3D Printing Powder Spreading Device, Equipment and Method

Abstract

The present invention provides a 3D printing powder spreading device, equipment and method. By driving the powder bin to move, a part of the powder is caused to overflow from the powder bin. The powder overflowing from the powder bin is conveyed to a vibrating screen by a first powder spreading part, and the powder entering the vibrating screen is vibration-screened by the vibration of the vibrating screen at a certain frequency, so as to break up the powder and make it more loose. Then, a plasma mechanism releases plasma to the powder screened out from the vibrating screen to remove the static electricity of the powder itself. At the same time, the high-pressure plasma environment can quickly melt and spheroidize the raised burrs on the surface of the ultrafine powder particles. The melted and spheroidized ultrafine powder scatters on the forming platform, so as to evenly lay the treated powder on the forming platform. In this way, the ultrafine powder can be evenly and completely laid on the forming platform, so as to form parts with higher forming accuracy.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing, and particularly to a 3D printing powder spreading device, equipment and method thereof. Background Art

[0002] When constructing parts by 3D printing, the parts are often sliced into several two-dimensional planar structures, and then the parts are finally formed by layer-by-layer printing. Especially for the powder spreading sintering / fusion technology, a layer of metal powder / non-metal powder is spread layer by layer, and then a selected area of the spread metal powder is sintered / melted by a heat source (usually a laser), so as to construct the structure of the part in this layer. By spreading powder layer by layer and then sintering / melting, the construction of the part is finally completed. In the current field of powder spreading 3D printing technology, it is usually required that the powder has good fluidity and appropriate particle size to ensure the integrity and uniformity of powder spreading. Therefore, it is usually required that the powder particles to be spread have better sphericity and uniform particle size. However, the powder particle size of traditional powder spreading 3D printing is relatively large, which is not conducive to forming high-precision parts, resulting in poor surface roughness of 3D printed parts. If the powder particle size is further reduced and ultrafine powder is used for spreading, since the surface area of the powder layer formed by the ultrafine powder increases sharply, the powder will agglomerate, seriously affecting the uniformity and integrity of powder spreading. Summary of the Invention

[0003] In order to avoid the agglomeration of ultrafine powder and make the ultrafine powder evenly distributed on the forming platform, one aspect of the present invention provides a 3D printing powder spreading device, including: a powder bin for storing powder used for 3D printing; wherein the powder bin can cause a part of the powder to overflow from the powder bin under the action of a driving device; a first powder spreading part for conveying the powder overflowing from the powder bin in a direction away from the powder bin; at least one vibrating screen arranged in the direction of powder conveyance by the first powder spreading part, for receiving the powder conveyed by the first powder spreading part and vibrating and screening it to achieve loosening treatment of the powder; a plasma mechanism arranged in the separating direction of the powder after being screened by the vibrating screen, the plasma mechanism being composed of a powder falling channel and at least one plasma generator arranged on the powder falling channel; wherein the powder separated after being screened by the vibrating screen enters the powder falling channel, and the plasma generator is used to release plasma to the powder entering the powder falling channel to perform electrostatic elimination and / or burr melting treatment on the powder; and a forming platform arranged in the separating direction of the powder after being processed by the plasma mechanism, for receiving the powder separated from the plasma mechanism; wherein the powder is evenly spread on the forming platform.

[0004] Preferably, the 3D printing powder spreading device further includes a second powder spreading part for performing preliminary loosening treatment by rolling on the powder entering the vibrating screen.

[0005] Preferably, the second powder spreading part is a roller, and a plurality of protruding parts and recessed parts are formed at intervals on the side surface of the roller; the distance between the highest point of the protruding part and the lowest point of the recessed part is 50-300 μm.

[0006] Preferably, the vibrating screen is a trough-shaped screen and / or a hole-shaped screen.

[0007] Preferably, the trough-shaped screen has a plurality of powder screening troughs arranged at intervals, and the powder screening troughs extend from one end of the trough-shaped screen parallel to the powder conveying direction of the first powder spreading part to the other end.

[0008] Preferably, in the powder conveying direction of the first powder spreading part, the trough width of the powder screening trough gradually increases; the trough width increases from at least 0.2 mm to 2 mm.

[0009] Preferably, the hole-shaped screen has a plurality of powder screening holes arranged at intervals; the aperture of the powder screening holes is 10-30 μm.

[0010] Preferably, two vibrating screens are provided, one is the trough-shaped screen and the other is the hole-shaped screen; one vibrating screen is arranged in the separation direction of the powder after being screened by the other vibrating screen.

[0011] Preferably, the 3D printing powder spreading device further includes an ultrasonic mechanism for generating ultrasonic waves to perform preliminary loosening treatment on the powder entering the vibrating screen.

[0012] Preferably, the motion state of the plasma mechanism in three-dimensional space is in a moving state or a stationary state.

[0013] Preferably, in the moving state, the plasma mechanism lays the powder separated after being processed by the plasma mechanism on the forming platform according to a preset layer thickness.

[0014] Preferably, the 3D printing powder spreading device further includes a ranging sensor for obtaining the thickness of the laid powder layer by measuring the difference between the distance of the upper powder layer from the standard position and the distance of the currently laid powder layer from the standard position.

[0015] Preferably, the motion states of the plasma mechanism, the powder bin and the vibrating screen in three-dimensional space are synchronized.

[0016] Preferably, the 3D printing powder spreading device further includes a third powder spreading part for further spreading the powder laid on the forming platform.

[0017] Preferably, the third powder spreading part is a roller, and the roller moves along the powder spreading direction and / or in the opposite direction of the powder spreading direction to control the thickness and / or uniformity of the powder laid on the forming platform.

[0018] Preferably, when the motion state of the plasma mechanism is in a moving state in three-dimensional space, the motion states of the third powder spreading part, the powder bin, the vibrating screen, and the plasma mechanism are synchronized.

[0019] Preferably, the motion of the third powder spreading part is driven and controlled by a separate power source.

[0020] Preferably, the third powder spreading part has a heating unit for heating the surface of the third powder spreading part to transfer heat to the powder laid on the forming platform.

[0021] Preferably, the 3D printing powder spreading device further includes a heating device disposed above the forming platform for heating the powder laid on the forming platform in the form of thermal radiation.

[0022] Preferably, the vibration frequency of the vibrating screen is 500 - 3000 Hz.

[0023] In order to avoid the agglomeration of ultrafine powder and achieve a uniform distribution of the ultrafine powder on the forming platform, in one aspect of the present invention, a 3D printing device is provided, and the 3D printing device includes a structure for installing the aforementioned 3D printing powder spreading device on the 3D printing device.

[0024] In order to avoid the agglomeration of ultrafine powder and achieve a uniform distribution of the ultrafine powder on the forming platform, in one aspect of the present invention, a 3D printing powder spreading method is provided, including: driving a powder bin storing powder for 3D printing to move to cause a part of the powder to overflow from the powder bin; using a first powder spreading part to convey the powder overflowing from the powder bin in a direction away from the powder bin; using a plasma mechanism to release plasma to the powder separated after being conveyed by the first powder spreading part for electrostatic elimination and / or burr melting treatment of the powder; and using a forming platform to receive the powder separated from the plasma mechanism; wherein the powder is uniformly laid on the forming platform.

[0025] Preferably, before using a plasma mechanism to release plasma to the powder separated after being conveyed by the first powder spreading part for electrostatic elimination and / or burr melting treatment of the powder, the method further includes: using a vibrating screen to receive the powder conveyed by the first powder spreading part and performing vibrating screening on it to achieve loosening treatment of the powder.

[0026] Preferably, the method further includes: using a second powder spreading part to perform a preliminary loosening treatment of rolling and pressing on the powder entering the vibrating screen.

[0027] Preferably, the vibrating screen is a trough-shaped screen and / or a perforated screen; wherein, a vibrating screen is used to receive the powder conveyed by the first powder spreading part and perform vibrating screening on it to achieve loosening treatment of the powder, including: using the trough-shaped screen to receive the powder conveyed by the first powder spreading part and perform vibrating screening on it to achieve primary loosening treatment of the powder; and using the perforated screen to receive the powder separated after screening by the trough-shaped screen and perform vibrating screening on it to achieve secondary loosening treatment of the powder.

[0028] Preferably, the method further includes: using an ultrasonic mechanism to generate ultrasonic waves to perform preliminary loosening treatment on the powder entering the vibrating screen.

[0029] Preferably, the method further includes: controlling the plasma mechanism to move in three-dimensional space so that the powder separated after being processed by the plasma mechanism is laid on the forming platform according to a preset layer thickness.

[0030] Preferably, the method further includes: using a distance measuring sensor to measure the distance between the upper powder layer and the standard position and the distance between the currently laid powder layer and the standard position, and calculating the difference between the two to obtain the thickness of the laid powder layer.

[0031] Preferably, the method further includes: using a third powder spreading part to further spread the powder laid on the forming platform, specifically: controlling the third powder spreading part to move along the powder spreading direction and / or the opposite direction of the powder spreading direction to control the thickness and / or uniformity of the powder laid on the forming platform.

[0032] Preferably, the method further includes: using a heating unit to heat the surface of the third powder spreading part to transfer heat to the powder laid on the forming platform.

[0033] Preferably, the method further includes: using a heating device to heat the powder laid on the forming platform in the form of thermal radiation.

[0034] In the present invention, the powder bin is driven to move to cause a part of the powder to overflow from the powder bin. The powder overflowing from the powder bin is conveyed away from the powder bin by the first powder spreading part. Then, the plasma mechanism releases plasma to the powder separated after being conveyed by the first powder spreading part to remove the static electricity of the powder itself. At the same time, the high-pressure plasma environment can quickly melt and spheroidize the protrusions and burrs on the surface of the ultrafine powder particles. The melted and spheroidized ultrafine powder scatters on the forming platform, so that the processed powder is evenly laid on the forming platform. In this way, the 3D printing powder spreading device of the present invention can evenly and completely lay the ultrafine powder on the forming platform, so as to form parts with higher forming accuracy.

[0035] Furthermore, the present invention also arranges a vibrating screen in the direction of powder conveying by the first powder spreading part to receive the powder conveyed by the first powder spreading part and perform vibrating screening on it, thereby dispersing the powder and making it looser. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0037] Figure 1 The figure shows a schematic diagram before powder spreading of a 3D printing powder spreading device provided by one embodiment of the present invention;

[0038] Figure 2 The figure shows a schematic diagram after powder spreading of a 3D printing powder spreading device provided by one embodiment of the present invention;

[0039] Figure 3 The figure shows a schematic diagram of the movement of the powder bin relative to the vibrating screen along the X-axis provided by one embodiment of the present invention;

[0040] Figure 4 The figure shows a schematic diagram of the movement of the vibrating screen relative to the plasma mechanism along the Y-axis provided by one embodiment of the present invention;

[0041] Figure 5 The figure shows a schematic diagram of the arrangement of the third powder spreading part provided by one embodiment of the present invention;

[0042] Figure 6 The figure shows a schematic diagram of the arrangement of the third powder spreading part provided by another embodiment of the present invention;

[0043] Figure 7 The figure shows a schematic diagram of the arrangement of the second powder spreading part provided by one embodiment of the present invention;

[0044] Figure 8 The figure shows a schematic diagram of the structure of the second powder spreading part provided by one embodiment of the present invention;

[0045] Figure 9 The figure shows a schematic diagram of the arrangement of the ultrasonic mechanism provided by one embodiment of the present invention;

[0046] Figure 10 The figure shows a schematic diagram of the arrangement of two vibrating screens provided by one embodiment of the present invention;

[0047] Figure 11 The figure shows a surface schematic diagram of the trough-shaped screen provided by one embodiment of the present invention;

[0048] Figure 12 Shown is a schematic diagram of the surface of a hole-shaped sieve provided by one embodiment of the present invention;

[0049] Figure 13 Shown is a schematic diagram of the setting of a heating device provided by one embodiment of the present invention;

[0050] Figure 14 Shown is a schematic diagram of the setting of the mechanical unit of a 3D printing device provided by one embodiment of the present invention;

[0051] Figure 15 Shown is a schematic diagram of the movement trajectories of a powder spreading mechanism, a forming chamber, and an optical path unit provided by one embodiment of the present invention;

[0052] Figure 16 Shown is a schematic diagram of the movement trajectories of a powder spreading mechanism, a forming chamber, and an optical path unit provided by another embodiment of the present invention;

[0053] Figure 17 Shown is a schematic diagram of the movement trajectories of a powder spreading mechanism, a forming chamber, and an optical path unit provided by another embodiment of the present invention;

[0054] Figure 18 Shown is a schematic diagram of the process flow of a 3D printing powder spreading method provided by one embodiment of the present invention;

[0055] Figure 19 Shown is a schematic diagram of the process flow of a 3D printing powder spreading method provided by one embodiment of the present invention;

[0056] Figure 20 (a) shows a schematic diagram of the powder cluster phenomenon, (b) shows a schematic diagram of the ordinary powder spreading effect, and (c) shows a schematic diagram of the powder spreading effect of the present invention. Detailed Description of the Specific Embodiment

[0057] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0058] The 3D printing powder spreading device provided according to one aspect of the present invention is used for 3D printing equipment, that is, it can be used as a part of the 3D printing equipment structure. The 3D printing equipment described here is preferably a 3D printing category that uses a laser beam / electron beam as an energy source, such as Selective Laser Sintering (SLS), Selective Laser Melting (SLM), etc. All powder bed-based 3D printing technologies require pre-spreading of powder. Through laser scanning, the material is melted, and the loose powder is solidified together. By scanning layer by layer and spreading powder layer by layer, the retractable platform sinks, and finally a solid entity wrapped in powder is obtained.

[0059] In terms of components, the 3D printing equipment is at least composed of several parts such as a mechanical unit, an optical path unit, and a computer control system. The 3D printing powder spreading device of the present invention is preferably used as a part of the mechanical unit. Of course, it can also be used as a part independent of the mechanical unit, the optical path unit, and the computer control system. In a specific spatial layout form, the optical path unit can be arranged above the mechanical unit, or it can be set based on the core inventive points taught in this application according to the actual structural design. In the control logic, the computer control system realizes the control of the mechanical unit and the optical path unit, that is, the control of the 3D printing powder spreading device of the present invention is preferably realized by the computer control system.

[0060] Refer to Figure 1 , as shown in FIG. 2, in some embodiments, the 3D printing powder spreading device of the present invention is at least composed of a powder bin 10, a first powder spreading part 11, a vibrating screen 12, a plasma mechanism 13, a forming platform 14, etc.

[0061] Among them, the powder bin 10 is used to store the powder for 3D printing. The powder described here refers to the material to be processed and is used in a powder state. For example, the powder can mainly be composed of materials made of metal or polymer. And the powder described specifically refers to ultrafine powder. Of course, it can also be preferably applied in non-ultrafine powder. The particle size of the ultrafine powder described is usually less than 20 μm.

[0062] The powder bin 10 can cause a part of the powder to overflow from the powder bin 10 under the action of the driving device. In one embodiment, the driving device is a powder supply lifting device 101, that is, the powder bin 10 is driven to lift by the powder supply lifting device 101. When the powder supply lifting device 101 drives the powder bin 10 to rise, it can cause a part of the powder stored in the powder bin 10 to overflow from the powder bin 10. It should be understood that here only the powder supply lifting device 101 drives the piston in the powder bin 101 to move the piston upward for powder spreading is taken as an example. In another embodiment, the powder can also be fed upward, so that the first powder spreading part 11 can convey the powder in a direction away from the powder bin 101. Specifically, a powder dropping mechanism (not shown) is used for the upward powder feeding method. The powder dropping mechanism can, under the drive of the driving device, continuously scatter the powder at the front end of the moving direction of the first powder spreading part 11 through the powder dropping port. These scattered powders are conveyed in a direction away from the powder bin 101 under the action of the first powder spreading part 11.

[0063] Among them, the first powder spreading part 11 is arranged above the powder bin 10. It can move along the X-axis above the powder bin 10 and, based on the movement above the powder bin 10, convey the powder overflowing from the powder bin 10 in a direction away from the powder bin 10, specifically convey it into the vibrating screen 12. The specific form of the first powder spreading part 11 can be one of a powder spreading brush, a powder spreading roller, and a scraper. The present invention preferably uses a scraper.

[0064] Among them, the vibrating screen 12 is arranged in the direction of the powder conveyed by the first powder spreading part 11, and can also be understood as being arranged on the side adjacent to the powder bin 10, such as the left or right side of the powder bin 10. The vibrating screen 12 can receive the powder overflowing from the powder bin 10 conveyed by the first powder spreading part 11 and perform vibrating screening on it to achieve the loosening treatment of the powder. The vibration frequency of the vibrating screen 12 is set to 500 - 3000 Hz, preferably set to 500 Hz. It should be understood that the described vibrating screen 12 is composed of a screen body and a vibrating device (such as a vibrating motor) capable of exciting and driving the screen body to vibrate in practical applications.

[0065] Among them, the plasma mechanism 13 is arranged in the separation direction of the powder after being sieved by the vibrating screen 12, which can also be understood as being arranged below the vibrating screen 12 and on the side adjacent to the powder bin 10. The plasma mechanism 13 is used to release plasma to the powder sieved out from the vibrating screen 12 for static electricity elimination and / or burr melting treatment of the powder. The plasma mechanism 13 is composed of a powder falling channel 131 and a plasma generator 132 arranged on the powder falling channel 131; the powder separated after being sieved by the vibrating screen 12 enters the powder falling channel 131; the plasma generator 132 releases plasma to the powder entering the powder falling channel 131 for static electricity elimination and / or burr melting treatment of the powder. In one implementation manner, there are two plasma generators 132 which are arranged symmetrically at intervals, and the intermediate interval area forms the powder falling channel 131. In another implementation manner, the powder falling channel 131 is arranged as a shell with openings at both the top and the bottom, and the plasma generator 132 is arranged along the circumferential direction of the powder falling channel 131.

[0066] Among them, the forming platform 14 is arranged in the separation direction of the powder after being processed by the plasma mechanism 13, and is used to receive the powder separated from the plasma mechanism 13; the powder is evenly laid on the forming platform 14.

[0067] In the traditional 3D printing powder spreading process, the powder overflowing from the powder bin is directly moved and flattened on the forming platform by a scraper to form a layer of powder for part forming, and then a heat source such as a laser scans the powder layer along a certain path, and finally a cross-sectional structure of the part is formed. However, in the context of ultra-fine powder spreading proposed in this application, due to reasons such as agglomeration, it is difficult for ultra-fine powder to complete a uniform and complete powder layer on the forming platform under the action of the scraper.

[0068] And for the 3D printing powder spreading device composed of the above components (powder bin 10, first powder spreading part 11, vibrating screen 12, plasma mechanism 13 and forming platform 14) of the present invention, the first powder spreading part 11 conveys the powder overflowing from the powder bin 10 into the vibrating screen 12, and the vibrating screen 12 vibrates at a certain frequency to vibrate and sieve the powder entering the vibrating screen 12, so as to disperse the powder and make it looser. Then, the plasma mechanism 13 releases plasma to the powder sieved out from the vibrating screen 12 to remove the static electricity of the powder itself. At the same time, the high-pressure plasma environment can quickly melt and spheroidize the burrs on the surface of the ultra-fine powder particles. The melted and spheroidized ultra-fine powder scatters on the forming platform 14, so as to evenly lay the processed powder on the forming platform 14.

[0069] Optionally, in some embodiments, the 3D printing powder spreading device of the present invention is at least composed of a powder bin 10, a first powder spreading part 11, a plasma mechanism 13, a forming platform 14, etc. That is, the powder conveyed from the first powder spreading part 11 directly enters the plasma mechanism 13 without passing through the screening of the vibrating screen 12. In this setting, the plasma mechanism 13 is arranged in the separation direction of the powder after being conveyed by the first powder spreading part 11, and is used to release plasma to the powder for static electricity elimination and / or burr melting treatment of the powder. Specifically, the powder separated after being conveyed by the first powder spreading part 11 enters the powder falling channel 131; the plasma generator 132 is used to release plasma to the powder entering the powder falling channel 131 for static electricity elimination and / or burr melting treatment of the powder.

[0070] And for the 3D printing powder spreading device composed of the above components (powder bin 10, first powder spreading part 11, plasma mechanism 13 and forming platform 14) of the present invention, the powder overflowing from the powder bin 10 is conveyed to the plasma mechanism 13 by the first powder spreading part 11, and then the plasma mechanism 13 releases plasma to the powder to remove the static electricity of the powder itself. At the same time, the high-pressure plasma environment can quickly melt and spheroidize the raised burrs on the surface of the ultrafine powder particles. The melted and spheroidized ultrafine powder scatters on the forming platform 14, so as to evenly lay the treated powder on the forming platform 14.

[0071] Reference Figure 20 As shown, it can be seen from the figure that the ultrafine powder laid by the 3D printing powder spreading device of the present invention is very uniform on the forming platform 14.

[0072] In some embodiments, the motion state of the plasma mechanism 13 in three-dimensional space is in a moving state. Correspondingly, the motion state of the forming platform 14 in three-dimensional space is in a static state. In the three-dimensional space X-Y-Z, the plasma mechanism 13 can move relative to the forming platform 14 along the X-axis and / or Y-axis and / or Z-axis, so that the powder separated after being processed by the plasma mechanism 13 is laid on the forming platform 13 according to a preset layer thickness to complete uniform powder spreading for the forming platform 13.

[0073] This powder spreading method can spread powder on the forming platform 14 in a non-contact manner. That is to say, this non-contact powder spreading method can greatly reduce the damage to the formed component structure on the powder bed caused by traditional blade powder spreading. In some embodiments, for the powder laid in this way, during the forming process, a support structure does not need to be added to the cantilever structure of the formed part, or layer-by-layer printing can be realized.

[0074] Among them, the motion states of the plasma mechanism 13, the powder bin 10 and the vibrating screen 12 in three-dimensional space are synchronized, that is, their motion states in three-dimensional space are all in a moving state.

[0075] In one embodiment, the powder bin 10 is respectively connected to the plasma mechanism 13 and the vibrating screen 12, and is designed to be an integrally formed structure or a detachable structure that realizes the connection between the powder bin 10 and the plasma mechanism 13 and the vibrating screen 12 respectively through connecting members (such as bolts); in the connected state, a single driving mechanism shared by the three is used to realize the movement control of the whole formed by the combination of the three in three-dimensional space. In another embodiment, the powder bin 10, the plasma mechanism 13, and the vibrating screen 12 are separately arranged, and their respective driving mechanisms are used to realize synchronous or asynchronous driving control of their respective movement states, so as to realize the synchronous movement state of the powder bin 10, the plasma mechanism 13, and the vibrating screen 12 in three-dimensional space under synchronous driving control, and at least realize the movement of the plasma mechanism 13 relative to the forming platform 14 along the X-axis and / or Y-axis and / or Z-axis under asynchronous driving control. The present invention preferably uses the former, that is, the powder bin 10 is respectively connected to the plasma mechanism 13 and the vibrating screen 12, and a single driving mechanism shared by the three is used to realize the movement control of the whole formed by the combination of the three in three-dimensional space. On this basis, the movement state of the plasma mechanism 13 relative to the forming platform 14 can be understood as the movement state of the combination composed of the powder bin 10, the plasma mechanism 13, and the vibrating screen 12 relative to the forming platform 14.

[0076] When the powder bin 10, the plasma mechanism 13, and the vibrating screen 12 are separately arranged, and their respective driving mechanisms are used to realize asynchronous driving control of their respective movement states, referring to Figure 3 as shown, when the powder bin 10 overflows powder, it can be controlled by the corresponding driving mechanism to move in the direction (X-axis) of conveying powder along the first powder spreading part 11, so as to gradually approach the vibrating screen 12, and stop moving after contacting the vibrating screen 12, and then trigger the first powder spreading part 11 to perform the powder feeding work. Referring to Figure 4 as shown, when the vibrating screen 12 vibrates and screens the received powder, it can be controlled by the corresponding driving mechanism to move in the direction (Y-axis) of the powder separating from the vibrating screen 12 after screening, so as to gradually approach the plasma mechanism 13, so as to reduce the powder dropping distance between the vibrating screen 12 and the plasma mechanism 13.

[0077] In some embodiments, the 3D printing powder spreading device of the present invention further has a ranging sensor (not shown), which is used to obtain the thickness of the spread powder layer by measuring the difference between the distance of the upper powder layer from the standard position and the distance of the currently spread powder layer from the standard position after spreading. The standard position described here refers to the position where the ranging sensor is located. It should be understood that the thickness of the first powder layer is the difference between the distance from the upper surface of the forming platform 14 to the standard position and the distance from the first powder layer after spreading to the standard position. The ranging sensor can be any one of an ultrasonic ranging sensor, a laser ranging sensor, an infrared ranging sensor, and a millimeter-wave radar sensor.

[0078] Reference Figure 5 As shown in the reference, in some embodiments, the 3D printing powder spreading device of the present invention further has a third powder spreading part 17, which is used to further spread the powder laid on the forming platform 14. Among them, the specific form of the third powder spreading part 17 can be a roller, and the roller can move along the powder spreading direction and / or the opposite direction of the powder spreading direction to control the thickness and / or uniformity of the powder laid on the forming platform 14. Among them, when the movement state of the plasma mechanism 13 in the three-dimensional space is in a moving state, the movement state of the third powder spreading part 17 is synchronized with that of the powder bin 10, the vibrating screen 12, and the plasma mechanism 13, that is, the movement state in the three-dimensional space is also in a moving state, and it maintains a synchronous moving state with the powder bin 10, the vibrating screen 12, and the plasma mechanism 13. In order to achieve the synchronous moving state, in one embodiment, when the powder bin 10 is respectively connected to the plasma mechanism 13 and the vibrating screen 12 and the movement control of the whole formed by the three in the three-dimensional space is realized through a shared driving mechanism, the third powder spreading part 17 is connected to the powder bin 10 (integrally formed or detachably connected), for example, arranged at the lower right corner of the powder bin 10 as shown in Figure 5 shown. In the connected state, the third powder spreading part 17 can be driven by the powder bin 10 to achieve synchronous movement, or it can be understood that it can be driven by the combination formed by the powder bin 10, the plasma mechanism 13, and the vibrating screen 12 to achieve synchronous movement, so as to control the movement of the third powder spreading part 17 on the forming platform 14 along the powder spreading direction and / or the opposite direction of the powder spreading direction to control the thickness and / or uniformity of the powder laid on the forming platform 14.

[0079] Reference Figure 6As shown, in some embodiments, the movement of the third powder spreading unit 17 is driven and controlled by a separate power source. That is, the third powder spreading unit 17 is arranged on the forming platform 14, and is driven by a separate driving mechanism to move the third powder spreading unit 17 on the forming platform 14 along the powder spreading direction and / or the opposite direction of the powder spreading direction to control the thickness and / or uniformity of the powder laid on the forming platform 14. Among them, on the basis of driving and controlling the movement of the third powder spreading unit 17 by a separate power source, the movement states of the powder bin 10, the plasma mechanism 13 and the vibrating screen 12 in the three-dimensional space can be the aforementioned moving state or the stationary state. In the stationary state, after the powder falls off from the plasma mechanism 13, it scatters on the forming platform 14 in the form of free fall, and then the third powder spreading unit 17 is controlled to move on the forming platform 14 along the powder spreading direction and / or the opposite direction of the powder spreading direction for powder spreading.

[0080] In some embodiments, the third powder spreading unit 17 has a heating unit (not shown), for example, arranged inside the third powder spreading unit 17, so that when the third powder spreading unit 17 moves and spreads powder on the forming platform 17, the surface of the third powder spreading unit 17 can be heated to transfer heat to the powder laid on the forming platform 14, which is beneficial to the further dispersion of the powder.

[0081] Reference Figure 7 As shown, in some embodiments, the 3D printing powder spreading device of the present invention further has a second powder spreading unit 15, which is arranged in the vibrating screen 12 and can move along the powder spreading direction and / or the opposite direction of the powder spreading direction in the vibrating screen 12 to perform preliminary loosening treatment by rolling the powder entering the vibrating screen 12.

[0082] Reference Figure 8 As shown, among them, the specific form of the second powder spreading unit 15 can be a roller, and a plurality of convex portions 151 and concave portions 152 are formed at intervals on the side surface of the roller. The convex portions 151 and the concave portions 152 are preferably arranged at intervals. When rolling the vibrating screen 12, the side surface of the roller serves as the rolling surface. The distance between the highest point of the convex portion 151 and the lowest point of the concave portion 152 is set to be 50 - 300 μm. It should be understood that Figure 8 The sizes of the convex portion 151 and the concave portion 152 shown in are only for facilitating the understanding of their corresponding structures, and do not represent the dimensional ratios in their actual applications. By controlling the roller to roll the powder entering the vibrating screen 12, the ultrafine powder entering the vibrating screen 12 can be preliminarily loosened, and the agglomerated powder can be preliminarily loosened.

[0083] Reference Figure 9As shown, in some embodiments, the 3D printing powder spreading device of the present invention further has an ultrasonic mechanism 16, which is arranged above the vibrating sieve 12. The ultrasonic mechanism 16 may specifically be an ultrasonic generator, which can generate ultrasonic waves to perform ultrasonic vibration on the powder entering the vibrating sieve 12, so as to realize the preliminary loosening treatment of the powder in the vibrating sieve 12. It should be understood that in the embodiments of the present invention, the second powder spreading part 15 and the ultrasonic mechanism 16 can be used simultaneously to realize the preliminary loosening treatment of the powder in the vibrating sieve 12.

[0084] Reference Figure 11 As shown, in some embodiments, the vibrating sieve 12 is a trough-shaped sieve 12a. The trough-shaped sieve 12a has a plurality of powder screening troughs 121a arranged at intervals, and the powder screening troughs 121a extend from one end of the trough-shaped sieve 12a parallel to the powder conveying direction of the first powder spreading part 11 to the other end. In the powder conveying direction of the first powder spreading part 11, the trough width of the powder screening trough 121a gradually increases. For example, the trough width increases from at least 0.2 mm to 2 mm. It can be understood that the trough width of the powder screening trough 121a closest to the powder bin 10 is set to 0.2 mm, the trough width of the powder screening trough 121a farthest from the powder bin 10 is set to 2 mm, and the trough width of the powder screening troughs 121a in the middle is between 0.2 - 2 mm. Of course, this is only an example, and in actual applications, the variation range of the trough width can also be adaptively changed. For example, different variation ranges of the trough width can be set for ultrafine powders with different particle sizes. It should be understood that on the path of the first powder spreading part 11 conveying powder to the trough-shaped sieve 12a, the closer to the powder bin 10, the more powder is received. On the contrary, the farther from the powder bin 10, the less powder is received. In order to make the trough-shaped sieve 12a achieve relatively uniform powder screening, by gradually increasing the trough width, the powder screened from the trough-shaped sieve 12a can be made relatively uniform, which is convenient for subsequent laying.

[0085] Reference Figure 12 As shown, in some embodiments, the vibrating sieve 12 is a hole-shaped sieve 12b. The hole-shaped sieve 12b has a plurality of powder screening holes 121b arranged at intervals; the aperture of the powder screening holes 121b is 10 - 30 μm. Although Figure 12 the shape of the powder screening holes 121b shown in

[0086] is square, it should be understood that in actual applications, the powder screening holes 121b can also be presented in other shapes, such as round holes, and irregular polygon holes, etc., all within the protection scope of the present invention. Figure 11 , the sizes of the powder screening troughs 121a and the powder screening holes 121b shown in 12 respectively corresponding to the trough-shaped sieve 12a and the hole-shaped sieve 12b are only for facilitating the understanding of their corresponding structures, and do not represent the size ratios in their actual applications.

[0087] Reference Figure 10As shown, in some embodiments, two vibrating screens 12 are provided. Specifically, one of them can be set as a trough-shaped screen 12a and the other as a perforated screen 12b, or both can be set as trough-shaped screens 12a or perforated screens 12b. The present invention preferably adopts the former. In a specific spatial arrangement, one of the vibrating screens 12 is arranged in the separation direction of the powder after being screened by the other vibrating screen 12. For example, the perforated screen 12b is arranged in the separation direction of the powder after being screened by the trough-shaped screen 12a, that is, it can be understood that the perforated screen 12b is arranged below the trough-shaped screen 12a. After the trough-shaped screen 12a vibrates and screens the powder overflowing from the powder bin 10 conveyed by the first powder spreading part 11, the powder screened by the trough-shaped screen 12a enters the perforated screen 12b, and the perforated screen 12b then performs secondary vibration screening on the powder separated from the trough-shaped screen 12a to form two-stage powder screening, so as to achieve a better powder dispersion effect.

[0088] Reference Figure 13 As shown, in some embodiments, the 3D printing powder spreading device of the present invention further has a heating device 18, which is arranged above the forming platform 14 and is used to heat the powder laid on the forming platform 14 in the form of thermal radiation. In a specific spatial arrangement, for example, the heating device 18 is arranged between the forming platform 14 and the plasma mechanism 13, one end of the heating device 18 is connected to the powder bin 10, and the heating device 18 is arranged to be composed of a housing with openings at both the top and the bottom and heating components arranged circumferentially on the inner wall of the housing. The internal space of the housing forms a powder falling channel between the plasma mechanism 13 and the forming platform 14. The heating components can adopt, for example, infrared heating to achieve heating the powder laid on the forming platform 14 in the form of thermal radiation. In another specific spatial arrangement, for example, a separate driving mechanism is provided to move the heating device 18 from the side far away from the 3D printing powder spreading device of the present invention to above the forming platform 14 when the heating device 18 is needed to achieve heating the powder laid on the forming platform 14 in the form of thermal radiation.

[0089] Reference Figure 14As shown, on the one hand, the present invention provides a 3D printing device, which is composed of the aforementioned optical path unit, computer control system, and mechanical unit covering all or part of the structure of the 3D printing powder spreading device of the present invention. The mechanical unit also has a forming chamber 20, which is used for the construction of the formed part 23, that is, the formed part 23 completes the final construction in the forming chamber 20; the distance that the forming chamber 20 descends each time is the layer thickness; after the construction of the formed part 23 is completed, the forming chamber 20 rises to facilitate the removal of the constructed formed part 23 and prepare for the next construction. The lifting of the forming chamber 20 is driven by a forming lifting device 21. During the construction of the formed part 23, the powder is laid layer by layer above the forming chamber 23, that is, the forming platform 14, and then a powder bed 22 is formed above the forming platform 14. That is to say, the forming platform 14 of the 3D printing powder spreading device of the present invention is installed in the forming chamber 20. After the powder bed 22 is formed above the forming platform 14, the powder spreading described on the forming platform 14 also means powder spreading on the powder bed 22. It should also be understood that the described powder bin 10, plasma mechanism 13, and vibrating screen 12 are equivalent to the movement state of the forming platform 14, that is, equivalent to the movement state of the powder bed 22 / forming chamber 20.

[0090] Wherein, after the above powder spreading process of the present invention is completed, the next stage of work is carried out, that is, the optical path unit of the 3D printing device is enabled to act on the powder on the forming platform 14 to construct the formed part 23.

[0091] In some embodiments, a driving mechanism a is used to drive the combination of the powder bin 10, vibrating screen 12, and plasma mechanism 13 (named the powder spreading mechanism) to move in three-dimensional space, a driving mechanism b is used to drive the forming chamber 20 to move in three-dimensional space, and a driving mechanism c is used to drive the optical path unit to move in three-dimensional space.

[0092] Reference Figure 15 As shown, in a specific movement control trajectory, after at least one layer of powder spreading is completed, the driving mechanism a is used to control the powder spreading mechanism to move from the X1 area to the X2 area on the X-axis, then the driving mechanism c is used to control the optical path unit 30 to move from the Y1 area to the Y2 area on the Y-axis, and the driving mechanism b does not act, so that the forming chamber 20 remains in the initial position. Thereby, the optical path unit 30 is moved above the forming chamber 20 to act on the powder on the forming platform 14, so as to construct the formed part 23.

[0093] Reference Figure 16As shown, in a specific movement control trajectory, after at least one layer of powder spreading is completed, the driving mechanism b is commanded to control the forming chamber 20 to move from the X3 area to the X4 area on the X-axis, and the driving mechanisms b and c are both deactivated to keep the powder spreading mechanism and the optical path unit 30 in their initial positions. Thereby, the forming chamber 20 is moved below the optical path unit 30 so that the optical path unit 30 acts on the powder on the forming platform 14, thereby constructing the formed part 23.

[0094] Reference Figure 17 As shown, in a specific movement control trajectory, after at least one layer of powder spreading is completed, the driving mechanism a is commanded to control the powder spreading mechanism to move from the Y3 area to the Y4 area on the Y-axis, and then the driving mechanism c is commanded to control the optical path unit 30 to move from the X5 area to the X6 area on the X-axis, and the driving mechanism b is deactivated to keep the forming chamber 20 in its initial position. Thereby, the optical path unit 30 is moved above the forming chamber 20 to act on the powder on the forming platform 14, thereby constructing the formed part 23.

[0095] Wherein Figures 15 - 17 What is shown are all the movement trajectory controls on the X-axis / Y-axis. In more movement control trajectories, control can also be performed on the Z-axis, that is, the driving mechanisms a / b / c are respectively commanded to control the corresponding powder spreading mechanism / forming chamber 20 / optical path unit 30 to also move on the Z-axis, so as to move the optical path unit 30 above the forming chamber 20 to act on the powder on the forming platform 14, thereby constructing the formed part 23.

[0096] Reference Figures 1 - 20 As shown, on the one hand, the present invention provides a 3D printing powder spreading method.

[0097] Reference Figure 18 As shown, this method is at least composed of S101 - S105.

[0098] S101, driving a powder bin storing powder for 3D printing to rise to cause a part of the powder to overflow from the powder bin.

[0099] S102, using a first powder spreading part to convey the powder overflowing from the powder bin in a direction away from the powder bin.

[0100] S103, using a vibrating screen to receive the powder conveyed by the first powder spreading part and vibrating and screening it to achieve loosening treatment of the powder.

[0101] S104, using a plasma mechanism to release plasma to the powder screened out from the vibrating screen to perform electrostatic elimination and / or burr melting treatment on the powder. And

[0102] S105, receive the powder detached from the plasma mechanism by using a forming platform; wherein the powder is evenly laid on the forming platform.

[0103] Reference Figure 19 As shown, optionally, the method at least consists of S201 - S204.

[0104] S201, drive a powder bin storing powder for 3D printing to move so as to cause a part of the powder to overflow from the powder bin.

[0105] S202, use a first powder spreading part to convey the powder overflowing from the powder bin in a direction away from the powder bin.

[0106] S203, use a plasma mechanism to release plasma to the powder detached after being conveyed by the first powder spreading part so as to perform static elimination and / or burr melting treatment on the powder. And

[0107] S204, receive the powder detached from the plasma mechanism by using a forming platform; wherein the powder is evenly laid on the forming platform.

[0108] In some embodiments, the 3D printing powder spreading method of the present invention further includes: using a second powder spreading part to perform a preliminary loosening treatment of rolling the powder entering the vibrating screen.

[0109] In some embodiments, the vibrating screen is a trough - shaped screen and / or a hole - shaped screen; wherein S103 includes: using the trough - shaped screen to receive the powder conveyed by the first powder spreading part and performing vibrating screening on it to achieve a primary loosening treatment of the powder; and using the hole - shaped screen to receive the powder detached after being screened by the trough - shaped screen and performing vibrating screening on it to achieve a secondary loosening treatment of the powder.

[0110] In some embodiments, the 3D printing powder spreading method of the present invention further includes: using an ultrasonic mechanism to generate ultrasonic waves to perform a preliminary loosening treatment of vibrating the powder entering the vibrating screen.

[0111] In some embodiments, the 3D printing powder spreading method of the present invention further includes: controlling the plasma mechanism to move in three - dimensional space so that the powder detached after being processed by the plasma mechanism is laid on the forming platform according to a preset layer thickness.

[0112] In some embodiments, the 3D printing powder spreading method of the present invention further includes: using a ranging sensor to measure the distance between the upper powder layer and the standard position and the distance between the currently laid powder layer and the standard position, and calculating the difference between the two to obtain the thickness of the laid powder layer.

[0113] In some embodiments, the 3D printing powder spreading method of the present invention further includes: further spreading the powder laid on the forming platform by a third powder spreading part, specifically: controlling the third powder spreading part to move along the powder spreading direction and / or the opposite direction of the powder spreading direction to control the thickness and / or uniformity of the powder laid on the forming platform.

[0114] In some embodiments, the 3D printing powder spreading method of the present invention further includes: heating the surface of the third powder spreading part by a heating unit to transfer heat to the powder laid on the forming platform.

[0115] In some embodiments, the 3D printing powder spreading method of the present invention further includes: heating the powder laid on the forming platform by a heating device in the form of thermal radiation.

[0116] It should be understood that for the 3D printing powder spreading method provided by the present invention, the specific implementation process corresponds to the 3D printing powder spreading device provided by the present invention. Therefore, the implementation process of this method will not be elaborated herein.

[0117] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0118] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over", and "on" the second feature may be that the first feature is directly above or obliquely above the second feature, or simply means that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below", and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower horizontal height than the second feature.

[0119] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0120] Description of the reference numerals:

[0121] 10 Powder bin

[0122] 101 Powder supply lifting device

[0123] 11 First powder spreading part

[0124] 12 Vibrating screen

[0125] 12a Trough-shaped screen

[0126] 12b Hole-shaped screen

[0127] 121a Screen powder trough

[0128] 121b Screen powder holes

[0129] 13 Plasma mechanism

[0130] 131 Powder dropping channel

[0131] 132 Plasma generator

[0132] 14 Forming platform

[0133] 15 Second powder spreading part

[0134] 151 Protruding part

[0135] 152 Recessed part

[0136] 16 Ultrasonic mechanism

[0137] 17 Third powder spreading part

[0138] 18 Heating device

[0139] 20 Forming chamber

[0140] 21 Forming lifting device

[0141] 22 Powder bed

[0142] 23 Formed part

Claims

1. A 3D printing powder spreading device, characterized in that, it includes: a powder bin for storing the powder used for 3D printing; wherein the powder bin can cause a part of the powder to overflow from the powder bin under the action of a driving device; a first powder spreading part for conveying the powder overflowing from the powder bin in a direction away from the powder bin; at least one vibrating screen arranged in the conveying direction of the powder by the first powder spreading part, for receiving the powder conveyed by the first powder spreading part and vibrating and screening it to realize the loosening treatment of the powder; a plasma mechanism arranged in the separating direction of the powder after being screened by the vibrating screen, the plasma mechanism is composed of a powder falling channel and at least one plasma generator arranged on the powder falling channel; wherein the powder separated after being screened by the vibrating screen enters the powder falling channel, and the plasma generator is used to release plasma to the powder entering the powder falling channel to perform electrostatic elimination and / or burr melting treatment on the powder; and a forming platform arranged in the separating direction of the powder after being processed by the plasma mechanism, for receiving the powder separated from the plasma mechanism; wherein the powder is evenly laid on the forming platform.

2. The 3D printing powder spreading device according to claim 1, characterized in that, it further includes: a second powder spreading part for performing a preliminary loosening treatment of rolling pressure on the powder entering the vibrating screen.

3. The 3D printing powder spreading device according to claim 2, characterized in that, the second powder spreading part is a roller, and a plurality of convex parts and concave parts are formed at intervals on the side surface of the roller; wherein the distance between the highest point of the convex part and the lowest point of the concave part is 50 - 300 μm.

4. The 3D printing powder spreading device according to claim 1, characterized in that, the vibrating screen is a trough-shaped screen and / or a hole-shaped screen.

5. The 3D printing powder spreading device according to claim 4, characterized in that, the trough-shaped screen has a plurality of powder screening troughs arranged at intervals, wherein the powder screening troughs extend from one end of the trough-shaped screen parallel to the powder conveying direction of the first powder spreading part to the other end.

6. The 3D printing powder spreading device according to claim 5, characterized in that, in the powder conveying direction of the first powder spreading part, the trough width of the powder screening trough gradually increases; wherein the trough width increases from at least 0.2 mm to 2 mm.

7. The 3D printing powder spreading device according to claim 4, characterized in that, the hole-shaped screen has a plurality of powder screening holes arranged at intervals; wherein the aperture of the powder screening holes is 10 - 30 μm.

8. The 3D printing powder spreading device according to claim 4, characterized in that, two vibrating screens are provided, one is the trough-shaped screen and the other is the hole-shaped screen; one vibrating screen is arranged in the separating direction of the powder after being screened by the other vibrating screen.

9. The 3D printing powder spreading device according to claim 1, characterized in that, it further includes: an ultrasonic mechanism for generating ultrasonic waves to perform a preliminary loosening treatment of vibrating on the powder entering the vibrating screen.

10. The 3D printing powder spreading device according to claim 1, It is characterized in that the motion state of the plasma mechanism in three-dimensional space is a moving state or a stationary state.

11. The 3D printing powder spreading device according to claim 10, It is characterized in that when the plasma mechanism is in a moving state, the powder separated after being processed by the plasma mechanism is laid on the forming platform according to a preset layer thickness.

12. The 3D printing powder spreading device according to claim 10, It is characterized in that It further includes: a ranging sensor, which is used to obtain the thickness of the laid powder layer by measuring the difference between the distance of the upper powder layer from the standard position and the distance of the currently laid powder layer from the standard position.

13. The 3D printing powder spreading device according to claim 10, It is characterized in that the motion states of the plasma mechanism, the powder bin and the vibrating screen in three-dimensional space are synchronized.

14. The 3D printing powder spreading device according to claim 13, It is characterized in that It further includes: a third powder spreading part, which is used to further spread the powder laid on the forming platform.

15. The 3D printing powder spreading device according to claim 14, It is characterized in that the third powder spreading part is a roller, and the roller moves along the powder spreading direction and / or the opposite direction of the powder spreading direction to control the thickness and / or uniformity of the powder laid on the forming platform.

16. The 3D printing powder spreading device according to claim 14, It is characterized in that when the motion state of the plasma mechanism in three-dimensional space is a moving state, the motion states of the third powder spreading part, the powder bin, the vibrating screen and the plasma mechanism are synchronized.

17. The 3D printing powder spreading device according to claim 14, It is characterized in that the motion of the third powder spreading part is driven and controlled by a separate power source.

18. The 3D printing powder spreading device according to claim 14, It is characterized in that the third powder spreading part has a heating unit, which is used to heat the surface of the third powder spreading part to transfer heat to the powder laid on the forming platform.

19. The 3D printing powder spreading device according to claim 14, It is characterized in that It further includes: a heating device, which is arranged above the forming platform and is used to heat the powder laid on the forming platform in the form of thermal radiation.

20. The 3D printing powder spreading device according to claim 1, It is characterized in that the vibration frequency of the vibrating screen is 500 - 3000 Hz.

21. A 3D printing device, It is characterized in that the 3D printing device includes a structure for installing the 3D printing powder spreading device according to any one of claims 1 - 20 on the 3D printing device.

22. A 3D printing powder spreading method for the 3D printing powder spreading device according to any one of claims 1 - 20, It is characterized in that the method includes: driving a powder bin storing powder for 3D printing to move to cause a part of the powder to overflow from the powder bin; using a first powder spreading part to convey the powder overflowing from the powder bin in a direction away from the powder bin; Using a plasma mechanism to release plasma to the powder that has been conveyed by the first powder spreading unit and then separated, for the electrostatic elimination and / or burr melting treatment of the powder; and Using a forming platform to receive the powder separated from the plasma mechanism; wherein the powder is evenly spread on the forming platform.

23. The 3D printing powder spreading method according to claim 22, characterized in that before using a plasma mechanism to release plasma to the powder that has been conveyed by the first powder spreading unit and then separated, for the electrostatic elimination and / or burr melting treatment of the powder, the method further includes: Using a vibrating screen to receive the powder conveyed by the first powder spreading unit and vibrating and screening it to achieve the loosening treatment of the powder.

24. The 3D printing powder spreading method according to claim 23, characterized in that further includes: Using a second powder spreading unit to perform a preliminary loosening treatment by rolling the powder that enters the vibrating screen.

25. The 3D printing powder spreading method according to claim 23, characterized in that the vibrating screen is a trough-shaped screen and / or a hole-shaped screen; wherein, using a vibrating screen to receive the powder conveyed by the first powder spreading unit and vibrating and screening it to achieve the loosening treatment of the powder includes: Using the trough-shaped screen to receive the powder conveyed by the first powder spreading unit and vibrating and screening it to achieve the primary loosening treatment of the powder; and Using the hole-shaped screen to receive the powder separated after being screened by the trough-shaped screen and vibrating and screening it to achieve the secondary loosening treatment of the powder.

26. The 3D printing powder spreading method according to claim 23, characterized in that further includes: Using an ultrasonic mechanism to generate ultrasonic waves to perform a preliminary loosening treatment by vibrating the powder that enters the vibrating screen.

27. The 3D printing powder spreading method according to claim 23, characterized in that further includes: Controlling the plasma mechanism to move in three-dimensional space so that the powder separated after being processed by the plasma mechanism is laid on the forming platform according to a preset layer thickness.

28. The 3D printing powder spreading method according to claim 23 or 27, characterized in that further includes: Using a ranging sensor to measure the distance between the upper powder layer and the standard position and the distance between the currently laid powder layer and the standard position, and calculating the difference between the two to obtain the thickness of the laid powder layer.

29. The 3D printing powder spreading method according to claim 23 or 27, characterized in that further includes: Using a third powder spreading unit to further spread the powder laid on the forming platform, specifically: controlling the third powder spreading unit to move along the powder spreading direction and / or the opposite direction of the powder spreading direction to control the thickness and / or uniformity of the powder laid on the forming platform.

30. The 3D printing powder spreading method according to claim 29, characterized in that further includes: Using a heating unit to heat the surface of the third powder spreading unit to transfer heat to the powder laid on the forming platform.

31. The 3D printing powder spreading method according to claim 22, characterized in that further includes: A heating device is used to heat the powder laid on the forming platform in the form of thermal radiation.

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