Powder feeding cover and laser additive wire and powder feeding device

Abstract

The application relates to a powder feeding cover and a laser additive wire and powder feeding device. The powder feeding cover is installed on a laser wire feeding assembly, a through hole for operation of the laser wire feeding assembly is arranged in the middle of the powder feeding cover, a plurality of powder feeding assemblies are arranged in the circumferential direction, a powder outlet of an inner side wall of the through hole extends to the inside of the cover to form a powder feeding channel which is inclined to a preset operation area, and each powder feeding channel is connected with a powder feeding assembly. The application solves the problems of large powder loss caused by powder scattering, fixed composition of wire feeding, and the like, greatly improves the utilization rate of powder materials, reduces the manufacturing cost, realizes flexible regulation and control of the composition of components, avoids defects such as non-fusion between layers, reduces dust pollution and explosion risk, and is suitable for efficient and high-quality manufacturing of complex components of high-end equipment.

Description

Technical Field

[0001] This application relates to the technical field of laser additive manufacturing, and in particular to a powder feeding cover and a device for simultaneously feeding laser additive filament and powder. Background Technology

[0002] Laser additive manufacturing technology, with its advantages of near-net-shape forming, manufacturability of complex structures, and high material utilization, has become a core technology for the rapid prototyping of complex components in aerospace, high-end equipment, and other fields. Its core principle is to melt and deposit filaments or powders as raw materials layer by layer using laser energy to ultimately form a complete component. The key lies in the coordinated control of raw material delivery and laser energy.

[0003] Currently, mainstream laser additive manufacturing technologies are mainly divided into two categories based on the form of raw materials: single-filament additive manufacturing and single-powder additive manufacturing. However, both have insurmountable technical defects in practical applications and cannot simultaneously meet the requirements for low-cost, high-performance, and high-quality component manufacturing.

[0004] Specifically, the advantages of single-wire additive manufacturing technology lie in its low cost, high material utilization, stable fluidity after filament melting, tight bonding between stacked layers, and high overall component density. However, its drawbacks are equally significant. The filament is a pre-formed, fixed component, making it impossible to flexibly adjust the material composition according to the performance requirements of different areas of the component, such as localized wear resistance, localized high-temperature resistance, or localized corrosion resistance. For example, it is difficult to achieve a composite performance of high strength in the matrix area and high wear resistance in the surface area on the same component. The filament has a certain degree of rigidity, and when printing complex structures such as thin walls and hollowed-out structures, the limited filament feeding path can easily lead to deviations in forming accuracy. Furthermore, the stacking morphology of a single filament after melting has low controllability, making it difficult to achieve fine forming of component details. Relying solely on the inherent properties of a single filament, it is impossible to improve the mechanical properties of the component by adding alloying elements or reinforcing phase powders, thus limiting its applicable scenarios.

[0005] The advantages of powder-feed additive manufacturing technology lie in its ability to mix powders of various compositions in a preset ratio, achieving precise customization of component material composition. Simultaneously, the powder's good flowability allows it to adapt to the precision molding requirements of complex components such as thin-walled and microstructured parts. However, its drawbacks severely restrict its industrial application. The fine powder particles are easily dispersed by airflow disturbances during pneumatic conveying, resulting in low actual utilization rates. Unused powder requires complex recycling processes such as screening and drying before reuse, increasing labor costs and wasting raw materials. Large amounts of dispersed powder easily adhere to the surface of molded components, forming dust contamination and reducing interlayer bonding strength. Uneven powder density can cause differences in laser energy absorption, easily leading to defects such as porosity and incomplete fusion, resulting in a high component scrap rate. Furthermore, large amounts of dispersed metal powder not only pollute the environment but also pose a dust explosion risk, requiring significant investment in building sealed dustproof workshops, increasing production costs.

[0006] In summary, there is an urgent need for a laser additive manufacturing technology solution that can integrate the advantages of wire feeding and powder feeding while minimizing their respective drawbacks. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of this application is to provide a powder feeding cover and a laser additive filament powder feeding device that can simultaneously meet the needs of low-cost, high-performance and high-forming quality component manufacturing.

[0008] The above-mentioned objective of this application is achieved through the following technical solution:

[0009] A powder feeding cover is installed on a laser wire feeding assembly. The cover has a through hole in its center for the laser wire feeding assembly to perform cladding operations. The cover is equipped with multiple powder feeding assemblies, which are spaced apart circumferentially along the through hole. Multiple powder outlets are formed on the inner wall of the through hole. Each powder outlet extends into the powder feeding cover to form a powder feeding channel. The end of each powder feeding channel away from the powder outlet is connected to a corresponding powder feeding assembly. All powder feeding channels are inclined towards the axis of the through hole, and their extension direction points towards a preset working area.

[0010] As a preferred embodiment of the present invention, the inner wall of the through hole is inclined outward along the direction of wire feeding of the laser wire feeding assembly.

[0011] As a preferred embodiment of the present invention, a water-cooled flow channel is provided between every two adjacent powder feeding channels inside the powder feeding hood.

[0012] A laser additive manufacturing filament powder feeding device includes the powder feeding cover described above, and also includes the laser filament feeding assembly. The laser filament feeding assembly is configured with a filament feeding channel and multiple laser generating devices. The multiple laser generating devices are arranged in a ring array with the filament feeding channel as the center line, and the multiple powder feeding channels are located outside the laser generating devices.

[0013] As a preferred embodiment of the present invention, the number of laser generating devices is odd, and the laser generating devices are not arranged at relatively opposite positions in the circumferential direction.

[0014] As a preferred embodiment of the present invention, each of the laser generating devices includes a plurality of laser generators.

[0015] As a preferred embodiment of the present invention, the number of laser generating devices is the same as the number of powder feeding channels, and each powder feeding channel is located between two adjacent laser generating devices.

[0016] As a preferred embodiment of the present invention, a water-cooling channel is provided on the outside of the wire feeding channel and inside each of the laser generating devices.

[0017] In summary, the beneficial technical effects of this application are as follows:

[0018] 1. This application significantly reduces powder loss and improves material utilization by setting a powder feeding channel inside the powder feeding hood to guide the powder into the molten pool. Furthermore, after the powder is output from the powder outlet, it directly and accurately flows into the molten pool formed by the laser along the inclined channel, avoiding the phenomenon that the powder is scattered by airflow disturbance due to the lack of constraint when feeding powder alone, thus reducing the powder loss that is wasted before reaching the molten pool.

[0019] 2. This application first uses a laser wire feeding assembly to perform the cladding operation to form a molten pool. The powder is directly fed into the high-temperature molten pool, instead of relying on the laser to melt it separately outside the molten pool. The heat of the molten pool itself can be used to quickly melt the powder, avoiding the loss of powder that has not been fully heated by the laser and becomes unmelted particles. The utilization rate of powder materials is greatly improved, and the waste of raw materials and manufacturing costs are significantly reduced.

[0020] 3. The filament fed by the filament feeding channel in this application serves as the basic skeleton for the molding of the printed parts, retaining the characteristics of low filament cost, stable and non-scattering feeding, and high material utilization, thus ensuring a reduction in the overall molding cost of the components. At the same time, the filament is uniformly heated and melted by multiple laser beams to form a stable molten pool, providing a high-temperature and uniform reaction field for subsequent powder mixing, thus avoiding component segregation caused by the instability of the molten pool when powder is fed alone.

[0021] 4. This application can flexibly transport powders of different compositions through the powder feeding channel. The powder directly enters the molten pool and mixes with the molten wire, realizing the control of the local or overall composition of the component, and solving the problem that the composition of the wire is fixed when feeding alone and cannot meet the customized performance.

[0022] 5. In this application, a stable molten pool is first formed by the wire and the laser, and then the powder is directly fed into the molten pool for mixing. This ensures that the wire and the powder are fully metallurgically bonded at high temperature, avoiding defects such as interlayer non-fusion and porosity caused by feeding powder before the molten pool is stable when feeding powder alone, and improving the density of the component.

[0023] 6. This application is based on filament material, and the amount of powder used is greatly reduced compared with pure powder feeding technology. While reducing costs and improving material utilization, it also greatly reduces the amount of powder scattered around, avoids dust pollution, reduces the risk of explosion, and significantly improves the safety of the working environment. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the main structure of the powder delivery cover.

[0025] Figure 2 This is a bottom view of the structure of the powder delivery cover.

[0026] Figure 3 This is a schematic diagram of the powder delivery cover.

[0027] Figure 4 for Figure 1 A sectional view cut along section AA.

[0028] Figure 5 This is a side view schematic diagram of the structure of a laser additive manufacturing filament and powder delivery device.

[0029] Figure 6 This is a schematic diagram of the structure of a laser additive manufacturing filament and powder delivery device.

[0030] Figure 7 This is a schematic diagram of a laser additive manufacturing wire and powder feeding device.

[0031] The reference numerals in the attached diagrams are as follows: 1. Powder feeding cover; 11. Through hole; 111. Powder outlet; 112. Powder feeding channel; 12. Powder feeding assembly; 13. Water cooling connector; 131. Water cooling inlet; 132. Water cooling outlet; 2. Laser wire feeding assembly; 21. Wire feeding channel; 22. Laser generator; 221. Laser generator; 23. Laser water cooling connector. Detailed Implementation

[0032] The present application will be further described in detail below with reference to the accompanying drawings.

[0033] like Figures 1-4 As shown, the structure of the powder feeding cover 1 is illustrated. The powder feeding cover 1 is mainly used in laser additive manufacturing scenarios where powder and filament are fed simultaneously, and is used in conjunction with the laser filament feeding assembly 2 to achieve precise powder delivery. The powder feeding cover 1 is installed entirely on the laser filament feeding assembly 2. Its installation method can adopt a conventional detachable connection structure in the field, such as fixing it to the corresponding mounting seat of the laser filament feeding assembly 2 with bolts, or achieving quick positioning and assembly through structures such as buckles and positioning pins, to ensure the relative position of the cover and the laser filament feeding assembly 2 is stable during operation.

[0034] A through hole 11 is provided in the middle of the powder feeding cover 1. This through hole 11 is the channel for the laser wire feeding assembly 2 to perform additive manufacturing operations, such as... Figure 4 As shown, the wire feeding channel 21 in the laser wire feeding assembly 2 guides the wire through the through hole 11 along the axial direction of the through hole 11. At the same time, the laser beam emitted by the laser wire feeding assembly 2 will also act on the wire and the area to be printed through the through hole 11. Therefore, the size of the through hole 11 needs to be compatible with the wire diameter and the effective range of the laser beam. The inner diameter of the through hole 11 is slightly larger than the sum of the wire diameter and the maximum effective width of the laser beam to avoid interference with the wire feeding and laser beam propagation.

[0035] To achieve powder conveying, the powder feeding hood 1 is equipped with multiple powder feeding components 12. These powder feeding components 12 are components that provide powder. Preferably, a pneumatic powder feeder is used, which uses compressed gas to drive the powder flow; more preferably, a screw powder feeder is used, which pushes the powder by rotating a screw. Each powder feeding component 12 is connected to an external powder storage device, such as a hopper, for continuously supplying the required powder. The powder feeding components 12 are distributed at intervals along the circumference of the through hole 11, and the distribution of the powder feeding components 12 can be uniformly arranged along the circumference of the through hole 11, such as... Figure 2 As shown, the three powder feeding components are arranged at 120-degree intervals.

[0036] On the inner sidewall of the through hole 11, there are powder outlets 111 corresponding to the number of powder feeding components 12. These powder outlets 111 are the outlets from which powder enters the through hole 11 from the powder feeding cover 1. Their shape can be designed as round, elliptical or rectangular according to the characteristics of the powder. The opening size is set according to the matching powder particle size and powder feeding amount, and is not limited again.

[0037] Each powder outlet 111 extends into the powder feeding hood 1 to form a powder feeding channel 112. These channels connect the powder outlet 111 with the powder feeding assembly 12. Preferably, the powder feeding channel 112 is a metal pipe embedded inside the hood. More preferably, the powder feeding channel 112 is a cavity machined directly in the solid structure of the hood as a channel, and the inner wall of the channel is smoothed to reduce resistance and residue during powder conveying.

[0038] Each powder feeding channel 112 is connected to the corresponding powder feeding component 12 at the end away from the powder outlet 111. The connection is sealed through a pipe joint to ensure that the powder can be stably conveyed from the powder feeding component 12 to the powder outlet 111 via the powder feeding channel 112.

[0039] It is worth noting that multiple powder feeding channels 112 are inclined towards the axis of the through hole 11, that is, the extension direction of the channel forms a certain angle with the axis of the through hole 11. See Figures 2-4 If the axis of the through hole 11 is set to point in the up and down direction, the powder feeding channel 112 will transport the powder in the downward direction. The extension direction of all powder feeding channels 112 will eventually point to the preset working area. The preset working area is the location of the molten pool formed by the interaction between the laser beam and the wire in the laser wire feeding assembly 2. Through this inclined design, after the powder is ejected from the powder outlet 111, it can accurately flow into the molten pool under the guidance of the channel, reducing the dispersion due to lack of restraint, thereby achieving efficient mixing of powder and molten wire.

[0040] Further, see Figure 4As shown, the inner wall of the through hole 11 of the powder feeding cover 1 is inclined outward along the conveying direction of the filament in the laser filament feeding assembly 2. That is, from the end of the powder feeding cover 1 that is close to the laser filament feeding assembly 2 to the end that is far away from the laser filament feeding assembly 2, the inner wall of the through hole 11 gradually inclines away from the axis of the through hole 11, so that the through hole 11 as a whole has a trumpet-shaped structure that gradually expands along the conveying direction of the filament.

[0041] The inclined design of the inner wall of the through hole 11 allows a suitable angle to be formed between the inner wall of the through hole 11 and the powder outlet 111 opened thereon. Preferably, the axis of the powder outlet 111 is perpendicular to the inner wall of the through hole 11. This significantly reduces the processing difficulty of the powder outlet 111 and the connected powder feeding channel 112. Since the inclined surface provides a flat opening reference for the powder outlet 111, the powder outlet 111 can be formed directly by drilling or milling along the direction perpendicular to the inclined surface during processing. This not only reduces burrs and debris generated during processing and ensures the smoothness of the inner wall of the powder feeding channel 112, but also makes the connection between the powder feeding channel 112 and the powder outlet 111 smoother and avoids powder accumulation in the channel. At the same time, the design of the powder outlet 111 perpendicular to the inclined surface and the powder feeding channel 112 inclined towards the axis of the through hole 11 allows the initial direction of the powder sprayed from the powder outlet 111 to be more accurately directed to the preset working area, reducing powder scattering caused by the deflection of the powder discharge direction and further improving the powder feeding directionality.

[0042] The through-hole 11 expands outward along the wire feeding direction, providing more space for wire feeding, laser action, and the flow of protective gas. If the wire deviates slightly due to minor vibrations during feeding, the expanded through-hole 11 can prevent the wire from rubbing against the inner wall, ensuring the stability of wire feeding. As the laser beam emitted by the laser wire feeding assembly 2 propagates to the working area, the expanded through-hole 11 reduces the obstruction of the laser by the inner wall, ensuring that the laser energy is more concentrated on the end of the wire and the area to be printed. In addition, the expanded structure also facilitates the smooth flow of protective gas in the through-hole 11, allowing the gas to cover the molten pool area more efficiently and reducing the oxidation effect of air on the molten pool.

[0043] Inside the powder feeding hood 1, a water-cooled flow channel is provided between every two adjacent powder feeding channels 112. These flow channels are closed cavities or pipe structures used for the flow of cooling media such as deionized water and industrial coolant. Figure 2As shown, a water-cooled connector 13 is provided between each pair of adjacent powder feeding channels 112. The water-cooled connector 13 includes a water-cooled inlet 131 and a water-cooled outlet 132. The cooling medium flows through the water-cooled inlet 131 and the water-cooled outlet 132 in the water-cooled flow channel between them. Preferably, a continuous flow channel cavity is formed by milling or drilling inside the cover body, and then the opening is sealed by sealing plugs, welding, or other methods, leaving only the inlet and outlet. The inlet and outlet are connected to the water-cooled inlet 131 and the water-cooled outlet 132, respectively, and then further connected to the external cooling system to form a closed-loop flow path for the cooling water.

[0044] The core purpose of this water-cooled flow channel is to efficiently cool the powder feeding hood 1 and the powder feeding channel 112. During laser additive manufacturing, the powder feeding hood 1 is located close to the laser action area. The heat radiation from the laser and the high-temperature conduction from the molten pool will cause the temperature of the hood to rise continuously. At the same time, although the powder flowing in the powder feeding channel 112 does not directly contact the high-temperature molten pool, it is in a near-high-temperature environment for a long time. If the temperature of the hood and the channel is too high, it may cause two problems: First, the powder feeding hood 1 will deform due to thermal expansion and contraction, thereby changing the tilt angle of the powder feeding channel 112 and the relative position of the powder outlet 111, which will damage the accuracy of powder delivery and affect the confluence effect of powder and molten pool. Second, the high temperature may cause the temperature of the inner wall of the powder feeding channel 112 to rise, causing the powder to clump together due to heat in the channel, blocking the channel or causing fluctuations in the powder delivery rate.

[0045] The water-cooled flow channel between adjacent powder feeding channels 112, through continuous circulation of cooling medium, can quickly remove heat from the cover and the surrounding area of ​​the channel, stabilizing the operating temperature of the powder feeding cover 1 within a preset range. This not only avoids structural precision loss due to high-temperature deformation of the cover, ensuring that the powder feeding channel 112 always maintains the preset tilt angle and directionality, guaranteeing stable and accurate powder delivery to the molten pool; it also prevents powder agglomeration caused by excessively high inner wall temperature of the powder feeding channel 112, maintaining smooth and stable powder feeding. In addition, a stable temperature environment can also extend the service life of the powder feeding cover 1, reduce the frequency of component replacement due to high-temperature aging, and lower equipment maintenance costs.

[0046] See Figures 5-7 The present invention illustrates a laser additive filament powder feeding device, including the aforementioned powder feeding cover 1 and laser filament feeding assembly 2, which are assembled into a whole through a suitable mounting structure to ensure that the relative positions of each component are accurate and stable during operation.

[0047] The laser wire feeding assembly 2 is a component that realizes wire feeding and laser energy supply. It is equipped with a wire feeding channel 21 and multiple laser generators 22. The wire feeding channel 21, serving as the path for wire feeding, is typically made of a high-temperature resistant and wear-resistant metal conduit. The inner diameter of the conduit is slightly larger than the wire diameter to reduce frictional resistance during wire feeding and prevent wire swaying. The wire feeding channel 21 is connected to an external wire feeding mechanism. The external wire feeding mechanism drives the wire through the wire feeding channel 21 to extend towards the preset working area, ensuring that the wire is stably fed along the axial direction of the through-hole 11 to the area to be printed. Figure 4 As shown, the internal path of the wire feeding nozzle in the laser wire feeding assembly 2 is part of the wire feeding channel 21, which extends into or even penetrates the through hole 11.

[0048] Furthermore, multiple laser generating devices 22 are arranged in a ring array with the wire feeding channel 21 as the center line. Specifically, these laser generating devices 22 are evenly distributed or at preset intervals around the outer periphery of the wire feeding channel 21. Preferably, three laser generating devices 22 are distributed at 120° intervals, forming a ring-shaped energy supply structure surrounding the wire. Preferably, the laser generating devices 22 are fiber lasers or semiconductor lasers commonly used in the art. After being adjusted by a focusing lens group, their output laser beams can be precisely focused on the intersection of the wire end and the area to be printed. The advantage of this ring array layout is that multiple laser beams can act evenly on the wire from different directions, avoiding local overheating or uneven melting of the wire caused by a single laser beam or asymmetrical laser distribution, ensuring that the wire forms a stable temperature and regular shaped molten pool under the action of laser energy.

[0049] It is worth noting that the multiple powder feeding channels 112 on the powder feeding cover 1 are arranged on the outside of the laser generating device 22. That is, from the radial direction of the device, the innermost layer is the wire feeding channel 21, the middle layer is the ring-shaped array of laser generating devices 22, and the outermost layer is the powder feeding channel 112. This three-layer radial layout, with the wire feeding channel 21 in the center, the laser generating device 22 arranged in the center and the powder feeding channel 112 arranged in the outer ring, forms a collaborative working structure with the wire inside, the laser surrounding, and the powder outside. The inner wire melts under the action of the laser to form a molten pool. The laser in the middle layer provides continuous and uniform energy to the molten pool, while the outer powder feeding channel 112 accurately pushes the powder to the molten pool along a preset path. It should be further stated here that the powder feeding channel 112 does not point to the laser convergence point, but to the already formed molten pool. This avoids the channel overheating caused by direct laser irradiation of the powder feeding channel 112, and reduces the risk of the powder being preheated by the laser during the transportation process and oxidizing or agglomerating. At the same time, it ensures that the powder can smoothly enter the high-temperature molten pool and mix with the melted wire under the indirect action of the laser energy, so as to achieve efficient metallurgical bonding of wire and powder.

[0050] Furthermore, in this laser additive filament feeding device, the number of laser generators 22 is set to an odd number, and when these laser generators 22 are distributed circumferentially, no other laser generators 22 are placed at any position relative to one laser generator 22 on the circumference, i.e., at a position symmetrical to the axis of the filament feeding channel 21. This layout design is mainly aimed at addressing the problem of backlight interference in laser additive manufacturing, and can effectively protect the laser generators 22 and extend their service life.

[0051] Specifically, when the laser generator 22 is working, the laser beam it emits is focused on the end of the filament and the area to be printed. When the laser interacts with the filament, the molten pool, or the surface of the workpiece, it inevitably produces some reflected light, i.e., backlight. If this backlight directly enters the interior of other laser generators 22, especially the optical lens or the core components of the laser generator 221, it will cause significant damage. For example, the energy of the backlight may cause the lens coating to age or burn out, or cause the resonant cavity or semiconductor chip inside the laser generator 221 to overheat and fail, severely shortening the service life of the laser generator 22, or even causing equipment failure.

[0052] This risk is mitigated when the number of laser generators 22 is odd and there are no other devices in the circumferential relative position, such as... Figures 5-7 As shown, taking three laser generators 22 as an example, they are distributed at 120° intervals along the circumference of the wire feeding channel 21. In this case, the opposite side of each laser generator 22, or its relative circumferential position, is the gap between two devices, not another laser generator 22. Therefore, the reflected light generated by this device will scatter towards the gap area opposite, and cannot penetrate into the interior of other laser generators 22, thus avoiding damage to other devices.

[0053] Meanwhile, this odd-numbered distribution does not affect the uniformity of laser energy. Multiple laser generators 22 surround the wire feeding channel 21 from different circumferential angles, and the laser beams emitted by them can still converge on the end of the wire from multiple directions, ensuring uniform heating of the wire and forming a stable molten pool. Therefore, this design, while ensuring the effectiveness of the laser action, significantly improves the operational stability and service life of the device by avoiding direct irradiation of the laser generators 22 by backlighting, and reduces equipment maintenance costs.

[0054] However, the odd number of laser generating devices 22 does not mean that only an odd number of lasers can be used for processing. Furthermore, when the number of laser generators 221 within each laser generating device 22 is even, combined with the odd number of laser generating devices 22, the total number of lasers in the entire device can be even. For example, three laser generating devices 22 each contain two laser generators 221, for a total of six. This satisfies special working conditions requiring an even number of lasers for processing. Moreover, this design does not change the core layout where there are no laser generating devices 22 in the circumferentially opposite positions. While increasing the number of lasers, the reflected light generated will still scatter towards the circumferentially opposite gaps, preventing it from entering other laser generating devices 22. Therefore, it can continue to maintain the effect of avoiding reflected light, protecting the laser generators 221 from damage.

[0055] Furthermore, the number of laser generators 22 is consistent with the number of powder feeding channels 112, see [reference]. Figure 5 As shown, when there are 3 laser generating devices 22, there are also 3 powder feeding channels 112; and in the circumferential distribution of the device, each powder feeding channel 112 is arranged between two adjacent laser generating devices 22, forming an alternating arrangement structure of laser generating devices 22 and powder feeding channels 112.

[0056] When adjacent laser generators 22 are working, the laser beams they emit will form a relatively stable energy transition region between them. The powder feeding channel 112 is located in this region. After the powder is output from the channel, it can avoid being directly irradiated by the strong energy of a single laser generator 22, preventing the powder from melting and clumping or oxidizing in advance. It can also make full use of the energy radiation of the lasers on both sides, so that the powder is preheated appropriately during the process of being transported to the molten pool. After entering the molten pool, it can mix with the molten wire more quickly, reducing stress defects caused by excessive temperature difference between the powder and the molten pool.

[0057] From the perspective of powder delivery uniformity, the alternating distribution of the same number of laser generators 22 and powder delivery channels 112 can form a circumferentially uniform energy and powder synergy ring around the filament delivery channel 21. Taking three sets of laser generators 22 and three powder delivery channels 112 as an example, the laser generators 22 and powder delivery channels 112 are arranged alternately at 60° intervals in the circumferential direction. The powder is uniformly fed into the molten pool from three directions, avoiding uneven powder distribution and component segregation in the molten pool caused by unilateral or non-uniform circumferential powder delivery. At the same time, the energy density of the energy transition area corresponding to each powder delivery channel 112 is similar, which can ensure that the powder delivered by different channels is in a consistent preheated state before entering the molten pool, further improving the uniformity of material mixing in the molten pool, and ultimately ensuring the consistency of composition and mechanical property stability of the printed layer.

[0058] In addition, this design simplifies the assembly and debugging process of the device. Since the number of laser generators 22 and powder feeding channels 112 correspond and their positions alternate, the installation coordinates of the powder feeding channels 112 can be directly determined through the gap of the laser generators 22 during installation, without the need to set up a complex positioning structure. During the debugging phase, only the energy output of the laser generators 22 needs to be adjusted to simultaneously optimize the powder preheating effect of the corresponding powder feeding channels 112, reducing the workload of debugging channels and lasers separately and improving the overall debugging efficiency of the device.

[0059] Furthermore, to cope with the high temperature during operation, water-cooled cooling channels are configured on the outside of the wire feeding channel 21 and inside each laser generating device 22. Multiple laser water-cooled connectors 23 are formed on the laser wire feeding assembly 2 to connect with the external cooling circulation system. Both types of water-cooled cooling channels adopt closed cavity or pipe structures and can be connected to the external cooling circulation system through pipelines to achieve continuous circulation of the cooling medium to efficiently remove heat.

[0060] Furthermore, considering the arrangement of the laser generator 22 between the two powder feeding channels 112, specifically, with the wire feeding channel 21 as the center, the laser generator 22 is located radially outside the wire feeding channel 21 and inside the powder feeding channel 112, and each laser generator 22 is correspondingly embedded in the gap between two adjacent powder feeding channels 112. A water-cooling channel is provided between the two powder feeding channels 112. Therefore, the laser generator 22 corresponds one-to-one with the water-cooling channel, and the water-cooling channel is arranged on the outside of the laser generator 22. This arrangement allows the water-cooling channel to cool the wire feeding channel 21 while also cooling the laser generator 22 due to the positional correspondence. Similarly, the water-cooling channel can also cool the laser generator 22 while also cooling the wire feeding channel 21 due to the positional correspondence, thus maximizing the cooling effect of the cooling structure.

[0061] A laser additive manufacturing filament feeding method is implemented using the aforementioned laser additive manufacturing filament feeding device. Each step is deeply coordinated with the device structure to achieve efficient and high-quality component printing. The specific operation process is as follows.

[0062] First, perform step S1, which is to adjust the relative position of the laser additive filament feeding device and the substrate to be printed, so that the through hole 11 in the middle of the powder feeding cover 1 on the device is precisely aligned with the area to be printed on the surface of the substrate.

[0063] Next, in step S2, the filament is fed through the filament feeding channel 21 of the device. The filament feeding process is driven by an external filament feeding mechanism, which controls the filament feeding speed to match the rhythm of the subsequent molten pool formation, so that the end of the filament slowly approaches the area to be printed that was aligned in step S1. At the same time, multiple laser generating devices 22 on the device are activated. These laser generating devices 22 are arranged in an odd-numbered ring array with the filament feeding channel 21 as the center line, and there are no other devices in the circumferential relative positions, which can effectively avoid damage to the laser head by backlight. After activation, multiple laser beams are focused by their respective optical systems and finally converge at the intersection of the filament end and the area to be printed. The high heat of the laser melts the end of the filament and forms a molten pool with a stable temperature and regular shape together with the thin layer of material on the surface of the area to be printed. At this time, the water cooling system needs to be activated simultaneously to cool down the filament feeding channel 21 and the laser generating devices 22 to avoid high temperature affecting the stability of filament feeding or the life of the laser generating devices 22.

[0064] Then, in step S3, after the molten pool has stabilized, a preset powder is pushed into the molten pool through multiple powder feeding channels 112 on the outside of the device. These powder feeding channels 112 are the same number as the laser generating devices 22 and are alternately distributed between adjacent laser generating devices 22. After the powder is output from the powder feeding assembly 12, it flows along the inclined path of the powder feeding channel 112, and is precisely ejected through the powder outlet 111 on the inner side wall of the through hole 11 of the powder feeding cover 1, ultimately flowing directly into the high-temperature molten pool. After entering the molten pool, the powder quickly mixes with the molten wire to form a uniformly shaped molten material.

[0065] Finally, step S4 is executed, controlling the laser additive filament feeding device to move relative to the substrate along the preset printing path. This allows the laser additive filament feeding device to move while the substrate is fixed, or vice versa. The preset printing path is generated based on the 3D model of the component to be printed, encompassing the component's outline shape and infill trajectory. During the relative movement, the molten pool formed in step S2 extends forward in the direction of movement, while the molten material behind it rapidly cools and solidifies under the influence of ambient temperature and substrate heat dissipation, forming a dense printed layer. As the movement continues, new molten pools continuously form at the edges of the already formed printed layers, and the heat from these new pools slightly melts the surface of the already formed printed layers, ensuring a strong metallurgical bond between adjacent printed layers and preventing interlayer fusion defects. This process is repeated, stacking printed layers one by one to ultimately form a complete component that meets the design dimensions and performance requirements.

[0066] In a preferred embodiment, in step S3 of this laser additive filament powder feeding method, the powder pushed in each powder feeding channel 112 contains at least two different components. That is, a single powder feeding channel 112 does not transport a single component powder, but rather a multi-component composite powder pre-mixed in a preliminary ratio. For example, one powder feeding channel 112 may simultaneously contain tungsten carbide powder for increasing hardness and nickel-cobalt alloy powder for improving toughness, while another powder feeding channel 112 may simultaneously contain chromium powder for enhancing corrosion resistance and copper powder for adjusting melting point. Before entering the powder feeding channel 112, these multi-component powders are temporarily stored in the dispensing mechanism of the powder feeding assembly 12. This dispensing mechanism can employ a twin-screw mixing structure or a multi-bin precision dispensing structure, enabling independent control of the conveying amount of different component powders within the same channel, thereby achieving dynamic adjustment of the powder mixing ratio within the channel.

[0067] Specifically, when adjusting the proportion of different powder components in each powder feeding channel 112, it is not necessary to change the number of powder feeding channels 112 or the corresponding powder types. This can be achieved simply by adjusting the working parameters of the powder feeding component 12's dispensing mechanism. In a preferred embodiment, for a powder feeding channel 112 containing tungsten carbide and nickel-cobalt alloy powders, if it is necessary to improve the wear resistance of the printed layer, the conveying rate of tungsten carbide powder in the dispensing mechanism can be increased, while the conveying rate of nickel-cobalt alloy powder can be decreased, so that the mixing ratio of the two powders in the channel is adjusted from the initial 4:6 to 6:4. If it is necessary to take into account toughness, the opposite adjustment is made, reducing the tungsten carbide powder rate and increasing the nickel-cobalt alloy powder rate, so that the mixing ratio is biased towards the toughness component.

[0068] When these multi-component powders, mixed in adjusted proportions, are conveyed along an inclined path through the powder feeding channel 112 to the powder outlet 111, they are precisely drawn into the high-temperature molten pool under the guidance of the channel, where they rapidly undergo metallurgical bonding with the molten filament. Because the proportions of different powder components within the same powder feeding channel 112 are precisely controlled, the percentage of each component in the molten pool can be stably maintained within a preset range. For example, the aforementioned mixture of tungsten carbide and nickel-cobalt alloy powder, after bonding with the filament matrix in the molten pool, increases the proportion of tungsten carbide in the printed layer, thus improving the Vickers hardness of the printed layer; conversely, increasing the proportion of nickel-cobalt alloy optimizes the impact toughness of the printed layer. This method of adjusting the proportions of multi-component powders within a single channel allows for flexible control of the composition and performance of the printed layer without altering the layout of the powder feeding channel 112 or adding additional powder feeding components 12. It is particularly suitable for scenarios with precise requirements for the performance of localized areas, simplifying equipment operation and enabling precise customization of printed layer performance.

[0069] In another preferred embodiment, in step S3 of this laser additive filament powder feeding method, the powders pushed in different powder feeding channels 112 are all single-component materials that are different from each other. That is, each powder feeding channel 112 is only for conveying a specific type of powder. For example, channel 1 is specifically for conveying tungsten carbide powder to improve the wear resistance of the printed layer, channel 2 is specifically for conveying chromium-nickel alloy powder to enhance corrosion resistance, and channel 3 is specifically for conveying titanium alloy powder to optimize mechanical strength. The powder composition of each channel is determined in advance according to the preset performance requirements of the component to be printed, and is adapted to the powder feeding assembly 12 through an independent powder storage device to avoid mixing of different powder components before conveying.

[0070] When powders of different compositions are fed through their respective powder feeding channels 112 from the powder outlet 111 and into the high-temperature molten pool at the adjusted powder feeding speed and ratio, they rapidly undergo metallurgical bonding with the molten filament. For example, tungsten carbide powder can be uniformly dispersed in the molten matrix to form a hard reinforcing phase; chromium-nickel alloy powder can form a solid solution with the matrix, improving corrosion resistance; and titanium alloy powder can optimize the crystal structure of the matrix, enhancing tensile strength. By precisely controlling the powder feeding speed and ratio of each channel, the mixing ratio of different components in the molten pool can be stably maintained within a preset range, such as 15% tungsten carbide, 25% chromium-nickel alloy, 10% titanium alloy, and 50% filament matrix. After the molten material cools and solidifies to form a printing layer, the printing layer possesses the preset performance matched to the component ratio.

[0071] This design, where each powder feeding channel 112 delivers a different single-component powder, offers greater flexibility and precision compared to single-component powder feeding or pre-mixed powder within the channels. If the performance of the printed layer needs adjustment, simply increasing the powder feeding speed of the channel containing the tungsten carbide powder will increase its proportion in the molten pool, without altering the parameters of other channels. Furthermore, to address the differentiated performance requirements of different areas of the component, such as high wear resistance for the surface layer and high toughness for the internal layer, the powder feeding speed and proportion of each channel can be dynamically adjusted during printing to achieve gradient changes in the performance of the printed layer. This overcomes the technical limitations of fixed additive manufacturing components and single-performance characteristics associated with single-feed filament feeding, significantly expanding the application scenarios of laser additive components.

[0072] It is worth noting that during the laser additive manufacturing process, the laser additive filament feeding device moves relative to the substrate along a preset printing path. This preset printing path is generated by slicing software from the 3D model of the component to be printed, encompassing parameters such as the contour trajectory and infill density for each layer. The movement method can be flexibly selected according to the equipment type; either the substrate can be fixed and the device can be driven to move along the path, or the device can be fixed and the substrate can be driven to translate along the path, ensuring that the relative position of the device and the substrate accurately matches the printing requirements of each layer. As the relative movement continues, the molten pool formed by the device will continuously generate new molten areas as the path extends, while the molten material already formed behind will quickly cool and solidify, thus accumulating into a complete printing layer. After one layer is printed, the device or substrate will move a preset distance perpendicular to the printing layer, i.e., the thickness of the just-completed printing layer, and then begin printing the next layer. Through this layer-by-layer cycle, the overall forming of the component is finally achieved.

[0073] The key is that the filament feeding and powder feeding processes in each layer of printing can be independently controlled without interference. The independent control of filament feeding means that the filament delivery speed and amount in the filament feeding channel 21 can be adjusted individually according to the thickness and structural strength requirements of different printed layers. For example, when printing a thick-walled support layer, the filament delivery speed can be increased to increase the proportion of filament in that layer, thereby strengthening the load-bearing capacity of the support layer; while when printing a thin-walled functional layer, the filament delivery speed can be reduced to decrease the amount of filament used, avoiding excessive layer thickness that could affect component accuracy. As the basic framework for each printed layer, the independent control of the filament ensures that each layer has stable structural strength, providing reliable matrix support for subsequent powder mixing and performance optimization.

[0074] Independent powder feeding control is achieved through differentiated delivery via multiple powder feeding channels 112. Each layer can have its powder composition, feeding speed, and feeding ratio adjusted individually according to its performance requirements. For example, when printing the inner layer of a component, to improve overall impact resistance, nickel-based alloy powder with better toughness can be fed through the powder feeding channel 112, and the feeding ratio of this powder can be increased. When printing the middle layer, to balance strength and toughness, chromium-molybdenum alloy powder can be switched to. When printing the outer layer, to enhance surface wear resistance, tungsten carbide composite powder can be switched to. This layer-by-layer independent powder control allows the component to form a gradient structure with gradually changing performance from the inner to the outer layer. For example, the inner layer is impact-resistant, the middle layer is strong and tough, and the outer layer is wear-resistant, or a smooth transition from high-temperature resistance to corrosion resistance can be achieved from one end to the other, completely breaking through the limitation of uniform performance across the entire size of components in traditional laser additive manufacturing technology.

[0075] This layer-by-layer, independently controlled, and gradient performance shaping processing method significantly expands the application scenarios of laser additive manufacturing. For example, in the aerospace field, it can be used to manufacture engine blades. The blade root requires high strength to bear the load, which can be achieved by using multiple filaments as a base layer combined with high-strength powder. The blade tip requires high temperature resistance and oxidation resistance, which can be achieved by using fewer filaments as a base layer combined with high-temperature alloy powder, thus meeting the differentiated performance requirements of different parts of the blade. For example, in the medical field, it can be used to manufacture artificial joints. The inner layer connecting the joint and bone needs mechanical properties similar to human bone tissue, which can be achieved by mixing filaments with biocompatible powders in a low proportion. The joint surface needs high wear resistance to extend its service life, which can be achieved by using a high proportion of wear-resistant ceramic powder. For example, in the construction machinery field, it can also be used to manufacture excavator bucket teeth. The bucket tooth body needs high toughness to resist fracture, which can be achieved by using multiple filaments combined with tough alloy powder. The bucket tooth cutting edge needs high hardness to resist wear, which can be achieved by using fewer filaments combined with high-hardness alloy powder. In these scenarios, traditional single wire or powder feeding technologies cannot achieve gradient performance and are difficult to meet complex usage requirements. However, the technical solution of this application can be precisely adapted, promoting the extension of laser additive manufacturing to the field of more complex and high-end component manufacturing.

[0076] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A powder feeding cover, characterized in that, The powder feeding cover (1) is installed on the laser wire feeding assembly (2), and a through hole (11) is provided in the middle for the laser wire feeding assembly (2) to perform cladding operation. The powder feeding cover (1) is equipped with a plurality of powder feeding assemblies (12), and each powder feeding assembly (12) is distributed circumferentially at intervals along the through hole (11). A plurality of powder outlets (111) are provided on the inner sidewall of the through hole (11). Each powder outlet (111) extends into the powder feeding cover (1) to form a powder feeding channel (112). The end of each powder feeding channel (112) away from the powder outlet (111) is connected to the corresponding powder feeding assembly (12). The plurality of powder feeding channels (112) are all inclined toward the axis of the through hole (11), and their extension direction all points to the preset working area.

2. The powder feeding cover according to claim 1, characterized in that, The inner wall of the through hole (11) is inclined outward along the direction of the wire feeding of the laser wire feeding assembly (2).

3. The powder feeding cover according to claim 1, characterized in that, A water-cooled flow channel is provided between each two adjacent powder feeding channels (112) inside the powder feeding cover (1).

4. A laser additive manufacturing wire and powder feeding device, characterized in that, The device includes the powder feeding cover (1) according to any one of claims 1-3, and also includes the laser wire feeding assembly (2). The laser wire feeding assembly (2) is configured with a wire feeding channel (21) and a plurality of laser generating devices (22). The plurality of laser generating devices (22) are arranged in a ring array with the wire feeding channel (21) as the center line. The plurality of powder feeding channels (112) are located outside the laser generating devices (22).

5. The laser additive manufacturing wire and powder feeding device according to claim 4, characterized in that, The number of laser generating devices (22) is odd, and no laser generating devices (22) are set at relatively opposite positions in the circumferential direction.

6. The laser additive manufacturing wire and powder feeding device according to claim 5, characterized in that, Each of the laser generating devices (22) includes a plurality of laser generators (221).

7. The laser additive manufacturing wire and powder feeding device according to claim 4, characterized in that, The number of laser generating devices (22) is the same as the number of powder feeding channels (112), and each powder feeding channel (112) is located between two adjacent laser generating devices (22).

8. The laser additive manufacturing wire and powder feeding device according to claim 4, characterized in that, Water-cooling channels are provided on the outside of the wire feeding channel (21) and inside each of the laser generating devices (22).

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