Bidirectional rapid powder spreading device, powder 3D printer and bidirectional rapid powder spreading and leveling method

Abstract

The invention discloses a bidirectional rapid powder spreading and leveling device, a powder 3D printer and a bidirectional rapid powder spreading and leveling method. The two-way rapid powder spreading and leveling device comprises two independent powder falling channels, a leveling piece, a stock bin and a distributor. The leveling piece is located between the two powder falling channels and used for leveling powder. The material distributor is arranged at the bottom of the material bin and has at least three positions, when the material distributor is located at the first position, the material bin is communicated with one powder falling channel, when the material distributor is located at the second position, the material bin is communicated with the other powder falling channel, and when the material distributor is located at the third position, the material bin is closed. Bidirectional powder spreading can be achieved under the condition of one stock bin and one leveling piece, and the device is small in size, light in weight and high in integration degree; the mode of leveling while powder falling is adopted, and a compact and flat powder layer can be obtained by moving the leveling piece at a high speed on the premise that the powder laying quality is not affected.

Description

Technical Field

[0001] The invention relates to the field of additive manufacturing, and in particular to a bidirectional rapid powder spreading device, a powder 3D printer and a bidirectional rapid powder spreading and leveling method. Background Art

[0002] Powder bed 3D printing is to selectively sinter metal powder, polymer, ceramic powder and other powder layers according to specific slice patterns by laser beam or radiation heating, and to achieve 3D printing by sintering powder layer by layer. Due to its advantages of high precision and good surface quality, it is widely used in the molding and processing of metal, polymer materials and even ceramic parts.

[0003] The powder spreading speed in powder bed 3D printing is a key factor affecting the printing speed. At present, the commonly used powder spreading methods are upper powder spreading method and lower powder spreading method. Regardless of upper powder spreading or lower powder spreading, the powder required for a layer of powder is usually placed on one side of the printing chamber at one time, and then the powder is pushed as a whole. Since the powder accumulates on the powder spreading shear surface and the powder has poor fluidity, leveling parts such as leveling rollers or scrapers need to spread the powder at a slower speed to obtain a dense and flat powder layer, otherwise it will affect the printing quality. Therefore, the commonly used powder spreading method will result in a slower powder spreading speed, resulting in lower overall printing efficiency and longer printing time. How to increase the powder spreading speed is a problem to be improved. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a bidirectional rapid powder spreading device, a bidirectional rapid powder spreading and leveling method and a powder 3D printer, which can spread powder quickly without affecting the powder spreading quality and improve the overall printing efficiency.

[0005] The present invention adopts the following technical solutions:

[0006] A bidirectional rapid powder spreading and leveling device comprises two independent powder falling channels, a leveling piece, a silo and a distributor, wherein the leveling piece is located between the two powder falling channels and is used to level the powder; the distributor is arranged at the bottom of the silo, and the distributor has at least three positions. In the first position, the silo is connected to one of the powder falling channels, in the second position, the silo is connected to the other powder falling channel, and in the third position, the silo is closed.

[0007] Preferably, the bidirectional rapid powder spreading device further comprises a pre-pressing inclined surface arranged between the powder falling channel and the leveling member, the pre-pressing inclined surface is used to pre-press the powder falling through the powder falling channel, and the pre-pressing inclined surface cooperates with the powder falling channel to form a flared powder outlet. By pre-pressing the powder layer with the pre-pressing inclined surface, the resistance of the leveling member behind can be reduced, thereby improving the leveling efficiency.

[0008] Preferably, the leveling member is a leveling roller, which can rotate in both directions; the pre-pressing slope is set at an angle of 30-60° with the vertical direction. The leveling roller can select a suitable rotation direction according to different powder drop channel connection conditions, so only one leveling roller is needed to achieve the bidirectional leveling function.

[0009] Preferably, the bidirectional rapid powder spreading device comprises a leveling roller bracket for fixing the leveling roller, and the pre-pressing inclined surfaces are respectively arranged on two opposite sides of the leveling roller bracket.

[0010] Preferably, the bidirectional rapid powder spreading device further comprises a negative pressure channel arranged between the pre-pressing inclined surface and the leveling roller, and the negative pressure channel is used to remove excess powder by negative pressure. Negative pressure quickly removes excess powder, thereby improving the powder spreading speed and powder spreading quality.

[0011] Preferably, an agitator is provided in the silo, and a heating element is provided on the silo wall.

[0012] Preferably, the bidirectional rapid powder spreading device has a first powder dropping channel and a second powder dropping channel, the leveling piece is located between the first powder dropping channel and the second powder dropping channel, the first pre-pressure slope is arranged between the first powder dropping channel and the leveling piece, the second pre-pressure slope is arranged between the second powder dropping channel and the leveling piece, the first negative pressure channel is arranged between the first pre-pressure slope and the leveling piece, and the second negative pressure channel is arranged between the second pre-pressure slope and the leveling piece.

[0013] The present invention also provides a powder 3D printer with bidirectional rapid powder spreading and leveling. The powder 3D printer includes a printing chamber and the bidirectional rapid powder spreading device. A printing platform is provided at the bottom of the printing chamber. The printing platform can be raised and lowered relative to the bidirectional rapid powder spreading device. The bidirectional rapid powder spreading device can move back and forth in both directions above the printing platform to spread powder and level it.

[0014] Preferably, powder dropping plates are provided on both sides of the printing bin, and the powder 3D printer further comprises a powder bin, which is used to provide powder to the silo.

[0015] The present invention also provides a bidirectional rapid powder spreading and leveling method, which uses a powder 3D printer for bidirectional rapid powder spreading and leveling, comprising the following steps:

[0016] When the bidirectional rapid powder spreading device moves from the first side of the printing platform to the second side, the distributor moves to the first position so that the first powder dropping channel located in front of the moving direction of the leveling member is opened, and the first pre-pressing inclined surface pre-presses the powder, and then the leveling member rotates against the powder laying direction to level the pre-pressed powder, and the excess powder is removed through the first negative pressure channel, and the laying of a layer of powder is completed, and the distributor moves to the third position to close the silo;

[0017] When the layer of powder is sintered / melted, the bidirectional rapid powder spreading device moves from the second side of the printing platform back to the first side, the distributor moves to the second position so that the second powder dropping channel located in front of the moving direction of the leveling member is opened, the second pre-pressing inclined surface pre-presses the powder, and then the leveling member rotates against the powder laying direction to level the pre-pressed powder, and the excess powder is removed through the second negative pressure channel to complete the laying of another layer of powder, and the distributor moves to the third position to close the silo;

[0018] Repeat the above steps to lay down the powder layer by layer until the entire 3D object is printed.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] Two independent powder dropping channels are set up, and the different powder dropping channels are connected by controlling the distributor. Under the conditions of one silo and one leveling piece, two-way powder spreading can be achieved. The device has a small size and high integration. The method of dropping powder and leveling at the same time is adopted. Compared with placing the powder on one side of the printing bin at one time and then pushing the powder as a whole to spread the powder, the powder spreading method of the present application can move the leveling piece at a faster speed to obtain a dense and flat powder layer without affecting the powder spreading quality. A pre-pressing slope is set, and the powder layer is first pre-pressed by the pre-pressing slope and then leveled by the leveling piece, which reduces the resistance of the leveling piece to leveling and improves the leveling efficiency. Compared with not setting the pre-pressing function, the powder spreading time can be shortened by about 20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the two-way rapid powder spreading device and the powder bin;

[0022] Figure 2 A schematic diagram of a process of a bidirectional rapid powder spreading device moving from a first side to a second side of a printing platform;

[0023] Figure 3 The figure is a schematic diagram of the process of the bidirectional rapid powder spreading device moving from the second side to the first side of the printing platform.

[0024] In the figure, 100-powder 3D printer, 1-bidirectional fast powder spreading device, 11a-first powder dropping channel, 11b-second powder dropping channel, 12a-first pre-pressing slope, 12b-second pre-pressing slope, 13-leveling roller, 14-material bin, 15-distributor, 16-leveling roller bracket, 17a-first negative pressure channel, 17b-second negative pressure channel, 18-cover plate, 191-agitator, 192-heating element, 193-powder outlet, 2-printing bin, 21-printing platform, 3-powder, 31-a powder layer, 32-another powder layer, 33-excess powder, 4-powder dropping plate, 5-powder bin, 6-local 3D object. DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the technical solution of the present invention, a detailed description is given below in conjunction with the accompanying drawings and specific embodiments.

[0026] See also Figure 1-Figure 3 , which is an embodiment of the powder 3D printer 100 for bidirectional fast powder spreading and leveling of the present invention. The powder 3D printer 100 for bidirectional fast powder spreading and leveling comprises a bidirectional fast powder spreading device 1 and a printing chamber 2. The bidirectional fast powder spreading device 1 is as shown in FIG. Figure 1 As shown, it includes two independent powder falling channels 11a, 11b, a leveling member 13, a silo 14 and a distributor 15. The leveling member 13 is located between the two powder falling channels 11a, 11b and is used to level the powder 3. The distributor 15 is arranged at the bottom of the silo 14 and has at least three positions. Figure 2 In the first position shown in FIG. 1 , the hopper 14 is connected to one of the powder dropping channels 11a. Figure 3 In the second position shown in FIG. 1 , the hopper 14 is connected to another powder dropping channel 15. Figure 1 In the third position shown, the silo 14 is closed.

[0027] The distributor 15 can be driven to rotate by other driving mechanisms such as a motor, and the three positions can be limited by the positioning structure. The specific implementation will not be described in detail here, and the R&D personnel can design it by themselves in combination with the existing technology. The rotation of the distributor 15 can realize the connection between the powder falling channels 11a, 11b and the silo 14. The powder falling channels 11a, 11b are arranged below the silo 14, and the powder 3 can enter the powder falling channels 11a, 11b from the silo 14 by gravity and fall into the position where the powder layer needs to be laid. For the convenience of distinction, the powder falling channels are named as the first powder falling channel 11a and the second powder falling channel 11b.

[0028] The leveling member 13 is located between the first powder dropping channel and the second powder dropping channel. In this embodiment, the leveling member is a leveling roller 13, but it can also be a scraper or other device that can perform the leveling function. The leveling roller 13 can rotate in both directions, and the appropriate rotation direction is selected according to the different powder dropping channel connection conditions, so only one leveling roller is needed to achieve the bidirectional leveling function.

[0029] The bidirectional rapid powder spreading device 1 also includes pre-pressing inclined surfaces 12a, 12b arranged between the powder falling channel and the flattening member, and the pre-pressing inclined surfaces 12a, 12b are used to pre-press the powder 3 falling through the powder falling channels 11a, 11b, and the pre-pressing inclined surfaces 12a, 12b cooperate with the powder falling channels 11a, 11b to form a flared powder outlet 193, which is convenient for powder falling. For the convenience of distinction, the first pre-pressing inclined surface 12a is named between the first powder falling channel 11a and the flattening roller 13, and the second pre-pressing inclined surface 12b is named between the second powder falling channel 11b and the flattening roller 13. Preferably, the pre-pressing inclined surfaces 12a, 12b are set at an angle of 30-60° with the vertical direction. An angle that is too large or too small is not conducive to the pre-pressing of the powder. More preferably, the pre-pressing inclined surfaces 12a, 12b are set at an angle of 45° with the vertical direction.

[0030] The bidirectional fast powder spreading device 1 includes a leveling roller bracket 16 for fixing the leveling roller, and the pre-pressing inclined surfaces 12a, 12b are respectively arranged on two opposite sides of the leveling roller bracket 16. The bidirectional fast powder spreading device 1 also includes negative pressure channels 17a, 17b arranged between the pre-pressing inclined surface and the leveling roller, and the negative pressure channels 17a, 17b are used to remove excess powder 33 by negative pressure. The first negative pressure channel 17a is arranged between the first pre-pressing inclined surface 12a and the leveling roller 13, and the second negative pressure channel 17b is arranged between the second pre-pressing inclined surface 12b and the leveling roller 13. A cover plate 18 is also arranged above the leveling roller 13, and the negative pressure channels 17a, 17b are isolated by the cover plate 18.

[0031] Since the powder has poor fluidity and is easy to agglomerate, a stirrer 191 is also provided in the silo 14. The sintering of the powder requires a relatively high temperature, so a heating element 192 is provided on the silo wall of the silo 14 to preheat the powder.

[0032] like Figure 2-Figure 3 As shown, a printing platform 21 is provided at the bottom of the printing chamber 2, and the printing platform 21 can be raised and lowered relative to the bidirectional rapid powder spreading device 1. The relative lifting referred to here can be that the printing platform 21 is raised and lowered while the bidirectional rapid powder spreading device 1 remains stationary in the vertical direction, or the bidirectional rapid powder spreading device 1 is raised and lowered while the printing platform 21 remains stationary. The bidirectional rapid powder spreading device 1 can move back and forth in both directions from above the printing platform 21 to spread powder and level it.

[0033] Powder dropping plates 4 are provided on both sides of the printing chamber 2. The bidirectional rapid powder spreading device 1 starts to drop powder quantitatively from the end of the powder dropping plate 4, and completes the laying of the powder layer by pre-pressing and leveling while moving, so as to achieve powder dropping and leveling while moving. Compared with placing the powder on one side of the printing chamber at one time and then pushing the powder as a whole, the powder spreading method of this embodiment can move the leveling roller 13 at a faster speed (100-600mm / s) to obtain a dense and flat powder layer without affecting the quality of the powder spreading; in addition, the powder layer is pre-pressed by the pre-pressing inclined surfaces 12a and 12b, which reduces the resistance of the leveling roller 13 to leveling, improves the leveling efficiency, and can shorten the powder spreading time by about 20% compared with not setting the pre-pressing function. Compared with the prior art, the present invention can achieve a forming speed of one layer per 6 seconds, or even higher (taking the thickness of one layer of powder as 0.1mm and the forming area as 300mm*500mm as an example).

[0034] The powder 3D printer 100 also includes a powder bin 5, which is used to provide powder to the silo 14 in a quantitative manner, such as providing 2 layers or more of powder according to the size of the silo, and when the powder in the silo 14 is used up, it is moved to the bottom of the powder bin 5 to add powder again.

[0035] This embodiment also provides a two-way rapid powder spreading and leveling method, comprising the following steps:

[0036] like Figure 2 As shown, when the bidirectional rapid powder spreading device 1 moves from the first side to the second side of the printing platform 21, the distributor 15 moves to the first position so that the first powder dropping channel 11a located in front of the moving direction of the leveling roller 13 is opened, and the powder 3 falls onto the powder dropping plate 4 and the printing platform 21, and the first pre-pressing slope 12a pre-presses the powder 3, and then the leveling roller 13 rotates against the powder laying direction (counterclockwise in the figure) to level the pre-pressed powder 3, and the excess powder 33 is removed through the first negative pressure channel 17a, completing the laying of a powder layer 31; the distributor 15 moves to the third position to close the silo 14;

[0037] When the powder layer 31 is sintered / melted, Figure 3 As shown, the bidirectional rapid powder spreading device 1 moves from the second side of the printing platform 21 back to the first side, the distributor 15 moves to the second position so that the second powder dropping channel 11b located in front of the moving direction of the leveling roller 13 is opened, and the powder 3 falls onto the powder layer 31. The second pre-pressing slope 12a pre-presses the powder 3, and then the leveling roller 13 rotates against the powder laying direction (because the powder laying direction is changed, the moving direction of the leveling roller is clockwise in the figure) to level the pre-pressed powder 3, and the excess powder 33 is removed through the second negative pressure channel 17b, completing the laying of another layer of powder layer 32, and the distributor 15 moves to the third position to close the silo 1;

[0038] Repeat the above steps to lay the powder layer by layer until the entire 3D object is printed ( Figure 2 , Figure 3 The reference numeral 6 represents a local 3D object).

[0039] The above are only preferred embodiments of the present invention. The protection scope of the present invention shall be based on the scope defined by the claims. Several improvements and modifications made by those skilled in the art without departing from the spirit and scope of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A two-way rapid powder spreading and leveling device, characterized in that: It includes two independent powder falling channels, a leveling piece, a silo and a distributor. The leveling piece is located between the two powder falling channels and is used to level the powder. The distributor is arranged at the bottom of the silo. The distributor has at least three positions. In the first position, the silo is connected to one of the powder falling channels. In the second position, the silo is connected to the other powder falling channel. In the third position, the silo is closed.

2. The bidirectional rapid powder spreading device according to claim 1, characterized in that: The bidirectional rapid powder spreading device also includes a pre-compression slope arranged between the powder falling channel and the flattening member, the pre-compression slope is used to pre-compress the powder falling through the powder falling channel, and the pre-compression slope cooperates with the powder falling channel to form a flared powder outlet.

3. The bidirectional rapid powder spreading device according to claim 2, characterized in that: The flattening member is a flattening roller, and the flattening roller can rotate in both directions; the pre-pressing inclined surface is arranged at an angle of 30-60° with the vertical direction.

4. The bidirectional rapid powder spreading device according to claim 3, characterized in that: The bidirectional rapid powder spreading device comprises a leveling roller bracket for fixing the leveling roller, and the pre-pressing inclined surfaces are respectively arranged on two opposite side surfaces of the leveling roller bracket.

5. The bidirectional rapid powder spreading device according to claim 3, characterized in that: The bidirectional rapid powder spreading device also includes a negative pressure channel arranged between the pre-pressing inclined surface and the leveling roller, and the negative pressure channel is used to remove excess powder through negative pressure.

6. The bidirectional rapid powder spreading device according to claim 1, characterized in that: A stirrer is arranged in the silo, and a heating element is arranged on the silo wall.

7. The bidirectional rapid powder spreading device according to claim 5, characterized in that: The bidirectional rapid powder spreading device has a first powder dropping channel and a second powder dropping channel, the flattening piece is located between the first powder dropping channel and the second powder dropping channel, the first pre-pressing slope is arranged between the first powder dropping channel and the flattening piece, the second pre-pressing slope is arranged between the second powder dropping channel and the flattening piece, the first negative pressure channel is arranged between the first pre-pressing slope and the flattening piece, and the second negative pressure channel is arranged between the second pre-pressing slope and the flattening piece.

8. A powder 3D printer with bidirectional rapid powder spreading and leveling, characterized in that: The powder 3D printer comprises a printing chamber and a bidirectional rapid powder spreading device as described in any one of claims 1 to 7, wherein a printing platform is provided at the bottom of the printing chamber, the printing platform can be raised and lowered relative to the bidirectional rapid powder spreading device, and the bidirectional rapid powder spreading device can move back and forth in both directions from above the printing platform to spread powder and level it.

9. The powder 3D printer with bidirectional rapid powder spreading and leveling as claimed in claim 8, characterized in that: Powder dropping plates are provided on both sides of the printing bin, and the powder 3D printer further comprises a powder bin, which is used to provide powder for the silo.

10. A two-way rapid powder spreading and leveling method, using the powder 3D printer for two-way rapid powder spreading and leveling as claimed in claim 8, characterized in that The following steps are involved: When the bidirectional rapid powder spreading device moves from the first side of the printing platform to the second side, the distributor moves to the first position so that the first powder dropping channel located in front of the moving direction of the leveling member is opened, and the first pre-pressing inclined surface pre-presses the powder, and then the leveling member rotates against the powder laying direction to level the pre-pressed powder, and the excess powder is removed through the first negative pressure channel, and the laying of a layer of powder is completed, and the distributor moves to the third position to close the silo; When the layer of powder is sintered / melted, the bidirectional rapid powder spreading device moves from the second side of the printing platform back to the first side, the distributor moves to the second position so that the second powder dropping channel located in front of the moving direction of the leveling member is opened, the second pre-pressing inclined surface pre-presses the powder, and then the leveling member rotates against the powder laying direction to level the pre-pressed powder, and the excess powder is removed through the second negative pressure channel to complete the laying of another layer of powder, and the distributor moves to the third position to close the silo; Repeat the above steps to lay down the powder layer by layer until the entire 3D object is printed.

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