A powder-adding SLM powder spreading device

Abstract

The present invention discloses a powder-adding SLM powder spreading device, which belongs to the field of additive manufacturing technology; it includes a gas protection box and a workbench located inside the gas protection box, a powder storage cylinder is provided on the top of the gas protection box, and a powder spreading assembly is provided inside the gas protection box; the powder spreading assembly includes a powder placing box movable along the length direction of the workbench and an openable and closable powder discharging unit, a receiving hopper is provided on the upper part of the powder placing box, the powder discharging unit is arranged at the lower part of the powder placing box and is connected with the powder placing box, and the powder discharging unit can release powder to the workbench; the outer wall of the powder storage cylinder is fixedly connected to the gas protection box, and a transition bin and a powder storage bin are provided inside the powder storage cylinder from top to bottom, and a first interface for vacuuming is provided on the transition bin, and the top of the powder storage bin is connected with the transition bin through a valve, and a sealing door that can be opened and closed is provided at the bottom of the powder storage bin, and the powder storage bin can convey powder to the receiving hopper through the sealing door. The present invention can continuously and efficiently supply powder.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a powder-adding SLM powder spreading device. Background Art

[0002] Additive manufacturing (or 3D printing) technology forms a three-dimensional entity through the orderly layer-by-layer accumulation of materials. It can realize the integration of complex parts and lightweight forming. It has the advantages of high material utilization and strong flexibility in forming process. It is gradually entering the application in the fields of aviation, aerospace, precision molds, nuclear energy, and medical treatment, and has broad prospects. At present, the most common form of metal additive manufacturing is powder bed melting. The metal melting heat sources used in this process include lasers and electron beams. Taking the selective laser melting technology (SLM) technology as an example, it uses laser as the energy source, and melts the powder particles together point by point on the metal powder bed powder layer, and processes layer by layer to produce the desired product.

[0003] When performing rapid prototyping of titanium and titanium alloys, due to the high requirements for the gas environment (oxygen and water content below 1ppm), it often takes a considerable amount of time to meet this requirement. When the gas environment meets the requirements, during the rapid prototyping process, if there is not enough powder, printing cannot be completed. If the gas protection box is opened to add powder, the gas environment will be destroyed and it will take a long time to meet the environmental requirements. Summary of the invention

[0004] In view of this, it is necessary to provide a powder-adding SLM powder spreading device to solve the problem of poor powder supply in the existing powder spreading device.

[0005] The present invention provides a powder-adding SLM powder spreading device, comprising a gas protection box and a workbench located inside the gas protection box, a powder storage cylinder is provided on the top of the gas protection box, and a powder spreading assembly is provided inside the gas protection box;

[0006] The powder spreading assembly includes a powder placing box movable along the length direction of the workbench and a powder discharging unit that can be opened and closed, a receiving hopper is provided at the upper part of the powder placing box, the powder discharging unit is arranged at the lower part of the powder placing box and is connected to the powder placing box, and the powder placing box can release powder to the workbench through the powder discharging unit;

[0007] The outer wall of the powder storage cylinder is fixedly connected to the gas protection box, and the interior of the powder storage cylinder is provided with a transition bin and a powder storage bin from top to bottom. The transition bin is provided with a first interface for vacuuming, and the top of the powder storage bin is connected to the transition bin through a valve. The bottom of the powder storage bin is provided with an openable and closable sealing door, and the powder storage bin can transport powder to the receiving hopper through the sealing door.

[0008] Furthermore, a sealing cover for connecting the outside world and the transition bin is provided on the top of the powder storage cylinder, and the sealing cover can block the gas flow between the transition bin and the outside world.

[0009] Furthermore, the transition chamber is provided with a second interface for accessing the inert gas.

[0010] Furthermore, the powder spreading assembly also includes a linear drive unit, which includes a scraper and a screw. The two screws are rotatably connected to the inner walls on both sides of the gas protection box through supports, and the two sides of the scraper are respectively screwed to the screws, and the screw can drive the scraper to move linearly.

[0011] Furthermore, the bottom of the scraper is in contact with the workbench, the powder box is located between the two screws, the side of the powder box is fixedly connected to the side of the scraper, and the bottom of the powder box is spaced apart from the workbench.

[0012] Furthermore, a forming cylinder is provided in the gas protection box, the forming cylinder is embedded in the workbench, the forming cylinder is located on the moving path of the powder setting box, and a retractable piston is provided in the forming cylinder.

[0013] Furthermore, a recovery cylinder is provided between the forming cylinder and the inner wall of the gas protection box. The recovery cylinder is located on a side of the forming cylinder away from the powder placing box, and the recovery cylinder is embedded in the workbench.

[0014] Furthermore, the powder outlet unit includes a flap, an elastic member and a guide wheel. An opening is provided at the bottom of the powder box. The middle part of the flap is hinged to one side of the opening. The end of the flap close to the scraper is connected to the powder box through an elastic member so that the flap can automatically close the opening.

[0015] Furthermore, the guide wheels are arranged on both sides of the other end of the flap, and bosses cooperating with the guide wheels are arranged on both sides of the inner wall of the gas protection box, and protrusions for moving the flap are arranged on the bosses.

[0016] Furthermore, a diverter plate is provided inside the powder placing box, and a plurality of the diverter plates are arranged around the receiving hopper, and the diverter plates can guide the powder to be evenly laid on the flap.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The powder-addable SLM powder spreading device of the present invention can directly process the gas in the transition bin by setting up a transition bin, ensuring that the powder storage bin always stores an appropriate amount of powder and that the gas in the powder storage bin meets the requirements, thereby saving working time and improving production efficiency.

[0019] (2) A powder-adding SLM powder spreading device of the present invention is provided with a powder spreading component in a gas protection box, the powder spreading component includes a powder placing box that can move along a workbench and a powder discharging unit that can be opened and closed, the powder placing box can move on the workbench along a set track to spread powder on the workbench. The powder discharging unit can automatically release the powder in the powder placing box, with a high degree of automation and good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 A schematic diagram of the overall structure of the present invention

[0022] Figure 2 It is a structural schematic diagram of the central powder box of the present invention;

[0023] Figure 3 yes Figure 1 A schematic diagram of the structure of the local enlargement of the A;

[0024] Figure 4 yes Figure 2 A schematic diagram of the structure of the local enlargement at B;

[0025] In the figure, a gas protection box 100, a boss 110, a protrusion 111, a workbench 200, a powder storage cylinder 300, a transition bin 310, a first interface 311, a second interface 312, a powder storage bin 320, a sealing door 321, a sealing cover 330, a powder spreading assembly 400, a powder placing box 410, a material receiving hopper 411, an opening 412, a diverter plate 413, a powder outlet unit 420, a flap 421, an elastic member 422, a guide wheel 423, a linear drive unit 430, a scraper 431, a screw 432, a forming cylinder 500, a piston 510, and a recovery cylinder 600. DETAILED DESCRIPTION

[0026] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0027] See also Figures 1 to 4In this embodiment, a powder-adding SLM powder spreading device includes a gas protection box 100 and a workbench 200 located inside the gas protection box 100. The powder spreading process is carried out on the workbench 200, and a suitable gas environment is maintained inside the gas protection box 100. A powder storage cylinder 300 is provided on the top of the gas protection box 100, and the powder storage cylinder 300 can transport powder into the gas protection box 100 in time without disturbing the gas environment. A powder spreading component 400 is provided inside the gas protection box 100, and the powder spreading component 400 can evenly spread powder on the workbench 200.

[0028] The powder spreading assembly 400 includes a powder placing box 410 that can move along the length direction of the workbench 200 and a powder discharging unit 420 that can be opened and closed. The powder placing box 410 can move on the workbench 200 along the length direction of the workbench 200 to spread powder on the workbench 200. A receiving hopper 411 is provided on the upper part of the powder placing box 410, and powder from the outside is input into the powder placing box 410 from the receiving hopper 411. The powder discharging unit 420 is arranged at the lower part of the powder placing box 410 and is connected to the powder placing box 410. The powder discharging unit 420 can be opened and closed automatically. When the powder discharging unit 420 is opened, the powder discharging unit 420 can release the powder stored inside onto the workbench 200. When the powder discharging unit 420 is closed, the powder placing box 410 can temporarily store powder inside.

[0029] The outer wall of the powder storage cylinder 300 is fixedly connected to the gas protection box 100. The interior of the powder storage cylinder 300 is provided with a transition bin 310 and a powder storage bin 320 from top to bottom. The transition bin 310 is provided with a first interface 311 for vacuuming. The first interface 311 can be connected to a vacuum pump by means of a pipeline to extract the air in the transition bin 310 and reduce the oxygen content. The top of the powder storage bin 320 is connected to the transition bin 310 through a valve. The valve is an electrically controlled tank bottom valve. The powder in the transition bin 310 can enter the powder storage bin 320 under the action of gravity. The bottom of the powder storage bin 320 is provided with an openable and closable sealing door 321. The sealing door 321 is a common valve. The powder storage bin 320 can convey powder to the receiving hopper 411 through the sealing door 321. By setting up the transition bin 310, the gas in the transition bin 310 can be directly processed to ensure that the powder storage bin 320 always stores an appropriate amount of powder and the gas in the powder storage bin 320 meets the requirements, which saves working time and improves production efficiency.

[0030] See also Figure 1A sealing cover 330 for connecting the outside world and the transition bin 310 is provided on the top of the powder storage cylinder 300. Powder can be added from the outside world to the transition bin 310 through the sealing cover 330. The sealing cover 330 is connected to the powder storage cylinder 300 through a thread. When the gas in the transition bin 310 needs to be processed, the airtightness inside the transition bin 310 can be ensured by sealing the sealing cover 330, thereby blocking the gas flow between the transition bin 310 and the outside world and reducing the time required for gas conversion.

[0031] As a further embodiment, a second interface 312 for connecting inert gas is provided on the transition chamber 310. The second interface 312 is connected to the inert gas supply tank through a pipeline. The inert gas can be supplied to the transition chamber 310 via the second interface 312 to assist the transformation of the gas environment in the transition chamber 310.

[0032] See also Figure 1 and Figure 3 The powder spreading assembly 400 further includes a linear drive unit 430, which includes a scraper 431 and a screw 432. The two screws 432 are rotatably connected to the inner walls of the gas protection box 100 on both sides through a support, and the two sides of the scraper 431 are respectively screwed to the screw 432. In the specific implementation process, a servo motor is provided at the end of the screw 432, the housing of the servo motor is fixedly connected to the inner wall of the gas protection box 100, and the output shaft of the servo motor is connected to the screw 432. The servo motor can drive the screw 432 to rotate, thereby driving the scraper 431 to move along the length direction of the screw 432 as a whole to perform the powder spreading operation.

[0033] As a further embodiment, the bottom of the scraper 431 abuts against the workbench 200, the powder box 410 is located between the two screws 432, the side of the powder box 410 is fixedly connected to the side of the scraper 431, and the bottom of the powder box 410 is spaced apart from the workbench 200. The scraper 431 can drive the powder box 410 to move synchronously, and after the powder box 410 releases powder onto the workbench 200, the scraper 431 abutting against the workbench 200 can flatten the released powder.

[0034] See also Figure 1 , a forming cylinder 500 is provided in the gas protection box 100, the forming cylinder 500 is embedded in the workbench 200, the forming cylinder 500 is located on the moving path of the powder box 410, and a retractable piston 510 is provided in the forming cylinder 500. In the specific implementation process, the piston 510 is lowered to the set slice thickness, so that there is a height difference between the top surface of the piston 510 and the plane of the workbench 200, and the depth of the height difference is consistent with the set slice thickness. When the scraper 431 passes through the forming cylinder 500, the powder is spread on the piston 510 to form a powder slice of the set thickness.

[0035] A recovery cylinder 600 is provided between the forming cylinder 500 and the inner wall of the gas protection box 100. The recovery cylinder 600 is located on the side of the forming cylinder 500 away from the powder placing box 410, and the recovery cylinder 600 is embedded in the workbench 200. Excess powder will be pushed into the recovery cylinder 600 by the scraper 431 and stored for reuse. The recovery cylinder 600 prevents the powder from accumulating in the gas protection box 100 and hindering the powder spreading process.

[0036] It should be noted that the linear drive unit 430 can also be implemented in a variety of ways, such as using a hydraulic rod, a cylinder or an electric push rod, and the scraper 431 is connected to the inner wall of the gas protection box 100 via the above components, which can push the scraper 431 to move linearly as a whole to achieve the purpose of flattening the powder. In addition, a gear rack transmission mechanism can also be used to connect the scraper 431 and the gas protection box 100 to drive the scraper 431 to move linearly to complete the corresponding function.

[0037] See also Figure 3 and Figure 4 The powder discharge unit 420 includes a flap 421, an elastic member 422 and a guide wheel 423. An opening 412 is provided at the bottom of the powder box 410. The middle part of the flap 421 is hinged to one side of the opening 412. The end of the flap 421 close to the scraper 431 is connected to the powder box 410 through the elastic member 422. The elastic member 422 is specifically a spring. The elastic member 422 always gives the flap 421 a force close to the opening 412, so that the flap 421 can automatically close the opening 412 to prevent the release of powder inside the powder box 410. In the specific implementation process, the guide wheel 423 is arranged on both sides of the other end of the flap 421, and the other end of the flap 421 extends a guide shaft to both sides, the guide shaft protrudes from the flap 421 and is spaced from the flap 421, and the guide wheel 423 is installed on the guide shaft, and the inner wall of the gas protection box 100 is provided with a boss 110 that cooperates with the guide wheel 423, and the wheel surface of the guide wheel 423 abuts against the upper surface of the boss 110, and the boss 110 is provided with a protrusion 111 for moving the flap 421. When the guide wheel 423 passes the protrusion 111, the guide wheel 423 is moved up, and correspondingly, the other side of the flap 421 drops, and the flap 421 overcomes the elastic force of the elastic member 422, opens the opening 412, and the powder in the powder box 410 is released. After the guide wheel 423 passes the protrusion 111, the flap 421 is restored, and the opening 412 is closed again, waiting for the input of powder.

[0038] It should be noted that the powder discharging unit 420 may be an electromagnetic valve, which is connected to the powder box 410 and the receiving hopper 411, and the opening and closing of the electromagnetic valve can be controlled by a switch to control the release of the powder. In addition, the powder discharging unit 420 may also be a cover plate, which is arranged parallel to the opening 412 of the powder box 410, one end of the cover plate is fixedly connected to the inner wall of the gas protection box 100, and the upper end of the cover plate can abut against the opening 412. When the powder box 410 moves to one side relative to the powder storage cylinder 300, the cover plate can be gradually inserted under the opening 412 to close the opening 412.

[0039] See also Figure 2 The interior of the powder box 410 is provided with a diverter plate 413 arranged around the receiving hopper 411. Multiple diverter plates 413 are arranged around the receiving hopper 411. The powder input into the powder box 410 from the receiving hopper 411 can be evenly distributed in the length direction of the flap 421 through the guidance of the diverter plate 413, so as to avoid powder clumping and accumulation, resulting in uneven distribution of the laid slice layers, which seriously affects the slice quality.

[0040] Workflow: First, add powder into the transition bin 310 through the sealing cover 330. After changing the gas environment in the transition bin 310, input the powder in the transition bin 310 into the powder storage bin 320, and quantitatively add powder into the powder setting box 410. When spreading the powder, a proper amount of powder is added into the powder setting box 410, and then the powder discharging unit 420 is opened to release the powder onto the workbench 200. Under the action of the linear drive unit 430, the scraper 431 spreads the powder onto the piston 510 to form corresponding powder slices.

[0041] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present invention should be covered by the present invention.

Claims

1. A powder-adding SLM powder spreading device, comprising a gas protection box and a workbench located inside the gas protection box, It is characterized in that A powder storage cylinder is provided on the top of the gas protection box, and a powder spreading assembly is provided inside the gas protection box; The powder spreading assembly includes a powder placing box movable along the length direction of the workbench and a powder discharging unit that can be opened and closed, a receiving hopper is provided at the upper part of the powder placing box, the powder discharging unit is arranged at the lower part of the powder placing box and is connected to the powder placing box, and the powder placing box can release powder to the workbench through the powder discharging unit; The outer wall of the powder storage cylinder is fixedly connected to the gas protection box, and a transition bin and a powder storage bin are arranged inside the powder storage cylinder from top to bottom. The transition bin is provided with a first interface for vacuuming, and the top of the powder storage bin is connected to the transition bin through a valve. The bottom of the powder storage bin is provided with an openable and closable sealing door, and the powder storage bin can convey powder to the receiving hopper through the sealing door; A sealing cover is provided on the top of the powder storage cylinder for connecting the outside world and the transition bin, and the sealing cover can block the gas flow between the transition bin and the outside world; The powder spreading assembly further includes a linear drive unit, which includes a scraper and a screw. The two screws are rotatably connected to the inner walls of the two sides of the gas protection box through a support, and the two sides of the scraper are respectively screwed to the screws, and the screw can drive the scraper to move linearly. The powder discharging unit comprises a flap, an elastic member and a guide wheel. The bottom of the powder placing box is provided with an opening. The middle part of the flap is hinged to one side of the opening. The end of the flap close to the scraper is connected to the powder placing box through an elastic member so that the flap can automatically close the opening. The guide wheels are arranged on both sides of the other end of the flap, and bosses cooperating with the guide wheels are arranged on both sides of the inner wall of the gas protection box, and protrusions for moving the flap are arranged on the bosses; A flow divider is provided inside the powder placing box, and a plurality of the flow dividers are arranged around the receiving hopper. The flow divider can guide the powder to be evenly laid on the flap.

2. A powder-adding SLM powder spreading device according to claim 1, It is characterized in that The transition chamber is provided with a second interface for accessing inert gas.

3. A powder-adding SLM powder spreading device according to claim 1, It is characterized in that The bottom of the scraper is in contact with the workbench, the powder box is located between the two screws, the side of the powder box is fixedly connected to the side of the scraper, and the bottom of the powder box is spaced apart from the workbench.

4. A powder-adding SLM powder spreading device according to claim 3, It is characterized in that A forming cylinder is arranged in the gas protection box, the forming cylinder is embedded in the workbench, the forming cylinder is located on the moving path of the powder placing box, and a retractable piston is arranged in the forming cylinder.

5. A powder-adding SLM powder spreading device according to claim 4, It is characterized in that A recovery cylinder is provided between the molding cylinder and the inner wall of the gas protection box. The recovery cylinder is located on a side of the molding cylinder away from the powder placing box, and the recovery cylinder is embedded in the workbench.

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