Additive manufacturing method and device based on powder laying in multiple powder selective areas

Abstract

The invention relates to an additive manufacturing method and device based on powder laying in a multi-powder selective area, and the method comprises the steps: (1) building a three-dimensional model of a part, and slicing the three-dimensional model of the part; (2) paving the same or different powder materials at different positions on the upper surface of the substrate or the supporting piece according to the section pattern after slicing to form a powder layer; (3) spraying a layer of binder on at least part of the powder area laid in the step (2) and curing, and / or directly sintering at least part of the powder area by using an energy beam; (4) repeating the steps (2)-(3) to form a pre-printed workpiece; and (5) the pre-printed workpiece is put into a sintering furnace to be sintered, and a formed part is formed after the binder is volatilized. According to the method, part performance indexes which cannot be met by single powder can be achieved through mixed printing of multiple kinds of powder, meanwhile, screening of the multiple kinds of powder can be effectively achieved, the powder printing consumption cost is reduced, and the mixed printing efficiency of the multiple kinds of powder is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of additive manufacturing, and in particular relates to an additive manufacturing method and device based on multi-powder selective regional powder spreading. Background Art

[0002] Additive Manufacturing (AM) technology is a technology that uses the method of gradually accumulating materials to manufacture physical parts. Compared with traditional material removal-cutting processing technology, it is a "bottom-up" manufacturing method.

[0003] SLM, Selective laser melting, is a major technical approach in additive manufacturing of metal materials. This technology uses laser as the energy source and scans the metal powder bed layer by layer according to the path planned in the 3D CAD slice model. The scanned metal powder is melted and solidified to achieve the metallurgical bonding effect, and finally the metal parts designed by the model are obtained.

[0004] The existing metal additive manufacturing method usually uses a single metal powder material for SLM printing and molding. The problems with using a single metal powder material SLM printing and molding are: it cannot meet the different functional requirements of different areas of the molded parts. For example, some areas require high temperature resistance and need to be printed with high temperature resistant materials. Some areas require better thermal and electrical conductivity and need to be made of materials with better thermal or electrical conductivity. Some areas have higher requirements for strength and need to be printed with higher strength materials. On the other hand, when spreading powder in the existing additive manufacturing method, the entire substrate surface used for printing and molding needs to be spread with powder. The powder spreading area is large. Especially for large-format laser molding manufacturing, this powder spreading method will cause a large waste of powder and high cost. Summary of the invention

[0005] In order to solve the problems existing in the background technology, the present invention provides an additive manufacturing method based on multi-powder selective regional powder spreading. Through the mixed printing of multiple powders, not only can the part performance indicators that cannot be met by a single powder be achieved, but also the screening of multiple powders can be effectively realized, thereby reducing the printing powder consumption cost, improving the efficiency of mixed printing of multiple powders, simplifying the process flow, and ensuring the quality of the product.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In one aspect, the present invention provides an additive manufacturing method based on multi-powder selective regional powder spreading, comprising the steps of:

[0008] (1) Establish a three-dimensional model of the part and slice it;

[0009] (2) laying the same or different powder materials at different positions on the upper surface of the substrate or the support to form a powder layer according to the cross-sectional diagram after slicing and the corresponding powder requirements at different regional positions;

[0010] (3) spraying a layer of binder on at least part of the powder area laid in step (2) and curing it,

[0011] and / or directly sintering or melting at least a portion of the powder region using an energy beam;

[0012] The entire powder area and then the substrate is lowered to a preset height;

[0013] (4) Repeat steps (2) to (3) to form a pre-printed workpiece;

[0014] (5) placing the pre-printed workpiece into a sintering furnace for sintering, so that the binder is volatilized to form a molded part;

[0015] (6) Air-cool the molded part.

[0016] Preferably, the step (3) includes spraying a layer of binder on a part of the powder area in step (2) and curing it, and sintering and curing the remaining powder area by laser sintering, and the energy beam is a laser or an electron beam.

[0017] Preferably, the thickness of the powder layer is 0.01 mm to 0.2 mm.

[0018] Preferably, in step (2), laying the same or different powder materials at different positions on the upper surface of the substrate or the support to form a powder layer includes powdering and powdering. The powdering is specifically when the adsorption roller rotates through the powder outlet of the powder dropping trough, the electrostatically charged area automatically adsorbs the powder according to the shape of the area to be laid; the powdering is specifically when the adsorption roller adsorbs the powder and rotates to the position of the processing table, the static electricity on the adsorption roller is eliminated, and the powder is naturally laid on the processing table according to the programmed shape.

[0019] Preferably, the sintering temperature in step (5) is in the range of 500°C to 1500°C.

[0020] Preferably, the curing is performed using ultraviolet / infrared light.

[0021] The present invention also provides an additive manufacturing device for implementing the additive manufacturing method, comprising: a workbench base and a powder spreading mechanism, a binder spraying and curing mechanism, a sintering module, and a driving mechanism installed on the workbench base;

[0022] The substrate is fixed on the workbench base;

[0023] The powder spreading mechanism is used to spread different powder materials on different positions of the substrate or the support member according to needs;

[0024] The binder spraying and curing mechanism is used to spray a layer of binder onto the powder layer and perform curing;

[0025] The sintering module is located above the substrate and is used to sinter or melt the powder;

[0026] The driving mechanism is used to control the movement of the powder spreading mechanism and / or the binder spraying and curing mechanism.

[0027] Preferably, the powder spreading mechanism spreads the powder along the horizontal direction of the substrate, and the binder spraying and curing mechanism sprays the binder along the vertical direction of the substrate and cures the sprayed powder layer.

[0028] Preferably, the different powder materials include metal powder and non-metal powder.

[0029] Preferably, the powder spreading mechanism comprises a powder dropping groove and an adsorption roller, wherein the powder dropping groove comprises a plurality of powder dropping grooves, wherein different powder materials are contained in the plurality of powder dropping grooves, and the adsorption roller comprises a roller body, and a plurality of electrostatic generators uniformly arrayed in the circumferential direction and axial direction along the outer surface of the roller body;

[0030] When the adsorption roller rotates and passes the powder outlet of the powder drop trough, the electrostatically charged area automatically adsorbs the powder according to the shape of the area to be spread.

[0031] When the adsorption roller adsorbs the powder and rotates to the processing table, the static electricity on the adsorption roller is eliminated, and the powder is naturally spread on the processing table according to the programmed shape;

[0032] The powder spreading device further comprises a programmable controller, which is connected to the electrostatic generator and is used for controlling the electrostatic generators in different areas to charge or discharge according to a preset powder spreading shape.

[0033] The present invention adopts the above technical solution, which has the following advantages:

[0034] (1) The present invention provides an alternative printing method, that is, after laying two or more metal powders in each layer, the mixed printing of multiple powders can not only achieve part performance indicators that cannot be met by a single powder, but also effectively realize the screening of multiple powders, thereby reducing the cost of printing powders, improving the efficiency of mixed printing of multiple powders, simplifying the process flow, and ensuring the quality of the product.

[0035] (2) The present invention can also use a method of spraying a binder to bond and solidify part of the powder, and use a laser sintering method to solidify another main powder, and repeat this cycle to obtain a preformed component, and finally put the preformed component as a whole into a sintering furnace for sintering to obtain a molded component. Compared with the existing method that relies on laser sintering layer by layer, the present invention provides a method for selective regional powder spreading additive printing of multiple powders. Through the mixed printing of multiple powders, not only can the performance indicators of parts that cannot be met by a single powder be achieved, but also the screening of multiple powders can be effectively achieved, thereby reducing the cost of printing powders, improving the efficiency of mixed printing of multiple powders, simplifying the process flow, and ensuring the quality of the product.

[0036] (3) Compared with the existing technology that uses a single metal powder melting method, the present invention can select appropriate metal powders for molding according to the performance requirements of different parts of the parts through selective regional powder spreading, thereby improving the customizability of the parts. In addition, compared with the existing selective laser powder melting, powder can only be laid on the parts that need to be formed, avoiding the laying of powder on the entire substrate or support surface, which can effectively reduce the waste and loss of powder.

[0037] (4) Compared with the existing metal additive manufacturing method, it is impossible to mix metal powder and non-metal powder for printing. Even if it can be printed, there is still the problem that the metal powder and non-metal powder cannot be screened and recycled. The additive manufacturing device provided by the present invention is not limited to the additive manufacturing of metal powder, but can also be non-metallic powder materials, or a combination of metal powder and non-metallic powder, and there is no problem of needing to clean the powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Throughout the accompanying drawings, the same reference numerals are used to represent the same components. In the accompanying drawings:

[0039] Figure 1 It is a schematic diagram of the modularization of the additive manufacturing device based on multi-powder selective regional powder spreading provided by the present invention;

[0040] Figure 2 yes Figure 1 The main view of

[0041] Figure 3 It is a structural schematic diagram of the powder spreading mechanism;

[0042] Figure 4 yes Figure 3 The main view of

[0043] Figure 5 yes Figure 3 A top view of

[0044] Figure 6 It is a schematic diagram of the structure of the powder suction roller;

[0045] Figure 7 It is the cross-sectional view of the part to be printed;

[0046] Figure 8 It is a flow chart of the additive manufacturing method based on multi-powder selective regional powder spreading provided by the present invention.

[0047] The symbols in the accompanying drawings are as follows:

[0048] 1- workbench base, 2- substrate, 3- jetting and curing mechanism, 4- sintering module, 5- powder spreading mechanism, 6- driving mechanism, 51- powder dropping trough, 52- adsorption roller, 53- powder outlet, 521- electrostatic generator, 10- parts. DETAILED DESCRIPTION

[0049] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0050] like Figure 1 and Figure 2 As shown, one embodiment of the present invention provides an additive manufacturing device based on multi-powder selective regional powder spreading, the device includes a workbench base 1 and a powder spreading mechanism 5 installed on the workbench base 1, a binder injection and curing mechanism 3, a sintering module 4, and a driving mechanism 6.

[0051] The substrate 5 is fixed on the workbench base 1; the powder spreading mechanism 5 is used to spread different powder materials at different positions of the substrate 2 or the support as needed; the binder injection and curing mechanism 3 is used to spray a layer of binder on the powder layer and cure it; the sintering module 4 is located above the substrate 2 and is used to sinter or melt the powder; the driving mechanism 6 is used to control the movement of the powder spreading mechanism 5 and / or the binder injection and curing mechanism 3.

[0052] When performing additive manufacturing, the powder spreading mechanism 5 first spreads the powder according to the cross-sectional shape of the parts to be formed and the material requirements of different areas; after the powder spreading is completed, a layer of binder is sprayed on the laid powder layer and cured, and the substrate 2 is lowered to a preset height after spraying and curing; the steps of spreading the powder and spraying the binder are repeated to form a pre-printed workpiece; the pre-printed workpiece is placed in a sintering furnace (not shown in the figure) for sintering, and a molded part is formed after the binder volatilizes; after sintering, the molded part is air-cooled.

[0053] It should be noted that the preset height usually refers to the thickness of a powder layer.

[0054] It should be noted that the above-mentioned support member refers to the semi-finished product that has been printed previously.

[0055] The driving mechanism may be driven by an existing motor, or may be driven by a cylinder or hydraulic cylinder. In order to improve the accuracy of the movement, the driving mechanism is preferably driven by a motor in conjunction with a lead screw.

[0056] The powder spreading mechanism 5 and the binder spraying and curing mechanism 3 may share a driving component, or may be driven by different driving components respectively.

[0057] The present invention provides an alternative printing method, that is, after each layer of metal powder is laid, a layer of adhesive is sprayed for bonding and curing, and a preformed component is obtained by repeating this cycle. Finally, the preformed component is sintered as a whole to obtain a formed component. Compared with the existing method that relies on laser for layer-by-layer sintering, the present invention can not only improve printing efficiency and reduce costs, but also simplify the process flow and ensure product quality.

[0058] Combination Figures 3 to 6 As shown, the powder spreading mechanism 5 includes a powder dropping trough 51 and an adsorption roller 52, the adsorption roller 52 includes a roller body, a plurality of electrostatic generators 521 uniformly arrayed in the circumferential direction and along the outer surface of the roller body, the powder spreading device 5 also includes a programmable controller (not shown in the figure), the programmable controller is connected to the electrostatic generator 521, the powder dropping trough 51 includes a plurality of, and different powder materials are contained in the plurality of powder dropping troughs 51, which are used to control the electrostatic generators in different areas to be charged or discharged according to the preset powder spreading shape.

[0059] The powder is placed in the powder drop groove 51, and the powder outlet 53 of the powder drop groove 51 is linear, and the powder outlet 53 of the powder drop groove is close to the adsorption roller. The electrostatic generator 521 is arrayed in N rows and N columns on the circumferential surface of the roller body, and static electricity can be generated according to the electrostatic generator 521 of the selected row and column. The single generator of the electrostatic generator 521 array can be programmably controlled whether it carries static electricity; the surface of the adsorption roller 52 carries positive static electricity, and the shape of the generated static electricity area can be freely programmed and controlled; when the adsorption roller 52 rotates through the powder outlet 53 of the powder drop groove 51, the static electricity area automatically adsorbs the powder according to the shape of the area to be spread; when the adsorption roller 52 adsorbs the powder and rotates to the processing table position, the static electricity is eliminated after being conducted by the metal powder, and the powder is naturally spread on the processing table according to the programmed shape.

[0060] The powder spreading mechanism 5 spreads powder along the horizontal direction of the substrate under the driving action of the driving mechanism 6, and the binder spraying and curing mechanism 3 sprays the binder along the vertical direction of the substrate and solidifies the sprayed powder layer.

[0061] The present invention can also use different metal powders for paving according to different material requirements of different parts. As a specific embodiment, Figure 7 As shown, the component 10 is made of different metal powders, which may include copper, aluminum and iron. The outermost part is copper because copper has good thermal and electrical conductivity, while the middle part is aluminum, which is lighter and can reduce the mass of the molded component. The innermost part is iron, which has a higher strength and can ensure the strength of the molded component as a whole. The selective area powder spreading method described in the present invention can improve the customizability of the parts.

[0062] The present invention is not limited to the additive manufacturing of metal powders, but can also be non-metallic powder materials, or a combination of metal powders and non-metallic powders. Existing metal additive manufacturing methods cannot print mixed metal powders and non-metallic powders. Even if they can be printed, there is a problem that the metal powders and non-metallic powders cannot be screened and recycled. When the powder spreading mechanism 5 spreads the powder, the powder can be laid according to the cross-sectional shape of the graphic slicing software.

[0063] Compared with the additive manufacturing method in the prior art, when spreading powder, it is necessary to spread powder on the entire substrate surface used for printing and forming, and the powder spreading area is larger. Especially for large-format laser forming manufacturing, this powder spreading method will cause a large waste of powder and high cost.

[0064] The sintering module 4 adopts laser sintering or electron beam sintering. The existing SLM additive manufacturing process usually uses laser as a heat source to print layer by layer. This printing method has the problems of high cost and low efficiency, and the molding quality is sensitive to the changes in laser scanning parameters. A slight change in the laser parameters may cause the product printing quality to not meet the requirements, and the molding quality is difficult to guarantee. The present invention can select different sintering methods according to the requirements of powder and performance. When laser sintering is adopted for part of the metal powder area, the sintering module can be the existing laser sintering method, and the remaining part of the metal powder area is solidified by a binder, and then sintered in combination with a sintering furnace, and the pre-printed molded part is transferred to the sintering furnace for high-temperature sintering.

[0065] The present invention can also use a combination of laser sintering and sintering furnace sintering, which can be determined specifically according to the type of powder. For example, according to the structural characteristics of different parts that need to be formed, the internal area is sintered by laser, and the external area is sintered by adhesive curing combined with sintering furnace. As a specific embodiment, copper powder is cured by adhesive and sintered in a sintering furnace, and high-temperature nickel-based alloys are sintered by laser. The reason for using two sintering methods is to make full use of the advantages of the two methods: the adhesive method does not need to consider the powder screening problem too much, and the special powder is directly cured and then sintered in the sintering furnace. However, the method of combining the adhesive with the sintering furnace has the problem of poor density and low mechanical properties of the workpiece. The density of laser sintering is relatively better and the mechanical properties are higher, but the laser processing area needs to consider how to clean the powder. Here is the area that needs good density and high mechanical strength, and laser sintering may be considered. However, only the function is emphasized: for example, areas such as thermal conductivity, heat dissipation, high airtightness, and rapid cooling can be sintered by adhesive combined with sintering wheel.

[0066] like Figure 8 As shown, another embodiment of the present invention further provides an additive manufacturing method based on multi-powder selective regional powder spreading, comprising the steps of:

[0067] S1. Build a three-dimensional model of the part and slice it;

[0068] S2. According to the cross-sectional diagram after slicing and the corresponding powder requirements of different regional positions, laying the same or different powder materials at different positions on the upper surface of the substrate or the support to form a powder layer;

[0069] S3, spraying a layer of binder on at least part of the powder area laid in step S2 and curing it,

[0070] and / or directly sintering or melting at least a portion of the powder region using an energy beam;

[0071] After all the powder areas are solidified, the substrate is lowered to a preset height;

[0072] S4, repeating steps S2 to S3 to form a pre-printed workpiece;

[0073] S5, placing the pre-printed workpiece into a sintering furnace for sintering, so that the binder is volatilized to form a molded part;

[0074] S6. Air-cool the molded parts.

[0075] The step S2 is to lay the same or different powder materials at different positions on the upper surface of the substrate or the support to form a powder layer, including powdering and powdering. Specifically, powdering is that when the adsorption roller 52 rotates through the powder outlet 53 of the powder dropping groove 51, the electrostatically charged area automatically adsorbs the powder according to the shape of the area to be spread; specifically, when the adsorption roller 52 adsorbs the powder and rotates to the position of the processing table, the static electricity is eliminated after being conducted by the metal powder, and the powder is naturally laid on the processing table according to the programmed shape.

[0076] When the powder suction roller 52 reaches the required powder spreading area, powder is dropped by electric neutralization, local static electricity is released through the ground wire, and the powder loading device continues to move forward along the guide rail. One side of the powder suction roller 52 rotates to release powder while the other side sucks powder.

[0077] In the step S2, the binder should have good fluidity and can be sprayed by using an existing nozzle spraying method. The spray nozzle can use an existing atomizing nozzle and a micro-spraying nozzle. The atomizing nozzle is suitable for large-area laser forming; the micro-spraying nozzle is suitable for high-precision, small-area forming. In the step S2, exposure is performed after curing, and ultraviolet light can be used for photocuring. If photocuring is not used, deformation will occur due to the influence of weight as the number of layers increases. The curing is specifically performed by using ultraviolet light or infrared light.

[0078] The thickness of the powder layer is specifically 0.01 mm to 0.2 mm.

[0079] The sintering temperature ranges from 500° C. to 1500° C. The specific sintering temperature can be determined according to the specific type of powder. For example, the sintering temperature of titanium alloy metal powder is generally above 1000° C. The sintering method includes laser sintering and / or sintering furnace sintering.

[0080] The present invention provides an alternative printing method, that is, after laying a layer of metal powder, a layer of binder is sprayed for bonding and curing, and a preformed component is obtained by such a cycle, and finally the preformed component is sintered as a whole to obtain a formed component. Compared with the existing method that needs to rely on laser for layer-by-layer sintering, the present invention can not only improve the printing efficiency and reduce the cost, but also simplify the process flow and ensure the quality of the product. Compared with the existing technology that uses a single metal powder melting method, the present invention can select suitable metal powder for molding according to the performance requirements of different parts of the component by selective regional powder laying, thereby improving the customizability of the component. In addition, compared with the existing selective laser powder melting, powder can only be laid on the part that needs to be formed, avoiding the laying of powder on the entire substrate or support surface, which can effectively reduce the waste and loss of powder. The existing metal additive manufacturing method cannot mix metal powder and non-metallic powder for printing. Even if it can be printed, there is a problem that the metal powder and non-metallic powder cannot be screened and recycled. The additive manufacturing device provided by the present invention is not limited to the additive manufacturing of metal powder, but can also be a non-metallic powder material, or a combination of metal powder and non-metallic powder, and there will be no problem of cleaning powder.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An additive manufacturing method based on multi-powder selective regional powder spreading, characterized in that: Includes steps: (1) Create a three-dimensional model of the part and slice it; (2) laying the same or different powder materials at different positions on the upper surface of the substrate or the support to form a powder layer according to the cross-sectional diagram after slicing and the corresponding powder requirements at different regional positions; (3) spraying a layer of binder on at least part of the powder area laid in step (2) and curing it, and / or directly sintering or melting at least a portion of the powder region using an energy beam; After all the powder areas are solidified, the substrate is lowered to a preset height; (4) Repeat steps (2) to (3) to form a pre-printed workpiece; (5) placing the pre-printed workpiece into a sintering furnace for sintering, so that the binder is volatilized to form a molded part; (6) Air cool the molded parts.

2. The additive manufacturing method based on multi-powder selective regional powder spreading according to claim 1 is characterized in that: The step (3) includes spraying a layer of binder on a part of the powder area in step (2) and curing it, and sintering and curing the remaining powder area by laser sintering, and the energy beam is a laser or an electron beam.

3. The additive manufacturing method based on multi-powder selective regional powder spreading according to claim 1 is characterized in that: The thickness of the powder layer is 0.01 mm to 0.2 mm.

4. The additive manufacturing method based on multi-powder selective regional powder spreading according to claim 1 is characterized in that: In the step (2), laying the same or different powder materials at different positions on the upper surface of the substrate or the support to form a powder layer specifically includes powdering and powder dropping. The powdering specifically refers to that when the adsorption roller rotates through the powder outlet of the powder dropping trough, the electrostatically charged area on the surface of the adsorption roller automatically adsorbs the powder according to the shape of the area to be spread; the powder dropping specifically refers to that when the adsorption roller adsorbs the powder and rotates to the processing table position, the static electricity on the adsorption roller is eliminated, and the powder is naturally spread on the processing table according to the programmed shape.

5. The additive manufacturing method based on multi-powder selective regional powder spreading according to claim 1, characterized in that: The sintering temperature in step (5) is in the range of 500°C to 1500°C.

6. The additive manufacturing method based on multi-powder selective regional powder spreading according to claim 1, characterized in that: The curing is specifically performed by using ultraviolet / infrared light.

7. An additive manufacturing device based on multi-powder selective regional powder spreading, used to implement the additive manufacturing method as claimed in any one of claims 1 to 6, characterized in that: include: A workbench base and a powder spreading mechanism, a binder spraying and curing mechanism, a sintering module, and a driving mechanism installed on the workbench base; The substrate is fixed on the workbench base; The powder spreading mechanism is used to spread different powder materials on different positions of the substrate or the support member according to needs; The binder spraying and curing mechanism is used to spray a layer of binder onto the powder layer and perform curing; The sintering module is located above the substrate and is used to sinter or melt the powder; The driving mechanism is used to control the movement of the powder spreading mechanism and / or the binder spraying and curing mechanism.

8. The additive manufacturing method based on multi-powder selective regional powder spreading according to claim 7, characterized in that: The powder spreading mechanism spreads powder along the horizontal direction of the substrate, and the binder spraying and curing mechanism sprays the binder along the vertical direction of the substrate and cures the sprayed powder layer.

9. The additive manufacturing method based on multi-powder selective regional powder spreading according to claim 7, characterized in that: The different powder materials include metal powder and non-metal powder.

10. The additive manufacturing method based on multi-powder selective regional powder spreading according to claim 9, wherein the powder spreading mechanism comprises a powder dropping groove and an adsorption roller, wherein the powder dropping groove comprises a plurality of powder dropping grooves, wherein different powder materials are contained in the plurality of powder dropping grooves, and the adsorption roller comprises a roller body, and a plurality of electrostatic generators uniformly arrayed in the circumferential direction and axial direction of the outer surface of the roller body; When the adsorption roller rotates and passes the powder outlet of the powder drop trough, the electrostatically charged area automatically adsorbs the powder according to the shape of the area to be spread. When the adsorption roller adsorbs the powder and rotates to the processing table, the static electricity on the adsorption roller is eliminated, and the powder is naturally spread on the processing table according to the programmed shape; The powder spreading device further comprises a programmable controller, which is connected to the electrostatic generator and is used for controlling the electrostatic generators in different areas to charge or discharge according to a preset powder spreading shape.

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