Coaxial fuse laser additive device and method based on light spot shape control

Abstract

The invention belongs to the technical field of laser additive manufacturing, and discloses a coaxial fuse laser additive manufacturing device and method based on light spot shape control. The device comprises a light splitting mechanism, a light spot shaping mechanism, a light beam focusing mechanism and the like. The light splitting mechanism is used for splitting a single laser beam into three beams, and light spot brightness uniformization is promoted. A supporting table is arranged in the light spot shaping mechanism, and a driving motor is arranged on the upper portion of the supporting table and drives the rotatable reflecting mirror to rotate at a high speed. During material adding operation, laser beams are shot into the three groups of light spot forming mirror surface walls through the rotatable reflecting mirrors after being split, and different light spots are formed under the reflection constraint of the mirror surface walls. All the lens sets, the motor, the supporting part and the like are hollow, a welding wire penetrates into the hollow area, and light-wire coaxiality is achieved. According to the invention, the three groups of light spot forming mirror surface walls are used for controlling the shape of the light spot, the setting of the hollow area can ensure that the welding wire does not shield the laser beam, and finally, the coaxial fuse wire additive material technology with adjustable and controllable light spots is realized.

Description

Technical Field

[0001] The invention relates to the technical field of laser material addition, and discloses a coaxial fuse laser material addition device and method based on spot shape control. Background Art

[0002] Coaxial laser additive manufacturing is an additive manufacturing technology that melts metal powder with a laser and precisely deposits it through a protective gas nozzle. Its main advantage is that it can achieve a high-precision and high-efficiency 3D printing process, which is suitable for the manufacture of complex shapes and high-performance components. Through the coaxial design, the laser beam and the protective gas work together in the same axial direction to protect the molten pool from oxidation and optimize the deposition process of the material, thereby improving the mechanical properties and surface quality of the component. At the same time, the laser can accurately control the heat input and reduce the heat-affected zone, thereby reducing the internal stress and deformation risk of the material, which is particularly suitable for the manufacture of high-performance alloys and precision structural parts. This technology also has a high material utilization rate and low waste, and can accurately deposit the required materials, reducing material consumption and costs. Due to its strong adaptability, it can be widely used in aerospace, medical, automotive and other fields, especially in the manufacture of complex geometries, heterogeneous material combinations and customized production. In summary, coaxial laser additive manufacturing not only provides high-quality and efficient manufacturing solutions, but also promotes the personalization and small-batch production of high-performance components, becoming an important development direction in the field of additive manufacturing.

[0003] On the other hand, the change of laser spot shape is of great significance for laser additive and other laser processing applications. By adjusting the spot shape, it is possible to control heat input, improve additive efficiency, reduce deformation, improve the microstructure of additive parts, and even adapt to the additive needs of different materials and structures. This makes laser processing more flexible, and it is possible to select spots of different shapes and sizes according to actual needs to meet the high requirements of precision, efficiency and quality in modern industry. However, due to the limitations of the optical path principle, the commonly used spots for laser additive are mostly ring-shaped, and it is difficult to integrate laser spots of various shapes into the same laser head. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a coaxial fuse laser additive device and method based on spot control. The device includes components such as a splitter mechanism, a spot shaping mechanism, and a beam focusing mechanism. The splitter mechanism has the function of dividing the light beam into three. The spot shaping mechanism has a built-in support platform. A driving motor is provided on the upper part of the support platform. The driving motor drives the rotatable reflector to rotate at high speed, and the laser beam can be reflected into three groups of spot forming mirror walls. The spot forming mirror wall group includes three types of mirrors: annular, triangular and square. The mirror wall group is adjusted by the nut of the moving mechanism to achieve vertical up and down movement. Through the matching relationship between the mirror wall and the laser beam, the operator controls the laser beam to be shot into different mirror walls to achieve different spot control shapes. The beam focusing mechanism converges the shaped laser beam to achieve additive operation. In the central area of ​​the present invention, all mirror groups, motors, support parts, etc. are set to be hollow, and the hollow area is used for welding wire to pass through to achieve coaxial fuse.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A coaxial fused wire laser additive device and method based on spot shape control, characterized in that it includes five main systems: a light splitting mechanism, a light spot shaping mechanism, a beam focusing mechanism, a shielding gas delivery mechanism, and a welding wire delivery mechanism.

[0007] Furthermore, the light splitting mechanism comprises a plurality of components including a collimating lens, a light splitting lens group, a conductive head, a conductive slot, etc. The light splitting mechanism comprises a light splitting prism, a reflector, a connecting slot, a welding wire slot, etc.

[0008] Furthermore, the light spot shaping mechanism comprises a moving mechanism, an annular mirror wall, a triangular mirror wall, a square mirror wall, a fixed wire feeding shaft, a rotatable reflector, a driving motor, a support platform, a plane mirror (29) and other components.

[0009] Furthermore, the light beam focusing mechanism (3) comprises a focusing mirror (31), a plane mirror (32) and other components.

[0010] Furthermore, the beam splitter prism is fixed at the center of the support plate, and can divide the high-energy laser beam into three laser beams with uniform energy and an angle of 120° and shoot them horizontally into the reflector. The reflector is fixed at the groove of the support plate, and the reflection angle is fixed, and the laser beam can be reflected into the rotatable reflector through the hollow part at the groove. The connecting groove is connected to the wall of the laser head, and there is a scale on the outer surface of the movable groove to facilitate fixing the position of the connecting groove and ensure that the three connecting grooves can be in the same plane without tilting. The welding wire groove is used to fill in the welding wire. The conductive head is externally connected to a power supply, and a wire is wound on its upper part. The conductive groove is used for internal wires to realize power supply to the drive motor.

[0011] Furthermore, the driving motor has a rotation speed of 200r / s, and the surface of the rotatable reflector is a non-uniform mirror group, which can change the direction of the laser beam during the rotation process. It is fixedly connected to the driving motor and can realize synchronous high-speed rotation, and evenly reflect the three laser beams into the spot-forming mirror wall group.

[0012] Furthermore, the light spot forming mirror wall group includes the annular mirror wall, the triangular mirror wall and the square mirror wall, and the mirror wall group has a reflector inside, which can reflect the light to the plane mirror as losslessly as possible. Due to the different shapes of the mirror wall groups, the laser beam shaping function can be achieved.

[0013] Furthermore, the three groups of mirror walls are fixedly connected and will not move relative to each other. At the same time, the annular mirror wall is actively connected to the moving mechanism, and the mirror wall group can be translated up and down by tightening and moving the nut up and down, so that the coaxial laser beam can be injected into different mirror walls, and finally the shape of the light spot can be adjusted. At the same time, there are scales on the outer surface of the moving mechanism, which can ensure that the mirror wall group always remains horizontal without tilting.

[0014] Furthermore, the outer shaft wall of the fixed wire feeding shaft is fixedly connected to the support platform, and the inner hollow part serves as a wire guide shaft. The diameter of the wire guide shaft is slightly larger than the diameter of the welding wire, and the welding wire can be coaxially fed to the laser focus. The rotatable reflector is fixed to the drive motor and can achieve high-speed rotation under the drive of the drive motor; the surface of the rotatable reflector is smooth and bright, which can minimize the loss of laser energy. The inner diameter of the rotatable reflector is hollow, serving as a guide shaft pipe. The diameter of the guide shaft pipe is slightly larger than that of the fixed wire feeding shaft. The existing annular hollow area is an annular conductive groove that can be used for the placement of the energized wire, which can not only ensure that the wire will not block the laser, but also prevent the wire from being entangled due to the high-speed rotation of the rotatable reflector.

[0015] Furthermore, the protective gas delivery mechanism (4) is externally connected to a protective gas cylinder, so that an oxygen-free environment can be achieved during the material addition process.

[0016] Furthermore, the welding wire feeding mechanism is located in the center area of ​​the entire device, and the center positions of the components in the center area of ​​the device are hollowed out to realize the coaxial feeding of the welding wire. At the same time, since the welding wire is inserted from the center position, it can be ensured that the introduction of the welding wire will not block the laser beam, thereby affecting the formation of the light spot.

[0017] Furthermore, the preset convergence focus of the laser is located 10 to 50 mm directly below the bottom of the laser head. The preset convergence focus can achieve a matching relationship between light and wire.

[0018] Furthermore, a coaxial fuse laser additive method based on spot shape control specifically includes the following steps:

[0019] Step 1: The fiber laser emits coaxial low-temperature cold light to replace the coaxial high-energy laser beam in the actual additive process. Turn on the drive motor to rotate and reflect the low-temperature cold light and finally form an initial light spot. According to the actual additive light spot requirements, the operator adjusts the nut of the moving mechanism to move the mirror wall group vertically up and down, and can choose to align the annular mirror wall, the triangular mirror wall and the square mirror wall to obtain a light spot shape and size that meets the additive requirements.

[0020] Step 2: Open the valve of the protective gas cylinder to allow the protective gas to be delivered to the surface of the additive area through the protective gas delivery mechanism to ensure that there is no oxygen in the entire additive process.

[0021] Step three, adjust the fiber laser, stop emitting low-temperature cold light and instead emit a coaxial high-energy laser beam. After the coaxial laser beam is split by the beam splitting prism, it is reflected by the reflector to the rotatable reflector. The drive motor drives the rotatable reflector to rotate at high speed, continuously reflecting the laser beam with itself as the center of the circle to the surrounding light spot forming mirror wall group. Finally, after being shaped, the coaxial light beam converges at a preset focus through the focusing mirror and the plane mirror.

[0022] Step 4: The welding wire feeding mechanism simultaneously fills the additive material into the additive area to complete the additive operation.

[0023] The advantages and benefits of the present invention are as follows:

[0024] The present invention provides a coaxial fuse laser additive device and method based on spot control, the device includes components such as a light splitting mechanism, a light spot shaping mechanism, a beam focusing mechanism, a shielding gas conveying mechanism, and a welding wire conveying mechanism. The light splitting mechanism is used to split a single laser beam into three beams to promote uniform brightness of the light spot. The light spot shaping mechanism has a built-in support platform, and a driving motor is provided on the upper part of the support platform, and the driving motor drives a rotatable reflector to rotate at high speed. During the additive operation, the laser beam is shot into three groups of light spot forming mirror walls through a rotatable reflector after light splitting, and different light spots are formed under the reflection constraint of the mirror wall. The mirror wall group is connected to the moving mechanism, and the matching between the wall group with different light spot morphologies and the laser beam is achieved by tightening and loosening the nut and moving it up and down. On the other hand, all mirror groups, motors, support parts, etc. of the present invention are set to be hollow, and the hollow area is for the welding wire to pass through to achieve light-wire coaxiality. In the present invention, three groups of spot-forming mirror walls are used to control the spot shape, and the setting of the hollow area can ensure that the welding wire will not block the laser beam, and finally realize the coaxial fused wire additive technology with adjustable spot. The present invention is based on the optical path principle of rotating laser, and controls the spot shape by vertically translating the mirror wall group up and down, which has a wide range of application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1It is a cross-sectional schematic diagram of a coaxial fused laser additive device based on beam shaping;

[0026] Figure 2 It is a three-dimensional schematic diagram of the light splitting mechanism;

[0027] Figure 3 It is the cross-section and sectional view of three groups of light spot forming mirror wall;

[0028] Figure 4 It is a cross-sectional and sectional view of the fixed wire feed shaft and the rotatable reflector;

[0029] Figure 5 It is a schematic diagram of the additive process of a coaxial fused laser additive device based on beam shaping.

[0030] 1-Spectral splitting mechanism: 11 collimating lens; 12 spectroscope group; 121 spectroscopic prism; 122 reflecting mirror; 123 connecting slot; 124 welding wire slot; 13 conductive head; 14 conductive slot

[0031] 2- Spot shaping mechanism: 21 moving mechanism; 22 annular mirror wall; 23 triangular mirror wall; 24 square mirror wall; 25 fixed wire feeding shaft; 251 wire guide shaft; 252 external shaft wall; 26 rotatable reflector; 261 rotatable reflector surface; 262 guide shaft pipeline; 263 annular conductive groove; 27 driving motor; 28 support platform; 29 plane mirror

[0032] 3- Beam focusing mechanism: 31 focusing mirror; 32 plane mirror

[0033] 4-Protective gas delivery mechanism

[0034] 5-Wire feeding mechanism DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific implementation cases described herein are only used to explain the present invention, rather than to limit the present invention. It is also necessary to explain that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0036] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" 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 a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0038] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0039] The present invention is further described below through several specific embodiments. In this example, in an aluminum alloy additive manufacturing experiment, the above-mentioned coaxial fuse laser additive device and method based on spot shape control is used to achieve the control of the spot shape.

[0040] like Figure 1 As shown, a coaxial fused laser additive device based on spot shaping includes five main systems: a beam splitting mechanism 1, a spot shaping mechanism 2, a beam focusing mechanism 3, a shielding gas delivery mechanism 4, and a welding wire delivery mechanism 5.

[0041] Preferably, the light splitting mechanism 1 includes a plurality of components such as a collimating lens 11 , a light splitting lens group 12 , a conductive head 13 , a conductive slot 14 and the like.

[0042] Preferably, the light spot shaping mechanism 2 includes a moving mechanism 21, an annular mirror wall 22, a triangular mirror wall 23, a square mirror wall 24, a fixed wire feeding shaft 25, a rotatable reflector 26, a driving motor 27, a support platform 28, a plane mirror 29 and other components.

[0043] Preferably, the beam focusing mechanism 3 includes components such as a focusing mirror 31 and a plane mirror 32 .

[0044] Preferably, if Figure 2 As shown, the light splitting mechanism 12 includes components such as a light splitting prism 121, a reflector 122, a connecting slot 123, and a welding wire slot 124.

[0045] Preferably, the beam splitter prism 121 is fixed at the center of the support plate, and can divide the high-energy laser beam into three laser beams with uniform energy and an angle of 120° and horizontally project them into the reflector 122. The reflector 122 is fixed at the groove of the support plate, and the reflection angle is fixed, and the laser beam can be reflected to the rotatable reflector 26 through the hollow part at the groove. The connecting groove 123 is connected to the wall of the laser head, and there is a scale on the outer surface of the movable groove, which is convenient for fixing the position of the connecting groove 123 and ensuring that the three connecting grooves 123 can be in the same plane without tilting. The welding wire groove 124 is used to realize the filling of welding wire. The conductive head 13 is externally connected to a power supply, and a wire is wound on its upper part. The conductive groove 14 is used for internal wires to realize the power supply of the drive motor 27.

[0046] Preferably, the rotation speed of the driving motor 27 is 200r / s, and the surface of the rotatable reflector 26 is a non-uniform mirror group, which can change the direction of the laser beam during the rotation process. It is fixedly connected to the driving motor 27, and can realize synchronous high-speed rotation, and evenly reflect the three laser beams into the spot forming mirror wall group.

[0047] Preferably, the light spot forming mirror wall group includes the annular mirror wall 22, the triangular mirror wall 23 and the square mirror wall 24. The mirror wall group has a reflector inside, which can reflect the light to the plane mirror 29 as losslessly as possible. Due to the different shapes of the mirror wall groups, the laser beam shaping function can be achieved.

[0048] Preferably, the three groups of mirror walls are fixedly connected and will not move relative to each other. At the same time, the annular mirror wall 22 is actively connected to the moving mechanism 21, and the mirror wall group can be translated up and down by tightening and moving the nut up and down, so that the coaxial laser beam can be injected into different mirror walls, and finally the shape of the light spot can be regulated. At the same time, there are scales on the outer surface of the moving mechanism 21, which can ensure that the mirror wall group always remains horizontal without tilting.

[0049] Preferably, the outer shaft wall 252 of the fixed wire feeding shaft 25 is fixedly connected to the support platform, and the inner hollow part serves as the wire guide shaft 251. The diameter of the wire guide shaft 251 is slightly larger than the diameter of the welding wire, and the welding wire can be coaxially fed to the laser focus. The rotatable reflector 26 is fixed to the drive motor 27 and can achieve high-speed rotation under the drive of the drive motor 27; the rotatable reflector surface 261 is smooth and bright, which can minimize the laser energy loss. The inner diameter of the rotatable reflector 26 is hollow, serving as a guide shaft pipe 262. The diameter of the guide shaft pipe 262 is slightly larger than the fixed wire feeding shaft 25. The annular hollow area is an annular conductive groove 263 that can be used for the placement of the energized wire, which can not only ensure that the wire will not block the laser, but also prevent the wire from being entangled due to the high-speed rotation of the rotatable reflector 26.

[0050] Preferably, the protective gas delivery mechanism 4 is externally connected to a protective gas cylinder to achieve an oxygen-free environment during the additive process.

[0051] Preferably, the welding wire feeding mechanism 5 is located in the central area of ​​the entire device, and the central positions of the components in the central area of ​​the device are hollowed out to achieve coaxial feeding of the welding wire. At the same time, since the welding wire is inserted from the central position, it can be ensured that the introduction of the welding wire will not block the laser beam, thereby affecting the formation of the light spot.

[0052] Preferably, the laser preset convergence focus is located 10 to 50 mm below the bottom of the laser head. The preset convergence focus can achieve a matching relationship between light and wire.

[0053] Preferably, a coaxial fuse laser additive method based on spot shape control specifically comprises the following steps:

[0054] Step 1: The fiber laser emits coaxial low-temperature cold light to replace the coaxial high-energy laser beam in the actual additive process. Turn on the drive motor 27 to rotate and reflect the low-temperature cold light and finally form an initial light spot. According to the requirements of the actual additive light spot, the operator adjusts the nut of the moving mechanism 21 to move the mirror wall group vertically up and down, and can choose to align the annular mirror wall 22, the triangular mirror wall 23 and the square mirror wall 24 to obtain a light spot shape and size that meets the additive requirements.

[0055] Step 2: Open the valve of the protective gas bottle to allow the protective gas to be delivered to the surface of the additive area through the protective gas delivery mechanism 4 to ensure that there is no oxygen in the entire additive process.

[0056] Step three, adjust the fiber laser, stop emitting low-temperature cold light and instead emit a coaxial high-energy laser beam. After the coaxial laser beam is split by the beam splitting prism 121, it is reflected by the reflector to the rotatable reflector 26. The drive motor 27 drives the rotatable reflector 26 to rotate at high speed, continuously reflecting the laser beam with itself as the center of the circle to the surrounding light spot forming mirror wall group. Finally, after being shaped, the coaxial light beam converges at a preset focus through the focusing mirror 31 and the plane mirror 32.

[0057] Step 4: The welding wire feeding mechanism 5 simultaneously fills the additive material into the additive area to complete the additive operation.

[0058] Preferably, if Figure 5As shown, through the above steps and methods, the present invention realizes the integration of annular, triangular and square light spots, and can select corresponding light spots according to different additive process requirements in the actual additive process. It is worth mentioning that the present invention is not limited to these three light spots. For the needs of light spots of other shapes, the present invention can achieve the selection of different light spots by installing mirror wall groups of different morphologies in the laser head.

[0059] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A coaxial fuse laser additive device and method based on spot shape control, characterized in that: The invention comprises five main systems: a light splitting mechanism (1), a light spot shaping mechanism (2), a light beam focusing mechanism (3), a shielding gas conveying mechanism (4), and a welding wire conveying mechanism (5). The light splitting mechanism (1) comprises a plurality of components including a collimating lens (11), a light splitting mirror group (12), a conductive head (13), a conductive slot (14), etc. The light splitting mechanism (12) comprises a light splitting prism (121), a reflector (122), a connecting slot (123), a welding wire slot (124), etc. The light spot shaping mechanism (2) comprises a moving mechanism (21), an annular mirror wall (22), a triangular mirror wall (23), a square mirror wall (24), a fixed wire feeding shaft (25), a rotatable reflector (26), a driving motor (27), a support platform (28), a plane mirror (29) and other components. The light beam focusing mechanism (3) comprises a focusing mirror (31), a plane mirror (32) and other components.

2. The coaxial fused laser additive device based on spot shape control according to claim 1 is characterized in that: The beam splitter prism (121) is fixed at the center of the support plate, and can split the high-energy laser beam into three laser beams with uniform energy and an angle of 120°, and horizontally project them into the reflector (122). The reflector (122) is fixed at the groove of the support plate, and the reflection angle is fixed, and the laser beam can be reflected into the rotatable reflector (26) through the hollow part at the groove. The connecting groove (123) is connected to the wall of the laser head, and there is a scale on the outer surface of the movable groove, which is convenient for fixing the position of the connecting groove (123) and ensuring that the three connecting grooves (123) can be in the same plane without tilting. The welding wire groove (124) is used to realize the filling of welding wire. The conductive head (13) is externally connected to a power supply, and a wire is wound on its upper part. The conductive groove (14) is used to internally hold a wire to realize the power supply of the drive motor (27).

3. The coaxial fused laser additive device based on spot shape control according to claim 1 is characterized in that: The driving motor (27) has a rotation speed of 200 r / s, and the surface of the rotatable reflector (26) is a non-uniform mirror group, which can change the direction of the laser beam during the rotation process. It is fixedly connected to the driving motor (27) and can realize synchronous high-speed rotation, and evenly reflect the three laser beams into the spot-forming mirror wall group.

4. The coaxial fused laser additive device based on spot shape control according to claim 3 is characterized in that: The light spot forming mirror wall group comprises the annular mirror wall (22), the triangular mirror wall (23) and the square mirror wall (24), and the mirror wall group has a reflector inside, which can reflect the light to the plane mirror (29) as losslessly as possible. Due to the different shapes of the mirror wall groups, the shaping function of the laser beam can be realized.

5. The coaxial fused laser additive device based on spot shape control according to claim 4 is characterized in that: The three groups of mirror walls are fixedly connected and will not move relative to each other. At the same time, the annular mirror wall (22) is actively connected to the moving mechanism (21), and the mirror wall group can be translated up and down by tightening and moving the nut up and down, so that the coaxial laser beam can be injected into different mirror walls, and finally the shape of the light spot can be regulated. At the same time, there are scales on the outer surface of the moving mechanism (21), which can ensure that the mirror wall group always remains horizontal without tilting.

6. The coaxial fused laser additive device based on spot shape control according to claim 1, characterized in that: The outer shaft wall (252) of the fixed wire feeding shaft (25) is fixedly connected to the support platform, and the inner hollow part serves as the wire guide shaft (251). The diameter of the wire guide shaft (251) is slightly larger than the diameter of the welding wire, and the welding wire can be coaxially fed to the laser focus. The rotatable reflector (26) is fixed to the driving motor (27) and can achieve high-speed rotation under the drive of the driving motor (27); the rotatable reflector surface (261) is smooth and bright, and the laser energy loss can be reduced as much as possible. The inner diameter of the rotatable reflector (26) is hollow, serving as a guide shaft pipe (262). The diameter of the guide shaft pipe (262) is slightly larger than that of the fixed wire feeding shaft (25). The annular hollow area is an annular conductive groove (263) that can be used to place the energized wire, which can ensure that the wire will not block the laser and prevent the wire from being entangled due to the high-speed rotation of the rotatable reflector (26).

7. The coaxial fused laser additive device based on spot shape control according to claim 1, characterized in that: The protective gas delivery mechanism (4) is externally connected to a protective gas cylinder, so as to achieve an oxygen-free environment during the material addition process.

8. The coaxial fused laser additive device based on spot shape control according to claim 1 is characterized in that: The welding wire conveying mechanism (5) is located in the central area of ​​the entire device, and the central positions of the components in the central area of ​​the device are hollowed out to realize the coaxial conveying of the welding wire. At the same time, since the welding wire is inserted from the central position, it can be ensured that the introduction of the welding wire will not block the laser beam, thereby affecting the formation of the light spot.

9. The coaxial fused laser additive device based on spot shape control according to claim 1, characterized in that: The preset laser focus is located 10 to 50 mm below the bottom of the laser head. The preset focus can achieve the matching relationship between light and wire.

10. The coaxial fused laser additive method based on spot shape control according to claim 1, characterized in that: The specific steps include: Step 1: The fiber laser emits coaxial low-temperature cold light to replace the coaxial high-energy laser beam in the actual material addition process. The drive motor (27) is turned on to rotate and reflect the low-temperature cold light and finally form an initial light spot. According to the actual requirements for the additive light spot, the operator adjusts the nut of the moving mechanism (21) to move the mirror wall group vertically up and down, and can select the annular mirror wall (22), the triangular mirror wall (23) and the square mirror wall (24) to be aligned to obtain a light spot shape and size that meets the additive requirements. Step 2: Open the valve of the protective gas bottle to allow the protective gas to be transported to the surface of the material adding area through the protective gas transport mechanism (4), thereby ensuring that the entire material adding process is oxygen-free. Step three, adjust the fiber laser, stop emitting low-temperature cold light and instead emit a coaxial high-energy laser beam. After the coaxial laser beam is split by the beam splitting prism (121), it is reflected by the reflector to the rotatable reflector (26). The drive motor (27) drives the rotatable reflector (26) to rotate at a high speed, and continuously reflects the laser beam with itself as the center of the circle to the surrounding light spot forming mirror wall group. Finally, after being shaped, the coaxial light beam is converged at a preset focus through the focusing mirror (31) and the plane mirror (32). Step 4: The welding wire feeding mechanism (5) simultaneously fills the additive material into the additive area to complete the additive operation.

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