CN108327256B

CN108327256B - Bidirectional powder spreading device for powder printing

Info

Publication number: CN108327256B
Application number: CN201810348777.5A
Authority: CN
Inventors: 张新建; 牛莉; 段贤勇; 王甫; 孙燕; 张成林
Original assignee: Anhui Technical College of Mechanical and Electrical Engineering
Current assignee: Hefei Longzhi Electromechanical Technology Co ltd
Priority date: 2018-04-18
Filing date: 2018-04-18
Publication date: 2023-10-24
Anticipated expiration: 2038-04-18
Also published as: CN108327256A

Abstract

The invention relates to the field of 3D printing, in particular to a powder printing bidirectional powder spreading device which comprises a feeding device and a powder spreading device which are arranged in a printer shell, wherein the printer shell is divided into three parts by an upper partition plate and a lower partition plate, a supporting plate capable of moving up and down is arranged at the center of the upper partition plate, the bottom of the powder spreading device is attached to the upper end face of the upper partition plate, the powder spreading device can horizontally move at the top of the upper partition plate, the feeding device is positioned at the edge of the supporting plate, the powder spreading device comprises a third linear sliding table, a second sliding bar and a powder spreading device, and the feeding device comprises four powder boxes which are vertically arranged at two sides of the supporting plate and the discharging directions of all the powder boxes are vertically upwards.

Description

Bidirectional powder spreading device for powder printing

Technical Field

The invention relates to the field of 3D printing, in particular to a bidirectional powder spreading device for powder printing.

Background

3D prints (3 DP), namely a kind of rapid prototyping technology, it is a kind of technology based on digital model file, but use the binding material such as powdered metal or plastics, construct the object through the mode of printing layer by layer, the design process of three-dimensional printing is: modeling is performed through computer modeling software, and the built three-dimensional model is partitioned into cross sections layer by layer, namely slicing, so that a printer is guided to print layer by layer. The common printer used in daily life can print planar articles designed by a computer, the working principle of the 3D printer is basically the same as that of the common printer, the printing materials of the common printer are ink and paper, the 3D printer is filled with different printing materials such as metal, ceramic, plastic, sand and the like, the printing materials are real raw materials, and after the printer is connected with the computer, the printing materials can be overlapped layer by layer through computer control, and finally blueprints on the computer are changed into real objects. In colloquial terms, a 3D printer is a device that can "print" real 3D objects, such as a robot, a toy vehicle, various models, even food, etc. The term "printer" refers to the technical principle of a common printer, because the layering process is very similar to the inkjet printing, and the printing technology is called 3D stereoscopic printing technology. When the powder 3d printer of the current laser sintering technology is used for printing, a layer of powder needs to be paved on the surface of the current printing table, so that the laser heat source above the printing table is used for sintering printing, the traditional powder paving device mainly lays a layer of powder and then returns to the initial position to prepare for the next powder paving, and the process leads to the path forming process of the powder paving device, so that the printing efficiency is reduced.

Disclosure of Invention

The invention aims to provide a bidirectional powder spreading device for powder printing, which aims at overcoming the defects of the prior art.

In order to solve the problems, the invention provides the following technical scheme:

the utility model provides a two-way powder paving device that powder printed, including setting up the inside material feeding unit of printer casing and shop's powder device, the casing is vertical to be set up and its inner space is divided into triplex through last baffle and lower baffle, go up baffle and lower baffle all level setting, go up baffle and lower baffle interval arrangement in vertical direction, shop's powder device and material feeding unit are located the top below of last baffle respectively, the center department of going up the baffle is provided with one and can reciprocate the carrier plate, material feeding unit and the top intercommunication of last baffle and the up end of material feeding unit and last baffle are flush, shop's bottom and the up end laminating of last baffle and shop's powder device can be at the top horizontal migration of last baffle, material feeding unit is located carrier plate edge, shop's powder device includes third sharp slip table, second slide bar and shop's powder ware, shop's one end and the slider fixed connection of third sharp slip table, the other end and the cover that can slide are established on the second slide bar, material feeding unit is including four powder boxes of vertical setting up in the carrier plate both sides and the ejection of compact direction of all powder boxes is vertical upwards.

Preferably, the powder spreader comprises two bar-shaped scraping blocks and a connecting frame, wherein the two bar-shaped scraping blocks and the connecting frame are horizontally arranged, the two bar-shaped frames can vertically move on the inner side of the connecting frame, the two ends of the connecting frame are respectively connected with a third linear sliding table and a second sliding bar, the length direction of the bar-shaped scraping blocks is perpendicular to the length direction of the third linear sliding table, the bottom of each bar-shaped scraping block can be attached to the top of the upper partition plate, a plurality of sliding bars are arranged on the vertical side wall of each bar-shaped scraping block, and a plurality of sliding grooves in sliding fit with the sliding bars are formed in the inner side wall of the connecting frame.

Preferably, the inside of connecting frame is provided with a rotatable pivot, the axial of pivot is on a parallel with the length direction that the piece was scraped to the bar, the pivot is located the centre that two bars were scraped to the bar, a breach has been seted up at the middle part of connecting frame, be provided with a gear in the breach and this gear fixed cover is established in the pivot in inside, one side that two bars were scraped the piece and are close to each other all is provided with vertical rack, the gear meshes with two racks of both sides respectively, connecting frame's top is provided with a driving motor, driving motor is located one side tip top of pivot, be connected through a hold-in range transmission between driving motor's the output shaft and the pivot.

Preferably, each of the two ends of the strip-shaped scraping block is provided with a vertical accommodating cavity, each accommodating cavity is internally provided with a spring and a roller, each of the two ends of the spring is respectively abutted against the top of the accommodating cavity and the top of the roller, and the bottom of each roller can extend out of the accommodating cavity and be attached to the top of the upper partition plate.

Preferably, four the two pairs of powder boxes are located in the both sides of bearing plate, and every powder box is upper and lower open-ended structure, and the bottom of two powder boxes of every side all is provided with a vertical U type push pedal, and the bottom of every U type push pedal all is connected with lifting device, and lifting device fixed mounting is at the top of baffle down, and the top of every U type push pedal all can stretch into in the powder box that corresponds from bottom to top, and the upper half lateral wall of U type push pedal is laminated completely with the powder box inner wall that corresponds.

Preferably, the top of every the powder box all flushes with the up end of last baffle, and the top of every powder box is the hopper-shaped structure that falls, and the travel distance of third sharp slip table is greater than the distance between two powder boxes in the outside, and the length of piece is greater than the width of bearing board is scraped to the bar.

Preferably, the lifting device comprises a mounting shell, a screw rod, a worm, a turbine and a rotating motor, wherein the screw rod vertically penetrates the mounting shell, one end of the worm horizontally penetrates the mounting shell and is fixedly connected with the rotating motor, the turbine is sleeved on the screw rod, internal threads matched with the screw rod are arranged on the inner side wall of the turbine, the worm is meshed with the turbine, an extending shaft sleeve is arranged at the upper end and the lower end of the turbine, a bearing is sleeved on each extending shaft sleeve, an inner ring of the bearing is fixedly sleeved on the extending shaft sleeve, an outer ring of the bearing is fixedly connected with the inner wall of the mounting shell, and the bottoms of all the screws penetrate through the lower partition plate and extend downwards.

The beneficial effects are that: the invention relates to a powder printing bidirectional powder spreading device, which adds enough printing powder into four powder boxes through a filler funnel when in use, closes a door plate, enables equipment to work through a control key, lifts a U-shaped push plate by a certain distance, so that the U-shaped push plate pushes the printing powder in two powder boxes above out of an opening above, the printing powder is spread on the upper end face of a supporting plate by a strip-shaped scraping block in the horizontal movement process, then a driving motor drives a rotating shaft to rotate, the rotating shaft drives a gear to rotate, the gear rotates so that two meshed strip-shaped scraping blocks move in the vertical direction, when a powder spreader moves to the rightmost side through a third linear sliding table, the gear rotates positively, the left strip-shaped scraping block moves upwards, and the right strip-shaped scraping block moves downwards and is attached to the upper end face of an upper partition plate, at this time, the third linear sliding table drives the powder spreading device to move leftwards, so that powder sent out from the feeding device is spread on the upper end face of the supporting plate, after the laser finishes sintering printing of the layer, the supporting plate descends for a small distance, so that the upper end face of the supporting plate is still lower than the upper end face of the upper partition plate, smooth powder spreading is ensured, at this time, the gear is reversed, the left strip-shaped scraping block moves downwards until being attached to the upper end face of the upper partition plate, the right strip-shaped scraping block moves upwards, and the strip-shaped scraping block spreads powder sent out from the feeding device on the upper end face of the supporting plate under the driving of the third linear sliding table, so that powder can be spread at two ends of a printing area by reciprocation.

Drawings

FIG. 1 is a schematic perspective view of the present invention;

FIG. 2 is a schematic plan view of the present invention;

FIG. 3 is a schematic perspective view of the first embodiment of the present invention;

FIG. 4 is a schematic diagram of the present invention in a powder state;

FIG. 5 is a schematic diagram of a second aspect of the present invention;

FIG. 6 is an exploded perspective view of the present invention;

FIG. 7 is a plan cross-sectional view of the housing;

FIG. 8 is an exploded view of the three-dimensional structure of the bi-directional powder spreading device;

FIG. 9 is a top view of the connecting frame;

FIG. 10 is a plan cross-sectional view taken along line A-A of FIG. 9;

FIG. 11 is a partially exploded perspective view of the powder spreader;

FIG. 12 is a schematic view of a partial perspective view of a lifting device;

FIG. 13 is an exploded perspective view of FIG. 12;

reference numerals illustrate: the laser device comprises a machine shell 1, an upper partition plate 2, a lower partition plate 3, a supporting plate 4, a lifting device 5, a control box 6, a first linear sliding table 7, a second linear sliding table 8, a first sliding bar 9, a laser 10, a third linear sliding table 11, a second sliding bar 12, a powder spreader 13, a bar-shaped scraping block 14, a connecting frame 15, a sliding bar 16, a sliding groove 17, a rotating shaft 18, a notch 19, a rack 20, a driving motor 21, a synchronous belt 22, a containing cavity 23, a spring 24, a roller 25, a powder box 26, a U-shaped push plate 27, a lifting device 28, a mounting shell 29, a screw 30, a worm 31, a turbine 32, an extension sleeve 33, a lifting slide 34, a door plate 35, a transparent observation window 36, a filler funnel 37, a rotating motor 38 and a gear 39.

Detailed Description

Specific embodiments of the invention are described in further detail below with reference to the drawings and examples of the specification:

referring to a floor-type powder printer capable of bidirectionally laying powder shown in fig. 1 to 13, comprising a machine shell 1, a laser sintering mechanism, a bidirectionally laying powder mechanism and a bearing mechanism, wherein the laser sintering mechanism is located at the inner top of the machine shell 1, the machine shell 1 is vertically arranged and the inner space of the machine shell is divided into three parts by an upper partition plate 2 and a lower partition plate 3, the upper partition plate 2 and the lower partition plate 3 are horizontally arranged, the upper partition plate 2 and the lower partition plate 3 are vertically arranged at intervals, the bearing mechanism comprises a bearing plate 4 horizontally arranged and a lifting device 5 capable of vertically lifting, the bottom of the bearing plate 4 is fixedly connected with the output end of the top of the lifting device 5, the bearing plate 4 can vertically penetrate through the center of the upper partition plate 2, the upper end face of the bearing plate 4 is lower than the upper end face of the upper partition plate 2, the bidirectionally laying powder device comprises a feeding device arranged at the bottom of the upper partition plate 2 and a powder laying device arranged at the top of the upper partition plate 2, the feeding device is communicated with the upper side of the upper partition plate 2, the feeding device and the upper end face of the upper partition plate 2 are flush, the bottom of the powder device is attached to the upper end face of the upper end of the upper partition plate 2 and the upper end of the powder laying device can vertically move at the top of the upper partition plate 2, and the upper end of the supporting device is located at the top of the control box 6, and the control box is located at the top of the control device 1.

The laser sintering mechanism comprises a first linear sliding table 7, a second linear sliding table 8 and a first sliding rod 9, wherein the first linear sliding table 7 and the second linear sliding table 8 are mutually perpendicular, the first linear sliding table 7 and the first sliding rod 9 are mutually parallel, one end of the second linear sliding table 8 is fixedly connected with a sliding block of the first linear sliding table 7, the other end of the second linear sliding table 8 can be sleeved on the first sliding rod 9 in a sliding manner, a laser 10 is arranged on the sliding block of the second linear sliding table 8, the output direction of the laser 10 is vertical downwards, and the laser 10 can move flexibly in a working plane formed by the first linear sliding table 7 and the second linear sliding table 8.

The powder paving device comprises a third linear sliding table 11, a second sliding rod 12 and a powder paving device 13, one end of the powder paving device 13 is fixedly connected with a sliding block of the third linear sliding table 11, the other end of the powder paving device is sleeved on the second sliding rod 12 in a sliding manner, the powder paving device 13 is ensured to horizontally move on the upper end face of the upper partition plate 2, and the upper end face of the bearing plate 4 is always lower than the upper end face of the upper partition plate 2, so that powder is uniformly paved on the upper end face of the bearing plate 4.

The powder spreader 13 comprises two bar-shaped scraping blocks 14 and a connecting frame 15, the two bar-shaped scraping blocks 14 and the connecting frame 15 are horizontally arranged, the two bar-shaped frames can vertically move on the inner side of the connecting frame 15, two ends of the connecting frame 15 are respectively connected with the third linear sliding table 11 and the second sliding rod 12, the length direction of the bar-shaped scraping blocks 14 is perpendicular to the length direction of the third linear sliding table 11, the bottom of each bar-shaped scraping block 14 can be attached to the top of the upper partition plate 2, a plurality of sliding strips 16 are arranged on the vertical side wall of each bar-shaped scraping block 14, a plurality of sliding grooves 17 which are in sliding fit with the sliding strips 16 are formed in the inner side wall of the connecting frame 15, and the fact that the two bar-shaped scraping blocks 14 can vertically move up and down in the connecting frame 15 is guaranteed.

A rotatable rotating shaft 18 is arranged in the connecting frame 15, the axial direction of the rotating shaft 18 is parallel to the length direction of the strip-shaped scraping blocks 14, the rotating shaft 18 is positioned between the two strip-shaped scraping blocks 14, a notch 19 is formed in the middle of the connecting frame 15, a gear 39 is arranged in the notch 19 and fixedly sleeved on the rotating shaft 18 in the interior, vertical racks 20 are arranged on one sides of the two strip-shaped scraping blocks 14, which are close to each other, the gear 39 is meshed with the two racks 20 on the two sides respectively, a driving motor 21 is arranged at the top of the connecting frame 15, the driving motor 21 is positioned above one side end part of the rotating shaft 18, an output shaft of the driving motor 21 is in transmission connection with the rotating shaft 18 through a synchronous belt 22, the driving motor 21 drives the rotating shaft 18 to rotate, the rotating shaft 18 drives the gear 39 to rotate, the gear 39 rotates to enable the two bar-shaped scraping blocks 14 meshed with the gear 39 to move in the vertical direction, when the powder spreader 13 moves to the rightmost side through the third linear sliding table 11, the gear 39 rotates positively, the left bar-shaped scraping block 14 moves upwards, the right bar-shaped scraping block 14 moves downwards and is attached to the upper end face of the upper partition plate 2, the third linear sliding table 11 drives the powder spreader 13 to move leftwards, so that powder sent out from the feeding device is paved on the upper end face of the supporting plate 4, after the laser 10 finishes sintering printing of the layer, the supporting plate 4 descends for a small distance, the upper end face of the supporting plate 4 is still lower than the upper end face of the upper partition plate 2, smooth powder paving is ensured, the gear 39 rotates reversely, the left bar-shaped scraping block 14 moves downwards until being attached to the upper end face of the upper partition plate 2, and the right bar-shaped scraping block 14 moves upwards, the strip-shaped scraping block 14 is driven by the third linear sliding table 11 to spread the powder sent out by the feeding device on the upper end face of the bearing plate 4, so that the powder can be spread at the two ends of the printing area in a reciprocating manner.

Every the both ends of piece 14 are scraped to the bar all are provided with a vertical chamber 23 that holds, and every holds and all is provided with a spring 24 and a gyro wheel 25 in the chamber 23, and the both ends of spring 24 are contradicted with the top that holds chamber 23 and gyro wheel 25 respectively, and the bottom of every gyro wheel 25 all can stretch out and hold chamber 23 and laminate with the top of last baffle 2, and gyro wheel 25 makes the bar scrape piece 14 and can smoothly remove on last baffle 2.

The feeding device comprises four powder boxes 26 vertically arranged on two sides of a supporting plate 4, the four powder boxes 26 are located on two sides of the supporting plate 4 in pairs, each powder box 26 is of an upper opening and lower opening structure, a vertical U-shaped push plate 27 is arranged at the bottom of each two powder boxes 26 on each side, a lifting device 28 is connected to the bottom of each U-shaped push plate 27, the lifting device 28 is fixedly arranged at the top of a lower partition plate 3, the top of each U-shaped push plate 27 can extend into the corresponding powder box 26 from bottom to top, the side wall of the upper half of each U-shaped push plate 27 is completely attached to the inner wall of the corresponding powder box 26, and before the powder spreading operation of the strip-shaped scraping block 14, the lifting device 28 lifts the U-shaped push plate 27 for a distance, so that printing powder in the two powder boxes 26 above is pushed out from the opening above the U-shaped push plate 27, and the printing powder is spread on the upper end face of the supporting plate 4 in the horizontal movement process of the strip-shaped scraping block 14.

The top of every powder box 26 all flushes with the up end of last baffle 2, and the top of every powder box 26 is the hopper-shaped structure, and the travel distance of third sharp slip table 11 is greater than the distance between two powder boxes 26 in the outside, and the length of piece 14 is greater than the width of carrier board 4 is scraped to the bar, and two powder boxes 26 have been set up on each side and have guaranteed the stability of play powder and the sufficiency of play powder volume.

The lifting device 5 and the lifting device 28 are identical in structure and comprise a mounting shell 29, a screw rod 30, a worm 31, a turbine 32 and a rotating motor 38, the screw rod 30 vertically penetrates through the mounting shell 29, the worm 31 horizontally penetrates through the mounting shell 29, one end of the worm 31 is fixedly connected with the rotating motor 38, the turbine 32 is sleeved on the screw rod 30, internal threads matched with the screw rod 30 are arranged on the inner side wall of the turbine 32, the worm 31 is meshed with the turbine 32, an extending shaft sleeve 33 is arranged at the upper end and the lower end of the turbine 32, a bearing is sleeved on each extending shaft sleeve 33, an inner ring of the bearing is fixedly sleeved on the extending shaft sleeve 33, an outer ring of the bearing is fixedly connected with the inner wall of the mounting shell 29, the bottoms of all the screw rods 30 penetrate through the lower partition plate 3 and extend downwards, smooth rotation of the turbine 32 is guaranteed by the bearing, the rotating motor 38 drives the worm 31 to rotate, the worm 31 drives the worm 32 meshed with the worm, and the turbine 32 rotates through the internal threads on the inner wall and the external threads of the screw rod 30, so that the screw rod 30 can move upwards or downwards along with the rotation of the turbine 32.

The center of the upper partition plate 2 is provided with a lifting slide way 34 which has the same shape as the supporting plate 4, the bottom of the lifting slide way 34 extends vertically downwards, the height of the lifting slide way 34 is larger than the thickness of the supporting plate 4, and the lifting slide way 34 ensures that the paved powder cannot fall off and loosen in the process of each descending of the supporting plate 4.

One side of the casing 1 is hinged with an upper door plate 35 and a lower door plate 35, and both sides of the upper part of each door plate 35 and the casing 1 are respectively provided with a transparent observation window 36, so that the printing state of the article can be observed at any time.

A filling hopper 37 is placed at the bottom of the inner side of the casing 1, and a sufficient amount of printing powder is added into the four powder boxes 26 through the filling hopper 37 before printing.

The laser 10 is an infrared laser 10, and the powder below is sintered and printed by using the infrared laser 10 as a heat source.

The control box 6 is provided with a display screen and control keys, the control box 6 controls the printing process of the whole equipment, the printing process comprises working states of the driving motor 21 and the rotating motor 38, and the display screen displays the printing progress in real time.

Working principle: when in use, a sufficient amount of printing powder is added into the four powder boxes 26 through the filler hopper 37, the door plate 35 is closed, the equipment is operated through the control keys, the lifting device 28 lifts the U-shaped push plate 27 for a certain distance, the U-shaped push plate 27 pushes the printing powder in the two powder boxes 26 above out of the opening above, the printing powder is paved on the upper end face of the supporting plate 4 in the horizontal movement process of the strip-shaped scraping block 14, then the driving motor 21 drives the rotating shaft 18 to rotate, the rotating shaft 18 drives the gear 39 to rotate, the gear 39 rotates to enable the two meshed strip-shaped scraping blocks 14 to move in the vertical direction, when the powder spreader 13 moves to the rightmost side through the third linear sliding table 11, the gear 39 rotates positively, the left strip-shaped scraping block 14 moves upwards, the right bar-shaped scraping block 14 moves downwards and is attached to the upper end face of the upper partition plate 2, at the moment, the third linear sliding table 11 drives the powder spreader 13 to move leftwards, so that powder sent out from the feeding device is spread on the upper end face of the supporting plate 4, after the laser 10 finishes sintering printing of the layer, the supporting plate 4 descends for a small distance, the upper end face of the supporting plate 4 is still lower than the upper end face of the upper partition plate 2, smooth powder spreading is ensured, at the moment, the gear 39 is reversed, the left bar-shaped scraping block 14 moves downwards until being attached to the upper end face of the upper partition plate 2, the right bar-shaped scraping block 14 moves upwards, and the third linear sliding table 11 drives the bar-shaped scraping block 14 to spread the powder sent out from the feeding device on the upper end face of the supporting plate 4, so that both ends of a printing area can be spread.

The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the technical scope of the present invention, so any minor modifications, equivalent changes and modifications made to the above embodiments according to the technical principles of the present invention are still within the scope of the technical solutions of the present invention.

Claims

1. The utility model provides a two-way shop's powder device of powder printing which characterized in that: the powder feeder comprises a feeding device and a powder spreading device which are arranged inside a printer shell (1), wherein the shell (1) is vertically arranged, the inner space of the shell is divided into three parts by an upper partition plate (2) and a lower partition plate (3), the upper partition plate (2) and the lower partition plate (3) are horizontally arranged, the upper partition plate (2) and the lower partition plate (3) are arranged at intervals in the vertical direction, the powder spreading device and the feeding device are respectively positioned above and below the upper partition plate (2), a supporting plate (4) capable of moving up and down is arranged at the center of the upper partition plate (2), the feeding device is communicated with the upper part of the upper partition plate (2), the upper end surfaces of the feeding device and the upper partition plate (2) are flush, the bottom of the powder spreading device is attached to the upper end surface of the upper partition plate (2), the powder spreading device can horizontally move at the top of the upper partition plate (2), the feeding device is positioned at the edge of the supporting plate (4), one end of the powder spreading device comprises a third linear sliding table (11), a second linear sliding table (12) and a powder spreader (13), one end of the powder spreader (13) is fixedly connected with the third linear sliding table (11), the other end of the third linear sliding table (11) is fixedly connected with the other end of the third linear sliding table (11) and is provided with the second sliding table (26) and is fixedly sleeved on the two sides of the fourth sliding table (26) and comprises a fourth sliding rod (26) and is arranged on the two side of the vertical sliding rod (26;

the powder spreader (13) comprises two strip-shaped scraping blocks (14) and a connecting frame, the two strip-shaped scraping blocks (14) and the connecting frame are horizontally arranged, the two strip-shaped scraping blocks (14) can vertically move and are arranged on the inner side of the connecting frame, two ends of the connecting frame are respectively connected with the third linear sliding table (11) and the second sliding bar (12), the length direction of each strip-shaped scraping block (14) is perpendicular to the length direction of the third linear sliding table (11), the bottom of each strip-shaped scraping block (14) can be attached to the top of the upper partition plate (2), a plurality of sliding bars (16) are arranged on the vertical side wall of each strip-shaped scraping block (14), a plurality of sliding grooves (17) which are in sliding fit with the sliding bars (16) are arranged on the inner side wall of the connecting frame, a rotatable rotating shaft (18) is arranged in the connecting frame, the axial direction of the rotating shaft (18) is parallel to the length direction of the strip-shaped scraping blocks (14), the rotating shaft (18) is positioned in the middle of the two scraping blocks (14), one gear (19) is arranged in the middle of the connecting frame, two gears (39) are arranged on two sides of the two side racks (20) and are meshed with one side of the two gears (20) and are arranged on the two sides of the two gears (39) respectively, the top of the connecting frame is provided with a driving motor (21), the driving motor (21) is positioned above one side end part of the rotating shaft (18), an output shaft of the driving motor (21) is in transmission connection with the rotating shaft (18) through a synchronous belt (22), the driving motor (21) drives the rotating shaft (18) to rotate, the rotating shaft (18) drives a gear (39) to rotate, the gear (39) rotates so that two meshed strip-shaped scraping blocks (14) move in the vertical direction, when the powder spreader (13) moves to the rightmost side through a third linear sliding table (11), at the moment, the gear (39) positively rotates, the left strip-shaped scraping block (14) moves upwards, the right strip-shaped scraping block (14) downwards moves and is attached to the upper end surface of the upper supporting plate (2), at the moment, the third linear sliding table (11) drives the powder spreader (13) to move leftwards, so that powder sent out from the feeding device is paved on the upper end surface of the supporting plate (4), after the laser (10) finishes printing of the layer, the lower section of the supporting plate (4) is lowered, the upper end surface of the lower section of the supporting plate (4) is enabled to be lower than the upper end surface of the supporting plate (14) to be attached to the upper end surface of the upper supporting plate (2) smoothly, and the upper end surface of the supporting plate (14) is still attached to the upper end surface of the upper plate (2) is guaranteed to be attached to the upper end surface of the upper plate (2 smoothly, the strip scraping block (14) is driven by the third linear sliding table (11) to spread the powder sent by the feeding device on the upper end surface of the supporting plate (4), so that the powder can be spread at the two ends of the printing area in a reciprocating manner; two ends of each bar-shaped scraping block (14) are respectively provided with a vertical accommodating cavity (23), each accommodating cavity (23) is internally provided with a spring (24) and a roller (25), two ends of the spring (24) respectively abut against the top of each accommodating cavity (23) and the top of each roller (25), and the bottom of each roller (25) can extend out of each accommodating cavity (23) and be attached to the top of the upper partition plate (2);

the four powder boxes (26) are located on two sides of the supporting plate (4) in pairs, each powder box (26) is of an upper opening structure and a lower opening structure, the bottoms of the two powder boxes (26) on each side are provided with a vertical U-shaped push plate (27), the bottom of each U-shaped push plate (27) is connected with a lifting device (28), the lifting devices (28) are fixedly arranged at the top of the lower partition plate (3), the top of each U-shaped push plate (27) can extend into the corresponding powder box (26) from bottom to top, and the side wall of the upper half of each U-shaped push plate (27) is completely attached to the inner wall of the corresponding powder box (26);

lifting device (28) are including installing shell (29), screw rod (30), worm (31), turbine (32) and rotating electrical machines (38), screw rod (30) are vertical to run through installing shell (29), worm (31) level runs through installing shell (29) and one end and rotating electrical machines (38) fixed connection of worm (31), turbine (32) cover is established on screw rod (30) and be provided with on the inside wall of turbine (32) with screw rod (30) complex internal thread, worm (31) and turbine (32) meshing, the upper and lower extreme of turbine (32) all is provided with one and extends axle sleeve (33), all overlap on every extension axle sleeve (33) and be equipped with a bearing, the inner circle fixed sleeve of bearing is established on extension axle sleeve (33), the outer lane of bearing and the inner wall fixed connection of installing shell (29), all the bottom of screw rod (30) all passes under baffle (3) and extends downwards.