Milling tool, milling equipment and temperature control method based on laser cooling

Abstract

The invention discloses a milling tool, a milling device and a temperature control method based on laser refrigeration; the milling tool comprises a disc milling cutter and a laser refrigeration module. The laser refrigeration module comprises a refrigeration component. A refrigeration component is installed on each tooth of the disc milling cutter. The refrigeration component comprises a plane reflector, a refrigeration element and a concave reflector. The reflective surfaces of the plane reflector and the concave reflector face each other and are arranged at intervals. A refrigeration inner cavity is formed between the concave reflector and the plane reflector. The refrigeration element is arranged in the refrigeration inner cavity. A through hole is provided on the plane reflector. The through hole on the plane reflector is staggered from the main optical axis of the concave reflector. A plurality of light-transmitting windows are arranged on the side of the refrigeration element. The invention arranges a plane reflector and a concave reflector on both sides of the refrigeration element respectively, so as to increase the path length of the refrigeration element passing through the refrigeration element in the refrigeration element, thereby improving the refrigeration efficiency of the milling cutter.

Description

Technical Field

[0001] The invention belongs to the technical field of tool cooling, and in particular relates to a milling tool and milling equipment and a temperature control method based on laser refrigeration. Technical Background

[0002] During the machining of polymers and biomaterials, the workpiece is squeezed and deformed by the tool, and friction occurs between the workpiece and the tool. A large amount of cutting heat is generated in this process. If the cutting heat is not discharged in time, the polymer will melt after being heated, causing thermal deformation, the biological structure of the biomaterial will be destroyed, and the tool will also suffer thermal wear, which will reduce the tool life and lead to a decrease in machining accuracy, which greatly limits the machining efficiency. At present, the machining area is mainly cooled by external refrigeration in cutting processing, such as adding cutting fluid or spraying low-temperature gas into the cutting area. However, the processing of ultra-clean parts such as chip semiconductors has extremely high requirements for the environment, and impurities are often not allowed to enter the processing area. The cutting of biomaterials requires a large amount of saline solution, which will cause great waste, and the expensive coolant circulation system will also increase costs. Tool cooling during processing faces severe challenges.

[0003] The temperature control of the tool tip during processing plays an extremely important role. Laser cooling reduces the temperature of a material by irradiating a laser of a specific wavelength to a material of a specific material to reduce the thermal motion of atoms in the material. It is a clean and efficient cooling method with a wide range of applications, but there is currently little research on the application of laser cooling in cutting tools. Patent No.: CN212665839U uses laser irradiation of lithium yttrium fluoride crystals or glass to achieve single-point cooling of the grinding wheel cutting area. This method transmits the laser through the air, and the complex particles in the air will have an unknown effect on the laser, thereby affecting the cooling effect; in addition, this invention only aims at single-point cooling of the grinding wheel cutting area, and the external cooling effect is poor; and there is no more specific solution for temperature control. Summary of the invention

[0004] The purpose of the present invention is to provide a milling tool, a milling device and a temperature control method based on laser refrigeration, so as to realize self-refrigeration and temperature control of the tool during the cutting process.

[0005] In a first aspect, the present invention provides a laser refrigeration milling tool, which includes a disc milling cutter and a laser refrigeration module. The laser refrigeration module includes a refrigeration component. A refrigeration component is installed on each tooth of the disc milling cutter. The refrigeration component includes a plane reflector, a refrigeration element and a concave reflector. The refrigeration element adopts a laser refrigeration material. The reflective surfaces of the plane reflector and the concave reflector are opposite to each other and are arranged at intervals. A refrigeration cavity is formed between the concave reflector and the plane reflector. The refrigeration element is arranged in the refrigeration cavity. A through hole is provided on the plane reflector. The through hole on the plane reflector is staggered from the main optical axis of the concave reflector. A plurality of light-transmitting windows are arranged on the side of the refrigeration element. During operation, laser light is input into the refrigeration cavity from the through hole on the plane reflector, and is reciprocatedly reflected between the plane reflector and the concave reflector.

[0006] Preferably, the laser refrigeration module further comprises an optoelectronic slip ring, an optoelectronic hybrid cable and a reflective lens. The reflective lens is fixed on the side of the plane reflector away from the concave reflector. The reflective surface of the reflective lens is inclined toward the central axis of the disc milling cutter; one end of the optoelectronic hybrid cable is connected to the optoelectronic slip ring. The other end of the optoelectronic hybrid cable is fixed on the disc milling cutter, and the light outlet is arranged along the radial direction of the disc milling cutter. The laser emitted from the light outlet of the optoelectronic hybrid cable is reflected by the reflective lens and then emitted into the through hole on the plane reflector. During operation, the externally input laser is emitted into the refrigeration inner cavity through the electric slip ring, the optoelectronic hybrid cable and the reflective lens.

[0007] Preferably, the laser refrigeration module further comprises a temperature detection component. The temperature detection component comprises an infrared receiver and an infrared optical channel. The infrared optical channel is arranged on the side of the refrigeration component. The infrared receiver is arranged at the end of the infrared optical channel and faces the corresponding blade teeth. The signal line of the infrared receiver is led out through the optoelectronic hybrid cable and the optoelectronic slip ring.

[0008] Preferably, the middle portion of the optoelectronic hybrid cable protrudes toward a side close to the central axis of the disc milling cutter.

[0009] Preferably, the concave reflector is a spherical concave mirror.

[0010] Preferably, a heat-conducting layer is provided between the concave reflector and the corresponding blade teeth, and the heat-conducting layer is made of a flexible heat-conducting silicone sheet.

[0011] Preferably, the laser refrigeration material is nano-cadmium sulfide.

[0012] In a second aspect, the present invention provides a laser-cooled milling device, which includes a frame, a workbench, a milling drive mechanism, the aforementioned milling tool, a fixture, a laser transmitter, and a control module. The workbench and the milling drive mechanism are both mounted on the frame. The fixture is mounted on the workbench. The disc milling cutter is mounted on the spindle of the milling drive mechanism. A spindle support for mounting the spindle is provided on the milling drive mechanism. An optoelectronic slip ring is mounted between the spindle support and the spindle. The signal line of the infrared receiver is connected to the control module via the optoelectronic slip ring; the laser output by the laser transmitter is transmitted to each refrigeration component via the input optical fiber and the optoelectronic slip ring. The laser transmitter is controlled by the control module.

[0013] Preferably, the input optical fiber is erbium-doped optical fiber.

[0014] In a third aspect, the present invention provides a temperature control method for a laser-cooled milling tool during a milling process, which is specifically as follows:

[0015] When a disc milling cutter is used to mill a workpiece, the temperature of the teeth of the disc milling cutter increases; the laser is injected into the cooling cavity between the concave reflector and the plane reflector, and is reflected back and forth between the plane reflector and the concave reflector. The anti-Stokes fluorescence generated by the cooling element irradiated by the laser is emitted through the light-transmitting window to take away the heat, and the temperature of the teeth decreases. The infrared receiver detects the intensity of the infrared radiation radiated by the teeth to obtain the temperature of the teeth; when the measured temperature is greater than the upper limit of the preset range, the laser power is increased and / or the laser wavelength is reduced. When the measured temperature is less than the lower limit of the preset range, the laser power is reduced and / or the laser wavelength is increased.

[0016] The beneficial effects of the present invention are:

[0017] 1. The present invention reduces the temperature of the tool head by irradiating semiconductor nanomaterials with laser of a specific wavelength to excite anti-Stokes fluorescence; and the present invention respectively arranges a plane reflector and a concave reflector on both sides of the cooling element, thereby increasing the path length of the cooling element in the cooling element and improving the cooling efficiency of the milling cutter; thereby providing a highly efficient, vibration-free, clean and pollution-free tool cooling method.

[0018] 2. The present invention provides a light-transmitting window on the side of the refrigeration inner cavity, which can take away the anti-Stokes fluorescence with heat from the inside of the tool without affecting the cutting strength of the tool.

[0019] 3. The present invention detects the infrared light radiated by each tooth through an infrared receiver to detect the temperature of the tooth, and adjusts the cooling effect by adjusting the laser power and wavelength to achieve low-latency control of the milling cutter processing temperature. It can also promptly detect and eliminate faults in the cooling system on a certain tooth to prevent excessive wear of the tool due to uneven temperature.

[0020] 4. The present invention uses II-VI semiconductor nanomaterial cadmium sulfide as a laser refrigeration material, which can continue to reduce the temperature under low temperature conditions of -173°C through 532nm laser irradiation, and can effectively refrigerate the milling cutter. In addition, the present invention transmits the laser to the laser refrigeration module through a gain fiber doped with the rare earth element erbium Er3+. The gain fiber has stable transmission efficiency and laser gain effect, which can increase the refrigeration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention.

[0022] Figure 2 It is a schematic diagram of the installation of the refrigeration component and the temperature detection component in the present invention.

[0023] Figure 3 It is a temperature control flow chart of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

[0025] like Figure 1 As shown, a milling device based on laser refrigeration includes a frame, a workbench, a milling drive mechanism, a disc milling cutter 5, a fixture 6, a laser refrigeration module and a control module 10. The workbench and the milling drive mechanism are both mounted on the frame. The fixture 6 is mounted on the workbench for clamping the workpiece. The disc milling cutter 5 is mounted on the spindle of the milling drive mechanism, which can rotate and move under the drive of the milling drive mechanism. A spindle support 7 for mounting the spindle is provided on the milling drive mechanism.

[0026] The laser refrigeration module includes an optical fiber connector 1, an optoelectronic slip ring 2, an input optical fiber 3, an optoelectronic hybrid cable 4, a laser transmitter 9, a refrigeration component and a temperature detection component. The input optical fiber 3 adopts erbium-doped optical fiber. The optical fiber connector 1 is fixed on the spindle support 7. The fixed part of the optoelectronic slip ring 2 is fixed to the spindle support 7. The rotating part of the optoelectronic slip ring 2 is fixed to the spindle. The fixed part of the optoelectronic slip ring 2 is provided with a light inlet, and the rotating part is provided with n light outlets. n is the number of teeth 19 of the disc milling cutter 5; all light outlets on the optoelectronic slip ring 2 are connected to the light inlet. The light inlet of the optoelectronic slip ring 2 is connected to the laser output interface of the laser transmitter 9 through the optical fiber connector 1 and the input optical fiber 3. The control module 10 includes a controller and a laser signal generator. The signal output interface of the laser signal generator is connected to the control interface of the laser transmitter 9. The controller adjusts the laser intensity and wavelength output by the laser transmitter 9 through the laser signal generator.

[0027] like Figure 2As shown, a refrigeration component and a temperature detection component are installed on the top of each tooth 19 of the disc milling cutter 5. The n refrigeration components are respectively connected to the n light outlets of the optoelectronic slip ring 2 through the optical transmission core wires of n optoelectronic hybrid cables 4. The refrigeration component includes a laser emission hole 11, a reflector lens 13, a plane reflector 15, a refrigeration element 16, a light-transmitting window 17, a heat-conducting layer 18, a tooth 19 and a concave reflector 20.

[0028] The cooling element 16 uses a laser cooling material, which can release fluorescence and reduce the temperature under the irradiation of a laser with a specific emission wavelength. The heat conductive layer 18 uses a flexible heat conductive silicone sheet. The laser cooling material is a semiconductor nanomaterial cadmium sulfide. In this embodiment, the semiconductor nanomaterial cadmium sulfide is specifically a II-VI semiconductor nano cadmium sulfide material, and its emission wavelength is 500 to 550 nm.

[0029] The concave reflector 20 adopts a spherical concave mirror; the back of the concave reflector 20 is fixed to the top surface of the corresponding tooth 19 on the disc milling cutter 5 through a heat conductive layer 18. The concave reflective surface of the concave reflector 20 faces directly upward. The plane reflector 15 with the reflective surface facing downward is fixed on the disc milling cutter 5 and is located directly above the concave reflector 20. A refrigeration cavity is formed between the concave reflector 20 and the plane reflector 15. The refrigeration element 16 is arranged in the refrigeration cavity. A through hole is opened in the middle of the plane reflector 15. The through hole on the plane reflector 15 is staggered from the main optical axis of the concave reflector 20, so that the laser injected from the through hole on the plane reflector 15 will not be directly emitted from the through hole on the plane reflector 15 after one reflection on the concave reflector 20. One or more light-transmitting windows 17 are arranged on the side of the refrigeration element 16, and the cutting strength of the tooth will not be affected. The light-transmitting window 17 is used to release the fluorescence generated by the cooling element 16 under the irradiation of the laser, thereby releasing heat.

[0030] The optical fiber connection block made of transparent material is fixed on the top surface of the plane reflector. The reflector lens 13 is arranged inside the optical fiber connection block. The reflective surface of the reflector lens 13 is inclined toward the disc milling cutter 5 and is at an angle of 45° with the horizontal plane; the optoelectronic hybrid cable 4 is fixed to the corresponding optical fiber connection block, and the light outlet hole 10 is arranged along the radial direction of the disc milling cutter 5 and toward the reflective surface of the reflector lens 13. The laser emitted from the light outlet hole 10 of the optoelectronic hybrid cable 4 is reflected by the reflector lens 13 and then emitted into the through hole on the plane reflector 15. The laser reflected by the reflector lens 13 is parallel to the main optical axis of the concave reflector 20.

[0031] The input end of the optoelectronic hybrid cable 4 is vertically arranged upward, the output end is arranged radially outward along the disc milling cutter, and the middle part is convex to the side close to the central axis of the disc milling cutter. During the high-speed rotation of the disc milling cutter, the optoelectronic hybrid cable 4 convex to the inside can use its own elasticity to offset the influence of the centrifugal effect, thereby improving the stability of the laser refrigeration module.

[0032] During operation, the laser emitted by the laser emitter 9 enters the refrigeration cavity through the input optical fiber 3, the optical fiber connector 1, the optoelectronic slip ring 2, the optoelectronic hybrid cable 4 and the reflective lens. The incident laser (solid line part) entering the refrigeration cavity passes through the refrigeration element. The refrigeration element will produce a refrigeration effect after being irradiated by the laser; the laser will be reflected multiple times (dashed line part) between the plane / concave mirror combination in the refrigeration cavity to enhance the refrigeration efficiency. The anti-Stokes fluorescence generated by the refrigeration element irradiated by the laser is emitted through the light-transmitting window 17 to take away the heat, thereby realizing the refrigeration effect on the cutter teeth.

[0033] The temperature detection component includes an infrared receiver 12 and an infrared optical channel 14. The infrared optical channel 14 is arranged on the side of the refrigeration component. The infrared receiver 12 is fixed on the side of the optoelectronic hybrid cable 4 and aligned with the end of the infrared optical channel 14. The infrared receiver 12 collects the infrared rays radiated by the blade teeth 19 through the infrared optical channel 14 toward the blade teeth 19, thereby realizing the temperature detection of the blade teeth 19. The signal output interface of each infrared receiver 12 is connected to the controller of the control module 10 through the corresponding electric core wire in the optoelectronic hybrid cable 4, the electrical transmission interface of the optoelectronic slip ring 2 and the temperature signal transmission cable 8. The controller obtains the temperature of each blade tooth according to the electrical signal output by the infrared receiver 12, thereby adjusting the laser wavelength emitted by the laser transmitter.

[0034] The specific implementation process of the present invention is as follows:

[0035] The control module 10 excites a laser with a wavelength of 500 to 550 nm; the laser is emitted by the laser emitter 9, and the laser is irradiated to the optical fiber connector 1 through the input optical fiber 3; the input optical fiber 3 can stably transmit the laser, and at the same time, due to the absorption of the rare earth medium in the input optical fiber 3 during the transmission of the laser, the energy carried by the incident light excites the electrons in the medium to a higher energy level, and relaxation occurs. The electrons release energy from the high energy level to the ground state, emit photons, enhance the photon flow, and improve the refrigeration efficiency. After the laser is emitted from the light outlet of the optoelectronic hybrid cable, it irradiates the reflective lens 13, and the incident laser is reflected to the refrigeration element 16. After the refrigeration element 16 is irradiated with a laser of a specific wavelength, the thermal motion of the atoms therein will be hindered by the photons in the laser, and its temperature will drop. When the incident laser irradiates the concave lens 17 at the bottom of the refrigeration element, it will be reflected to the plane mirror 13 above it. Such multiple reflections increase the laser irradiation distance, and the laser refrigeration efficiency is enhanced. At the same time, the cooling element 16 will stimulate anti-Stokes fluorescence with a wavelength smaller than the incident laser, and the fluorescence will be emitted through the light-transmitting window 17 to take away the heat. The cold energy generated by the cooling element is transferred to the blade teeth 19 through the heat-conducting layer 18, thereby realizing the cooling of the blade teeth 19. At the same time, the heat-conducting layer 18 made of flexible material can play a buffering and protective role for the cooling element 16 when the blade teeth 19 are performing cutting operations.

[0036] The process and conditions for the refrigeration element 16 to produce a refrigeration effect are as follows:

[0037] 1. Absorption of photons and thermal relaxation (absorption of heat) by the cooling element: The laser photons and atoms with the same wavelength of thermal motion in the cooling element will combine together.

[0038] 2. The cooling element spontaneously radiates fluorescent photons and thermally relaxes (releases heat): the atoms undergo energy level transitions, their own movement speed decreases, and then photons are emitted in the opposite direction of the atomic movement, while acting on the atoms with an impulse in the opposite direction, causing the atomic movement speed to further decrease, and the thermal motion speed of the atoms inside the cooling element decreases.

[0039] 3. The cooling element absorbs a laser photon with energy hν and emits an average energy of hν f The fluorescence photons carry away hν f -hν thermal energy, where hν f is the average energy of fluorescence radiation, and the cooling power P of each refrigeration cycle cool for:

[0040]

[0041] Among them, P abs is the resonant absorption power density. λ is the wavelength of incident light, λ fis the wavelength of the reflected fluorescence, and when the wavelength of the incident light is greater than the average wavelength of the fluorescence, that is, λ>λ f Laser cooling can only be achieved when

[0042] The reflected anti-Stokes fluorescence is emitted through the light-transmitting window of the tool to take away the heat in the cooling element.

[0043] like Figure 3 As shown, the method for controlling the temperature of the milling equipment based on laser cooling during the milling process is as follows:

[0044] Temperature control process: As the cutting operation proceeds, the cutter teeth 19 generate heat due to friction and extrusion with the workpiece, and the cutter teeth 19 radiate thermal infrared rays. The energy of the infrared rays is related to the temperature of the cutter teeth 19, and the energy of the infrared rays will change at different temperatures.

[0045] A preset temperature T0 is input, and the preset temperature T0 is used as a temperature reference of the cutter tooth 19, and then the cutting operation is started.

[0046] As the cutting operation proceeds, the cutting heat generated by the blade teeth 19 increases, and the infrared light generated by the blade teeth 19 is irradiated through the light-transmitting hole 14 to the infrared receiver 12 (dotted line part) installed at the bottom of the optoelectronic hybrid cable 4. After receiving the infrared light radiated by the blade teeth 19, the infrared receiver 12 converts the optical signal into an electrical signal.

[0047] Then the optical-electrical hybrid cable transmits the electrical signal to the signal processing module integrated in the control module 10, and after processing the signal, the current temperature of the blade 19 is obtained. When the temperature of the blade 19 exceeds a certain range of the preset value, the control module starts to adjust the temperature.

[0048] When the temperature is too high, first increase the laser power to enhance the efficiency of laser cooling and reduce the laser wavelength. Increasing the laser power can significantly reduce the temperature. At the same time, due to the increase in the temperature of the cooling element, the thermal motion speed of the atoms inside it increases, and its wavelength is shorter than before. At this time, it is necessary to reduce the laser wavelength to stimulate more fluorescence to reduce the temperature.

[0049] If the temperature of the cutter teeth is too low, the cutter teeth with lower temperature are prone to stress damage during the cutting process. Therefore, the temperature of the cutter teeth is increased by adjusting the control module. At this time, only the power of the incident laser is reduced, and the temperature of the cooling element slowly rises.

Claims

1. A milling tool based on laser cooling, comprising a disc milling cutter (5); characterized in that: The invention also comprises a laser refrigeration module; the laser refrigeration module comprises a refrigeration component; each tooth (19) of the disc milling cutter (5) is equipped with a refrigeration component; the refrigeration component comprises a plane reflector (15), a refrigeration element (16) and a concave reflector (20); the refrigeration element (16) is made of laser refrigeration material; the reflective surfaces of the plane reflector (15) and the concave reflector (20) are opposite to each other and are arranged at an interval; a refrigeration inner cavity is formed between the concave reflector (20) and the plane reflector (15); the refrigeration element (16) is arranged in the refrigeration inner cavity; a through hole is provided on the plane reflector (15); the through hole on the plane reflector (15) is staggered from the main optical axis of the concave reflector (20); a plurality of light-transmitting windows (17) are arranged on the side of the refrigeration element (16); during operation, laser light is input into the refrigeration inner cavity from the through hole on the plane reflector (15), and is reciprocally reflected between the plane reflector (15) and the concave reflector (20).

2. A milling tool based on laser cooling according to claim 1, characterized in that: The laser refrigeration module further comprises an optoelectronic slip ring (2), an optoelectronic hybrid cable (4) and a reflective lens (13); the reflective lens (13) is fixed to a side of the plane reflector (15) away from the concave reflector (20); the reflective surface of the reflective lens (13) is inclined toward the central axis of the disc milling cutter (5); one end of the optoelectronic hybrid cable (4) is connected to the optoelectronic slip ring (2); the other end of the optoelectronic hybrid cable (4) is fixed to the disc milling cutter (5), and the laser emission hole (11) is arranged in a radial direction along the disc milling cutter (5); laser light emitted from the laser emission hole (11) of the optoelectronic hybrid cable (4) is reflected by the reflective lens (13) and then emitted into the through hole on the plane reflector (15); during operation, laser light input from the outside is emitted into the refrigeration inner cavity via the electrical slip ring (2), the optoelectronic hybrid cable (4) and the reflective lens (13).

3. A milling tool based on laser cooling according to claim 2, characterized in that: The laser refrigeration module further comprises a temperature detection component; the temperature detection component comprises an infrared receiver (12) and an infrared optical channel (14); the infrared optical channel (14) is arranged on the side of the refrigeration component; the infrared receiver (12) is arranged at the end of the infrared optical channel (14) and faces the corresponding blade tooth (19); and the signal line of the infrared receiver (12) is led out through the optoelectronic hybrid cable (4) and the optoelectronic slip ring (2).

4. The milling tool based on laser cooling according to claim 2, characterized in that: The middle portion of the optoelectronic hybrid cable (4) protrudes toward a side close to the central axis of the disc milling cutter.

5. The milling tool based on laser cooling according to claim 1, characterized in that: The concave reflecting mirror (20) is a spherical concave mirror.

6. The milling tool based on laser cooling according to claim 1, characterized in that: A heat-conducting layer (18) is provided between the concave reflector (20) and the corresponding blade tooth (19); the heat-conducting layer (18) is made of a flexible heat-conducting silicone sheet.

7. The milling tool based on laser cooling according to claim 1, characterized in that: The laser refrigeration material is nano-cadmium sulfide.

8. A laser cooling milling device, comprising a frame, a workbench, a milling drive mechanism, a fixture (6) and a control module (10); characterized in that: It also includes a laser transmitter (9) and the milling tool as claimed in claim 3; the workbench and the milling drive mechanism are both mounted on the frame; the fixture (6) is mounted on the workbench; the disc milling cutter (5) is mounted on the spindle of the milling drive mechanism; a spindle support (7) for mounting the spindle is provided on the milling drive mechanism; the photoelectric slip ring (2) is mounted between the spindle support (7) and the spindle; the signal line of the infrared receiver (12) is connected to the control module via the photoelectric slip ring (2); the laser output by the laser transmitter (9) is transmitted to each refrigeration component via the input optical fiber (3) and the photoelectric slip ring (2); the laser transmitter (9) is controlled by the control module.

9. The laser cooling milling device according to claim 8, characterized in that: The input optical fiber (3) is erbium-doped optical fiber.

10. A temperature control method during milling, characterized in that: The disc milling cutter (5) in the milling tool as claimed in claim 3 is used to mill a workpiece, and the temperature of the teeth of the disc milling cutter (5) increases; the laser is injected into the refrigeration cavity between the concave reflector (20) and the plane reflector (15), and is reciprocatedly reflected between the plane reflector (15) and the concave reflector (20); the anti-Stokes fluorescence generated by the refrigeration element irradiated by the laser is emitted through the light-transmitting window (17) to take away the heat, and the temperature of the teeth is reduced; the infrared receiver (12) detects the intensity of the infrared radiation radiated by the teeth to obtain the temperature of the teeth; when the measured temperature is greater than the upper limit of the preset range, the laser power is increased and / or the laser wavelength is reduced; When the measured temperature is less than a lower limit of a preset range, the laser power is reduced and / or the laser wavelength is increased.

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