CN211665179U

CN211665179U - Paraxial powder feeding device

Info

Publication number: CN211665179U
Application number: CN201922314659.5U
Authority: CN
Inventors: 王豫跃; 李长久; 杨冠军
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2019-12-20
Filing date: 2019-12-20
Publication date: 2020-10-13
Anticipated expiration: 2029-12-20

Abstract

The utility model discloses a paraxial powder feeding device, which belongs to the technical field of laser additive manufacturing, wherein the included angle between the laser beam direction and the powder feeding direction of the powder feeding cavity is 5-45 degrees, the laser beam direction in the included angle range is matched with the powder feeding direction of the powder feeding cavity to ensure that most of the energy of the laser beam is used for heating, melting and accelerating the powder particles in flight, only a very small amount of light beam energy can heat a basal body, thereby avoiding the basal body from being overheated to greatly reduce the dilution rate, reducing the deformation and dilution rate of the basal body, greatly improving the powder utilization rate and the processing efficiency, ensuring that the effective components of a coating are not influenced by the basal body material to improve the corrosion-resistant and wear-resistant effects of the coating, and the laser beam direction in the included angle range is matched with the powder feeding direction of the powder feeding cavity to realize laser ultra-high-speed cladding processing and form a coating with strong metallurgical bonding on the surface of the basal, the bonding strength between the coating and the base material and the laser cladding efficiency are improved.

Description

Paraxial powder feeding device

Technical Field

The utility model relates to a laser vibration material disk, laser cladding and laser hot spraying technical field especially relate to a paraxial powder feeding device.

Background

Most of core key parts of modern high-end equipment are moving parts, and frequent damage and even failure of the core key parts are caused by abrasion, corrosion, fatigue and the like, so that the long-term reliable operation of equipment is threatened, and a large amount of expensive core key parts are scrapped, thereby causing huge economic loss, resource waste and energy waste.

On one hand, the traditional wear-resistant corrosion-resistant nickel-based alloy coating preparation equipment has the characteristics of large size, high hardness, high melting point and the like of the used nickel-based powder, and the problem of poor powder particle melting exists in the coating preparation process, so that the prepared coating has the defects of easiness in cracking, low density and the like, and the production requirement cannot be met.

On the other hand, the traditional coating processing equipment has the problems of low heat input control accuracy, low processing efficiency, serious pollution and the like, so that the matrix is heated too much and deforms seriously, and the prepared nickel-based alloy coating has poor corrosion resistance and abrasion resistance due to serious cracking. Therefore, a new process for preparing a nickel-based material coating is needed to meet the actual production requirement, and the problem that the nickel-based alloy coating has a high cracking tendency in the preparation process to cause the deterioration of wear resistance and corrosion resistance is solved.

However, the laser spraying equipment commonly used in the market at present is actually light external powder of powder-coated laser regardless of coaxial powder feeding or paraxial powder feeding. The problems of short action time of laser and powder caused by external powder feeding by light, low processing precision of a powder feeding nozzle, low utilization rate of powder and the like

Disclosure of Invention

The utility model provides a paraxial powder feeding device, through optimizing the contained angle between powder feeding cavity and the light beam chamber and realizing that the powder assembles at the facula central point, make the energy majority of laser beam be used for heating melting and the powder particle in the flight with higher speed, and can realize that hypervelocity laser cladding forms metallurgical bonding coating, avoided the base member by the superheating and reduced the dilution rate by a wide margin, the base member deflection and dilution rate have been reduced, can increase substantially powder utilization ratio and machining efficiency, thereby guarantee that the effective component of coating does not receive base material's influence and improve the anticorrosive wear-resistant effect of coating.

The utility model provides a specific technical scheme as follows:

the utility model provides a pair of paraxial powder feeding device includes the device body and fixes connecting device on the device body, wherein, connecting device be used for with paraxial powder feeding device is fixed mutually with other parts, be provided with on the device body and send the powder chamber, send the contained angle between powder chamber and the vertical face to be 5 ~ 45.

The device comprises a device body, a powder feeding cavity, a powder discharging cavity and a powder conveying device, wherein the device body is provided with a laser beam channel in an inverted conical structure, the powder feeding cavity is arranged on one side of the laser beam channel, and an included angle between the powder feeding cavity and the laser beam channel is 5-45 degrees; the powder feeding cavity is of a cylindrical structure, and the convergence point of the section center line of the powder feeding cavity and the section center line of the laser beam channel is in the same plane.

Optionally, the cross section of the laser beam channel is of a semicircular structure or a semi-square structure, and the powder feeding cavity comprises a plurality of cylindrical powder feeding pipes arranged side by side.

Optionally, the total number of the cylindrical powder feeding pipes is an odd number, the cylindrical powder feeding pipe located in the middle is a central powder feeding pipe, the cylindrical powder feeding pipes located at two sides of the central powder feeding pipe are side powder feeding pipes, and a distance between an outlet of each side powder feeding pipe and an outlet of each central powder feeding pipe is smaller than a distance between an inlet of each side powder feeding pipe and an inlet of each central powder feeding pipe.

Optionally, an included angle between the center line of the side powder feeding pipe and the center line of the central powder feeding pipe is 5-30 °.

Optionally, the cylindrical powder feeding pipe is composed of 4 sections of cylindrical pipes with different diameters, and the diameters of the cylindrical pipes are sequentially decreased from top to bottom.

Optionally, the device body includes a device central body and a side cover fixed on one side of the device central body, wherein the powder feeding cavities are distributed along a splicing surface between the side cover and the device central body.

Optionally, the powder pipe is sent to the cylindricality is concatenation components of a whole that can function independently structure, the powder pipe is sent to the cylindricality is including the left body and the right body of mutual concatenation cooperation, wherein, left side body is located the device central body is relative the terminal surface of side cap, right side body is located the side cap is relative the terminal surface of device central body.

Optionally, a cooling cavity is arranged on the outer side of the powder feeding cavity, the connecting device is arranged at the upper end of the device body, a connecting flange is arranged on the connecting device and used for being fixed with other components, and the laser beam channel penetrates through the device body and the connecting device.

Optionally, a cooling cavity cover is fixed to the side of the device body, the cooling cavity cover and the device body are matched with each other to form the cooling cavity, a cooling pipe mounting hole is formed in the cooling cavity cover, the connecting device comprises a base fixed to the device body, a connecting flange fixed to the base, and end covers fixed to the device body and the cooling cavity cover respectively, a powder feeding head mounting hole is formed in the end cover, and the powder feeding head mounting hole is communicated with the cylindrical powder feeding pipe.

The utility model has the advantages as follows:

the embodiment of the utility model provides a paraxial powder feeding device comprises a device body and a connecting device fixed on the device body, wherein, the device body is provided with a laser beam channel with an inverted cone structure, a powder feeding cavity is arranged at one side of the laser beam channel, an included angle between the powder feeding cavity and the laser beam channel is 5-45 degrees, namely, the included angle between the laser beam direction and the powder feeding direction of the powder feeding cavity is 5-45 degrees, the laser beam direction in the included angle range is matched with the powder feeding direction of the powder feeding cavity to ensure that most of the energy of the laser beam is used for heating, melting and accelerating the powder particles in flight, only a very small amount of light beam energy can heat the basal body, the basal body is prevented from being overheated to greatly reduce the dilution rate, the deformation and dilution rate of the basal body are reduced, the powder utilization rate and the processing efficiency are greatly improved, the effective components of the coating are not influenced by the basal body material, thereby improving the corrosion-resistant and wear-resistant effects, and the laser beam direction in the included angle range and the powder feeding direction of the powder feeding cavity are matched with each other, so that ultrahigh-speed laser cladding processing can be realized, a coating with strong metallurgical bonding can be formed on the surface of the base material, and the bonding strength between the coating and the base material and the laser cladding efficiency are improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic isometric view of a paraxial powder feeder according to an embodiment of the present invention;

fig. 2 is another isometric schematic view of a paraxial powder feeder according to an embodiment of the present invention;

fig. 3 is a schematic front view of a paraxial powder feeder according to an embodiment of the present invention;

fig. 4 is a schematic bottom view of a paraxial powder feeder according to an embodiment of the present invention;

fig. 5 is a front view of a paraxial powder feeder according to an embodiment of the present invention;

fig. 6 is a schematic top view of a paraxial powder feeder according to an embodiment of the present invention;

fig. 7 is a schematic sectional view of the direction a-a in fig. 6 according to an embodiment of the present invention;

fig. 8 is a schematic sectional view of the structure from B-B in fig. 6 according to an embodiment of the present invention;

fig. 9 is a schematic front view of a device body according to an embodiment of the present invention;

fig. 10 is a schematic top view of a device body according to an embodiment of the present invention;

fig. 11 is a schematic cross-sectional view of the C-C direction in fig. 9 according to an embodiment of the present invention;

fig. 12 is a schematic sectional view of the structure shown in fig. 10 from D-D direction according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

A paraxial powder feeder according to an embodiment of the present invention will be described in detail with reference to fig. 1 to 12.

Referring to fig. 1, fig. 2 and fig. 3, the embodiment of the present invention provides a paraxial powder feeding device, including device body 1 and connecting device 2 fixed on device body 1, wherein, connecting device 2 is used for fixing the utility model discloses a paraxial powder feeding device is fixed mutually with other parts, the example, the utility model discloses a paraxial powder feeding device's device body 1 passes through connecting device 2 to be fixed on laser cladding device or laser spray melting equipment.

Referring to fig. 1, 6 and 7, a laser beam channel 3 with an inverted cone structure is arranged on a device body 1, a powder feeding cavity 4 is arranged on one side of the laser beam channel 3, and an included angle between the powder feeding cavity 4 and the laser beam channel 3 is 5-45 °. Specifically, the included angle between the powder feeding cavity 4 and the laser beam channel 3 may be an included angle a shown in fig. 7, where the included angle a is an included angle between a center line of the powder feeding cavity 4 and a right end face of the laser beam channel 3, and the included angle a may also be an included angle between a center line of the powder feeding cavity 4 and a vertical plane where the laser beam channel 3 is located. A large number of experiments and practices show that the paraxial powder feeding device can be ensured to be used for realizing ultrahigh-speed laser cladding only when the included angle between the powder feeding cavity 4 and the laser beam channel 3 is 5-45 degrees.

Referring to fig. 7, 9, 11 and 12, the powder feeding cavity 4 of the embodiment of the present invention is a cylindrical structure, and the convergence point of the cross-sectional center line of the powder feeding cavity 4 and the cross-sectional center line of the laser beam channel 3 is in the same plane. Referring to fig. 1, 4, 6, 7, 9, 11 and 12, the powder feeding chamber 4 is composed of a plurality of cylindrical powder feeding pipes 401 arranged side by side, wherein each cylindrical powder feeding pipe 401 is arranged obliquely in the vertical direction, the laser beam passage is arranged vertically in the vertical direction, the central axis of each cylindrical powder feeding pipe 401 intersects with the central axis of the laser beam passage 3, and the intersection points between the central axes of all the cylindrical powder feeding pipes and the central axis of the laser beam passage are in the same horizontal plane, that is, the intersection points between the central axes of all the cylindrical powder feeding pipes and the central axis of the laser beam passage form a cake-shaped structure in the same horizontal plane, so that a cake coating can be formed at the convergence point of the light beams in the laser beam passage, and the cake formed at the outlet of the powder feeding chamber has a certain diameter and can be converged with the laser beams above the convergence point of the laser beams, the laser beam is contacted with the powder cake before reaching the surface of the matrix, so that most of the energy of the laser beam is used for heating, melting and accelerating the powder particles in flight, only a very small amount of the energy of the laser beam can heat the matrix, the matrix is prevented from being overheated to greatly reduce the dilution rate, the deformation and the dilution rate of the matrix are reduced, the powder utilization rate and the processing efficiency can be greatly improved, and the effective components of the coating are not influenced by the matrix material, so that the corrosion-resistant and wear-resistant effects of the coating are improved.

For example, referring to fig. 7, 8, 9 and 12, the cross section of the device body 1 is a half-fan-shaped structure, wherein the cross-sectional centerline of the powder feeding cavity 4 (i.e. the central axis of each cylindrical powder feeding tube) and the cross-sectional centerline of the laser beam channel 3 (i.e. the intersection line between the central axis surface in the width direction and the central axis surface in the width direction of the laser beam channel) are respectively overlapped with different radius lines of the circle where the fan-shaped structure is located, i.e. the powder feeding cavity 4 and the laser beam channel 3 are both arranged along the radius direction of the circle where the fan-shaped structure is located, so that no matter how many powder feeding tubes distributed in the width direction of the laser beam channel 3 in the powder feeding cavity 4 and the width of the laser beam channel 3 are changed, the converging point of the laser beam and the converging point of the powder feeding cavity can be distributed in the same plane, but the powder cake formed at the outlet of the powder feeding cavity has a certain diameter and can be converged with the laser beam above the converging point, the laser beam is contacted with the powder cake before reaching the surface of the matrix, so that most of the energy of the laser beam is used for heating, melting and accelerating the powder particles in flight, only a very small amount of the energy of the laser beam can heat the matrix, the matrix is prevented from being overheated to greatly reduce the dilution rate, the deformation and the dilution rate of the matrix are reduced, the powder utilization rate and the processing efficiency can be greatly improved, and the effective components of the coating are not influenced by the matrix material, so that the corrosion-resistant and wear-resistant effects of the coating are improved.

Referring to fig. 1, 2, 3, 8 and 9, the cross section of the laser beam channel 3 is a semicircular structure or a half-square structure, that is, the laser beam channel 3 is an open half-open structure, and the laser beams can be converged at a point downward along the inner wall of the laser beam channel 3. The main part that powder pipe 401 was sent to cylindricality can be cylindrical send powder pipe or prismatic powder pipe, and the exemplification, and cylindricality send powder pipe 401 can be to triangular prism or quadrangular structure, the embodiment of the utility model provides a do not limit to this, but, the cylindricality send powder pipe 401's main part cross sectional shape the same, also need guarantee that cylindricality send powder pipe 401 to be close to laser beam convergent point's part needs in its length direction pipe diameter evenly distributed to guarantee that the powder evenly circulates before reacing laser beam convergent point.

Referring to fig. 1, 2, 3, 8, 9 and 10, a laser beam channel 3 according to an embodiment of the present invention is a tapered structure with an inverted configuration, wherein a taper of the laser beam channel is 1: 10-1: 5, preferably, a taper of the laser beam channel is 15:114, wherein the taper refers to a ratio between a difference between a radius of a large end and a radius of a small end and a height. Under the taper, the action time between the laser beam and the powder cake is longest, the utilization rate of the powder is highest, the dilution rate of the matrix is lowest, and the metallurgical bonding strength of the coating is high.

Referring to fig. 1, fig. 2, fig. 3, fig. 9, fig. 10, fig. 11 and fig. 12, the total number of the cylindrical powder feeding pipes 401 of the embodiment of the present invention is an odd number, the cylindrical powder feeding pipe 401 is located at the middle position and is the central powder feeding pipe 4011, the cylindrical powder feeding pipes located at both sides of the central powder feeding pipe 4011 are the side powder feeding pipes 4012, the distance between the outlet of the side powder feeding pipe 4012 and the outlet of the central powder feeding pipe 4011 is smaller than the distance between the inlet of the side powder feeding pipe 4012 and the inlet of the central powder feeding pipe 4011, that is, the powder discharging directions of the multiple cylindrical powder feeding pipes 401 arranged side by side are converged to the central position, and then the powder feeding effect of the powder feeding chamber can be ensured. Referring to fig. 11, an included angle b between the central line of the side powder feeding tube 4012 and the central line of the central powder feeding tube 4011 is 5 to 30 °, the powder feeding cavity in the included angle range has the best converging effect, and the spraying effect of ultra-high speed laser cladding can be ensured by matching with the included angle between the powder feeding cavity and the laser beam channel.

Referring to fig. 4, 7, 8, 9, 11 and 12, a cylindrical powder feeding tube 401 of an embodiment of the present invention is composed of 4 sections of cylindrical tube assemblies with different diameters, and the diameters of the cylindrical tubes decrease from top to bottom in sequence, wherein the length of the cylindrical tube with the smallest diameter is longest.

Referring to fig. 1, fig. 2, fig. 3, fig. 6, fig. 7, the utility model discloses a paraxial powder feeding device is provided with cooling chamber 5 in the outside of device body 1, and cooling chamber 5 is the rectangle inner chamber that the slope set up, is provided with coolant liquid circulating pipe mounting hole 6 on the lateral wall of rectangle inner chamber, and coolant liquid circulating pipe mounting hole 6 is used for installing the coolant liquid circulating pipe and realizes the quick cooling of paraxial powder feeding device of the embodiment of the utility model.

Referring to fig. 1 to 12, the embodiment of the present invention provides a paraxial powder feeding device, which adopts a split structure for fixing the device body by mutual splicing in order to reduce the processing difficulty of the device body. Specifically, referring to fig. 1, fig. 3, fig. 4, fig. 6, fig. 7, fig. 8, fig. 9, fig. 10, fig. 11, and fig. 12, an embodiment of the present invention provides an apparatus body 1 including an apparatus central body 101 and a side cover 102 fixed on one side of the apparatus central body 101, wherein the powder feeding cavity 4 is distributed along a splicing surface between the side cover 102 and the apparatus central body 101.

Referring to fig. 9, 10, 11 and 12, the device central body 101 and the side cover 102 according to the embodiment of the present invention may be separately processed and fixed to each other by screws or bolts. Meanwhile, the device body 1 adopting the split structure is used for reducing the processing difficulty of the powder feeding cavity formed by the cylindrical powder feeding pipe 401. Referring to fig. 7, 9, 10, 11 and 12, the cylindrical powder feeding tube 401 is a split structure, and the cylindrical powder feeding tube 401 includes a left tube 4013 and a right tube 4014 that are mated with each other, where the left tube 4013 is located on the end surface of the device central body 101 opposite to the side cover 102, and the right tube 4014 is located on the end surface of the side cover 102 opposite to the device central body 101.

That is, referring to fig. 7, 8, 9, 10, 11 and 12, the cylindrical powder feeding tube 401 is divided into a left part and a right part which are spliced and matched with each other, a half of the cylindrical powder feeding tube 401 can be processed on the splicing surface of the device central body 101, the rest of the cylindrical powder feeding tube 401 can be processed on the splicing surface of the side cover, and then the cylindrical powder feeding tube 401 is formed after being spliced with each other. Because the cylindrical powder feeding pipe 401 is a thin pipe which is obliquely arranged, if a splicing structure is not adopted, the processing difficulty is extremely high, and even the qualified cylindrical powder feeding pipe cannot be processed, the split processing of the cylindrical powder feeding pipe is realized by adopting the cylindrical powder feeding pipe with the split structure, the processing difficulty of the cylindrical powder feeding pipe can be greatly reduced, and the processing precision of the cylindrical powder feeding pipe is improved.

Referring to fig. 1, 2, 3, 4 and 5, the paraxial powder feeding device of the embodiment of the present invention adopts a top installation fixing manner, and the connecting device 2 is disposed at the upper end of the device body 1, i.e. the connecting device 2 is fixed at the upper portion of the device body 1, wherein the connecting device 2 can be integrally formed with the device central body 101 or separately processed, and the connecting device 2 can be welded and fixed at the upper portion of the device central body 101 or fixed at the device central body 101 by screw connection or bolt connection. Referring to fig. 1, 2, 7 and 8, the connecting device 2 is provided with a connecting flange 201, the connecting flange 201 is used for fixing with other components, and the laser beam channel 3 penetrates through the device body 1 and the connecting device 2.

Referring to fig. 1, 7 and 8, a cooling cavity 5 is arranged outside the powder feeding cavity 4, a cooling cavity cover 501 is fixed on the side surface of the device body 1, the cooling cavity 5 is a cooling liquid circulation space formed by mutually splicing the cooling cavity cover 501 and the device body 1, and referring to fig. 1 and 7, the cooling cavity cover 501 is fixed on the device body 1 by bolts or screws, so that the processing difficulty of the cooling cavity can be reduced. Illustratively, the left cooling chambers 5 are each rectangular chambers. The connecting device 2 comprises a base 202 fixed on the device body, a connecting flange 201 fixed on the base 202, and end covers 203 respectively fixed on the device body 1 and the cooling cavity cover 501, wherein the end covers 203 are provided with powder feeding head mounting holes 204, and the powder feeding head mounting holes 204 are communicated with a cylindrical powder feeding pipe 401. The powder feeding head mounting hole 204 is used for mounting and connecting an external powder feeding head. The external powder feeding head 7 can be mounted in the powder feeding head mounting hole 204 by screw connection.

The embodiment of the utility model provides a paraxial powder feeding device, because its laser beam passageway is open structure, die the laser beam restriction in this passageway not, the laser beam passageway only provides a guide effect for laser beam, and then relative laser beam can realize the powder feeding of arbitrary angle, not only can realize the hypervelocity laser cladding, can also realize ordinary laser cladding, and the working method is nimble and adaptability is wide.

It is apparent that those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if such modifications and variations of the embodiments of the present invention fall within the scope of the claims and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. The paraxial powder feeding device is characterized by comprising a device body and a connecting device fixed on the device body, wherein the connecting device is used for fixing the paraxial powder feeding device with other components, a powder feeding cavity is arranged on the device body, and an included angle between the powder feeding cavity and a vertical surface is 5-45 degrees.

2. The paraxial powder feeding device according to claim 1, wherein the device body is provided with a laser beam channel having an inverted conical structure, the powder feeding cavity is arranged on one side of the laser beam channel, and an included angle between the powder feeding cavity and the laser beam channel is 5-45 degrees; the powder feeding cavity is of a cylindrical structure, and the convergence point of the section center line of the powder feeding cavity and the section center line of the laser beam channel is in the same plane.

3. The paraxial powder feeding device according to claim 2, wherein the cross section of the laser beam channel has a semicircular structure or a semi-square structure, and the powder feeding chamber comprises a plurality of cylindrical powder feeding pipes arranged side by side.

4. The paraxial powder feeding device according to claim 3, wherein the total number of the cylindrical powder feeding pipes is an odd number, the cylindrical powder feeding pipe located at the middle position is a central powder feeding pipe, the cylindrical powder feeding pipes located at both sides of the central powder feeding pipe are side powder feeding pipes, and the distance between the outlet of the side powder feeding pipe and the outlet of the central powder feeding pipe is smaller than the distance between the inlet of the side powder feeding pipe and the inlet of the central powder feeding pipe.

5. The paraxial powder feed apparatus of claim 4 wherein the angle between the centerline of the lateral powder feed tube and the centerline of the central powder feed tube is between 5 ° and 30 °.

6. The paraxial powder feeding apparatus as claimed in claim 3, wherein the cylindrical powder feeding tube is composed of 4 sections of cylindrical tube assemblies each having a different diameter, and the diameters of the cylindrical tubes decrease from top to bottom in order.

7. The paraxial powder feed device of claim 3 wherein the device body comprises a device central body and a side cover fixed to one side of the device central body, wherein the powder feed cavities are distributed along a splicing plane between the side cover and the device central body.

8. The paraxial powder feed device of claim 7, wherein the cylindrical powder feed tube is a split structure, and comprises a left tube and a right tube which are matched with each other, wherein the left tube is located on the end surface of the device central body opposite to the side cover, and the right tube is located on the end surface of the side cover opposite to the device central body.

9. The paraxial powder feeder according to claim 7, wherein a cooling chamber is provided outside the powder feeding chamber, the connecting device is provided at an upper end of the feeder body, the connecting device is provided with a connecting flange for fixing with other parts, and the laser beam passage penetrates through the feeder body and the connecting device.

10. The paraxial powder feeding device according to claim 9, wherein a cooling chamber cover is fixed to a side surface of the device body, the cooling chamber cover and the device body are matched with each other to form the cooling chamber, a cooling pipe mounting hole is formed in the cooling chamber cover, the connecting device comprises a base fixed to the device body, a connecting flange fixed to the base, and end covers fixed to the device body and the cooling chamber cover respectively, a powder feeding head mounting hole is formed in the end covers, and the powder feeding head mounting hole is communicated with the cylindrical powder feeding pipe.