Optical fiber coupling type focusable laser cutting device

Abstract

The invention relates to an optical fiber coupling type focusable laser cutting device. According to the device, a laser transmitter transmits laser through an input optical fiber; the laser receiving module comprises a mounting seat, an optical fiber base, a transmission mechanism and a focusing mechanism, the focusing mechanism drives the optical fiber base to move in the axial direction through the transmission mechanism, and motor-free focusing in the nuclear radiation environment is achieved; the laser conduction module comprises a parabolic reflector for collimating and focusing the laser; according to the laser cutting device, the focusing technology depending on a motor in the prior art is converted into full-mechanical transmission focusing design, the failure risk of electronic elements such as the motor in the radiation environment is avoided, and through cooperation of the focusing mechanism, the transmission mechanism and the limiting pin, the laser cutting efficiency is improved. The high-precision and high-reliability focusing function is achieved, and the laser cutting device which is good in radiation resistance, high in long-term operation stability and long in service life is achieved in the nuclear radiation environment.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular, to a fiber-coupled adjustable-focus laser cutting device. Background Art

[0002] Spent fuel rods (or irradiated nuclear fuel) are the spent nuclear fuel discharged after the operation of a nuclear reactor. Although most of their energy has been released through fission reactions, they still have strong radioactivity and contain recoverable nuclides. Therefore, the development of efficient and safe spent fuel rod reprocessing technologies is crucial in this field.

[0003] As a non-contact processing method, laser cutting has good application prospects in the nuclear industry. In a nuclear radiation environment, there are still some problems with conventional laser cutting heads. For example, the motors used for focusing are prone to failure in a nuclear radiation environment. The main reasons include: the circuit boards, sensors, and insulating materials inside the motors will suffer ionization damage under strong radiation, resulting in a decrease in insulation performance, circuit short circuits, or signal distortion. Radiation may also cause the magnetic properties of permanent magnets to decay, affecting the torque and accuracy of the motors. Radiation will also accelerate the decomposition of the lubricant of the motor bearings, leading to increased mechanical wear and affecting the performance of the motors. Eventually, the stability of the laser cutting device becomes poor and its lifespan becomes short.

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

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

[0006] To achieve the above object, 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 along the optical path through an input optical fiber; a laser receiving module: located downstream of the optical path of the laser emitter, for connecting the input optical fiber and adjusting the position of the light-emitting end of the input optical fiber relative to the laser conduction 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, and 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 outside the receiving cavity to form an operation end, and the other end is connected to the transmission mechanism in the receiving cavity. At least one limit pin penetrates 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 limit 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 displace, and then drives the optical fiber base to move axially through the transmission mechanism. The optical fiber base and the transmission mechanism are provided with coaxial hollow channels, and the laser transmitted by the input optical fiber is transmitted downstream along the optical path through the hollow channels; a laser conduction module: located downstream of the laser receiving module, for collimating and focusing the laser beam and transmitting the laser beam downstream along the optical path; a laser output module: located downstream of the optical path of the laser conduction module, for outputting 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 operation end of the focusing mechanism is provided with a handle for clamping by a manipulator.

[0009] In one specific embodiment, the laser conduction 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 communicated with the hollow channel of the rotating sleeve. Inside the mounting cavity, a first parabolic mirror and a second parabolic mirror are fixedly installed coaxially. The laser beam is transmitted through the first laser transmission channel and collimated by the first parabolic mirror to form a parallel laser beam, and then focused by the second parabolic mirror to form a focused beam. The second laser transmission channel is communicated with the laser output module, and the collimated and focused laser beam is transmitted downstream along the optical path through the second laser transmission channel.

[0010] In one specific embodiment, an integration module is further included. The integration module includes a base body, on which a first to an eighth connector and a locking head are provided. The first connector is connected in parallel to the coolant inlets of the first parabolic mirror and the second parabolic mirror through pipelines. The second connector is connected in parallel to the coolant outlets of the first parabolic mirror and the second parabolic mirror through pipelines. One end of the fifth connector is connected to the coolant, and the other end is communicated with the first connector through a first through hole inside the base body. One end of the seventh connector is connected to the coolant recovery device, and the other end is communicated with the second connector through a second through hole inside the base body. The third connector is connected to the laser output module through a pipeline. One end of the sixth connector is connected to the compressed air supply device, and the other end is communicated with the third connector through a third through hole inside the base body. The fourth connector is sequentially connected to between the first parabolic mirror and the second parabolic mirror through pipelines and a through hole inside the installation cavity. One end of the eighth connector is connected to the protective gas source, and the other end is communicated with the fourth connector through a fourth through hole inside the base body. One side of the integration module is connected to the laser conduction module, and the other side is connected to the machine tool through the locking head.

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

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

[0013] In one specific embodiment, cooling cavities are arranged inside the first parabolic mirror and / or the second parabolic mirror. The coolant inlet and the coolant outlet respectively penetrate through the side wall of the installation cavity and communicate with the cooling cavities inside the first parabolic mirror and / or the second parabolic mirror. N flow guiding and heat dissipating fins are arranged in the cooling cavity, where N is greater than or equal to 2. Each flow guiding and heat dissipating fin extends from the coolant inlet end to the coolant outlet end, and a coolant flow channel is formed between two adjacent flow guiding and heat dissipating fins.

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

[0015] In one specific embodiment, the flow guiding and heat dissipating fins adopt a gradient porous structure. Along the coolant flow direction, the porosity of the flow guiding and heat dissipating fins gradually changes from 35% on the coolant inlet side to 15% on the coolant outlet side.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: A fiber-coupled adjustable-focus laser cutting device provided by the present invention converts the focus adjustment technology relying on motors in the prior art into a fully mechanical transmission focus adjustment design, avoiding the failure risk of electronic components such as motors in a radiation environment. Through the collaborative cooperation of the focus adjustment mechanism - transmission mechanism - limit pin, a high-precision and highly reliable focus adjustment function is achieved, realizing a laser cutting device with good radiation resistance, high long-term operation stability, and long service life in a nuclear radiation environment. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0018] Figure 2 FIG. is a schematic cross-sectional structure diagram of the laser receiving module in the present invention.

[0019] Figure 3 FIG. is a schematic structure diagram of the laser conduction module in the present invention.

[0020] Figure 4 FIG. is a schematic cross-sectional structure diagram of a fiber-coupled adjustable-focus laser cutting device of the present invention.

[0021] Figure 5 FIG. is a schematic structure diagram of the first parabolic mirror or the second parabolic mirror in the present invention.

[0022] Figure 6 FIG. is a schematic structure diagram of the cooling cavity of the first parabolic mirror or the second parabolic mirror in the present invention.

[0023] Figure 7 FIG. is a schematic diagram of the inclination angle and gradient porous structure of the flow guiding heat dissipation fins along the flow direction of the cooling liquid in the present invention.

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

[0025] Figure 9 FIG. is a schematic structure diagram of a fiber-coupled adjustable-focus laser cutting device of the present invention after being connected to a machine tool. DETAILED DESCRIPTION OF THE INVENTION

[0026] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It 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. Therefore, it should not be construed as a limitation to the present invention.

[0027] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0028] In the present invention, unless otherwise clearly specified and defined, terms such as "mounted", "connected", "coupled", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. 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.

[0029] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given with reference to the accompanying drawings.

[0030] In one of the specific embodiments, as Figure 1 - Figure 2As shown in the figure, a fiber-coupled adjustable-focus laser cutting device is provided, including: a laser emitter (not shown in the figure): used to emit a laser beam and transmit the laser beam downstream along the optical path through an input optical fiber (not shown in the figure); a laser receiving module 1: located downstream of the optical path of the laser emitter, used to connect the input optical fiber and adjust the position of the light-emitting end of the input optical fiber relative to the laser conduction 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 outside 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 limit pin 106 penetrates the side wall of the receiving cavity. The limit pin 106 penetrates the side wall of the receiving cavity and inserts into the side wall of the optical fiber base 101. The insertion depth of the limit pin 106 is 30% to 50% of the wall thickness of the optical fiber base 101. The limit pin 106 defines the displacement direction of the optical fiber base 101 and prevents the optical fiber base 101 from rotating circumferentially. When operating the focusing mechanism 105, the focusing mechanism 105 drives the transmission mechanism 100 to generate a rotational displacement, and then drives the optical fiber base 101 to move axially through the rotational displacement of the transmission mechanism 100. The optical fiber base 101 and the transmission mechanism 100 are provided with coaxial hollow channels, and the laser beam transmitted by the input optical fiber is transmitted downstream along the optical path through the hollow channels; a laser conduction module 2: located downstream of the laser receiving module 1, used to collimate and focus the laser beam and transmit the laser beam downstream along the optical path; a laser output module 3: located downstream of the optical path of the laser conduction module 2, used to output the laser beam to the workpiece to be cut. The fiber-coupled adjustable-focus laser cutting device provided in this embodiment converts the focusing technology relying on motors in the prior art 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 - limit pin, a high-precision and high-reliability focusing function is achieved, and a laser cutting device with good radiation resistance, high long-term operation stability, and long service life is realized in a nuclear radiation environment.

[0031] In one specific embodiment, as Figure 2As shown in the figure, 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 optical fiber base 101 is fixedly connected to the input optical fiber. The second end of the optical fiber base is connected to the top of the rotating sleeve 102 in the accommodating cavity through a threaded structure 1021. One end of the focusing handle extends outside the accommodating cavity to form an operating end, and the other end is coaxially connected to the vertical bevel gear 104 in the accommodating cavity. The horizontal bevel gear 103 is coaxially and fixedly connected to the bottom of the rotating sleeve 102 in the accommodating cavity. Three symmetrically arranged limit pins 106 are provided on the side wall of the accommodating cavity. The limit pins 106 pass through the side wall of the accommodating cavity and are inserted into the side wall of the optical fiber base 101. The insertion depth of the limit pins 106 is 35% to 45% of the wall thickness of the optical fiber base 101. The limit pins 106 limit the optical fiber base 101 to prevent the optical fiber base 101 from rotating circumferentially, ensuring that the optical fiber 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. Then, the optical fiber base 101 is driven to move axially through the threaded structure, thereby adjusting the distance between the light-emitting end of the input optical fiber and the device downstream of the optical path to achieve the focusing purpose. The optical fiber base 101 and the rotating sleeve 102 are provided with coaxial hollow channels. The laser transmitted by the input optical fiber is transmitted downstream of the optical path through the hollow channels of the two, ensuring that the laser beam is transmitted along the center. Laser conduction module 2: Located downstream of the laser receiving module 1, it is 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 laser conduction module 2, it is used to output the laser beam and cutting gas to the workpiece to be cut. The fiber-coupled adjustable-focus laser cutting device provided by this embodiment converts the focusing technology relying on motors in the prior art into a full-mechanical focusing design. The non-motor design completely avoids the risk of electronic component failure in a radiation environment. Through the coordinated cooperation of the vertical bevel gear 104 - horizontal bevel gear 103 - threaded structure 1021 - limit pins 106, a high-precision and high-reliability focusing function is achieved, realizing a spent fuel rod laser cutting device with good radiation resistance, high stability, and long life in a nuclear radiation environment. Exemplarily, the transmission mechanism 100 can also be a gear-rack transmission mechanism, a worm-gear transmission mechanism, or a lead screw-nut transmission mechanism.

[0032] In one specific embodiment, the operating end of the focusing handle is provided with a handle 1051 for clamping by a manipulator. When the manipulator clamps to the position of the handle 1051 and rotates the focusing handle, the axial movement of the optical fiber base 101 is realized, and remote focusing can be achieved, avoiding personnel radiation exposure.

[0033] As Figure 3 - Figure 4As shown, in one specific embodiment, the laser conduction module 2 includes an installation cavity 20. The installation cavity 20 is provided with a first laser transmission channel 201 and a second laser transmission channel 202. The first laser transmission channel 201 is coaxially communicated with the hollow channel of the rotating sleeve 102. Inside the installation cavity 20, a first parabolic mirror 203 and a second parabolic mirror 204 are fixedly installed coaxially. The laser beam in the upstream of the optical path is transmitted through the first laser transmission channel 201 and collimated by the first parabolic mirror 203 to form a parallel laser beam, and then focused by the second parabolic mirror 204 to form a convergent beam. The second laser transmission channel 202 is coaxially communicated with the laser output module 3. The collimated and focused laser beam 205 is transmitted downstream along the optical path through the second laser transmission channel 202. In one specific embodiment, the mirror substrates of the first parabolic mirror 203 and the second parabolic mirror 204 are made of oxygen-free copper. The oxygen-free copper material has stable performance and is not easy to deform, ensuring the long-term operation stability of the laser conduction module 2 and extending the service life of the fiber-coupled adjustable-focus laser cutting device provided in this embodiment.

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

[0035] As Figure 5 - Figure 7 shown, in one specific embodiment, a cooling cavity 2010 is provided inside the first parabolic mirror 203 and / or the second parabolic mirror 204. The coolant inlet 2011 and the coolant outlet 2012 respectively penetrate through the side wall of the installation cavity 20 and communicate with the cooling cavity 2010 inside the first parabolic mirror 203 and / or the second parabolic mirror 204. N flow guiding and heat dissipating fins 2013 are provided in the cooling cavity 2010, where N is greater than or equal to 2. Each flow guiding and heat dissipating fin 2013 extends from the coolant inlet 2011 end to the coolant outlet 2012 end, and a coolant flow channel 2014 is formed between adjacent two flow guiding and heat dissipating fins. Further, as Figure 7As shown, the flow guiding and heat dissipating fin 2013 has an inclination angle α of 15° ± 2° along the direction of the cooling liquid flow. The ratio of the height of each flow guiding and heat dissipating fin 2013 to the width of the cooling cavity 2010 is 1:4 - 1:1.5. The cooling cavity and the flow guiding and heat dissipating fins quickly remove the heat of the first parabolic mirror 203 and / or the second parabolic mirror 204, maintaining the stability of the laser cutting device. Further, the flow guiding and heat dissipating fin 2013 adopts a gradient porous structure. Along the direction of the coolant flow, the porosity of the flow guiding and heat dissipating fin 2013 gradually changes from 35% on the coolant inlet side to 15% on the coolant outlet side. The porosity refers to the ratio of the void volume of the porous structure inside the flow guiding and heat dissipating fin 2013 to the volume of the flow guiding and heat dissipating fin 2013. The voids refer to the through holes perpendicular to the direction of the coolant flow and penetrating the flow guiding and heat dissipating fin 2013. The porosity can be achieved by different pore diameters with the same arrangement density or the same pore diameter with different arrangement densities, where Figure 7 It shows that by arranging through holes with different pore diameters on the flow guiding and heat dissipating fin 2013, the porosity of the flow guiding and heat dissipating fin 2013 gradually decreases from the coolant inlet side to the coolant outlet side. The porous area between two adjacent flow guiding and heat dissipating fins 2013 forms a gradient flow channel. Its porosity gradient reduces the flow channel pressure by 18% - 22% and increases the heat transfer coefficient by 25% - 30%. And a nano-scale alumina coating with a thickness of 100nm ± 10% is provided on the surface of each flow guiding and heat dissipating fin.

[0036] As Figure 8 - Figure 9As shown, in one specific embodiment, a fiber-coupled adjustable-focus laser cutting device is provided, further including an integrated module 4. The integrated module 4 includes a base body 410. Inside the base body 410, there are a coolant circulation system, a cutting gas supply system, and a protective gas supply system. Specifically: on the base body 410, there are first to eighth connectors and a locking head. Among them, the coolant circulation system includes: the first connector 401 is connected in parallel through a pipeline (not shown in the figure) to the coolant inlets 2011 of the first paraboloidal mirror 203 and the second paraboloidal mirror 204. The second connector 402 is connected in parallel through a pipeline to the coolant outlets 2012 of the first paraboloidal mirror 203 and the second paraboloidal mirror 204. One end of the fifth connector 405 is connected to a coolant source device (not shown in the figure), and the other end is communicated with the first connector 401 through the first through hole 411 inside the base body 410. One end of the seventh connector 407 is connected to a coolant recovery device (not shown in the figure), and the other end is communicated with the second connector 402 through the second through hole 412 inside the base body 410. 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 a compressed air supply device (not shown in the figure), and the other end is communicated with the third connector 403 through the third through hole 413 inside the base body 410. Compressed air and the laser beam are transmitted to the spent fuel rod to be cut at the same time. 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, which is connected in sequence through a pipeline (not shown in the figure) and the through hole inside the installation cavity 20 to between the first paraboloidal mirror 203 and the second paraboloidal mirror 204. One end of the eighth connector 408 is connected to a protective gas source device (not shown in the figure), and the other end is communicated with the fourth connector 404 through the fourth through hole 414 inside the base body 410. The protective gas source is nitrogen or argon, which is introduced near the surfaces of the first paraboloidal mirror 203 and the second paraboloidal mirror 204 to isolate the mirror body from air or water vapor and form protection for the mirror body. Among them, the first through hole 411 to the fourth through hole 414 inside the base body 410 are independent of each other and do not communicate with each other. The integrated module 4 integrates the coolant circulation system, the cutting gas supply system, and the protective gas supply system together, realizes the centralized setting and installation of each system, improves the compactness of the device, simplifies the installation process, and improves the convenience of maintenance. One side of the integrated module 4 is connected to the laser conduction module 2, and the other side is connected to the machine tool 5 through the locking head 409, realizing the rapid installation of the laser cutting device and reducing the radiation exposure risk.

[0037] It should be noted that it is obvious to those skilled in the art 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 features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0038] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A fiber-coupled adjustable-focus laser cutting device, characterized in that: Including: Laser emitter: It is used to emit a laser beam and transmit the laser beam downstream along the optical path through an input optical fiber; Laser receiving module: Located downstream of the laser emitter along the optical path, it is used to connect the input optical fiber and adjust the position of the light output end of the input optical fiber relative to the laser conduction 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, and 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 outside the receiving cavity to form an operating end, and the other end is connected to the transmission mechanism inside the receiving cavity. At least 1 limit pin is inserted through the side wall of the receiving cavity, and the limit pin passes through the side wall of the receiving cavity and inserts into the side wall of the optical fiber base. The insertion depth of the limit 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 drives the optical fiber base to move axially through the transmission mechanism. The optical fiber base and the transmission mechanism are provided with coaxial hollow channels, and the laser transmitted by the input optical fiber is transmitted downstream along the optical path through the hollow channels; Laser conduction module: Located downstream of the laser receiving module, it is used to collimate and focus the laser beam and transmit the laser beam downstream along the optical path; Laser output module: Located downstream of the laser conduction module along the optical path, it is used to output the laser beam to the workpiece to be cut.

2. The fiber-optic coupled adjustable-focus laser cutting device according to claim 1, wherein: 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 and 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 connected to the rotating sleeve through a threaded structure. The optical fiber base and the rotating sleeve are provided with coaxial hollow channels.

3. The fiber-coupled adjustable-focus laser cutting device according to claim 1, characterized in that: The operating end of the focusing mechanism is provided with a handle for clamping by a manipulator.

4. The fiber-coupled adjustable-focus laser cutting device according to claim 1, characterized in that: The laser conduction module includes a mounting cavity. The mounting cavity 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 mirror and a second parabolic mirror are fixedly installed inside the mounting cavity coaxially. The laser beam is collimated into a parallel laser beam after passing through the first parabolic mirror after being transmitted through the first laser transmission channel, and then is focused into a focused beam after passing through the second parabolic mirror. The second laser transmission channel is connected to the laser output module, and the collimated and focused laser beam is transmitted downstream along the optical path through the second laser transmission channel.

5. A fiber-coupled adjustable-focus laser cutting device according to claim 1, wherein: It further includes an integration module. The integration module includes a base body, on which a first to an eighth connector and a locking head are provided. The first connector is connected in parallel to the coolant inlets of the first paraboloidal reflector and the second paraboloidal reflector through pipelines. The second connector is connected in parallel to the coolant outlets of the first paraboloidal reflector and the second paraboloidal reflector through pipelines. One end of the fifth connector is connected to the coolant, and the other end is communicated with the first connector through a first through hole inside the base body. One end of the seventh connector is connected to the coolant recovery device, and the other end is communicated with the second connector through a second through hole inside the base body. The third connector is connected to the laser output module through a pipeline. One end of the sixth connector is connected to the compressed air supply device, and the other end is communicated with the third connector through a third through hole inside the base body. The fourth connector is sequentially connected to between the first paraboloidal reflector and the second paraboloidal reflector through a pipeline and a through hole inside the installation cavity. One end of the eighth connector is connected to the protective gas source, and the other end is communicated with the fourth connector through a fourth through hole inside the base body. One side of the integration module is connected to the laser conduction module, and the other side is connected to the machine tool through the locking head.

6. The fiber-coupled adjustable-focus laser cutting device according to claim 4, characterized in that: The mirror substrates of the first paraboloidal reflector and the second paraboloidal reflector are made of oxygen-free copper.

7. An optical fiber coupled adjustable focus laser cutting device according to claim 4, characterized in that: The installation cavity is made of stainless steel or lead.

8. The fiber-coupled adjustable-focus laser cutting device according to claim 4, characterized in that: Cooling cavities are arranged inside the first paraboloidal reflector and / or the second paraboloidal reflector. The coolant inlet and the coolant outlet respectively penetrate through the side wall of the installation cavity and communicate with the cooling cavities inside the first paraboloidal reflector and / or the second paraboloidal reflector. N flow guiding and heat dissipating fins are arranged in the cooling cavities, where N is greater than or equal to 2. Each flow guiding and heat dissipating fin extends from the coolant inlet end to the coolant outlet end, and a coolant flow channel is formed between two adjacent flow guiding and heat dissipating fins.

9. The fiber-coupled adjustable-focus laser cutting device according to claim 8, characterized in that: The flow guiding and heat dissipating fins have an inclination angle of 15°±2° along the cooling liquid flow direction, and the ratio of the height of each heat dissipating fin to the width of the cooling cavity is 1:4 - 1:1.

5.

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

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