Metal powder printing device and working method thereof

Abstract

The present invention discloses a metal powder spreading printing device and a working method thereof, wherein the metal powder spreading printing device comprises a frame, a laser, a powder spreading module, and a printing platform, wherein the laser, the powder spreading module, and the printing platform are sequentially installed on the frame from top to bottom, wherein the powder spreading module is used for metal powder to fall from top to bottom to the printing platform and realize the scraping action through a scraper rotating around a central axis; the printing platform is used for carrying a workpiece and synchronously descending vertically and linearly in the process of cooperating with the powder spreading module to realize the powder spreading work of the powder spreading module; the driving mechanism is used for synchronously driving the powder box rotation of the powder spreading module and the vertical linear descent of the printing platform in the printing state. The present invention can realize the simultaneous powder spreading and laser beam, thereby improving the working efficiency of the metal powder spreading 3D printing device.

Description

Technical Field

[0001] The invention relates to the field of metal powder product processing, and in particular to a metal powder printing device. Background Art

[0002] The working process of the metal powder printing device (SLM metal printing device) is as follows: a thin layer of metal powder is spread on the platform, and the cross-section of the component is scanned with a laser to melt (or fuse) the metal particles together to complete the printing of the current layer of data. After the previous layer is printed, the printing platform moves down one layer thickness, and the scraper moves across the platform to deposit the next layer of powder into the inert printing chamber. Then another layer of metal powder is spread again. This process is repeated layer by layer until the printing is completed. Since the scraper moves across the platform in a horizontal motion, it takes a long time to move back and forth. The Chinese invention patent with application number 201811564012.1 discloses a 3D printing powder spreading system, a 3D printing device and a 3D printing powder spreading method. The 3D printing powder spreading system includes a disc-shaped powder spreading table, a first cylindrical powder trough wall, a scraper rotating shaft and a plurality of main scrapers. The lower edge of the first cylindrical powder trough wall is sealed and connected to the upper surface of the disc-shaped powder spreading table. A through hole is provided in the center of the disc-shaped powder spreading table. The scraper rotating shaft is penetrated in the through hole. One end of the plurality of main scrapers is fixedly connected to the scraper rotating shaft. The scraper rotating shaft drives the plurality of main scrapers to rotate unidirectionally. The disc-shaped powder spreading table is also provided with at least one powder spreading port. The powder is sent out from the powder spreading port through the unidirectional rotation of the main scraper. The powder spreading efficiency of the 3D printing powder spreading system is improved. At the same time, the unidirectional rotation of the scraper rotating shaft also reduces the printing risk, so that the main scraper can inherit the powder scraped off by the previous main scraper and continue to be used for the next layer of powder spreading, realizing continuous powder spreading and improving the powder utilization rate. Like the traditional powder laying method, this equipment requires that after the current layer of powder is laid, the substrate lifting unit drives the substrate to descend by one layer of powder thickness according to the work flow, and then proceeds to lay the next layer of powder. It also has the same traditional working steps: substrate lowering, powder laying and leveling, and laser hot melting steps are performed in sequence. There is also a consumption of time in the connection of each link, and because the main scraper is in the stopped state during the laser hot melting process, it occupies the cross-sectional contour area required for printing, which to a certain extent affects the laser projection focus on the cross-sectional contour area. Summary of the invention

[0003] The purpose of the present invention is to provide a metal powder printing device. The metal powder printing device of the present invention can reduce the connection time of the traditional substrate lowering, powder leveling and laser hot melting process, and shorten the production cycle of the processing.

[0004] The technical solution adopted by the present invention to solve the above problems is:

[0005] A metal powder spreading printing device, characterized in that: a metal powder spreading 3D printing device, comprising a frame, a laser, a powder spreading module, and a printing platform, wherein the laser, the powder spreading module, and the printing platform are sequentially installed on the frame from top to bottom, wherein the powder spreading module is used to drop metal powder from top to bottom onto the printing platform and realize a scraping action through a scraper rotating around a central axis;

[0006] The printing platform is used to carry the workpiece and to vertically descend synchronously with the movement of the powder spreading module to realize the powder spreading work of the powder spreading module;

[0007] The driving mechanism is used to drive the powder box of the powder laying module to rotate and the printing platform to descend vertically in a synchronous manner under the printing state.

[0008] Further, as a preference, the powder spreading module comprises a silo, a powder box, a scraper and a roller, the silo adopts a vertically straight structure, the powder box is rotatably mounted on the silo, the silo is fixed on the frame, a long strip-shaped powder outlet hole is provided at the lower end of the powder box, the roller is rotatably mounted in the powder box, a strip-shaped slot is provided on the surface of the roller, a servo motor for driving the roller to rotate is fixed on the powder box, the axis of the roller is horizontally arranged, and the lower edge of the roller extends downward from the powder outlet hole to the lower end of the powder box, the scraper is fixed on the powder box, and in the rotation direction of the powder box, the scraper is located behind the roller, and the axis of the roller and the blade line of the scraper are arranged in parallel,

[0009] Further, as a preference, the printing platform includes a support platform and a support frame, the support platform is fixed on the support frame, the support frame is vertically slidably installed on the frame, the support frame and the frame are connected by a screw-nut mechanism, the support frame is located in the hollow cavity of the silo, and the support frame can be moved up and down relative to the silo and the scraper by the screw-nut mechanism.

[0010] Further, preferably, there is an annular gap between the support platform and the silo.

[0011] Further, as a preference, the drive mechanism includes a servo drive motor, a screw-nut mechanism, a first gearbox, a second gearbox and a first electromagnetic clutch, the ring gear is connected to the first gearbox, the first gearbox is connected to the first electromagnetic clutch, the first electromagnetic clutch is connected to the servo drive motor, the screw-nut mechanism is connected to the second gearbox, and the second gearbox is connected to the servo drive motor.

[0012] Further, as a preferred embodiment, the structure of the driving mechanism is as follows: the lower vertical transmission shaft is fixed to one end of the first electromagnetic clutch, the other end of the first electromagnetic clutch is fixed to the upper vertical transmission shaft, the upper vertical moving shaft is fixed to the input shaft of the first gearbox, and the output shaft of the first gearbox drives the gear ring to rotate through the gear. The outer horizontal transmission shaft is connected to the vertical lower straight transmission shaft through a bevel gear set to realize the synchronous rotation of the outer horizontal transmission shaft and the lower vertical transmission shaft, the servo drive motor fixes the outer horizontal transmission shaft, the outer horizontal transmission shaft is fixed to one end of the second electromagnetic clutch, the other end of the second electromagnetic clutch is fixed to the inner horizontal transmission shaft, the inner horizontal transmission shaft fixes the input shaft of the second gearbox, and the output shaft of the second gearbox drives the screw of the screw nut mechanism to rotate, the screw of the screw nut mechanism is rotatably mounted on the frame, and the nut of the screw nut mechanism is rotatably mounted on the support frame, and the power of the servo drive motor is sequentially transmitted to the screw through the outer horizontal transmission shaft, the second electromagnetic clutch, the inner horizontal transmission shaft, and the second gearbox, so that the screw rotates, thereby realizing the vertical linear movement of the nut of the screw nut mechanism.

[0013] Further, as a preference, the supporting platform comprises an upper base plate, a lower base plate, a lower locking piece and an upper locking piece. The upper base plate is fixed to the top of the lower base plate. A through hole is provided in the central area of ​​the upper base plate. The lower locking piece passes through the through hole of the upper base plate. The upper locking piece is tightened on the lower locking piece by threaded fitting. The outer wall of the upper locking piece is provided with an inclined pressing surface for pressing on the inclined table surface. A positioning groove for inserting a positioning pin is provided on the upper surface of the upper base plate.

[0014] Furthermore, as a preference, it also includes a powder recovery module, which includes a recovery bin with an annular groove, the recovery ring cylinder is fixed on the frame, the annular groove of the recovery ring cylinder is located below the gap between the support platform and the bin cylinder, so that the metal powder at the outer end of the scraper is brought into the gap between the support platform and the bin cylinder and falls into the recovery bin, and a plurality of external recovery pipes are fixedly connected to the bottom of the annular groove.

[0015] Further, as a preference, a through hole is opened in the central area of ​​the lower locking member and the lower base plate, and the through hole of the lower base plate is fixed and connected to the inner recovery pipe.

[0016] A working method based on the above-mentioned metal powder printing device includes the following steps:

[0017] (1) Workpiece clamping process: disconnect the first electromagnetic clutch, connect the second electromagnetic clutch, and transmit the power of the servo drive motor to the lead screw through the outer horizontal transmission shaft, the second electromagnetic clutch, the inner horizontal transmission shaft, and the second gearbox in sequence, so that the lead screw rotates and drives the support platform to descend, thereby facilitating the clamping of the annular workpiece.

[0018] (2) Tool setting process: disconnect the first electromagnetic clutch and connect the second electromagnetic clutch. The power of the servo drive motor is transmitted to the lead screw through the outer horizontal transmission shaft, the second electromagnetic clutch, the inner horizontal transmission shaft, and the second gearbox in sequence, so that the lead screw rotates and drives the support platform to rise, thereby realizing the tool setting action.

[0019] (3) Powder printing process: turn on the first electromagnetic clutch, turn on the second electromagnetic clutch, and use the power of the servo drive motor to transmit the power to the lead screw through the outer horizontal transmission shaft, the second electromagnetic clutch, the inner horizontal transmission shaft, and the second gearbox in sequence, so that the lead screw rotates and drives the support platform to descend. At the same time, the power of the servo drive motor is transmitted through the outer horizontal transmission shaft, the bevel gear set, the lower vertical transmission shaft, the first electromagnetic clutch, the upper vertical transmission shaft, the first gearbox, and the gear to drive the gear ring to rotate, thereby realizing the rotation of the scraper. At the same time, the focus projected by the laser of the metal powder printing equipment also changes with the direction of rotation of the scraper. In this process, while the scraper of the powder spreading module rotates around the central axis, the focus projected by the laser of the metal powder spreading printing equipment on the surface of the metal powder also changes with the direction of rotation of the scraper, so that the laser beam can follow the movement of the scraper to continuously sinter the metal powder in the scraped area.

[0020] (4) Workpiece removal process: disconnect the first electromagnetic clutch, connect the second electromagnetic clutch, and transmit the power of the servo drive motor to the lead screw through the outer horizontal transmission shaft, the second electromagnetic clutch, the inner horizontal transmission shaft, and the second gearbox in sequence, so that the lead screw rotates and drives the support platform to descend, thereby facilitating the removal of the workpiece.

[0021] (5) Metal powder recovery process: After removing the workpiece, the first electromagnetic clutch is turned on, the second electromagnetic clutch is turned on, and the second electromagnetic clutch is turned on. The power of the servo drive motor is transmitted to the screw through the outer horizontal transmission shaft, the second electromagnetic clutch, the inner horizontal transmission shaft, and the second gearbox in sequence, so that the screw rotates and drives the support platform to rise. At the same time, the power of the servo drive motor is transmitted to the ring gear through the outer horizontal transmission shaft, the bevel gear set, the lower vertical transmission shaft, the first electromagnetic clutch, the upper vertical transmission shaft, the first gearbox, and the gear in sequence, thereby realizing the reverse rotation of the scraper. The metal powder is pushed into the gap between the support platform and the silo by the scraper and falls into the recovery bin and is pushed into the through hole in the central area of ​​the lower locking member and the lower substrate by the scraper to enter the inner recovery pipe, thereby realizing the automatic recovery of the metal powder.

[0022] Compared with the prior art, the present invention has the following advantages and effects: the metal powder spreading grafting printing equipment synchronously drives the powder spreading module and the printing platform, which not only has a simple control logic, but also has a high degree of synchronization between the powder spreading module and the printing platform, which is conducive to improving the control accuracy, and can realize the rotation of the powder spreading and scraping and the synchronous descent of the supporting platform. The laser controls the laser beam to melt the metal alloy powder along the rotation direction of the powder spreading and scraping, and stack it into a dense workpiece. Since the existing powder spreading mechanism consumes a lot of time in the cyclic manufacturing process of layer-by-layer superposition, since the powder spreading and the laser beam work sequentially. The present invention adopts the above-mentioned driving mechanism to realize the simultaneous operation of powder spreading and laser beam, thereby improving the working efficiency of the metal powder spreading 3D printing equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of a metal powder 3D printing device according to an embodiment of the present invention.

[0024] Figure 2 It is a schematic diagram of the internal structure of the metal powder 3D printing device according to an embodiment of the present invention.

[0025] Figure 3 It is a structural schematic diagram of a powder spreading module according to an embodiment of the present invention.

[0026] Figure 4 It is a schematic diagram of the installation structure of the scraper according to an embodiment of the present invention.

[0027] Figure 5 It is a schematic diagram of the structure of the recovery bin according to an embodiment of the present invention.

[0028] Figure 6 Embodiment of the present invention Figure 2 Schematic diagram of the enlarged structure at point A in the middle.

[0029] Figure 7 Embodiment of the present invention Figure 2 Schematic diagram of the enlarged structure at point B in the middle.

[0030] Figure 8 Schematic diagram of the scraper position change during the printing process of an embodiment of the present invention.

[0031] Figure numerals: forming bin 1, frame 2, laser 3, bin tube 41, powder box 42, scraper 43, roller 44, slot 45, gear ring 46, gap 47, support platform 51, support frame 52, upper base plate 54, lower base plate 55, lower locking member 56, upper locking member 57, oblique pressing surface 58, positioning groove 59, servo drive motor 61, lower vertical transmission shaft 62, first electromagnetic clutch 63, upper vertical transmission shaft 64, first gearbox 65, bevel gear set 66, outer horizontal transmission shaft 67, second electromagnetic clutch 68, inner horizontal transmission shaft 69, second gearbox 610, screw 611, recovery bin 71, annular groove 72, outer recovery pipe 73, inner recovery pipe 74, bellows sleeve 75, through holes 81, 81, 83, 93, annular workpiece 9, positioning pin 91, oblique table 92 DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and by way of examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0033] See also Figure 1-8 The metal powder spreading 3D printing device of this embodiment includes a molding chamber 1, a frame 2, a laser 3, a powder spreading module, and a printing platform. The laser 3, the powder spreading module, and the printing platform are installed on the frame 2 from top to bottom in sequence.

[0034] The powder spreading module includes a silo 41, a powder box 42, a scraper 43 and a roller 44. The silo 41 adopts a vertical straight structure. The powder box 42 is rotatably installed on the silo 41, and the silo 41 is fixed on the frame 2. A long strip powder outlet hole is provided at the lower end of the powder box 42. The roller 44 is rotatably installed in the powder box 42. A strip slot 45 is provided on the surface of the roller 44. A servo motor for driving the roller 44 to rotate is fixed on the powder box 42. The axis of the roller 44 is horizontally arranged, and the lower edge of the roller 44 extends downward from the powder outlet hole to the lower end of the powder box 42. The scraper 43 is fixed on the powder box 42, and in the rotation direction of the powder box 42, the scraper 43 is located behind the roller 44, and the axis of the roller 44 and the blade line of the scraper 43 are arranged in parallel.

[0035] As a preferred embodiment, in this embodiment, Figure 5 As shown, a gear ring 46 (the axis of the gear ring 46 is the central axis) is coaxially mounted on the silo 41, and the powder box 42 is fixed to the gear ring 46, so that the powder box 42 has a degree of freedom relative to the silo 41.

[0036] The printing platform includes a support platform 51 and a support frame 52. The support platform 51 is fixed on the support frame 52. The support frame 52 is vertically slidably installed on the frame 2. The support frame 52 and the frame 2 are connected by a screw-nut mechanism. The support frame 52 is located in the hollow cavity of the silo 41, and the support frame 52 is moved up and down relative to the silo 41 and the scraper 43 by the screw-nut mechanism.

[0037] Preferably, in this embodiment, there is an annular gap 47 between the support platform 51 and the silo 41 (see Figure 3 ).

[0038] The driving mechanism includes a servo driving motor 61, a screw-nut mechanism, a first gearbox 65, a second gearbox 610 and a first electromagnetic clutch 63. The ring gear 46 is connected to the first gearbox 65, the first gearbox 65 is connected to the first electromagnetic clutch 63, the first electromagnetic clutch 63 is connected to the servo driving motor 61, the screw-nut mechanism is connected to the second gearbox 610, and the second gearbox 610 is connected to the servo driving motor 61.

[0039] The above-mentioned driving method can not only drive the gear ring 46 to rotate via the servo drive motor 61 through the first gearbox 65, thereby realizing the central rotation of the powder box 42, the scraper 43, and the roller 44 relative to the silo 41, but also the servo drive motor 61 drives the screw nut mechanism to start working via the second gearbox 610, thereby realizing the up and down movement of the support frame 52 relative to the scraper 43. Since the servo drive motor 61 can synchronously drive the powder spreading module and the printing platform, not only the control logic is simple, but also the powder spreading module and the printing platform have high synchronization, which is conducive to improving the control accuracy, and the rotation of the powder spreading and the synchronous descent of the support platform 51 can be realized. The laser 3 controls the laser beam to melt the metal alloy powder along the rotation direction of the powder spreading and the laser beam to stack into the upper half of the dense workpiece. Because the existing powder spreading mechanism consumes a lot of time in the cyclic manufacturing process of layer-by-layer superposition, the powder spreading and the laser beam work in sequence. The present invention adopts the above-mentioned driving mechanism to realize the simultaneous powder spreading and laser beam, thereby greatly improving the working efficiency of the metal powder spreading 3D printing equipment.

[0040] However, it should be noted that, since the existing SLM technology generally slices the three-dimensional model and adds support and layering processing to obtain the cross-sectional contour data of the three-dimensional model; the contour data is scanned path processing using path planning software, and the data after path planning is imported into the SLM device. During the operation of the metal powder 3D printing device of the present invention, the laser beam works around the center of the silo 41 after the scraper 43, and the focus of the laser beam is not in the same plane. There is a 0.01mm-0.05mm or even larger drop between the lowest point and the highest point (depending on the manufacturing accuracy of the equipment), which has a certain negative impact on the progress of 3D printing, but it improves the processing efficiency of the equipment, and the dimensional accuracy can be corrected through subsequent machining, and for workpieces that do not require particularly high processing accuracy (the processing tolerance allows 0.05mm or even 0.1mm or more), the metal powder 3D printing device of the present invention has obvious advantages in terms of processing efficiency.

[0041] Since the scraper 43 of the metal powder 3D printing device is rotating and scraping, there will be a little accumulation of metal powder in the rotation center point area that cannot be scraped flat. Therefore, the metal powder 3D printing device is suitable for 3D printing of some workpieces with center holes (such as annular workpieces). The center hole avoids the metal powder in the rotation center point area. For non-annular workpieces, they need to be arranged in an area away from the center axis for printing.

[0042] As a preferred embodiment, in this embodiment, Figure 2 As shown, the lower vertical transmission shaft 62 is fixed to one end of the first electromagnetic clutch 63, the other end of the first electromagnetic clutch 63 is fixed to the upper vertical transmission shaft 64, the upper vertical movable shaft is fixed to the input shaft of the first gearbox 65, and the output shaft of the first gearbox 65 drives the ring gear 46 to rotate through the gear. The outer horizontal transmission shaft 67 is connected to the lower vertical transmission shaft through a bevel gear set 66 to realize the synchronous rotation of the outer horizontal transmission shaft 67 and the lower vertical transmission shaft 62. The servo drive motor 61 fixes the outer horizontal transmission shaft 67. The outer horizontal transmission shaft 67 is fixed to one end of the second electromagnetic clutch 68. The other end of the second electromagnetic clutch 68 is fixed to the inner horizontal transmission shaft 69. The inner horizontal transmission shaft 69 fixes the input shaft of the second gearbox 610. The output shaft of the second gearbox 610 drives the screw 611 of the screw nut mechanism to rotate. The screw 611 of the screw nut mechanism is rotatably installed on the frame 2, and the nut of the screw nut mechanism is rotatably installed on the support frame 52. The power of the servo drive motor 61 is sequentially transmitted to the screw 611 through the outer horizontal transmission shaft 67, the second electromagnetic clutch 68, the inner horizontal transmission shaft 69, and the second gearbox 610, so that the screw 611 rotates, thereby realizing the vertical linear movement of the nut of the screw nut mechanism.

[0043] By adopting the above-mentioned driving mechanism and setting two electromagnetic clutches (first electromagnetic clutch 63 and second electromagnetic clutch 68), the following process steps can be realized:

[0044] (1) When clamping a workpiece: disconnect the first electromagnetic clutch 63, connect the second electromagnetic clutch 68, and transmit the power of the servo drive motor 61 to the screw rod 611 in sequence through the outer horizontal transmission shaft 67, the second electromagnetic clutch 68, the inner horizontal transmission shaft 69, and the second gearbox 610, so that the screw rod 611 rotates, driving the support platform 51 to descend, thereby facilitating the clamping of the workpiece.

[0045] (2) When setting the tool: disconnect the first electromagnetic clutch 63, connect the second electromagnetic clutch 68, and transmit the power of the servo drive motor 61 to the screw rod 611 through the outer horizontal transmission shaft 67, the second electromagnetic clutch 68, the inner horizontal transmission shaft 69, and the second gearbox 610 in sequence, so that the screw rod 611 rotates, driving the support platform 51 to rise, thereby realizing the tool setting action.

[0046] (3) When printing with powder: turn on the first electromagnetic clutch 63, turn on the second electromagnetic clutch 68, and the power of the servo drive motor 61 is transmitted to the screw 611 through the outer horizontal transmission shaft 67, the second electromagnetic clutch 68, the inner horizontal transmission shaft 69, and the second gearbox 610 in sequence, so that the screw 611 rotates and drives the support platform 51 to descend. At the same time, the power of the servo drive motor 61 is transmitted through the outer horizontal transmission shaft 67, the bevel gear set 66, the lower vertical transmission shaft 62, the first electromagnetic clutch 63, the upper vertical transmission shaft 64, the first gearbox 65, and the gear to drive the gear ring 46 to rotate, thereby realizing the rotation of the scraper 43. Figure 8 As shown, when the scraper 43 is at position P1, the focal projection area of ​​the laser 3 is located at P3. When the scraper 43 rotates to P2 along the direction shown in the figure, the focal projection area of ​​the laser 3 also follows and moves to P3, and the process is repeated in sequence to achieve continuous printing. In this process, while the scraper 43 of the powder spreading module rotates cyclically around the central axis, the focus of the laser 3 of the metal powder spreading printing device projected on the surface of the metal powder also changes with the rotation direction of the scraper 43 to achieve the change of the focal projection area, so that the laser beam can follow the movement of the scraper 43 to continuously sinter the metal powder in the scraped area of ​​the scraper 43. In this process, the support platform 51 carrying the workpiece moves downward synchronously. The present invention adopts the above method to carry out powder spreading and laser beam simultaneously, thereby greatly improving the working efficiency of the metal powder spreading 3D printing device for metal powder printing, and the focal projection area of ​​the laser 3 also moves with the rotation of the rotating scraper 43, so that during the laser hot melting process, the main scraper 43 will not occupy the cross-sectional contour area required for hot melting of the laser 3 focus.

[0047] (4) When the printing is completed and the workpiece is removed: the first electromagnetic clutch 63 is disconnected, and the second electromagnetic clutch 68 is connected. The power of the servo drive motor 61 is transmitted to the screw rod 611 through the outer horizontal transmission shaft 67, the second electromagnetic clutch 68, the inner horizontal transmission shaft 69, and the second gearbox 610 in sequence, so that the screw rod 611 rotates, driving the support platform 51 to descend, thereby facilitating the removal of the workpiece.

[0048] Furthermore, in this embodiment, in order to facilitate the grafting and printing of some larger annular workpieces 9 (such as the middle ring of the granulation template), and the apertures of the upper and lower sections of such annular workpieces 9 are consistent, in order to improve the convenience of clamping the annular workpiece 9 of the base part before grafting and printing, as shown in FIG. Figure 6 As shown, during the machining process of the annular workpiece 9 of the base portion, a truncated cone-shaped positioning pin 91 located on the bottom surface of the annular workpiece 9 and an inclined table surface 92 located on the inner wall of the through hole 93 of the annular workpiece 9 can be machined. The support platform 51 includes an upper base plate 54, a lower base plate 55, a lower locking member 56, and an upper locking member 57. The upper base plate 54 is fixed to the top of the lower base plate 55. A through hole 83 is provided in the central area of ​​the upper base plate 54. The lower locking member passes through the through hole 83 of the upper base plate 54. The upper locking member 57 is tightened on the lower locking member 56 by threaded engagement. The outer wall of the upper locking member 57 is provided with an inclined pressing surface 58 for pressing on the inclined table surface 92. The upper surface of the upper base plate 54 is provided with a positioning groove 59 for inserting the positioning pin 91. The positioning pin 91 and the inclined table surface 92 need to be removed by a CNC machine tool after the subsequent machining process.

[0049] During the clamping process of the annular workpiece 9, the annular workpiece 9 is placed on the upper base plate 54, and the positioning pin 91 of the annular workpiece 9 is inserted into the positioning groove 59 to realize the positioning of the annular workpiece 9. Then, the upper locking member 57 is screwed on the lower locking member 56 through threaded cooperation, and the oblique pressing surface 58 of the upper locking member 57 is pressed on the oblique table surface 92 of the annular workpiece 9, thereby completing the positioning and clamping of the annular workpiece 9. When the upper locking member 57 is removed, the upper locking member 57 can be taken out from the upper end of the workpiece (the size of the upper locking member 57 should be smaller than the central aperture of the annular workpiece).

[0050] Furthermore, in order to solve the problem of metal powder recovery in the metal powder 3D printing equipment, in this embodiment, the metal powder 3D printing equipment also includes a powder recovery module, and the powder recovery module includes a recovery bin 71 with an annular groove 72. The recovery ring cylinder is fixed on the frame 2, and the annular groove 72 of the recovery ring cylinder is located below the gap 47 between the support platform 51 and the bin cylinder 41, so that the metal powder at the outer end of the scraper 43 is brought into the gap 47 between the support platform 51 and the bin cylinder 41 and falls into the recovery bin 71. A plurality of external recovery pipes 73 are fixedly connected to the bottom of the annular groove 72.

[0051] The lower locking member 56 and the central area of ​​the lower base plate 55 are respectively provided with a through hole 81 and a through hole 82. The through hole 82 of the lower base plate 55 is fixed and connected to the inner recovery pipe 74. The outer recovery pipe 73 and the inner recovery pipe 74 are connected to the filtering and recovery system of the metal powder via a negative pressure vacuum device, and are used for the metal powder to be filtered and then recycled. In order to prevent the metal powder in the recovery bin 71 from escaping, a bellows sleeve 75 is provided on the outer wall of the recovery bin 71. The lower end of the bellows sleeve 75 is fixed to the outer wall of the recovery bin 71, and the upper end of the bellows sleeve 75 is fixed to the lower surface of the upper top plate of the frame 2.

[0052] By adopting the above-mentioned driving mechanism and setting two electromagnetic clutches (first electromagnetic clutch 63 and second electromagnetic clutch 68), the following process steps can be realized:

[0053] Metal powder recovery: After removing the workpiece, the first electromagnetic clutch 63 is turned on, the second electromagnetic clutch 68 is turned on, and the power of the servo drive motor 61 is sequentially transmitted through the outer horizontal transmission shaft 67, the second electromagnetic clutch 68, the inner horizontal transmission shaft 69, and the second gearbox 610 to the screw rod 611, so that the screw rod 611 rotates, driving the support platform 51 to rise. At the same time, the power of the servo drive motor 61 is sequentially transmitted through the outer horizontal transmission shaft 67, the bevel gear set 66, the lower vertical transmission shaft 69, and the lower vertical transmission shaft 610. The moving shaft 62, the first electromagnetic clutch 63, the upper vertical transmission shaft 64, the first gearbox 65, and the gear drive the ring gear 46 to rotate, thereby realizing the reverse (relative to the above-mentioned powder printing) rotation of the scraper 43. The metal powder is pushed by the scraper 43 into the gap 47 between the supporting platform 51 and the silo 41 and falls into the recovery bin 71. The scraper 43 also pushes the lower locking piece 56 and the through hole 82 in the center area of ​​the lower base plate 55 into the internal recovery tube 74 (the workpiece needs to be removed before operation), thereby realizing the automatic recovery of the metal powder.

[0054] The above contents described in this specification are merely examples of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, as long as they do not deviate from the contents of the present specification or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A metal powder spreading printing device, comprising a frame, a laser, a powder spreading module, and a printing platform, wherein the laser, the powder spreading module, and the printing platform are sequentially installed on the frame from top to bottom, and characterized in that: The powder spreading module is used to drop metal powder from top to bottom onto the printing platform and achieve the leveling action through a scraper rotating around the central axis; The printing platform is used to carry the workpiece and to vertically descend synchronously with the movement of the powder spreading module to realize the powder spreading work of the powder spreading module; A driving mechanism, which is used to drive the powder box of the powder spreading module to rotate and the printing platform to descend vertically in a synchronous manner in a printing state; The powder spreading module comprises a silo, a powder box, a scraper and a roller. The silo adopts a vertically straight structure. The powder box is rotatably mounted on the silo, which is fixed on a frame. A long strip-shaped powder outlet hole is provided at the lower end of the powder box. The roller is rotatably mounted in the powder box. A strip-shaped slot is provided on the surface of the roller. A servo motor for driving the roller to rotate is fixed on the powder box. The axis of the roller is horizontally arranged, and the lower edge of the roller extends downward from the powder outlet hole to be exposed to the lower end of the powder box. The scraper is fixed on the powder box, and in the rotation direction of the powder box, the scraper is located behind the roller, and the axis of the roller and the blade line of the scraper are arranged in parallel. The structure of the driving mechanism is as follows: the lower vertical transmission shaft is fixed to one end of the first electromagnetic clutch, the other end of the first electromagnetic clutch is fixed to the upper vertical transmission shaft, the upper vertical moving shaft is fixed to the input shaft of the first gearbox, the output shaft of the first gearbox drives the gear ring to rotate through the gear, the outer horizontal transmission shaft is connected to the vertical lower transmission shaft through the bevel gear set to realize the synchronous rotation of the outer horizontal transmission shaft and the lower vertical transmission shaft, the servo drive motor fixes the outer horizontal transmission shaft, the outer horizontal transmission shaft is fixed to one end of the second electromagnetic clutch, the other end of the second electromagnetic clutch is fixed to the inner horizontal transmission shaft, the inner horizontal transmission shaft fixes the input shaft of the second gearbox, the output shaft of the second gearbox drives the screw of the screw nut mechanism to rotate, the screw of the screw nut mechanism is rotatably installed on the frame, and the nut of the screw nut mechanism is rotatably installed on the support frame, and the power of the servo drive motor is sequentially transmitted to the screw through the outer horizontal transmission shaft, the second electromagnetic clutch, the inner horizontal transmission shaft, and the second gearbox, so that the screw rotates, thereby realizing the vertical linear movement of the nut of the screw nut mechanism.

2. The metal powder printing device according to claim 1, characterized in that: The printing platform includes a support platform and a support frame. The support platform is fixed on the support frame. The support frame is vertically slidably installed on the frame. The support frame and the frame are connected by a screw-nut mechanism. The support frame is located in the hollow cavity of the silo, and the screw-nut mechanism is used to realize the up and down movement of the support frame relative to the silo and the scraper.

3. The metal powder printing device according to claim 2, characterized in that: There is an annular gap between the support platform and the silo.

4. The metal powder printing device according to claim 1, characterized in that: The drive mechanism includes a servo drive motor, a screw-nut mechanism, a first gearbox, a second gearbox and a first electromagnetic clutch, the ring gear is connected to the first gearbox, the first gearbox is connected to the first electromagnetic clutch, the first electromagnetic clutch is connected to the servo drive motor, the screw-nut mechanism is connected to the second gearbox, and the second gearbox is connected to the servo drive motor.

5. The metal powder printing device according to claim 2, characterized in that: The supporting platform includes an upper base plate, a lower base plate, a lower locking piece, and an upper locking piece. The upper base plate is fixed to the top of the lower base plate. A through hole is opened in the central area of ​​the upper base plate. The lower locking piece passes through the through hole of the upper base plate. The upper locking piece is tightened on the lower locking piece by threaded fitting. The outer wall of the upper locking piece is provided with an inclined pressing surface for pressing on the inclined table surface. A positioning groove for inserting a positioning pin is opened on the upper surface of the upper base plate.

6. The metal powder printing device according to claim 1, characterized in that: It also includes a powder recovery module, which includes a recovery bin with an annular groove. The recovery ring cylinder is fixed on the frame. The annular groove of the recovery ring cylinder is located below the gap between the support platform and the bin cylinder, so that the metal powder at the outer end of the scraper is brought into the gap between the support platform and the bin cylinder and falls into the recovery bin. A number of external recovery pipes are fixedly connected to the bottom of the annular groove.

7. The metal powder printing device according to claim 5, characterized in that: A through hole is provided in the central area of ​​the lower locking piece and the lower base plate, and the through hole of the lower base plate is fixed and connected to the inner recovery pipe.

8. A working method of the metal powder printing device according to any one of claims 1 to 7 comprises the following steps: (1) Workpiece clamping process: disconnect the first electromagnetic clutch, connect the second electromagnetic clutch, and transmit the power of the servo drive motor to the lead screw through the outer horizontal transmission shaft, the second electromagnetic clutch, the inner horizontal transmission shaft, and the second gearbox in sequence, so that the lead screw rotates and drives the support platform to descend, thereby facilitating the clamping of the workpiece; (2) Tool setting process: disconnect the first electromagnetic clutch, connect the second electromagnetic clutch, and transmit the power of the servo drive motor to the lead screw through the outer horizontal transmission shaft, the second electromagnetic clutch, the inner horizontal transmission shaft, and the second gearbox in sequence, so that the lead screw rotates and drives the support platform to rise, thereby adjusting the upper surface of the workpiece to be flush with the lower edge of the scraper, thereby realizing the tool setting action; (3) Powder spreading and printing process: the first electromagnetic clutch is turned on, the second electromagnetic clutch is turned on, and the power of the servo drive motor is transmitted to the screw through the outer horizontal transmission shaft, the second electromagnetic clutch, the inner horizontal transmission shaft, and the second gearbox in sequence, so that the screw rotates and drives the support platform to descend. At the same time, the power of the servo drive motor is transmitted through the outer horizontal transmission shaft, the bevel gear set, the lower vertical transmission shaft, the first electromagnetic clutch, the upper vertical transmission shaft, the first gearbox, and the gear to drive the gear ring to rotate, thereby realizing the rotation of the scraper. At the same time, the focus projected by the laser of the metal powder spreading and printing equipment also changes with the rotation direction of the scraper. In this process, while the scraper of the powder spreading module rotates around the central axis, the focus projected by the laser of the metal powder spreading and printing equipment on the surface of the metal powder also changes with the rotation direction of the scraper, so that the laser beam can follow the movement of the scraper to continuously sinter the metal powder in the scraped area; (4) Workpiece removal process: disconnect the first electromagnetic clutch, connect the second electromagnetic clutch, and transmit the power of the servo drive motor to the screw rod through the outer horizontal transmission shaft, the second electromagnetic clutch, the inner horizontal transmission shaft, and the second gearbox in sequence, so that the screw rod rotates and drives the support platform to descend, thereby facilitating the removal of the workpiece; (5) Metal powder recovery process: After removing the workpiece, the first electromagnetic clutch is turned on, the second electromagnetic clutch is turned on, and the second electromagnetic clutch is turned on. The power of the servo drive motor is transmitted to the screw through the outer horizontal transmission shaft, the second electromagnetic clutch, the inner horizontal transmission shaft, and the second gearbox in sequence, so that the screw rotates and drives the support platform to rise. At the same time, the power of the servo drive motor is transmitted to the ring gear through the outer horizontal transmission shaft, the bevel gear set, the lower vertical transmission shaft, the first electromagnetic clutch, the upper vertical transmission shaft, the first gearbox, and the gear in sequence, thereby realizing the reverse rotation of the scraper. The metal powder is pushed into the gap between the support platform and the silo by the scraper and falls into the recovery bin and is pushed into the through hole in the central area of ​​the lower locking member and the lower substrate by the scraper to enter the inner recovery pipe, thereby realizing the automatic recovery of the metal powder.

Images