Roller type powder spreading device applied to 3D printing

Abstract

The invention relates to the technical field of additive manufacturing, in particular to a roller type powder spreading device applied to 3D printing, the roller type powder spreading device comprises a support, a powder falling mechanism and a spreading mechanism, the powder falling mechanism and the spreading mechanism are installed on the support, the powder falling mechanism comprises a powder bin, a feeding hopper, a stirring assembly and a powder discharging assembly, and the feeding hopper is arranged at the top of the powder bin and communicates with the interior of the powder bin; the stirring assembly and the powder discharging assembly are sequentially arranged in the powder bin from top to bottom, the powder discharging assembly comprises a rotating roller and a plurality of extrusion rods arranged on the rotating roller, the rotating roller is rotationally connected with the powder bin, a plurality of powder discharging holes are formed in the bottom of the powder bin, and when the rotating roller rotates, the extrusion rods extrude powder from the powder discharging holes to the powder bed. By arranging the powder falling mechanism, it can be guaranteed that the amount of powder extruded out of the powder outlet holes is uniform, consistent and quantitative, and the problems of uneven powder laying and powder waste are solved. Powder spreading is carried out in a physical contact and extrusion mode of the extrusion rod and the powder, and the powder spreading device can be compatible with various kinds of powder and is not affected by powder flowability and viscosity.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and particularly to a roller powder spreading device applied to 3D printing. Background Art

[0002] The 3DP forming method is a typical 3D printing technology for powder (particle) materials. This technology was first proposed by the Massachusetts Institute of Technology in the United States in 1989 in a patent with the publication number US5204055A. The specific process is to first evenly spread a layer of powder on a platform, and then the print head scans and sprays a liquid material in a specific area, causing the powder at the spraying site to bond together. At this time, the platform descends a certain layer thickness distance, and the above steps are repeated until all layers of powder spreading and printing work are completed.

[0003] For 3DP type printers, granular materials need to be first added to the powder spreading device, and then the powder spreading device spreads a layer of powder material on the lifting bottom plate. Then, tools such as a squeegee are used to scrape the powder flat. Finally, the nozzle selectively sprays the bonding material onto the already spread powder according to the X-Y cross-sectional shape of the three-dimensional model, causing the powder in the solid area of the prototype cross-section to bond together to form a cross-sectional profile. After one layer is printed, the workbench descends to the height of one cross-section, and then the above steps are repeated until the prototype printing is completed, and the required workpiece is formed by layer-by-layer printing and cumulative forming in this way.

[0004] In the current technology, most of the powder spreading devices used in 3DP type printers are in the form of a powder dropping mechanism + a flattening mechanism. The powder dropping mechanism mostly uses the method of vibrating powder dropping, that is, the powder is dispersed onto the powder bed through vibration. However, this powder dropping method has the problem of uneven vibration, resulting in inconsistent amounts of powder falling onto the powder bed, which will cause problems such as uneven density and powder waste.

[0005] Moreover, the method of vibrating powder dropping has poor compatibility with some powders with low fluidity, and there is a problem that the powder cannot be spread. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a roller powder spreading device applied to 3D printing. By setting a powder dropping mechanism, the present invention can ensure that the amount of powder extruded from the powder outlet is uniform, consistent, and quantitative, solving the problems of uneven powder spreading and powder waste. By spreading powder through the physical contact and extrusion between the extrusion rod and the powder material, various powder materials can be compatible, and it is not affected by the powder fluidity and viscosity.

[0007] The purpose of the present invention is achieved through the following technical solutions: A roller powder spreader used in 3D printing, comprising a bracket and a powder dropping mechanism and a leveling mechanism respectively mounted on the bracket, the powder dropping mechanism comprising a powder bin, a feed hopper, a stirring assembly and a powder outlet assembly, the feed hopper being arranged on the top of the powder bin and communicating with the inside of the powder bin, the stirring assembly and the powder outlet assembly being arranged in sequence from top to bottom inside the powder bin, the stirring assembly being used to evenly transport the powder entering from the feed hopper to various places in the powder bin; The powder outlet assembly comprises a rotating roller, which is rotatably connected to the powder bin. A plurality of powder outlet holes are arranged at the bottom of the powder bin. When the rotating roller rotates, the rotating roller squeezes the powder from the powder outlet holes to the powder bed.

[0008] Furthermore, the stirring assembly includes a stirring shaft and a spiral blade arranged on the stirring shaft, and the stirring shaft is rotatably connected to the powder bin.

[0009] Furthermore, the stirring shaft and the rotating roller are respectively connected to the first driving motor and the second driving motor in driving connection.

[0010] Furthermore, the rotating roller is provided with an air channel along the axial direction, the roller surface of the rotating roller is provided with a plurality of air holes connected with the air channel, one end of the air channel is connected with an air pipe through a joint, and the air pipe is connected to an air source.

[0011] Furthermore, the air pipe is provided with a flow regulating valve and a switch valve.

[0012] Furthermore, an opening is provided at the bottom of the powder bin, and a screen is provided at the opening.

[0013] Furthermore, the screen is an arc-shaped structure, and connecting plates are provided on both sides of the screen along the length direction. The screen is connected to the powder bin through the connecting plates and bolts.

[0014] Furthermore, the powder silo is provided with a material level sensor, and the material level sensor and the feed hopper are respectively located at two ends of the silo.

[0015] Furthermore, the paving mechanism comprises a paving roller, and the paving roller is rotatably arranged on the bracket.

[0016] The beneficial effects of the present invention are: The present invention can ensure that the amount of powder extruded from the powder outlet is uniform, consistent and quantitative by arranging the powder dropping mechanism, thereby solving the problems of uneven powder spreading and powder waste.

[0017] The powder is spread by physical contact and extrusion between the extrusion rod and the powder, which is compatible with various powders and is not affected by the fluidity and viscosity of the powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1A three-dimensional diagram of a roller powder spreader used in 3D printing in an embodiment of the present invention; Figure 2 A top view of a roller powder spreader used in 3D printing; Figure 3 for Figure 2 Middle AA section view; Figure 4 It is a three-dimensional diagram of the rotating roller and the extrusion rod; Figure 5 is a three-dimensional image of the screen; Figure 6 A three-dimensional image of the back side of a roller powder spreader used in 3D printing; In the figure, 1. bracket; 2. powder dropping mechanism; 3. leveling mechanism; 4. powder bin; 5. feed hopper; 6. stirring assembly; 7. powder outlet assembly; 8. rotating roller; 9. leveling roller; 10. powder outlet hole; 11. stirring shaft; 12. spiral blade; 13. airway; 14. air hole; 15. air pipe; 16. flow regulating valve; 17. switch valve; 18. first drive motor; 19. second drive motor; 20. screen; 21. connecting plate; 22. material level sensor. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0020] See also Figures 1-6 , the present invention provides a technical solution: Example

[0021] like Figures 1-6 As shown, a roller powder spreader used in 3D printing includes a bracket 1 and a powder dropping mechanism 2 and a paving mechanism 3 respectively mounted on the bracket 1, wherein the paving mechanism 3 includes a paving roller 9, and the paving roller 9 is rotatably arranged on the bracket 1; the powder dropping mechanism 2 includes a powder bin 4, a feed hopper 5, a stirring assembly 6 and a powder outlet assembly 7, the feed hopper 5 is arranged on the top of the powder bin 4 and communicated with the inside of the powder bin 4, the stirring assembly 6 and the powder outlet assembly 7 are sequentially arranged inside the powder bin 4 from top to bottom, and the stirring assembly 6 is used to uniformly transport the powder entering from the feed hopper 5 to various parts of the powder bin 4; like Figures 3-5As shown, the powder outlet assembly 7 includes a rotating roller 8, which is rotatably connected to the powder bin 4. A plurality of powder outlet holes 10 are provided at the bottom of the powder bin 4. When the rotating roller 8 rotates, the rotating roller 8 squeezes the powder from the powder outlet holes 10 to the powder bed. The output shaft of the second drive motor 19 is coaxially fixed to the rotating roller 8.

[0022] like Figure 3 and Figure 5 As shown, the bottom of the powder bin 4 is provided with an opening, and the opening is provided with an arc-shaped screen 20. The screen holes of the screen 20 constitute the powder outlet 10. The screen 20 is provided with connecting plates 21 on both sides along the length direction, and the connecting plates 21 are connected to the powder bin 4 by bolts.

[0023] like Figure 3 and Figure 6 As shown, the rotating roller 8 is provided with an air passage 13 along the axial direction, and the roller surface of the rotating roller 8 is provided with a plurality of air holes 14 connected to the air passage 13, and one end of the air passage 13 is connected to an air pipe 15 through a joint, and the air pipe 15 is connected to an air source. The air pipe 15 is provided with a flow regulating valve 16 and a switch valve 17.

[0024] The stirring assembly 6 includes a stirring shaft 11 and a spiral blade 12 disposed on the stirring shaft 11, and the stirring shaft 11 is rotatably connected to the powder bin 4. The output shaft of the first drive motor 18 is connected to the stirring shaft 11 through a coupling.

[0025] like Figure 1 As shown, the powder bin 4 is provided with a level sensor 22 for detecting the position of the powder, and the level sensor 22 and the feed hopper 5 are respectively located at both ends of the bin. When the level sensor 22 detects the powder, the stirring shaft 11 stops rotating and the feed hopper 5 stops adding powder.

[0026] Among them, 1. The rotating roller is a stick made of flexible material or covered with flexible materials such as sponge, rubber, cotton cloth, etc., or a hard stick with multiple evenly distributed protrusions on the surface.

[0027] Working principle: When spreading powder, the powder enters the powder bin 4 from the feed hopper 5, and the powder in the powder bin 4 is evenly transported to all parts of the powder bin 4 through the action of the stirring shaft 11 and the spiral blade 12. When the powder is transported, when the material level sensor 22 detects the powder, the stirring shaft 11 stops rotating and the feed hopper 5 stops adding powder.

[0028] When the powder is in place, the second drive motor 19 drives the rotating roller 8 to rotate. During this process, the switch valve 17 is opened and the gas flow is moderated through the flow regulating valve 16. The gas enters the airway 13 through the air pipe 15 and is discharged from the air hole 14. The discharged gas acts on the powder to break up the powder and prevent the powder from agglomerating.

[0029] When the rotating roller 8 rotates, the powder is extruded from the powder outlet hole 10 as the lower side of the rotating roller approaches the powder outlet hole 10. At the same time, since the sizes of the powder holes are the same and the arrangement is uniform, the amount of powder extruded from the powder outlet hole 10 can be ensured to be uniform, consistent and quantitative, solving the problems of uneven powder spreading and powder waste.

[0030] The powder is spread by the physical contact and extrusion of the extrusion rod and the powder material, which can be compatible with various powder materials and is not affected by the fluidity and viscosity of the powder.

[0031] The above are only the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the concept described herein through the above teachings or the techniques or knowledge in related fields. And the changes and modifications made by those skilled in the art that do not depart from the spirit and scope of the present invention should all be within the protection scope of the appended claims of the present invention.

Claims

1. A roller powder spreading device applied to 3D printing, comprising a bracket and a powder dropping mechanism and a leveling mechanism respectively installed on the bracket, characterized in that: The powder dropping mechanism comprises a powder bin, a feed hopper, a stirring assembly and a powder outlet assembly. The feed hopper is arranged on the top of the powder bin and communicates with the inside of the powder bin. The stirring assembly and the powder outlet assembly are arranged inside the powder bin from top to bottom in sequence. The stirring assembly is used to evenly transport the powder entering the feed hopper to various places in the powder bin. The powder outlet assembly comprises a rotating roller, which is rotatably connected to the powder bin, and a plurality of powder outlet holes are provided at the bottom of the powder bin. When the rotating roller rotates, the rotating roller squeezes the powder from the powder outlet holes to the powder bed; The rotating roller is provided with an air channel along the axial direction, and the roller surface of the rotating roller is provided with a plurality of air holes communicated with the air channel. One end of the air channel is connected with an air pipe through a joint, and the air pipe is connected to an air source.

2. The roller powder spreading device applied to 3D printing according to claim 1, wherein: The stirring assembly comprises a stirring shaft and a spiral blade arranged on the stirring shaft, and the stirring shaft is rotatably connected to the powder bin.

3. The roller powder spreading device applied to 3D printing according to claim 2, wherein: The stirring shaft and the rotating roller are respectively connected to the first driving motor and the second driving motor.

4. The roll powder spreading device applied to 3D printing according to claim 1, characterized in that: The air pipe is provided with a flow regulating valve and a switch valve.

5. The roll powder spreading device applied to 3D printing according to claim 2, wherein: The bottom of the powder bin is provided with an opening, and a screen is provided at the opening.

6. The roller powder spreading device applied to 3D printing according to claim 5, characterized in that: The screen is an arc-shaped structure, and connecting plates are provided on both sides of the screen along the length direction. The screen is connected to the powder bin through the connecting plates and bolts.

7. The roll powder spreading device applied to 3D printing according to claim 1, characterized in that: The powder bin is provided with a material level sensor, and the material level sensor and the feed hopper are respectively located at two ends of the bin.

8. The roller powder spreading device applied to 3D printing according to claim 1, characterized in that: The paving mechanism comprises a paving roller, and the paving roller is rotatably arranged on the bracket.

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