Powder supply method, three-dimensional printing method and three-dimensional printing system

Abstract

The invention discloses a powder supply method, a three-dimensional printing method and a three-dimensional printing system. The powder supply method is used for supplying powder used for three-dimensional printing to a powder laying mechanism so that the powder laying mechanism can lay the powder to a construction platform in the laying direction; the two sides, in the laying direction, of the construction platform are each provided with a powder supply groove and a powder supply piece, the powder supply grooves are used for containing powder, and the powder supply pieces are located in the corresponding powder supply grooves and ascend and descend relative to the powder supply grooves. When powder is supplied every time, the powder supply piece on the powder supply side supplies powder through lifting, and the powder supply piece on the powder receiving side receives powder overflowing from the construction platform through descending; the powder supply side and the powder receiving side are the side where the powder laying mechanism firstly passes through the powder supply groove and the side where the powder laying mechanism later passes through the powder supply groove during laying. The powder supply method is adopted in the powder supply process in the three-dimensional printing method. The three-dimensional printing system is used for realizing the powder supply method. By the adoption of the technical scheme, compared with the prior art, the amount of powder needing to be carried by the construction unit is smaller.

Description

Technical Field

[0001] The present application relates to the field of three-dimensional printing, and in particular to a powder supply method, a three-dimensional printing method and a three-dimensional printing system. Background Art

[0002] A three-dimensional printing system in the prior art includes a building unit and a printer. The building unit includes a building body, a building platform and two powder supply parts. The building body is provided with a building slot, two powder supply slots and two overflow powder slots. The building slot is located between the two powder supply slots along a first direction, and the powder supply slot is located between the building platform and the corresponding overflow powder slot along the first direction. The building platform is located in the building slot and rises and falls relative to the building body, and the powder supply part is located in the powder supply slot and rises and falls relative to the building body. The building slot and the building platform that descends layer by layer together enclose a building space for forming a three-dimensional printed part. The powder supply part supplies powder by lifting. The powder supply slot is used to accommodate powder as a printing material. The overflow powder slot is used to accommodate powder overflowed from the building platform during laying. The printer includes a printer body, a powder spreading mechanism, a printing mechanism and a controller. The printer body is suitable for the attachment of the building unit. The powder spreading mechanism reciprocates relative to the printer body along the laying direction to lay the powder supplied by the powder supply part on the building platform. When the building unit is attached to the printer body, the laying direction is the same as the first direction. The printing mechanism is used to print the powder on the building platform. Specifically, the printing mechanism is provided with an injection head and a flux lamp. The injection head is used to selectively spray flux onto the powder on the building platform, and the flux lamp is used to sinter the powder sprayed with flux. The printing mechanism moves relative to the printer body along the printing direction. Generally, the printing direction is perpendicular to the laying direction. The controller is connected to the powder laying mechanism and the printing mechanism by signal. When the building unit is attached to the printer body, the controller is connected to the building platform and the two powder supply parts by signal. The signal connection here can be an electrical connection or a wireless signal connection. The controller realizes layer-by-layer printing by controlling the building platform, the powder supply part, the powder laying mechanism and the printing mechanism. Specifically, when each layer is printed, it includes a powder supply step, a laying step and a printing step in sequence. The powder supply step includes a building platform descending process and a powder supply process. The building platform descending process and the powder supply process can be carried out in parallel or in sequence. When they are carried out in sequence, there is no distinction in order. During the descent of the build platform, the controller controls the build platform to descend a first set distance. During the powder supply process, the controller controls the powder supply part near the powder spreading mechanism to lift upward. In the laying step, the controller controls the powder spreading mechanism to move along the laying direction, passing through two powder supply slots in succession, and laying the powder on the build platform. The powder overflowing from the build platform eventually falls into the overflow powder slot. In the printing step, the controller controls the printing mechanism to move along the printing method. At the same time, the nozzle selectively sprays flux, and the flux lamp sintering the powder sprayed with flux.

[0003] The defect of the above technical solution is that since the powder overflowing from the building platform enters the powder overflow tank, and the powder in the overflow powder tank cannot re-enter the powder supply tank, the amount of powder that the building unit needs to carry is far greater than the amount of powder actually required for three-dimensional printing. Summary of the invention

[0004] The purpose of the present application is to overcome the above-mentioned defects or problems existing in the background technology and to provide a powder supply method, a three-dimensional printing method and a three-dimensional printing system, wherein, compared with the prior art, the amount of powder that a building unit needs to carry is less than that of the prior art.

[0005] In order to achieve the above purpose, the following technical solutions are adopted:

[0006] The first technical scheme relates to a powder supply method, which is used to supply powder for three-dimensional printing to a powder spreading mechanism, so that the powder spreading mechanism spreads the powder onto a building platform along a laying direction; a powder supply trough and a powder supply member are provided on both sides of the building platform along the laying direction, the powder supply trough is used to accommodate powder, and the powder supply member is located in the corresponding powder supply trough and rises and falls relative to the powder supply trough; each time powder is supplied, the powder supply member on the powder supply side supplies powder by lifting, and the powder supply member on the powder receiving side receives powder overflowed from the building platform by descending; the powder supply side is the side where the powder supply trough that the powder spreading mechanism passes first when laying is located, and the powder receiving side is the side where the powder supply trough that the powder spreading mechanism passes later when laying is located.

[0007] The second technical solution is based on the first technical solution, wherein each time powder is supplied, the lifting distance of the powder supply member on the powder supply side is determined according to the amount of powder received by the corresponding powder supply slot when the last powder laying mechanism laid a layer of powder.

[0008] The third technical solution is based on the second technical solution, wherein each time powder is supplied, the powder supply member on the receiving side descends a consistent distance.

[0009] The fourth technical solution is based on the third technical solution, wherein the amount of powder received by the powder supply trough when the powder laying mechanism lays a layer of powder is characterized by the spreading distance of the received powder along the laying direction; when the spreading distance is less than a threshold value, the lifting distance is the first distance; when the spreading distance is greater than the threshold value, the lifting distance is the second distance; when the spreading distance is equal to the threshold value, the lifting distance is the first distance or the second distance; the first distance is greater than the second distance.

[0010] The fifth technical solution is based on the fourth technical solution, wherein the spreading distance is the average value of the distance between the edge line formed by the powder received by the powder supply trough when the powder laying mechanism lays a layer of powder and the trough edge of the powder supply trough close to the building platform along the laying direction.

[0011] The sixth technical solution is based on the fifth technical solution, wherein the spreading distance is obtained by obtaining an image of the upper surface of the powder in the powder supply trough through an image acquisition device after the powder spreading mechanism spreads a layer of powder.

[0012] The seventh technical solution is based on the sixth technical solution, wherein the field of view of the image acquisition device covers the upper surfaces of the building platform and the two powder supply troughs.

[0013] The eighth technical solution relates to a three-dimensional printing method, which obtains a three-dimensional printed part by printing layer by layer; each layer printing sequentially includes a powder supply step, a laying step and a printing step; the powder supply step includes a building platform descending process and a powder supply process, the laying step is used to lay powder on the building platform, and the printing step is used to selectively sinter the powder laid on the building platform; the powder supply process adopts the powder supply method as described in any one of the first to fifth technical solutions.

[0014] The ninth technical scheme relates to a three-dimensional printing method, which obtains a three-dimensional printed part by printing layer by layer; each layer printing sequentially includes a powder supply step, a laying step, an image acquisition step and a printing step; the powder supply step includes a building platform descending process and a powder supply process, the laying step is used to lay powder on the building platform, the image acquisition step is used to obtain an image of the upper surface of the powder in the powder supply trough, and the printing step is used to selectively sinter the powder laid on the building platform; wherein, the powder supply process adopts the powder supply method as described in any one of the fourth to seventh, and the spreading distance is obtained by the image obtained when the previous layer is printed.

[0015] The tenth technical scheme relates to a three-dimensional printing system, which includes a building unit and a printer; the building unit includes a building body, a building platform and two powder supply parts; the building body is provided with a building groove and powder supply grooves located on both sides of the building groove, the building platform is located in the building groove and rises and falls relative to the building body, and the powder supply parts are located in the corresponding powder supply grooves and rise and fall relative to the building body; the printer includes a printer body, a powder spreading mechanism, an image acquisition device and a controller; the printer body is suitable for the attachment of the building unit, and the powder spreading mechanism reciprocates relative to the printer body along the laying direction; when the building unit is attached to the printer body, the laying direction is the same as the laying direction of the building groove and the powder supply groove, the image acquisition device is used to acquire the image of the upper surface of the powder in the building groove and the two powder supply grooves, and the controller is connected to the powder spreading mechanism, the image acquisition device, the building platform of the building unit attached to the printer body and the two powder supply parts by signal; the controller receives the image The acquisition device acquires an image and controls the movement of the powder spreading mechanism, the building platform and the two powder supply parts to realize layer-by-layer printing; when each layer is printed, the controller first controls the building platform to descend by a first set distance, and controls the powder supply part on the powder supply side to lift by a lifting distance and controls the powder supply part on the powder receiving side to descend by a second set distance; then controls the powder spreading mechanism to pass through the powder supply slot on the powder supply side and the powder supply slot on the powder receiving side in sequence along the laying direction; then controls the image acquisition device to acquire and receive the image; the controller acquires the spreading distance of the powder received in the powder supply slot on the receiving side along the laying direction according to the received image; when the first layer is printed, the lifting distance is the first distance; when each layer is printed thereafter, the lifting distance is determined according to the spreading distance acquired when the previous layer was printed, and when the spreading distance is less than a threshold, the lifting distance is the first distance; when the spreading distance is greater than the threshold, the lifting distance is the second distance; when the spreading distance is equal to the threshold, the lifting distance is the first distance or the second distance; the first distance is greater than the second distance.

[0016] The eleventh technical solution is based on the ninth technical solution, wherein the printer also includes a printing mechanism for printing powder on the building platform, and the controller is also connected to the printing mechanism signal; when each layer is printed, the controller controls the printing mechanism to print after receiving the image; the building body is also provided with two overflow powder troughs, and the two overflow powder troughs correspond to two powder supply troughs, and the powder supply trough is located between the building platform and the corresponding overflow powder trough along the laying direction.

[0017] Compared with the prior art, the above solution has the following beneficial effects:

[0018] In the first technical solution, the powder supply member on the powder receiving side is lowered to receive at least most of the powder overflowing from the building platform into the powder supply slot. Compared with the prior art in which the powder overflowing from the building platform is received into the overflow powder slot, at least most of the overflowed powder can be reused for laying on the building platform. Therefore, the amount of powder that the building unit needs to carry is less than that of the prior art.

[0019] In the second technical solution, the lifting distance of the powder supply part on the powder supply side is determined by the amount of powder received by the corresponding powder supply trough when the powder laying mechanism lays a layer of powder. Compared with the case where the lifting distance remains unchanged, the amount of powder overflowing from the building platform and falling into the overflow powder trough can be further reduced, thereby further reducing the amount of powder that the building unit needs to carry.

[0020] The third to fifth technical solutions are preferred implementations of the second technical solution. Under the premise that the powder supply member on the receiving side has a consistent descending distance, the amount of powder received by the powder supply slot when the powder laying mechanism lays the last layer of powder is characterized by the spreading distance. Compared with other calculation methods, the amount of calculation of the received powder amount can be reduced. In addition, the lifting distance is limited to the first distance and the second distance, which can optimize the control logic of the lifting distance and avoid the control logic being too complicated.

[0021] The sixth to seventh technical solutions, obtaining the spreading distance through the image acquired by the image acquisition device, are preferred implementations for measuring the spreading distance. This is mainly based on the fact that the received powder can form a clear edge line on the surface of the powder in the powder supply trough.

[0022] The eighth and ninth technical solutions have the technical effects of the technical solutions they refer to.

[0023] The tenth technical solution is a specific implementation method of the powder supply method defined in the sixth and seventh technical solutions.

[0024] The eleventh technical solution is to set up an overflow powder trough so that in case the powder overflowing from the building platform cannot be completely received by the powder supply trough on the powder receiving side, it can receive excess powder to avoid waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solution of the embodiment, the following briefly introduces the drawings required for use:

[0026] Figure 1 is a front view of a three-dimensional printing system in an embodiment;

[0027] Figure 2 for Figure 1 AA section view;

[0028] Figure 3 Schematic diagram of each step of printing for each layer.

[0029] Description of main reference numerals:

[0030] 1. 3D printing system; 100. build unit; 110. build body; 111. build slot; 112. powder supply slot; 113. powder overflow slot; 120. build platform; 130. powder supply unit; 200. printer; 210. printer body; 220. powder spreading mechanism; 230. printing mechanism; 231. jet head; 232. flux lamp; 240. image acquisition device. DETAILED DESCRIPTION

[0031] In the claims and the description, unless otherwise defined, the terms "first", "second" or "third", etc. are intended to distinguish different objects rather than to describe a specific order.

[0032] In the claims and the specification, unless otherwise defined, terms such as "center", "lateral", "longitudinal", "horizontal", "vertical", "top", "bottom", "inside", "outside", "up", "down", "front", "back", "left", "right", "clockwise", "counterclockwise" and the like indicating directions or positional relationships are based on the directions and positional relationships shown in the drawings and are only for the convenience of simplifying the description and do not imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction.

[0033] In the claims and the specification, unless otherwise defined, the term "fixed connection" or "fixed connection" should be understood in a broad sense, that is, any connection method in which there is no displacement relationship and relative rotation relationship between the two parties, that is to say, including non-detachable fixed connection, detachable fixed connection, integral connection and fixed connection through other devices or elements.

[0034] In the claims and the description, unless otherwise defined, the terms "includes", "has" and their variations mean "including but not limited to".

[0035] In the claims and the specification, unless otherwise defined, the term "provided with" means that the technical feature located thereafter is a part of the technical feature located therefor.

[0036] The technical solutions in the embodiments will be described clearly and completely below in conjunction with the accompanying drawings.

[0037] See also Figure 1 and Figure 2 , Figure 1 and Figure 2 The three-dimensional printing system 1 in the embodiment is shown. Figure 1 and Figure 2 As shown, the three-dimensional printing system 1 includes a building unit 100 and a printer 200 .

[0038] like Figure 2As shown, the building unit 100 includes a building body 110, a building platform 120 and two powder supply members 130. The building body 110 has wheels and is movable. The building platform 120 and the two powder supply members 130 are both installed in the building body 110. The building body 110 is respectively provided with a building slot 111, two powder supply slots 112 and two overflow powder slots 113 along the first direction. The building slot 111 is used to form a building space for a three-dimensional printed part. The powder supply slot 112 is used to accommodate powder as a printing material. The overflow powder slot 113 is used to accommodate powder overflowing from the building platform 120 and the powder supply slot 112. The two powder supply slots 112 and the two overflow powder slots 113 are arranged corresponding to each other. The building slot 111 is located between the two powder supply slots 112 along the first direction, and the powder supply slot 112 is located between the building platform 111 and the corresponding overflow powder slot 113 along the first direction. The upper surfaces of the building tank 111, the two powder supply tanks 112 and the two powder overflow tanks 113 are all flush with the horizontal plane perpendicular to the Z axis. The building platform 120 is located in the building tank 111 and rises and falls relative to the building body 110. The building tank 111 and the building platform 120 that descends layer by layer together enclose a building space for forming a three-dimensional printed part. The two powder supply members 130 and the two powder supply tanks 112 are arranged corresponding to each other. The powder supply member 130 is located in the corresponding powder supply tank 112 and rises and falls relative to the building body 110. The powder is contained in the powder containing space enclosed by the powder supply tank 112 and the powder supply member 130.

[0039] like Figure 1 and Figure 2As shown, the printer 200 includes a printer body 210, a powder spreading mechanism 220, a printing mechanism 230, an image acquisition device 240 and a controller (not shown in the figure). The printer body 210 is suitable for the attachment of the building unit 100. When the building unit 100 is attached to the printer body 210, the building slot 111, the two powder supply slots 112 and the two overflow powder slots 113 are arranged along the Y-axis direction, that is, the posture of the building unit 100 is maintained by the printer body 210 as the first direction is the Y-axis direction. The powder spreading mechanism 220 is used to spread the powder in the powder supply slot 112 onto the building platform 120. The powder spreading mechanism 220 is provided with a powder spreading roller, and the powder spreading mechanism 220 reciprocates relative to the printer body 210 along the laying direction, and the laying direction is the Y-axis direction. Therefore, when the building unit 100 is attached to the printer body 210, the laying direction of the powder spreading mechanism 220 is the same as the laying direction of the building slot 111, the two powder supply slots 112 and the two overflow powder slots 113. The lower edge of the powder spreading roller is substantially flush with the upper surfaces of the building groove 111, the two powder supply grooves 112, and the two overflow powder grooves 113. Each time the powder spreading mechanism 220 moves, the powder spreading roller passes over the following components in order: the overflow powder groove 113 on the powder supply side, the powder supply groove 112 on the powder supply side, the building platform 120, the powder supply groove 112 on the powder receiving side, and the overflow powder groove 113 on the powder receiving side. Here, the powder supply side refers to the side where the powder supply groove 112 that the powder spreading mechanism 220 passes first is located, and the powder receiving side refers to the side where the powder supply groove 112 that the powder spreading mechanism 220 passes later is located. The printing mechanism 230 is used to selectively sinter the powder on the building platform 120. The printing mechanism 230 reciprocates along the X-axis direction. Specifically, the printing mechanism 230 includes an injection head 231 and a flux lamp 232. The injection head 231 is used to selectively spray flux onto the powder on the building platform 120. The flux lamp 232 is used to sinter the powder sprayed with flux. Each time the printing mechanism 230 moves, the injection head 231 and the flux lamp 232 pass over the building platform 120. The image acquisition device 240 is fixed to the printer body 210, and is used to acquire images of the upper surface of the powder in the building tank 111 and the two powder supply tanks 112. Therefore, the field of view of the image acquisition device 240 covers the upper surface of the building platform 120 and the two powder supply tanks 112. The controller is connected to the powder spreading mechanism 220, the printing mechanism 230 and the image acquisition device 240 by signal. When the building unit 100 is attached to the printer body 210, the building platform 120 and the two powder supply parts 130 are also connected to the controller by signal. The signal connection here can be an electrical connection or a wireless signal connection. The controller is used to receive the image acquired by the image acquisition device 240 and control the movement of the powder spreading mechanism 220, the printing mechanism 230, the building platform 120 and the two powder supply parts 130 to achieve layer-by-layer printing. Ultimately, the 3D printed part is built layer by layer in the build space.

[0040] See also Figure 3 , Figure 3The specific method of the controller controlling the movement of each component during printing of each layer is shown. Figure 3 As shown, each layer of printing includes a powder supplying step S10, a laying step S20, an image acquiring step S30 and a printing step S40 in sequence.

[0041] The powder supply step S10 includes a process S11 in which the building platform 120 descends according to a first set distance and a powder supply process. The powder supply process also includes a process S12 in which the powder supply member 130 on the powder supply side is lifted according to a lifting distance and a process S13 in which the powder supply member 130 on the powder receiving side descends according to a second set distance. In this embodiment, the controller controls the building platform 120 and the two powder supply members 130 to act simultaneously, that is, the processes S11, S12 and S13 are synchronized and parallel. In other embodiments, the controller can also control the processes S11, S12 and S13 to act successively, and the order of precedence is irrelevant. The first set distance and the second set distance here both refer to distances that have been set manually. That is, when each layer is printed, the distance that the building platform 120 descends is consistent, and the distance that the powder supply member 130 on the powder receiving side descends is also consistent. In other embodiments, the distance that the powder supply member 130 on the powder receiving side descends can vary. The specific calculation method of the lifting distance of the powder supply part 130 on the powder supply side is: when the first layer is printed, the lifting distance is the first distance, and when each layer is printed thereafter, the lifting distance is determined according to the spreading distance obtained when the previous layer was printed. If the spreading distance is less than the threshold, the lifting distance is the first distance, if the spreading distance is greater than the threshold, the lifting distance is the second distance, and if the spreading distance is equal to the threshold, the lifting distance is the first distance or the second distance. Among them, the first distance is greater than the second distance. The spreading distance is the distance that the powder received by the powder supply slot 112 on the powder supply side of the current layer (that is, the powder supply slot 112 on the powder receiving side of the previous layer) spreads along the laying direction of the previous layer when the previous layer was printed after the step S20 is completed. Specifically, the spreading distance is the average value of the distance between the edge line formed by the powder received by the powder supply slot 112 on the powder supply side of the current layer when the previous layer was printed and the slot edge of the powder supply slot 112 closest to the building platform 120 along the laying direction of the previous layer printing (when the edge line is a curve). The specific acquisition method of the spreading distance is that after the image acquired by the image acquisition device 240 in step S30 during the printing of the previous layer is transmitted to the controller, the controller obtains the position of the edge line according to the image processing method, and processes it according to the position of the edge line. The image processing method can be an edge processing algorithm. Further explanation of the first distance and the second distance is required here. The first distance should be set so that the product of the first distance and the horizontal cross-sectional area of ​​the cavity of the powder supply slot 112 is slightly larger than the product of the first set distance and the horizontal cross-sectional area of ​​the cavity of the building slot 111. The second distance should be set so that the product of the second distance and the horizontal cross-sectional area of ​​the cavity of the powder supply slot 112 is slightly smaller than the product of the first set distance and the horizontal cross-sectional area of ​​the cavity of the building slot 111. The threshold here can preferably be set to half of the size of the cavity of the powder supply slot 112 along the Y-axis direction. Of course, the threshold can also be set to one-third of the size of the cavity of the powder supply slot 112 along the Y-axis direction or other values.

[0042] In step S20, the controller controls the powder spreading mechanism 220 to move unidirectionally along the Y-axis direction to spread the powder on the building platform 120, and the powder spreading roller passes over the powder overflow slot 113 on the powder supply side, the powder supply slot 112 on the powder supply side, the building platform 120, the powder supply slot 112 on the powder receiving side, and the powder overflow slot 113 on the powder receiving side during this printing. After step S20, the powder lifted by the powder supply member 130 on the powder supply side is spread on the building platform 120, and the powder overflowing from the building platform 120 overflows into the powder supply slot 112 on the powder receiving side. If the powder supply slot 112 cannot accommodate all the overflowed powder, the overflowed powder will also overflow into the powder overflow slot 113 on the powder receiving side. However, the control method in this embodiment can adjust the first distance, the second distance and the threshold value so that the powder overflowing into the overflow powder slot 113 is as small as possible, or even no powder overflows into the overflow powder slot 113.

[0043] In step S30 , the controller controls the image acquisition device 240 to capture an image and send the image to the controller.

[0044] In step S40 , the controller controls the printing mechanism 230 to move along the X-axis direction to selectively sinter the powder laid on the building platform 120 .

[0045] In this embodiment, by lowering the powder supply member 130 on the powder receiving side, at least most of the powder overflowing from the building platform 120 is received in the powder supply slot 130. Compared with the prior art in which the powder overflowing from the building platform 120 is received in the overflow powder slot 120, at least most of the overflowed powder can be reused for laying on the building platform 120. Therefore, the amount of powder that the building unit 100 needs to carry is less than that of the prior art. It should be noted that the above effect can be achieved by only lowering the powder supply member 130 on the powder receiving side. Therefore, the technical solution for achieving the above technical effect is not limited to the technical solution disclosed in this embodiment, and this implementation is only one of the preferred embodiments.

[0046] In this embodiment, the lifting distance of the powder supply part 130 on the powder supply side is determined by the amount of powder received by the corresponding powder supply groove 112 when the powder laying mechanism 220 lays a layer of powder. Compared with the case where the lifting distance remains unchanged, the amount of powder overflowing from the building platform 120 and falling into the overflow powder groove 113 can be further reduced, thereby further reducing the amount of powder that the building unit 100 needs to carry.

[0047] In this embodiment, under the premise that the powder supply member 130 on the receiving side has a consistent descending distance, the amount of powder received by the powder supply slot 112 when the powder spreading mechanism 220 lays the last layer of powder is characterized by the spreading distance, which can reduce the amount of calculation of the received powder amount compared to other calculation methods. In addition, the lifting distance is limited to the first distance and the second distance, which can optimize the control logic of the lifting distance and avoid the control logic being too complicated.

[0048] In this embodiment, obtaining the spreading distance through the image acquired by the image acquisition device 240 is a preferred implementation method for measuring the spreading distance. This is mainly based on the fact that the received powder can form a clear edge line on the surface of the powder in the powder supply slot 112.

[0049] In this embodiment, by providing the powder overflow slot 113 , in case the powder overflowing from the building platform 120 cannot be completely received by the powder supply slot 112 on the powder receiving side, the excess powder can be received to avoid waste.

[0050] The above specification and description of the embodiments are used to explain the protection scope of the present application, but do not constitute a limitation on the protection scope of the present application.

Claims

1. A powder supply method, which is used to supply powder for three-dimensional printing to a powder spreading mechanism, so that the powder spreading mechanism spreads the powder on a building platform along a laying direction; both sides of the building platform along the laying direction are provided with a powder supply slot and a powder supply member, the powder supply slot is used to accommodate powder, and the powder supply member is located in the corresponding powder supply slot and rises and falls relative to the powder supply slot; wherein, Each time powder is supplied, the powder supply part on the powder supply side supplies powder by lifting, and the powder supply part on the powder receiving side receives the powder overflowed from the building platform by descending; the powder supply side is the side where the powder supply slot is located that the powder spreading mechanism passes through first when laying, and the powder receiving side is the side where the powder supply slot is located that the powder spreading mechanism passes through last when laying.

2. A powder supply method as claimed in claim 1, characterized in that: Each time powder is supplied, the lifting distance of the powder supply member on the powder supply side is determined according to the amount of powder received by the corresponding powder supply slot when the powder spreading mechanism spreads a layer of powder.

3. A powder supply method as claimed in claim 2, characterized in that: Each time powder is supplied, the powder supply member on the receiving side descends the same distance.

4. A powder supply method as claimed in claim 3, characterized in that: The amount of powder received by the powder supply trough when the powder laying mechanism lays the last layer of powder is characterized by the spreading distance of the received powder along the laying direction; when the spreading distance is less than a threshold value, the lifting distance is the first distance; when the spreading distance is greater than the threshold value, the lifting distance is the second distance; when the spreading distance is equal to the threshold value, the lifting distance is the first distance or the second distance; the first distance is greater than the second distance.

5. A powder supply method as claimed in claim 4, characterized in that: The spreading distance is the average value of the distance between the edge line formed by the powder received by the powder supply slot when the powder laying mechanism lays a layer of powder and the slot edge of the powder supply slot close to the building platform along the laying direction.

6. A powder supply method as claimed in claim 5, characterized in that: The spreading distance is obtained by obtaining an image of the upper surface of the powder in the powder supply trough by an image acquisition device after the powder spreading mechanism spreads a layer of powder.

7. A powder supply method as claimed in claim 6, characterized in that: The field of view of the image acquisition device covers the upper surfaces of the building platform and the two powder supply slots.

8. A three-dimensional printing method, which obtains a three-dimensional printed part by printing layer by layer; each layer printing sequentially includes a powder supply step, a laying step and a printing step; the powder supply step includes a building platform descending process and a powder supply process, the laying step is used to lay powder on the building platform, and the printing step is used to selectively sinter the powder laid on the building platform; wherein the method is characterized in that: The powder supply process adopts the powder supply method according to any one of claims 1 to 5.

9. A three-dimensional printing method, which obtains a three-dimensional printed part by printing layer by layer; wherein: Each layer of printing includes a powder supply step, a laying step, an image acquisition step and a printing step in sequence; the powder supply step includes a building platform descending process and a powder supply process, the laying step is used to lay the powder on the building platform, the image acquisition step is used to obtain an image of the upper surface of the powder in the powder supply trough, and the printing step is used to selectively sinter the powder laid on the building platform; wherein, the powder supply process adopts the powder supply method as described in any one of claims 4 to 7, and the diffusion distance is obtained by the image obtained when the previous layer is printed.

10. A three-dimensional printing system, characterized in that: It includes a building unit and a printer; The building unit comprises a building body, a building platform and two powder supply members; the building body is provided with a building slot and powder supply slots located on both sides of the building slot, the building platform is located in the building slot and is lifted relative to the building body, and the powder supply member is located in the corresponding powder supply slot and is lifted relative to the building body; The printer comprises a printer body, a powder spreading mechanism, an image acquisition device and a controller; the printer body is suitable for the attachment of the building unit, the powder spreading mechanism reciprocates relative to the printer body along a laying direction; when the building unit is attached to the printer body, the laying direction is the same as the layout direction of the building slot and the powder supply slot, the image acquisition device is used to acquire images of the upper surfaces of the powders in the building slot and the two powder supply slots, and the controller is signal-connected with the powder spreading mechanism, the image acquisition device, the building platform of the building unit attached to the printer body and the two powder supply parts; The controller receives the image acquired by the image acquisition device and controls the movement of the powder spreading mechanism, the building platform and the two powder supply parts to realize layer-by-layer printing; when printing each layer, the controller first controls the building platform to descend by a first set distance, and controls the powder supply part on the powder supply side to lift by a lifting distance and controls the powder supply part on the powder receiving side to descend by a second set distance; then controls the powder spreading mechanism to sequentially pass through the powder supply slot on the powder supply side and the powder supply slot on the powder receiving side along the laying direction; then controls the image acquisition device to acquire and receive the image; the controller acquires the spreading distance of the powder received in the powder supply slot on the receiving side along the laying direction according to the received image; When the first layer is printed, the lifting distance is the first distance; when each subsequent layer is printed, the lifting distance is determined according to the spreading distance obtained when the previous layer was printed, and when the spreading distance is less than the threshold, the lifting distance is the first distance; when the spreading distance is greater than the threshold, the lifting distance is the second distance; when the spreading distance is equal to the threshold, the lifting distance is the first distance or the second distance; the first distance is greater than the second distance.

11. A three-dimensional printing system as claimed in claim 10, characterized in that: The printer also includes a printing mechanism for printing powder on the building platform, and the controller is also connected to the printing mechanism by signal; when each layer is printed, the controller controls the printing mechanism to print after receiving the image; the building body is also provided with two overflow powder grooves, and the two overflow powder grooves correspond to two powder supply grooves, and the powder supply grooves are located between the building platform and the corresponding overflow powder grooves along the laying direction.

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