Metal micro-nano particle injection molding method

Abstract

The invention discloses a metal micro-nano particle spray forming method, belongs to the technical field of 3D printing, and solves the problem that the existing metal printing technology needs to be improved to keep the advantage of high efficiency and increase the advantage of high production precision. Comprising the following steps: preparing materials, namely preparing micro-nano scale metal particle turbid liquid and a support material which does not react with the micro-nano scale metal particle turbid liquid; modeling, inputting and determining a part model, and importing the part model into a printing system; and printing, specifically, a supporting material is sprayed out through a supporting spray head in a printing system to construct a supporting mold, and micro-nano-scale metal particle turbid liquid is sprayed out of the supporting mold through a metal spray head in the printing system for filling through photocuring forming. The micro-nano metal particle turbid liquid and the supporting material are used, blocking of a spray head is avoided through turbid liquid spraying, it is ensured that the precision of parts is high, continuous spraying can be achieved, a solvent is rapidly volatilized, the strength of a primary blank is enhanced, the supporting material is rapidly removed, and high-precision and rapid 3D metal printing is achieved.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular to a method for jet forming of metal micro / nano particles. Background Technology

[0002] 3D printing, also known as additive manufacturing, is a manufacturing technology that builds three-dimensional objects by adding material layer by layer. This technology allows for the direct fabrication of complex geometries from digital models without the need for traditional molds or tools. Materials used in 3D printing include plastics, resins, metals, ceramics, and more, which can be in powder, filament, or liquid form. The printing process typically involves a moving print head or laser that precisely places or solidifies material according to instructions in a computer-aided design (CAD) file. 3D printing is widely used in prototyping, industrial design, architectural modeling, medical, and dental fields, and is favored for its ability to rapidly create personalized and complex structures. With technological advancements, 3D printing continues to develop and improve in terms of materials science, printing speed, and cost-effectiveness.

[0003] Metal 3D printing, also known as metal powder sintering or additive manufacturing, is a type of 3D printing that builds complex three-dimensional solid models by adding metal powder layer by layer. The core of this technology lies in using a high-energy source, such as a laser or electron beam, to scan a powder bed along a pre-defined path, melting and solidifying the metal powder in selected areas. This process is repeated until the entire part is completed. The advantages of metal 3D printing include high design freedom, easily achieving complex geometries, reducing reliance on molds, improving material utilization, and shortening production cycles. Furthermore, metal 3D printing shows broad application potential in industries such as aerospace, medical, automotive manufacturing, and energy, especially in manufacturing lightweight, structurally complex parts. With continuous technological advancements, metal 3D printing is constantly developing and improving in terms of materials science, printing speed, and cost-effectiveness, bringing new opportunities and challenges to the manufacturing industry.

[0004] However, current metal 3D printing technology can only perform relatively complex three-dimensional solid modeling and printing operations, but its accuracy is far from meeting people's requirements. Therefore, for parts with low accuracy requirements, metal 3D printing can be the first choice, while for parts with high accuracy requirements, metal injection molding using powder metallurgy technology is mainly used. This involves mixing metal powder with a binder, then using an injection molding machine to inject the mixture into a mold to form a blank of the desired shape. Afterwards, the binder is removed through debinding and sintering processes, and the metal powder is densified, ultimately resulting in high-precision, high-strength metal parts.

[0005] However, the most obvious drawback of metal injection molding using powder metallurgy is that the process is long and requires corresponding precision molds for molding. In addition, the technology requires the use of a large amount of powder binder, which causes environmental pollution.

[0006] Therefore, current metal printing technology needs to be improved to retain its high efficiency while also increasing its high production precision.

[0007] Therefore, a metal micro / nano particle spraying method is proposed to solve or alleviate the above problems. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for spray forming of metal micro / nano particles.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A method for spray forming of metal micro / nano particles includes the following steps. Materials were prepared to produce a suspension of micro / nano-scale metal particles and a support material that does not react with the former. Modeling, inputting and defining the part model, and importing it into the printing system; Printing involves using a support nozzle in a printing system to eject support material to construct a support mold, and then using photopolymerization to form a metal preform. In this process, a metal nozzle in the printing system ejects a suspension of micro-nano-scale metal particles into the support mold to fill it, and then photopolymerization accelerates solidification to obtain a metal preform encapsulated in support material. To remove impurities, the metal preform wrapped with support material is placed in a corresponding organic solvent and vibrated to remove the support material wrapped on the outside, thus obtaining the metal preform. Sintering involves placing the metal blank into a vacuum sintering furnace and sintering it at high temperature to obtain a metal sample.

[0010] Preferably, the micro / nano-scale metal particle suspension includes a solvent, micro / nano-scale metal particles, and an organic dispersant.

[0011] Preferably, the modeling process, which involves inputting and defining the part model and importing it into the printing system, includes the following steps: Input and determine the part model and its dimensions in the control module; Based on the printing layer height and the height of the part model, the part model is divided into several sectional views from bottom to top; The hollow area is detected by a test algorithm of points within polygons in each cross-sectional view, and the outer contour area and the hollow area are extracted by Boolean operation. The hollow area is marked as the first-level support spraying area in each cross-sectional view, and the area between the outer contour area and the hollow area is marked as the suspension spraying area in each cross-sectional view. Calculate the convex hull from each cross-sectional view, and geometrically expand the convex hull to form an outer convex hull. Mark the area between the outer convex hull and the outer contour region as the secondary support spraying area in each cross-sectional view. The output results show that the primary support spraying region and the secondary support spraying region spray support material, and the suspension spraying region sprays micro-nano-scale metal particle suspension.

[0012] Preferably, the modeling process, which involves inputting and defining the part model and importing it into the printing system, further includes the following steps: Comparing the previous and next sectional views, if the projection of the outer convex hull of the previous sectional view covers the outer convex hull of the next sectional view, the output result is the unsupported spraying limit starting point. Comparing the previous and next sectional views, if the projection of the outer convex hull of the previous sectional view partially covers the outer convex hull of the next sectional view, the output result is that there is a support for the injection limiting starting point. When the output result indicates the existence of a support injection limit start point, the overlap between the projection of the outer convex hull of the previous layer section view and the outer convex hull of the next layer section view is determined as the support injection limit start point, and the injection priority at the overlap between the projection of the outer convex hull of the previous layer section view and the outer convex hull of the next layer section view is always greater than the injection priority at the non-overlapping point.

[0013] Preferably, the printing system includes an illumination module, a metal jetting module, a support jetting module, a spotlight module, and a control module. The control module is electrically connected to the illumination module, the metal jetting module, the support jetting module, and the spotlight module, and controls the start and stop operation of the illumination module, the metal jetting module, the support jetting module, and the spotlight module. The metal jetting module is used to adjust the orientation of the metal nozzle and to jet a suspension of micro-nano-scale metal particles. The support jetting module is used to adjust the mode of the support nozzle and to jet support material. The illumination module is used to provide UV light to the printed support material and the printed micro-nano-scale metal particle suspension. The spotlight module is used to provide a focused light source to the jetted micro-nano-scale metal particle suspension after a delay following jetting by the metal jetting module.

[0014] Preferably, the illumination module includes an illumination displacement component and an ultraviolet light source. The ultraviolet light source is fixedly connected to the movable end of the illumination displacement component. Both the illumination displacement component and the ultraviolet light source are coupled to the control module. The illumination displacement component controls the ultraviolet light source to move within space.

[0015] Preferably, the point light module includes a point light displacement component and a UV laser. The UV laser is fixedly connected to the movable end of the point light displacement component. Both the point light displacement component and the UV laser are coupled to a control module. The UV laser is used to focus the light source and emit ultraviolet laser light, which then acts on the sprayed micro-nano-scale metal particle suspension. The point light displacement component is used to controllably drive the UV laser to move and delay the light spot displacement onto the sprayed micro-nano-scale metal particle suspension.

[0016] Preferably, the support spraying module includes a support nozzle, a support material feeding unit, and a support material spraying control unit. The support nozzle is connected to the support material feeding unit, and the support material spraying control unit is coupled to the support material feeding unit. The support material spraying control unit is used to control the amount and speed of support material supplied by the support material feeding unit. The support material spraying control unit is coupled to a control module, and the control module is used to transmit control information to the support material spraying control unit.

[0017] Preferably, the metal spraying module includes a metal nozzle, a suspension feeding unit, and a suspension spraying control unit. The metal nozzle is connected to the suspension feeding unit, and the suspension spraying control unit is coupled to the suspension feeding unit. The suspension spraying control unit is used to control the amount and speed of suspension spraying provided by the suspension feeding unit. The suspension spraying control unit is coupled to a control module, and the control module is used to transmit control information to the suspension spraying control unit.

[0018] Preferably, it further includes a jet displacement component, which is coupled to the control module. The metal nozzle and the support nozzle are both disposed on the movable end of the jet displacement component, and the jet displacement component is used to controllably drive the metal nozzle and the support nozzle to move within space.

[0019] The present invention has the following beneficial effects: In order to produce high-precision metal parts, this invention uses a suspension of micro-nano-scale metal particles that meets the requirements and an incompatible and non-reactive support material. These materials are delivered to their respective nozzles through an independent pipeline system. Since both materials are in liquid state, each nozzle can precisely control the spray volume at the picoliter level, thus ensuring the high precision of the parts. Because of the use of micro-nano-scale metal particle suspensions, the nozzle is less prone to clogging and can operate continuously for extended periods. After spraying, the organic solvent in the micro-nano-scale metal particle suspension evaporates under light irradiation, giving the metal preform a certain strength and preventing it from disintegrating. At the same time, thanks to the characteristics of the micro-nano-scale metal particle suspension and the non-reactive support material, after the metal preform is wrapped by the support material, it can be quickly detached by simply placing it in an organic solvent and vibrating it slightly, leaving the metal preform for sintering. This method not only maintains the high precision of metal injection molding in powder metallurgy but also integrates the rapid prototyping advantages of 3D metal printing, achieving a dual improvement in efficiency and precision. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0024] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0025] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0026] Furthermore, the terms "first," "second," and "third" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0027] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] A method for spray forming of metal micro / nano particles, such as Figure 1 As shown, it includes the following steps: Materials were prepared to produce a suspension of micro / nano-scale metal particles and a support material that does not react with the former. Modeling, inputting and defining the part model, and importing it into the printing system; Printing involves using a support nozzle in a printing system to eject support material to construct a support mold, and then using photopolymerization to form a metal preform. In this process, a metal nozzle in the printing system ejects a suspension of micro-nano-scale metal particles into the support mold to fill it, and then photopolymerization accelerates solidification to obtain a metal preform encapsulated in support material. To remove impurities, the metal preform wrapped with support material is placed in a corresponding organic solvent and vibrated to remove the support material wrapped on the outside, thus obtaining the metal preform. Sintering involves placing the metal blank into a vacuum sintering furnace and sintering it at high temperature to obtain a metal sample.

[0029] In practical operation, this invention involves configuring a suspension of micro / nano-scale metal particles that meets the requirements, along with a non-reactive support material. These particles are delivered to different nozzles via various pipelines. Each nozzle sprays a volume within the picoliter range, ensuring precise spraying and thus guaranteeing high accuracy of the final part sample. Furthermore, the use of a micro / nano-scale metal particle suspension reduces nozzle clogging, allowing for continuous spraying over extended periods. After spraying, the organic solvent in the suspension evaporates using a light source, giving the metal preform sufficient strength and preventing it from crumbling. The presence of the micro / nano-scale metal particle suspension and the non-reactive support material also allows for rapid removal of the support material when the metal preform, encased in the support material, is placed in a suitable organic solvent and vibrated. Only the metal preform remains for subsequent sintering. This method ensures that the metal parts printed using this method not only possess the high precision of powder metallurgy injection molding but also the rapid prototyping efficiency of 3D metal printing.

[0030] Preferably, the micro / nano-scale metal particle suspension includes a solvent, micro / nano-scale metal particles, and an organic dispersant.

[0031] The micro-nano-scale metal particle suspension is configured according to the above content to ensure that the micro-nano-scale metal particles are uniformly distributed in the suspension and are not prone to aggregation or oxidation. This allows the micro-nano-scale metal particles to be transported in fluid form, reducing the difficulty of transporting them and preventing dry friction between the micro-nano-scale metal particles and the metal nozzle. This avoids wear at the nozzle that could lead to an increase in its diameter or deformation.

[0032] Preferably, modeling, inputting and defining the part model, and importing it into the printing system includes the following steps: Input and determine the part model and its dimensions, including its height, in the control module; Based on the printed layer height y and the part model height x, the part model is divided into several sectional views from bottom to top. The number of sectional views is... ,in, Furthermore, the cross-sectional view of each layer can be obtained through height values. To locate; For each section view i, by setting the plane Where the normal vector of the plane is That is, the plane is parallel to the Z-axis and passes through the height Place; For each face of the mesh, calculate the plane. The lines of intersection between the face and the plane, each mesh face may have zero or one or more intersection points with the plane, assuming face f is formed by vertices , , Composition, surfaces and planes The intersection points between them can be calculated from the intersection points of the line segments and the plane, for each edge. The intersection point is calculated using Formula 1. Formula 1: , where t satisfies the plane equation Connect all intersection points to form the cross-sectional view of this layer, and output each cross-sectional view; The hollow areas are detected by testing the points within the polygons in each cross-sectional view, such as the ray method. The outer contour area and the hollow areas are extracted by Boolean operations, such as the difference operation. The hollow areas are marked as the first-level support spraying areas in each cross-sectional view, and the area between the outer contour area and the hollow areas is marked as the suspension spraying area in each cross-sectional view. Set a minimum distance of W pixels between the external convex hull and the cross-sectional view. Calculate the convex hull from each cross-sectional view and geometrically dilate it to form the external convex hull. Specifically, move the convex hull by W pixels along the normal direction based on all intersection points in the cross-sectional view. And mark the area between the outer convex hull and the outer contour region as the secondary support spraying area in each sectional view; The output results show that the primary support spraying region and the secondary support spraying region spray support material, and the suspension spraying region sprays micro-nano-scale metal particle suspension.

[0033] Through the above steps and methods, the printing system can determine the minimum volume required for printing the part model during the printing process, thereby saving material consumption for the entire part model printing. It can also determine the areas for spraying the support material and the areas for spraying the micro / nano-scale metal particle suspension. This ensures that the part model is pre-divided into different layers according to the printing layer height, and that each layer of the part model is first printed with support material and then cured, providing space for the spraying of the micro / nano-scale metal particle suspension. It also determines the amount of micro / nano-scale metal particle suspension used, avoiding overuse. Furthermore, by pre-determining the spraying area of ​​the support material, the subsequent spraying of the micro / nano-scale metal particle suspension is confined within the space provided by the support material. Since the evaporation rate of the organic solvent in the micro / nano-scale metal particle suspension is significantly slower than the curing rate of the support material, it avoids the distortion of the part's shape caused by the micro / nano-scale metal particle suspension's lack of direct shaping ability when directly sprayed. Therefore, this method ensures high precision in the parts formed.

[0034] Preferably, modeling, inputting and defining the part model, and importing it into the printing system also includes the following steps: Comparing the previous and next sectional views, if the projection of the outer convex hull of the previous sectional view covers the outer convex hull of the next sectional view, the output result is the unsupported spraying limit starting point. Comparing the previous and next sectional views, if the projection of the outer convex hull of the previous sectional view partially covers the outer convex hull of the next sectional view, the output result is that there is a support for the injection limiting starting point. When the output result indicates the existence of a support injection limit start point, the overlap between the projection of the outer convex hull of the previous layer section view and the outer convex hull of the next layer section view is determined as the support injection limit start point, and the injection priority at the overlap between the projection of the outer convex hull of the previous layer section view and the outer convex hull of the next layer section view is always greater than the injection priority at the non-overlapping point.

[0035] Based on the above method and steps, when the printing system sprays and forms each layer of parts and support materials, it can ensure that the first spray position is attached to the cross-sectional view of the previous layer, avoiding the situation of spraying in mid-air. It also ensures that each time the support material is sprayed, the support material can be based on the cross-sectional view of the previous layer, avoiding the situation where the support material is deformed before it is cured due to the lack of an object to which it is attached, thus affecting the dimensional accuracy.

[0036] Preferably, the printing system includes a light-emitting module, a metal jetting module, a support jetting module, a spotlight module, and a control module. The control module is electrically connected to the light-emitting module, the metal jetting module, the support jetting module, and the spotlight module, and controls the start and stop operation of the light-emitting module, the metal jetting module, the support jetting module, and the spotlight module. The metal jetting module is used to adjust the orientation of the metal nozzle and to jet a suspension of micro-nano-scale metal particles. The support jetting module is used to adjust the mode of the support nozzle and to jet support material. The light-emitting module is used to provide UV light to the printed support material and the printed micro-nano-scale metal particle suspension. The spotlight module is used to provide a focused light source to the jetted micro-nano-scale metal particle suspension after a delay following jetting by the metal jetting module. It should be noted that the control module includes a controller and a processor. The processor is coupled to the controller, and the controller is coupled to the light-emitting module, the metal jetting module, the support jetting module, and the spotlight module. The processor can be coupled to an input module, such as a mouse, keyboard, or touch screen.

[0037] When the printing system prints according to this method, it ensures that the control module controls the illumination module, metal jetting module, support jetting module, and spotlight module. This ensures that during the jetting process of the metal jetting and support jetting modules, the illumination module continuously provides UV light, allowing the support material to solidify rapidly while also providing heat to the jetted micro / nano-scale metal particle suspension. This accelerates the evaporation of organic solvents in the micro / nano-scale metal particle suspension and speeds up its solidification. Furthermore, the control module also needs to control the spotlight module when the metal jetting module begins jetting the micro / nano-scale metal particle suspension. Subsequently, after the micro-nano-scale metal particle suspension has been sprayed for a certain time, length, or amount in each cross-sectional view, the point light module starts working again, providing a focused light source to act on the sprayed micro-nano-scale metal particle suspension, and positioning it according to the spraying path of the metal spraying module. This ensures that the sprayed micro-nano-scale metal particle suspension receives the focused light source for the same amount of time, thereby accelerating the evaporation of organic solvents and solidification of the micro-nano-scale metal particle suspension. This ensures that when spraying the next cross-sectional view, both the support material and the micro-nano-scale metal particle suspension can adhere to the solid, rather than to the unsolidified material.

[0038] Preferably, the illumination module includes an illumination displacement component and an ultraviolet light source. The ultraviolet light source is fixedly connected to the movable end of the illumination displacement component. Both the illumination displacement component and the ultraviolet light source are coupled to the control module. The illumination displacement component controls the ultraviolet light source to move within space.

[0039] Specifically, the light displacement component is a first robotic arm or other structure that can move the ultraviolet light source in space to achieve the same effect. The controlled end of the first robotic arm is coupled to the control module. The ultraviolet light source is a UV lamp. The UV lamp is installed on the movable end of the first robotic arm and is connected to the power supply through a first relay. The controlled end of the first relay is coupled to the control module.

[0040] When the illumination module is working, the control module can send a signal to the first relay to control the UV lamp to be powered on. At the same time, it can also control the first robotic arm to drive the UV lamp to face the part being sprayed and maintain a constant distance, ensuring that the support material can be quickly solidified under the irradiation of the UV lamp. It also provides a heat source for the micro-nano scale metal particle suspension, allowing the organic solvent in it to evaporate as soon as possible.

[0041] Preferably, the spotlight module includes a spotlight displacement component and a UV laser. The UV laser is fixedly connected to the movable end of the spotlight displacement component. Both the spotlight displacement component and the UV laser are coupled to the control module. The UV laser is used to focus the light source and emit ultraviolet laser light, which acts on the sprayed micro-nano scale metal particle suspension. The spotlight displacement component is used to controllably drive the UV laser to move and delay the movement of the light spot to the sprayed micro-nano scale metal particle suspension.

[0042] The spotlight displacement device can actually be a second robotic arm or other structure that can drive the ultraviolet light source to move in space and achieve the same effect. The controlled end of the second robotic arm is coupled to the control module. The UV laser is installed on the movable end of the second robotic arm and is also coupled to the control module. When the spotlight module needs to delay the displacement of the light spot to the sprayed micro-nano-scale metal particle suspension, it can asynchronously delay the displacement based on the command output by the control module to the spray displacement device. This allows the second robotic arm to carry the ultraviolet light spot emitted by the UV laser to irradiate the sprayed micro-nano-scale metal particle suspension and move along the same trajectory as the metal spray module. This ensures that the sprayed micro-nano-scale metal particle suspension can be uniformly irradiated by the ultraviolet light spot, thereby ensuring that the organic solvent in the micro-nano-scale metal particle suspension at each point in each cross-sectional view can evaporate and solidify.

[0043] Preferably, the support spraying module includes a support nozzle, a support material feeding unit, and a support material spraying control unit. The support nozzle is connected to the support material feeding unit, and the support material spraying control unit is coupled to the support material feeding unit. The support material spraying control unit is used to control the amount and speed of support material supplied by the support material feeding unit. The support material spraying control unit is coupled to a control module, and the control module is used to transmit control information to the support material spraying control unit.

[0044] The support material supply unit includes a first supply tank, a first supply pipe connected to the first supply tank and the support nozzle, a first booster pump connected to the first supply pipe, and a first solenoid valve connected to the first supply pipe. The support material spraying control unit includes a first motor drive chip and a second relay. The servo motor in the first booster pump is coupled to the controller through the first motor drive chip, and the first solenoid valve is coupled to the controller through the second relay. When the support spraying module needs to work, it can control the second relay to conduct and energize and open the first solenoid valve, thereby keeping the first supply pipe unobstructed. Then, the first motor drive chip controls the servo motor in the first booster pump to drive the first booster pump to work, thereby guiding the support material in the first supply tank out for spraying through the support nozzle. It should be noted that the support material needs to be fluid, photocurable, and soluble in organic solvents, such as photocurable polyurethane, and is not limited to the materials provided above.

[0045] Preferably, the metal spraying module includes a metal nozzle, a suspension feeding unit, and a suspension spraying control unit. The metal nozzle is connected to the suspension feeding unit, and the suspension spraying control unit is coupled to the suspension feeding unit. The suspension spraying control unit is used to control the amount and speed of the suspension supplied by the suspension feeding unit. The suspension spraying control unit is coupled to a control module, and the control module is used to transmit control information to the suspension spraying control unit.

[0046] The suspension feeding unit includes a second feeding tank, a second feeding pipe connected to the second feeding tank and the metal nozzle, a second booster pump connected to the second feeding pipe, and a second solenoid valve connected to the second feeding pipe. The suspension spray control unit includes a second motor drive chip and a third relay. The servo motor in the second booster pump is coupled to the controller through the second motor drive chip, and the second solenoid valve is coupled to the controller through the third relay. When the metal spraying module needs to operate, it can control the third relay to conduct and energize and open the second solenoid valve, thereby keeping the second feeding pipe unobstructed. Then, the second motor drive chip controls the servo motor in the second booster pump to drive the second booster pump to work, thereby guiding the micro-nano-scale metal particle suspension in the second feeding tank out and spraying it through the metal nozzle. Through this spraying method, the spraying volume of the micro-nano-scale metal particle suspension can be precisely controlled, avoiding cost waste.

[0047] Preferably, it also includes a jet displacement component, which is coupled to the control module. The metal nozzle and the support nozzle are both disposed on the movable end of the jet displacement component, which is used to controllably drive the metal nozzle and the support nozzle to move within space.

[0048] The spray displacement component can actually be a third robotic arm, or other structures that can drive the metal nozzle and support nozzle to move in space and play the same role, or it can be a structure such as a three-axis motion module.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for spray forming of metal micro / nano particles, characterized in that, Includes the following steps, Materials were prepared to produce a suspension of micro / nano-scale metal particles and a support material that does not react with the former. Modeling, inputting and defining the part model, and importing it into the printing system; Printing involves using a support nozzle in a printing system to eject support material to construct a support mold, and then using photopolymerization to form a metal preform. In this process, a metal nozzle in the printing system ejects a suspension of micro-nano-scale metal particles into the support mold to fill it, and then photopolymerization accelerates solidification to obtain a metal preform encapsulated in support material. To remove impurities, the metal preform wrapped with support material is placed in a corresponding organic solvent and vibrated to remove the support material wrapped on the outside, thus obtaining the metal preform. Sintering involves placing the metal blank into a vacuum sintering furnace and sintering it at high temperature to obtain a metal sample.

2. The method for spray forming of metal micro / nano particles according to claim 1, characterized in that, The micro / nano-scale metal particle suspension includes a solvent, micro / nano-scale metal particles, and an organic dispersant.

3. The method for spray forming of metal micro / nano particles according to claim 1, characterized in that, The modeling process, which involves inputting and defining the part model and importing it into the printing system, includes the following steps: Input and determine the part model and its dimensions in the control module; Based on the printing layer height and the height of the part model, the part model is divided into several sectional views from bottom to top; The hollow area is detected by a test algorithm of points within polygons in each cross-sectional view, and the outer contour area and the hollow area are extracted by Boolean operation. The hollow area is marked as the first-level support spraying area in each cross-sectional view, and the area between the outer contour area and the hollow area is marked as the suspension spraying area in each cross-sectional view. Calculate the convex hull from each cross-sectional view, and geometrically expand the convex hull to form an outer convex hull. Mark the area between the outer convex hull and the outer contour region as the secondary support spraying area in each cross-sectional view. The output results show that the primary support spraying region and the secondary support spraying region spray support material, and the suspension spraying region sprays micro-nano-scale metal particle suspension.

4. The method for spray forming of metal micro / nano particles according to claim 3, characterized in that, The modeling process, which involves inputting and defining the part model and importing it into the printing system, also includes the following steps. Comparing the previous and next sectional views, if the projection of the outer convex hull of the previous sectional view covers the outer convex hull of the next sectional view, the output result is the unsupported spraying limit starting point. Comparing the previous and next sectional views, if the projection of the outer convex hull of the previous sectional view partially covers the outer convex hull of the next sectional view, the output result is that there is a support for the injection limiting starting point. When the output result indicates the existence of a support injection limit start point, the overlap between the projection of the outer convex hull of the previous layer section view and the outer convex hull of the next layer section view is determined as the support injection limit start point, and the injection priority at the overlap between the projection of the outer convex hull of the previous layer section view and the outer convex hull of the next layer section view is always greater than the injection priority at the non-overlapping point.

5. The method for spray forming of metal micro / nano particles according to claim 1, characterized in that, The printing system includes an illumination module, a metal jetting module, a support jetting module, a spotlight module, and a control module. The control module is electrically connected to the illumination module, metal jetting module, support jetting module, and spotlight module, and controls the start and stop operation of the illumination module, metal jetting module, support jetting module, and spotlight module. The metal jetting module is used to adjust the orientation of the metal nozzle and to jet a suspension of micro-nano-scale metal particles. The support jetting module is used to adjust the mode of the support nozzle and to jet support material. The illumination module is used to provide UV light to the printed support material and the printed micro-nano-scale metal particle suspension. The spotlight module is used to provide a focused light source to the jetted micro-nano-scale metal particle suspension after a delay following jetting by the metal jetting module.

6. The method for spray forming of metal micro / nano particles according to claim 5, characterized in that, The illumination module includes an illumination displacement component and an ultraviolet light source. The ultraviolet light source is fixedly connected to the movable end of the illumination displacement component. Both the illumination displacement component and the ultraviolet light source are coupled to the control module. The illumination displacement component controls the ultraviolet light source to move within space.

7. The method for spray forming of metal micro / nano particles according to claim 5, characterized in that, The point light module includes a point light displacement component and a UV laser. The UV laser is fixedly connected to the movable end of the point light displacement component. Both the point light displacement component and the UV laser are coupled to a control module. The UV laser is used to focus the light source and emit ultraviolet laser light, which then acts on the sprayed micro-nano-scale metal particle suspension. The point light displacement component is used to controllably drive the UV laser to move and delay the movement of the light spot onto the sprayed micro-nano-scale metal particle suspension.

8. The method for spray forming of metal micro / nano particles according to claim 5, characterized in that, The support spraying module includes a support nozzle, a support material feeding unit, and a support material spraying control unit. The support nozzle is connected to the support material feeding unit, and the support material spraying control unit is coupled to the support material feeding unit. The support material spraying control unit is used to control the amount and speed of support material supplied by the support material feeding unit. The support material spraying control unit is coupled to a control module, which is used to transmit control information to the support material spraying control unit.

9. The method for spray forming of metal micro / nano particles according to claim 8, characterized in that, The metal spraying module includes a metal nozzle, a suspension feeding unit, and a suspension spraying control unit. The metal nozzle is connected to the suspension feeding unit, and the suspension spraying control unit is coupled to the suspension feeding unit. The suspension spraying control unit is used to control the amount and speed of suspension spraying provided by the suspension feeding unit. The suspension spraying control unit is coupled to a control module, and the control module is used to transmit control information to the suspension spraying control unit.

10. The method for spray forming of metal micro / nano particles according to claim 9, characterized in that, It also includes a jet displacement component, which is coupled to the control module. The metal nozzle and the support nozzle are both disposed on the movable end of the jet displacement component. The jet displacement component is used to controllably drive the metal nozzle and the support nozzle to move within space.

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