Fiber-coupled adjustable focus laser cutting device

Abstract

The application relates to a fiber-coupled adjustable-focus laser cutting device, which comprises a laser transmitter for transmitting laser through an input optical fiber; a laser receiving module comprising a mounting seat, an optical fiber base, a transmission mechanism and a focusing mechanism, the focusing mechanism drives the optical fiber base to move along the axial direction through the transmission mechanism, and motor-free focusing in a nuclear radiation environment is realized; a laser transmission module comprising a parabolic mirror for collimating and focusing laser; and a laser output module for outputting a laser beam to a workpiece to be cut. The device converts the focusing technology depending on a motor in the prior art into a full-mechanical transmission focusing design, avoids the failure risk of motors and other electronic elements in a radiation environment, and realizes high-precision and high-reliability focusing functions through the cooperation of the focusing mechanism, the transmission mechanism and the limiting pin, so that the laser cutting device has good radiation resistance, high long-term operation stability and long service life in a nuclear radiation environment.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and more specifically, to a fiber-coupled adjustable focus laser cutting device. Background Technology

[0002] Spent fuel rods (or irradiated nuclear fuel) are consumed nuclear fuel discharged after a nuclear reactor has been operational. Although most of their energy has been released through fission reactions, they remain highly radioactive and contain recyclable nuclides. Therefore, developing efficient and safe spent fuel rod reprocessing technologies is crucial for this field.

[0003] Laser cutting, as a non-contact processing method, has promising applications in the nuclear industry. However, conventional laser cutting heads still present some problems in nuclear radiation environments. For example, the focusing motor is prone to failure in such environments. The main reasons include: the circuit boards, sensors, and insulation materials inside the motor undergo ionization damage under strong radiation, leading to decreased insulation performance, short circuits, or signal distortion. Radiation can also cause the magnetic properties of permanent magnets to decay, affecting the motor's torque and accuracy. Furthermore, radiation accelerates the decomposition of lubricant in the motor bearings, leading to increased mechanical wear and affecting motor performance. Ultimately, this results in decreased stability and a shorter lifespan for the laser cutting device.

[0004] Therefore, there is a need in this field to develop laser cutting devices with higher stability and longer lifespan. Summary of the Invention

[0005] In view of this, and to address the above problems, the present invention provides a fiber-coupled adjustable focus laser cutting device, which greatly improves the long-term operational stability of the laser cutting device and extends its service life.

[0006] To achieve the above objectives, the present invention provides a fiber-coupled adjustable-focus laser cutting device, comprising: a laser emitter for emitting a laser beam and transmitting the laser beam downstream of the optical path via an input optical fiber; and a laser receiving module located downstream of the laser emitter, for connecting to the input optical fiber and adjusting the position of the output end of the input optical fiber relative to the laser transmission module. The laser receiving module includes a mounting base, an optical fiber base, a transmission mechanism, and a focusing mechanism. The mounting base includes a receiving cavity. A first end of the optical fiber base is fixedly connected to the input optical fiber, and a second end of the optical fiber base is connected to the transmission mechanism within the receiving cavity. One end of the focusing mechanism extends outside the receiving cavity to form an operating end, and the other end is connected to the transmission mechanism within the receiving cavity. At least one limiting pin is provided through the side wall of the receiving cavity. The limiting pin passes through the side wall of the receiving cavity and is inserted into the side wall of the fiber optic base. The insertion depth of the limiting pin is 30% to 50% of the wall thickness of the fiber optic base. When the focusing mechanism is operated, the focusing mechanism drives the transmission mechanism to move, and then the transmission mechanism drives the fiber optic base to move axially. The fiber optic base and the transmission mechanism are provided with a coaxial hollow channel. The laser transmitted by the input fiber is transmitted downstream of the optical path through the hollow channel. The laser transmission module is located downstream of the laser receiving module and is used to collimate and focus the laser beam and transmit the laser beam downstream of the optical path. The laser output module is located downstream of the optical path of the laser transmission module and is used to output the laser beam to the workpiece to be cut.

[0007] In one specific embodiment, the transmission mechanism includes a rotating sleeve, a vertical bevel gear, and a horizontal bevel gear. The focusing mechanism is a rotatable focusing handle. One end of the focusing handle is coaxially connected to the vertical bevel gear in the receiving cavity. The horizontal bevel gear is coaxially fixedly connected to the bottom of the rotating sleeve. The vertical bevel gear meshes with the horizontal bevel gear. The second end of the optical fiber base is threadedly connected to the rotating sleeve in the receiving cavity. The optical fiber base and the rotating sleeve are provided with coaxial hollow channels.

[0008] In one specific embodiment, the operating end of the focusing mechanism is provided with a handle for the robotic arm to grip.

[0009] In one specific embodiment, the laser transmission module includes a mounting cavity, which includes a first laser transmission channel and a second laser transmission channel. The first laser transmission channel is coaxially connected to the hollow channel of the rotating sleeve. A first parabolic reflector and a second parabolic reflector are fixedly installed inside the mounting cavity. After the laser beam is transmitted from the first laser transmission channel, it is collimated by the first parabolic reflector to form a parallel laser beam, and then focused by the second parabolic reflector to form a focused beam. The second laser transmission channel is connected to the laser output module, and the collimated and focused laser beam is transmitted downstream of the optical path through the second laser transmission channel.

[0010] In one specific embodiment, an integrated module is also included. The integrated module includes a base on which first to eighth connectors and a locking head are disposed. The first connector is connected in parallel to the coolant inlets of the first and second parabolic reflectors via pipelines. The second connector is connected in parallel to the coolant outlets of the first and second parabolic reflectors via pipelines. One end of the fifth connector is connected to the coolant, and the other end is connected to the first connector through a first through hole inside the base. One end of the seventh connector is connected to a coolant recovery device, and the other end is connected to the second connector through a second through hole inside the base. The third connector is connected to the laser output module via a pipeline. One end of the sixth connector is connected to a compressed air supply device, and the other end is connected to the third connector through a third through hole inside the base. The fourth connector is connected sequentially between the first and second parabolic reflectors via pipelines and through holes inside the mounting cavity. One end of the eighth connector is connected to a protective gas source, and the other end is connected to the fourth connector through a fourth through hole inside the base. One side of the integrated module is connected to the laser transmission module, and the other side is connected to the machine tool via the locking head.

[0011] In one specific embodiment, the mirror substrates of the first parabolic reflector and the second parabolic reflector are made of oxygen-free copper.

[0012] In one specific embodiment, the mounting cavity is made of stainless steel or lead.

[0013] In one specific embodiment, the first parabolic reflector and / or the second parabolic reflector are provided with a cooling cavity. The coolant inlet and coolant outlet pass through the side wall of the mounting cavity and communicate with the cooling cavity inside the first parabolic reflector and / or the second parabolic reflector. The cooling cavity is provided with N flow-guiding heat dissipation fins, where N is greater than or equal to 2. Each flow-guiding heat dissipation fin extends from the coolant inlet end to the coolant outlet end, and a coolant flow channel is formed between two adjacent flow-guiding heat dissipation fins.

[0014] In one specific embodiment, the heat dissipation fins have an inclination angle of 15°±2° along the direction of coolant flow, and the height of each heat dissipation fin is in the ratio of the width of the cooling cavity to 1:4-1:1.5.

[0015] In one specific embodiment, the heat dissipation fins employ a gradient porous structure, with the porosity of the heat dissipation fins gradually changing from 35% on the coolant inlet side to 15% on the coolant outlet side along the coolant flow direction.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The fiber-coupled adjustable focus laser cutting device provided by the present invention transforms the existing motor-dependent focusing technology into a fully mechanical transmission focusing design, avoiding the failure risk of electronic components such as motors in the radiation environment. Through the coordinated cooperation of the focusing mechanism, transmission mechanism and limit pin, a high-precision and high-reliability focusing function is achieved, realizing a laser cutting device with good radiation resistance, high long-term operational stability and long life in the nuclear radiation environment. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of a fiber-coupled adjustable focus laser cutting device according to the present invention.

[0018] Figure 2 This is a cross-sectional structural diagram of the laser receiving module in this invention.

[0019] Figure 3 This is a schematic diagram of the laser transmission module in this invention.

[0020] Figure 4 This is a cross-sectional structural diagram of a fiber-coupled adjustable focus laser cutting device according to the present invention.

[0021] Figure 5 This is a schematic diagram of the structure of the first parabolic reflector or the second parabolic reflector in this invention.

[0022] Figure 6 This is a schematic diagram of the cooling cavity structure of the first parabolic reflector or the second parabolic reflector in this invention.

[0023] Figure 7 This is a schematic diagram of the tilt angle and gradient porous structure of the heat dissipation fins along the flow direction of the cooling liquid in this invention.

[0024] Figure 8 This is a schematic diagram of the integrated module structure in this invention.

[0025] Figure 9 This is a schematic diagram of the structure of a fiber-coupled adjustable focus laser cutting device after it is connected to a machine tool according to the present invention. Detailed Implementation

[0026] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0028] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] In one specific implementation, such as Figures 1-2As shown, a fiber-coupled adjustable-focus laser cutting device is provided, comprising: a laser emitter (not shown): for emitting a laser beam and transmitting the laser beam downstream of the optical path through an input optical fiber (not shown); a laser receiving module 1: located downstream of the laser emitter's optical path, for connecting to the input optical fiber and adjusting the position of the output end of the input optical fiber relative to the laser transmission module 2. The laser receiving module 1 includes a mounting base 10, an optical fiber base 101, a transmission mechanism 100, and a focusing mechanism 105. The mounting base 10 includes a receiving cavity. The first end of the optical fiber base 101 is fixedly connected to the input optical fiber, and the second end of the optical fiber base is connected to the transmission mechanism 100 in the receiving cavity. One end of the focusing mechanism 105 extends out of the receiving cavity to form an operating end, and the other end is connected to the transmission mechanism 100 in the receiving cavity. At least one limiting pin 106 is provided through the side wall of the receiving cavity. The limiting pin 106 passes through the sidewall of the receiving cavity and is inserted into the sidewall of the fiber optic base 101. The insertion depth of the limiting pin 106 is 30% to 50% of the wall thickness of the fiber optic base 101. The limiting pin 106 limits the displacement direction of the fiber optic base 101 and prevents the fiber optic base 101 from rotating circumferentially. When the focusing mechanism 105 is operated, the focusing mechanism 105 drives the transmission mechanism 100 to generate a rotational displacement, and then the rotational displacement of the transmission mechanism 100 drives the fiber optic base 101 to move axially. The fiber optic base 101 and the transmission mechanism 100 are provided with a coaxial hollow channel. The laser beam transmitted by the input fiber is transmitted downstream of the optical path through the hollow channel. Laser transmission module 2: located downstream of the laser receiving module 1, used to collimate and focus the laser beam and transmit the laser beam downstream of the optical path. Laser output module 3: located downstream of the optical path of the laser transmission module 2, used to output a laser beam to the workpiece to be cut. The fiber-coupled adjustable-focus laser cutting device provided in this embodiment transforms the existing motor-dependent focusing technology into a fully mechanical transmission focusing design, avoiding the failure risk of electronic components such as motors in a radiation environment. Through the coordinated cooperation of the focusing mechanism, transmission mechanism, and limit pin, a high-precision and high-reliability focusing function is achieved, realizing a laser cutting device with good radiation resistance, high long-term operational stability, and long lifespan in a nuclear radiation environment.

[0031] In one specific implementation, such as Figure 2As shown, this embodiment provides a fiber-coupled adjustable-focus laser cutting device. The transmission mechanism 100 includes a rotating sleeve 102, a horizontal bevel gear 103, and a vertical bevel gear 104. The focusing mechanism 105 is a rotatable focusing handle. The first end of the fiber optic base 101 is fixedly connected to the input fiber. The second end of the fiber optic base is connected to the top 102 of the rotating sleeve in the receiving cavity via a threaded structure 1021. One end of the focusing handle extends out of the receiving cavity to form an operating end, and the other end is coaxially connected to the vertical bevel gear 104 in the receiving cavity. The horizontal bevel gear 103 is coaxially fixedly connected to the bottom of the rotating sleeve 102 in the receiving cavity. Three symmetrically arranged limiting pins 106 are inserted through the side wall of the receiving cavity. The limiting pins 106 are inserted into the side wall of the fiber optic base 101 through the side wall of the receiving cavity. The insertion depth of the limiting pins 106 is 35% to 45% of the wall thickness of the fiber optic base 101. The limiting pin 106 limits the fiber optic base 101 to prevent circumferential rotation and ensures that the fiber optic base 101 can only move axially. The vertical bevel gear 104 meshes with the horizontal bevel gear 103. When the focusing handle is rotated, the rotating sleeve 102 is driven to rotate through the meshing transmission of the vertical bevel gear 104 and the horizontal bevel gear 103. In turn, the fiber optic base 101 is driven to move axially through the threaded structure, thereby adjusting the distance between the output end of the input fiber and the downstream device in the optical path to achieve the focusing purpose. The fiber optic base 101 and the rotating sleeve 102 are provided with a coaxial hollow channel. The laser transmitted by the input fiber is transmitted downstream in the optical path through the hollow channel of the two to ensure that the laser beam is transmitted along the center. The laser transmission module 2 is located downstream of the laser receiving module 1 and is used to collimate and focus the laser beam and transmit the laser beam downstream in the optical path. The laser output module 3 is located downstream of the laser transmission module 2 and is used to output the laser beam and cutting gas to the workpiece to be cut. This embodiment provides a fiber-coupled adjustable-focus laser cutting device that transforms the existing motor-dependent focusing technology into a fully mechanical focusing design. The motorless design completely avoids the risk of electronic component failure in a radiation environment. Through the coordinated operation of the vertical bevel gear 104, the horizontal bevel gear 103, the threaded structure 1021, and the limiting pin 106, a high-precision and high-reliability focusing function is achieved. This results in a spent fuel rod laser cutting device with good radiation resistance, high stability, and long lifespan in a nuclear radiation environment. Exemplarily, the transmission mechanism 100 can also be a gear and rack transmission mechanism, a worm gear transmission mechanism, or a lead screw and nut transmission mechanism.

[0032] In one specific embodiment, the operating end of the focusing handle is provided with a handle 1051 for the robotic arm to grip. When the robotic arm grips the handle 1051, the focusing handle is rotated to realize the axial movement of the fiber optic base 101, which can realize remote focusing and avoid personnel radiation exposure.

[0033] like Figures 3-4As shown, in one specific embodiment, the laser transmission module 2 includes a mounting cavity 20, which includes a first laser transmission channel 201 and a second laser transmission channel 202. The first laser transmission channel 201 is coaxially connected to the hollow channel of the rotating sleeve 102. A first parabolic reflector 203 and a second parabolic reflector 204 are coaxially mounted inside the mounting cavity 20. The laser beam upstream of the optical path is transmitted from the first laser transmission channel 201 and collimated by the first parabolic reflector 203 to form a parallel laser beam. It is then focused by the second parabolic reflector 204 to form a focused beam. The second laser transmission channel 202 is coaxially connected to the laser output module 3. The collimated and focused laser beam 205 is transmitted downstream of the optical path through the second laser transmission channel 202. In one specific embodiment, the mirror substrate of the first parabolic reflector 203 and the second parabolic reflector 204 is made of oxygen-free copper. Oxygen-free copper has stable performance and is not easily deformed, which ensures the long-term stability of the laser transmission module 2 and extends the service life of the fiber-coupled adjustable focus laser cutting device provided in this embodiment.

[0034] In one specific embodiment, the mounting cavity 20 is made of stainless steel or lead, which can protect the internal components of the mounting cavity 20, the first parabolic reflector 203 and the second parabolic reflector 204, from radiation damage, improve the stability of the first parabolic reflector 203 and the second parabolic reflector 204, and increase the lifespan of the laser cutting device.

[0035] like Figures 5-7 As shown, in one specific embodiment, a cooling cavity 2010 is provided inside the first parabolic reflector 203 and / or the second parabolic reflector 204. A coolant inlet 2011 and a coolant outlet 2012 penetrate the sidewall of the mounting cavity 20 and communicate with the cooling cavity 2010 inside the first parabolic reflector 203 and / or the second parabolic reflector 204. The cooling cavity 2010 is provided with N flow-guiding heat dissipation fins 2013, where N is greater than or equal to 2. Each flow-guiding heat dissipation fin 2013 extends from the coolant inlet 2011 end to the coolant outlet 2012 end, and a coolant flow channel 2014 is formed between two adjacent flow-guiding heat dissipation fins. Furthermore, as... Figure 7As shown, the heat dissipation fins 2013 have an inclination angle α of 15°±2° along the flow direction of the cooling liquid. The height ratio of each heat dissipation fin 2013 to the width ratio of the cooling cavity 2010 is 1:4-1:1.5. The cooling cavity and the heat dissipation fins quickly remove the heat from the first parabolic reflector 203 and / or the second parabolic reflector 204, maintaining the stability of the laser cutting equipment. Furthermore, the heat dissipation fins 2013 adopt a gradient porous structure. Along the coolant flow direction, the porosity of the heat dissipation fins 2013 gradually changes from 35% on the coolant inlet side to 15% on the coolant outlet side. The porosity is the ratio of the void volume of the porous structure inside the heat dissipation fins 2013 to the volume of the heat dissipation fins 2013. The pores refer to through-holes perpendicular to the coolant flow direction that penetrate the heat dissipation fins 2013. The porosity can be achieved through different arrangement densities of the same pore size or different pore sizes of the same arrangement density. Figure 7 The diagram shows that through holes of different diameters are arranged on the heat dissipation fins 2013, so that the porosity of the heat dissipation fins 2013 gradually decreases from the coolant inlet side to the coolant outlet side. The porous region between two adjacent heat dissipation fins 2013 forms a gradient flow channel. The porosity gradient reduces the flow channel pressure by 18%-22% and increases the heat transfer coefficient by 25%-30%. In addition, each heat dissipation fin has a 100nm±10% nano-scale alumina coating on its surface.

[0036] like Figures 8-9As shown, in one specific embodiment, a fiber-coupled adjustable-focus laser cutting device is provided, which also includes an integrated module 4. The integrated module 4 includes a base 410, which contains a coolant circulation system, a cutting gas supply system, and a protective gas supply system. Specifically, the base 410 is provided with a first to an eighth connector and a locking head. The coolant circulation system includes: a first connector 401 connected in parallel to the coolant inlet 2011 of the first parabolic reflector 203 and the second parabolic reflector 204 via a pipeline (not shown in the figure); a second connector 402 connected in parallel to the coolant outlet 2012 of the first parabolic reflector 203 and the second parabolic reflector 204 via a pipeline; one end of a fifth connector 405 connected to a coolant source device (not shown in the figure), and the other end connected to the first connector 401 through a first through hole 411 inside the base 410; one end of a seventh connector 407 connected to a coolant recovery device (not shown in the figure), and the other end connected to the first connector 401 through a second through hole 412 inside the base 410. The two connectors 402 are connected; the cutting gas supply system includes: the third connector 403 is connected to the laser output module 3 through a pipeline, one end of the sixth connector 406 is connected to the compressed air supply device (not shown in the figure), and the other end is connected to the third connector 403 through the third through hole 413 inside the base 410. Compressed air and laser beam are simultaneously transmitted to the spent fuel rod to be cut. The laser beam acts on the spent fuel rod to cut it, and the compressed air blows away the molten material; the protective gas supply system includes the fourth connector 404 connected in sequence through a pipeline (not shown in the figure) and the through hole inside the mounting cavity 20 between the first parabolic reflector 203 and the second parabolic reflector 204. One end of the eighth connector 408 is connected to the protective gas source device (not shown in the figure), and the other end is connected to the fourth connector 404 through the fourth through hole 414 inside the base 410. The protective gas source is nitrogen or argon, which is introduced into the vicinity of the surface of the first parabolic reflector 203 and the second parabolic reflector 204 to isolate the mirror body from air or water vapor and form a protective effect on the mirror body. The first through hole 411 to the fourth through hole 414 inside the substrate 410 are independent and not interconnected. The integrated module 4 integrates the coolant circulation system, the cutting gas supply system, and the protective gas supply system, realizing centralized setup and installation of each system, improving the compactness of the device, simplifying the installation process, and enhancing maintenance convenience. One side of the integrated module 4 is connected to the laser transmission module 2, and the other side is connected to the machine tool 5 through the locking head 409, realizing rapid installation of the laser cutting device and reducing the risk of radiation exposure.

[0037] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0038] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A fiber-coupled adjustable-focus laser cutting device, characterized in that: include: Laser emitter: Used to emit a laser beam and transmit the laser beam downstream of the optical path through an input optical fiber; Laser receiving module: Located downstream of the laser emitter's optical path, it connects to the input optical fiber and adjusts the position of the output end of the input optical fiber relative to the laser transmission module. The laser receiving module includes a mounting base, an optical fiber base, a transmission mechanism, and a focusing mechanism. The mounting base includes a receiving cavity. The first end of the optical fiber base is fixedly connected to the input optical fiber. The second end of the optical fiber base is connected to the transmission mechanism in the receiving cavity. One end of the focusing mechanism extends out of the receiving cavity to form an operating end, and the other end is connected to the transmission mechanism inside the receiving cavity. At least one limiting pin is provided through the side wall of the receiving cavity. The limiting pin passes through the side wall of the receiving cavity and is inserted into the side wall of the optical fiber base. The insertion depth of the limiting pin is 30% to 50% of the wall thickness of the optical fiber base. When operating the focusing mechanism, the focusing mechanism drives the transmission mechanism to generate displacement, and then the transmission mechanism drives the optical fiber base to move axially. The optical fiber base and the transmission mechanism are provided with a coaxial hollow channel. The laser transmitted by the input optical fiber is transmitted downstream of the optical path through the hollow channel. Laser transmission module: Located downstream of the laser receiving module, it is used to collimate and focus the laser beam and transmit the laser beam downstream of the optical path; Laser output module: Located downstream of the laser transmission module, it is used to output a laser beam to the workpiece to be cut; The laser transmission module includes a mounting cavity, which includes a first laser transmission channel and a second laser transmission channel. The first laser transmission channel is coaxially connected to the hollow channel of the rotating sleeve. A first parabolic reflector and a second parabolic reflector are coaxially mounted inside the mounting cavity. After the laser beam is transmitted from the first laser transmission channel, it is collimated by the first parabolic reflector to form a parallel laser beam, and then focused by the second parabolic reflector to form a focused beam. The second laser transmission channel is connected to the laser output module. The collimated and focused laser beam is transmitted downstream of the optical path through the second laser transmission channel. The first parabolic reflector and / or the second parabolic reflector are provided with a cooling cavity. The coolant inlet and coolant outlet pass through the side wall of the mounting cavity and communicate with the cooling cavity inside the first parabolic reflector and / or the second parabolic reflector. The cooling cavity is provided with N flow-guiding heat dissipation fins, where N is greater than or equal to 2. Each flow-guiding heat dissipation fin extends from the coolant inlet end to the coolant outlet end, and a coolant flow channel is formed between two adjacent flow-guiding heat dissipation fins.

2. The fiber-coupled adjustable-focus laser cutting device according to claim 1, characterized in that: The transmission mechanism includes a rotating sleeve, a vertical bevel gear, and a horizontal bevel gear. The focusing mechanism is a rotatable focusing handle. One end of the focusing handle is coaxially connected to the vertical bevel gear in the receiving cavity. The horizontal bevel gear is coaxially fixedly connected to the bottom of the rotating sleeve. The vertical bevel gear meshes with the horizontal bevel gear. The second end of the optical fiber base is threadedly connected to the rotating sleeve. The optical fiber base and the rotating sleeve are provided with a coaxial hollow channel.

3. The fiber-coupled adjustable-focus laser cutting device according to claim 1, characterized in that: The operating end of the focusing mechanism is equipped with a handle for the robotic arm to grip.

4. The fiber-coupled adjustable-focus laser cutting device according to claim 1, characterized in that: It also includes an integrated module, which includes a base on which first to eighth connectors and a locking head are provided. The first connector is connected in parallel to the coolant inlets of the first and second parabolic reflectors via pipelines. The second connector is connected in parallel to the coolant outlets of the first and second parabolic reflectors via pipelines. One end of the fifth connector is connected to the coolant, and the other end is connected to the first connector through a first through hole inside the base. One end of the seventh connector is connected to the coolant recovery device, and the other end is connected to the second connector through a second through hole inside the base. The third connector is connected to the laser output module via pipelines. One end of the sixth connector is connected to the compressed air supply device, and the other end is connected to the third connector through a third through hole inside the base. The fourth connector is connected sequentially between the first and second parabolic reflectors via pipelines and through holes inside the mounting cavity. One end of the eighth connector is connected to the protective gas source, and the other end is connected to the fourth connector through a fourth through hole inside the base. One side of the integrated module is connected to the laser transmission module, and the other side is connected to the machine tool via the locking head.

5. The fiber-coupled adjustable-focus laser cutting device according to claim 1, characterized in that: The mirror substrates of the first and second parabolic reflectors are made of oxygen-free copper.

6. The fiber-coupled adjustable-focus laser cutting device according to claim 1, characterized in that: The mounting cavity is made of stainless steel or lead.

7. The fiber-coupled adjustable-focus laser cutting device according to claim 1, characterized in that: The heat dissipation fins have an inclination angle of 15°±2° along the direction of coolant flow, and the height of each heat dissipation fin is in the ratio of the width of the cooling cavity to 1:4-1:1.

5.

8. The fiber-coupled adjustable-focus laser cutting device according to claim 1, characterized in that: The heat dissipation fins adopt a gradient porous structure, and the porosity of the heat dissipation fins gradually changes from 35% on the coolant inlet side to 15% on the coolant outlet side along the coolant flow direction.

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