches a set value, the butterfly valve of at least one powder feeding hopper is controlled to open, so that the powder in at least one powder feeding hopper falls into the powder storage tank, and the butterfly valve is closed after a preset time.

[0016] As a further preferred embodiment of the present invention, the preset time is 3s.

[0017] As a further preferred embodiment of the present invention, the method further comprises:

[0018] In the process that powder of at least one powder feeding hopper falls into the powder storage tank, when at least one first upper material level switch of the powder storage tank detects powder, the butterfly valve of the powder feeding hopper is controlled to be closed.

[0019] As a further preferred embodiment of the present invention, the method further comprises:

[0020] In the process of powder from the powder feeding hopper falling into the powder storage tank, when the second lower level switch of the powder feeding hopper detects a lack of powder, the control system sends a request to add powder to the external closed-loop powder feeding system, so that the closed-loop powder feeding system adds powder to the powder feeding hopper; and when the second upper level switch signal of the powder feeding hopper detects powder, the control system sends a request to stop adding powder to the external closed-loop powder feeding system, so that the closed-loop powder feeding system stops adding powder to the powder feeding hopper.

[0021] The powder feeding device for manufacturing three-dimensional objects of the present invention comprises: a powder storage tank, at least one powder feeding hopper arranged on the powder storage tank, a powder feeding box arranged under the powder storage tank, a powder feeding rotating shaft located in the powder feeding box and arranged at the bottom opening of the powder storage tank and tightly matched with the bottom opening, a first gear, a second gear, a driving mechanism and a control system, wherein the powder storage tank is provided with at least one first upper material level switch and at least one first lower material level switch in sequence from top to bottom, and a butterfly valve is provided at the bottom of the powder feeding hopper for controlling whether the powder falls into the powder storage tank under the control of the control system; the powder feeding One end of the rotating shaft is connected to the first gear, and the second gear is connected to the driving mechanism. The first gear is meshed with the second gear. When the driving mechanism drives the second gear to rotate, it drives the first gear to rotate, thereby driving the powder feeding rotating shaft to rotate, so that the powder in the powder storage tank falls to the powder feeding box under the rotation of the powder feeding rotating shaft, and falls to the powder feeding position through the outlet of the powder feeding box. The present invention adopts the first gear to directly connect the powder feeding rotating shaft to rotate, so the rotation speed is stable, the powder feeding rate is stable and smooth, and the powder shortage caused by intermittent powder feeding can be effectively avoided. Moreover, the gear transmission is smooth and stable, and the transmission effect rate is high.

[0022] The powder feeding method of the powder feeding device for manufacturing three-dimensional objects of the present invention has all the beneficial effects of the above-mentioned powder feeding device because it has the powder feeding device for manufacturing three-dimensional objects of the above-mentioned technical solution. Moreover, the powder feeding method includes: the control system controls the butterfly valve of at least one powder feeding hopper to open so that the powder in the at least one powder feeding hopper falls into the powder storage tank, and the butterfly valve is closed after a preset time; when the control system receives a powder feeding request instruction, the control system controls the driving mechanism to drive the second gear to rotate a preset rotation amount, and the rotation of the second gear drives the first gear to rotate, and then drives the powder feeding shaft to rotate, so that the powder in the powder storage tank falls under the rotation of the powder feeding shaft. To the powder feeding box, and fall to the powder feeding position through the outlet of the powder feeding box; when the powder amount in the powder storage tank is gradually consumed to the point where at least one first lower material level switch detects a lack of powder, the butterfly valves of all powder feeding hoppers are controlled to open, so that the powder in at least one powder feeding hopper falls into the powder storage tank, and the butterfly valves are closed after a preset time, so that the method can accurately control the amount of powder falling in each layer by continuously and repeatedly accurately controlling the rotation amount and rotation speed of the execution part of the powder feeding device; and combined with the upper and lower material level switches, the powder consumption in the powder feeding hopper and the powder storage tank is stable, and the powder replenishment is fast and timely, so that the method can greatly improve the fluency and stability of the upper powder feeding method while ensuring the powder feeding amount and powder feeding efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic structural diagram of an embodiment of a powder feeding device for manufacturing a three-dimensional object provided by the present invention;

[0024] Figure 2 for Figure 1 Left view of

[0025] Figure 3 for Figure 1 A top view of

[0026] Figure 4 for Figure 1 A partial cross-sectional view of .

[0027] Numbers in the figure: 1, left powder feeding hopper; 2, second upper material level switch; 3, second lower material level switch; 4, butterfly valve; 5, powder storage tank; 6, upper left material level switch; 7, upper right material level switch; 8, lower left material level switch;

[0028] 9. Lower right material level switch; 10. First gear; 11. Guide groove; 12. Second gear; 13. Right powder hopper; 14. Powder box; 15. Servo motor; 16. Powder shaft. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are provided. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0031] like Figure 1-Figure 4 As shown, the powder feeding device for manufacturing a three-dimensional object includes: a powder storage tank 5, at least one powder feeding hopper arranged on the powder storage tank 5, a powder feeding box 14 arranged under the powder storage tank 5, a powder feeding rotating shaft 16 located in the powder feeding box 14 and arranged at the bottom opening of the powder storage tank 5 and tightly matched with the bottom opening, a first gear 10, a second gear 12, a driving mechanism and a control system, the powder storage tank 5 is provided with at least one first upper material level switch and at least one first lower material level switch from top to bottom, and the bottom of the powder feeding hopper is provided with a butterfly valve 4 , used to control whether the powder falls into the powder storage tank 5 under the control of the control system; one end of the powder delivery shaft 16 is connected to the first gear 10, the second gear 12 is connected to the driving mechanism, the first gear 10 is meshed with the second gear 12, when the driving mechanism drives the second gear 12 to rotate, the first gear 10 is driven to rotate, thereby driving the powder delivery shaft 16 to rotate, so that the powder in the powder storage tank 5 falls to the powder delivery box 14 under the rotation of the powder delivery shaft 16, and falls to the powder delivery position through the outlet of the powder delivery box 14. The driving mechanism can be a servo motor 15, of course, it can also be other devices with driving functions, which are not listed here one by one.

[0032] Due to the poor fluidity of the powder in the powder storage tank 5 during the printing process, as the powder is continuously consumed, the powder level in the powder storage tank 5 is prone to be inconsistent; in the prior art, only a set of upper and lower level switches are set in the middle upper and lower positions in the powder storage tank 5, and in the actual printing process, the material level on the left side of the powder storage tank 5 is often low and the material level on the right side is high, while the lower material position set in the middle still shows that there is material, resulting in the failure to replenish the powder on the left side of the powder storage tank 5 in time. When the powder is lowered, there will be insufficient powder on the left side of the scraper for spreading the powder, while the powder on the right side is sufficient. When spreading the powder, there will be a shortage of powder on the left side of the printing surface; and in the process of the left and right powder feeding hoppers 13 quickly replenishing powder into the powder storage tank 5, the prior art cannot ensure that the powder replenishment speed of the two powder hoppers remains consistent. If an intermediate loading level is set, this will result in that the high material levels on the left and right sides of the powder storage tank 5 cannot be reached at the same time. In severe cases, one side of the powder will be filled and overflow, while the right side will only be filled to the middle position of the powder storage tank 5. At this time, the intermediate loading level signal is 0, and the butterfly valve 4 of the powder feeding hopper is not closed in time, resulting in the powder overflowing on this side and blocking the powder feeding pipeline below the butterfly valve 4. In order to solve this technical problem, preferably, when there are two powder feeding hoppers and they are respectively located on both sides above the powder storage tank 5, there are two first loading level switches and two first loading level switches, which are respectively set on both sides of the powder storage tank 5, so that the powder discharge of each powder feeding hopper can be accurately controlled to achieve accurate powder discharge.

[0033] In order to better control the powder adding status of the powder feeding hopper, the powder feeding hopper is provided with a second upper level switch 2 and a second lower level switch 3 from top to bottom in sequence, which is used for sending a request for powder adding instruction to the external closed-loop powder feeding system when the second lower level switch 3 of the powder feeding hopper detects a lack of powder during the process of the powder in the powder feeding hopper falling to the powder storage tank 5, so that the closed-loop powder feeding system adds powder to the powder feeding hopper; and when the signal of the second upper level switch 2 of the powder feeding hopper detects powder, the control system sends a request to stop adding powder instruction to the external closed-loop powder feeding system, so that the closed-loop powder feeding system stops adding powder to the powder feeding hopper.

[0034] like Figure 1 As shown, preferably, in order to prevent the powder from flying when falling and polluting the environment, the powder feeding device further includes a guide groove 11 , and the guide groove 11 is communicated with the outlet of the powder feeding box 14 .

[0035] As a further preferred solution of the present invention, the driving mechanism is a servo motor 15 .

[0036] The present invention also provides a powder feeding method of a powder feeding device for manufacturing a three-dimensional object, comprising the following steps:

[0037] The control system controls the butterfly valve 4 of at least one powder feeding hopper to open, so that the powder in at least one powder feeding hopper falls into the powder storage tank 5, and the butterfly valve 4 closes after a preset time;

[0038] When the control system receives a powder delivery request instruction, the control system controls the driving mechanism to drive the second gear 12 to rotate by a preset amount. The rotation of the second gear 12 drives the first gear 10 to rotate, and then drives the powder delivery shaft 16 to rotate, so that the powder in the powder storage tank 5 falls to the powder delivery box 14 under the rotation of the powder delivery shaft 16, and falls to the powder delivery position through the outlet of the powder delivery box 14;

[0039] When the powder in the powder storage tank 5 is gradually consumed until at least one first discharge level switch detects a lack of powder, the butterfly valves 4 of all powder feeding hoppers are controlled to open so that the powder in at least one powder feeding hopper falls into the powder storage tank 5, and the butterfly valves 4 are closed after a preset time.

[0040] In order to prevent one of the two material discharge level switches from failing during printing, or when the powder fluidity is poor (powder will stick to the first material discharge level switch and the feedback will always be 1, i.e., there is material, which will cause the first material discharge level switch to fail), the method further includes:

[0041] Starting from each time the butterfly valve 4 of the powder feeding hopper is closed, the number of times the powder in the powder storage tank 5 falls to the powder feeding position is accumulated, and when the number reaches the set value, the butterfly valve 4 of at least one powder feeding hopper is controlled to open, so that the powder in at least one powder feeding hopper falls to the powder storage tank 5, and the butterfly valve 4 is closed after a preset time. In this way, it is ensured that there is actually material in the first material discharge position on both sides of the powder storage tank 5, thereby ensuring that there will be no shortage of powder each time the powder is discharged and the amount of powder discharged is balanced on the left and right. It should be noted that the set value here is obtained by the designer through multiple experiments. The powder in the powder storage tank 5 can meet the powder feeding amount for how many times when reaching the first material loading switch position, and the powder feeding amount of each layer is equal to the amount of powder in a layer of thickness of the workpiece to be printed, that is, how many times the powder feeding request instructions can be realized.

[0042] Specifically, the above-mentioned preset time is 3s, which is obtained by the designer through multiple experiments. Of course, it can also be specifically set according to the powder feeding speed and the volume of the powder storage tank 5. That is to say, after the preset time, it is basically guaranteed that the powder storage tank 5 is filled with powder, that is, the powder feeding amount of the set number of times can be met.

[0043] Preferably, the method further comprises:

[0044] In the process of powder from at least one powder feeding hopper falling into the powder storage tank 5, when at least one first upper material level switch of the powder storage tank 5 detects powder, the butterfly valve 4 of the powder feeding hopper is controlled to be closed. In this way, the butterfly valve 4 of each powder feeding hopper is controlled separately, thereby avoiding the different powder dropping speeds of multiple butterfly valves 4, which will cause the high material levels on the left and right sides of the powder storage tank 5 to not reach at the same time. In serious cases, one side of the powder will be filled and overflow, while the right side will only be filled to the middle position of the powder storage tank 5. At this time, the middle upper material level signal is 0, and the butterfly valve 4 of the powder feeding hopper is not closed in time, resulting in the powder overflowing on this side and blocking the powder feeding pipeline below the butterfly valve 4.

[0045] In order to ensure the powder feeding amount and powder feeding efficiency while further improving the fluency and stability of the upper powder feeding method, the method further includes:

[0046] In the process of powder from the powder feeding hopper falling into the powder storage tank 5, when the second lower level switch 3 of the powder feeding hopper detects a lack of powder, the control system sends a request to add powder to the external closed-loop powder feeding system, so that the closed-loop powder feeding system adds powder to the powder feeding hopper; and when the second upper level switch 2 signal of the powder feeding hopper detects powder, the control system sends a request to stop adding powder to the external closed-loop powder feeding system, so that the closed-loop powder feeding system stops adding powder to the powder feeding hopper.

[0047] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the technical solution of the present invention is described in detail in the form of an embodiment below.

[0048] 1. When the powder spreading device is located at the limit position close to the powder feeding position (directly below the powder falling guide groove 11), the powder spreading device starts to spread powder and moves to the powder feeding position, and connects the first gear 10 of the powder feeding shaft 16. The servo motor 15 drives the second gear 12 to rotate and accurately controls its rotation amount: the shaft end of the servo motor 15 is connected to the second gear 12 through a first-stage reducer with a reduction ratio of 1:9, and the second gear 12 is connected to the first gear 10 through a first-stage gear reduction ratio of 1:2, and the first gear 10 is directly connected to the powder feeding shaft 16; for example, when the powder feeding amount required for the current layer printing is converted to a rotation angle of 30° for the powder feeding shaft 16, the shaft end of the servo motor 15 is controlled to rotate 2×9×30°=540°. It can ensure that the amount of powder delivered by the powder delivery shaft 16 is accurately controlled, and then by using the optimal rotation speed of 700rpm of the servo motor 15 obtained by the test, the speed of the powder delivery shaft 16 to deliver powder is controlled at 38.89rpm. This powder delivery rotation speed can ensure the powder delivery efficiency of the powder delivery shaft 16 (moderate speed), and can also ensure that when the fluidity of the powder is poor, the powder is transported to the guide groove 11 by the tangential driving force generated by the active rotation of the powder delivery shaft 16. Since the linear speed of each point along the axial direction of the powder delivery shaft 16 is consistent, the tangential driving force of each point is consistent, thereby ensuring that the powder delivery speed to the guide groove 11 is consistent, and the powder delivery amount falling to the scraper powder spreading side per unit time is highly consistent and balanced on the left and right.

[0049] 2. During the powder feeding process, when the amount of powder in the powder storage tank 5 is gradually consumed until the signal of one or two first material discharge level switches of the box body is 0 (i.e. no powder is detected or powder shortage is detected), or when the cumulative number of times the powder in the powder storage tank 5 falls to the powder feeding position (i.e. the powder feeding shaft 16 drops powder) (the cumulative value increases by 1 each time the powder falls) reaches the set value, the butterfly valve 4 of the left powder feeding hopper 1 and the butterfly valve 4 of the right powder feeding hopper 13 are immediately opened to quickly replenish powder into the powder storage tank 5, the butterfly valve 4 is closed after being opened for 3 seconds, and the cumulative number of times the powder feeding shaft 16 drops powder is reset to zero. The setting function of this cumulative number of powder drops (given according to the design capacity and powder drop test verification) is a safety function to prevent one of the two first material drop level switches from failing during printing. Generally, when the powder fluidity is poor (powder will stick to the first material drop level switch, and it will always feedback as 1, that is, there is material), the cumulative number of powder drops control function can ensure that there is actually material in the left and right material drop levels in the powder storage tank 5, thereby ensuring that there will be no shortage of powder each time the powder is dropped and the powder drop amount is balanced on the left and right.

[0050] 3. During the process of the left powder hopper 1 and the right powder hopper 13 quickly replenishing powder to the powder storage tank 5, when the signal of any upper material level switch (including the upper left material level switch 6 and the upper right material level switch 7) of the box body is 1, the butterfly valve 4 on the same side of the upper material level switch is closed, and the cumulative value of the number of powder drops of the powder delivery shaft 16 is cleared and maintained at 0. After that, as the amount of powder in the box body is consumed, when the signals of the upper left material level switch 6 and the upper right material level switch 7 in the box body are both 0, the cumulative value of the number of powder drops of the powder delivery shaft 16 starts to accumulate again. Although this method cannot ensure that the powder on both sides of the powder storage tank 5 is filled at the same time, it can prevent the powder on one side from overflowing and blocking the powder delivery pipeline of the butterfly valve 4, and can ensure that the upper left material level switch 6 and the upper right material level switch 7 in the powder storage tank 5 detect the presence of material, and the powder storage tank 5 is not too full, so that the amount of powder dropped by the powder delivery shaft 16 is always sufficient and continuous, thereby ensuring the smoothness and stability of powder delivery.

[0051] 4. During the powder feeding process, when the signal of any lower level switch (including the upper left level switch 6 and the upper right level switch 7) in the left powder feeding hopper 1 and the right powder feeding hopper 13 is 0 (i.e., no powder is detected), the powder feeding request instruction is automatically activated to the closed-loop powder feeding system, and the powder amount in the powder feeding hopper is quickly replenished; when the signals of the upper left level switch 6 and the upper right level switch 7 of the left powder feeding hopper 1 and the right powder feeding hopper 13 are all 1 (i.e., powder is detected), the powder feeding request instruction is reset, and the closed-loop powder feeding system immediately stops replenishing powder into the powder hopper.

[0052] 5. When the powder spreading device reaches the limit position close to the powder feeding position again, the above powder feeding actions (1) (2) (3) (4) are repeated.

[0053] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A powder feeding method of a powder feeding device for manufacturing a three-dimensional object, characterized in that: The powder feeding device for manufacturing three-dimensional objects comprises: a powder storage tank, at least one powder feeding hopper arranged on the powder storage tank, a powder feeding box arranged under the powder storage tank, a powder feeding rotating shaft located in the powder feeding box and arranged at the bottom opening of the powder storage tank and tightly matched with the bottom opening, a first gear, a second gear, a driving mechanism and a control system, wherein the powder storage tank is provided with at least one first upper material level switch and at least one first lower material level switch in sequence from top to bottom, and a butterfly valve is provided at the bottom of the powder feeding hopper; one end of the powder feeding rotating shaft is connected to the first gear, the second gear is connected to the driving mechanism, and the first gear is meshed with the second gear; the powder feeding method comprises the following steps: The control system controls the butterfly valve of at least one powder feeding hopper to open so that the powder in the at least one powder feeding hopper falls into the powder storage tank, and the butterfly valve closes after a preset time; When the control system receives a powder delivery request instruction, the control system controls the driving mechanism to drive the second gear to rotate by a preset amount, and the rotation of the second gear drives the first gear to rotate, thereby driving the powder delivery shaft to rotate, so that the powder in the powder storage tank falls to the powder delivery box under the rotation of the powder delivery shaft, and falls to the powder delivery position through the outlet of the powder delivery box; When the powder in the powder storage tank is gradually consumed until at least one first discharge level switch detects a lack of powder, the butterfly valves of all powder feeding hoppers are controlled to open, so that the powder in at least one powder feeding hopper falls into the powder storage tank, and the butterfly valves are closed after a preset time; wherein, Starting from each time the butterfly valve of the powder feeding hopper is closed, the number of times the powder in the powder storage tank falls to the powder feeding position is accumulated, and when the number reaches a set value, the butterfly valve of at least one powder feeding hopper is controlled to open, so that the powder in at least one powder feeding hopper falls into the powder storage tank, and the butterfly valve is closed after a preset time.

2. The powder feeding method of the powder feeding device for manufacturing three-dimensional objects according to claim 1, characterized in that: The preset time is 3s.

3. The powder feeding method of the powder feeding device for manufacturing three-dimensional objects according to claim 2, characterized in that: The method further comprises: In the process that powder of at least one powder feeding hopper falls into the powder storage tank, when at least one first upper material level switch of the powder storage tank detects powder, the butterfly valve of the powder feeding hopper is controlled to be closed.

4. The powder feeding method of a powder feeding device for manufacturing a three-dimensional object according to any one of claims 1 to 3, characterized in that: The method further comprises: In the process of powder from the powder feeding hopper falling into the powder storage tank, when the second lower level switch of the powder feeding hopper detects a lack of powder, the control system sends a request to add powder to the external closed-loop powder feeding system, so that the closed-loop powder feeding system adds powder to the powder feeding hopper; and when the second upper level switch signal of the powder feeding hopper detects powder, the control system sends a request to stop adding powder to the external closed-loop powder feeding system, so that the closed-loop powder feeding system stops adding powder to the powder feeding hopper.

Images