CN112140542A

CN112140542A - Powder supply device and powder supply method for powder bed

Info

Publication number: CN112140542A
Application number: CN202010999669.1A
Authority: CN
Inventors: 俞红祥; 庞伟; 黄少俯
Original assignee: Hangzhou Dedi Intelligent Technology Co ltd
Current assignee: Hangzhou Dedi Intelligent Technology Co ltd
Priority date: 2020-09-22
Filing date: 2020-09-22
Publication date: 2020-12-29

Abstract

The present invention relates to a powder supplying apparatus and a powder supplying method for a powder bed. The powder supplying apparatus includes: a support; the forming mechanism is arranged on the support and comprises a forming cylinder with an inner cavity and a lifting platform which can move in the inner cavity of the forming cylinder, and the lifting platform supports a printing substrate; and a powder supply mechanism arranged on the support and including a powder bin, a lifting unit and a powder spreading unit, wherein the powder bin has an inner cavity and an inlet and an outlet communicated with the inner cavity and respectively located at two opposite sides of the printing substrate, the lifting unit has a bearing element which can move in the inner cavity to send out powder from the powder bin, and the powder spreading unit has a powder spreading element which can move from the outlet to the inlet to push the sent powder. The powder supply device integrates powder storage, powder supply, powder spreading and powder returning, has compact powder path, simple control, reliable action and high powder supply speed, and can directly recycle the residual powder.

Description

Powder supply device and powder supply method for powder bed

Technical Field

The invention relates to the technical field of 3D printing of powder beds, in particular to a powder supply device and a powder supply method for a powder bed.

Background

The powder bed 3D printer is one of the important branches of additive manufacturing equipment, and adopts the forming principle of spreading powder layer by layer and selectively heating the area powder, so that the powder bed 3D printer has the advantages of high forming freedom degree, high size precision, good surface quality, low dependence of a supporting structure, simple post-treatment and the like.

In recent years, 3D printers have begun to spread in the field of manufacturing of a large number of consumer products, and the spread of 3D printers in turn has stimulated the upgrade thereof to higher processability and higher production efficiency. However, during the development of 3D printers, one important system affecting the performance of powder bed 3D printers: the powder system is still in a state of slow development or even stagnation. The existing powder path assembly is not only complex in structure and large in volume, but also poor in sealing effect and difficult to operate and maintain.

At present, the 3D printing powder supply technology which is compact in structure, reliable in action, high in powder supply and powder laying speed and high in powder one-time utilization efficiency is required in the industry.

Disclosure of Invention

Based on the above, the invention provides a powder supply device for a powder bed and a powder supply method for the powder bed, which have compact structure, can realize direct recycling of residual powder and have high powder supply efficiency.

According to an embodiment of the present invention, there is provided a powder supplying apparatus for a powder bed, including: a support; the forming mechanism is arranged on the support and comprises a forming cylinder with an inner cavity and a lifting platform which can move in the inner cavity of the forming cylinder, and the lifting platform supports a printing substrate; and a powder supply mechanism arranged on the support and including a powder bin, a lifting unit and a powder spreading unit, wherein the powder bin has an inner cavity and an inlet and an outlet communicated with the inner cavity and respectively located at two opposite sides of the printing substrate, the lifting unit has a bearing element which can move in the inner cavity to send out powder from the powder bin, and the powder spreading unit has a powder spreading element which can move from the outlet to the inlet to push the sent powder.

According to the powder supply device of the invention, the forming mechanism and the powder supply mechanism are both formed on the bracket, and the structure is compact. The entry and the export in powder storehouse are located the relative both sides of the jar that takes shape respectively, can directly make the powder lay on printing the base plate from a side to opposite side propelling movement in-process with the powder, and directly push back powder storehouse recycle with surplus powder after laying the completion, simple operation can realize the function of spreading the powder and retrieving the powder, it is extravagant not only to produce surplus powder, and need not the accurate metering means of the powder volume of any form, only need when setting up the inching time of powder hoisting unit, with the biggest single powder volume of supplying as the prerequisite, it can to keep enough redundancy volume. The powder supply device integrates powder storage, powder supply, powder spreading and powder returning, has reliable action, high powder supply speed and direct recycling of residual powder, has compact powder path, simple control, good powder supply continuity and high powder one-time utilization rate, and is easy to popularize and apply in powder three-dimensional forming equipment with various specifications.

In one embodiment, the sides of the print substrate form a sliding sealing fit with the inner wall of the forming cylinder. Thus, the powder laid on the printing substrate can be prevented from falling into the powder bin or being clamped between the printing substrate and the inner wall of the forming cylinder, and the normal powder laying operation is prevented from being hindered.

In one embodiment, the lifting unit includes: a first drive wheel disposed on the support corresponding to the outlet; a first driven wheel arranged in the powder bin; the first transmission belt is sleeved on the first driving wheel and the first driven wheel; wherein a plurality of carrier elements are spaced apart on the first conveyor belt, each carrier element being configured to be reversible upon exiting the outlet to deliver powder onto the support. The lifting unit is simple in structure and easy to implement, can work during the working period of the powder spreading unit, and can realize continuous and uninterrupted powder spreading by matching the lifting unit and the powder spreading unit, namely, powder supply at two sides is not needed, and the reciprocating waiting time of the scraper is also avoided.

In one embodiment, the powder spreading unit includes: a second drive wheel disposed adjacent the outlet; a second driven wheel disposed adjacent the inlet; the second conveying belt is sleeved on the second driving wheel and the second driven wheel and stretches across the printing substrate; wherein the powder spreading member is disposed on the second conveyor belt and configured such that a top thereof abuts a top surface of the holder during movement from the outlet to the inlet. The powder paving unit disclosed by the invention is simple in structure and easy to implement, and can continuously and circularly pave powder and improve the efficiency.

In one embodiment, the bracket is provided with a powder falling guide plate, the powder falling guide plate is positioned between the first driving wheel and the second driving wheel to guide the powder sent by the bearing element to the bracket, and the thickness of one side of the powder falling guide plate close to the first driving wheel is larger than that of one side close to the second driving wheel. The powder falling guide plate can guide the powder sent out by the lifting unit to be accumulated into a powder pile at the preset position of the bracket, so that the powder spreading element of the powder spreading unit can push and spread the powder in sequence.

In one embodiment, the powder hopper includes: a first vertical section and a second vertical section arranged in opposition, wherein the first vertical section defines the outlet and the second vertical section defines the inlet; the transverse section is connected between the first vertical section and the second vertical section, and the transverse section, together with the first vertical section and the second vertical section, defines an inner cavity of the powder bin; wherein the forming cylinder is located in a concave space defined by the first vertical section, the second vertical section, and the transverse section, and the first driven wheel is disposed in the first vertical section.

In one embodiment, the lifting platform comprises a lifting rod movably arranged on the transverse section of the powder bin, the top of the lifting rod extends into the inner cavity of the powder bin, and the lifting platform is arranged on the top of the lifting rod. The powder bin is in a U-shaped structure surrounding the forming cylinder, is compact in structure and is easy to realize powder feeding and powder recovery.

In one embodiment, a stirrer is arranged in the inner cavity of the powder bin; and/or a vibrator is arranged on the wall of the powder bin. The stirrer stirs the powder in the powder bin, so that the problem of hardening caused by long-time accumulation of a large amount of powder can be prevented, the problem of uneven powder plane in the powder bin caused by uneven distribution of the residual powder can be effectively solved, and the reliability and consistency of continuous powder supply are further ensured. The vibrator drives the bin wall of the powder bin to vibrate, and prevents powder from being adhered to the bin wall to cause blockage in the long-term operation process.

There is also provided, in accordance with an embodiment of the present invention, a powder supply method for a powder bed, including: moving the printing substrate to a preset position and positioning; lifting the powder from the powder bin to an outlet on one side of the printing substrate away from the powder bin and accumulating the powder on a supporting surface; pushing the accumulated powder in a direction from the one side to the opposite side of the printing substrate so that at least a part of the powder is laid on the printing substrate; pushing the remaining powder in the direction continues until it falls into the inlet of the powder bin on the other side of the print substrate.

In one embodiment, the powder on the support surface is pushed by a powder spreading element movable between an outlet and an inlet of the powder hopper, the powder spreading element being configured to abut the support surface at its top during movement from the outlet to the inlet; moving and positioning the print substrate to a predetermined position includes: and moving the printing substrate to be positioned when the height difference between the top surface of the printing substrate and the supporting surface is the single-layer powder spreading thickness.

Drawings

Fig. 1 is a three-dimensional schematic view of a powder supply apparatus according to an embodiment of the present invention;

fig. 2 is a plan view of a powder supplying apparatus according to an embodiment of the present invention;

FIG. 3 is an enlarged view of FIG. 2 at A;

fig. 4 is a control signal connection diagram of the powder supplying apparatus according to the embodiment of the present invention;

fig. 5 to 7 are schematic views illustrating a powder lifting process according to an embodiment of the present invention, wherein fig. 5 is an overall schematic view illustrating a lifting unit lifting powder, fig. 6 is an enlarged view at B of fig. 5, and fig. 7 is a schematic view illustrating a continued movement of the carrying element in fig. 6;

fig. 8 to 12 are schematic views of a cyclic powder laying process according to an embodiment of the present invention, in which fig. 8 is a schematic view of powder being accumulated on a carriage, fig. 9 is a schematic view of starting powder laying, fig. 10 is a schematic view of a powder laying member pushing powder to be laid on a printing substrate, fig. 11 is a schematic view of the powder laying member continuing to push powder toward an inlet of a powder hopper, and fig. 12 is a schematic view of completion of one powder laying cycle.

Description of the element reference numerals

1. A support; 11. a frame; 12. a top plate; 121. a first opening; 122. a second opening; 123. a third opening; 2. a forming mechanism; 21. a forming cylinder; 211. an inner cavity; 22. a lifting platform; 221. a support plate; 222. a lifting rod; 23. printing a substrate; 3. a powder supply mechanism; 31. a powder bin; 311. a first vertical section; 312. a second vertical section; 313. a transverse segment; 32. a stirrer; 33. a vibrator; 34. a lifting unit; 341. a first drive wheel; 342. a first driven wheel; 343. a first conveyor belt; 344. a carrier element; 35. a powder spreading unit; 351. a second drive wheel; 352. a second driven wheel; 353. a second conveyor belt; 354. spreading a powder element; 36. a powder falling guide plate; 4. powder; 5. and a controller.

The present invention is described in further detail with reference to the drawings and the detailed description.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and the detailed description. It should be understood that the detailed description and specific examples, while indicating the scope of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

It will be understood that when an element is referred to as being "mounted on" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. When an element is referred to as being "secured to" another element, it can be directly secured to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

Fig. 1 and 2 show in their entirety a powder supply device according to one embodiment of the invention, which can be applied to or as part of a powder bed, for example, wherein fig. 1 is a three-dimensional schematic view of the powder supply device and fig. 2 is a plan view of the powder supply device. As shown in fig. 1 and 2, the powder supplying apparatus includes a stand 1, and a forming mechanism 2 and a powder supplying mechanism 3 mounted on the stand 1. A top plate 12 is laid on the frame 11 of the bracket 1, and the upper surface (or called top surface, support surface) of the top plate 12 is substantially plane. The top plate 12 has a first opening 121 corresponding to the forming mechanism 2 and second and

third openings

122 and 123 corresponding to the powder supply mechanism 3. The top plate 12 and the frame 11 may be integrally formed as a single piece or may be separate pieces that are welded, bonded, etc.

The forming cylinder 21 of the forming mechanism 2 is mounted on the frame 11, and the top of the forming cylinder 21 extends into the first opening 121 of the top plate 12, so that the upper opening of the inner cavity 211 of the forming cylinder 21 is embedded in the first opening 121 of the top plate 12 and the upper surface of the forming cylinder 21 is flush with the upper surface of the top plate 12. A lift table 22 is provided in the inner cavity 211 of the forming cylinder 21 to support and position the print substrate 23. In the illustrated embodiment, the lift pins 222 of the lift table 22 are mounted on the powder supply mechanism 3 so as to be movable up and down, while the support plate 221 is supported at the tip ends of the lift pins 222, and the print substrate 23 is fixedly laid on the support plate 221. In some embodiments, the side of the printing substrate 23 forms a sliding sealing fit with the inner wall of the forming cylinder 21 enclosing the inner cavity 211, preventing powder laid on the printing substrate 23 or powder on the bracket 1 from falling into the inner cavity 211 of the forming cylinder 21 or remaining between the printing substrate 23 and the forming cylinder 21 to affect the normal powder laying operation of the device. The elevating table 22 can drive the printing substrate 23 to move up and down and be positioned in the forming cylinder 21. When the lift table 22 is raised to the top dead center, the upper surface of the print substrate 23 is flush with the upper surface of the top plate 12.

The powder supply mechanism 3 includes a powder hopper 31, a lifting unit 34, and a powder laying unit 35. As shown in fig. 1 and 2, in the illustrated embodiment, the powder hopper 31 is substantially U-shaped or concave, and includes a first vertical section 311 located on one side of the forming cylinder 21, a second vertical section 312 arranged on the other side of the forming cylinder 21 opposite to the first vertical section 311, and a transverse section 313 connected between the first vertical section 311 and the second vertical section 312 and located below the forming cylinder 21. Wherein the first vertical section 311, the second vertical section 312 and the transverse section 313 are each hollow tube sections, which together define an inner cavity of the powder bin 31 for containing the powder 4. The first vertical section 311 defines an outlet of the powder bin 31, which is arranged corresponding to the second opening 122 of the top plate 12, for example, the first vertical section 311 may be extended into the second opening 122, so that the outlet is embedded in the second opening 122. The second vertical section 312 defines an inlet of the powder bin 31, which is arranged corresponding to the third opening 123 of the top plate 12, for example, the second vertical section 312 can be made to extend into the third opening 123, so that the inlet is embedded in the third opening 123. As shown in fig. 1 and 2, the outlet and the inlet of the powder hopper 31 are located on opposite sides of the print substrate 23, respectively. Although the drawings show only an embodiment in which the powder hopper 31 has a U shape, those skilled in the art will appreciate that the specific shape of the powder hopper 31 is not limited thereto, and changes in shape may be made as needed as long as the inlet and outlet of the powder hopper 31 are provided on opposite sides of the printing substrate 23 or the forming cylinder 21, respectively.

In the illustrated embodiment, the lift lever 222 of the lift table 22 is movably mounted on the lateral section 313 of the powder hopper 31, and the lower opening of the inner cavity 211 of the forming cylinder 21 communicates with the lateral section 313 so that the lift lever 222 can extend into the inner cavity 211 and support the printing substrate 23 in the inner cavity 211 to move up and down and be positioned. According to the embodiment of the present invention, the lower opening of the forming cylinder 21 communicates with the transverse section 313 of the powder bin 31, and once the sliding seal between the printing substrate 23 and the inner wall of the forming cylinder 21 becomes poor or even fails, the powder in the forming cylinder 21 can directly fall into the bottom of the U-shaped powder bin 31 without leaking to the outside of the powder bin 31, thereby preventing the safety of equipment and operators from being compromised.

In some embodiments, a vibrator is provided on the wall of the powder hopper 31 to prevent powder from remaining on the wall of the powder hopper. As shown in fig. 1 and 2, a plurality of vibrators 33 may be provided on outer walls of the first vertical section 311 and the second vertical section 312 of the powder hopper 31, respectively, to drive walls of the first vertical section and the second vertical section to vibrate, preventing powder from adhering to the walls of the first vertical section and the second vertical section.

In some embodiments, an agitator 32 is provided within the powder hopper 31 to prevent the powder 4 from agglomerating or caking. As shown in fig. 2, the stirrer 32 is sleeved on the lifting rod 222 in the inner cavity of the powder bin 31 and can rotate around the lifting rod 222. The speed of rotation of the agitator 32 may be constant or variable. The slow agitation of the powder 4 by the agitator 32 may cause the powder 4 to be in a slow flowing state, so that the powder 4 is uniformly distributed and prevented from hardening in the powder bin 31, particularly in the transverse section 313.

The lifting unit 34 is disposed in the first vertical section 311 of the powder hopper 31, and is configured to lift the powder 4 in the powder hopper 31 and deliver the powder through the outlet of the powder hopper 31 onto the top surface of the top plate 12, and form a powder pile having a width not smaller than the width of the printing substrate 23 on one side of the forming cylinder 21, in preparation for a subsequent powder laying operation. The top surface of the top plate 12 or the top surface of the holder 1 here serves as a support surface for the powder being fed out. In the illustrated embodiment, the lifting unit 34 is configured in a belt-and-pulley conveying manner, and includes a first driving pulley 341 provided on the top plate 12 corresponding to the outlet of the powder hopper 31, a first driven pulley 342 provided at the bottom of the powder hopper 31 below the first driving pulley 341, a first conveying belt 343 fitted over the first driving pulley 341 and the first driven pulley 342, and a plurality of bearing members 344 arranged at intervals on the first conveying belt 343. The position of the carrier member 344 corresponds to the position of the print substrate 23 in plan view, and the width of the carrier member 344 is not smaller than the width of the print substrate 23. The support element 344 can be designed, for example, as an open powder reservoir. As shown in fig. 5 to 7, with the clockwise movement of the first conveyor belt 343, the carrier member 344 located below the first driven pulley 342 is submerged in the powder 4 with the opening of the carrier member 344 facing upward, and during the rising of the left side of the first conveyor belt 343, the carrier member 344 in a raised state is filled with the powder 4 and lifts up carrying the powder 4. After passing around the highest point of the first pulley 341, the ascending carrier 344 gradually turns from the upward-opening posture to the downward-opening posture following the circumferential contour of the first pulley 341, so that the powder 4 carried by it falls by gravity onto the top plate 12. In some embodiments, the first conveyor belt 343 may be a flexible belt.

In some embodiments, the first driving wheel 341 and the first driven wheel 342 of the lifting unit 34 are of a two-piece structure, the first conveying belt 343 is engaged with the two-piece first driving wheel 341 and the two-piece first driven wheel 342 through the positioning holes at two sides, the contact area of the engaging portion between the first driving wheel 341 and the first driven wheel 342 and the first conveying belt 343 is small, and the problems of a large amount of powder clamping and powder clamping cannot occur.

The rotation angle of the first driving wheel 341 is equal to the number of the carrying elements 344 driven and turned by the first driving wheel. The rotation angle of the first driving wheel 341 can be controlled by the controller, so that the amount of the powder lifted to the bracket 1 by the lifting unit 34 can be adjusted.

According to the lifting unit provided by the embodiment of the invention, the bearing elements on the first conveying belt can adopt different capacities and different distribution intervals, the larger the capacity and the smaller the distribution interval of a single bearing element are, the larger the minimum turning radius of the conveying belt is, the smaller the rotation angle required by the first driving wheel for supplying powder at each time is, and otherwise, the smaller the minimum turning radius of the conveying belt is, the larger the rotation angle required by the first driving wheel for supplying powder at each time is. The lifting unit of the present invention can also adopt other mechanical and pneumatic powder lifting methods besides the embodiment.

Although the drawings show only an embodiment in which the carrier member 344 moves with the first conveyor belt 343 and turns around the first driving wheel 341, those skilled in the art will appreciate that the structure of the lifting unit 34 is not limited thereto, and the configuration may be changed as needed as long as the powder 4 can be fed out from the powder hopper 31 and onto the top plate 12 by the movable carrier member 344. For example, in one embodiment, not shown, the carrier element itself may be tiltable about a pivot axis, which may be, for example, a mounting axis for mounting the carrier element to the first conveyor belt. When the carrier element carries the powder out of the outlet of the powder bin, the carrier element can be controlled to flip around a pivot axis or autonomously under gravity to dump the powder onto the top plate 12.

A powder spreading unit 35 is provided on the carriage 1 and downstream of the lifting unit 34 to push the powder accumulated on the top plate 12 to the print substrate 23 to perform a powder spreading operation and push the remaining powder 4 into the inlet of the powder hopper 31, thereby achieving direct recovery of the remaining powder. In the illustrated embodiment, the powder spreading unit 35 includes a second driving wheel 351 provided on the support 1 near the outlet of the powder bin 31, a second driven wheel 352 provided on the support 1 near the inlet of the powder bin 31, a second conveying belt 353 fitted over the second driving wheel 351 and the second driven wheel 352, and two powder spreading members 354 mounted on the second conveying belt 353 at intervals. After the second driving pulley 351 and the second driven pulley 352 tension the second conveyor belt 353, one end of the powder laying unit 35 is located on one side of the forming cylinder 21 and the other end is located on the opposite side of the forming cylinder 21 and crosses over the inlet of the powder hopper 31 so that the second conveyor belt 353 crosses over the first opening 121 of the top plate 12, the forming cylinder 21 and the inlet of the powder hopper 31. In some embodiments, the second conveyor belt 353 may be a flexible belt.

In some embodiments, the second driving wheel 351 and the second driven wheel 352 of the powder spreading unit 35 are of a two-piece structure, the second conveying belt 353 is meshed with the two-piece second driving wheel 351 and the two-piece second driven wheel 352 through the positioning holes at two sides, the contact area of the meshed parts of the second driving wheel 351 and the second driven wheel 352 and the second conveying belt 353 is small, and the problems of a large amount of powder clamping and powder clamping cannot occur.

Two powder spreading elements 354 are symmetrically fixed on the second conveyor belt 353. As shown in fig. 2 and 8 to 12, before the powder spreading starts, the second driving wheel 351 is in a locked state, in which one powder spreading member 354 is located on one side of the forming cylinder 21 and near the outlet of the powder bin, and the other powder spreading member 354 is located on the opposite side of the forming cylinder 21 and near the inlet of the powder bin. Below the powder spreading member 354 near the outlet of the powder hopper is a powder pile in which the powder 4 delivered by the lifting unit 34 is gathered. When powder is spread, the second driving wheel 351 drives the second conveyor belt 353 to rotate for half a circle anticlockwise, the powder spreading component 354 close to the outlet of the powder bin moves in a downward extending posture along the direction from the outlet to the inlet of the powder bin 31, pushes the powder pile on the top plate 12 to pass through the upper opening of the forming cylinder 21 at a constant speed from one side to the other side of the forming cylinder 21, and spreads the powder 4 on the printing substrate 23. The remaining powder 4 is then pushed into the inlet of the powder hopper 31 by the powder spreading member 354, completing a powder spreading cycle. During this time, the powder spreading member 354 near the inlet of the powder hopper is air-moved in an upwardly extending posture to the outlet near the powder hopper in the direction from the inlet to the outlet of the powder hopper 31. Before the next powder spreading period, the lifting unit 34 continues to convey the powder 4 to the top plate 12 to form a powder pile, the second driving wheel 351 drives the second conveying belt 353 to continue to rotate anticlockwise for half a circle, the powder spreading is started by the powder spreading component 354 which is moved to the powder bin outlet in an empty mode before, and the other powder spreading component 354 is moved to the powder bin outlet in an empty mode. The above process is repeated, and the two powder spreading elements 354 alternately spread powder.

In the illustrated embodiment, the powder spreading member 354 is configured in the form of a scraper, and during movement in the direction from the outlet to the inlet of the powder hopper 31, the top or top surface of the powder spreading member 354 abuts against the support surface of the support 1 for supporting the powder, preventing the powder 4 from remaining on the support 1. Although two powder spreading elements 354 are arranged at intervals in the illustrated embodiment and a powder spreading action is performed by one powder spreading element per powder spreading period, those skilled in the art will appreciate that the arrangement of the powder spreading elements is not limited thereto, and the number or configuration thereof may be changed as needed as long as it can function to push the powder on the bracket from the outlet of the powder hopper toward the inlet. For example, in an embodiment not shown, more than one, e.g., two or three, powder spreading elements are moved in sequence from the outlet to the inlet of the powder hopper for each powder spreading cycle, and the powder on the top plate is pushed one after another to perform the powder spreading action. The cooperation of multiple powder laying elements in the same powder laying cycle can further prevent powder residue on the stent. In another embodiment, not shown, the powder spreading element can be provided in a telescopic structure, and the extension length of the powder spreading element can be adaptively adjusted according to the distance between the powder spreading element and the supporting surface of the powder, so that the applicability and the powder pushing effect of the device are improved.

As shown in fig. 3, in some embodiments, a powder drop guide 36 may be disposed on the top plate 12 near the outlet of the powder bin 31, the powder drop guide 36 being located between the first driving wheel 341 and the second driving wheel 351 to receive the powders 4 sent by the bearing element 344 and guide the powders 4 onto the top plate 12. The powder fall guide plate 36 may be a wedge-shaped plate having a thickness on a side close to the first driving wheel 341 larger than that on a side away from the first driving wheel 341 so that the powder 4 poured out by the bearing member 344 may slide down along the surface of the powder fall guide plate 36 onto the top plate 12 and be aggregated into a powder pile at a predetermined position.

As shown in fig. 4, in the embodiment of the present invention, the controller 5 is connected to the lifting table 22, the first driving wheel 341 of the lifting unit 34, the agitator 32, the vibrator 33, and the second driving wheel 351 of the powder laying unit 35, respectively. The controller 5 sends an electric signal to the lifting table 22, and controls the lifting table 22 to drive the printing substrate 23 to move up and down and position in the forming cylinder 21 so as to adjust the powder spreading thickness. The controller 5 sends an electric signal to the lifting unit 34, and controls the lifting unit 34 to lift the powder 4 from the bottom of the powder hopper 31 to the upper surface of the top plate 12. The controller 5 sends an electric signal to the stirrer 32, and controls the stirrer 32 to slowly rotate at the bottom of the powder bin 31, so that the powder 4 keeps slowly flowing and uniformly distributed at the bottom of the powder bin 31. The controller 5 sends an electric signal to the vibrator 33 to drive the walls of the first vertical section 311 and the second vertical section 312 of the powder bin 31 to vibrate, so that powder cannot adhere to the walls of the first vertical section and the second vertical section, and the first vertical section and the second vertical section are prevented from being blocked. The controller 5 sends an electric signal to the powder spreading unit 35, and controls the powder spreading unit 35 to push the powder, which is sent to the top plate 12 by the lifting unit 34, to be spread on the printing substrate 23, and to push the remaining powder to the inlet of the powder bin 31.

A method of powder supply using the powder supply apparatus of the present invention will be described below with reference to fig. 5 to 12.

In some embodiments, a powder supply method according to the present invention comprises:

s100, the printing substrate 23 is moved to a predetermined position and positioned. This step can be performed by the controller 5 driving the movement of the lifting table. Wherein the predetermined position is a position lower than a supporting surface of the holder 1 for supporting the powder.

And S200, lifting the powder from the powder bin 31 to an outlet on one side of the printing substrate away from the powder bin, and accumulating the powder on a supporting surface. Wherein the lifting process can be performed by the bearing member 344 of the lifting unit 34, the bearing member 344 moves from the lower portion of the powder hopper 31 to a direction close to the outlet of the powder hopper 31 and feeds the powder 4 in the powder hopper 31 onto the supporting surface of the top plate 12. This step may be accomplished by the controller 5 driving the first driving pulley 341 of the lifting unit 34.

And S300, pushing the accumulated powder along the direction from one side of the printing substrate to the other opposite side so that at least part of the powder is paved on the printing substrate. Pushing the powder may be performed by the powder laying member 354. In accordance with the illustrated embodiment, in this process, one of the two powder laying members 354 of the powder laying unit 35 is moved from the outlet to the inlet of the powder hopper, pushing the powder on the top plate 12 to be laid on the print substrate 23. This step can be accomplished by the controller 5 driving the second driving wheel 351 of the powder laying unit 35.

And S400, continuously pushing the residual powder in the direction from one side of the printing substrate to the other side until the powder falls into an inlet of the powder bin at the other side of the printing substrate. In accordance with the illustrated embodiment, in this process, the powder spreading element is moved further and pushes the rest of the powder not spread on the print substrate 23 into the inlet of the powder hopper 31.

In some embodiments, the step of issuing a close command to the lifting unit 34 by the controller 5 may be performed before performing step S100.

In some embodiments, step S100 comprises the steps of:

s110, the controller 5 sends an initialization command to the lifting stage 22.

S120, the controller 5 controls the lifting stage 22 to drive the printing substrate 23 to ascend.

S130, when the height difference between the upper surface of the print substrate 23 and the supporting surface of the top plate 12 for supporting the powder is a predetermined single-layer powder-laying thickness, the print substrate 23 is positioned.

In some embodiments, referring to fig. 5 to 7, step S200 includes the steps of:

s210, the controller 5 sends a jog command to the lifting unit 34 to control the lifting unit to operate for a short time according to the set time.

S220, the carrying member 344 of the lifting unit 34 is controlled to lift the powder 4 upward from the bottom of the powder hopper 31.

S230, after the carrying element 344 turns around the highest point of the first driving wheel 341, the carried powder 4 is discharged by gravity, so that the powder 4 is gathered into a powder pile on the bracket 1.

In some embodiments, a step of injecting the powder 4 into the inlet of the second vertical section 312 of the powder hopper 31 may be further included before the step S210.

In some embodiments, before step S210, or during implementation of steps S210 to S230, any of the following steps may also be performed:

s2, the controller 5 issues an open command to the agitator 32.

S3, the controller 5 issues an on command to the vibrator 33.

In some embodiments, referring to fig. 8 to 12, step S300 includes the steps of:

s310, the controller 5 sends a start instruction to the powder spreading unit 35, and controls the second driving wheel 351 of the powder spreading unit 35 to rotate counterclockwise, for example, for a half-cycle, so as to drive the second conveyor and the two powder spreading components to move together, and prepare to start powder spreading (as shown in fig. 8).

S320, one of the two powder spreading members 354 moves with the second conveyor belt to turn downward and is located at one end of the powder spreading unit 35 near the outlet of the powder bin to approach the powder pile piled on the bracket 1 in a posture of protruding toward the bracket 1, while the other of the two powder spreading members 354 moves with the second conveyor belt to turn upward and is located at the other end of the powder spreading unit 35 in a posture of protruding away from the bracket 1 (as shown in fig. 9).

S330, the second driving wheel 351 continues to rotate counterclockwise, driving the powder spreading element 354 close to the outlet of the powder bin to move in the direction from the outlet to the inlet of the powder bin, pushing the powder pile through the first opening 121 of the top plate 12 at a constant speed and spreading on the printing substrate 23, and simultaneously driving the other powder spreading element 354 to move in the direction from the inlet to the outlet of the powder bin (as shown in fig. 10).

In some embodiments, step S400 includes the steps of:

s410, the controller 5 controls the second driving wheel 351 to rotate counterclockwise, drives the powder laying member 354 which has passed through the first opening 121 to move continuously and push the remaining powder into the inlet of the powder hopper, and simultaneously drives the other powder laying member 354 to move continuously to empty close to the outlet of the powder hopper (as shown in fig. 11).

S420, the second driving wheel 351 continues to rotate counterclockwise, and drives the powder spreading element 354 passing through the powder bin inlet to move along with the second conveyor belt to turn upward and be located at the end of the powder spreading unit 35 close to the powder bin inlet in a posture extending away from the bracket 1, while the other powder spreading element 354 moves along with the second conveyor belt to turn downward and be located at one end of the powder spreading unit 35 close to the powder bin outlet in a posture extending toward the top plate 12 (as shown in fig. 12).

Since the top of the powder spreading member is flush or attached to the upper surface of the top plate 12, a uniform thin layer of powder having an upper surface flush with the upper surface of the top plate 12 of the stand 1 and a thickness of a single layer of powder spreading thickness is formed on the print substrate 23 after the powder spreading member pushes the powder through the upper opening area of the forming cylinder.

After step S400, the operation of step S200 may be repeatedly performed to prepare for the next powdering cycle.

After step S400, the operation of step S100 may be performed again to drive the printed substrate to descend by a height corresponding to the single-layer powder spreading thickness, leaving a reserved powder spreading space on the last powder spreading plane.

In some embodiments, the step of sending an initialization instruction to the powder laying unit 35 by the controller 5 may also be performed before the step S310.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A powder supply apparatus for a powder bed, comprising:

a support;

the forming mechanism is arranged on the support and comprises a forming cylinder with an inner cavity and a lifting platform which can move in the inner cavity of the forming cylinder, and the lifting platform supports a printing substrate; and

supply powder mechanism, set up on the support and including powder storehouse, lifting unit and shop's powder unit, wherein the powder storehouse has the inner chamber and is linked together and is located respectively rather than the inner chamber the entry and the export of printing the relative both sides of base plate, the lifting unit has in the inner chamber can remove in order to send out the powder the carrier element in powder storehouse, shop's powder unit has can follow the export to the entry removes the shop's powder component with the powder that the propelling movement was sent out.

2. Powder supply device according to claim 1, wherein the side of the printing substrate forms a sliding sealing fit with the inner wall of the forming cylinder.

3. The powder supplying apparatus according to claim 1 or 2, wherein the lifting unit includes:

a first drive wheel disposed on the support corresponding to the outlet;

a first driven wheel arranged in the powder bin; and

the first transmission belt is sleeved on the first driving wheel and the first driven wheel;

wherein a plurality of carrier elements are spaced apart on the first conveyor belt, each carrier element being configured to be reversible upon exiting the outlet to deliver powder onto the support.

4. The powder supplying device according to claim 3, wherein the powder laying unit includes:

a second drive wheel disposed adjacent the outlet;

a second driven wheel disposed adjacent the inlet; and

the second conveying belt is sleeved on the second driving wheel and the second driven wheel and stretches across the printing substrate;

wherein the powder spreading member is disposed on the second conveyor belt and configured such that a top thereof abuts a top surface of the holder during movement from the outlet to the inlet.

5. Powder supply device according to claim 4, wherein a powder drop guide is provided on the carrier, which is located between the first drive wheel and the second drive wheel for guiding the powder fed out by the carrier element onto the carrier, the powder drop guide being configured such that the thickness of the side close to the first drive wheel is greater than the thickness of the side close to the second drive wheel.

6. The powder supplying device according to claim 3, wherein the powder hopper includes:

a first vertical section and a second vertical section arranged in opposition, wherein the first vertical section defines the outlet and the second vertical section defines the inlet; and

the transverse section is connected between the first vertical section and the second vertical section, and the transverse section, together with the first vertical section and the second vertical section, defines an inner cavity of the powder bin;

wherein the forming cylinder is located in a concave space defined by the first vertical section, the second vertical section, and the transverse section, and the first driven wheel is disposed in the first vertical section.

7. The powder supplying apparatus according to claim 6, wherein the elevating platform comprises an elevating rod movably provided on a lateral section of the powder hopper, a top portion of the elevating rod protruding into the inner cavity of the powder hopper, the elevating platform being provided on a top portion of the elevating rod.

8. The powder supplying apparatus according to claim 1 or 2,

a stirrer is arranged in the inner cavity of the powder bin; and/or

And a vibrator is arranged on the wall of the powder bin.

9. A powder supply method for a powder bed, characterized by comprising:

moving the printing substrate to a preset position and positioning;

lifting the powder from the powder bin to an outlet on one side of the printing substrate away from the powder bin and accumulating the powder on a supporting surface;

pushing the accumulated powder in a direction from the one side to the opposite side of the printing substrate so that at least a part of the powder is laid on the printing substrate;

pushing the remaining powder in the direction continues until it falls into the inlet of the powder bin on the other side of the print substrate.

10. The powder supplying method according to claim 9, wherein the powder on the supporting surface is pushed by a powder spreading member movable between an outlet and an inlet of the powder hopper, the powder spreading member being configured such that a top thereof abuts the supporting surface during movement from the outlet to the inlet;

moving and positioning the print substrate to a predetermined position includes: and moving the printing substrate to be positioned when the height difference between the top surface of the printing substrate and the supporting surface is the single-layer powder spreading thickness.