Plasma spraying device for additive manufacturing

Abstract

The present invention relates to the field of plasma spraying technology, and in particular to a plasma spraying device for additive manufacturing, comprising a spray gun body, a support, and a focus hood, wherein the support is mounted on the spray gun body, and the focus hood is tapered as a whole, with one end being a small mouth end and the other end being a large mouth end, the large mouth end of the focus hood being connected to the support, and the inner surface of the focus hood being a hollow cone. The present invention changes the spray flame flow size and the spraying area through the focus hood, so that the plasma spray gun and the plasma spraying process have the small-size processing capability of additive manufacturing, effectively improves the spraying quality, and has a simple structure, and can be adapted to most industrial-grade plasma spray guns. The present invention installs a conical focus hood at the front end of an existing plasma spray gun, and realizes the convergence of the plasma flame flow at the small mouth end of the focus hood by setting the inner surface of the focus hood to a hollow cone, thereby changing the flame flow size and enabling it to have additive manufacturing capabilities.

Description

Technical Field

[0001] The invention relates to the field of plasma spraying, in particular to a plasma spraying device for additive manufacturing. Background Art

[0002] Plasma spraying is a technology for strengthening and modifying the surface of materials. By depositing coatings with different properties on the substrate, the substrate surface can be made to have properties such as wear resistance, corrosion resistance, high temperature oxidation resistance, electrical insulation, heat insulation, radiation protection, friction reduction and sealing. Plasma spraying technology uses a plasma arc driven by direct current as a heat source to heat powder materials such as ceramics and metals to a molten or semi-molten state, and sprays them at high speed onto the pre-treated workpiece surface to form a firmly attached surface coating.

[0003] Additive manufacturing (i.e. 3D printing) integrates multiple disciplines such as three-dimensional model design, material processing and forming, machinery, and automatic control. It is an advanced manufacturing technology based on the principle of discrete stacking and digital model files. It is an advanced manufacturing technology that manufactures physical parts by accumulating materials layer by layer from the bottom up. It is not restricted by the geometric shape and structure of the parts and can achieve rapid manufacturing of complex structural parts. Therefore, it has a wide range of uses in mold manufacturing, industrial design, aerospace, biomedicine and other fields. At present, according to the different types of materials, properties and carrying energy, additive manufacturing technology has derived different manufacturing methods, such as nanoparticle injection technology, arc additive manufacturing technology, directed energy deposition technology, molten deposition molding technology, etc.

[0004] Compared with additive manufacturing technology, plasma spraying is a surface engineering technology, that is, coatings with different functions are prepared on the surface of different substrates to meet their application requirements. Plasma spraying has a wide range of coating materials, high deposition rate, and large spray coverage. A larger spray coverage can significantly improve the efficiency of plasma spraying coating preparation, but at the same time limits the application of plasma spraying technology in small-scale additive manufacturing. For example, in the plasma spraying process, when nickel-based alloy powder is injected into the flame flow, the plasma flame flow will deposit a deposition layer with a width of 10-20 mm and a thickness of 10-50 microns after sweeping across the surface of the substrate. Such a large spray coverage cannot achieve small-scale manufacturing (for example, manufacturing blocks with a length, width, and height of 5 mm × 5 mm × 100 mm). In addition, the center of the plasma flame flow has a high speed and high temperature, and the speed and temperature gradually decrease from the center of the flame flow to the edge of the flame flow, which results in the powder particles at the center of the flame flow having a high temperature, a fast speed, and a good melting state, while the powder particles at the edge of the flame flow have a slow speed, a low temperature, and a poor melting state. When powder particles at different speeds, temperatures, and molten states are deposited onto the surface of the substrate, the coating microstructure will be uneven, and there will be many defects such as holes and cracks, which will reduce the quality of the coating.

[0005] As can be seen from the above, plasma spraying has a certain degree of similarity with existing additive manufacturing technology, but the process is difficult to be directly used for small-sized additive manufacturing processing. By improving the existing plasma spraying device, reducing the size of the flame flow and increasing the speed and temperature of the powder particles in the flame flow, the plasma spraying process can be used in additive manufacturing processing, greatly broadening the application range of the existing plasma spraying device. Summary of the invention

[0006] The purpose of the present invention is to provide a plasma spraying device for additive manufacturing, so that the plasma spraying device can be suitable for additive manufacturing processing and broaden the application scope of the plasma spraying equipment. The present invention realizes the function of additive manufacturing by simply modifying the plasma spraying device.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A plasma spraying device for additive manufacturing includes a spray gun body, a support, and a focus hood. The support is installed on the spray gun body. The focus hood is a hollow cone as a whole, with a small mouth end at one end and a large mouth end at the other end. The large mouth end of the focus hood is connected to the support, and the inner surface of the focus hood is a hollow cone.

[0009] Furthermore, it also includes a cooling component, which includes a water inlet pipe and a water outlet pipe. A water cooling chamber is provided inside the focusing hood. The focusing hood is also provided with a water inlet and a water outlet connected to the water cooling chamber. The water inlet is connected to the water inlet pipe, and the water outlet is connected to the water outlet pipe.

[0010] Furthermore, the support can be connected to the spray gun body and can be flexibly disassembled.

[0011] Furthermore, the installation distance between the focus hood and the spray gun body is adjustable.

[0012] Furthermore, the support includes a flat plate and a circular ring, a fixed support plate is provided on the circular ring, a sliding groove is opened on the fixed support plate, a movable support plate is provided at the large mouth end of the condenser, a sliding groove is also provided on the movable support plate, and the fixed support plate and the movable support plate are fixed by fasteners.

[0013] Furthermore, it also includes a flat spray nozzle, which is detachably mounted on the small opening end of the focusing hood, and is provided with a through hole.

[0014] Furthermore, the flat spray nozzle is detachably connected to the small opening end of the focusing hood by means of screws.

[0015] The present invention provides a plasma spraying device for additive manufacturing, which has the following beneficial effects:

[0016] (1) The present invention achieves additive manufacturing by installing a conical focusing hood at the front end of an existing plasma spray gun and setting the inner surface of the focusing hood to a hollow cone to achieve the focusing of the flame flow at the small opening end of the focusing hood.

[0017] (2) The present invention provides a replaceable flat spray nozzle at the small mouth end of the focusing hood, and replaces the flat spray nozzles of different calibers as needed to achieve additive manufacturing spraying effects of different calibers.

[0018] (3) The present invention can significantly improve the service life of the plasma spraying device by configuring the focusing hood as a cavity structure and cooperating with a cooling component to effectively achieve water cooling.

[0019] (4) The fixed support plate of the support with sliding grooves of the present invention cooperates with the movable support plate of the focus hood, and the use of fasteners can be combined to adjust the overlapping length of the fixed support plate and the movable support plate, so as to adjust the distance between the focus hood and the spray gun body, thereby determining the optimal working distance, and the adaptability is strong.

[0020] (5) The present invention utilizes a detachable support to fasten and connect the focus hood and the flat spray nozzle, which has a simple structure and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present invention;

[0022] Figure 2 is a cross-sectional view of the focus hood;

[0023] Figure 3 This is a schematic diagram of the overall structure of Embodiment 2 of the present invention;

[0024] Figure 4 It is a three-dimensional picture of a flat spray nozzle;

[0025] Figure 5 This is a cross-sectional view of a flat spray nozzle.

[0026] Explanation of the reference numerals: 1-spray gun body; 2-support; 21-flat plate; 22-ring; 23-fixed support plate; 3-collector hood; 31-movable support plate; 32-cavity; 33-water inlet; 33-water outlet; 4-cooling assembly; 41-water inlet pipe; 42-water outlet pipe; 5-flat spray nozzle; 51-through hole; 6-fastener. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0028] Example 1

[0029] like Figure 1 As shown, the present invention provides a plasma spraying device for additive manufacturing, including a spray gun body 1, a support 2, a focusing hood 3, and a cooling assembly 4.

[0030] The support 2 is arranged at the nozzle end of the spray gun body 1, and the focus hood 3 is cone-shaped as a whole, with a small mouth at one end and a large mouth at the other end. The large mouth end of the focus hood 3 is connected to the support 2, and the small mouth end of the focus hood 3 is the flame jet outlet.

[0031] In one embodiment, the support 2 is directly welded to the spray gun body 1. In another preferred embodiment, the support 2 can be detachably mounted on the spray gun body 1, for example, a connection notch is provided on the side end face of the spray gun body 1, and the support 2 is clamped to the spray gun body 1 through the connection notch, or a boss is provided on the side end face of the spray gun body 1, and the support 2 is clamped to the spray gun body 1 through the boss.

[0032] In a preferred connection mode between the focus hood 3 and the support 2, the support 2 is welded by a flat plate 21 and a circular ring 22, and a certain distance is maintained when installed with the spray gun body 1, so as to reduce the influence of the high temperature of the spray gun body 1, avoid thermal stress deformation, and ensure the service life of the support 2. Two symmetrically arranged fixed support plates 23 are arranged on the end face of the circular ring 22 of the support 2, and sliding grooves are provided on the fixed support plates 23. In cooperation with the fixed support plates 23, two symmetrically arranged movable support plates 31 are arranged at the large mouth end of the focus hood 3, and sliding grooves are also provided on the movable support plates 31. The sliding grooves of the fixed support plates 23 and the movable support plates 31 cooperate with the fasteners 6 to realize the connection between the focus hood 3 and the support 2. The fixed support plates 23 and the movable support plates 31 with sliding grooves are mainly used to adjust and maintain the distance between the plasma flame flow of the spray gun body 1 and the flat spray nozzle 5. The fastener 6 may be composed of a bolt, a nut, and a washer, wherein the bolt may pass through the sliding grooves of the fixed support plate 22 and the movable support plate 23 , and the working distance may be adjusted by adjusting the overlapping length between the fixed support plate 22 and the movable support plate 23 .

[0033] like Figure 2 As shown, the inner surface of the focus hood 3 is designed to be a hollow cone. By setting the inner surface of the focus hood 3 to be a hollow cone, the flame flow is focused at the outlet of the focus hood 3, thereby realizing additive manufacturing.

[0034] A cavity 32 is provided inside the collector 3, and a water inlet 33 and a water outlet 34 are also provided on the collector 3. The water inlet 33 and the water outlet 34 are connected to the cavity 32. The cooling component 4 includes a water inlet pipe 41 and a water outlet pipe 42. The water inlet pipe 41 is connected to the water inlet 33, and the water outlet pipe 42 is connected to the water outlet 34. Cooling water flows in from the water inlet pipe and flows out from the water outlet pipe through the internal channel, taking away the heat stored or directly acting on the collector 3, thereby achieving a water-cooling effect.

[0035] Example 2

[0036] like Figure 3 As shown, on the basis of Example 1, the plasma spraying device further includes a flat spraying nozzle 5, which is detachably arranged at the small mouth end of the focusing hood 3, and is provided with a through hole 51, and the through holes 51 of flat spraying nozzles 5 of different calibers are different in size. By arranging a detachable and replaceable flat spraying nozzle 5 at the small mouth end of the focusing hood 3, flat spraying nozzles 5 of different calibers can be replaced as needed to achieve different additive manufacturing spraying effects.

[0037] The detachable connection between the flat spray nozzle 5 and the focus cover 3 can be a detachable connection method existing in the prior art, such as snap connection, buckle connection, threaded connection, screw connection, etc. Preferably, the flat spray nozzle 5 is connected to the focus cover 3 by screws, which is firmly connected and easy to replace.

[0038] In a more preferred embodiment, the through hole 51 is tapered to further focus the flame flow and improve the additive manufacturing spraying effect.

[0039] It should be noted that the components of the plasma spraying device for additive manufacturing of the present invention are all universal standard parts or components known to those skilled in the art, and their structures and principles can be known to those skilled in the art through technical manuals or conventional experimental methods, ensuring that each device can operate normally, and no excessive restrictions are imposed here.

[0040] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A plasma spraying device for additive manufacturing, comprising a spray gun body (1), the spray gun body (1) being used to spray a plasma flame flow, characterized in that: It also comprises a support (2) and a focus hood (3), wherein the support (2) is detachably mounted on the spray gun body (1), the focus hood (3) is in a cone shape as a whole, with one end being a small mouth end and the other end being a large mouth end, the large mouth end of the focus hood (3) is connected to the support (2), and the inner surface of the focus hood (3) is a hollow cone surface; It also comprises a cooling assembly (4), the cooling assembly (4) comprising a water inlet pipe (41) and a water outlet pipe (42), a cavity (32) being provided inside the focus cover (3), the focus cover (3) also being provided with a water inlet (33) and a water outlet (34) communicating with the cavity (32), the water inlet (33) being connected to the water inlet pipe (41), and the water outlet being connected to the water outlet pipe (42).

2. The plasma spraying device for additive manufacturing according to claim 1, characterized in that: The installation distance between the focusing hood (3) and the spray gun body (1) is adjustable.

3. The plasma spraying device for additive manufacturing according to claim 2, characterized in that: The support (2) comprises a flat plate (21) and a circular ring (22); a fixed support plate (23) is provided on the circular ring (22); a sliding groove is provided on the fixed support plate (23); a movable support plate (31) is provided at the large mouth end of the focus hood (3); a sliding groove is also provided on the movable support plate (31); the fixed support plate (23) and the movable support plate (31) are fixed by a fastener (6).

4. The plasma spraying device for additive manufacturing according to any one of claims 1 to 3, characterized in that: It also comprises a flat spray nozzle (5), the flat spray nozzle (5) being detachably mounted on the small opening end of the focusing hood (3), and a through hole (51) being provided on the flat spray nozzle (5).

5. The plasma spraying device for additive manufacturing according to claim 4, characterized in that: The flat spray nozzle (5) is detachably connected to the small opening end of the focusing cover (3) via screws.

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