CN114714617B - Powder supply and paving integrated device for improving workpiece density and working method - Google Patents

Abstract

The invention provides a powder supply and paving integrated device for improving workpiece density and a working method thereof, comprising the following steps: the powder feeding screening channel box assembly, the powder separator moving mechanism assembly, the powder falling device assembly, the powder paving plate and the central controller; the powder separator moving mechanism is provided with a screening plate; the periphery of the lower powder screening channel box assembly is provided with a plurality of powder separator moving mechanisms from top to bottom, and a plurality of screening plates are allowed to move into the lower powder screening channel box assembly; the filtering apertures of the screening plates are gradually reduced from top to bottom, and powder is gradually screened by the screening plates according to the filtering apertures after being placed into a lower powder screening channel box assembly channel; the screening plates allow movement to and one-to-one correspondence with the powder dropping devices, and the screening plates allow placement of the powder into the corresponding powder dropping devices. The device can separate the powder with different particle sizes in the powder spreading process, and then form a powder layer with gradually reduced particle sizes from bottom to top.

Description

Powder supply and paving integrated device for improving workpiece density and working method

Technical Field

The invention relates to the field of additive manufacturing, in particular to a powder supply and laying integrated device for improving workpiece compactness and a working method.

Background

In the current additive manufacturing field, powder has particle size distribution in a certain section after production is completed, the existing powder paving mode is used for simply paving powder into a forming area, powder particles with various particle sizes of a formed powder layer are arranged in a disordered manner, larger gaps exist among the powder particles with different particle sizes in the powder layer, and thus the density of a formed workpiece is low after laser scanning, so that the mechanical property of the formed workpiece is poor, and the problem needs to be solved urgently.

Patent document CN111267345a relates to a powder spreading type 3D printing device, which mainly solves the problems of large additional vibration, low printing efficiency and complex workpiece taking of the existing powder bonding 3D printer. The powder spreading type 3D printing device comprises a fixed bracket, a forming cylinder, a lifting assembly arranged below the forming cylinder, a powder feeding mechanism and a printing head, wherein the powder feeding mechanism and the printing head are fixed above the forming cylinder; the shaping jar outside is provided with two parallel sliding guide along the direction of printing, and the shaping jar is installed on the fixed bolster, and send whitewashed mechanism includes powder fill, pivot, sieve motor, back shaft and hold-in range, and the pivot is fixed in the powder fill perpendicularly to the direction of printing, and two sets of spiral grooves opposite in direction of rotating have been seted up on the surface, and the powder fill bottom is equipped with movable sieve and fixed sieve that arrange from top to bottom, and the powder fill bottom is equipped with the scraper, and the outside is fixed in on the installing support, and the print head is fixed in on the installing support adjacent with sending whitewashed mechanism, and iron plate has been placed to shaping jar bottom, and lifting unit top is equipped with the electromagnetism piece of inhaling with iron plate contact.

Patent document CN105291441A moves jar shop powder formula 3D printer, belongs to the additive manufacturing field; the printer powder box is fixed, and the lower part of the powder box is provided with a powder spreading scraper, so that the powder supply and spreading device is of an integrated structure; when the molding cylinder retreats and the molding cavity is arranged below the opening of the powder box A, as the piston descends and the molding cylinder has a gap, the powder to be used flows into the molding cylinder from the abdominal cavity of the powder box A, which is equivalent to powder supply; when the forming cylinder advances, the forming cylinder takes away the standby powder flowing into the forming cylinder, and as the scraper is arranged below the powder box A, the scraper and the forming cylinder form relative motion, so that the standby powder on the forming cylinder is scraped to be equal to powder paving; after the powder spreading is completed, the sintering (or curing) device starts to work, and the powder to be used is sintered (or cured) in the area needing sintering (or curing); after sintering (or curing) is finished, namely the printer finishes one cycle, the forming cylinder retreats again, the cycle starts again, and the printing process of the 3D printer is repeated for a plurality of times.

The above-mentioned prior patent fails to solve the problem of low density of molded workpieces in the field of additive manufacturing.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a powder supply and paving integrated device for improving the compactness of a workpiece and a working method.

According to the invention, the powder supplying and paving integrated device for improving the compactness of the workpiece comprises the following components: the powder feeding screening channel box assembly, the powder separator moving mechanism assembly, the powder falling device assembly, the powder paving plate and the central controller;

the powder separator motion mechanism assembly comprises a plurality of powder separator motion mechanisms, wherein the powder separator motion mechanisms are provided with screening plates;

a plurality of powder separator moving mechanisms are arranged on the periphery of the lower powder screening channel box assembly from top to bottom, and a plurality of screening plates are allowed to move into the lower powder screening channel box assembly;

the filtering pore diameters of the screening plates are gradually reduced from top to bottom, and powder is gradually screened by the screening plates according to the filtering pore diameters after being placed into the lower powder screening channel box assembly channel;

the powder falling device assembly is arranged above the powder paving plate and comprises a plurality of powder falling devices;

the screening plates allow the powder to be moved to the powder falling devices and are in one-to-one correspondence with the powder falling devices, and the screening plates allow the powder to be placed into the powder falling devices;

the central controller is electrically connected with the powder discharging screening channel box assembly, the powder separator moving mechanism assembly, the powder falling device assembly and the powder paving plate.

Preferably, the powder separator movement mechanism comprises: the device comprises a linear guide rail, a linear guide rail sliding accessory, a box body, a rotating shaft, a speed reducer, a first motor, a motor bracket, a toothed belt, a gear and a second motor;

the box body is provided with the linear guide rail sliding accessory and the rack belt, and one end of the linear guide rail is fixedly connected with the powder discharging screening channel box assembly and is in sliding fit connection with the linear guide rail sliding accessory;

the second motor is fixedly connected with the powder discharging screening channel box assembly, the gear is arranged at the output end of the second motor, the gear is meshed with the rack belt, and the second motor is meshed with the rack belt through the gear to drive the box body to move;

the first motor is fixedly arranged in the box body through the motor bracket, the output end of the first motor is provided with the speed reducer, and the speed reducer is connected with the screening plate through the rotating shaft;

the central controller is electrically connected with and controls the first motor to drive the screening plate to overturn, and the central controller controls the second motor to drive the gear to rotate and drive the screening plate to horizontally move relative to the powder discharging screening channel box assembly.

Preferably, the powder down screening channel box assembly comprises: ball valve, roof, main box board, baffle and side board;

the side of the main box body plate is provided with the side plate, the top of the main box body plate is provided with the top plate, and the main box body plate, the side plate and the top plate are surrounded to form a cavity;

the side surface of the main box body plate is provided with a plurality of rectangular through holes, the rectangular through holes are communicated with the cavity, a plurality of partition plates are arranged in the cavity, and the screening plate is allowed to move into the cavity through the rectangular through holes;

the partition board is arranged between the adjacent powder separator moving mechanisms, and the central controller is electrically connected with and controls the partition board to turn over in the cavity;

the ball valve is installed on the top plate, the powder monitoring module is installed in the ball valve, the powder is allowed to be placed in the cavity by opening the ball valve, and the central controller is electrically connected with the ball valve.

Preferably, the powder separator movement mechanism assembly comprises: a first powder separator motion mechanism, a second powder separator motion mechanism, a third powder separator motion mechanism, and a fourth powder separator motion mechanism;

the first powder separator moving mechanism, the second powder separator moving mechanism, the third powder separator moving mechanism and the fourth powder separator moving mechanism are arranged on the side surface of the lower powder screening channel box assembly from top to bottom;

The powder is screened into second-particle-size powder particles, first-particle-size powder particles, third-particle-size powder particles and fourth-particle-size powder particles through the first-powder-separator moving mechanism, the second-powder-separator moving mechanism, the third-powder-separator moving mechanism and the fourth-powder-separator moving mechanism respectively;

the first particle size powder particles, the second particle size powder particles, the third particle size powder particles, and the fourth particle size powder particles increase in size in order.

Preferably, the powder falling device comprises: a powder falling device top pipeline, an electrified magnetic pole device, a powder falling device bottom pipeline and a bottom partition plate;

the powder falling device top pipeline is connected with the powder falling device bottom pipeline, and the electrified magnetic pole device is arranged between the powder falling device top pipeline and the powder falling device bottom pipeline;

one end of the bottom pipeline of the powder falling device, which is opposite to the top pipeline of the powder falling device, is provided with the bottom partition plate, and the bottom partition plate allows the bottom pipeline of the powder falling device to be separated;

the powder is allowed to be transferred to above the top pipeline of the powder falling device through the screening plate, and the powder is poured into the top pipeline of the powder falling device through the screening plate through the overturning driven by the first motor.

Preferably, the powder falling device assembly comprises a first powder falling device, a second powder falling device, a third powder falling device and a fourth powder falling device;

the fourth-particle-size powder particles are conveyed through the fourth powder separator moving mechanism and are poured into the fourth powder falling device;

the third-particle-size powder particles are conveyed through the third powder separator moving mechanism and are poured into the third powder falling device;

the second-particle-size powder particles are conveyed through the first powder separator moving mechanism and are poured into the first powder falling device;

the first-size powder particles are conveyed by the second powder separator moving mechanism and are poured into the second powder falling device.

Preferably, a magnetic plate is correspondingly arranged above the powder falling device;

the central controller is electrically connected with and controls the magnetic pole plate and the electrified magnetic pole device to be electrified, when the magnetic pole plate and the electrified magnetic pole device are electrified, a magnetic field is formed between the magnetic pole plate and the electrified magnetic pole device, and the powder is attached to a top pipeline of the powder falling device from the sieving plate through the magnetic field;

When the magnetic pole plate and the electrified magnetic pole device are powered off, the powder falls to the bottom of the powder falling device;

the central controller is electrically connected with and controls the bottom partition board to be pulled away, and when the bottom partition board is pulled away, the powder falls down and is paved on the powder paving board.

Preferably, the magnetic pole plate includes: the first magnetic plate, the second magnetic plate, the third magnetic plate and the fourth magnetic plate;

the first magnetic plate is arranged above the first powder falling device, the second magnetic plate is arranged above the second powder falling device, the third magnetic plate is arranged above the third powder falling device, and the fourth magnetic plate is arranged above the fourth powder falling device.

Preferably, a forming substrate is arranged on the powder spreading plate, two sides of the forming substrate are respectively provided with a first powder spreading plate powder discharging opening and a second powder spreading plate powder discharging opening, and the central controller is electrically connected with and controls the opening and closing of the first powder spreading plate powder discharging opening and the second powder spreading plate powder discharging opening;

one end of the powder spreading plate is provided with a scraper, the bottom of the powder spreading plate is provided with a molding cylinder lifting mechanism, the central controller is electrically connected with and controls the scraper to move along the extending direction of the powder spreading plate, and the central controller is electrically connected with the molding cylinder lifting mechanism;

The lower powder screening channel box assembly is provided with a moving mechanism, and the central controller is electrically connected with and controls the moving mechanism to drive the lower powder screening channel box assembly to move along the direction vertical to the powder paving plate in the horizontal plane.

Preferably, the working method of the powder supply and paving integrated device for improving the compactness of the workpiece comprises the following steps:

step S1, the central controller controls four screening plates to move into the main box body plate, and the central controller controls the partition plates to be in a closed state;

step S2, the central controller controls the ball valve to be opened, the powder enters the cavity through the ball valve, the powder particles with the fourth particle size stay on the uppermost screening plate, and the rest of the powder falls on a partition plate between the third powder separator moving mechanism and the fourth powder separator moving mechanism;

step S3, the central controller controls the fourth powder separator moving mechanism to move to the position right above the fourth powder falling device through a second motor of the fourth powder separator moving mechanism, the central controller controls a screening plate of the fourth powder separator moving mechanism to turn 180 degrees through a first motor of the fourth powder separator moving mechanism, most of the fourth particle size powder particles fall on a bottom partition plate of the fourth powder falling device, and as a certain amount of the fourth particle size powder particles still adhere to the screening plate of the fourth powder separator moving mechanism, the central controller energizes the fourth magnetic pole plate and an energizing magnetic pole device of the fourth powder falling device, and the formed magnetic fields act together to enable the fourth particle size powder particles adhered to the screening plate of the fourth powder separator moving mechanism to fall on the side wall of a powder falling device top pipeline of the fourth powder falling device until the residual fourth particle size powder particles completely move to the side wall of the powder falling device top pipeline of the fourth powder falling device, and the fourth particle size particles completely move to the fourth powder falling device bottom pipeline side wall until the fourth particle size particles completely fall on the fourth powder falling device bottom partition plate;

Step S4, the central controller controls to open a partition plate between the third powder separator moving mechanism and the fourth powder separator moving mechanism, the third particle size powder particles fall and stay on a screening plate of the third powder separator moving mechanism, the rest of powder fall on the partition plate between the third powder separator moving mechanism and the first powder separator moving mechanism, and the third powder separator moving mechanism, the first powder separator moving mechanism and the second powder separator moving mechanism repeat the operation method of the fourth powder separator moving mechanism in step S3 in sequence until the fourth particle size powder particles, the third particle size powder particles, the second particle size powder particles and the first particle size powder particles fall on bottom partition plates of the fourth powder falling device, the third powder falling device, the first powder falling device and the second powder falling device respectively;

step S5, the central controller controls to open a bottom partition plate of the fourth powder falling device, fourth powder particles fall onto the powder spreading plate, the central controller controls the second powder spreading plate to close a powder outlet and the first powder spreading plate to open a powder outlet, the central controller controls the scraper to move, the scraper pushes the fourth powder particles onto the forming substrate, redundant fourth powder particles enter a powder recovery system through the first powder spreading plate outlet, and the scraper moves to an initial position at the left end of the powder spreading plate again;

Step S6, the central controller controls to open a bottom partition plate of the third powder falling device, third-particle-size powder particles fall onto the powder spreading plate, the central controller controls the scraper to move, the scraper pushes the third-particle-size powder particles onto the forming substrate, the redundant third-particle-size powder particles enter a powder recovery system through a powder outlet of the first powder spreading plate, the scraper moves to the rightmost end of the powder spreading plate, and the third-particle-size powder particle layer is spread onto fourth-particle-size powder particles;

step S7, the central controller controls to close the powder outlet of the first powder paving plate, simultaneously opens the powder outlet of the second powder paving plate and the bottom partition plate of the first powder falling device, the second particle size powder particles fall onto the powder paving plate, the central controller controls the scraper to start moving leftwards, the scraper pushes the second particle size powder particles onto the forming substrate, the redundant second particle size powder particles enter a powder recovery system through the powder outlet of the second powder paving plate, the second particle size powder particle layers are paved on the third particle size powder particle layers, and the scraper moves to the rightmost end of the powder paving plate again;

Step S8, the central controller controls to open a bottom baffle plate of a second powder falling device, the first-particle-size powder particles fall onto the powder spreading plate, the central controller controls the scraper to move leftwards, the scraper pushes the first-particle-size powder particles onto the forming substrate, the redundant first-particle-size powder particles enter a powder recovery system through a powder outlet of the second powder spreading plate, a first-particle-size powder particle layer is spread onto the second-particle-size powder particles, and the scraper moves to the initial position at the left end of the powder spreading plate again;

after the powder layer is paved, the powder layer is divided into the first particle size powder particle, the second particle size powder particle, the third particle size powder particle and the fourth particle size powder particle from top to bottom, the lower part of the powder layer is the fourth particle size powder particle, the middle part of the fourth particle size powder particle is mixed with the first particle size powder particle, the second particle size powder particle and the third particle size powder particle, the middle part of the third particle size powder particle is mixed with the first particle size powder particle and the second particle size powder particle, the middle part of the second particle size powder particle is mixed with the first particle size powder particle, and the upper part of the powder layer is the first particle size powder particle;

And S9, after the central controller controls the powder discharging screening channel box assembly to be removed, starting a single-layer laser scanning process, and repeating the operation processes from the step S1 to the step S8 after the single-layer laser scanning is completed.

Preferably, the motion mechanism is provided with a synchronous belt, a synchronous wheel, a ball screw and a screw nut.

Preferably, the heights of the second magnetic plate, the first magnetic plate, the third magnetic plate and the fourth magnetic plate are sequentially increased from the powder spreading plate.

Compared with the prior art, the invention has the following beneficial effects:

the invention provides a powder supply and laying integrated device capable of improving the density of a workpiece in the field of additive manufacturing and a working method thereof, wherein the device can separate powder with different particle sizes in powder in the powder laying process, then a powder layer with gradually reduced particle sizes from bottom to top is formed, the space in the powder layer is basically filled completely, and the density and mechanical property of a formed workpiece are improved to a great extent after the laser scanning process.

Drawings

Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:

FIG. 1 is a schematic diagram of a powder feeding and laying integrated device;

FIG. 2 is a schematic right side view of a lower powder screening channel box assembly;

FIG. 3 is a schematic left-hand view of a breading screening channel box assembly;

FIG. 4 is a schematic diagram of a front view of the powder separator;

FIG. 5 is a schematic view of a powder separator from the back side;

FIG. 6 is a schematic view of a powder dropping device;

FIG. 7 is a schematic illustration of a magnetic field formed between an energized pole set and a pole plate;

FIG. 8 is a schematic diagram of a lay-up structure of a single powder layer;

fig. 9 is a schematic diagram of different states of the powder spreading process.

The figure shows:

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present invention.

Example 1

As shown in fig. 1, a powder supplying and spreading integrated device for improving workpiece compactness comprises: a lower powder screening channel box assembly 1, a powder separator motion mechanism assembly, a powder falling device assembly, a powder paving plate 51 and a central controller; the powder separator motion mechanism assembly includes a plurality of powder separator motion mechanisms, the powder separator motion mechanisms mounting the screening plates 204; the circumference side of the lower powder screening channel box assembly 1 is provided with a plurality of powder separator moving mechanisms from top to bottom, and a plurality of screening plates 204 are allowed to move into the lower powder screening channel box assembly 1; the filtering pore diameters of the screening plates 204 are gradually reduced from top to bottom, and powder is gradually screened by the screening plates 204 according to the filtering pore diameters after being placed in a channel of the lower powder screening channel box assembly 1; a powder falling device assembly is disposed above the powder spreading plate 51, the powder falling device assembly including a plurality of powder falling devices; the sieving plate 204 allows moving to the powder falling device and corresponds to the powder falling device one by one, and the sieving plate 204 allows placing the powder into the corresponding powder falling device; the central controller is electrically connected to the lower powder screening chute assembly 1, the powder separator movement mechanism assembly, the powder fall device assembly and the powder spreading plate 51. The powder separator motion mechanism assembly includes: a first powder separator movement mechanism 21, a second powder separator movement mechanism 22, a third powder separator movement mechanism 23, and a fourth powder separator movement mechanism 24; the first powder separator moving mechanism 21, the second powder separator moving mechanism 22, the third powder separator moving mechanism 23 and the fourth powder separator moving mechanism 24 are arranged on the side surface of the lower powder screening channel box assembly 1 from top to bottom; the powder is sieved into second, first, third and fourth particle size powder particles by the first, second, third and fourth powder separator movement mechanisms 21, 22, 23 and 24, respectively; the first particle size powder particles, the second particle size powder particles, the third particle size powder particles, and the fourth particle size powder particles increase in particle size in order. The powder falling device assembly includes a first powder falling device 41, a second powder falling device 42, a third powder falling device 43, and a fourth powder falling device 44; the fourth size powder particles are transported by the fourth powder separator motion mechanism 24 and poured into the fourth powder falling device 44; the third-size powder particles are conveyed by the third powder separator movement mechanism 23 and inverted into the third powder falling device 43; the second-size powder particles are conveyed by the first powder separator movement mechanism 21 and inverted into the first powder falling device 41; the first size powder particles are transported by the second powder separator motion mechanism 22 and inverted into the second powder falling device 42. The magnetic pole plate includes: a first magnetic plate 31, a second magnetic plate 32, a third magnetic plate 33, and a fourth magnetic plate 34; the first magnetic plate 31 is positioned above the first powder dropping device 41, the second magnetic plate 32 is positioned above the second powder dropping device 42, the third magnetic plate 33 is positioned above the third powder dropping device 43, and the fourth magnetic plate 34 is positioned above the fourth powder dropping device 44. A molding substrate 53 is arranged on the powder spreading plate 51, a first powder spreading plate lower powder opening 52 and a second powder spreading plate lower powder opening 54 are respectively arranged on two sides of the molding substrate 53, and a central controller is electrically connected and controls the opening and closing of the first powder spreading plate lower powder opening 52 and the second powder spreading plate lower powder opening 54; one end of the powder spreading plate 51 is provided with a scraper 55, the bottom of the powder spreading plate 51 is provided with a molding cylinder lifting mechanism 6, the central controller is electrically connected with the scraper 55 and controls the scraper 55 to move along the extending direction of the powder spreading plate 51, and the central controller is electrically connected with the molding cylinder lifting mechanism 6; the lower powder screening channel box assembly 1 is provided with a moving mechanism, and the central controller is electrically connected with and controls the moving mechanism to drive the lower powder screening channel box assembly 1 to move along the direction vertical to the powder paving plate 51 in the horizontal plane.

As shown in fig. 4 and 5, the powder separator movement mechanism includes: linear guide 201, linear guide sliding accessory 202, box 203, rotating shaft 205, speed reducer 206, first motor 207, motor bracket 208, rack belt 209, gear 210 and second motor 211; the box body 203 is provided with a linear guide rail sliding accessory 202 and a rack belt 209, and one end of the linear guide rail 201 is fixedly connected with the powder discharging screening channel box assembly 1 and is in sliding fit connection with the linear guide rail sliding accessory 202; the second motor 211 is fixedly connected with the powder discharging screening channel box assembly 1, a gear 210 is arranged at the output end of the second motor 211, the gear 210 is meshed with the rack belt 209, and the second motor 211 is meshed with the rack belt 209 through the gear 210 to drive the box 203 to move; the first motor 207 is fixedly arranged in the box 203 through a motor bracket 208, a speed reducer 206 is arranged at the output end of the first motor 207, and the speed reducer 206 is connected with the screening plate 204 through a rotating shaft 205; the central controller is electrically connected with and controls the first motor 207 to drive the screening plate 204 to overturn, and the central controller controls the second motor 211 to drive the gear 210 to rotate and drive the screening plate 204 to horizontally move relative to the powder discharging screening channel box assembly 1.

As shown in fig. 2 and 3, the breading screening channel box assembly 1 comprises: ball valve 11, top plate 12, main box plate 13, partition plate and side plate 14; a side plate 14 is arranged on the side surface of the main box plate 13, a top plate 12 is arranged on the top of the main box plate 13, and a cavity is formed by surrounding the main box plate 13, the side plate 14 and the top plate 12; the side surface of the main box body plate 13 is provided with a plurality of rectangular through holes, the rectangular through holes are communicated with a cavity, a plurality of partition plates are arranged in the cavity, and the screening plate 204 is allowed to move into the cavity through the rectangular through holes; a partition board is arranged between the adjacent powder separator moving mechanisms, and a central controller is electrically connected with and controls the partition board to turn over in the cavity; the ball valve 11 is installed on the top plate 12, the powder amount monitoring module is installed in the ball valve 11, powder is allowed to be placed into the cavity by opening the ball valve 11, and the central controller is electrically connected with the ball valve 11.

As shown in fig. 6, the powder falling device includes: a powder falling device top pipe 401, an energized pole device 402, a powder falling device bottom pipe 403, and a bottom partition 404; the powder falling device top pipeline 401 is connected with the powder falling device bottom pipeline 403, and an electrified magnetic pole device 402 is arranged between the powder falling device top pipeline 401 and the powder falling device bottom pipeline 403; the end of the powder falling device bottom pipe 403 facing away from the powder falling device top pipe 401 is provided with a bottom baffle 404, and the bottom baffle 404 allows the powder falling device bottom pipe 403 to be pulled away; the powder is allowed to pass over the powder fall device top duct 401 by the screen plate 204, which screen plate 204 is turned upside down into the powder fall device top duct 401 by the first motor 207 driving.

As shown in fig. 7, a magnetic plate is correspondingly arranged above the powder falling device, the central controller is electrically connected with and controls the magnetic plate and the electrified magnetic pole device 402 to be electrified, when the magnetic plate and the electrified magnetic pole device 402 are electrified, a magnetic field is formed between the magnetic plate and the electrified magnetic pole device 402, and powder is attached to the top pipeline 401 of the powder falling device from the sieving plate 204 through the magnetic field; when the magnetic pole plate and the electrified magnetic pole device 402 are powered off, the powder falls to the bottom of the powder falling device; the central controller is electrically connected to and controls the withdrawal of the bottom partition 404, when the bottom partition 404 is withdrawn, the powder falls down and spreads on the powder spreading plate 51.

As shown in fig. 8 and 9, a working method of the powder feeding and spreading integrated device for improving the compactness of a workpiece comprises the following steps: step S1, a central controller controls four screening plates 204 to move into a main box plate 13, and the central controller controls a partition plate to be in a closed state; step S2, the central controller controls the ball valve 11 to open, powder enters the cavity through the ball valve 11, the powder particles with the fourth particle size stay on the uppermost screening plate 204, and the rest of the powder falls on a partition plate between the third powder separator moving mechanism 23 and the fourth powder separator moving mechanism 24; step S3, the central controller controls the fourth powder separator moving mechanism 24 to move to the position right above the fourth powder falling device 44 through the second motor 211 of the fourth powder separator moving mechanism 24, the central controller controls the sieving plate 204 of the fourth powder separator moving mechanism 24 to turn 180 ° through the first motor 207 of the fourth powder separator moving mechanism 24, most of the fourth particle size powder particles fall on the bottom partition 404 of the fourth powder falling device 44, as a certain amount of the fourth particle size powder particles still adhere to the sieving plate 204 of the fourth powder separator moving mechanism 24, the central controller energizes the fourth magnetic pole plate 34 and the energizing magnetic pole device 402 of the fourth powder falling device 44, the formed magnetic field acts together to cause the fourth particle size powder particles adhered to the sieving plate 204 of the fourth powder separator moving mechanism 24 to fall on the top pipeline 401 side wall of the fourth powder falling device 44, and the remaining fourth particle size powder particles completely move to the top pipeline 401 side wall of the fourth powder falling device 44, and the fourth particle size particles completely fall on the bottom partition 404 of the fourth powder falling device 44 is disconnected; step S4, the central controller controls to open the partition plate between the third powder separator moving mechanism 23 and the fourth powder separator moving mechanism 24, the third particle size powder particles fall and stay on the sieving plate 204 of the third powder separator moving mechanism 23, the rest of the powder fall on the partition plate between the third powder separator moving mechanism 23 and the first powder separator moving mechanism 21, the third powder separator moving mechanism 23, the first powder separator moving mechanism 21 and the second powder separator moving mechanism 22 repeat the operation method of the fourth powder separator moving mechanism 24 in step S3 in order until the fourth particle size powder particles, the third particle size powder particles, the second particle size powder particles, the first particle size powder particles fall on the bottom partition plate 404 of the fourth powder falling device 44, the third powder falling device 43, the first powder falling device 41 and the second powder falling device 42, respectively; step S5, the central controller controls to open the bottom partition 404 of the fourth powder falling device 44, the fourth-grain-size powder particles fall onto the powder spreading plate 51, the central controller controls the second powder spreading plate powder discharging opening 54 to be closed and the first powder spreading plate powder discharging opening 52 to be opened, the central controller controls the scraper 55 to move, the scraper 55 pushes the fourth-grain-size powder particles onto the forming substrate 53, the redundant fourth-grain-size powder particles enter the powder recovery system through the first powder spreading plate powder discharging opening 52, and the scraper 55 moves to the initial position at the left end of the powder spreading plate 51 again; step S6, the central controller controls to open the bottom partition 404 of the third powder falling device 43, third-particle-size powder particles fall onto the powder spreading plate 51, the central controller controls the scraper 55 to move, the scraper 55 pushes the third-particle-size powder particles onto the forming substrate 53, redundant third-particle-size powder particles enter the powder recovery system through the first powder spreading plate lower powder opening 52, the scraper 55 moves to the rightmost end of the powder spreading plate 51, and the third-particle-size powder particles are spread on the fourth-particle-size powder particles; step S7, the central controller controls to close the first powder paving plate lower powder opening 52, simultaneously opens the second powder paving plate lower powder opening 54 and the bottom partition 404 of the first powder falling device 41, and enables the second-particle-size powder particles to fall onto the powder paving plate 51, the central controller controls the scraper 55 to start moving leftwards, the scraper 55 pushes the second-particle-size powder particles onto the forming substrate 53, the redundant second-particle-size powder particles enter the powder recovery system through the second powder paving plate lower powder opening 54, the second-particle-size powder particle layers are paved on the third-particle-size powder particle layers, and the scraper 55 moves to the rightmost end of the powder paving plate 51 again; step S8, the central controller controls to open a bottom partition plate of the second powder falling device 42, the first-particle-size powder particles fall onto the powder spreading plate 51, the central controller controls the scraper 55 to move leftwards, the scraper 55 pushes the first-particle-size powder particles onto the forming substrate 53, the redundant first-particle-size powder particles enter the powder recovery system through a powder outlet 54 of the second powder spreading plate, the first-particle-size powder particles are spread onto the second-particle-size powder particles, and the scraper 55 moves to the initial position at the left end of the powder spreading plate 51 again; after the powder layer is paved, the powder layer is divided into first particle size powder particles, second particle size powder particles, third particle size powder particles and fourth particle size powder particles from top to bottom, the lower part of the powder layer is the fourth particle size powder particles, the middle of the fourth particle size powder particles is mixed with the first particle size powder particles, the second particle size powder particles and the third particle size powder particles, the middle of the third particle size powder particles is mixed with the first particle size powder particles and the second particle size powder particles, the middle of the second particle size powder particles is mixed with the first particle size powder particles, and the upper part of the powder layer is the first particle size powder particles; and S9, after the central controller controls the powder discharging screening channel box assembly 1 to be moved away, starting a single-layer laser scanning process, and repeating the operation processes from the step S1 to the step S8 after the single-layer laser scanning is completed.

Example 2

Example 2 is a preferred example of example 1.

As shown in fig. 1, the present embodiment includes: the lower powder screening channel box assembly 1, the first powder separator movement mechanism 21, the second powder separator movement mechanism 22, the third powder separator movement mechanism 23, the fourth powder separator movement mechanism 24, the first magnetic plate 31, the second magnetic plate 32, the third magnetic plate 33, the fourth magnetic plate 34, the first powder falling device 41, the second powder falling device 42, the third powder falling device 43, the fourth powder falling device 44, the powder laying plate 51, the first powder laying plate lower powder opening 52, the forming substrate 53, the second powder laying plate lower powder opening 54, the forming cylinder lifting mechanism 6, the doctor blade 55 and the central controller.

The powder falling screening passage box assembly 1 includes: ball valve 11, roof 12, main box board 13 and curb plate 14, lower powder screening passageway case subassembly 1 left and right sides respectively open two rectangle through-holes, be equipped with three baffles in the lower powder screening passageway case subassembly 1, respectively between fourth powder separator motion 24 and third powder separator motion 23, third powder separator motion 23 and first powder separator motion 21 and second powder separator motion 22 and first powder separator motion 21, these three baffles can overturn in lower powder screening passageway case subassembly 1 inside, realize the separation function, lower powder screening passageway case subassembly 1 can pass through the motion mechanism back and forth along with shop's board 51 vertical direction in the horizontal direction, motion mechanism installation hold-in range, the synchronizing wheel, ball screw, screw nut etc.. After the powder layer is prepared, the powder discharging screening channel box assembly 1 can move backwards along the direction perpendicular to the powder spreading plate 51, then the optical path system starts the printing process, and the ball valve 11 is internally provided with a powder amount monitoring module, so that the amount of powder falling into the powder discharging screening channel box assembly 1 each time can be controlled.

The powder separator movement mechanism includes: linear guide 201, linear guide sliding accessory 202, box 203, screening plate 204, rotating shaft 205, speed reducer 206, first motor 207, motor bracket 208, rack belt 209, gear 210 and second motor 211; the first motor 207 is controlled by the central controller, the screening plates 204 can rotate 180 degrees through the speed reducer 206 and the rotating shaft 205, the gear 210 is driven by the second motor 211 to rotate through the gear strip 209, the linear guide rail 201 and the linear guide rail sliding accessory 202, the box 203 is driven to move left and right, accordingly, the screening plates 204 move left and right, the filter apertures of the four screening plates 201 are different, and the filter apertures are gradually reduced from top to bottom. The powder is divided into a first particle size powder particle, a second particle size powder particle, a third particle size powder particle and a fourth particle size powder particle according to the size of the particle sizes of the powder, when the powder falls down in the lower powder sieving passage box assembly 1, the fourth particle size powder particle stays on the sieving plate 204 in the fourth powder separator moving mechanism 24, the third particle size powder particle stays on the sieving plate 204 in the third powder separator moving mechanism 23, the second particle size powder particle stays on the sieving plate 204 in the first powder separator moving mechanism 21, and the first particle size powder particle stays on the sieving plate 204 in the second powder separator moving mechanism 22.

The powder falling device includes: the powder falling device top pipeline 401, the electrified magnetic pole device 402, the powder falling device bottom pipeline 403 and the bottom partition plate 404, wherein a magnetic field is formed between the electrified magnetic pole device 402 and the magnetic pole plate above the current powder falling device after being electrified, the magnetic field can apply a force to residual powder on the sieving plate 204 above the current powder falling device, the residual powder is enabled to move to the side wall of the powder falling device top pipeline 401, the residual powder can fall onto the bottom partition plate 404 after the electrified magnetic pole device 402 is closed, and the bottom partition plate 404 can be pulled.

The working method of the embodiment comprises the following steps:

firstly, a central controller gives an instruction to control the screening plates 204 in the four powder separator moving mechanisms to be inserted into the main box body plate 13 in the lower powder screening channel box assembly 1, and the screening plates for separating the powder particles with the fourth particle size, the screening plates for separating the powder particles with the third particle size, the screening plates for separating the powder particles with the second particle size and the screening plates for separating the powder particles with the first particle size are respectively arranged from top to bottom according to the difference of the filtering pore diameters of the screening plates 204, and the central controller gives an instruction to enable a partition plate between the fourth powder separator moving mechanism 24 and the third powder separator moving mechanism 23, a partition plate between the third powder separator moving mechanism 23 and the first powder separator moving mechanism 21 and a partition plate between the first powder separator moving mechanism 21 and the second powder separator moving mechanism 22 to be in a closed state;

Then the central controller gives an instruction, before the ball valve 11 at the upper part of the powder discharging screening channel box assembly 1 is opened, powder with single-layer powder quantity enters the powder discharging screening channel box assembly 1 through the ball valve 11, and powder particles with fourth particle size in the powder firstly stay on the screening plate 204 of the fourth powder separator moving mechanism 24, and the rest of the powder falls on a partition plate between the fourth powder separator moving mechanism 24 and the third powder separator moving mechanism 23;

then the central controller sends out an instruction to control the second motor 211 in the fourth powder separator moving mechanism 24 to drive the gear 210 to rotate, so as to drive the whole box 203 to move leftwards, thus the sieving plate 204 of the fourth powder separator moving mechanism 24 can move to the position right above the fourth powder falling device 44, then the central controller sends out an instruction to control the first motor 207 in the fourth powder separator moving mechanism 24 to enable the sieving plate 204 to turn over 180 degrees, most of the fourth particle size powder particles fall on the bottom partition 404 of the fourth powder falling device 44, and because a certain amount of the fourth particle size powder particles still adhere on the sieving plate 204, the central controller electrifies the fourth magnetic pole plate 34 and the electrifies magnetic pole device 402 in the fourth powder falling device 44, the formed magnetic field jointly acts to enable the fourth particle size powder particles adhered on the sieving plate 204 to leave the sieving plate 204 and fall on the side wall of the top pipeline 401 of the powder falling device, and the residual powder on the sieving plate 204 completely moves to the side wall of the top pipeline 401 of the powder falling device, so that the residual powder completely falls on the bottom partition 404 of the fourth powder falling device 44;

The central controller then instructs to open the partition between the fourth powder separator movement mechanism 24 and the third powder separator movement mechanism 23 so that the remaining powder except for the fourth powder particle size continues to fall, the third powder particle size stays on the sieving plate 204 of the third powder separator movement mechanism 23, the remaining powder falls on the partition between the third powder separator movement mechanism 23 and the first powder separator movement mechanism 21, and the above operation is repeated until the fourth, third, second and first powder particle sizes in the powder fall on the bottom partition 404 of the fourth, third, first and second powder falling devices 44, 43, 41 and 42, respectively;

then the central controller gives an instruction to open the bottom partition 404 of the fourth powder falling device 44, the fourth-particle-size powder particles fall onto the powder spreading plate 51, then the central controller gives an instruction to control the second powder spreading plate lower powder opening 54 to be closed and the first powder spreading plate lower powder opening 52 to be opened, then the scraper 55 is controlled to start moving, the scraper 55 pushes the fourth-particle-size powder particles onto the forming substrate 53, the redundant powder enters the powder recovery system through the first powder spreading plate lower powder opening 52, and then the scraper 55 moves to the initial position at the left end again;

The central controller gives an instruction to open the bottom partition 404 of the third powder falling device 43, the third-particle-size powder particles fall onto the powder spreading plate 51, then the doctor blade 55 is controlled to start moving, the doctor blade 55 pushes the third-particle-size powder particles onto the forming substrate 53, the excessive powder enters the powder recovery system through the first powder spreading plate powder discharging port 52, then the doctor blade 55 moves to the rightmost end of the powder spreading plate 51, and thus the third-particle-size powder particle layer is spread onto the fourth-particle-size powder particle layer;

the central controller gives an instruction to close the first powder laying plate lower powder opening 52, simultaneously opens and opens the second powder laying plate lower powder opening 54 and the bottom partition 404 of the first powder falling device 41, the second-particle-size powder particles fall onto the powder laying plate 51, then the doctor blade 55 is controlled to start moving leftwards, the doctor blade 55 pushes the second-particle-size powder particles onto the forming substrate 53, the excessive powder enters the powder recovery system through the second powder laying plate lower powder opening 54, so that the second-particle-size powder particle layer is laid onto the third-particle-size powder particle layer, and then the doctor blade 55 moves to the rightmost end of the powder laying plate 51 again;

the central controller gives an instruction to open the bottom partition 404 of the second powder falling device 42, the first particle size powder particles fall onto the powder spreading plate 51, then the doctor 55 is controlled to start moving leftwards, the doctor 55 pushes the first particle size powder particles onto the forming substrate 53, excessive powder enters the powder recycling system through the powder opening 54 under the second powder spreading plate, so that the powder layer is prepared to be divided into a first particle size powder particle layering, a second particle size powder particle layering, a third particle size powder particle layering and a fourth particle size powder particle layering from top to bottom, the lower part of the powder layer is a fourth particle size powder particle layering, the middle lower part of the powder layer is a third particle size powder particle layering, the middle lower part of the powder layer is a small amount of second particle size powder particles and the first particle size powder particles, the middle upper part of the powder layer is a second particle size powder particle layering, the middle upper part of the powder layer is a small amount of first particle size powder particles layering;

And finally, the central controller sends out an instruction, removes the device of the powder discharging screening channel box assembly 1, then starts a single-layer laser scanning process, the space of the powder layer of the type is basically filled from bottom to top, after the single-layer scanning is finished, the operation process is repeated, the density of the formed workpiece is far higher than that of the workpiece formed by the traditional powder paving mode, and the mechanical property of the formed workpiece is also greatly improved due to the far improved density, so that the requirement of practical application can be met.

Those skilled in the art will appreciate that the invention provides a system and its individual devices, modules, units, etc. that can be implemented entirely by logic programming of method steps, in addition to being implemented as pure computer readable program code, in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers, etc. Therefore, the system and various devices, modules and units thereof provided by the invention can be regarded as a hardware component, and the devices, modules and units for realizing various functions included in the system can also be regarded as structures in the hardware component; means, modules, and units for implementing the various functions may also be considered as either software modules for implementing the methods or structures within hardware components.

In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.

The foregoing describes specific embodiments of the present application. It is to be understood that the application is not limited to the particular embodiments described above, and that various changes or modifications may be made by those skilled in the art within the scope of the appended claims without affecting the spirit of the application. The embodiments of the application and the features of the embodiments may be combined with each other arbitrarily without conflict.

Claims (10)

1. Powder supplying and paving integrated device for improving workpiece compactness is characterized by comprising the following components: a powder discharging screening channel box assembly (1), a powder separator moving mechanism assembly, a powder falling device assembly, a powder paving plate (51) and a central controller;

The powder separator motion mechanism assembly includes a plurality of powder separator motion mechanisms mounting a screening plate (204);

a plurality of powder separator moving mechanisms are arranged on the periphery side of the powder discharging screening channel box assembly (1) from top to bottom, and a plurality of screening plates (204) are allowed to move into the powder discharging screening channel box assembly (1);

the filtering pore diameters of the screening plates (204) are gradually reduced from top to bottom, and powder is gradually screened by the screening plates (204) according to the filtering pore diameters after being placed into a channel of the lower powder screening channel box assembly (1);

the powder falling device assembly is arranged above the powder paving plate (51), and comprises a plurality of powder falling devices;

-said sieving plates (204) allowing movement to and one-to-one correspondence with said powder falling means, -said sieving plates (204) allowing placement of powder into correspondence with said powder falling means;

the central controller is electrically connected with the powder discharging screening channel box assembly (1), the powder separator moving mechanism assembly, the powder falling device assembly and the powder paving plate (51).

2. The powder feed integration apparatus for improving workpiece compactness of claim 1, wherein the powder separator movement mechanism comprises: a linear guide (201), a linear guide sliding accessory (202), a box (203), a rotating shaft (205), a speed reducer (206), a first motor (207), a motor bracket (208), a rack belt (209), a gear (210) and a second motor (211);

the box body (203) is provided with the linear guide rail sliding accessory (202) and the rack belt (209), and one end of the linear guide rail (201) is fixedly connected with the powder discharging screening channel box assembly (1) and is in sliding fit connection with the linear guide rail sliding accessory (202);

the second motor (211) is fixedly connected with the powder discharging screening channel box assembly (1), the gear (210) is arranged at the output end of the second motor (211), the gear (210) is meshed with the rack belt (209), and the second motor (211) is meshed with the rack belt (209) through the gear (210) to drive the box body (203) to move;

the first motor (207) is fixedly arranged in the box body (203) through the motor bracket (208), the output end of the first motor (207) is provided with the speed reducer (206), and the speed reducer (206) is connected with the screening plate (204) through the rotating shaft (205);

The central controller is electrically connected with and controls the first motor (207) to drive the screening plate (204) to overturn, and the central controller controls the second motor (211) to drive the gear (210) to rotate and drive the screening plate (204) to horizontally move relative to the powder discharging screening channel box assembly (1).

3. Powder spreading integrated device for improving workpiece compactness according to claim 2, characterized in that the lower powder screening channel box assembly (1) comprises: a ball valve (11), a top plate (12), a main box plate (13), a partition plate and a side plate (14);

the side plates (14) are arranged on the side surfaces of the main box body plate (13), the top plate (12) is arranged on the top of the main box body plate (13), and a cavity is formed by surrounding the main box body plate (13), the side plates (14) and the top plate (12);

the side surface of the main box body plate (13) is provided with a plurality of rectangular through holes, the rectangular through holes are communicated with the cavity, a plurality of partition plates are arranged in the cavity, and the screening plate (204) is allowed to move into the cavity through the rectangular through holes;

the partition board is arranged between the adjacent powder separator moving mechanisms, and the central controller is electrically connected with and controls the partition board to turn over in the cavity;

The ball valve (11) is installed on the top plate (12), a powder amount monitoring module is installed in the ball valve (11), powder is allowed to be placed in the cavity by opening the ball valve (11), and the central controller is electrically connected with the ball valve (11).

4. A powder feed integration apparatus for increasing workpiece compactness as defined in claim 3, wherein the powder separator movement mechanism assembly comprises: a first powder separator movement mechanism (21), a second powder separator movement mechanism (22), a third powder separator movement mechanism (23), and a fourth powder separator movement mechanism (24);

the fourth powder separator moving mechanism (24), the third powder separator moving mechanism (23), the first powder separator moving mechanism (21) and the second powder separator moving mechanism (22) are arranged on the side surface of the lower powder screening channel box assembly (1) from top to bottom;

the powder is respectively screened into second-particle-size powder particles, first-particle-size powder particles, third-particle-size powder particles and fourth-particle-size powder particles by the first-powder-separator moving mechanism (21), the second-powder-separator moving mechanism (22), the third-powder-separator moving mechanism (23) and the fourth-powder-separator moving mechanism (24);

The first particle size powder particles, the second particle size powder particles, the third particle size powder particles, and the fourth particle size powder particles increase in size in order.

5. The powder feed and distribution integrated device for improving workpiece compactness according to claim 4, wherein the powder dropping device comprises: a powder falling device top pipe (401), an electrified magnetic pole device (402), a powder falling device bottom pipe (403) and a bottom partition plate (404);

the powder falling device top pipeline (401) is connected with the powder falling device bottom pipeline (403), and the electrified magnetic pole device (402) is arranged between the powder falling device top pipeline (401) and the powder falling device bottom pipeline (403);

the end of the bottom pipeline (403) of the powder falling device, which is opposite to the top pipeline (401) of the powder falling device, is provided with the bottom baffle (404), and the bottom baffle (404) allows the bottom pipeline (403) of the powder falling device to be pulled away;

the powder is allowed to be transferred to the position above the top pipeline (401) of the powder falling device through the screening plate (204), and the powder is poured into the top pipeline (401) of the powder falling device through the screening plate (204) driven to turn over by the first motor (207).

6. Powder spreading integration device for improving workpiece compactness according to claim 5, characterized in that the powder falling device assembly comprises a first powder falling device (41), a second powder falling device (42), a third powder falling device (43) and a fourth powder falling device (44);

the fourth particle size powder particles are conveyed by the fourth powder separator motion mechanism (24) and are poured into the fourth powder falling device (44);

the third-size powder particles are conveyed by the third powder separator moving mechanism (23) and are poured into the third powder falling device (43);

the second-size powder particles are conveyed by the first powder separator moving mechanism (21) and are poured into the first powder falling device (41);

the first size powder particles are transported by the second powder separator movement mechanism (22) and are poured into the second powder falling device (42).

7. The powder supply and spreading integrated device for improving workpiece compactness according to claim 6, wherein: a magnetic pole plate is correspondingly arranged above the powder falling device;

the central controller is electrically connected with and controls the magnetic pole plate and the electrified magnetic pole device (402) to be electrified, when the magnetic pole plate and the electrified magnetic pole device (402) are electrified, a magnetic field is formed between the magnetic pole plate and the electrified magnetic pole device (402), and the powder is attached to the powder falling device top pipeline (401) from the screening plate (204) through the magnetic field;

When the magnetic pole plate and the electrified magnetic pole device (402) are powered off, the powder falls to the bottom of the powder falling device;

the central controller is electrically connected with and controls the bottom partition plate (404) to be pulled away, and when the bottom partition plate (404) is pulled away, the powder falls down and is spread on the powder spreading plate (51).

8. The powder feed integration apparatus for improving workpiece compactness of claim 7, wherein the magnetic plate comprises: a first magnetic plate (31), a second magnetic plate (32), a third magnetic plate (33), and a fourth magnetic plate (34);

the first magnetic plate (31) is arranged above the first powder falling device (41), the second magnetic plate (32) is arranged above the second powder falling device (42), the third magnetic plate (33) is arranged above the third powder falling device (43), and the fourth magnetic plate (34) is arranged above the fourth powder falling device (44).

9. The powder supply and spreading integrated device for improving workpiece compactness according to claim 8, wherein: a molding substrate (53) is arranged on the powder spreading plate (51), a first powder spreading plate lower powder opening (52) and a second powder spreading plate lower powder opening (54) are respectively arranged on two sides of the molding substrate (53), and the central controller is electrically connected with and controls the opening and closing of the first powder spreading plate lower powder opening (52) and the second powder spreading plate lower powder opening (54);

A scraper (55) is arranged at one end of the powder spreading plate (51), a forming cylinder lifting mechanism (6) is arranged at the bottom of the powder spreading plate (51), the central controller is electrically connected with and controls the scraper (55) to move along the extending direction of the powder spreading plate (51), and the central controller is electrically connected with the forming cylinder lifting mechanism (6);

the lower powder screening channel box assembly (1) is provided with a moving mechanism, and the central controller is electrically connected with and controls the moving mechanism to drive the lower powder screening channel box assembly (1) to move in the horizontal plane along the direction vertical to the powder paving plate (51).

10. A method of operating a powder feeder assembly for increasing workpiece compactness as defined in claim 9, comprising the steps of:

step S1, the central controller controls four screening plates (204) to move into the main box body plate (13), and the central controller controls the partition plates to be in a closed state;

step S2, the central controller controls the ball valve (11) to be opened, the powder enters the cavity through the ball valve (11), the powder particles with the fourth particle size stay on the uppermost screening plate (204), and the rest of the powder falls on a partition plate between the third powder separator moving mechanism (23) and the fourth powder separator moving mechanism (24);

Step S3, the central controller controls the fourth powder separator moving mechanism (24) to move to the position right above the fourth powder falling device (44) through the second motor (211) of the fourth powder separator moving mechanism (24), the central controller controls the sieving plate (204) of the fourth powder separator moving mechanism (24) to turn 180 degrees through the first motor (207) of the fourth powder separator moving mechanism (24), most of the fourth particle size powder particles fall on a bottom partition plate (404) of the fourth powder falling device (44), as a result of a certain amount of the fourth particle size powder particles still adhering to the sieving plate (204) of the fourth powder separator moving mechanism (24), the central controller energizes the fourth magnetic pole plate (34) and the energizing magnetic pole device (402) of the fourth powder falling device (44), the formed magnetic field coacts to make the fourth particle size particles adhered to the sieving plate (204) of the fourth powder separator moving mechanism (24) fall on the fourth particle size powder falling device (44) to the top wall of the fourth powder falling device (401), the fourth particle size particles remain on the fourth powder falling device (44) completely falls off the top of the powder falling device (44), the fourth particle size powder particles remaining on the side wall fall completely onto the bottom partition (404) of the fourth powder falling device (44);

Step S4, the central controller controls to open a partition plate between the third powder separator moving mechanism (23) and the fourth powder separator moving mechanism (24), the third particle size powder particles fall and stay on a screening plate (204) of the third powder separator moving mechanism (23), and the rest of powder fall on the partition plate between the third powder separator moving mechanism (23) and the first powder separator moving mechanism (21), and the third powder separator moving mechanism (23), the first powder separator moving mechanism (21) and the second powder separator moving mechanism (22) sequentially repeat the operation method of the fourth powder separator moving mechanism (24) in step S3 until the fourth particle size powder particles, the third particle size powder particles, the second particle size powder particles, the first particle size powder particles fall on the partition plate (404) of the fourth powder falling device (44), the third powder falling device (43), the first powder falling device (41) and the second powder falling device (42) respectively;

step S5, the central controller controls to open a bottom partition plate (404) of the fourth powder falling device (44), fourth powder particles with the particle sizes fall onto the powder spreading plate (51), the central controller controls to close a powder opening (54) under the second powder spreading plate and open a powder opening (52) under the first powder spreading plate, the central controller controls the scraper (55) to move, the scraper (55) pushes the fourth powder particles with the particle sizes onto the forming substrate (53), redundant fourth powder particles enter a powder recovery system through the powder opening (52) under the first powder spreading plate, and the scraper (55) moves to an initial position at the left end of the powder spreading plate (51) again;

Step S6, the central controller controls to open a bottom partition plate (404) of the third powder falling device (43), third particle size powder particles fall onto the powder spreading plate (51), the central controller controls the scraper (55) to move, the scraper (55) pushes the third particle size powder particles onto the forming substrate (53), the rest third particle size powder particles enter a powder recovery system through a powder outlet (52) of the first powder spreading plate, the scraper (55) moves to the rightmost end of the powder spreading plate (51), and the third particle size powder particle layer is spread onto fourth particle size powder particles;

step S7, the central controller controls to close the first powder paving plate powder discharging opening (52) and simultaneously open the second powder paving plate powder discharging opening (54) and a bottom partition plate (404) of the first powder falling device (41), the second particle size powder particles fall onto the powder paving plate (51), the central controller controls the scraper (55) to start moving leftwards, the scraper (55) pushes the second particle size powder particles onto the forming substrate (53), the redundant second particle size powder particles enter a powder recovery system through the second powder paving plate powder discharging opening (54), the second particle size powder particle layers are paved on the third particle size powder particle layers, and then the scraper (55) moves to the rightmost end of the powder paving plate (51) again;

Step S8, the central controller controls to open a bottom partition plate of a second powder falling device (42), the first-particle-size powder particles fall onto the powder spreading plate (51), the central controller controls the scraper (55) to move leftwards, the scraper (55) pushes the first-particle-size powder particles onto the forming substrate (53), redundant first-particle-size powder particles enter a powder recovery system through a powder outlet (54) of the second powder spreading plate, a first-particle-size powder particle layer is spread onto the second-particle-size powder particles, and the scraper (55) moves to the left initial position of the powder spreading plate (51) again;

after the powder layer is paved, the powder layer is divided into the first particle size powder particle, the second particle size powder particle, the third particle size powder particle and the fourth particle size powder particle from top to bottom, the lower part of the powder layer is the fourth particle size powder particle, the middle part of the fourth particle size powder particle is mixed with the first particle size powder particle, the second particle size powder particle and the third particle size powder particle, the middle part of the third particle size powder particle is mixed with the first particle size powder particle and the second particle size powder particle, the middle part of the second particle size powder particle is mixed with the first particle size powder particle, and the upper part of the powder layer is the first particle size powder particle;

And S9, after the central controller controls the powder discharging screening channel box assembly (1) to be removed, starting a single-layer laser scanning process, and repeating the operation processes from the step S1 to the step S8 after the single-layer laser scanning is completed.