A binder jetting coaxial feed nozzle and method of powder uniform distribution, method of manufacture and nozzle apparatus

Abstract

The present application relates to a kind of binder jetting coaxial powder feeding nozzle, including shell, nozzle core, connector, nozzle core is located in shell, connector is located above shell;Nozzle core is equipped with binder jetting channel, piezoelectric binder jetting system is loaded in binder jetting channel, the lower end of nozzle core is binder outlet;The inner wall of shell and the outer wall of nozzle core are surrounded between powder chamber and powder channel, powder inlet is provided on shell, the lower end of powder channel is powder outlet, powder inlet, powder chamber, powder channel, powder outlet are sequentially communicated.The present application also relates to a kind of powder uniform distribution method of binder jetting coaxial powder feeding nozzle, a kind of binder jetting coaxial powder feeding nozzle device, a kind of manufacturing method of binder jetting coaxial powder feeding nozzle.The present application innovates the traditional binder jetting forming process, binder and forming powder are jetted out simultaneously by the same nozzle, improves forming efficiency, belongs to binder jetting printing technical field.

Description

Technical Field

[0001] This invention relates to adhesive jet printing technology, specifically to an adhesive jet coaxial powder feeding nozzle, a method for uniform powder distribution using the adhesive jet coaxial powder feeding nozzle, an adhesive jet coaxial powder feeding nozzle device, and a method for manufacturing the adhesive jet coaxial powder feeding nozzle. Background Technology

[0002] 3DP (3D Printing) is an additive manufacturing method based on discrete stacking and microdroplet jetting technology. It has advantages such as low cost, high efficiency, and no special requirements for the processing materials.

[0003] The binder spray nozzle is a crucial component of a binder spray molding system. Its lifespan, spraying effect, and ability to operate stably and continuously significantly impact the green body forming process. In the field of binder spray molding, traditional nozzles have only one function: spraying the binder. A powder-spreading roller lays a layer of molding powder on the substrate, and then the nozzle sprays binder droplets that combine with the powder on the substrate to form a slice layer. This process of spreading powder and spraying binder is repeated to form the green body. Using this type of single-function nozzle results in low forming efficiency, requiring powder spreading before binder spraying. Furthermore, during binder spray molding, the impact force of the nozzle spraying binder causes powder to splatter on the powder bed, affecting the forming effect or splashing near the nozzle. Especially when the molding powder and the coaxial powder feeding nozzle for binder spraying are made of the same material, the mixture of molding powder and binder easily adheres to the nozzle, is difficult to remove, and easily clogs the nozzle, affecting the uniformity and convergence of subsequent powder spraying.

[0004] Adhesive micro-droplet ejection technology can be divided into two main categories: continuous ejection and on-demand ejection. The principle of continuous ejection is that a stable back pressure is applied within the liquid chamber, causing the liquid to be ejected from the nozzle and broken into droplets of uniform size. However, the start and stop of continuous ejection are controlled solely by back pressure, resulting in a slow response. Therefore, to precisely control the droplets, this ejection method must "polarize" the droplets to apply a charge, combined with a "deflection electric field" to control the droplet's direction of movement. Unexploded droplets are collected by an "ink collection tank." Consequently, continuous micro-jet systems are complex in structure, cumbersome in control, and expensive. Summary of the Invention

[0005] To address the technical problems existing in the prior art, the purpose of this invention is to provide a coaxial powder feeding nozzle for binder spraying with high molding efficiency. This innovation revolutionizes the traditional binder spraying molding process, allowing the binder and molding powder to be sprayed simultaneously from the same nozzle, thus improving molding efficiency.

[0006] Another objective of this invention is to provide a method for uniform powder distribution using a coaxial powder feeding nozzle for binder spraying, ensuring uniform powder delivery. This method simplifies the powder feeding system and ensures sufficient bonding between the molded powder and the binder.

[0007] Another object of the present invention is to provide a coaxial powder feeding nozzle device for adhesive spraying with high molding efficiency.

[0008] Another object of the present invention is to provide a method for manufacturing a coaxial powder feeding nozzle for adhesive injection. This method uses a rapid prototyping process for direct manufacturing and, by utilizing the differences in the properties of different materials, improves the economy and performance of the nozzle.

[0009] In this invention, the binder and forming powder are simultaneously ejected from a single nozzle, ensuring uniform powder delivery, the ejection of tiny binder droplets, high forming efficiency, and minimal clogging. Furthermore, this invention utilizes the differences in material properties, employing different materials at different locations within the nozzle to enhance the performance and durability of the coaxial binder spray nozzle, preventing powder and binder from adhering to the nozzle and clogging it.

[0010] This invention utilizes an on-demand spraying technology for adhesive microdroplets, reducing the complexity of the spraying system and lowering costs. It also simplifies the structure and enables system miniaturization. Currently, there are two main types of on-demand spraying methods based on the transduction mechanism: piezoelectric and thermal bubble. For ease of bonding, piezoelectric spraying technology is chosen. Applying a pulsed voltage to the piezoelectric crystal causes it to deform and compress the diaphragm, driving micron-sized adhesive droplets to overcome surface tension and be ejected.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A coaxial adhesive powder feeding nozzle includes a housing, a nozzle core, and a connector. The nozzle core is located inside the housing, and the connector is located above the housing. The nozzle core has an adhesive injection channel, and a piezoelectric adhesive injection system is installed inside the adhesive injection channel. The lower end of the nozzle core is the adhesive outlet. A powder cavity and a powder channel are formed between the inner wall of the housing and the outer wall of the nozzle core. The housing has a powder inlet, and the lower end of the powder channel is the powder outlet. The powder inlet, powder cavity, powder channel, and powder outlet are connected in sequence.

[0013] As a preferred embodiment, the adhesive injection channel is an axially arranged through hole; the piezoelectric adhesive injection system includes a pulse control system, a piezoelectric ceramic, a diaphragm, an adhesive delivery pipe, and an adhesive cavity; the adhesive cavity is located in the lower section of the adhesive injection channel, and a through hole is provided at the upper end of the adhesive cavity, with the diaphragm installed at the through hole; the adhesive delivery pipe extends into the adhesive cavity; the pulse control system is connected to the piezoelectric ceramic, which is located directly above the diaphragm; the liquid adhesive outlet and the powder adhesive outlet are on the same horizontal plane.

[0014] As a preferred embodiment, the connector is a cylinder with internal threads, and a through hole communicating with the adhesive spraying channel is opened at the center of the connector.

[0015] As a preferred embodiment, the outer shell, connector, and nozzle core are integrally formed; the outer shell and nozzle core are coaxially arranged, and the upper side wall of the outer shell has several powder inlets for connecting to an external powder feeding system. Each powder inlet is evenly distributed on the outer shell around the central axis of the nozzle core, and the axial direction of the powder inlet is set along the radial direction of the nozzle core.

[0016] As a preferred embodiment, the number of powder inlets is 1 to 6; the wall thickness of the outer shell corresponding to the powder chamber is 2 to 3 mm; the wall thickness of the nozzle core is 2 to 3 mm; and the wall thickness of the outer shell corresponding to the powder channel is 2 to 3 mm.

[0017] As a preferred embodiment, both the outer shell and the lower section of the nozzle core are inverted cones, forming a powder channel between the two inverted cones; inside the powder chamber, the outer wall of the nozzle core is provided with spiral blades.

[0018] A method for uniform powder distribution using a coaxial powder feeding nozzle for adhesive spraying is provided. The powder feeding system delivers powder through a powder inlet. The powder enters the powder chamber through the powder inlet and collides with the spiral blades. Through rebound or downward spiral, the powder gradually achieves uniform distribution in the powder chamber and is finally discharged through the powder channel along the powder outlet to achieve uniform powder feeding.

[0019] A coaxial powder feeding nozzle device for adhesive spraying, which realizes a method for uniform powder distribution of adhesive spraying coaxial powder feeding nozzle, includes an adhesive spraying coaxial powder feeding nozzle and a powder feeding system, wherein the powder feeding system is connected to the powder inlet.

[0020] A method for manufacturing a coaxial powder feeding nozzle for adhesive injection involves creating a coaxial powder feeding nozzle for adhesive injection by defining a dividing plane at the connection between the powder chamber and the powder channel. The dividing plane is set along the horizontal direction and divides the integrated molding structure of the shell, connector and nozzle core into upper and lower parts. The two parts are manufactured using different materials through rapid prototyping.

[0021] A method for manufacturing a coaxial powder feeding nozzle for adhesive spraying includes the following steps:

[0022] (1) Model drawing: In the 3D CAD software, according to the structural design of the coaxial powder feeding nozzle for adhesive injection, draw the 3D model of the coaxial powder feeding nozzle for adhesive injection. Set a dividing plane at the connection between the powder chamber and the powder channel. Save the upper and lower parts of the 3D model divided by the dividing plane as STL files and export them.

[0023] (2) Slicing process: Using slicing software, the upper and lower parts of the obtained three-dimensional model of the coaxial powder feeding nozzle for adhesive injection are sliced ​​and layered along the forming direction to obtain the slicing data of the model layer interface. Then, the slicing data files are imported into the 3D printing equipment.

[0024] (3) Rapid prototyping: Set the printing parameters on the host computer, use CuSn10 powder to print the part above the powder channel, then switch to Ti6Al4V powder and continue printing the remaining part of the nozzle;

[0025] (4) Post-treatment: Post-treatment of the formed adhesive spraying coaxial powder feeding nozzle;

[0026] (5) Install a piezoelectric adhesive spraying system.

[0027] As a preferred option, in step (1), after drawing the model, the three-dimensional model is first analyzed in the three-dimensional CAD software to check whether there are any errors in the three-dimensional model of the coaxial powder feeding nozzle for adhesive spraying; after confirming that there are no errors, a dividing plane parallel to the XY plane is set at the connection between the powder chamber and the powder channel to divide the three-dimensional model into upper and lower parts, and then the parts are saved as STL format files and exported separately.

[0028] As a preferred option, in step (2), the two STL format files exported in step (1) are imported into the slicing software, the placement of the parts is adjusted, the relative positions of the upper and lower coordinate systems are kept unchanged, and slicing processing is performed to obtain the slicing data file.

[0029] As a preferred method, in step (3), the rapid prototyping method is selective laser melting (SLM). First, CuSn10 powder is used to print the part above the powder channel. After printing is completed, the green blank is kept in the same position on the substrate. Then, the forming powder of the selective laser melting equipment is immediately replaced with Ti6Al4V powder, and the remaining part of the nozzle is printed directly. Finally, the formed complete adhesive spraying coaxial powder feeding nozzle is taken out of the equipment.

[0030] As a preferred option, in step (4), the post-processing specifically involves: peeling the formed adhesive spraying coaxial powder feeding nozzle off the substrate, removing the formed powder from the surface of the adhesive spraying coaxial powder feeding nozzle or the powder cavity, powder channel, and spraying channel inside the nozzle, and polishing and nano-coating the surface and interior of the adhesive spraying coaxial powder feeding nozzle.

[0031] As a preferred option, in step (5), the piezoelectric adhesive spraying system needs to be coaxially aligned with the adhesive spraying channel so that the liquid outlet and powder outlet of the adhesive are located on the same horizontal plane.

[0032] The principle of this invention is:

[0033] During operation, an external pulse control system inputs pulses, causing the piezoelectric ceramic to extend downwards under the action of the pulse voltage signal, compressing the diaphragm below. This creates a pressure change within the adhesive cavity, causing the adhesive to be ejected from the nozzle. Simultaneously, the molding powder enters the powder cavity through the powder inlet via an external powder feeding system. The powder collides with the spiral blades or the nozzle core cylinder, rebounding in various directions onto other spiral blades, the inner surface of the outer shell, or flowing downwards along the spiral, gradually achieving uniform distribution within the powder cavity before finally entering the powder channel for uniform powder discharge. The molding powder and the simultaneously ejected micron-sized adhesive droplets mix thoroughly in the air and are then sprayed onto the substrate as a mixture for molding.

[0034] The present invention has the following advantages:

[0035] 1. This invention sprays molding powder and binder droplets simultaneously from the same nozzle, which improves molding efficiency and avoids powder splashing problems compared to the previous molding process of spreading powder first and then spraying binder.

[0036] 2. The present invention utilizes spiral blades to make the powder bounce continuously or spiral down in the powder chamber, so that the powder entering from the powder inlet is evenly distributed in the powder chamber, thereby achieving uniform powder delivery from the nozzle.

[0037] 3. The inner wall of the powder channel in the nozzle of the present invention is smooth, and the diameter of the channel gradually decreases from the powder chamber to the powder outlet, which can achieve a better powder delivery effect.

[0038] 4. By utilizing the characteristics and advantages of different materials, different materials are selected for processing and manufacturing according to the functional requirements of different parts of the nozzle, avoiding the problem of easy adhesion between homogeneous materials, improving the economy and performance of the coaxial powder feeding nozzle for adhesive spraying, and at the same time achieving the effect of preventing nozzle clogging.

[0039] 5. The nozzle of the present invention can be integrally molded. After rapid molding, it only needs to be assembled with a piezoelectric adhesive spraying system. The operation is simple and the powder feeding effect is good.

[0040] 6. This invention uses additive manufacturing to 3D print the nozzle, which is not limited by traditional processing methods and can quickly form the complex microstructure of the nozzle, ensuring processing accuracy and performance. Attached Figure Description

[0041] Figure 1 This is a three-dimensional structural diagram of the nozzle of the present invention.

[0042] Figure 2 for Figure 1 The device shown is a longitudinal sectional view along the direction of the powder inlet aperture.

[0043] Figure 3 for Figure 1 A partially cutaway three-dimensional schematic diagram of the device shown.

[0044] Figure 4 for Figure 1 A cross-sectional view of the rapid prototyping section of the device shown.

[0045] Figure 5 This is a schematic diagram of the material distribution of the coaxial powder feeding nozzle for adhesive spraying in this invention.

[0046] Figure 6 for Figure 3 A schematic diagram of the working principle of the spiral blades in the device shown.

[0047] Figure 7 for Figure 2 A cross-sectional view of the adhesive spraying system in the device shown.

[0048] Among them, 1 is the connector, 2 is the outer shell, 3 is the powder inlet, 4 is the powder outlet, 5 is the powder chamber, 6 is the powder channel, 7 is the binder spraying channel, 8 is the spiral blade, 9 is the piezoelectric ceramic, 10 is the pulse control system, 11 is the diaphragm, 12 is the binder delivery pipe, 13 is the binder cavity, 14 is the binder cavity wall, 15 is the binder liquid outlet, and 16 is the nozzle core. Detailed Implementation

[0049] The present invention will be further described below with reference to embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0050] Example 1

[0051] like Figures 1-5 As shown, a coaxial adhesive spray nozzle includes a nozzle core 16, a housing 2, and a connector 1 connected above it for connecting to an external adhesive delivery system. The nozzle core has an adhesive spray channel 7. The cavity formed between the outer periphery of the adhesive spray channel 7 and the inner wall of the housing 2 is designated as a powder chamber 5 and a powder channel 6. A powder inlet 3 is opened on the upper outer wall of the housing 2, which is connected to the external powder delivery system. A powder outlet 4, which is sequentially connected to the powder chamber and powder channel, is provided at the lower end of the housing and the lower end of the nozzle core 16. During operation, the adhesive enters the adhesive spray channel of the nozzle core along the delivery system, while the powder is discharged through the powder outlet. Before being sprayed onto the substrate, the adhesive droplets and powder particles are fully and uniformly combined in the air under the driving force of the spray, and sprayed onto the substrate surface in the form of a mixture, improving the forming efficiency and effectively avoiding powder splashing.

[0052] like Figure 2 As shown, the adhesive spraying channel 7 is a through hole opened at the center of the nozzle core 16. The upper end of the through hole is a cylindrical hole and the lower end is a conical hole, which is used in conjunction with the piezoelectric adhesive spraying system.

[0053] like Figure 7As shown, the adhesive spraying channel is equipped with a piezoelectric adhesive spraying system, including a pulse control system 10, a piezoelectric ceramic 9, a diaphragm 11, an adhesive delivery pipe 12, and an adhesive cavity 13. During operation, the piezoelectric ceramic extends downward under the action of a pulse voltage signal, compressing the diaphragm below, thereby generating a pressure change in the adhesive cavity and causing the adhesive to be sprayed out from the nozzle.

[0054] like Figure 3 and Figure 4 As shown, the connector is a hollow open cylinder with internal threads, and a through hole at its center communicating with the adhesive delivery system and the adhesive spraying channel. The connector is a cylindrical protrusion integrally formed with the outer shell and the nozzle core.

[0055] The powder inlets are evenly distributed around the central axis of the nozzle. Preferably, the direction of the powder inlet through-hole is set along the radial direction of the nozzle core. The powder channel is a channel with a smooth inner wall, and the diameter of the channel gradually decreases from the powder cavity to the powder channel and then to the powder outlet.

[0056] The number of powder inlets is preferably 1 to 3, and in this embodiment there are 3; the wall thickness of the outer shell corresponding to the powder chamber is 2 to 3 mm, and in this embodiment it is 2 mm; the wall thickness of the nozzle core is 2 to 3 mm, and in this embodiment it is 2 mm; the wall thickness of the outer shell corresponding to the powder channel is 2 to 3 mm, and in this embodiment it is 2 mm.

[0057] Both the outer shell and the lower section of the nozzle core are inverted cones, forming a powder channel between the two cones; inside the powder chamber, the outer wall of the nozzle core is provided with helical blades. The helical blades are continuous ribbon helical blades.

[0058] Example 2

[0059] This embodiment uses the nozzle from Embodiment 1.

[0060] A method for uniform powder distribution in a coaxial powder feeding nozzle for adhesive spraying: The nozzle is provided with a powder inlet, and the powder feeding system is connected to the nozzle through the powder inlet to feed the powder into the powder chamber of the nozzle. The powder collides with the spiral blades and gradually achieves uniform distribution in the powder chamber by rebounding or flowing down the spiral. Finally, the powder is discharged through the powder channel along the powder outlet to achieve the purpose of uniform powder feeding.

[0061] The working principle of this embodiment is as follows: During processing, an external pulse control system inputs pulses. Under the action of the pulse voltage signal, the piezoelectric ceramic extends downwards, compressing the diaphragm below, thereby generating a pressure change in the binder cavity, causing the binder to be ejected from the nozzle; simultaneously, the molding powder enters the powder cavity through the powder inlet by an external powder feeding system, such as... Figure 6As shown, powder in the dir1 direction collides with the outer wall of the nozzle core. Since the outer wall of the nozzle core is a curved cylindrical surface, the powder will bounce in other directions, either bouncing off the inner wall of the outer shell and then falling into the powder channel, or bouncing off any of the spiral blades. The dir2 direction represents the powder colliding with the spiral blades. Some of the powder that collides with the spiral blades will be ejected directly and fall into the powder channel; some will go down the spiral and fly out from any radial angle of the nozzle under the action of centrifugal force. Moreover, the through hole of the powder inlet is perpendicular to the nozzle core, so that the powder is vertically fed into the powder chamber. At the same time, the powder enters the coaxial powder feeding nozzle of the binder spraying from the external powder feeding system. It has a certain initial velocity and will not fall instantly due to gravity. It will fill the entire powder chamber. Under the action of the inner wall of the outer shell, the outer wall of the nozzle core, and the spiral blades, it will move axially, radially, and circumferentially, and finally enter the powder channel, thereby achieving uniform distribution along the circumference of the powder outlet and achieving the effect of uniform powder discharge. The forming powder and the simultaneously sprayed micron-sized droplets of binder are fully mixed in the air and sprayed onto the substrate in the form of a mixture for forming.

[0062] Example 3

[0063] The device in this embodiment implements the method of embodiment two.

[0064] A coaxial powder feeding nozzle device for adhesive spraying includes a housing and a nozzle core located inside the housing. The upper side wall of the housing is provided with a powder inlet, which is connected to a powder feeding system. A powder chamber and a powder channel are provided between the inner side of the housing and the outer side of the nozzle core. A powder outlet is provided between the lower end of the housing and the lower end of the nozzle core. The powder inlet, powder chamber, powder channel, and powder outlet are interconnected. A spiral blade is provided on the outer side wall of the nozzle core.

[0065] Example 4

[0066] A method for manufacturing a coaxial adhesive spraying powder feeding nozzle, wherein the adhesive spraying coaxial powder feeding nozzle of Example 1 is manufactured.

[0067] The interface (dividing plane) is formed at the connection between the powder cavity and the powder channel. The part above the interface is preferably made of CuSn10 powder, which is sturdy, durable and relatively low in cost. The part below the interface is preferably made of Ti6Al4V powder, which is less likely to adhere to the binder or forming powder.

[0068] A method for manufacturing a coaxial powder feeding nozzle for adhesive spraying, characterized by comprising the following steps:

[0069] (1) Model drawing: In the 3D CAD software, according to the structural design of the coaxial powder feeding nozzle for adhesive injection, draw the 3D model of the coaxial powder feeding nozzle for adhesive injection. Set a dividing plane at the connection between the powder chamber and the powder channel. Save the upper and lower parts of the 3D model divided by the dividing plane as STL files and export them.

[0070] (2) Slicing process: Using slicing software, the upper and lower parts of the obtained three-dimensional model of the coaxial powder feeding nozzle for adhesive injection are sliced ​​and layered along the forming direction to obtain the slicing data of the model layer interface. Then, the slicing data files are imported into the 3D printing equipment.

[0071] (3) Rapid prototyping: Set the printing parameters on the host computer, use CuSn10 powder to print the part above the powder channel, then switch to Ti6Al4V powder and continue printing the remaining part of the nozzle;

[0072] (4) Post-treatment: Post-treatment of the formed adhesive spraying coaxial powder feeding nozzle;

[0073] (5) Install a piezoelectric adhesive spraying system.

[0074] In step (1), after the model is drawn, the three-dimensional model is analyzed in the three-dimensional CAD software to check whether there are any errors in the three-dimensional model of the coaxial powder feeding nozzle for adhesive spraying. After confirming that there are no errors, a dividing plane parallel to the XY plane is set at the connection between the powder chamber and the powder channel to divide the three-dimensional model into upper and lower parts, which will facilitate the use of different materials for manufacturing later.

[0075] In step (2), the two STL format files exported in step (1) are imported into the slicing software, and the placement of the parts is adjusted to keep the relative positions of the upper and lower coordinate systems unchanged.

[0076] In step (3), the rapid prototyping method is selective laser melting (SLM). First, CuSn10 powder is used to print part A above the powder channel. After printing is completed, the green blank is kept in the same position on the substrate. Then, the forming powder of the selective laser melting equipment is immediately replaced with Ti6Al4V powder, and the remaining part B of the nozzle is printed directly. Finally, the formed complete binder spraying coaxial powder feeding nozzle is taken out of the equipment.

[0077] In step (4), the post-processing process is as follows: remove the molding powder that is adhered to the surface of the adhesive spraying coaxial powder feeding nozzle or remains inside the nozzle, such as the powder cavity, powder channel, and spraying channel; polish and apply a nano-coating to the surface and interior of the adhesive spraying coaxial powder feeding nozzle to further reduce the adhesion between the nozzle and the adhesive and molding powder mixture and avoid nozzle clogging.

[0078] In step (5), the piezoelectric adhesive spraying system needs to be coaxially aligned with the adhesive spraying channel so that the liquid outlet and powder outlet are on the same horizontal plane.

[0079] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A coaxial powder feeding nozzle for adhesive spraying, characterized in that: The device includes a housing, a nozzle core, and a connector. The nozzle core is located inside the housing, and the connector is located above the housing. The nozzle core has an adhesive injection channel, which contains a piezoelectric adhesive injection system. The lower end of the nozzle core is the adhesive outlet. The inner wall of the housing and the outer wall of the nozzle core form a powder chamber and a powder channel. The housing has a powder inlet, and the lower end of the powder channel is the powder outlet. The powder inlet, powder chamber, powder channel, and powder outlet are connected in sequence. The adhesive injection channel is an axially oriented through-hole; the piezoelectric adhesive injection system includes a pulse control system, a piezoelectric ceramic, a diaphragm, an adhesive delivery pipe, and an adhesive cavity; the adhesive cavity is located in the lower section of the adhesive injection channel, and a through-hole is provided at the upper end of the adhesive cavity, with the diaphragm installed at this through-hole; the adhesive delivery pipe extends into the adhesive cavity; the pulse control system is connected to the piezoelectric ceramic, which is located directly above the diaphragm; the liquid adhesive outlet and the powder adhesive outlet are on the same horizontal plane. Both the outer shell and the lower section of the nozzle core are inverted cones, forming a powder channel between the two inverted cones; inside the powder chamber, the outer wall of the nozzle core is provided with spiral blades.

2. A coaxial powder feeding nozzle for adhesive spraying according to claim 1, characterized in that: The connector is a cylinder with internal threads, and a through hole communicating with the adhesive spraying channel is opened at the center of the connector.

3. A coaxial powder feeding nozzle for adhesive spraying according to claim 1, characterized in that: The outer shell, connector, and nozzle core are integrally formed; the outer shell and nozzle core are coaxially arranged, and the upper side wall of the outer shell has several powder inlets for connecting to an external powder feeding system. Each powder inlet is evenly distributed on the outer shell around the central axis of the nozzle core, and the axial direction of the powder inlet is set along the radial direction of the nozzle core.

4. A coaxial powder feeding nozzle for adhesive spraying according to claim 3, characterized in that: The number of powder inlets is 1 to 6; the wall thickness of the outer shell corresponding to the powder chamber is 2 to 3 mm; the wall thickness of the nozzle core is 2 to 3 mm; and the wall thickness of the outer shell corresponding to the powder channel is 2 to 3 mm.

5. A method for uniform powder distribution using a coaxial powder feeding nozzle for adhesive spraying, characterized in that: The adhesive spraying coaxial powder feeding nozzle as described in claim 1 is used; the powder feeding system conveys powder through the powder inlet, the powder enters the powder chamber along the powder inlet, the powder collides with the spiral blades, and through rebound or downward spiral, the powder gradually achieves uniform distribution in the powder chamber, and finally is discharged through the powder channel along the powder outlet, so as to achieve the purpose of uniform powder feeding.

6. A coaxial powder feeding nozzle device for adhesive spraying, achieving uniform powder distribution of the adhesive spraying coaxial powder feeding nozzle as described in claim 5, characterized in that: It includes a coaxial powder feeding nozzle for adhesive spraying and a powder feeding system, with the powder feeding system connected to the powder inlet.

7. A method for manufacturing a coaxial adhesive injection powder feeding nozzle, comprising the adhesive injection coaxial powder feeding nozzle according to any one of claims 1-4, characterized in that: A dividing plane is defined at the connection between the powder chamber and the powder channel. The dividing plane is set in the horizontal direction and divides the integrated molding structure of the shell, connector and nozzle core into upper and lower parts. The two parts are manufactured by rapid prototyping using different materials.

8. A method for manufacturing a coaxial powder feeding nozzle for adhesive spraying according to claim 7, characterized in that, Includes the following steps: (1) Model drawing: In the 3D CAD software, according to the structural design of the coaxial powder feeding nozzle for adhesive injection, draw the 3D model of the coaxial powder feeding nozzle for adhesive injection. Set a dividing plane at the connection between the powder chamber and the powder channel. Save the upper and lower parts of the 3D model divided by the dividing plane as STL files and export them. (2) Slicing process: Using slicing software, the upper and lower parts of the obtained three-dimensional model of the coaxial powder feeding nozzle for adhesive injection are sliced ​​and layered along the forming direction to obtain the slicing data of the model layer interface. Then, the slicing data files are imported into the 3D printing equipment. (3) Rapid prototyping: Set the printing parameters on the host computer, use CuSn10 powder to print the part above the powder channel, then switch to Ti6Al4V powder and continue printing the remaining part of the nozzle; (4) Post-treatment: Post-treatment of the formed adhesive spraying coaxial powder feeding nozzle; (5) Install a piezoelectric adhesive spraying system.

9. A method for manufacturing a coaxial powder feeding nozzle for adhesive spraying according to claim 8, characterized in that: In step (1), after the model is drawn, the three-dimensional model is first analyzed in the three-dimensional CAD software to check whether there are any errors in the three-dimensional model of the coaxial powder feeding nozzle for adhesive spraying. After confirming that everything is correct, set a dividing plane parallel to the XY plane at the connection between the powder chamber and the powder channel to divide the 3D model into upper and lower parts, save them as STL format files and then export them separately.

10. A method for manufacturing a coaxial powder feeding nozzle for adhesive spraying according to claim 8, characterized in that: In step (2), the two STL format files exported in step (1) are imported into the slicing software, the placement of the parts is adjusted, the relative positions of the upper and lower coordinate systems are kept unchanged, and slicing is performed to obtain the slicing data file.

11. A method for manufacturing a coaxial powder feeding nozzle for adhesive spraying according to claim 8, characterized in that: In step (3), the rapid prototyping method is selective laser melting (SLM). First, CuSn10 powder is used to print the part above the powder channel. After printing is completed, the green blank is kept in the same position on the substrate. Then, the forming powder of the selective laser melting equipment is immediately replaced with Ti6Al4V powder, and the remaining part of the nozzle is printed directly. Finally, the formed complete binder spraying coaxial powder feeding nozzle is taken out of the equipment.

12. A method for manufacturing a coaxial powder feeding nozzle for adhesive spraying according to claim 8, characterized in that: In step (4), the post-processing specifically involves: peeling the formed adhesive spraying coaxial powder feeding nozzle off the substrate, removing the formed powder from the surface of the adhesive spraying coaxial powder feeding nozzle or the powder cavity, powder channel, and spraying channel inside the nozzle, and polishing and nano-coating the surface and interior of the adhesive spraying coaxial powder feeding nozzle.

13. A method for manufacturing a coaxial powder feeding nozzle for adhesive spraying according to claim 8, characterized in that: In step (5), the piezoelectric adhesive spraying system needs to be coaxially aligned with the adhesive spraying channel so that the liquid outlet and powder outlet of the adhesive are on the same horizontal plane.

Images