CN107587132A - A kind of multifunctional coaxial powder feeding high-rate laser spray equipment and application - Google Patents

Abstract

The invention relates to a laser spraying device for coaxial powder feeding, in particular to a multifunctional coaxial powder feeding high-speed laser spraying device and its application. It mainly includes laser cavity tube, nozzle, movable retaining ring, at least one powder feeding tube and at least one high-pressure gas tube; high-pressure gas enters the laser cavity tube through the high-pressure gas tube, and is output coaxially with the laser beam through the nozzle at super high speed, and the spray powder passes through The powder feeding tube and the outflow from the gap move coaxially and in the same direction as the laser to the surface of the substrate at high speed. Through the powder feeding device, the spray powder can move coaxially and in the same direction as the laser at an ultra-high speed, which effectively solves the problems of high cost of the traditional powder feeding device, large laser energy loss, and cumbersome equipment use procedures, and further solves the problem of insufficient utilization of the spray powder. Sufficient, pollute the environment and other issues, the device can also be applied in laser cladding, metal 3D printing.

Description

A multi-functional coaxial powder feeding high-speed laser spraying device and its application

technical field

The invention relates to a laser spraying device for coaxial powder feeding, in particular to a multifunctional coaxial powder feeding high-speed laser spraying device. By adjusting relevant parameters, the device can be used for laser spraying, laser cladding and metal 3D printing.

Background technique

Laser spraying technology is a method of using laser to heat the spray powder to a melted or semi-melted state, and deposit it at a certain speed on the surface of the pretreated substrate to form a coating. Laser thermal spraying technology can create a special working surface on the surface of ordinary materials, so that it can achieve a series of functions such as anti-corrosion, wear-resistant, high-temperature resistance, anti-oxidation, and electrical conductivity. Supersonic laser spraying is based on laser spraying technology, using compressed gas as the acceleration medium, the spray powder collides with the surface of the substrate at a super high speed under the action of compressed gas, the surface of the substrate and the spray powder undergo plastic deformation at the same time, and at the same time the spray powder and The substrate undergoes thermal softening under the action of laser radiation, rapidly forming a metallurgically bonded surface coating. Compared with traditional laser spraying technology, high-speed laser spraying has high metallurgical bonding efficiency, high coating density and strong bonding between spray powder and substrate.

High-speed laser spraying equipment mainly includes five parts: laser, mechanical numerical control equipment, powder feeding device, water cooler, and high-pressure gas generator. Among them, the powder feeding device controls the spray powder flow, movement path and speed, and is the core component of the whole set of equipment. The traditional powder feeding device adopts Laval nozzle to accelerate gas powder mixing, and the accelerated spray powder flies out of the nozzle to the surface of the substrate. The traditional powder feeding device and the laser head adopt separate or integrated structures. FIG. 1 is a traditional separated powder feeding device, including a Laval nozzle 11 , a substrate 12 and a laser head 13 . Fig. 2 is a traditional integrated powder feeding device, including a laser head 21, a substrate 22, and a Laval nozzle 23, wherein one or more nozzles can be uniformly or unevenly arranged around the laser head. In the actual application of the traditional powder feeding device, there are the following problems: (1) The high-speed flowing spray powder inside the nozzle rubs against the inner wall of the nozzle, which causes serious wear and tear inside the nozzle after long-term use, and the nozzle needs to be replaced regularly, and the cost is high; (2) The light output It is necessary to adjust and confirm the relative position of the laser head and the Laval nozzle to ensure that the laser spot completely covers the powder spot of the spray powder on the surface of the substrate. The debugging process is cumbersome and the time cost is high, which is not suitable for industrial processing. When the angle collides with the surface of the substrate, part of the metal powder overflows the powder spot area at the moment of the collision, resulting in low utilization rate of the spray powder and pollution to the surrounding environment of processing, which affects the health of equipment operators in severe cases; (4) Laser and multiple beams of metal powder intersect on the substrate On the surface, affected by the thickness of the metal powder, the laser energy cannot be fully absorbed, the laser energy is lost more, and the efficiency of the whole machine is low.

Contents of the invention

The purpose of the present invention is to provide a multi-functional coaxial powder feeding high-speed laser spraying device, through which the powder feeding device can realize the coaxial and same direction movement of the spray powder and the laser at an ultra-high speed, effectively solving the problem of high cost of the traditional powder feeding device, laser The problems of large energy loss and cumbersome equipment use procedures further solve the problems of insufficient utilization of spray powder and environmental pollution. The device can also be applied to laser cladding and metal 3D printing.

The technical solution of the present invention is to provide a multi-functional coaxial powder feeding high-speed laser spraying device, which is special in that it includes a laser cavity 1, a nozzle 2, a movable retaining ring 4, at least one powder feeding pipe 3 and at least A high-pressure gas pipe 5;

The above-mentioned laser cavity 1 is divided into three sections, which are the laser incident section, the middle section and the laser exit section in sequence along the laser incident direction;

The above-mentioned high-pressure gas pipe 5 communicates with the inner cavity of the laser cavity tube 1;

The above-mentioned nozzle 2 is a Laval nozzle or a Laval-like nozzle, and the nozzle 2 is embedded in the inner wall of the laser cavity 1;

The above-mentioned powder feeding tube 3 is arranged on the tube wall of the laser cavity tube 1, and the angle between the powder feeding tube 3 and the axial center axis of the laser cavity tube 1 is greater than 0 and less than 90 degrees;

The above-mentioned movable retaining ring 4 is detachably connected to the end face of the middle section of the laser cavity tube 1, and there is a first annular cone-like or cone-shaped gap 8 between the movable retaining ring 4 and the outer wall of the laser exit section of the laser cavity tube 1. The size of the first annular cone-like or cone-shaped gap 8 can be adjusted by adjusting the position of the movable retaining ring 4, thereby controlling the spray powder flow rate; the above-mentioned first ring-like cone-like or cone-shaped gap 8 communicates with the powder feeding pipe 3 ;

The laser cavity 1, the nozzle 2 and the movable retaining ring 4 are coaxial;

The high-pressure gas enters the laser cavity 1 through the high-pressure gas pipe 5, and is output coaxially with the laser beam through the nozzle 2 at an ultra-high speed. The spray powder flows out through the powder feeding pipe 3 and the gap and moves coaxially with the laser to the surface of the substrate at high speed.

Preferably, the above-mentioned Laval-like nozzle is divided into three parts, which are the inlet section, the throat and the outlet section in turn, the size of the inlet section gradually decreases from the inlet end to the connection between the throat and the throat; the outlet section is connected to the throat, The size of the outlet section increases from the junction with the throat to the size of the outlet end. That is, the nozzles of the present invention are not limited to conventional Laval nozzles.

Preferably, the area of the throat of the above-mentioned nozzle is larger than the cross section of the laser beam there; the gap near the bottom of the first annular cone-like gap is larger than the gap near the top of the cone, and the outlet end of the powder feeding pipe 3 communicates with the gap at the bottom of the cone .

Preferably, the above-mentioned powder feeding pipes 3 are evenly distributed along the circumferential direction of the middle section of the laser cavity 1 .

Preferably, the device of the present invention also includes a protective gas nozzle 6, which is detachably connected to the wall of the laser cavity tube 1, so that the movable retaining ring 4 is located between the protective gas nozzle 6 and the laser cavity tube 1; The air nozzle 6 is provided with a protective gas pipe 7, and there is a second annular conical gap 9 between the protective gas nozzle 6 and the movable retaining ring 4, the second annular conical gap 9 communicates with the protective gas pipe 7, and the second annular cone The size of the shaped gap 9 can be adjusted by adjusting the positions of the shielding gas nozzle 6, the laser cavity tube and the movable retaining ring 4, thereby controlling the air pressure when the shielding gas pressure flows through.

Preferably, the protective gas nozzle 6 is coaxial with the laser cavity 1 .

Preferably, the end surface of the middle section of the laser cavity tube 1 is stepped, the above-mentioned movable retaining ring 4 cooperates with the low-level plane, and is screwed with the low-level plane; the shielding gas nozzle 6 is screwed with the high-level plane.

Preferably, the protective gas pipes 7 are evenly distributed along the circumferential direction of the protective gas nozzle 6 .

Preferably, the inner diameter of the middle section of the laser cavity tube 1 is the same as the inner diameter of the laser incident section, and the outer diameter of the middle section is greater than the outer diameter of the laser incident section; the outer diameter of the laser cavity tube 1 laser exit section is smaller than the outer diameter of the middle section. The inner diameter of the middle section, and the outer diameter of the laser output section is gradually reduced to be equal to its inner diameter;

The above-mentioned powder feeding tube 3 is located in the tube wall of the middle section of the laser cavity tube 1;

The nozzle 2 is embedded in the middle section of the laser cavity 1 and the inner wall of the laser emitting section.

The present invention also provides an application of the above-mentioned multifunctional coaxial powder feeding high-speed laser spraying device in laser cladding, laser spraying and metal 3D printing.

The beneficial effects of the present invention are:

1. After the high-pressure gas is accelerated through the nozzle, the spray powder is accelerated outside the powder feeder to avoid the high-speed flowing spray powder from causing wear to the powder feeder components;

2. The spray powder flows out through the powder feeding channel, and is affected by the high-speed airflow to realize the coaxial and same direction movement of the laser. The operator does not need to correct and adjust the equipment when using the equipment, and the operation is time-saving and convenient;

3. The spray powder is irradiated by laser light before it collides with the substrate, absorbing light energy to soften or melt, fully utilizing the laser energy and high efficiency;

4. Under the action of high-pressure air flow and protective gas, the spray powder hits the surface of the substrate at a vertical angle in the softened state and quickly combines with the surface of the substrate, without powder spillage, high utilization rate, and no pollution to the surrounding environment;

5. The present invention can control the spray powder flow rate and the protective gas pressure through the adjustment of the thread tightness between the parts, which is flexible, convenient and practical, and can be popularized in industrial applications;

6. By adjusting the air pressure and powder feeding volume, the device can be used for laser cladding and metal 3D printing.

Description of drawings

Figure 1 is a schematic diagram of the structure of a traditional separated powder feeding device. In the figure, 11-Laval nozzle, 12-substrate, 13-laser head;

Figure 2 is a schematic structural diagram of a traditional integrated powder feeding device. In the figure, 21-laser head, 22-substrate, 23-Laval nozzle or Laval-like nozzle;

Figure 3 is a schematic structural diagram of the embodiment, in which, 1-laser cavity tube, 2-nozzle, 3-powder feeding tube, 4-movable retaining ring, 5-high pressure air pipe, 6-protection gas nozzle, 7-protection gas pipe , 8-the first annular cone-like or cone-shaped void, 9-the second annular cone-shaped void;

4 is a schematic diagram of the working principle of the present invention. In the figure, 101-high-pressure airflow, 102-laser beam, 201-spray powder, 301-protective airflow, 4-substrate, 5-sprayed layer.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As can be seen from Figure 3, the multi-functional high-speed laser spraying coaxial powder feeding device of this embodiment includes a laser cavity tube 1, a nozzle 2, a powder feeding tube 3, a movable retaining ring 4, a high-pressure air pipe 5, a protective gas nozzle 6 and a protective gas nozzle. The air pipe 7; wherein the laser cavity 1, the nozzle 2, the movable retaining ring 4 and the protective gas nozzle 6 are coaxial.

The laser cavity 1 can be divided into three sections, which are the laser incident section, the middle section and the laser exit section in sequence along the laser exiting direction, wherein the inner diameter of the middle section is the same as that of the laser incident section, and the outer diameter of the middle section is larger than that of the laser incident section The outer diameter of the laser exit section is smaller than the outer diameter of the middle section and greater than the inner diameter of the middle section, and its outer diameter gradually decreases to be equal to its inner diameter;

The high-pressure gas pipe 5 is located at the upper part of the laser cavity tube. In this example, there are two high-pressure gas tubes 5, which are located at the upper part of the laser cavity tube 1 at a circumferential interval of 180° and communicate with the inner cavity of the laser cavity tube 1;

The nozzle 2 is a Laval nozzle or a Laval-like nozzle. In this example, the nozzle 2 is a Laval nozzle, which is embedded in the inner wall of the laser exit end of the laser cavity tube 1; the exit end here can be understood as the middle section and the laser exit section; the nozzle 2 The shape of the throat position of the contraction section is circular and the area of the throat is greater than the cross section of the laser beam; in other embodiments, the shape of the throat can be a direction or other arbitrary shapes; the actual inner hole wall of the nozzle 2 is a curved surface of a certain shape , such as a trumpet shape, rather than the straight line segment shown in Figure 3; the high-pressure gas enters the laser cavity tube 1 through the high-pressure gas pipe 5, and is accelerated and ejected through the nozzle 2 at a relatively high speed;

The powder feeding tube 3 is located on the tube wall of the laser cavity tube 1. In this embodiment, there are two powder feeding tubes 3, which are located on both sides of the tube wall of the middle section of the laser cavity tube 1 at a circumferential interval of 180°, and are connected to the laser cavity tube 1. The included angle between the axial central axes of the cavity tube 1 is greater than 0 and less than 90°; in other embodiments, there may be multiple powder feeding tubes 3;

The end face of the middle section of the laser cavity tube 1 (the end face refers to the end face close to the laser exit section) is stepped, and the movable retaining ring 4 is matched with the low-level plane and connected with the low-level plane by threads; the protective gas nozzle 6 is connected with the high-level plane. Flat threaded connection. In other embodiments, other arbitrary detachable connection methods are also possible, such as clamping, etc.; the movable retaining ring 4 is located between the protective gas nozzle 6 and the laser cavity tube 1; the protective gas tube 7 is arranged on the protective gas nozzle 6, In this embodiment, there are two shielding gas tubes 7, and they are located on the shielding gas nozzle 6 at a circumferential interval of 180°; there is a first annular cone-like or cone-shaped gap between the movable stop ring 4 and the laser exit section of the laser cavity tube 1 8. The gap near the bottom of the cone is larger than the gap near the top of the cone (in other embodiments, it can also be an annular cone-shaped gap), and the outlet end of the powder feeding pipe 3 communicates with the gap at the bottom of the cone. By adjusting the tightness of the thread of the movable retaining ring 4 and the laser cavity tube 1, the size of the first annular cone-like or conical gap 8 is adjusted to control the flow of spraying powder; between the protective gas nozzle 6 and the movable retaining ring 4 There is a second annular conical gap 9, which communicates with the protective gas pipe 7; by adjusting the thread tightness of the protective gas nozzle 6, the movable retaining ring 4 and the laser cavity tube 1, the size of the second annular conical gap 9 is adjusted, To control the protective gas pressure;

The high-pressure gas enters the laser cavity 1 through the high-pressure gas pipe 5, and is accelerated and output coaxially with the laser beam through the Laval nozzle 2 at a supersonic speed. The spray powder flows out through the powder feeding pipe 3 and the gap and moves to the substrate coaxially and at high speed with the laser. surface.

The working principle of the present invention is further explained with reference to FIG. 4 . The high-pressure gas flow 101 is output coaxially with the laser beam 102 through the Laval nozzle 2 in the laser cavity 1 . The spray powder 201 flows out through the powder feeding pipe 3 and the gap, and is affected and accelerated by the high-pressure airflow 101. The spray powder 201 and the laser move coaxially and in the same direction to the surface of the substrate 4 at a high speed. The particles soften and quickly combine with the surface of the substrate that is also irradiated by the laser, and deposit on the surface of the substrate to form a tight spray coating5. The shielding gas 301 forms a circle of shielding gas curtain outside the spraying path to further prevent the spraying powder from splashing out.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (10)

1. A kind of 1. multifunctional coaxial powder feeding high-rate laser spray equipment, it is characterised in that：Including laser lumen (1), nozzle (2), Movable collet (4), at least one powder feeding pipe (3) and at least one high-pressure air pipe (5)；

   The laser lumen (1) is divided into three sections, and respectively being laser light incident section, interlude and laser along laser light incident direction goes out Penetrate section；

   The high-pressure air pipe (5) connects with laser lumen (1) inner chamber；

   The nozzle (2) is Laval nozzle or class Laval nozzle, and nozzle (2) is embedded in the inwall of laser lumen (1)；

   The powder feeding pipe (3) is arranged on the tube wall of laser lumen (1), powder feeding pipe (3) and laser lumen (1) axial centre axle it Between angle be more than 0 be less than 90 degree；

   The movable collet (4) is detachably connected on the end face of laser lumen (1) interlude, movable collet (4) and laser There is first annular class taper or taper space (8), the first annular class taper between the outer wall of lumen (1) laser emitting section Or taper space (8) are sized to be adjusted by the position of regulation activity collet (4)；The first annular class taper Or taper space (8) communicate with powder feeding pipe (3)；

   Laser lumen (1), nozzle (2) and movable collet (4) three are coaxial；

   Gases at high pressure are entered in laser lumen (1) by high-pressure air pipe (5), pass through nozzle (2) and laser beam with ultraspeed Coaxial output, spray coating powder move to matrix surface by powder feeding pipe (3) and space outflow with laser coaxial same-directional high-speed.
2. 2. multifunctional coaxial powder feeding high-rate laser spray equipment according to claim 1, it is characterised in that：The class Bearing score You are divided into three parts by nozzle, respectively are entrance, throat and outlet section, the size of entrance is gradually decrease to from arrival end Throat is connected with throat；Outlet section is connected with throat, and the size of outlet section gradually increases from connecting portion to port of export size.
3. 3. multifunctional coaxial powder feeding high-rate laser spray equipment according to claim 2, it is characterised in that：The nozzle The area of throat is more than the cross section of laser beam at this；First annular class taper space is more than close to cone close to the gap at cone bottom The gap on top, the port of export of powder feeding pipe (3) connect with cone bottom gap.
4. 4. according to any described multifunctional coaxial powder feeding high-rate laser spray equipments of claim 1-3, it is characterised in that：It is described Powder feeding pipe (3) is circumferentially uniformly distributed along laser lumen (1) interlude.
5. 5. multifunctional coaxial powder feeding high-rate laser spray equipment according to claim 4, it is characterised in that：Also include protection Valve (6), the protection valve (6) are detachably connected on laser lumen (1) tube wall so that movable collet (4) is positioned at guarantor Protect between valve (6) and laser lumen (1)；Protection tracheae (7), protection valve (6) and active catch are provided with protection valve (6) There is the second annular taper space (9) between feed ring (4), the second annular taper space (9) communicates with protection tracheae (7), The second annular taper space (9) is sized to by adjusting protection valve (6) and laser lumen and movable collet (4) Position be adjusted.
6. 6. multifunctional coaxial powder feeding high-rate laser spray equipment according to claim 5, it is characterised in that：The protection gas Mouth (6) and laser lumen (1) are coaxial.
7. 7. multifunctional coaxial powder feeding high-rate laser spray equipment according to claim 6, it is characterised in that：Laser lumen (1) end face of interlude is stepped that the movable collet (4) coordinates with low order plane, and is connected with low order flat thread； Protection valve (6) is connected with high-order flat thread.
8. 8. multifunctional coaxial powder feeding high-rate laser spray equipment according to claim 7, it is characterised in that：The protection gas Pipe (7) is circumferentially uniformly distributed along protection valve (6).
9. 9. multifunctional coaxial powder feeding high-rate laser spray equipment according to claim 4, it is characterised in that：Laser lumen (1) internal diameter of interlude is identical with the internal diameter of laser light incident section, and the external diameter of interlude is more than the external diameter of laser light incident section；Laser The external diameter of lumen (1) laser emitting section be less than interlude external diameter be more than interlude internal diameter, and the external diameter of laser deferent segment by It is decrescence as low as equal with its internal diameter；

   The powder feeding pipe (3) is located in the tube wall of laser lumen (1) interlude；

   The nozzle (2) is embedded in laser lumen (1) interlude and the inwall of laser emitting section.
10. 10. any described multifunctional coaxial powder feeding high-rate laser spray equipments of claim 1-9 are in laser melting coating, laser spraying And the application in metal 3D printing.