Heterogeneous powder feeding and recycling device and method for laser additive manufacturing

Abstract

The invention provides a device and a method for laser additive manufacturing heterogeneous powder feeding and recycling, and aims to solve the problems of residual powder pollution, powder waste, back blowing of powder in a powder feeding pipeline and the like in the gas feeding process of various heterogeneous powder. The device comprises a powder feeding pipe, a bottom plate, a disc seat, a rotating body, a disc, a cover plate and a servo motor, and efficient switching of various heterogeneous powder and cleaning and recycling of residual powder are achieved through a rotation driving and sliding block moving mechanism which is innovatively designed. The rotating body of the device is driven by a servo push-pull rod and is matched with a sliding block assembly with a radial through groove, residual powder is rapidly purged by inert gas, the powder is recycled into a collecting box through a recycling pipeline, the powder utilization rate is increased, and the deposition cost is reduced. Meanwhile, the rotating body is driven by the servo motor to rotate, switching of heterogeneous powder is achieved, the device can support feeding of three or more kinds of heterogeneous powder in an expanded mode, and the problem of pollution caused by back blowing of the powder can be effectively solved. The device is suitable for precise additive manufacturing and industrial application of various kinds of alloy powder, and has remarkable economic and environmental benefits.

Description

Technical Field

[0001] The present invention relates to the field of laser additive manufacturing, and in particular to a device and method for heterogeneous powder feeding and recycling in laser additive manufacturing. Background Art

[0002] Laser direct energy deposition (LDED) is an important branch of additive manufacturing. It has the functions of simultaneous forming and repairing and is widely used in aerospace, medical, mold manufacturing and other fields. Traditional laser directional energy deposition still faces some technical bottlenecks in the manufacture of complex heterogeneous structural materials. Specifically, spatial heterogeneous structural materials refer to the use of specific laser additive processes to utilize the distribution characteristics of different materials in the same structure to achieve spatial grading of material properties. Its material properties, organizational structure and chemical composition show spatial variations in different regions. This structural design allows the material to meet complex and multifunctional requirements while maintaining lightweight and synergistic improvement of strength and plasticity. However, since spatial heterogeneous materials require the alternating use of multiple metal powders (such as nickel-based high-temperature alloys, titanium alloys, high entropy alloys, iron-based alloys, etc.) during the deposition process and use special additive paths, they often face problems such as powder feeding path contamination and difficulty in recycling heterogeneous powders.

[0003] Specifically, in the LDED process, different metal powders are alternately fed into the laser head through a multi-channel powder feeding system. However, the residual powder in the powder feeding pipeline and the laser head will contaminate the subsequent powder, resulting in unstable performance of the deposited material and affecting the quality of the component. Therefore, how to effectively clean the residual powder in the pipeline and the laser head to prevent cross-contamination has become a key issue in the spatial heterogeneous structure LDED technology. At present, common solutions in the industry include starting the method of advance powder feeding, which cleans the residual powder in the pipeline by advance powder feeding before the laser deposition of the latter powder material. However, although this method can alleviate the problem of cross-contamination, a large amount of powder will be consumed in the process of advance powder feeding, especially some high-cost alloy powders, which will lead to a significant increase in production costs. This problem is particularly prominent for the use of high-value alloy powders, further limiting the promotion and application of this technology.

[0004] Most of the current heterogeneous powder feeding systems use different powder feeding barrels (or powder feeding pipes) connected to the laser head through three-way and four-way joints. Although this joint structure is simple, it cannot effectively prevent the back-blowing problem of powder due to the lack of a check valve function. The back-blowing phenomenon not only causes powder contamination, but may also cause damage to the equipment, thereby affecting production efficiency and quality. Therefore, the existing powder feeding device cannot completely avoid the problem of powder cross-contamination and waste. In addition, most of the existing heterogeneous powder feeding systems lack an effective powder recovery mechanism, resulting in a large amount of powder being wasted or unable to be effectively reused. The recovery and reuse of powders can not only reduce production costs, but also reduce environmental pollution, which is in line with the current trend of green manufacturing and sustainable development. However, most of the current LDED devices have failed to effectively realize the recycling of heterogeneous powders, especially when multiple powders are used alternately, the work of recovering and cleaning residual powder becomes particularly complicated. Summary of the invention

[0005] In order to solve the high cost problem caused by a large amount of early powder feeding or the use of complex pipeline cleaning technology in the LDED process using multiple powder materials, to prevent residual powder from contaminating subsequent powder materials, to reduce powder waste, and to achieve powder recovery and reuse, the present invention discloses a device and method for heterogeneous powder feeding and recovery in laser additive manufacturing.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] In the first aspect, the present invention proposes a device for heterogeneous powder feeding and recycling in laser additive manufacturing, comprising a base plate, a disc seat, a rotating body, a disc and a cover plate; a plurality of powder feeding pipe openings and air inlet pipe openings are arranged above the cover plate, the bottom of the cover plate is fixedly connected to the disc, and the disc and the cover plate are both provided with air delivery channels and powder feeding channels that are closely connected up and down, the air delivery channel is located at the center of the disc, the upper side is connected to the air inlet pipe opening, the upper side of the powder feeding channel is connected to the powder feeding pipe opening, and the lower part of the disc is a rotating body. The rotating body is connected to the rotating drive device, a through groove is opened in the rotating body along a radial direction, a perforated slider is arranged in the through groove, a hole is opened on the perforated slider, the perforated slider is connected to the linear drive device, the lower side of the rotating body is connected to the disc seat through an annular guide rail slider mechanism, the disc seat is fixedly connected to the bottom plate, a central hole and a powder recovery hole are opened on the disc seat and the bottom plate, a powder feeding pipe is connected below the central hole, and the other end of the powder feeding pipe is connected to the laser head.

[0008] As a further technical solution, the rotation drive device includes a servo motor, the output shaft of the servo motor is fixedly connected to the gear located below through holes of corresponding size and position on the cover plate, the gear is meshed with the circular arc rack, and the circular arc rack is fixedly connected to the rotating body.

[0009] As a further technical solution, the linear drive device includes a servo push-pull rod, the output power side of the servo push-pull rod is connected to the inner wall of the outer end face of the hole slider, and when the servo push-pull rod receives a signal, it can drive the hole slider to move back and forth radially in the rotating body.

[0010] As a further technical solution, the air inlet pipe opening is connected to an inert gas pipeline.

[0011] As a further technical solution, the multiple powder delivery pipe openings are connected to different powder delivery pipelines.

[0012] As a further technical solution, the multiple powder delivery pipe openings are located outside the air inlet pipe opening.

[0013] As a further technical solution, the number of the powder delivery channels and the powder delivery pipe openings is equal, and each powder delivery channel and each powder delivery pipe opening is independent of each other.

[0014] As a further technical solution, the central channel and the powder recovery channel are independent of each other; wherein the diameter of the central channel gradually decreases from top to bottom along the height direction of the disc seat; and the diameter of the powder recovery channel gradually decreases from top to bottom along the height direction of the disc seat.

[0015] As a further technical solution, the powder recovery channel is connected to a powder screening and collecting device.

[0016] In the second aspect, based on the above-mentioned device for heterogeneous powder feeding and recycling in laser additive manufacturing, the present invention also discloses a heterogeneous powder feeding and recycling method as follows:

[0017] The inert gas pipeline is connected to the air inlet pipe, and the gas cylinder connected to the inert gas pipeline is always open; the first powder is delivered to the first powder delivery pipe. At this time, the rotary drive device is not turned on, the rotating body is in the initial position, the linear drive device is not turned on, and the inner end face of the hole-opening slider is seamlessly attached to the rotating body, blocking the communication between the gas transmission channel and the central channel, and the upper side of the channel on the hole-opening slider is connected to the first powder delivery channel, and the lower side is connected to the central channel. The first powder is transported to the laser head through the first powder delivery pipe, the first powder delivery channel, the channel, the central channel and the powder delivery pipe. The coaxial powder is melted and deposited to form a first material cladding layer. When a layer of the first material is deposited, the linear drive device receives an electrical signal and turns on, pushing the hole-opening slider to move smoothly along the through slot to the outside of the rotating body. At this time, the inner end face of the hole-opening slider is connected to the The rotating body gradually separates to form a cavity, thereby connecting the gas delivery channel and the central channel. The inert gas enters the powder delivery pipe and the laser head through the above-mentioned channel, effectively blowing out the first powder remaining in the powder delivery pipe and the laser head. At the same time, with the further movement of the perforated slider, the position of the upper channel is translated, and the lower side of the channel is no longer connected with the central channel, but gradually connected with the first powder recovery channel. The first powder is recovered into the heterogeneous powder collection box through the first powder delivery pipe mouth, the first powder delivery channel, the channel, the first powder recovery channel and the subsequent connected pipelines, and then the powder delivery device is closed, and the first powder is collected. After the set residual powder cleaning time has passed, the linear drive device pulls the perforated slider along the through groove to move to the inside of the rotating body and seamlessly connects with it, the cavity disappears, and the central channel no longer transports inert gas.

[0018] The second powder begins to be deposited. The rotary drive device receives an electrical signal and generates power to drive the rotating body to rotate a set angle (±90°) relative to the disc and the disc seat through the output shaft, gear and arc rack. At this time, the hole on the open-hole slider is connected to the second powder feeding hole, and then the second powder is air-fed to the second powder feeding pipe port to achieve the deposition and recovery of the second powder. According to this step, the deposition and recovery of other powders are completed in turn.

[0019] The technical solution adopted by the present invention is as follows:

[0020] The present invention provides a device and method for heterogeneous powder feeding and recycling in laser additive manufacturing, aiming to solve the problems of residual powder pollution, powder waste and back-blowing of powder feeding pipelines during the gas delivery of various heterogeneous powders; the device realizes efficient switching of various heterogeneous powders, residual powder cleaning and recycling through innovatively designed rotary drive and slider moving mechanisms; the rotating body of the device is driven by a servo motor, and cooperates with a slider assembly with radial through grooves to realize rapid purge of residual powder by inert gas, and recover the powder to a collection box through a recovery pipeline, thereby improving powder utilization and reducing deposition costs. At the same time, the device can be expanded to support the feeding of three or more heterogeneous powders, and can effectively avoid the problem of powder back-blowing pollution. The device is suitable for precision additive manufacturing and industrial applications of various alloy powders (such as nickel-based high-temperature alloys, titanium alloys, high-entropy alloys, etc.), and has significant economic and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of a heterogeneous powder feeding and recovery device;

[0022] Figure 2 This is a schematic diagram of the disc seat of the heterogeneous powder feeding and recovery device;

[0023] Figure 3 It is a schematic diagram of the central rotating body of the heterogeneous powder feeding and recovery device;

[0024] Figure 4 This is a half-section diagram of the heterogeneous powder feeding and recovery device.

[0025] In the figure: 1. powder delivery pipe; 11. first powder recovery pipe; 12. second powder recovery pipe; 13. third powder recovery pipe; 2. bottom plate; 3. disc seat; 31. first powder recovery channel; 32. second powder recovery channel; 33. third powder recovery channel; 34. center channel; 4. rotating body; 41. perforated slider; 411. channel; 42. servo push-pull rod; 5. disc; 51. first powder delivery channel; 52. air delivery channel; 6. cover plate; 61. first powder delivery pipe opening; 62. second powder delivery pipe opening; 63. third powder delivery pipe opening; 64. air inlet pipe opening; 7. servo motor; 71. output shaft; 72. gear; 73. arc rack. DETAILED DESCRIPTION

[0026] In order to better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0027] Various aspects of the invention are described in this disclosure with reference to the accompanying drawings, in which many illustrative embodiments are shown. The embodiments of the present disclosure are not necessarily intended to include all aspects of the invention. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any laser additive manufacturing heterogeneous structure material device in many ways, because the concepts and embodiments disclosed in the present invention are not limited to any implementation. In addition, some aspects of the present disclosure can be used alone or in any appropriate combination with other aspects of the present disclosure.

[0028] This embodiment uses three kinds of powder materials (powder material A, powder material B, and powder material C) as examples to illustrate the present invention.

[0029] In the process of laser direct energy deposition (LDED) of spatial heterogeneous structure materials, when multiple powder delivery tubes are used to alternately gaseous heterogeneous powders (such as nickel-based high-temperature alloys, titanium alloys, high-entropy alloys, iron-based alloys, etc.) to the same laser head, on the one hand, the former powder material A remaining in the gas delivery pipeline and the laser head will pollute the subsequent gas-delivered powders B, C, etc., thereby affecting the purity of the spatial heterogeneous structure material; on the other hand, in view of the former problem, the early powder delivery is started before the laser directed energy deposition of the latter powder B, although the residual powder A can be brought out to reduce the powder contamination during deposition, but it will also cause a large amount of powder waste, especially when depositing alloy powders with high deposition costs, which will greatly increase the experimental expenses. In addition, the current heterogeneous powder delivery is often achieved by connecting different powder delivery tubes (powder delivery pipelines) to the laser head through three-way and four-way joints without check valve function, which cannot prevent the backflow of powder and also cause powder contamination. Therefore, the present invention first aims to design a heterogeneous powder feeding and recovery device, so as to realize the cleaning of residual powder in the air delivery pipeline and laser head and the recovery of heterogeneous powder. At the same time, by increasing the number of air channels of the device, three or more types of heterogeneous powder feeding can be realized. This part of the specification takes the realization of three types of heterogeneous powder feeding as an example.

[0030] Combination Figure 1 As shown, a heterogeneous powder feeding and recovery device is provided in this embodiment, including a powder feeding pipe 1, a base plate 2, a disc seat 3, a rotating body 4, a disc 5, a cover plate 6 and a servo motor 7; wherein the cover plate 6, the disc 5, the rotating body 4, the disc seat 3 and the base plate 2 are arranged in sequence from top to bottom; the cover plate 6 and the disc 5 are fixed together, the rotating body 4 can rotate on the disc seat 3, and the disc seat 3 is fixed on the base plate 2.

[0031] A first powder delivery pipe opening 61, a second powder delivery pipe opening 62, a third powder delivery pipe opening 63 and an air inlet pipe opening 64 are provided above the cover plate 6. The first powder delivery pipe opening 61, the second powder delivery pipe opening 62 and the third powder delivery pipe opening 63 are located in the outer circle of the air inlet pipe opening 64. The first powder delivery pipe opening 61, the second powder delivery pipe opening 62 and the third powder delivery pipe opening 63 are independent of each other. The first powder delivery pipe opening 61, the second powder delivery pipe opening 62 and the third powder delivery pipe opening 63 are all connected to the corresponding A, B, C heterogeneous powder gas delivery pipelines, and the air inlet pipe opening 64 is connected to an inert gas pipeline (not shown in the figure).

[0032] The cover plate 6 is fixedly connected to the disc 5 by screws at the bottom, and the disc 5 and the cover plate 6 are both provided with four vertical channels closely connected with each other up and down, and the four vertical channels include an air delivery channel 52, a first powder delivery channel 51, a second powder delivery channel and a third powder delivery channel (not shown in the figure), the air delivery channel 52 is located at the center of the disc 5, and the upper side of the air delivery channel 52 is connected to the air inlet pipe port 64, the upper side of the first powder delivery channel 51 is connected to the first powder delivery pipe port 61, the second powder delivery channel is connected to the second powder delivery pipe port 62, and the third powder delivery channel is connected to the third powder delivery pipe port 63.

[0033] Specifically, the first powder delivery channel 51 , the second powder delivery channel, the third powder delivery channel and the powder delivery pipe opening communicating therewith above are of the same shape and size, and the horizontal distance between the channel center and the gas delivery channel 52 is the same.

[0034] Furthermore, a servo motor 7 is installed on the cover plate 6, and the output shaft 71 of the servo motor 7 is fixedly connected to the gear 72 located below through holes of corresponding size and position on the cover plate 6, and the gear 72 is meshed with an arc rack 73, and the arc rack 73 is fixedly connected to the rotating body 4. The servo motor 7, the output shaft 71, the gear 72, the arc rack 73, etc. constitute a rotation driving device of the rotating body 4, which is used to drive the rotating body 4 to rotate.

[0035] Furthermore, the rotating body 4 and the disc 5 are connected via an annular guide rail slider mechanism (not shown in the figure). After receiving the signal, the servo motor 7 drives the rotating body 4 to rotate around the central axis of the disc 5 through the output shaft 71, gear 72 and arc rack 73, that is, rotates along the annular guide rail slider mechanism.

[0036] Furthermore, the rotating body 4 is provided with a through groove along a radial direction, and a perforated slider 41 is arranged in the through groove, and a channel 411 is opened on the perforated slider 41. At the same time, a linear drive device is fixedly installed on the side of the rotating body 4 near the perforated slider 41, and the linear drive device includes a servo push-pull rod 42. The output power side of the servo push-pull rod 42 is connected to the inner side of the outer end surface of the perforated slider 41. When the servo push-pull rod 42 receives a signal, it can drive the perforated slider 41 to move back and forth radially in the rotating body 4.

[0037] Furthermore, the lower side of the rotating body 4 is connected to the disc seat 3 through an annular guide rail slider mechanism (not shown in the figure), and the disc seat 3 is fixedly connected to the bottom plate 2 through screws.

[0038] Furthermore, four holes are also provided on the disc seat 3 and the bottom plate 2, and the positions of the four holes correspond to the positions of the gas delivery channel 52, the first powder delivery channel 51, the second powder delivery channel and the third powder delivery channel on the disc 5; the holes include the central channel 34, the first powder recovery channel 31, the second powder recovery channel 32, and the third powder recovery channel 33. The central channel 34, the first powder recovery channel 31, the second powder recovery channel 32, and the third powder recovery channel 33 are non-cylindrical channels. For specific channel shapes, see Figure 2 , Figure 3 ; The central channel 34 and the first powder recovery channel 31, the second powder recovery channel 32, and the third powder recovery channel 33 are independent of each other; wherein the diameter of the central channel 34 gradually decreases from top to bottom along the height direction of the disc seat; the diameters of the first powder recovery channel 31, the second powder recovery channel 32, and the third powder recovery channel 33 gradually decrease from top to bottom along the height direction of the disc seat. Specifically, two mutually perpendicular channels are arranged on the disc seat 3, two triangular blocking members are formed in one of the channels, and one triangular blocking member is formed in the other channel; the inner side surfaces of the three triangular blocking members enclose a central channel 34 whose diameter gradually decreases from top to bottom, and the outer side surfaces of the three triangular blocking members and the end of the channel enclose the first powder recovery channel 31, the second powder recovery channel 32, and the third powder recovery channel 33 whose diameter gradually decreases from top to bottom.

[0039] A powder feeding pipe 1 is connected below the central channel 34, and the other end of the powder feeding pipe 1 is connected to a laser head (not shown in the figure). The first powder recovery channel 31 is connected to a heterogeneous powder collection box (not shown in the figure) through a first powder recovery pipe 11; the second powder recovery channel 32 is connected to a heterogeneous powder collection box (not shown in the figure) through a second powder recovery pipe; and the third powder recovery channel 33 is connected to a heterogeneous powder collection box through a third powder recovery pipe.

[0040] The specific working process is as follows:

[0041] When performing additive manufacturing of spatial heterogeneous structure materials, first, the inert gas pipeline is connected to the air inlet port 64, and the gas cylinder connected to the inert gas pipeline is always open, and the powder pipeline connected to the first powder delivery port 61 starts to gas-feed powder A to the heterogeneous powder delivery and recovery device through the control of the powder delivery device. At this time, the servo motor 7 is not turned on, the rotating body 4 is in the initial position (0°), the servo push-pull rod 42 is not turned on (the rod is in the shortest extension state), and the inner end surface of the hole slider 41 is seamlessly attached to the rotating body 4. The gas delivery channel 52 is blocked from communicating with the central channel 34. At this time, the inert gas cannot be further transmitted through the gas delivery channel 52. The upper side of the channel 411 on the opening slider 41 is connected to the first powder delivery channel 51, and the lower side is connected to the central channel 34. Powder A is transported to the laser head through the first powder delivery pipe port 61, the first powder delivery channel 51, the channel 411, the central channel 34 and the powder delivery pipe 1. The coaxial powder is melted and deposited to form a cladding layer of material A. When a layer of material A is deposited, the servo pusher is turned on. The pull rod 42 receives an electrical signal to open, pushing the hole slider 41 to move smoothly along the groove toward the outside of the rotating body 4. At this time, the inner end surface of the hole slider 41 gradually separates from the rotating body 4 to form a cavity, thereby connecting the gas delivery channel 52 and the central channel 34. The inert gas enters the powder delivery pipe 1 and the laser head through the above-mentioned channel. Since the cavity formed by the inner side of the hole slider 41 and the rotating body 4 is small at the beginning, the inert gas flow rate is fast at this time, which can effectively blow out the residual gas in the powder delivery pipe 1 and the laser head. At the same time, with the further movement of the opening slider 41, the position of the upper channel 411 is translated, and the lower side of the channel 411 is no longer connected with the central channel 34, but gradually connected with the first powder recovery channel 31. Powder A is recovered into the heterogeneous powder collection box through the first powder feeding pipe port 61, the first powder feeding channel 51, the channel 411, the first powder recovery channel 31 and the first powder recovery pipe 11 for reuse, thereby improving the utilization rate of the powder.

[0042] Then the powder feeding device is closed, and the A powder is collected. After the set residual powder cleaning time has passed, the servo push-pull rod 42 pulls the perforated slider 41 along the groove to move toward the inner side of the rotating body 4 and seamlessly connects with it, the cavity disappears, and the central channel 34 no longer transports inert gas. Then, another material B begins to be deposited. The servo motor 7 receives the electrical signal and generates power to drive the rotating body 4 to rotate ±90° relative to the disc 5 and the disc seat 3 through the output shaft 71, the gear 72 and the arc rack 73. At this time, the upper side of the channel 411 on the perforated slider 41 is no longer connected to the first powder feeding channel 51, but is connected to the second / third powder feeding channel. Then, the powder pipeline connected to the second powder feeding pipe port 62 starts to gas-feed powder B to the heterogeneous powder feeding and recovery device through the control of the powder feeding device, and repeats the above operation to achieve the deposition and recovery of material B.

[0043] The device and method for heterogeneous powder feeding and recycling in laser additive manufacturing proposed in this embodiment are intended to solve the problems of residual powder pollution, powder waste and back-blowing of powder feeding pipelines during the gas delivery of various heterogeneous powders; the device realizes efficient switching of various heterogeneous powders, residual powder cleaning and recycling through innovatively designed rotary drive and slider moving mechanisms; the rotating body of the device is driven by a servo motor, and cooperates with a slider assembly with radial through grooves to realize rapid purge of residual powder by inert gas, and recover the powder to the collection box through the recovery pipeline, thereby improving powder utilization and reducing deposition costs. At the same time, the device can be expanded to support the feeding of three or more heterogeneous powders, and can effectively avoid the problem of powder back-blowing pollution. The device is suitable for precision additive manufacturing and industrial applications of various alloy powders (such as nickel-based high-temperature alloys, titanium alloys, high-entropy alloys, etc.), and has significant economic and environmental benefits.

[0044] Finally, it needs to be further explained that the present embodiment only illustrates the heterogeneous powder feeding and recovery device using three heterogeneous materials as an example. It can also be designed into four, five, etc. types according to actual needs. The number of powder feeding pipe openings and channels of the heterogeneous powder feeding and recovery device can be increased or decreased by replacing the base plate 2, the disc seat 3, the disc 5 and the cover plate 6 to make the device more flexible.

Claims

1. A device for heterogeneous powder feeding and recycling in laser additive manufacturing, characterized in that: The invention comprises a bottom plate, a disc seat, a rotating body, a disc and a cover plate; a plurality of powder delivery pipe openings and air inlet pipe openings are arranged above the cover plate, the cover plate is fixedly connected to the disc below, the disc and the cover plate are both provided with air delivery channels and powder delivery channels which are closely connected with each other up and down, the air delivery channel is located at the center of the disc, the upper side is communicated with the air inlet pipe opening, the upper side of the powder delivery channel is communicated with different powder delivery pipe openings, the lower part of the disc is a rotating body, the rotating body is connected to a rotating drive device, a through groove is opened in the rotating body along a radial direction, an open hole slider is arranged in the through groove, a channel is opened on the open hole slider, the open hole slider is connected to a linear drive device, the lower side of the rotating body is connected to the disc seat through an annular guide rail slider mechanism, the disc seat is fixedly connected to the bottom plate, a central channel and a powder recovery channel are opened on the disc seat and the bottom plate, a powder delivery pipe is connected below the central channel, and the other end of the powder delivery pipe is connected to a laser head.

2. The device for laser additive manufacturing heterogeneous powder feeding and recycling according to claim 1, characterized in that: The rotary drive device comprises a servo motor, the output shaft of the servo motor is fixedly connected to the gear located below through holes of corresponding size and position on the cover plate, the gear is meshed with the circular arc rack, and the circular arc rack is fixedly connected to the rotating body.

3. The device for laser additive manufacturing heterogeneous powder feeding and recycling according to claim 1, characterized in that: The linear drive device includes a servo push-pull rod, the power output side of the servo push-pull rod is connected to the inner wall of the outer end surface of the perforated slider, and when the servo push-pull rod receives a signal, it can drive the perforated slider to move back and forth radially in the rotating body.

4. The device for laser additive manufacturing heterogeneous powder feeding and recycling according to claim 1, characterized in that: The air inlet pipe opening is connected to an inert gas pipeline.

5. The device for laser additive manufacturing heterogeneous powder feeding and recycling according to claim 1, characterized in that: The multiple powder delivery pipe openings are connected to different powder delivery pipelines.

6. The device for laser additive manufacturing heterogeneous powder feeding and recycling according to claim 1, characterized in that: The multiple powder delivery pipe openings are located outside the air inlet pipe opening.

7. The device for laser additive manufacturing heterogeneous powder feeding and recycling as claimed in claim 1, characterized in that: The number of the powder delivery channels and the powder delivery pipe openings is equal, and each powder delivery channel and each powder delivery pipe opening is independent of each other.

8. The device for laser additive manufacturing heterogeneous powder feeding and recycling as claimed in claim 1, characterized in that: The central channel and the powder recovery channel are independent of each other; wherein the diameter of the central channel gradually decreases from top to bottom along the height direction of the disc seat; and the diameter of the powder recovery channel gradually decreases from top to bottom along the height direction of the disc seat.

9. The device for laser additive manufacturing heterogeneous powder feeding and recycling according to claim 1, characterized in that: The powder recovery channel is communicated with the powder screening and collecting device.

10. A method for heterogeneous powder feeding and recycling of a device for laser additive manufacturing heterogeneous powder feeding and recycling based on any one of claims 1 to 9, characterized in that: as follows: The inert gas pipeline is connected to the air inlet pipe, and the gas cylinder connected to the inert gas pipeline is always open; the first powder is delivered to the first powder delivery pipe. At this time, the rotary drive device is not turned on, the rotating body is in the initial position, the linear drive device is not turned on, and the inner end face of the hole-opening slider is seamlessly attached to the rotating body, blocking the communication between the gas transmission channel and the central channel, and the upper side of the channel on the hole-opening slider is connected to the first powder delivery channel, and the lower side is connected to the central channel. The first powder is transported to the laser head through the first powder delivery pipe, the first powder delivery channel, the channel, the central channel and the powder delivery pipe. The coaxial powder is melted and deposited to form a first material cladding layer. When a layer of the first material is deposited, the linear drive device receives an electrical signal and turns on, pushing the hole-opening slider to move smoothly along the through slot to the outside of the rotating body. At this time, the inner end face of the hole-opening slider is connected to the The rotating body gradually separates to form a cavity, thereby connecting the gas delivery channel and the central channel. The inert gas enters the powder delivery pipe and the laser head through the above-mentioned channel, effectively blowing out the first powder remaining in the powder delivery pipe and the laser head. At the same time, with the further movement of the perforated slider, the position of the upper channel is translated, and the lower side of the channel is no longer connected with the central channel, but gradually connected with the first powder recovery channel. The first powder is recovered into the heterogeneous powder collection box through the first powder delivery pipe mouth, the first powder delivery channel, the channel, the first powder recovery channel and the subsequent connected pipelines, and then the powder delivery device is closed, and the first powder is collected. After the set residual powder cleaning time has passed, the linear drive device pulls the perforated slider along the through groove to move to the inside of the rotating body and seamlessly connects with it, the cavity disappears, and the central channel no longer transports inert gas. The second powder begins to be deposited, and the rotary drive device receives an electrical signal and generates power to drive the rotating body to rotate a set angle relative to the disc and the disc seat through the output shaft, gear and arc rack. At this time, the hole on the open-hole slider is connected to the second powder feeding hole, and then the second powder is air-fed to the second powder feeding pipe port to achieve the deposition and recovery of the second powder; according to this step, the deposition and recovery of other powders are completed in turn.

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