A coaxial powder feeding nozzle for multi-material laser additive manufacturing and apparatus thereof

Abstract

The application discloses a coaxial powder feeding nozzle for multi-material laser additive manufacturing, comprising a hollow conical nozzle body provided with a laser channel, an inner powder feeding channel located in an inner ring and an outer powder feeding channel located in an outer ring are arranged on an upper end surface of the conical nozzle body, the inner powder feeding channel and the outer powder feeding channel are distributed in a circumferential array around a central axis of the conical nozzle body, an inclination angle of the inner powder feeding channel is smaller than that of the outer powder feeding channel, and powder flows of the two powder feeding channels converge at a same focal point at a lower end of the conical nozzle body. The application further discloses a coaxial powder feeding device for multi-material laser additive manufacturing. The application adds one powder feeding channel on the basis of a single powder feeding channel, has the function of double-channel delivery of heterogeneous powder, and provides higher operability for preparation of functionally graded materials, composite coatings and in-situ generated composite materials by laser additive manufacturing.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser additive manufacturing technology, and in particular to a coaxial powder feeding nozzle for multi-material laser additive manufacturing and a device thereof. BACKGROUND

[0002] Laser additive manufacturing technology is a new material forming and surface modification technology, which uses laser as a heat source, adds materials to the molten pool formed by laser heating according to a predetermined processing path through prepositioning or synchronous feeding, and makes the two co-solidify to form a cladding layer, which is then stacked on the substrate to realize the function of direct material forming or surface modification.

[0003] In the process of laser additive manufacturing, the powder material delivery is very important. Good delivery can reduce powder waste, improve powder utilization, and obtain a better isotropic cladding layer surface, which is smoother and more even. Therefore, the powder feeding system is a very important part of laser additive manufacturing technology, and the powder feeding nozzle, as one of the key components of the powder feeding system, directly affects the precision of the formed parts.

[0004] With the rapid development of industry, single material has been difficult to meet the actual production requirements of industry. The use of laser additive manufacturing technology to prepare functional gradient materials, composite coatings, and in-situ generated composite materials has become a new development trend. However, the current research on multi-material powder feeding is basically to pre-mix the powder and then use a single-channel powder feeding nozzle to achieve it. For a single-channel powder feeding nozzle, the mixed powder of multiple materials is difficult to maintain the predetermined proportion during the delivery process because the properties of various metal powders, especially the density and particle size, have a great influence on the powder delivery characteristics.

[0005] Frank Liou et al. of the University of Missouri Science and Technology found through experimental research that due to the differences in powder particle diameter and density, the powder mixture separates during the delivery from the powder feeder to the molten pool, which can lead to serious composition deviation in the deposited material. CN 105734560A discloses an eight-way coaxial powder feeding nozzle for double-layer gradient laser additive manufacturing, which adopts an inner four-way and outer four-way powder feeding channel distribution mode to realize one-time scanning forming of double-layer cladding layer during laser cladding, thereby improving the cladding efficiency. However, there is laser energy attenuation when the laser and the powder act, which makes it difficult to ensure consistent energy distribution between the upper and lower layers, and the nozzle is only suitable for preparing gradient materials, which cannot meet the requirements of laser additive manufacturing of functional gradient materials, composite coatings, and in-situ generated composite materials in multiple scene applications. In addition, the existing single-channel powder feeding nozzle is difficult to achieve accurate delivery and real-time adjustment of different materials for multi-material laser additive manufacturing. SUMMARY

[0006] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a multi-material laser powder feeding nozzle with high reliability and capable of realizing real-time adjustment of the delivery ratio of dissimilar materials and a device thereof.

[0007] The technical solution adopted by the present application to solve the technical problem is: a coaxial powder feeding nozzle for multi-material laser additive manufacturing, comprising a hollow conical nozzle body provided with a laser channel, an inner powder feeding channel located in an inner ring and an outer powder feeding channel located in an outer ring are arranged on an upper end surface of the conical nozzle body, the inner powder feeding channel and the outer powder feeding channel are distributed in a circumferential array around a central axis of the conical nozzle body, an inclination angle of the inner powder feeding channel is smaller than that of the outer powder feeding channel, and powder flows of the two powder feeding channels converge at a same focal point at a lower end of the conical nozzle body.

[0008] Further, the inner powder feeding channel comprises an inner powder inlet hole at the upper end and an inner annular gap channel at the lower end, the inner powder inlet hole is in communication with the inner annular gap channel, and a connecting section thereof is a circular arc transition connection, and a diameter of the circular arc is consistent with a diameter of the powder inlet hole.

[0009] Further, the outer powder feeding channel comprises an outer powder inlet hole at the upper end and an outer annular gap channel at the lower end, the outer powder inlet hole is in communication with the outer annular gap channel, and a connecting section thereof is a circular arc transition connection, and a diameter of the circular arc is consistent with a diameter of the powder inlet hole.

[0010] Further, an included angle between the inner annular gap channel and the central axis of the conical nozzle body is α1, and 10°≤α1<30°; an included angle between the outer annular gap channel and the central axis of the conical nozzle body is α2, and 10°<α2≤30°, wherein the included angle α2>the included angle α1.

[0011] Further, the inner powder inlet hole and the outer powder inlet hole are alternately distributed, and a plane formed by adjacent inner powder inlet holes and outer powder inlet holes and the central axis of the conical nozzle body has the same included angle.

[0012] Further, a width of the inner annular gap channel is d1, and 0.6mm≤d1≤1.5mm; a width of the outer annular gap channel is d2, and 0.6mm≤d2≤1.5mm.

[0013] Further, the conical nozzle body is provided with an annular water cooling cavity, the annular water cooling cavity is located between a wall surface of the conical nozzle body and the outer annular gap channel, and the annular water cooling cavity is provided with a water inlet and a water outlet at an upper end thereof.

[0014] Further, the inner powder feeding channel and the outer powder feeding channel are ring hole channels or a combination of ring hole channels and annular gap channels.

[0015] A coaxial powder feeding device for multi-material laser additive manufacturing, comprising a coaxial powder feeding nozzle for multi-material laser additive manufacturing.

[0016] Compared with the prior art, the present application has the following beneficial effects:

[0017] (1) The present application sets up multiple powder feeding channels independent of each other, adopts a powder feeding nozzle with double channels, and different powders pass through the powder feeding holes and the annular gap channels in turn, so that the powder beams converge to the center of the molten pool formed by laser irradiation, the flow rate and conveying quality of the different powders can be controlled independently, thereby adjusting the convergence characteristics of the powder flow and controlling the component ratio of the formed object.

[0018] (2) According to the numerical simulation calculation, the inner annular gap channel and the outer annular gap channel adopt different inclination angles, and the inclination angle of the outer annular gap channel is slightly lower than that of the inner annular gap channel, so that the different powders converge at the same focal point after passing through the annular gap channels, the powder focal spot diameter is smaller, and the forming efficiency is improved.

[0019] (3) The present application is provided with an annular water cooling cavity between the wall surface of the conical nozzle body and the wall surface of the outer annular gap channel, the upper end of the annular water cooling cavity is connected with a water inlet and a water outlet, the water cooling cavity is annular, the depth reaches one half of the depth of the nozzle body, the heat dissipation area is large, and the energy generated by laser irradiation can be dissipated efficiently.

[0020] (4) The lower end of the inner powder feeding hole and the outer powder feeding hole of the present application is a circular arc transition, which plays a role in the transition of the structure of the powder feeding hole and the annular gap channel, and the powder passes through the annular gap channel, so that the powder conveying is more continuous and uniform during the laser additive manufacturing powder feeding process.

[0021] (5) The inner powder feeding hole and the outer powder feeding hole of the present application are alternately distributed, the included angle between the adjacent inner powder feeding hole, the outer powder feeding hole and the central axis of the conical nozzle body is 45°, there is no structural conflict, and the connection between the powder feeder and the nozzle is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a three-dimensional structure schematic diagram of the multi-material laser additive manufacturing coaxial powder feeding nozzle of embodiment 1 of the present application.

[0023] Figure 2 is a working principle schematic diagram of the multi-material laser additive manufacturing coaxial powder feeding nozzle in embodiment 1 of the present application.

[0024] Figure 3 is a top view of the multi-material laser additive manufacturing coaxial powder feeding nozzle in embodiment 1 of the present application.

[0025] Figure 4 / Figure 5 / Figure 6 is a powder concentration numerical simulation cloud chart of different matching of alpha 1 and alpha 2 in embodiment 1 of the present application.

[0026] Figure 7is a three-dimensional structure schematic diagram of a multi-material laser additive manufacturing coaxial powder feeding nozzle of embodiment 2 of the present application.

[0027] Figure 8 is a top view of the multi-material laser additive manufacturing coaxial powder feeding nozzle in embodiment 2 of the present application.

[0028] Figure 9 is Figure 8 is a sectional view at A-A in FIG.

[0029] In the figure: 1, conical nozzle body; 2, laser channel; 3, inner powder feeding hole; 4, outer powder feeding hole; 5, inner annular gap channel; 6, outer annular gap channel; 7, annular water cooling cavity; 8, water inlet; 9, water outlet; 10, central axis; F, powder convergence focus point. DETAILED DESCRIPTION

[0030] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In addition, the terms "first", "second" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0031] In the description of the present application, it needs to be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0032] The present application will be further described in detail below in combination with the drawings and examples. Example 1

[0033] Referring to the drawings Figures 1-6The embodiment includes a hollow conical nozzle body 1, the center of the conical nozzle body 1 is provided with a laser channel 2, the upper end surface of the conical nozzle body 1 is provided with a plurality of inner powder inlet holes 3 and outer powder inlet holes 4, and the inner powder inlet holes 3 and the outer powder inlet holes 4 are arranged in a circumferential array around the central axis 10 of the conical nozzle body 1.

[0034] The inside of the conical nozzle body 1 is provided with an inner annular gap channel 5 and an outer annular gap channel 6, the upper ends of the inner annular gap channel 5 and the outer annular gap channel 6 are respectively connected and matched with the bottom ends of the inner powder inlet holes 3 and the outer powder inlet holes 4, and the end surfaces are connected in a circular arc transition connection.

[0035] The upper end surface of the inner powder inlet hole 3 and the outer powder inlet hole 4 is the powder inlet, and the lower end surface of the inner annular gap channel 5 and the outer annular gap channel 6 is the powder outlet. The powder is conveyed by the conveying pipeline and sequentially passes through the inner powder inlet hole 3 and the inner annular gap channel 5 and the outer powder inlet hole 4 and the outer annular gap channel 6.

[0036] In the embodiment, the number of inner powder inlet holes 3 and outer powder inlet holes 4 is 4, and the inner powder inlet holes 3 and the outer powder inlet holes 4 are arranged on different circumferences of the end surface of the conical nozzle body 1, and the inner powder inlet holes 3 and the outer powder inlet holes 4 are alternately distributed. Due to the different physical properties such as density of different types of powders, the alternately distributed setting can better realize the uniformity of the delivery of different types of powders.

[0037] The included angle between the adjacent inner powder inlet hole 3 and the outer powder inlet hole 4 and the plane formed by the central axis 10 of the conical nozzle body 1 is β, which is preferably 45° in the example. This is conducive to the installation and connection of the external powder feeding pipeline, and can also ensure the continuity and uniformity of the powder during the conveying process.

[0038] The included angles between the inner annular gap channel 5, the outer annular gap channel 6 and the central axis 10 of the conical nozzle body 1 are different, and the powder flows conveyed by the two annular gap channels converge at the same focal point F.

[0039] The width of the inner annular gap channel 5 is d1, and 0.6mm≤d1≤1.5mm, which is preferably 1mm in the embodiment; the width of the outer annular gap channel 6 is d2, and 0.6mm≤d2≤1.5mm, which is preferably 1mm in the embodiment.

[0040] The included angle α2 between the outer annular gap channel 6 and the central axis 10 of the conical nozzle body 1 is greater than the included angle α1 between the inner annular gap channel 5 and the central axis 10 of the conical nozzle body 1, wherein 10°≤α1<30° and 10°<α2≤30°.

[0041] Table 1 (powder convergence focal spot diameter and maximum concentration value matched with different α1 and α2)

[0042] .

[0043] Referring to the drawingsFigure 2 The simulation analysis is carried out by modeling, different angles α1 and α2 are taken respectively, and the simulation analysis is carried out in combination with Figure 4 Figure 5 Figure 6 and Table 1 can be obtained: when α1 and α2 are 20° and 30° respectively, the focal spot diameter is smaller and the convergence concentration is larger, so the heterogeneous powder has better convergence characteristics in the conveying process. When α1 and α2 are 10° and 20° respectively, although the focal spot diameter is smaller, the focal length is increased, and if the carrier gas speed is insufficient, the powder carrying capacity will be reduced, and it is difficult to ensure that the powder can still maintain good convergence characteristics after flowing out of the nozzle. Therefore, the most preferred angles in this embodiment are α1 = 20° and α2 = 30°.

[0044] The conical nozzle body 1 of this embodiment is additionally provided with a powder feeding channel on the basis of a conventional single powder feeding channel, and the center of the conical nozzle body 1 is provided with a conical hollow laser channel 2.

[0045] The heterogeneous powder enters the inner powder inlet hole 3 and the outer powder inlet hole 4 through the powder feeding pipeline connected with the powder feeder respectively, the powder inlet holes are connected with the annular gap channel through a circular arc transition, and the heterogeneous powder is output through the inner annular gap channel 5 and the outer annular gap channel 6 respectively, and is converged to the same position in the molten pool formed by laser irradiation through different trajectories, and is rapidly cooled and condensed to form a cladding layer.

[0046] The nozzle of this embodiment adopts a powder feeding nozzle with double channels, can be connected with different powder feeders, and can control the carrier gas flow and conveying quality of the heterogeneous powder separately, so as to adjust the convergence characteristics of the powder flow and control the component ratio of the formed part.

[0047] The conical nozzle body 1 is also provided with an annular water cooling cavity 7, which is located between the wall surface of the conical nozzle body 1 and the outer annular gap channel 6. The annular water cooling cavity 7 is connected with a water inlet 8 and a water outlet 9 at the upper end. The depth of the annular water cooling cavity 7 is half of the depth of the conical nozzle body 1, the heat dissipation area is large, and the high-efficiency heat dissipation is ensured. Embodiment 2

[0048] Referring to the accompanying drawings Figures 7-9 This embodiment includes a hollow conical nozzle body 1, the center of the conical nozzle body 1 is provided with a laser channel 2, the upper end surface of the conical nozzle body 1 is provided with a plurality of inner powder inlet holes 3 and outer powder inlet holes 4, and the inner powder inlet holes 3 and the outer powder inlet holes 4 are distributed in a circular array around the central axis 10 of the conical nozzle body 1.

[0049] ​​In the embodiment, the number of the inner powder feeding holes 3 and the outer powder feeding holes 4 is 4, the inner powder feeding holes 3 and the outer powder feeding holes 4 are arranged on the different circumferential rings of the end surface of the conical nozzle body 1, and the inner powder feeding holes 3 and the outer powder feeding holes 4 are alternately distributed at intervals. Due to the different physical properties such as the density of the heterogeneous powders, the alternately distributed arrangement at intervals can better realize the uniformity of the heterogeneous powder conveying.

[0050] The included angle between the adjacent inner powder feeding hole 3 and the outer powder feeding hole 4 and the plane formed by the central axis 10 of the conical nozzle body 1 is β, which is preferably 45° in the embodiment. In this way, it is beneficial for the installation and connection of the external powder feeding pipeline, and can also ensure the good continuity and uniformity of the powder in the conveying process.

[0051] The included angles between the inner powder feeding hole 3, the outer powder feeding hole 4 and the central axis 10 of the conical nozzle body 1 are different, and the powder flows conveyed by the two annular gap channels converge at the same focal point F.

[0052] The width of the inner powder feeding hole 3 is d1, and 0.6mm≤d1≤1.5mm, which is preferably 2mm in the embodiment. The width of the outer powder feeding hole 4 is d2, and 0.6mm≤d2≤1.5mm, which is preferably 2mm in the embodiment.

[0053] The included angle α2 between the outer powder feeding hole 4 and the central axis 10 of the conical nozzle body 1 is greater than the included angle α1 between the inner powder feeding hole 3 and the central axis 10 of the conical nozzle body 1, wherein 10°≤α1<30° and 10°<α2≤30°, and α1=20° and α2=30° are preferred in the embodiment.

[0054] Those skilled in the art can make various modifications and variations to the present application, and if these modifications and variations are within the scope of the claims of the present application and their equivalent technologies, they are still within the protection scope of the present application patent.

[0055] The contents not described in detail in the specification are the prior art known by those skilled in the art.

Claims

1. A coaxial powder feed nozzle for multi-material laser additive manufacturing comprising a hollow conical nozzle body provided with a laser channel, characterized in that: The upper end surface of the conical nozzle body is provided with an inner powder feeding channel located in the inner ring and an outer powder feeding channel located in the outer ring, the inner powder feeding channel and the outer powder feeding channel are distributed in a circumferential array around the central axis of the conical nozzle body, the inclination angle of the inner powder feeding channel is smaller than that of the outer powder feeding channel, and the powder flows of the two powder feeding channels converge at the same focal point at the lower end of the conical nozzle body; the inner powder feeding channel includes an inner powder inlet hole at the upper end and an inner annular gap channel at the lower end, the inner powder inlet hole is in communication with the inner annular gap channel, the connecting section is a circular arc transition connection, and the diameter of the circular arc is consistent with the diameter of the powder inlet hole; the outer powder feeding channel includes an outer powder inlet hole at the upper end and an outer annular gap channel at the lower end, the outer powder inlet hole is in communication with the outer annular gap channel, the connecting section is a circular arc transition connection, and the diameter of the circular arc is consistent with the diameter of the powder inlet hole; The included angle between the inner annular gap channel and the central axis of the conical nozzle body is α1=20°, and the included angle between the outer annular gap channel and the central axis of the conical nozzle body is α2=30°; the inner powder inlet hole and the outer powder inlet hole are alternately distributed, and the planes formed by the adjacent inner powder inlet hole and outer powder inlet hole and the central axis of the conical nozzle body have the same included angle.

2. The coaxial powder feed nozzle for multi-material laser additive manufacturing of claim 1, wherein: The width of the inner annular gap channel is d1, and 0.6mm≤d1≤1.5mm; the width of the outer annular gap channel is d2, and 0.6mm≤d2≤1.5mm.

3. The coaxial powder feed nozzle for multi-material laser additive manufacturing of claim 2, wherein: The conical nozzle body is provided with an annular water cooling cavity, the annular water cooling cavity is located between the wall surface of the conical nozzle body and the outer annular gap channel, and the annular water cooling cavity is provided with a water inlet and a water outlet at the upper end.

4. The coaxial powder feed nozzle for multi-material laser additive manufacturing of claim 1, wherein: The inner powder feeding channel and the outer powder feeding channel are ring hole channels or a combination of ring hole channels and annular gap channels.

5. A coaxial powder feed device for multi-material laser additive manufacturing, characterized by: A coaxial powder feeding nozzle for multi-material laser additive manufacturing according to any one of claims 1-4.

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