Powder feeder convenient to recycle and suitable for various materials and working method of powder feeder

Abstract

The invention belongs to the technical field of laser cladding, and discloses a powder feeder convenient to recycle and suitable for various materials and a working method of the powder feeder, and the powder feeder comprises a gas cylinder, a plurality of powder feeding devices and a main powder feeding pipe; each powder feeding device comprises a powder barrel cover and a powder barrel, and a sleeve penetrates through the top of the powder barrel cover and extends into the powder barrel; a screw rod is arranged in the sleeve and is driven by a motor; a filter screen is arranged on the lower portion of the sleeve, a heating device is arranged in the screw rod, and the heating device is used for heating the conveyed powder; a powder feeding pipe is arranged at the position close to the top of the sleeve, and the powder feeding pipe of each powder feeding device is connected with a main powder feeding pipe through a three-way connector. One end of the main powder feeding pipe is connected with the gas cylinder, and the other end is a powder outlet; and the gas cylinder also feeds gas into the powder feeding device through the gas conveying pipe. The requirements for stably supplying powder and uniformly mixing powder are met through a mixed powder feeding mode with spiral conveying as a main part and gas negative pressure conveying as an auxiliary part.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser cladding, in particular to a powder feeder convenient for recycling and suitable for various materials and a working method thereof. BACKGROUND

[0002] With the iterative development of laser cladding technology, a single coating cannot meet the demand for multiple performances, and a functional gradient coating gradually becomes a hotspot in the field of laser cladding, which needs to use multiple metal powders alternately multiple times in preparation.

[0003] However, the powder feeder disclosed in the prior art cannot ensure the removal of residual powder on the powder pipeline when switching the powder, which may cause contamination of the powder feeding path, seriously affecting the forming efficiency and quality of the functional gradient coating. Although some patent technologies can remove the residual powder on the powder pipeline, the structure is relatively complex and has poor practicability. In addition, for powder coating cladding, the "agglomeration" phenomenon may be caused by factors such as a humid environment, which may cause defects such as pores and affect the cladding quality. SUMMARY

[0004] The present application aims to solve the defects in the prior art and provide a powder feeder convenient for recycling and suitable for various materials, which adopts a mixed powder feeding mode of spiral conveying as the main mode and gas negative pressure conveying as the auxiliary mode to meet the demand for stable powder supply and uniform mixed powder supply.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: In a first aspect, the present application provides a powder feeder convenient for recycling and suitable for various materials, which comprises a gas cylinder, a plurality of powder feeding devices and a total powder feeding pipe. Each powder feeding device comprises a powder bucket cover and a powder bucket, a sleeve extends from the top of the powder bucket cover to the inside of the powder bucket; a screw rod is arranged in the sleeve, and the screw rod is driven by a motor located at the top of the powder bucket cover; a filter screen is arranged at the lower part of the sleeve, and a heating device is arranged in the screw rod to heat the powder in conveying; a powder feeding pipe is arranged near the top of the sleeve, and the powder feeding pipe of each powder feeding device is connected to the total powder feeding pipe through a three-way joint; one end of the total powder feeding pipe is connected to the gas cylinder, and the other end is a powder outlet; the gas cylinder also sends gas into the inside of the powder feeding device through a gas feeding pipe. The powder feeder adopts an integrated compact structure design, can effectively avoid contamination of the powder feeding path through a gas-powder separation method, meets the demand for small installation space, is modularized and can be quickly assembled and disassembled, and realizes zero leakage of powder and high recovery rate.

[0006] As a further technical solution, the three-way connector includes an air inlet, a powder inlet, and a powder outlet; wherein a first variable diameter section and a second variable diameter section are provided inside the air inlet; the inner diameter of the first variable diameter section gradually decreases along the direction of airflow, and the inner diameter of the second variable diameter section gradually increases along the direction of airflow.

[0007] As a further technical solution, a first powder sensor and a solenoid valve are installed on the powder feeding pipe; the first powder sensor is used to monitor the powder flow rate in the powder feeding pipe; the solenoid valve is used to control the opening and closing of the powder feeding pipe. As a further technical solution, a second powder sensor is installed at the end of the main powder feeding pipe; the second powder sensor is used to monitor the powder flow rate in the main powder feeding pipe.

[0008] As a further technical solution, a base support is also included, with a gas cylinder placed at the center of the base support and multiple powder feeding devices arranged around the gas cylinder; the main powder feeding pipe is an annular pipe that connects to each tee joint.

[0009] As a further technical solution, the base support includes a base, on which multiple support rods are vertically arranged, forming a circle, with the top connected to a ring. A ring of support plates is arranged in sequence around the circumference of the ring. Each support plate is arranged along the radial direction of the ring, and the end of the support plate is connected to a powder feeding device. The gas cylinder is arranged inside the circle formed by the multiple support rods.

[0010] As a further technical solution, anti-slip patterns are provided on the spiral blades of the screw rod, and replaceable wear-resistant strips are provided at the edge of the threaded blades.

[0011] As a further technical solution, a switch valve is installed on the connecting pipeline between the gas cylinder and the main powder delivery pipe, and a switch valve is also installed on the connecting pipeline between the gas cylinder and the gas delivery pipe.

[0012] As a further technical solution, the motor, switching valve, and solenoid valve of each of the above-mentioned powder feeding devices are controlled by the control system to realize the automatic control of the entire system.

[0013] Secondly, based on the aforementioned powder feeder that is easy to recycle and suitable for various materials, the present invention also provides a working method, as follows: First, different powders are poured into different powder feeding devices; The gas cylinder supplies protective gas to the main powder feeding pipe and the gas supply pipe of the first powder feeding device. The motor starts the screw rod to rotate and feed the powder upward. Under the combined action of gravity and air pressure, the powder in the powder bucket of the first powder feeding device passes through the filter screen to filter out the "agglomerated" powder and ensure that the powder particle size is uniform. The powder passes through the spiral blades and the screw rod equipped with a heating device to ensure that the powder is dry. The electromagnetic valve of the first powder feeding device is opened, the gas flow rate at the three-way joint is fast, negative pressure is formed at the powder feeding pipe joint of the first powder feeding device, and the powder flow is further pushed to the total powder feeding pipe and into the laser head; the first powder sensor of the first powder feeding device and the second powder sensor at the end of the powder feeding pipe can accurately monitor the powder flow rate, and the motor is negatively fed back to ensure stable and uniform powder feeding; if powder blockage occurs, the blockage position can be accurately determined through the flow feedback of the first powder sensor and the second powder sensor; After the first kind of powder cladding is completed, the electromagnetic valve of the first powder feeding device is closed, the motor of the first powder feeding device is reversed to ensure that the powder on the spiral blade smoothly falls back to the bottom of the barrel, the protective gas in the powder feeding pipe still flows, and the second powder sensor still monitors the powder flow rate at the end of the powder feeding pipe and near the laser head; at the same time, the protective gas can also blow away the first kind of powder remaining on the substrate during the process of the laser head returning to the cladding starting point, thereby minimizing human intervention; when the powder flow rate at the first powder sensor is zero, it indicates that there is no residual first kind of powder in the powder feeding path; At this time, the motor of the second powder feeding device is opened, the spiral rod starts to rotate to stably feed the second kind of powder upward, and the whole feeding process is the same as that of the first kind of powder, which will not be described here. If the third kind of powder needs to be fed after the second kind of powder is fed, the same method is adopted to feed the third kind of powder; and the same method is adopted to feed the third kind of powder, so as to realize the function of the functionally graded coating without powder pollution.

[0014] The beneficial effects of the present application are as follows: The present application realizes the needs of stable powder supply and uniform mixed powder supply by designing the structure of the powder feeding device, cooperating with the gas cylinder and the total powder feeding pipe, adopting the mixed powder feeding mode of spiral feeding as the main mode and gas negative pressure feeding as the auxiliary mode, and can realize the powder feeding of multiple materials; the gas cylinder respectively feeds the protective gas (such as inert gas) to the total powder feeding pipe and the gas feeding pipe of the powder feeding device, the motor starts the spiral rod to rotate and feed the powder upward; under the dual action of gravity and gas pressure, the powder in the powder barrel of the powder feeding device passes through the filter screen to filter out the "agglomerated" powder, so as to ensure the uniformity of the powder particle size; the powder passes through the spiral blade and the screw rod provided with a heating device to ensure the dryness of the powder; the motor is reversed to ensure that the powder on the spiral blade smoothly falls back to the bottom of the barrel, the protective gas in the powder feeding pipe still flows, and the first powder sensor still monitors the powder flow rate at the end of the powder feeding pipe and near the laser head. At the same time, the protective gas can also blow away the powder remaining on the substrate during the process of the laser head returning to the cladding starting point, thereby minimizing human intervention. When the powder flow rate at the second powder sensor is zero, it indicates that there is no residual powder in the powder feeding path.

[0015] Due to the reduced pipe diameter at the joint, the gas flow is faster, forming a negative pressure at the joint of the powder feeding pipe of the powder feeding device, further pushing the powder flow into the laser head through the main powder feeding pipe; The second powder sensor of the powder feeding device and the first powder sensor at the end of the powder feeding pipe can accurately monitor the flow of the powder, and the motor is negatively feedback regulated to ensure stable and uniform powder delivery; if powder blockage occurs, the blockage position can be accurately determined through the flow feedback of the first powder sensor and the second powder sensor.

[0016] When the experiment is finished, the buckle of the two powder buckets is loosened, and the powder bucket can be disassembled, thereby realizing high recovery rate of the remaining powder. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a whole schematic view of the powder feeding device disclosed in the embodiment; Figure 2 It is a partial sectional view of the powder feeding device disclosed in the embodiment; Figure 3 It is a partial sectional view of the powder feeding port disclosed in the embodiment; Figure 4 It is a sectional view of the tee joint disclosed in the embodiment; Figure 5 It is a whole schematic view of the powder bucket disclosed in the embodiment; Figure 6 It is a whole schematic view of the base support disclosed in the embodiment; In the figure: 1, gas cylinder; 2, main powder feeding pipe; 3, powder feeding device; 4, base support; 5, tee joint; 6, first powder sensor; 31, motor; 32, powder feeding port; 33, powder bucket cover; 34, buckle; 35, powder bucket; 36, sleeve; 37, filter screen; 38, screw rod; 39, gas feeding pipe; 321, second powder sensor; 322, electromagnetic valve; 323, powder feeding pipe; 381, replaceable wear-resistant strip; 382, anti-slip pattern; 383, heating device; 351, sealing ring; 41, fixed clamp; 42, powder cover support; 43, support; 44, base; 45, fixed pin; 51, gas feeding port; 52, powder inlet; 53, powder outlet; 511, first reducing section; 512, second reducing section; DETAILED DESCRIPTION It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0018] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. For the convenience of description, if the terms "upper", "lower", "left", "right" appear in the present application, they only mean the same direction as the upper, lower, left and right directions of the drawings themselves, and do not limit the structure, but only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, so it cannot be understood as a limitation on the present application.

[0019] In the prior art, when multiple powder feeding barrels are used to alternately deliver different kinds of powder to the same laser head in the laser direct energy deposition (L-DED) functional gradient coating process, on the one hand, the residual powder material in the gas feeding pipeline and the laser head will contaminate the subsequently fed powder, thereby affecting the quality of the functional gradient coating; on the other hand, to solve the above problem, the pre-delivery of powder is started before the laser directed energy deposition of the latter kind of powder, which can bring out the residual powder of the former kind and reduce the powder contamination during deposition, but at the same time, it will also cause a large amount of powder waste, especially when the alloy powder with high deposition cost is used, it will greatly increase the test cost. Therefore, the present application discloses a powder feeder convenient for recycling and suitable for multiple materials and a working method thereof, so as to realize the cleaning and recycling of the residual powder in the gas feeding pipeline and the laser head. In addition, by adjusting the base bracket and adding the powder feeding device, three or more different kinds of powder feeding can be realized. The present embodiment takes two kinds of powder feeding as an example for description.

[0020] As shown in Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , the powder feeder convenient for recycling and suitable for multiple materials disclosed in the present embodiment mainly comprises a gas cylinder 1, multiple powder feeding devices 3 and a total powder feeding pipe 2. Further, each powder feeding device 3 comprises a powder tank cover 33 and a powder tank 35, which are connected by a plurality of buckles 34; a ring of sealing rings 351 is arranged on the top of the powder tank 35, and a sleeve 36 extends from the top of the powder tank cover 33 to the inside of the powder tank 35; a screw rod 38 is arranged in the sleeve 36, which is driven by a motor 31 located at the top of the powder tank cover; a filter screen 37 is arranged at the lower part of the sleeve 36, and the powder in the powder tank 35 is filtered through the filter screen 37 and then enters the sleeve 36, and then is conveyed upward by the screw rod 38 and is conveyed to the powder feeding pipe 323, which is provided with a powder feeding port 32; and a heating device 383 is arranged in the screw rod, which heats the powder being conveyed; a powder feeding pipe 323 is arranged near the top of the sleeve 36, which is connected to the total powder feeding pipe 2 through a three-way joint 5; at the same time, the gas cylinder 1 also sends gas into the inside of the powder feeding device 3 through a gas feeding pipe 39, and the purpose of sending gas is mainly to increase the air pressure in the inside of the powder feeding device 3 and prevent low pressure in the inside of the powder feeding device 3, which causes the powder to be unable to be conveyed.

[0021] Further, in order to prevent the powder from sliding down during upward conveying, anti-skid lines 382 are arranged on the spiral blades of the screw rod 38.

[0022] Further, in order to prevent the edge position of the threaded blade from being worn, replaceable wear-resistant strips 381 are arranged at the edge position of the threaded blade.

[0023] Further, in order to support and fix the gas cylinder 1 and the plurality of powder feeding devices 3, the embodiment further comprises a base support 4, in the center of which the gas cylinder 1 is arranged, and around which the plurality of powder feeding devices 3 are arranged; the plurality of powder feeding devices 3 are connected to the same total powder feeding pipe 2; one end of the total powder feeding pipe 2 is connected to the gas cylinder 1, and the other end is a powder outlet; the total powder feeding pipe 2 is an annular pipe, which communicates with each powder feeding device 3, and the powder in each powder feeding device 3 can enter the total powder feeding pipe 2 through the three-way joint 5, thereby realizing the conveying of the powder.

[0024] As a further technical solution, as shown in Figure 3 A second powder sensor 321 and an electromagnetic valve 322 are arranged on the powder feeding pipe 323; the second powder sensor 321 is used to monitor the powder flow in the powder feeding pipe 323; the motor is subjected to negative feedback adjustment to ensure stable and uniform conveying of the powder; and the electromagnetic valve 322 is used to control the opening and closing of the powder feeding pipe 323.

[0025] As a further technical solution, a first powder sensor 6 is installed at the end of the main powder feeding pipe 2. The first powder sensor 6 is used to monitor the powder flow rate in the main powder feeding pipe 2. If powder blockage occurs, the blockage location can be accurately determined through the flow feedback of the first powder sensor 6 and the second powder sensor 321. If the flow rate of the first powder sensor 6 is zero, it is possible that both the main powder feeding pipe 2 and the powder feeding pipe 323 are blocked, or only the main powder feeding pipe 2 is blocked. If the flow rate of both the first powder sensor 6 and the second powder sensor 321 is zero, it indicates that both the main powder feeding pipe 2 and the powder feeding pipe 323 are blocked. If the flow rate of the first powder sensor 6 is zero, but the second powder sensor 321 has a flow rate value, it indicates that the main powder feeding pipe 2 is blocked. If the flow rate of the second powder sensor 321 is zero, it indicates that the powder feeding pipe 323 is blocked.

[0026] As a further technical solution, such as Figure 6 As shown, the base support 4 includes a base 44, on which multiple support rods are vertically arranged, forming a circle. The top of the support rods is connected to a ring to form a support 43. A series of fixed clamps 41 are arranged around the circumference of the ring. Each fixed clamp 41 is connected to a powder cap support 42. The end of the support plate is connected to the powder feeding device 3. A gas cylinder 1 is arranged inside the circle formed by the multiple support rods. The ring consists of multiple segments, which are connected to each other by fixing pins 45 to facilitate the installation of the powder feeding device 3.

[0027] As a further technical solution, the tee connector 5 in this embodiment is as follows: Figure 4 As shown, it includes an air inlet 51, a powder inlet 52, and a powder outlet 53; wherein a first variable diameter section 511 and a second variable diameter section 512 are provided inside the air inlet 51; the inner diameter of the first variable diameter section gradually decreases along the direction of airflow, and the inner diameter of the second variable diameter section gradually increases along the direction of airflow; the main purpose of this design is to increase the gas flow rate at the joint, to form a negative pressure at the junction of the powder feeding pipe 323 of the first powder feeding device, and to further push the powder to flow into the main powder feeding pipe 2 and enter the laser head.

[0028] Furthermore, a switch valve is installed on the connecting pipeline between the gas cylinder 1 and the main powder delivery pipe 2, and a switch valve is also installed on the connecting pipeline between the gas cylinder 1 and the gas delivery pipe. As a further technical solution, the motor of each powder feeding device 3, as well as each switching valve and solenoid valve 322, are all controlled by the control system to realize the automatic control of the entire system.

[0029] The specific working methods are as follows: First, two powder buckets 35 are released by loosening the buckle 34, and the mixed two kinds of first powder and second powder are poured into the two different powder feeding devices 3 respectively, the first powder is poured into the first powder feeding device, and the second powder is poured into the second powder feeding device; and the first powder feeding device and the second powder feeding device are sealed by locking the buckle 34.

[0030] Further, the gas cylinder 1 respectively supplies protective gas (such as argon and other inert gases) to the total powder feeding pipe 2 and the gas feeding pipe 39 of the first powder feeding device, and the motor 31 starts the screw rod 38 to start rotating to upwardly feed the powder: under the dual action of gravity and gas pressure, the powder in the powder bucket of the first powder feeding device passes through the filter screen 37 to filter out the "agglomerated" powder, ensuring uniform particle size of the powder; the powder passes through the screw blade and passes through the screw rod provided with the heating device 383, ensuring that the powder is dry; The electromagnetic valve 322 of the first powder feeding device is opened, and the total powder feeding pipe 2 and the powder feeding pipe 323 are connected by the three-way joint 5, and since the pipe diameter is reduced at the joint, the gas flow rate is relatively fast, a negative pressure is formed at the joint of the powder feeding pipe 323 of the first powder feeding device, further pushing the powder to flow into the total powder feeding pipe 2 and enter the laser head; the second powder sensor 321 of the first powder feeding device and the first powder sensor 6 at the end of the powder feeding pipe can accurately monitor the flow rate of the powder, and the motor is negatively fed back to adjust, ensuring stable and uniform feeding of the powder. If the powder is blocked, the flow feedback of the first powder sensor 6 and the second powder sensor 321 can accurately determine the blocking position.

[0031] Before cladding the second powder, the electromagnetic valve 322 is closed, the motor 31 of the first powder feeding device is reversed to ensure that the powder on the screw blade smoothly falls back to the bottom of the bucket, the protective gas in the powder feeding pipe still flows, and the first powder sensor 6 still monitors the flow rate of the powder at the end of the powder feeding pipe and near the laser head. At the same time, the protective gas can also blow away the first powder remaining on the substrate during the process of the laser head returning to the cladding starting point, thereby minimizing human intervention. When the flow rate of the powder at the second powder sensor 321 is zero, it indicates that there is no residual first powder in the powder feeding path; At this time, the motor 31 of the second powder feeding device is started to start the screw rod 38 to rotate to stably feed the second powder upward, and the whole feeding process is the same as that of the first powder, and thus will not be described here; If the third powder needs to be fed after the second powder is fed, the same method is used to feed the third powder; and in this way, the functionally gradient coating without powder pollution is realized. When the experiment is finished, the buckle 34 of the two powder buckets 35 is loosened, and the powder buckets are disassembled, thereby realizing high recovery rate of the remaining powder.

[0032] The application provides a powder feeder convenient to recycle and suitable for various materials and a working method, which realizes the needs of stable powder supply and uniform mixed powder supply through a mixed powder feeding mode mainly based on spiral conveying and supplemented by gas negative pressure conveying. In addition, the powder feeder adopts an integrated compact structure design, can effectively avoid powder feeding path pollution through a gas-powder separation method, meets the needs of small installation space, is modularized and quickly assembled and disassembled, and realizes powder zero leakage and high recovery rate.

[0033] The above merely describes the preferred embodiments of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall fall within the protection scope of the present application.

Claims

1. A powder feeder suitable for a variety of materials that is easily recycled, characterized in that, The device comprises a gas cylinder, a plurality of powder feeding devices and a total powder feeding pipe. Each powder feeding device comprises a powder tank cover and a powder tank, a sleeve extends from the top of the powder tank cover to the inside of the powder tank, a screw rod is arranged in the sleeve and is driven by a motor arranged at the top of the powder tank cover, a filter screen is arranged at the lower part of the sleeve, and a heating device is arranged in the screw rod to heat the powder during transportation, a powder feeding pipe is arranged near the top of the sleeve, and the powder feeding pipe of each powder feeding device is connected to the total powder feeding pipe through a tee joint.

2. The powder feeder for a variety of materials, which is easy to recycle according to claim 1, wherein The tee joint comprises a gas inlet, a powder inlet and a powder outlet, wherein a first variable diameter section and a second variable diameter section are arranged in the gas inlet, the first variable diameter section gradually decreases in diameter along the direction of the gas flow, and the second variable diameter section gradually increases in diameter along the direction of the gas flow.

3. The powder feeder for a variety of materials, which is easy to recycle according to claim 1, wherein A first powder sensor and a solenoid valve are arranged on the powder feeding pipe, the first powder sensor is used to monitor the powder flow in the powder feeding pipe, and the solenoid valve is used to control the opening and closing of the powder feeding pipe.

4. The powder feeder for a variety of materials, which is easy to recycle according to claim 3, wherein A second powder sensor is arranged at the end of the total powder feeding pipe, and the second powder sensor is used to monitor the powder flow in the total powder feeding pipe.

5. The recyclable, multi-material compatible powder feeder of claim 1, wherein, The device further comprises a base support, a gas cylinder is arranged at the center of the base support, and a plurality of powder feeding devices are arranged around the gas cylinder, the total powder feeding pipe is an annular pipe, and the tee joints are connected to each other.

6. The multi-material, recyclable, powder feeder of claim 5, wherein, The base support comprises a base, a plurality of support rods are vertically arranged on the base, the support rods form a circle, a top ring is connected to the top of the support rods, a plurality of support plates are arranged in the circumferential direction of the top ring, each support plate is arranged in the radial direction of the top ring, the end of each support plate is connected to a powder feeding device, and the gas cylinder is arranged in the circle formed by the support rods.

7. The recyclable, multi-material compatible powder feeder of claim 1, wherein, Anti-skid patterns are arranged on the helical blades of the screw rod, and replaceable wear-resistant strips are arranged at the edges of the helical blades.

8. The multi-material, recyclable, powder feeder of claim 1, wherein, Switch valves are arranged on the connecting pipelines between the gas cylinder and the total powder feeding pipe and between the gas cylinder and the gas feeding pipe.

9. The multi-material, recyclable, powder feeder of claim 8, wherein, The motors, switch valves and solenoid valves of each powder feeding device are controlled by a control system to realize automatic control of the whole system.

10. The method of claim 4, wherein the powder feeder is adapted to be used with a plurality of materials. The specific implementation is as follows: Different powders are poured into different powder feeding devices. The gas cylinder supplies protective gas to the total powder feeding pipe and the gas feeding pipe of the first powder feeding device, the motor starts to rotate the screw rod to start feeding the powder upward, the gravity and the gas pressure ensure the uniformity of the powder particle size, and the powder passes through the helical blades and the screw rod with the heating device to ensure the dryness of the powder. The solenoid valve of the first powder feeding device is opened, the gas flow is fast at the tee joint, a negative pressure is formed at the joint of the powder feeding pipe of the first powder feeding device to further push the powder to the total powder feeding pipe and the laser head, and the first powder sensor of the first powder feeding device and the second powder sensor at the end of the powder feeding pipe can accurately monitor the powder flow to negatively feedback the motor to ensure the stable and uniform feeding of the powder. If the powder is blocked, the first powder sensor and the second powder sensor can accurately determine the blocking position through the flow feedback. After the first kind of powder cladding is completed, the first powder feeding device electromagnetic valve is closed, the first powder feeding device motor is reversed, the powder on the spiral blade is ensured to slide back to the bottom of the barrel, the protective gas in the powder feeding pipe still flows, and the second powder sensor still monitors the powder flow at the end of the powder feeding pipe and near the laser head; at the same time, the protective gas can also blow away the first kind of powder remaining on the substrate during the process of the laser head returning to the starting point of cladding; when the powder flow at the first powder sensor is zero, it indicates that there is no residual first kind of powder in the powder feeding path; At this time, the motor of the second powder feeding device starts to rotate the screw rod to stably convey the second kind of powder, and the whole conveying process is the same as that of the first kind of powder; if the third kind of powder needs to be conveyed after the second kind of powder is conveyed, the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third kind of powder; and the same method is adopted to convey the third

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