A three-beam wire and powder hybrid laser cladding system

Abstract

The present invention discloses a three-beam wire and powder hybrid laser cladding system, which includes a three-beam wire and powder hybrid laser cladding nozzle, a laser, a robot, first and second cladding material conveying devices, a nitrogen generator, and a water cooling device. The laser outputs a laser beam, and the incident laser is converted into a hollow three-beam by the three-beam wire and powder hybrid laser cladding nozzle; the robot can control the movement trajectory of the cladding nozzle through a controller; the cladding material conveying device conveys the cladding material to the cladding area through the cladding nozzle and ensures the precise coupling of the light and the cladding material; the nitrogen generator conveys the manufactured nitrogen to the cladding area through the cladding nozzle, and is also coaxial with the cladding material through the internal channel to ensure the accurate coupling of the light, the cladding material and the gas, prevent the formed part from oxidation and protect the internal lens of the cladding nozzle; the water cooling device mainly conveys cooling water to the laser and the internal lens of the cladding nozzle to ensure the timely cooling of the optical lens and prevent damage.

Description

Technical Field

[0001] The present invention belongs to the field of laser additive manufacturing, and particularly relates to a laser cladding system. Background Art

[0002] Laser cladding is a laser surface modification technology. A cladding material (powder feeding, wire feeding, pre-placement, etc.) is added to the surface of a workpiece (or substrate material). Through high-energy density laser heating, the cladding material and a thin layer of the substrate surface metal quickly reach a molten state. At this time, relying on the heat conduction of the workpiece itself, it rapidly solidifies and crystallizes into a cladding layer to obtain a modified layer or repair layer with metallurgical bonding to the substrate material, a low dilution rate, and various characteristics. Compared with traditional surface treatment technologies such as surfacing, thermal spraying, and electroplating, it has many advantages, such as a wide range of applicable material systems, controllable dilution rate of the cladding layer, metallurgical bonding between the cladding layer and the substrate, small thermal deformation of the substrate, and easy automation of the process. Therefore, since the 1980s, laser cladding technology has received extensive attention at home and abroad and has been applied in many industrial fields. Summary of the Invention

[0003] The purpose of the present invention is to provide a three-beam wire-powder hybrid laser cladding system. This laser cladding system can ensure uniform heat when the cladding material melts, which helps to improve the metallurgical bonding between the cladding layer and the workpiece, as well as improve the surface quality and obtain a smaller dilution rate. By changing the combination of the cladding materials (wire, powder), multi-material co-laser cladding is realized, which helps to improve the quality and mechanical properties of the formed part.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A three-beam wire-powder hybrid laser cladding system, comprising a workbench for placing a workpiece. Above the workbench is a three-beam wire-powder hybrid laser cladding nozzle. It also includes a controller, a robot, a laser, a water cooling device, a first cladding material conveying device, a nitrogen generator, and a second cladding material conveying device. The controller is connected to the robot, the laser, the water cooling device, the first cladding material conveying device, the nitrogen generator, and the second cladding material conveying device to control the operation of each device. The robot is connected to the three-beam wire-powder hybrid laser cladding nozzle to control its movement trajectory, realizing movement in the X-axis, Y-axis, and Z-axis spaces. The laser emits a laser beam, and the incident laser beam is converted into three beams by the three-beam wire-powder hybrid laser cladding nozzle and projected onto the workpiece. The first cladding material conveying device conveys the first cladding material to the three-beam wire-powder hybrid laser cladding nozzle and transports it to the workpiece through the three-beam wire-powder hybrid laser cladding nozzle. The second cladding material conveying device conveys the second cladding material to the three-beam wire-powder hybrid laser cladding nozzle and transports it to the workpiece through the three-beam wire-powder hybrid laser cladding nozzle. The three-beam wire-powder hybrid laser cladding nozzle focuses the three beams onto the workpiece to form a cladding area, and at the same time transports the first cladding material and the second cladding material to the cladding area. The water cooling device transports cooling water to the laser and the three-beam wire-powder hybrid laser cladding nozzle. The nitrogen generator transports the manufactured nitrogen to the cladding area through the three-beam wire-powder hybrid laser cladding nozzle.

[0006] Further, the three-beam wire-powder hybrid laser cladding nozzle includes a support frame. Above the support frame, there is a triangular prism and three focusing lenses. The three focusing lenses are arranged circumferentially on the three projection light paths of the triangular prism. On the support frame, a reflection light through-hole is opened below the focusing lenses. The incident laser beam is reflected into three beams by the triangular prism and the three focusing lenses and projected and focused onto the workpiece through the reflection light through-hole. A nozzle for conveying the first cladding material is fixed below the support frame.

[0007] Further, a material channel connection bracket is installed below the nozzle. At the central position of the material channel connection bracket, there is a nozzle channel. The nozzle is arranged in the nozzle channel. Around the nozzle channel, there are three material pipes for conveying the second cladding material. The material pipes are fixed in the material channel connection bracket. On the material channel connection bracket, there are also three reflection light channels, which are arranged in sequence between every two of the three material pipes. The three beams are respectively projected and focused onto the workpiece through the corresponding reflection light channels. The nozzle and the three material pipes are coaxially arranged with the three beams.

[0008] Preferably, the defocus amount of the three-beam wire-powder hybrid laser cladding nozzle is negative defocus; the distance in the vertical direction of the focus of the three beams relative to the workpiece surface is the defocus amount; when the focus is located below the workpiece surface, it is negative defocus.

[0009] Preferably, the three beams are projected onto the workpiece to form three independent light spots, and the circumcircle of the three light spots can envelope the area where the first cladding material and the second cladding material are located, and the first cladding material and the second cladding material are located outside the three independent light spots.

[0010] The present invention has the following beneficial effects:

[0011] In the system of the present invention, the laser beam output by the system laser is converted into a hollow three-beam through the internal optical path conversion system of the three-beam wire-powder hybrid laser cladding nozzle; the robot can control the movement trajectory of the cladding nozzle through the controller to realize the movement in the X-axis, Y-axis, and Z-axis spaces; the cladding material conveying device can convey the cladding material to the cladding area through the internal channel of the cladding nozzle, and ensure the precise coupling of light and cladding material through the positional relationship between the internal channel and the light spot; the nitrogen generator conveys the manufactured nitrogen to the cladding area through the internal channel of the cladding nozzle, and is also coaxial with the cladding material through the internal channel to ensure the accurate coupling of light, wire, and gas, prevent the formed part from oxidation, and protect the internal lens of the cladding nozzle; the water cooling device mainly conveys cooling water to the laser and the internal lens of the cladding nozzle to ensure the timely cooling of the optical lens and prevent damage.

[0012] In the system of the present invention, three material pipes (powder or wire), three beams (light spots), and the nozzle (powder or wire) are arranged coaxially, ensuring uniform heat when the wire or powder melts, which helps to improve the metallurgical bonding between the cladding layer and the substrate, as well as improve the surface quality of the cladding layer and obtain a smaller dilution rate.

[0013] The middle channel of the nozzle can convey powder or wire, and the three peripheral channels convey powder or wire, which can realize the simultaneous conveyance of wire and powder to the molten pool, achieve the full fusion of light, wire, and powder, improve the metallurgical bonding, and realize the formation of a high-quality cladding layer; and by changing the material type and the mass ratio of material conveyance, multiple materials can be melted simultaneously to form a high-performance cladding layer.

[0014] In the negative defocus state of the three-beam wire-powder hybrid laser cladding nozzle of the present invention, the outer diameter of the light spot is much larger than the diameter of the cladding material (wire / powder mixture), and the requirement for the position accuracy of the transmission of the wire / powder mixture during the laser cladding process is relatively low. At the same time, in the negative defocus state, the laser energy acting on the wire / powder mixture is more reasonably distributed compared to the focus and positive defocus states, avoiding the highly concentrated laser energy. Therefore, it is easier to obtain a higher-quality cladding layer in the negative defocus state. Brief Description of the Drawings

[0015] Figure 1 This is the system architecture diagram of the three-beam wire-powder hybrid laser cladding system of the present invention.

[0016] Figures 2(a)-(b) are the schematic structural diagrams of the three-beam wire-powder hybrid laser cladding nozzle of the present invention; among them, Figure 2(a) is the assembly diagram; Figure 2(b) is the exploded view.

[0017] Figures 3(a)-(c) are the schematic diagrams of different defocus amounts defined by the present invention; among them, Figure 3(a) is the schematic diagram under negative defocus, Figure 3(b) is the schematic diagram under the focus condition, and Figure 3(c) is the schematic diagram under positive defocus.

[0018] Figures 4(a)-(c) are the schematic diagrams of the relationship between the light spot and the cladding material; among them, Figure 4(a) is a schematic diagram of one relationship between the light spot and the cladding material under negative defocus, Figure 4(b) is a schematic diagram of another relationship between the light spot and the cladding material under negative defocus, and Figure 4(c) is the schematic diagram of the relationship between the light spot and the cladding material under the focus or positive defocus condition. Detailed Embodiments

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention; the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. In addition, unless otherwise clearly defined and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] Refer to Figure 1As shown in the figure, a three-beam wire and powder hybrid laser cladding system includes a workbench 9 for placing a workpiece 10, and is characterized in that: above the workbench 10 is a three-beam wire and powder hybrid laser cladding nozzle 11, and it also includes a controller 12, a robot 13, a laser 14, a water cooling device 15, a first cladding material conveying device 16, a nitrogen generator 17 and a second cladding material conveying device 18; the controller 12 is connected to the robot 13, the laser 14, the water cooling device 15, the first cladding material conveying device 16, the nitrogen generator 17 and the second cladding material conveying device 18, and is used to control the operation of each device; the robot 13 is connected to the three-beam wire and powder hybrid laser cladding nozzle 11 to control its movement trajectory and realize movement in the X-axis, Y-axis and Z-axis spaces; the laser 14 emits a laser beam, and the incident laser beam 201 is converted into three beams 202 by the three-beam wire and powder hybrid laser cladding nozzle 11 and projected onto the workpiece 10; the first cladding material conveying device 16 conveys the first cladding material 101 to the three-beam wire and powder hybrid laser cladding nozzle 11 and conveys it to the workpiece 10 through the three-beam wire and powder hybrid laser cladding nozzle 11; the second cladding material conveying device 18 conveys the second cladding material 102 to the three-beam wire and powder hybrid laser cladding nozzle 11 and conveys it to the workpiece 10 through the three-beam wire and powder hybrid laser cladding nozzle 11; the three-beam wire and powder hybrid laser cladding nozzle 11 focuses the three beams 202 on the workpiece 10 to form a cladding area 103, and at the same time conveys the first cladding material 101 and the second cladding material 102 to the cladding area 104; the water cooling device 15 conveys cooling water to the laser 14 and the three-beam wire and powder hybrid laser cladding nozzle 11; the nitrogen generator 17 conveys the manufactured nitrogen to the cladding area 104 through the three-beam wire and powder hybrid laser cladding nozzle 11.

[0022] As shown in FIGS. 2(a) and 2(b), the three-beam wire and powder hybrid laser cladding nozzle 11 includes a support frame 1. Above the support frame 1, there is a triangular prism 2 and three focusing lenses 3. The three focusing lenses 3 are arranged circumferentially on the three projection light paths of the triangular prism 2. On the support frame 1, a reflected light through-hole 103 is opened below the focusing lenses 3. The incident laser beam 201 is reflected into three beams 202 by the triangular prism 2 and the three focusing lenses 3 and projected and focused onto the workpiece 10 through the reflected light through-hole 103. A nozzle 4 for conveying the first cladding material 101 is fixed below the support frame 1. Below the nozzle 4, a material channel connection bracket 5 is installed. At the central position of the material channel connection bracket 5, there is a nozzle channel 502. The nozzle 4 is arranged in the nozzle channel 502. Around the nozzle channel 502, there are three material pipes 6 for conveying the second cladding material 102. The material pipes 6 are fixed in the material channel connection bracket 5. On the material channel connection bracket 5, there are also three reflected light channels 503. The three reflected light channels 503 are arranged in sequence between every two of the three material pipes 6. The three beams are respectively projected and focused onto the workpiece 10 through the corresponding reflected light channels 503; the nozzle 4 and the three material pipes 6 are coaxially arranged with the three beams 202.

[0023] Further, the material channel connection bracket 5 is detachably connected to the nozzle 4.

[0024] Further, a cavity is provided inside the material channel connection bracket 5. The cavity is connected to the water cooling device 15 through the inlet and outlet ports 501, 501'. Example 1:

[0025] The first cladding material 101 is powder or wire; the second cladding material 102 is powder. Example 2:

[0026] The first cladding material 101 is powder or wire; the second cladding material 102 is wire. Example 3:

[0027] The first cladding material 101 is powder or wire; the second cladding material 102 is powder or wire.

[0028] Further, the second cladding materials 102 conveyed in the three material pipes 6 can be the same or different. Example 4:

[0029] In this embodiment, the laser 14 is an IPG YLS-2000-TR fiber laser, the robot 13 is a KR 60HA type KUKA industrial robot, and the first cladding material conveying device 16 is a Miller S-74S type industrial wire feeder.

[0030] The system of this embodiment realizes "three-beam in-situ coaxial feeding of cladding materials". The coupling relationship between the laser cladding forming light and the cladding material is mainly determined by the coaxiality of the light and the cladding material, the axial relative position of the cladding layer or the workpiece and the light spot, and the radial size of the light spot and the wire / powder mixture material. It is known from research that the wire guiding or powder nozzle in the cladding head is coaxially designed with the three beams respectively. The manufacturing error and assembly error between the three beams and the feeding channel can be compensated by adjusting the angle of the focusing mirror and the position of the feeding channel (cladding material), so as to ensure that the spatial positions of the three beams and the cladding material are in a coaxial relationship.

[0031] Further, as shown in FIGS. 3(a)-(c), in this embodiment, the defocus amount is defined as the distance between the focus of the three beams and the workpiece surface in the vertical direction. When the focus is located on the workpiece surface, the defocus amount is defined as zero, as shown in FIG. 3(b); when the focus is located directly above the workpiece surface, it is defined as positive defocus, as shown in FIG. 3(c), and when the focus is located directly below the workpiece surface, it is defined as negative defocus, as shown in FIG. 3(a). The change of the defocus amount directly affects the change of the light spot size and energy distribution, and the light spot characteristics directly determine the matching relationship between the energy of the molten pool and the energy required for melting the cladding material. The coupling relationship between the light and the cladding material is discussed from the following three defocus amount position conditions:

[0032] Negative defocus condition

[0033] As shown in FIGS. 4(a)-(c), the area formed by the cladding material is located inside the circular area surrounded by the three light spots. According to the above definition, there are two states of the negative defocus light spot distribution: completely separated state, as shown in FIG. 4(a) and partially overlapping state as shown in FIG. 4(b). When the three light spots are in a completely separated state: the cladding material completely enters the lightless area surrounded by the three beams. When the temperature of the molten pool in this area does not reach the melting point of the cladding material, the cladding material cannot be melted and no cladding layer can be formed. When the temperature of the molten pool in this area is greater than the melting point of the cladding material, the cladding material melts and a cladding layer is formed. When the three light spots are in a partially overlapping state, the cladding material completely enters the overlapping area of the three beams. Compared with the separated state of the three beams, with the same input power and action time, the temperature of the overlapping area coaxial with the cladding material is higher than the temperature of the lightless area coaxial with the light spot in the separated state of the light spots, and it is easier to reach the temperature of the melting point of the cladding material. However, when its temperature does not reach the melting point of the cladding material, the cladding material still cannot be melted, and only when the temperature is greater than the melting point temperature of the cladding material can the cladding material be melted and a cladding layer be formed. However, if the temperature of the molten pool is too high, overburning will occur and a high-quality cladding layer cannot be formed.

[0034] Focus condition

[0035] The cladding material intersects coaxially with a single circular light spot. At the focal position, the three light spots completely overlap and form a single light spot, as shown in Fig. 4(c). Its cladding material also correspondingly converges at the center of the single light spot. The cladding material needs to pass through a certain distance from the nozzle to the molten pool. There will be a certain yaw during the transmission of the cladding material. Since the diameter of the light spot at the focal position is small, when the yaw amount of the cladding material exceeds the size of the light spot, it is easy to cause unstable melting of the cladding material and it is difficult to form a high-quality cladding layer. At the same time, due to the extremely high energy density at the focal position, which causes a large amount of energy in the molten pool, it will also cause overburning during the melting process of the cladding material or it is impossible to form a continuous, uniform and smooth cladding layer. Therefore, at the focal position, the tolerance ability is relatively weak, the process window is small, and the stability of the position accuracy is more sensitive than in the negative defocus state.

[0036] Positive defocus condition

[0037] The cladding material first passes through the focal position of the light spot and then enters the surface of the workpiece or the surface of the cladding layer. The light spot directly acts on the outer surface of the cladding material. Similarly, due to the small size of the light spot at the focal position, the position accuracy during the transmission of the cladding material is more sensitive than in the negative defocus position. Even a slight yaw of the cladding material will also exacerbate the insufficient coupling of light and the cladding material. The high-energy density laser beam at the focal point completely irradiates on the cladding material, usually exceeding the energy required for melting the cladding material, and it is easy to reach the melting point temperature of the cladding material or even cause overburning, and it is impossible to form a continuous high-quality cladding layer.

[0038] Based on the preliminary analysis of the above three coupling relationships between light and the cladding material, it can be seen that: in the negative defocus state, the outer diameter of the light spot is much larger than the diameter of the cladding material, and the requirement for the position accuracy of the transmission of the cladding material during laser cladding is relatively low. At the same time, in the negative defocus state, the laser energy acting on the cladding material is more reasonably distributed than in the focal and positive defocus states, avoiding the highly concentrated laser energy. Therefore, it is easier to obtain a higher-quality cladding layer in the negative defocus state. The above is mainly a preliminary analysis of the position and energy coupling of light and the cladding material. It is also necessary to establish a relationship model between the energy provided by the laser beam and the energy required for melting the wire / powder mixture to deeply analyze the coupling relationship between light and the cladding material.

[0039] Finally, it should be noted that: the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A three-beam wire and powder hybrid laser cladding system, comprising a workbench (9) for placing a workpiece (10), characterized in that: Above the workbench (9) is a three-beam wire and powder hybrid laser cladding nozzle (11), and it also includes a controller (12), a robot (13), a laser (14), a water cooling device (15), a first cladding material conveying device (16), a nitrogen generator (17) and a second cladding material conveying device (18); The controller (12) is connected to the robot (13), the laser (14), the water cooling device (15), the first cladding material conveying device (16), the nitrogen generator (17) and the second cladding material conveying device (18) for controlling the operation of each device; The robot (13) is connected to the three-beam wire and powder hybrid laser cladding nozzle (11) to control its movement trajectory and achieve movement in the X-axis, Y-axis and Z-axis spaces; The laser (14) emits a laser beam, and the incident laser beam (201) is converted into three beams (202) by the three-beam wire and powder hybrid laser cladding nozzle (11) and projected onto the workpiece (10); The first cladding material conveying device (16) conveys the first cladding material (101) to the three-beam wire and powder hybrid laser cladding nozzle (11) and conveys it to the workpiece (10) through the three-beam wire and powder hybrid laser cladding nozzle (11); The second cladding material conveying device (18) conveys the second cladding material (102) to the three-beam wire and powder hybrid laser cladding nozzle (11) and conveys it to the workpiece (10) through the three-beam wire and powder hybrid laser cladding nozzle (11); The three-beam wire and powder hybrid laser cladding nozzle (11) focuses the three beams (202) on the workpiece (10) to form a cladding area, and at the same time conveys the first cladding material (101) and the second cladding material (102) to the cladding area; The water cooling device (15) conveys cooling water to the laser (14) and the three-beam wire and powder hybrid laser cladding nozzle (11); The nitrogen generator (17) conveys the manufactured nitrogen to the cladding area (104) through the three-beam wire and powder hybrid laser cladding nozzle (11); The three-beam wire and powder hybrid laser cladding nozzle (11) includes a support frame (1), above which a triangular prism (2) and three focusing lenses (3) are arranged. The three focusing lenses (3) are circumferentially arranged on the three projection light paths of the triangular prism (2). A reflected light through hole (103) is opened on the support frame (1) below the focusing lenses (3). The incident laser beam (201) is reflected into three beams (202) by the triangular prism (2) and the three focusing lenses (3) and projected and focused onto the workpiece (10) through the reflected light through hole (103). A nozzle (4) for conveying the first cladding material (101) is fixed below the support frame (1); A material channel connection bracket (5) is installed below the nozzle (4). A nozzle channel (502) is provided at the central position of the material channel connection bracket (5). The nozzle (4) is arranged in the nozzle channel (502). Three material pipes (6) for conveying the second cladding material (102) are arranged around the nozzle channel (502). The material pipes (6) are fixed in the material channel connection bracket (5). Three reflection light channels (503) are also provided on the material channel connection bracket (5). The three reflection light channels (503) are sequentially arranged between every two of the three material pipes (6). The three beams are respectively projected and focused onto the workpiece (10) through the corresponding reflection light channels (503); the nozzle (4) and the three material pipes (6) are coaxially arranged with the three beams (202); The material channel connection bracket (5) is detachably connected to the nozzle (4); The three beams (202) are projected onto the workpiece (10) to form three independent light spots (105). The circumcircle (106) of the three light spots (105) can envelope the area where the first cladding material (101) and the second cladding material (102) are located, and the first cladding material (101) and the second cladding material (102) are located outside the three independent light spots (105); A cavity is provided inside the material channel connection bracket (5). The cavity is connected to the water cooling device (15) through the inlet and outlet ports (501, 501'); 2. The three-beam wire powder hybrid laser cladding system according to claim 1, wherein: The first cladding material (101) is powder or wire; 3. The three-beam wire powder hybrid laser cladding system according to claim 1, characterized in that: The second cladding material (102) is powder or wire; 4. The three-beam wire powder hybrid laser cladding system according to claim 1, characterized in that: The second cladding materials (102) conveyed in the three material pipes (6) are the same or different.

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