In-situ laser-assisted machining system based on beam shaping

Abstract

The application discloses an in-situ laser-assisted machining system based on beam shaping, which comprises a laser generating device for generating and emitting a low-power Gaussian laser; a beam shaping device for shaping the Gaussian laser into a focused beam with specific size, shape and energy distribution form according to the thermodynamic performance of the material to be machined, the size of the focused beam being smaller than the height of the cutting edge of the cutting tool from the upper surface thereof; wherein the shaping target of the beam shaping device is determined by simulating the temperature field of the material in the cutting area for different workpiece materials and different spot sizes, shapes and energy distributions, and the uniform temperature field is taken as an evaluation index; and a focal point adjusting device for adjusting the positions of the three degrees of freedom of the beam shaping device, so that the focused beam is passed through the cutting tool and emitted near the cutting edge thereof, and the laser focal plane is coincided with the machining plane. The application can effectively inhibit the surface and subsurface damage of the material to be machined and prolong the service life of the cutting tool.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ultra-precision machining, and more particularly relates to an in-situ laser-assisted machining system based on beam shaping. BACKGROUND

[0002] Optical elements of difficult-to-machine materials such as monocrystalline silicon, silicon carbide and fused quartz are widely used in space exploration, high-end weapon equipment and consumer electronics due to their excellent optical performance. Realizing nanoscale damage manufacturing of optical elements of difficult-to-machine materials and meeting the development needs of national major strategic fields are challenges and development directions of ultra-precision manufacturing technology. Diamond cutting technology is often used for high-quality forming of difficult-to-machine materials due to its high efficiency, high quality and high machining freedom. However, for brittle materials such as monocrystalline silicon, silicon carbide and fused quartz, the brittle-plastic transition critical cutting depth of diamond cutting is small, and brittle fracture of the material is prone to occur, resulting in poor surface and subsurface quality. The method of energy field assisted diamond cutting can greatly improve the machinability of difficult-to-machine materials and obtain high-quality formed surfaces.

[0003] Laser has the advantages of precise control and high energy density. The method of laser-assisted diamond cutting can effectively soften the material and improve the brittle-plastic transition critical depth, so that the material is removed in a plastic mode, improving the surface machining quality and material removal efficiency. Currently, laser-assisted diamond cutting technology is divided into pre-heating assisted cutting and in-situ laser-assisted cutting.

[0004] Among them, the laser pre-heating assisted diamond cutting technology irradiates a spot on the material to be removed area to preheat and soften the material before cutting deformation. However, due to the limitation of heat conduction, a large laser power is generally selected to ensure that the material in the cutting area is not cooled, which will result in a large heat-affected zone and cause surface and subsurface damage of the material. The in-situ laser-assisted machining technology focuses the laser through the tool near the cutting edge to effectively heat and soften the material in the cutting area and reduce the heat-affected zone. However, due to the uneven energy distribution of the Gaussian laser, the temperature is high in the center of the irradiation area and low at the edge, resulting in a large temperature gradient and still causing subsurface damage such as thermal stress. In addition, the high temperature in the center of the spot will also deteriorate the performance of the tool and accelerate the tool wear.

[0005] Therefore, how to suppress surface and subsurface damage of the workpiece and slow down tool wear is a problem to be solved. SUMMARY

[0006] In view of the defects of the prior art, the purpose of the present application is to provide an in-situ laser-assisted machining system based on beam shaping, which can effectively suppress surface and subsurface damage of the material to be machined and prolong the tool life.

[0007] To achieve the above object, the application provides an in-situ laser-assisted machining system based on beam shaping, integrated with an ultra-precision cutting machine tool, comprising:

[0008] A laser generating device for generating and emitting a Gaussian laser with a power range of 0-50 W;

[0009] A beam shaping device for shaping the Gaussian laser into a focused beam with specific size, shape and energy distribution form according to the thermodynamic properties of the material to be machined, the size of the focused beam being smaller than the height of the cutting edge of the cutting tool from the upper surface of the cutting tool in the ultra-precision cutting machine tool; wherein the shaping target of the beam shaping device is determined by simulating the temperature field of the material in the cutting area for different workpiece materials and different spot sizes, shapes and energy distributions, and taking the uniform temperature field as the evaluation index.

[0010] A focal point adjusting device for adjusting the positions of the three degrees of freedom of the beam shaping device, so that the focused beam passes through the cutting tool and is emitted near the cutting edge thereof, and the laser focal plane is coincided with the machining plane; wherein the cutting edge and the adjacent areas of the rake and flank faces of the cutting tool are in direct contact with the material in the cutting area, the emitted laser is directly absorbed by the material in the cutting area, and the laser emitted from the non-contact area of the rake face of the cutting tool with the material to be machined is used for preheating the material to be removed.

[0011] A tool adjusting device for adjusting the position of the cutting tool to facilitate tool setting during machining.

[0012] The in-situ laser-assisted machining system based on beam shaping provided by the application can, in the process of in-situ laser-assisted diamond cutting machining of difficult-to-machine material optical elements, adjust the shape, energy distribution form and focusing size of the laser according to the different thermodynamic properties of the workpiece material, so as to ensure uniform softening of the material to be removed, effectively avoid thermal damage and improve the quality of the workpiece surface and subsurface; and the low-power laser generating device is used, the size of the focused spot is in the order of hundreds of microns or less, the heat-affected area is small, the temperature of other areas remains at a low level except the material to be removed, the thermal performance degradation of the diamond tool can be avoided, and tool wear can be effectively inhibited.

[0013] In one embodiment, the shaped beam shape in the beam shaping device includes a circular spot, an elliptical spot, a square spot, a one-letter spot, a rectangular spot or a polygonal spot, and the shaped beam energy distribution form includes uniform distribution, annular distribution or flat-top Gaussian distribution.

[0014] In one of the embodiments, when the cutting tool is a diamond tool, the focal point adjusting device is used to adjust the front and back positions of the beam shaping device according to the laser focal point position offset caused by the refractive index difference of diamond and air to the laser, so as to make the laser focal plane coincide with the machining plane.

[0015] In one of the embodiments, the laser focal point position offset d is:

[0016] d = L - L / n

[0017] In the formula, L is the optical path of the focused beam in the diamond tool, and n is the refractive index of the diamond tool to the Gaussian laser.

[0018] In one of the embodiments, the diamond tool is composed of a diamond blade and a tungsten alloy tool body, the diamond blade is welded on the tungsten alloy tool body through a vacuum welding process, and the diamond blade is cut into a tool shape with a specific tool tip circular arc radius, a front angle and a back angle according to process requirements.

[0019] In one of the embodiments, the beam shaping device includes a beam shaping element and a focusing lens, and the beam shaping element is matched with the focal length of the focusing lens, the beam size and the divergence angle of the laser generating device.

[0020] In one of the embodiments, the beam shaping element is a diffractive optical element, a microlens array or an aspheric lens, and the focusing lens is an aspheric focusing lens.

[0021] In one of the embodiments, the beam shaping device further includes a lens clamp, a fixed clamping ring and a gasket.

[0022] The lens clamp is used to position and fix the beam shaping element and the aspheric focusing lens, and is integrated with the system and has an internal thread matched with the fixed clamping ring; the fixed clamping ring is used for axial fixation of the beam shaping element; and the gasket is used to protect the surface of the beam shaping element and the focusing lens from being damaged under the thrust of the fixed clamping ring.

[0023] In one of the embodiments, the laser generating device includes a laser generator, an output optical fiber and a laser output head, the output optical fiber is connected with the resonant cavity of the laser generator and the laser output head, and the laser output head and the lens clamp are fixed on the focal point adjusting device through a clamping seat.

[0024] In one of the embodiments, the laser emitter adopts a 1070nm wavelength continuous fiber laser, and the output power range is 0-50W. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1is a technical principle schematic diagram of an in-situ laser-assisted machining system based on beam shaping provided by an embodiment of the present application;

[0026] Figure 2 is a structural schematic diagram of an in-situ laser-assisted machining system based on beam shaping provided by an embodiment of the present application;

[0027] Figure 3 is a structural schematic diagram of a beam shaping device provided by an embodiment of the present application;

[0028] Figure 4 is an energy distribution diagram of a circular flat-top light spot exiting from the beam shaping device provided by an embodiment of the present application; wherein (a) is a focal plane irradiance distribution diagram; (b) is a beam cross-sectional profile;

[0029] Figure 5 is an energy distribution diagram of a circular flat-top light spot exiting from a cutting tool provided by an embodiment of the present application; wherein (a) is a focal plane irradiance distribution diagram; (b) is a beam cross-sectional profile;

[0030] Figure 6 is an energy distribution diagram of a circular flat-top light spot exiting from the beam shaping device provided by an embodiment of the present application; wherein (a) is a focal plane irradiance distribution diagram; (b) is a beam cross-sectional profile;

[0031] Figure 7 is an energy distribution diagram of a circular flat-top light spot exiting from a cutting tool provided by an embodiment of the present application; wherein (a) is a focal plane irradiance distribution diagram; (b) is a beam cross-sectional profile; DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0033] The application finds that, in the in-situ laser-assisted machining process, the temperature field of the material in the cutting area under laser irradiation is mainly determined by the laser spot. Under the same power, the spot size determines the laser energy density in the irradiation area. To ensure good softening effect under low power, the spot size should be kept in the order of magnitude of hundreds of microns or less. The spot shape determines the shape of the heating area. The material in this area is directly heated and the heat is transferred to the surrounding material in the form of heat conduction, and finally forms the material temperature field distribution under laser irradiation. The energy distribution of the spot directly affects the temperature gradient in the heating area. Taking a Gaussian laser as an example, the energy density in the central region of the spot is high, the material under irradiation heats up quickly and has a high temperature; the energy density in the edge region of the spot is low, the material under irradiation heats up slowly and has a low temperature, thus forming a large temperature gradient. In addition, the material temperature field distribution is also related to its own thermodynamic properties. The material density and specific heat capacity determine the temperature rise after absorbing laser energy, and the thermal conductivity affects the conduction speed of heat in the material, which together with the irradiation spot determines the final temperature field distribution. Therefore, to determine the temperature field distribution of the cutting area and achieve sub-surface damage suppression, the thermodynamic properties of the workpiece material, the size, shape and energy distribution of the laser emitted to the cutting edge of the cutting tool must be considered comprehensively.

[0034] To this end, the application provides an in-situ laser-assisted machining system different from the traditional one. By shaping the Gaussian laser before it is emitted to the cutting edge of the cutting tool in the ultra-precision cutting machine tool, a laser with a specific shape, energy distribution and size is generated, which uniformly heats the material in the cutting area of the workpiece, thereby avoiding the thermal affected zone and tool performance deterioration induced by the high temperature in the center of the heating spot of the Gaussian laser, and achieving the purpose of suppressing the generation of surface and sub-surface damage and slowing down the tool wear.

[0035] As shown in Figure 1 and 2 , the in-situ laser-assisted machining system based on beam shaping provided by the application includes a laser generating device 100, a beam shaping device 200, a focal point adjusting device 300 and a tool adjusting device 500. The laser generating device 100 is connected to one end of the beam shaping device 200, the beam shaping device 200 is fixed on the focal point adjusting device 300, the other end of the beam shaping device 200 is connected to the cutting tool 410 in the external ultra-precision cutting machine tool, and the cutting tool 410 is fixed on the tool adjusting device 500.

[0036] In the embodiment, the cutting tool 410 is used for cutting the workpiece 600 to be machined. Specifically, the cutting tool 410 provided in the embodiment includes a tool body and a tool insert connected to one end of the tool body, and the tool insert is composed of a rake face, a relief face, a cutting edge, an upper surface, a lower surface and a laser incidence face, wherein the rake face is connected with the relief face, and the cutting edge is formed at the joint of the rake face and the relief face. Further, the cutting tool 410 provided in the embodiment can further be provided with a tool assembly for protecting the light path passing through the cutting tool 410 from interference.

[0037] The laser generating device 100 is used for generating and emitting laser with a power range of 0-50 W and a Gaussian energy distribution. Specifically, the laser generating device 100 provided in the embodiment can adopt a low-power continuous fiber laser with a wavelength of 1070 nm, and the output power range is 0-50 W.

[0038] The beam shaping device 200 can adopt a beam shaping element 210 and a focusing lens 220, which are used for shaping the Gaussian laser into a focused light beam with a specific size, shape and energy distribution form according to the thermodynamic properties of the workpiece material, i.e. shaping the Gaussian laser into a light beam with a specific shape and energy distribution form, and focusing a small-size focused light spot which can be used for laser-assisted machining, preferably, the size of the light spot is smaller than the height of the cutting edge of the cutting tool from the upper surface of the cutting tool, so as to uniformly heat the material in the cutting area and effectively inhibit the generation of surface and subsurface damage of the workpiece.

[0039] Specifically, the design of the beam shaping device 200 provided in the embodiment is based on the simulation of the temperature field of the material under spot irradiation. The temperature field simulation research is carried out for different workpiece materials, different spot sizes and energy distributions, and the uniform temperature field is taken as the evaluation index to determine the beam shaping target. And under the premise of ensuring the shaping effect such as spot uniformity, the spot size should be as small as possible to ensure that it can be emitted near the cutting edge of the cutting tool. When the spot size is determined, for the machining materials with small thermal conductivity, a flat-top spot can be preferably used to uniformly heat the material; for the machining materials with large thermal conductivity, the flat-top spot will still cause the situation that the central region has high temperature and the edge region has low temperature due to the influence of the thermal conduction effect of the material, at this time, the flat-top spot can be replaced by a ring-shaped spot to achieve the effect of uniform heating.

[0040] The focal point adjusting device 300 can adopt a three-axis motion mechanism commonly used in the art, which contains a three-degree-of-freedom translation function. Through the up-down and left-right translation, the laser focused by the beam shaping device 200 can pass through the cutting tool and be emitted near the cutting edge of the cutting tool, and through the forward-backward translation, the defocusing amount of the laser focus can be adjusted to realize the coincidence of the laser focal plane and the machining plane, and form an ideal spot on the machining surface.

[0041] In the embodiment, the laser focused by the light beam shaping device 200 is emitted near the cutting edge of the cutting tool by adjusting the focal point adjusting device 300, the cutting edge and the adjacent area of the rake face and the relief face of the cutting tool are directly in contact with the material in the cutting area, and the emitted laser is directly absorbed by the material in the cutting area, so that the effect of optimally heating and softening the material in the cutting area is obtained. In addition, the laser emitted in the non-contact area of the rake face of the cutting tool and the material to be machined is used for preheating the material to be removed.

[0042] The tool adjusting device 400 can adopt a common roller screw structure in the art, which is used for fine adjustment of the up-down position of the cutting tool and facilitates tool setting during machining.

[0043] The in-situ laser-assisted machining system based on light beam shaping provided in the embodiment can ensure uniform heating and softening of the material to be removed, effectively avoid thermal damage, and improve the surface and subsurface quality of the workpiece during in-situ laser-assisted diamond cutting machining of the difficult-to-machine material optical element according to the different thermodynamic properties of the workpiece material, adjust the shape, energy distribution form and focusing size of the laser, and effectively inhibit tool wear.

[0044] The application will be described in detail below in combination with specific embodiments:

[0045] The application provides an in-situ laser-assisted machining system based on light beam shaping, which can form a light spot in various shapes such as a circle, an ellipse, a square, a line, and a polygon, and the energy distribution of the light spot can be in various forms such as a flat-top light spot, a ring-shaped light spot and a flat-top Gaussian distribution, and the in-situ laser-assisted machining system based on light beam shaping can be used for machining workpieces made of any material. The application will be described in detail by taking circular flat-top light spots and ring-shaped light spots as examples.

[0046] Referring to Figure 1 and Figure 2 , a specific embodiment of the application provides an in-situ laser-assisted machining system based on light beam shaping, which comprises a housing 700, and the housing 700 is internally provided with a laser generator 100, a light beam shaping device 200, a focal point adjusting device 300 and a tool adjusting device 500.

[0047] The laser generator 100 comprises a laser emitter, an output optical fiber 120 and a laser output head 130. The used laser generator is a low-power continuous optical fiber laser with a wavelength of 1070 nm, and the output power range is 0-50 W. The output optical fiber 120 is connected to the resonant cavity and the laser output head of the laser generator, and the laser output head 130 and the light beam shaping device 200 are fixed on the focal point adjusting device 300 through a clamp seat 140.

[0048] The beam shaping device 200 is the core module of the system. The beam shaping device 200 includes two optical elements: a beam shaping element 210 and a focusing lens 220. The laser beam with a Gaussian distribution is emitted from the laser generator, shaped into a circular flat-top spot by the beam shaping element 210, and then focused by the focusing lens 220. It is emitted as a small-sized flat-top spot at the cutting edge of the cutting tool 410, irradiating the cutting area and uniformly heating the workpiece material.

[0049] In this embodiment, the beam shaping element 210 can be any optical element with beam shaping function, such as a diffractive optical element (DOE), a microlens array, or an aspherical lens, and can be selected according to the required spot shape and energy distribution. When the focal length and diameter of the designed beam shaping element remain unchanged, the element can be replaced without altering the structure of the lens clamp and other parts. The focusing lens 220 can be an aspherical focusing lens. Choosing an aspherical focusing lens can reduce the number of lenses while achieving better focusing effect, helping to save space and facilitating integration with the focus adjustment device 300, the system housing 700, and ultra-precision machine tools.

[0050] like Figure 3 As shown, in addition to the beam shaping element 210 and the focusing lens 220, the beam shaping device 200 also includes a washer 230, a retaining ring 240, and a lens clamp 250. To maximize space saving and facilitate system integration, the lens clamp 250 is designed. In this embodiment, the diameter of the beam shaping element 210 is 25.4 mm, therefore the aperture size of the lens clamp 250 is designed to be 23 mm. The beam shaping element 210 is positioned axially using a positioning step, and a positive deviation is selected radially to ensure the installation of the beam shaping element 210. The positioning of the beam shaping element 210 is achieved through the retaining ring 240, and the mating thread on the retaining ring 240 and the lens clamp 250 is of specification SM1. The retaining ring 240 has a groove and can be tightened using a special retaining ring wrench. Due to the tapping process, a relief groove is machined in the inner hole of the lens clamp 250. To prevent damage to the surface of the beam shaping element 210 from compression by the retaining ring, a Teflon washer of compatible size and specifications can be installed between the beam shaping element 210 and the retaining ring. To reduce manufacturing complexity, the thread specifications at both ends of the fixture are identical to the selected washer and retaining ring.

[0051] In the present embodiment, the cutting tool 410 used is a diamond integrated tool for in-situ laser-assisted machining, which is composed of a front-end diamond blade and a tungsten alloy tool body. The diamond blade is welded on the tool body by vacuum welding process. According to the process requirements, the diamond blade is cut into a tool shape with a specific tool tip circular arc radius, rake angle, and relief angle. In the present embodiment, the diamond tool cutting edge circular arc radius is 100 nm. In the present embodiment, the diamond tool can be sharpened multiple times. When the tool is worn, a new cutting edge is obtained by removing part of the rake and relief surface material, ensuring that the tool can be reused.

[0052] Further, when the diamond tool is re-sharpened, the cutting edge position will be lowered. To ensure that the focused laser is emitted from the vicinity of the cutting edge, the tool adjusting device 500 can be used to fine-tune the up-and-down position of the tool. The tool adjusting device 500 has a precise roller screw structure 510, which can realize accurate adjustment of the tool position. Although the focal point adjusting device 300 can also adjust the up-and-down position of the laser output head, its position generally remains unchanged during the tool setting process because it is installed inside the shell 700. The implementation of the up-and-down adjustment function of the tool adjusting device greatly facilitates the tool setting process.

[0053] In the present embodiment, the focal point adjusting device 300 has three degrees of freedom of movement, which can realize up-and-down, left-and-right, and front-and-back position adjustment. By adjusting the up-and-down and left-and-right positions, the laser beam is ensured to be incident from the appropriate position to the diamond tool and emitted from the vicinity of the cutting edge. By adjusting the front-and-back position, the laser focal plane is ensured to coincide with the machining plane.

[0054] Further, when adjusting the position of the laser focal point, the amount of focal point position offset caused by the refractive index difference of the diamond tool 410 and air should be considered. In the present embodiment, for a 1070 nm wavelength laser, the refractive index of the diamond tool is 2.39, and the refractive index of the air medium is 1. The original light path will change when the focused laser beam enters the optically dense medium from the optically sparse medium, and the refraction angle will be smaller than the incident angle, resulting in a backward shift of the laser focal point position. Therefore, the focal point adjusting device 300 should be adjusted accordingly to ensure that the laser focal plane coincides with the machining plane position. The approximate calculation formula of the focal point position offset is as follows.

[0055] d = L - L / n

[0056] In the formula, d is the offset of the laser focal point position, L is the optical path of the laser in the diamond tool, and n is the refractive index of the diamond tool for a 1070 nm wavelength laser.

[0057] Further, in order to ensure that the laser light path is not disturbed by cutting fluid, chips, and dust in the air, the light path needs to be closed and protected. The shell 700 is used to protect the entire system from external pollution, and the light path is closed and protected by the shell 700.Figure 3 In order to facilitate the display of the internal structure of the system, the shell is partially hidden and sectioned, and the actual shell 700 is a closed structure. The protective window 510 is transparent sapphire material, which can prevent external cutting fluid and cutting chips and other sundries from entering the system interior while ensuring normal passage of the laser. The dust cover 420 is installed above the tool body to protect the laser light path from interference.

[0058] The present application aims to produce a laser spot with a specific shape and energy distribution form according to the processing needs of optical elements of difficult-to-machine materials, to assist diamond cutting processing. In this embodiment, by achieving uniform temperature rise of the cutting area of the workpiece 600, the purpose of reducing the heat affected zone and inhibiting subsurface damage and tool wear can be achieved. The beam shaping effect can be verified by optical simulation. Specifically, according to the parameters of the device, a model is established in the optical simulation software, and a Gaussian light source, a beam shaping element, a focusing lens and a diamond tool are established in turn. Important parameters include laser wavelength, laser generator exit spot size, beam divergence angle, material and refractive index of specific wavelength laser of each optical element, etc. In the optical simulation software, the light spot energy distribution of each cross section can be simulated by ray tracing. Figure 4 The display is the exit spot energy distribution diagram of the laser beam shaped by the beam shaping device 200 into a circular flat-top spot focal plane position. Figure 4 In (a), the irradiance distribution diagram at the exit spot focal plane is shown, Figure 4 In (b), the row cross-sectional profile is shown, which can more clearly identify the light spot energy distribution profile. It can be seen that the Gaussian light spot after shaping becomes a circular flat-top light spot with good uniformity. Due to the influence of the diamond tool structure and the refractive index, the light spot emitted by the diamond tool is different from Figure 4 The light spot shown has some differences, and its energy distribution diagram is shown in Figure 5 The circular flat-top light spot after the diamond tool becomes an elliptical flat-top light spot, and part of the lower part of the light spot profile is missing. In this embodiment, the blade edge arc radius of the cutting edge of the diamond tool is only about 100 nm, and the size of the flat-top light spot after shaping and focusing is about 200 μm, and the actual exit position is near the cutting edge and the rake face of the tool. The missing part of the lower part of the light spot is caused by the total emission of the optical fiber on the rake face of the diamond tool. Figure 5The shown light spot profile and energy distribution show that the present application can meet the intended purpose. After being conducted by the diamond tool, the light spot uniformity is good, and the purpose of uniform heating can be achieved. When the cutting edge contacts the workpiece material, the cutting edge and the positions near the rake face and the flank face will all contact the material. Since the refractive index of the workpiece material to the laser is less different from that of the diamond tool, full emission will not occur at the flank face. The emitted laser will be absorbed by the material in the cutting area. The laser emitted at the non-contact position of the rake face of the tool and the workpiece material can play the role of uniform preheating. The heated and softened material is then removed by the diamond tool without generating a heat affected zone.

[0059] Further, for workpiece materials with high thermal conductivity, the temperature at the center of the light spot irradiated by the flat-top light spot is higher than that at the edge of the light spot due to the influence of heat conduction. Shaping the Gaussian laser into a ring-shaped light spot can effectively solve this problem. Figure 6 and Figure 7 The ring-shaped light spot energy distribution through the focal plane position and the light spot energy distribution after being conducted by the diamond are shown. In this embodiment, the shaping optical element used to shape the Gaussian laser into a ring-shaped light spot is a cone mirror made of fused quartz. The diameter, focal length and other parameters of the cone mirror are consistent with those of the circular flat-top light spot shaping optical element, so it can be directly replaced without changing the positioning and fixing method.

[0060] Further, according to the processing requirements of different material optical elements, different beam shaping elements can be designed. In the design, the size and functional parameters are ensured to be compatible with the processing system, so that flexible replacement of the beam shaping element can be achieved, and the workpiece subsurface damage and tool wear can be inhibited to the greatest extent.

[0061] Those skilled in the art will readily understand that the above description is only of the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A beam shaping based in-situ laser assisted machining system integrated with an ultra-precision cutting machine, characterized in that, The application relates to a laser processing device for super-precision cutting machine tools. The laser processing device comprises: a laser generating device for generating and emitting a Gaussian laser with a power range of 0-50 W; a beam shaping device for shaping the Gaussian laser into a focused beam with specific size, shape and energy distribution form according to the thermodynamic performance of the material to be processed, the size of the focused beam being smaller than the height of the cutting tool cutting edge from the upper surface of the cutting tool in the super-precision cutting machine tool; wherein the shaping target of the beam shaping device is determined by simulating the temperature field of the material in the cutting area for different workpiece materials and different spot sizes, shapes and energy distributions, and the uniform temperature field is used as an evaluation index; a focal point adjusting device for adjusting the positions of the three degrees of freedom of the beam shaping device, so that the focused beam passes through the cutting tool and is emitted near the cutting edge of the cutting tool, and the laser focal plane is coincided with the machining plane; wherein the cutting edge of the cutting tool and the adjacent areas of the rake face and the relief face are directly contacted with the material in the cutting area, the emitted laser is directly absorbed by the material in the cutting area, and the laser emitted from the non-contact area between the rake face of the cutting tool and the material to be processed is used for preheating the material to be removed; and a tool adjusting device for adjusting the position of the cutting tool to facilitate tool setting during the machining process; wherein when the cutting tool is a diamond tool, the focal point adjusting device is used for adjusting the front and back positions of the beam shaping device according to the position offset of the laser focal point caused by the refractive index difference of the diamond and air to the laser, so that the laser focal plane is coincided with the machining plane. In the beam shaping device, the shaped beam shape comprises a circular spot, an elliptical spot, a one-character-shaped spot or a polygonal spot, and the shaped beam energy distribution form comprises a flat-top distribution or a ring-shaped distribution. d = L L / n The diamond tool is composed of a diamond blade and a tungsten alloy tool body, the diamond blade is welded on the tungsten alloy tool body through a vacuum welding process, and the diamond blade is cut into a tool shape with a specific tool tip circular arc radius, a rake angle and a relief angle according to process requirements.

2. The beam-shaping-based in-situ laser-assisted processing system according to claim 1, wherein, The beam shaping device comprises a beam shaping element and a focusing lens, the beam shaping element is matched with the focal length of the focusing lens, the beam size and the divergence angle of the laser generating device.

3. The beam-shaping-based in-situ laser-assisted processing system according to claim 1, wherein, The laser focus position offset amount d Is: The beam shaping element is a diffractive optical element, a microlens array or an aspheric lens, and the focusing lens is an aspheric focusing lens. – The beam shaping device further comprises a lens clamp, a fixed clasp and a gasket. ； wherein L is the optical path of the focused beam in the diamond tool, n is the refractive index of the diamond tool for the Gaussian laser.

4. The beam-shaping-based in-situ laser-assisted processing system according to claim 3, wherein, The lens clamp is used for positioning and fixing the beam shaping element and the aspheric focusing lens, and is integrated with the system and has an internal thread matched with the fixed clasp; the fixed clasp is used for axial fixation of the beam shaping element; and the gasket is used for protecting the surface of the beam shaping element and the focusing lens from being damaged under the thrust of the fixed clasp.

5. The beam-shaping-based in-situ laser-assisted processing system according to claim 1, wherein, The laser generating device comprises a laser generator, an output optical fiber and a laser output head, the output optical fiber is connected with the resonant cavity of the laser generator and the laser output head, and the laser output head and the lens clamp are fixed on the focal point adjusting device through a clamping seat.

6. The beam-shaping-based in-situ laser-assisted processing system according to claim 5, wherein, The laser emitter adopts a 1070nm wavelength continuous fiber laser, and the output power range is 0-50 W.

7. The beam-shaping-based in-situ laser-assisted processing system according to claim 5, wherein, ​ ​ 8. The beam-shaping-based in-situ laser-assisted processing system according to claim 7, wherein, ​ 9. The beam-shaping-based in-situ laser-assisted processing system according to claim 8, wherein, ​

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