Powder feeding device for conductive terminal of copper bus

Abstract

The invention discloses a copper busbar conductive terminal powder feeding device, and relates to the technical field of copper busbar conductive terminal blue light cladding paraxial powder feeding method.The copper busbar conductive terminal powder feeding device comprises a gas tank, the top of the gas tank is connected with a connecting pipe in a nested mode, one end of the connecting pipe is connected with a powder feeding piece, and the top of the powder feeding piece is provided with a conveying pipe in a nested mode; the powder feeding device comprises a laser head, a connecting piece and an adjusting chuck are arranged on the connecting piece, a powder feeding piece is arranged on the connecting piece, a conveying piece matched with the powder feeding piece is arranged at the bottom of the conveying pipe, the conveying piece is movably installed on the adjusting piece, and the adjusting piece is arranged on one side of the laser head. The powder feeding pipe is fixed to one side of the laser head and keeps an included angle of 0-10 degrees with the axis of the laser head through combined matching between the connecting piece and the adjusting chuck; the powder feeding pipe is still kept in a vertical state when the laser head deflects by a large angle, meanwhile, inert gas in the powder feeding pipe is subjected to pressure relief through the gas relief hole in the tail end of the powder feeding pipe, and stable powder feeding in a molten pool is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of a blue-light cladding side-axis powder feeding method for a copper busbar conductive terminal, in particular to a powder feeding device for a copper busbar conductive terminal. Background Art

[0002] As an important component of electrical connection, copper busbar is responsible for conducting large currents. In order to improve the conductivity efficiency, a silver layer is usually plated on the surface of the copper busbar joint. After long-term operation, the silver plating layer on the joint surface will be detached and damaged, resulting in increased joint resistance and heat generation, threatening the safe and stable operation of electrical equipment. Laser cladding technology can achieve metallurgical bonding of different cladding materials with the substrate, and has the advantages of low dilution rate, dense organization, and small thermal deformation. However, as high-reflectivity materials, copper and silver have low absorption rates for infrared wavelength lasers, resulting in poor cladding quality.

[0003] The existing side-axis powder feeding technology is a powder feeding method that is independent of the laser beam during the laser cladding process. Side-axis powder feeding requires a gravity powder feeder. The use of a turntable powder feeder cannot evenly pass the powder through the side-axis powder feeding nozzle and stably feed the powder in the powder feeder into the molten pool, making it impossible for the coating and the substrate to form a good metallurgical bond. The turntable powder feeder is limited to the inability to stably feed powder through side-axis powder feeding and the inability to achieve large-angle cladding of the laser head in the narrow gap space on the inner surface of the copper busbar conductive terminal. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above problems or problems existing in the prior art, the present invention is proposed.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a copper busbar conductive terminal powder feeding device, which includes a gas tank, wherein a connecting pipe is nested on the top of the gas tank, one end of the connecting pipe is connected to a powder feeding piece, a conveying pipe is nested on the top of the powder feeding piece, and a conveying piece that cooperates with the powder feeding piece is arranged at the bottom of the conveying pipe, the conveying piece is movably mounted on an adjusting piece, and the adjusting piece is arranged on one side of the laser head.

[0007] As a preferred solution of the copper busbar conductive terminal powder feeding device of the present invention, the adjusting member includes an adjusting frame and an adjusting chuck arranged on one side of the laser head, and the adjusting frame is arranged at the upper end of the adjusting chuck.

[0008] As a preferred solution of the copper busbar conductive terminal powder feeding device of the present invention, the adjustment frame includes a connecting block arranged on one side of the laser head, a connecting rod is arranged on the outer side of the connecting block, and one end of the connecting rod is connected to the adjustment plate.

[0009] As a preferred solution of the powder feeding device for the copper busbar conductive terminal of the present invention, a limiting groove is provided on the top of the adjustment plate, and the limiting groove passes through the connecting block.

[0010] As a preferred solution of the powder feeding device for the copper busbar conductive terminal of the present invention, the adjustment frame further includes an adjustment slot opened on one side of the adjustment plate, and the adjustment slot is connected to the limit slot.

[0011] As a preferred solution of the powder feeding device for the copper busbar conductive terminal of the present invention, the conveying member includes a connecting chuck and a powder feeding pipe, the connecting chuck and the powder feeding pipe are threadedly connected, a nozzle is provided at the bottom end of the powder feeding pipe, and the powder feeding pipe passes through the adjustment plate and the adjustment chuck at the same time.

[0012] As a preferred solution of the powder feeding device for the copper busbar conductive terminal of the present invention, the adjustment plate is arranged in an arc shape, the limiting groove is opened through the arc surface of the adjustment plate, and the width of the limiting groove is adapted to the diameter of the powder feeding pipe.

[0013] As a preferred solution of the powder feeding device for the copper busbar conductive terminal of the present invention, the adjusting member also includes a movable sleeve ring arranged at the end of the conveying member, the movable sleeve ring is slidably connected to the powder feeding pipe, and a pressure relief hole is opened on the powder feeding pipe, the pressure relief holes are distributed longitudinally along the powder feeding pipe, and the pressure relief holes pass through the powder feeding pipe.

[0014] As a preferred solution of the powder feeding device for the copper busbar conductive terminal of the present invention, a limiting hole is provided on the outer wall of the powder feeding tube, a positioning hole is provided on the outer wall of the movable sleeve, and the positioning hole passes through the movable sleeve, a positioning rod is provided inside the positioning hole, and the positioning rod passes through the positioning hole and is adapted to the size of the limiting hole.

[0015] As a preferred solution of the powder feeding device for the copper busbar conductive terminal of the present invention, the powder feeding component includes a powder feeder connected to the connecting pipe, a powder feeding tray is symmetrically arranged on the top of the powder feeder, and a silo is arranged on the top of the powder feeding tray.

[0016] Beneficial effects of the present invention: The present invention fixes the powder feeding tube on one side of the laser head and maintains an angle of 0-10° with the axis of the laser head through the combination of the connecting piece and the adjusting chuck, so that the powder after pressure relief can evenly enter the molten pool, preventing the powder from accumulating in the powder feeding tube, making the powder flow smoother and the cladding surface quality better, so that the powder feeding tube remains in a vertical state when the laser head is deflected at a large angle, thereby achieving the effect of large-angle cladding of the laser head in the narrow gap space on the inner surface of the copper busbar conductive terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0018] Figure 1 This is a schematic diagram of the overall structure of the powder feeding device for the copper busbar conductive terminal.

[0019] Figure 2 This is a schematic diagram of the structure of the adjustment component of the powder feeding device for the copper busbar conductive terminal.

[0020] Figure 3 Front view of the adjustment assembly of the powder feeding device for the copper busbar conductive terminal.

[0021] Figure 4 This is a schematic diagram of the connector structure of the powder feeding device for the copper busbar conductive terminal.

[0022] Figure 5 Rear view of the moving collar of the powder feeding device for copper busbar conductive terminals.

[0023] Figure 6 The laser head of the powder feeding device for the copper busbar conductive terminal is tilted 30° to achieve the cladding surface effect. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0025] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0026] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0027] Example 1

[0028] Reference Figures 1 to 5 , which is the first embodiment of the present invention, and this embodiment provides a powder feeding device for a copper busbar conductive terminal, which includes a gas tank 100, and the gas tank 100 is filled with an inert gas, and the inert gas is nitrogen, helium, argon, etc., wherein a connecting pipe 101 is nested and connected to the top of the gas tank 100, and the inert gas is effectively transported to the powder feeding piece 200 through the setting of the connecting pipe 101, and one end of the connecting pipe 101 is connected to the powder feeding piece 200, and the setting of the powder feeding piece 200 provides sufficient powder supply for powder feeding inside the molten pool, and a conveying pipe 204 is nested on the top of the powder feeding piece 200, and a conveying piece 300 matched with the powder feeding piece 200 is arranged at the bottom of the conveying pipe 204, and the powder can be smoothly transported to the focus spot position of the laser head laser irradiating the workpiece surface through the setting of the conveying piece 300, which ensures that the laser head can be used for the powder feeding. The laser head achieves large-angle cladding effect in the narrow gap space on the inner surface of the copper busbar conductive terminal. The conveying member 300 is movably installed on the adjusting member 400, and the adjusting member 400 is arranged on one side of the laser head. The wavelength of the laser head output beam is 380-500nm, the maximum load-bearing power is 5000W, and the spot diameter is 2-4mm. Through the setting of the adjusting member 400, the conveying member 300 is fixed on one side of the laser head and maintains an angle of 0-10° with the axis of the laser head, so that the powder after pressure relief can evenly enter the molten pool, preventing the powder from accumulating in the conveying member 300, making the powder flow smoother and the cladding surface quality better. When the laser head is deflected at a large angle, the conveying member 300 still remains in a vertical state, achieving the effect of large-angle cladding of the laser head in the narrow gap space on the inner surface of the copper busbar conductive terminal.

[0029] Preferably, the powder feeding member 200 includes a powder feeder 201 connected to the connecting pipe 101, the powder particle size in the powder feeder 201 is 30-157 μm, the powder feeding amount is 1-100 g / min, and a powder feeding tray 202 is symmetrically arranged on the top of the powder feeder 201. A connecting plug is arranged on the powder feeding tray 202. Through the symmetrical arrangement of the powder feeding tray 202, when the powder is transported, the conveying member 300 is connected to a connecting plug on the powder feeding tray 202 to transport the powder. When the powder in one silo 203 is used up, the conveying member 300 can be connected to the connecting plug on another powder feeding tray 202. The connection ensures uninterrupted delivery of powder, and at the same time it is convenient for the staff to add powder to the empty silo 203, so as to replenish the subsequent powder delivery needs. The silo 203 is arranged on the top of the powder feeding tray 202. Through the setting of the silo 203, the powder inside the silo 203 continues to fall into the powder feeding tray 202 for replenishment due to the influence of gravity, thereby realizing the uninterrupted powder in the powder feeding tray 202. The cladding powder passes through the silo 203, the powder feeding tray 202, the powder feeder 201, the conveying pipe 204, the powder feeding pipe 302 and the nozzle 303 in turn to reach the focusing spot position of the laser irradiated workpiece surface.

[0030] Furthermore, the conveying member 300 includes a connecting chuck 301 and a powder delivery pipe 302. The connecting chuck 301 and the powder delivery pipe 302 are threadedly connected. The setting of the connecting chuck 301 can effectively connect the powder delivery pipe 302 to the powder feeder 201. The setting of the powder delivery pipe 302 can effectively connect the powder feeder 201 to the nozzle 303. The bottom end of the powder delivery pipe 302 is provided with a nozzle 303, and the powder delivery pipe 302 simultaneously passes through the adjustment plate 401c and the adjustment chuck 402. The nozzle 303 is provided at the bottom end of the powder delivery pipe 302. The inner hole diameter of the nozzle 303 is 0.8-1.6mm, and the end of the nozzle 303 is 8-20mm away from the spot position of the laser irradiated on the workpiece. Through the setting of the nozzle 303, the distance for the powder to reach the surface of the workpiece irradiated by the laser head is shortened, and the powder feeding range of the powder is increased, which can ensure that the delivered powder can be smoothly transported to the focus spot position of the surface of the workpiece irradiated by the laser head, ensuring the large-angle cladding effect of the laser head in the narrow gap space on the inner surface of the copper busbar conductive terminal.

[0031] When in use, firstly, silver powder is put into the powder feeding plate 202, and is delivered to the nozzle 303 at the end of the powder feeding pipe 302 under the conveyance of the inert gas in the gas tank 100. Secondly, the powder feeding pipe 302 is limited by the adjusting member 400, and the powder feeding pipe 302 is fixed to one side of the laser head. The powder feeding pipe 302 and the nozzle 303 at the bottom of the powder feeding pipe 302 are driven to rotate by the rotation of the adjusting member 400, ensuring that the powder feeding pipe 302 maintains an angle of 0-10° with the axis of the laser head, so that the laser head can be largely When the angle is deflected, the powder feeding tube 302 remains in a vertical state. Then, the position of the movable ring 403 in the adjusting member 400 on the powder feeding tube 302 is adjusted so that two air leakage holes 203a are exposed on the powder feeding tube 3021 to relieve the pressure of the inert gas in the powder feeding tube 302 and reduce the pressure of the gas entering the nozzle 303. This can adjust the flow rate of the powder at the end of the nozzle 303 and ensure that the powder can be stably transported to the focal irradiation position of the laser head, thereby achieving the effect of stable powder feeding in the molten pool.

[0032] When the powder is transported, the conveying member 300 is connected to a connecting plug on the powder feeding tray 202 to transport the powder. When the powder in one silo 203 is used up, the conveying member 300 can be connected to a connecting plug on another powder feeding tray 202 to ensure uninterrupted transportation of the powder. At the same time, it is convenient for the staff to add powder to the empty silo 203, thereby replenishing the subsequent powder transportation needs.

[0033] In summary, the powder feeding tube is fixed on one side of the laser head and maintains an angle of 0-10° with the axis of the laser head, so that the powder after pressure relief can evenly enter the molten pool, preventing the powder from accumulating in the powder feeding tube, making the powder flow smoother and the cladding surface quality better. When the laser head is deflected at a large angle, the powder feeding tube remains vertical, achieving the effect of large-angle cladding of the laser head in the narrow gap space on the inner surface of the copper busbar conductive terminal.

[0034] Example 2

[0035] Reference Figure 2 to Figure 5 , which is the second embodiment of the present invention, is based on the previous embodiment, and is different from the previous embodiment in that: the adjusting member 400 includes an adjusting frame 401 and an adjusting chuck 402 arranged on one side of the laser head, and the adjusting frame 401 is arranged at the upper end of the adjusting chuck 402. Through the cooperation between the adjusting frame 401 and the adjusting chuck 402, the powder delivery pipe 302 can be effectively clamped and limited to ensure that the powder delivery pipe 302 maintains an angle of 0-10° with the axis of the laser head, so that the powder delivery pipe 302 remains in a vertical state when the laser head is deflected at a large angle.

[0036] It is worth noting that the adjustment frame 401 includes a connecting block 401a arranged on one side of the laser head, a connecting rod 401b is arranged on the outer side of the connecting block 401a, and an adjustment plate 401c is connected to one end of the connecting rod 401b. A limiting groove 401d is arranged on the top of the adjustment plate 401c, and the limiting groove 401d passes through the connecting block 401a. The adjustment plate 401c is arranged in an arc shape, and the limiting groove 401d passes through the arc surface of the adjustment plate 401c. The width of the limiting groove 401d is the same as that of the powder feeding The diameter of the tube 302 is adapted, and the limiting groove 401d is opened to facilitate the insertion of the powder delivery tube 302, thereby limiting the powder delivery tube 302, so that the nozzle 303 at the bottom of the powder delivery tube 302 can maintain an angle of 0-10° with the axis of the laser head when conveying powder, so that the powder delivery tube 302 can still remain in a vertical state when the laser head is deflected at a large angle, thereby achieving the effect of large-angle cladding of the laser head in the narrow gap space on the inner surface of the copper busbar conductive terminal.

[0037] Preferably, the adjustment frame 401 further includes an adjustment slot 401e provided on one side of the adjustment plate 401c, and the adjustment slot 401e is connected to the limit slot 401d. The opening of the adjustment slot 401e facilitates the staff to operate the powder delivery pipe 302 to pass through the adjustment frame 401, thereby saving operation time.

[0038] Furthermore, the adjusting member 400 also includes a movable ring 403 arranged at the end of the conveying member 300, and the movable ring 403 is slidably connected to the powder feeding pipe 302. By adjusting the up and down position of the movable ring 403, the number of circular holes of the air leakage hole 203a exposed to the air can be effectively controlled, so that the flow rate of the powder at the end of the nozzle 303 can be adjusted according to actual usage. The powder feeding pipe 302 is provided with pressure relief holes 403a, and the pressure relief holes 403a are distributed longitudinally along the powder feeding pipe 302, and the pressure relief holes 403a penetrate the powder feeding pipe 302. The pressure relief holes 403a are 4-6 circular holes with a diameter of 0.2-0.5mm, which are used to release the inert gas in the powder feeding pipe 302, reduce the pressure of the gas entering the nozzle 303, and ensure stable powder feeding in the molten pool.

[0039] Furthermore, a limiting hole 403b is provided on the outer wall of the powder delivery tube 302, a positioning hole 403c is provided on the outer wall of the movable ring 403, and the positioning hole 403c passes through the movable ring 403, and a positioning rod 403d is arranged inside the positioning hole 403c, the positioning rod 403d passes through the positioning hole 403c, and is adapted to the size of the limiting hole 403b, and the positioning rod 403d always passes through the inner side of the positioning hole 403c, wherein, when the staff adjusts the movable ring 403, the positioning rod 403d passes through the positioning hole 403c and the limiting hole 403b at the same time, so as to fix the movable ring 403 on the powder delivery tube 302; when the staff needs to move and adjust the movable ring 403, the positioning rod 403d only passes through the positioning hole 403c, so as to facilitate the movable ring 403 to better adjust the upper and lower positions on the powder delivery tube 302.

[0040] When in use, first fix the adjusting frame 401 to one side of the connecting block 401a through the connecting rod 401b, and then pass the powder feeding tube 302 through the limiting groove 401d and the adjusting chuck 402 to achieve the limiting fixation of the powder feeding tube 302 to prevent the powder feeding tube 302 from shaking during the conveying process, thereby causing the bottom nozzle 303 to move. Then adjust the position of the movable ring 403 on the powder feeding tube 302 so that two pressure relief holes 403a are exposed on the powder feeding tube 302. By adjusting the number of pressure relief holes 403a exposed on the powder feeding tube 302, the internal pressure relief pressure of the powder feeding tube 302 is adjusted, thereby adjusting the pressure relief speed of the inert gas in the powder feeding tube 302, realizing the adjustment of the powder flow rate at the end of the nozzle 303, and ensuring the effect of stable powder feeding in the molten pool.

[0041] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, and parameter values ​​such as temperature, pressure, etc., installation arrangements, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure of performing the function described herein, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, improvements, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to numerous modifications still falling within the scope of the appended claims.

[0042] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0043] It should be understood that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but for those of ordinary skill having the benefit of this disclosure, without undue experimentation, the development effort will be a routine task of design, fabrication, and production.

[0044] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A powder feeding device for a copper busbar conductive terminal, characterized in that: include, A gas tank (100), wherein a connecting pipe (101) is nested and connected at the top of the gas tank (100), one end of the connecting pipe (101) is connected to a powder feeding piece (200), a conveying pipe (204) is nested at the top of the powder feeding piece (200), a conveying piece (300) matching with the powder feeding piece (200) is arranged at the bottom of the conveying pipe (204), the conveying piece (300) is movably mounted on an adjusting piece (400), and the adjusting piece (400) is arranged on one side of a laser head.

2. The copper busbar conductive terminal powder feeding device according to claim 1, characterized in that: The adjusting member (400) comprises an adjusting frame (401) and an adjusting chuck (402) arranged on one side of the laser head, wherein the adjusting frame (401) is arranged at the upper end of the adjusting chuck (402).

3. The copper busbar conductive terminal powder feeding device according to claim 2, characterized in that: The adjustment frame (401) comprises a connection block (401a) arranged on one side of the laser head, a connection rod (401b) is arranged on the outside of the connection block (401a), and one end of the connection rod (401b) is connected to an adjustment plate (401c).

4. The copper busbar conductive terminal powder feeding device according to claim 3, characterized in that: A limiting groove (401d) is provided on the top of the adjustment plate (401c), and the limiting groove (401d) passes through the connection block (401a).

5. The copper busbar conductive terminal powder feeding device according to claim 4, characterized in that: The adjustment frame (401) further comprises an adjustment slot (401e) provided on one side of the adjustment plate (401c), and the adjustment slot (401e) is connected to the limiting slot (401d).

6. The copper busbar conductive terminal powder feeding device according to claim 5, characterized in that: The conveying member (300) comprises a connecting chuck (301) and a powder delivery pipe (302), wherein the connecting chuck (301) and the powder delivery pipe (302) are threadedly connected, a nozzle (303) is provided at the bottom end of the powder delivery pipe (302), and the powder delivery pipe (302) simultaneously passes through the adjustment plate (401c) and the adjustment chuck (402).

7. The copper busbar conductive terminal powder feeding device according to any one of claims 5 or 6, characterized in that: The adjustment plate (401c) is arranged in an arc shape, and the limiting groove (401d) is opened through the arc surface of the adjustment plate (401c), and the width of the limiting groove (401d) is adapted to the diameter of the powder delivery pipe (302).

8. The copper busbar conductive terminal powder feeding device according to claim 2, characterized in that: The adjusting member (400) further comprises a movable sleeve (403) arranged at the end of the conveying member (300), wherein the movable sleeve (403) is slidably connected to the powder delivery pipe (302), and a pressure relief hole (403a) is provided on the powder delivery pipe (302), wherein the pressure relief hole (403a) is distributed longitudinally along the powder delivery pipe (302), and the pressure relief hole (403a) passes through the powder delivery pipe (302).

9. The copper busbar conductive terminal powder feeding device according to claim 8, characterized in that: A limiting hole (403b) is provided on the outer wall of the powder delivery pipe (302), a positioning hole (403c) is provided on the outer wall of the movable ring (403), and the positioning hole (403c) passes through the movable ring (403), and a positioning rod (403d) is provided inside the positioning hole (403c), and the positioning rod (403d) passes through the positioning hole (403c) and is adapted to the size of the limiting hole (403b).

10. The copper busbar conductive terminal powder feeding device according to claim 1, characterized in that: The powder feeding component (200) comprises a powder feeder (201) connected to the connecting pipe (101), a powder feeding tray (202) is symmetrically arranged on the top of the powder feeder (201), and a silo (203) is arranged on the top of the powder feeding tray (202).

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