CN110899981A - A method of laser-assisted machining of hard and brittle materials for laser-modified ultra-precision cutting - Google Patents
A method of laser-assisted machining of hard and brittle materials for laser-modified ultra-precision cutting Download PDFInfo
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- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/0093—Working by laser beam, e.g. welding, cutting or boring combined with mechanical machining or metal-working covered by other subclasses than B23K
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/352—Working by laser beam, e.g. welding, cutting or boring for surface treatment
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- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/70—Auxiliary operations or equipment
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- B28—WORKING CEMENT, CLAY, OR STONE
- B28D—WORKING STONE OR STONE-LIKE MATERIALS
- B28D1/00—Working stone or stone-like materials, e.g. brick, concrete or glass, not provided for elsewhere; Machines, devices, tools therefor
- B28D1/16—Working stone or stone-like materials, e.g. brick, concrete or glass, not provided for elsewhere; Machines, devices, tools therefor by turning
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/50—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
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- B23K2103/00—Materials to be soldered, welded or cut
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Abstract
一种激光改性超精密切削的激光辅助加工硬脆材料方法，它涉及一种激光辅助加工硬脆材料方法，具体涉及一种激光改性超精密切削的激光辅助加工硬脆材料方法。本发明为了解决目前的激光辅助车削只能应用于圆柱面车削，激光焦点与切削区域置于同一个圆周面内，这使刀具与激光焦点的几何位置关系无法保持恒定的问题。本发明的步骤为步骤一、搭建激光辅助切削平台；步骤二、将激光输出头产生的连续激光束聚焦于工件表面；步骤三、使用刀具对改性后的工件表面进行切削加工。本发明属于机械加工领域。
A laser-assisted processing method for hard and brittle materials by laser modified ultra-precision cutting relates to a method for laser-assisted processing of hard and brittle materials, in particular to a method for laser-assisted processing of hard and brittle materials by laser modified ultra-precision cutting. In order to solve the problem that the current laser-assisted turning can only be applied to cylindrical surface turning, the laser focal point and the cutting area are placed in the same circumferential surface, which makes the geometrical positional relationship between the tool and the laser focal point unable to keep constant. The steps of the present invention are: step 1, building a laser-assisted cutting platform; step 2, focusing the continuous laser beam generated by the laser output head on the workpiece surface; and step 3, using a tool to cut the modified workpiece surface. The invention belongs to the field of machining.
Description
Technical Field
The invention relates to a method for processing a hard and brittle material by laser assistance, in particular to a method for processing a hard and brittle material by laser assistance of laser modification and ultra-precision cutting, belonging to the field of machining.
Background
Hard and brittle materials such as hard alloy, ceramics, glass and the like have important application value and wide application prospect in the fields of aviation, photoelectron, medical treatment and the like, and compared with the traditional parts, the key parts made of the materials have the advantages of greatly prolonging the service life and improving the capability of resisting extreme conditions by virtue of the excellent mechanical and optical properties. However, these materials generally have greater processing difficulties, such as higher hardness, lower fracture toughness, etc., and may cause greater wear to the tool during the processing, which brings greater difficulty to the conventional machining means. Laser-assisted machining is considered to be an effective means of machining hard and brittle materials: the laser high-energy field is utilized to irradiate a processing area, so that local materials are softened or changed in phase at high temperature, and then mechanical processing is carried out. The addition of the laser field can be effective, so that the hardness of the surface of the material is reduced, and the processing difficulty is reduced. However, most laser-assisted machining methods are directed to cylindrical surface turning, the relative position of a laser and a cutter is kept unchanged, and the cutter is used for removing materials from materials which are heated by the laser and cooled. In the processing process, the position relation between the laser focus and the cutter needs to be accurately calculated and adjusted in advance, and only the surface of a certain simple shape of a workpiece can be repeatedly processed, so that the surface with a complex shape cannot be adapted; in addition, the current laser-assisted turning can only be applied to cylindrical surface turning, and the laser focus and the cutting area are arranged in the same circumferential surface, so that the geometric position relationship between the cutter and the laser focus cannot be kept constant.
Disclosure of Invention
The invention aims to solve the problem that the geometric position relationship between a cutter and a laser focus cannot be kept constant because the conventional laser-assisted turning can only be applied to cylindrical surface turning and the laser focus and a cutting area are arranged in the same circumferential surface, and further provides a laser-assisted hard and brittle material processing method based on laser modification and ultra-precision cutting.
The technical scheme adopted by the invention for solving the problems is as follows: the method comprises the following specific steps:
step one, building a laser auxiliary cutting platform;
focusing the continuous laser beam generated by the laser output head on the surface of the workpiece;
and step three, cutting the modified workpiece surface by using a cutter.
Further, the laser auxiliary cutting platform in the first step comprises a five-axis manual displacement platform and a laser processing module, and the laser processing module is installed on the five-axis manual displacement platform;
the steps of building the laser auxiliary cutting platform are as follows:
a, mounting a laser processing module on a five-axis displacement platform;
b, mounting the five-axis displacement platform on the ultra-precision machine tool;
and step C, mounting the cutter on the ultra-precision machine tool.
Furthermore, the five-axis manual displacement platform comprises a vertical Y-direction manual displacement platform, a connecting rib plate, a rotary R-direction manual displacement platform, a linear Z-direction manual displacement platform, a linear X-direction manual displacement platform and a linear W-direction manual displacement platform; the laser processing module is installed on the manual displacement platform in straight line W direction, and the manual displacement platform in straight line W direction is installed on the manual displacement platform in vertical Y direction, and the manual displacement platform in vertical Y direction is connected with the manual displacement platform in rotatory R direction through the connecting rib plate, and the manual displacement platform in rotatory R direction is installed on the manual displacement platform in straight line Z direction, and the manual displacement platform in straight line Z direction is installed on the manual displacement platform in straight line X direction.
Further, the laser processing module comprises a protective window glass, a converging mirror system, a collimating mirror system, a laser fiber, a water-cooling joint, a rear protective plate, a laser QBH output head, a base plate, a protective cover and a front protective plate; the protection window glass, the convergent mirror system and the collimating mirror system are sequentially connected from front to back, the protection window glass, the convergent mirror system and the collimating mirror system are sequentially installed in the protective cover from front to back, the collimating mirror system is connected with the laser fiber through a laser QBH output head, the front protective plate is installed at the front end of the protective cover, the rear protective plate is installed at the rear end of the protective cover, and the water-cooling connector is installed on the rear protective plate.
Further, the specific steps of focusing the continuous laser beam generated by the laser output head on the surface of the workpiece in the second step are as follows:
a, adjusting the position of a laser spot of a laser processing module on the surface of a workpiece through a five-axis displacement platform;
b, adjusting and determining the radius of the laser spot;
adjusting laser to focus on the surface of the workpiece, wherein the defocusing amount Z of the laser is 0; when Z is equal to Z+>When 0 or less than 0, the laser is in a defocusing state; when the laser generates defocusing amount, the laser spot becomes large;
c, performing a laser scanning ablation experiment to obtain three parameters of power, blackbody coating solution solubility and defocusing amount;
step d, carrying out grouping ablation research on different laser scanning speeds;
e, performing finite element simulation on the scanning process in the step d by using COMSOL software;
step f, respectively solving the temperature peak value of the model and the stress distribution of the section of the laser spot in COMSOL software processing;
and g, determining laser parameters.
Further, in the step b, according to the laser principle, the laser spot radius expression is as follows:
z in formula ①RThe length of the rayleigh band is represented,
represents the beam waist radius of the laser beam generated by the laser, and omega0Where ω (Z) denotes the laser spot radius, Z denotes the laser defocus amount, and λ denotes the laser center wavelength in equation ②.
Further, in the step b, the laser pitting time on the surface of the workpiece is 1 second.
Further, in the step c, a laser scanning ablation experiment is carried out, and the three parameters of power, the solubility of the black body coating solution and the defocusing amount are obtained by the following steps:
firstly, regulating laser power and blackbody coating solution concentration in groups; the adjusting range of the laser power is 20W-100W, and the concentration of the blackbody coating solution is 10% -20%;
carrying out microscopic observation on each ablation point and measuring the area of an ablation area, and selecting power and coating concentration which have ablation traces and no obvious black body coating residual as reasonable parameters in the ablation area;
and thirdly, adjusting the displacement of a laser system through a five-axis displacement platform to generate laser defocusing amount, wherein the numerical range of the defocusing amount is 0-45 mm, performing a grouped ablation experiment on the defocusing amount by using the laser power and the concentration parameter of the black body coating solution obtained in the previous step, observing and measuring an obtained ablation point, and selecting the defocusing amount parameter which has the largest ablation area, has the most obvious surface layer material ablation effect and does not have black body coating residue.
Further, in the step d, the three parameters of the laser power, the concentration of the black body coating solution and the defocusing amount obtained in the step c are used for carrying out a dynamic scanning ablation process experiment on the surface of the workpiece by the laser, and the laser scanning speed is obtained, wherein the formula of the laser scanning speed is as follows:
vc＝2δ·N③，
in the formula ③, N represents the spindle rotation speed of the ultra-precision machine tool, delta represents the laser ablation radius, and vcIndicating the laser scanning speed.
The invention has the beneficial effects that: aiming at the laser-assisted end face turning process, the invention provides an adjustable platform which can conveniently and rapidly focus the position of the tool nose of a turning tool by laser.
Aiming at the process parameter selection of the laser-assisted turning end face, the invention provides an adjustable platform capable of changing the process parameters such as the defocusing amount of laser, the incident angle of the laser, the distance between the focal point of the laser and the position of the tool nose of a turning tool and the like.
The laser ablation strategy of the invention improves the absorption rate of the transparent hard and brittle material to the laser energy, and realizes the basic requirement of laser-assisted turning.
The invention provides a parameter optimization method aiming at laser parameters, ultra-precision turning parameters and a matching relation between the laser parameters and the ultra-precision turning parameters in a laser-assisted end face turning processing technology.
Drawings
FIG. 1 is a schematic diagram of a laser-assisted cutting platform;
FIG. 2 is a schematic structural view of a laser processing module;
FIG. 3 is a schematic structural diagram of a five-axis manual displacement platform;
fig. 4 is a schematic illustration of a laser ablation strategy for a workpiece.
Fig. 5 is a schematic diagram of a laser scanning ablation process using COMSOL modeling.
FIG. 6 is a cross-sectional view of the ultra-precision cutting process after surface laser modification.
Fig. 4-6-blackbody coating to help absorb laser energy, 24-workpiece finite element model, 25-two-dimensional elliptical gaussian heat source laser energy density model, 26-heat affected zone cross section for laser ablation 23.
Detailed Description
The first embodiment is as follows: the present embodiment is described with reference to fig. 1 to 6, and the specific steps of the laser-assisted hard and brittle material processing method by laser-modified ultra-precision cutting according to the present embodiment are as follows:
step one, building a laser auxiliary cutting platform;
focusing the continuous laser beam generated by the laser output head on the surface of the workpiece;
and step three, cutting the modified workpiece surface by using a cutter 2.
The second embodiment is as follows: the present embodiment is described with reference to fig. 1 to 6, and in the first step of the method for laser-assisted machining of hard and brittle materials by laser-modified ultra-precision cutting according to the present embodiment, the laser-assisted cutting platform includes a five-axis manual displacement platform 3 and a laser machining module 4, and the laser machining module 4 is mounted on the five-axis manual displacement platform 3;
the steps of building the laser auxiliary cutting platform are as follows:
step A, mounting a laser processing module 4 on a five-axis displacement platform 3;
b, mounting the five-axis displacement platform 3 on the ultra-precision machine tool 1;
and step C, mounting the cutter 2 on the ultra-precision machine tool 1.
The third concrete implementation mode: the present embodiment is described with reference to fig. 1 to 6, and the five-axis manual displacement platform 3 of the laser-assisted hard and brittle material processing method by laser modified ultra-precision cutting according to the present embodiment includes a vertical Y-direction manual displacement platform 16, a connecting rib plate 17, a rotational R-direction manual displacement platform 18, a linear Z-direction manual displacement platform 19, a linear X-direction manual displacement platform 20, and a linear W-direction manual displacement platform 21; the laser processing module 4 is installed on the manual displacement platform 21 in the straight line W direction, the manual displacement platform 21 in the straight line W direction is installed on the manual displacement platform 16 in the vertical Y direction, the manual displacement platform 16 in the vertical Y direction is connected with the manual displacement platform 18 in the rotating R direction through a connecting rib plate 17, the manual displacement platform 18 in the rotating R direction is installed on the manual displacement platform 19 in the straight line Z direction, and the manual displacement platform 19 in the straight line Z direction is installed on the manual displacement platform 20 in the straight line X direction.
The fourth concrete implementation mode: the laser processing module 4 of the laser-modified ultraprecise-cutting laser-assisted hard and brittle material processing method according to the present embodiment is described with reference to fig. 1 to 6, and includes a protective window glass 5, a converging mirror system 6, a collimating mirror system 7, a laser fiber 8, a water-cooled joint 9, a rear protective plate 10, a laser QBH output head 11, a base plate 12, a protective cover 13 and a front protective plate 14; the protection window glass 5, the convergent mirror system 6 and the collimating mirror system 7 are sequentially connected from front to back, the protection window glass 5, the convergent mirror system 6 and the collimating mirror system 7 are sequentially installed in a protective cover 13 from front to back, the collimating mirror system 7 is connected with a laser fiber 8 through a laser QBH output head 11, a front protective plate 14 is installed at the front end of the protective cover 13, a rear protective plate 10 is installed at the rear end of the protective cover 13, and a water-cooling joint 9 is installed on the rear protective plate 10.
The fifth concrete implementation mode: in the second step of the method for laser-assisted machining of hard and brittle materials by laser-modified ultra-precision cutting according to the present embodiment, the specific steps of focusing the continuous laser beam generated by the laser output head on the surface of the workpiece are as follows:
a, adjusting the position of a laser spot of a laser processing module 4 on the surface of a workpiece through a five-axis displacement platform 3;
b, adjusting and determining the radius of the laser spot;
adjusting laser to focus on the surface of the workpiece, wherein the defocusing amount Z of the laser is 0; when Z is equal to Z+>When 0 or less than 0, the laser is in a defocusing state; when the laser generates defocusing amount, the laser spot becomes large;
c, performing a laser scanning ablation experiment to obtain three parameters of power, blackbody coating solution solubility and defocusing amount;
step d, carrying out grouping ablation research on different laser scanning speeds;
e, performing finite element simulation on the scanning process in the step d by using COMSOL software;
step f, respectively solving the temperature peak value of the model and the stress distribution of the section of the laser spot in COMSOL software processing;
and g, determining laser parameters.
In the embodiment, COMSOL software is used for coupling the heat transfer module and the solid mechanics module in the process of carrying out finite element simulation on the scanning process in the step d; to simplify the model and save model computation time, the workpiece is defined as a rectangle 24 of 5mm x 4mm x 1 mm. The material property of the workpiece is defined as the corresponding material carried in a COMSOL material library, and the relevant property parameters of the optothermodynamics in the material property need to be corrected by adopting actual measurement values: vacuum thermal conductivity, thermal expansion coefficient, constant pressure specific heat capacity and density, all of which are parameters varying with temperature. The laser beam is defined as a moving heat source acting on the surface of a workpiece, the surface coating effect is realized by changing the emissivity of the boundary of the laser acting surface, the emissivity of the model surface without the black body coating is the actual emissivity of the material, and the emissivity with the black body coating is defined as 0.9. The whole workpiece is subjected to free tetrahedral meshing, the maximum size of the unit is 100 microns, and the minimum size of the unit is 30 microns. In order to improve the calculation precision, three-level subdivision grids are carried out on the laser scanning area. In the design, the energy distribution of the laser beam adopted in the research is Gaussian distribution, and in addition, the laser beam is not vertical to the surface of the workpiece in the experimental process, so that the actual laser spot area is an elliptical area. The field strength distribution equations in the X and Y directions in the gaussian distribution are:
in the above equation, c is the standard deviation of the distribution, r '/3, r ' is the minimum spot radius, r ' is 150 μm, assuming that the angle between the laser propagation direction and the workpiece surface is α, the gaussian distribution formula in the X direction is converted into:
the moving speed of the laser light source is vLThe expression for the gaussian distribution in the Y direction is:
therefore, the moving heat source power density equation of the laser moving heat source in the two-dimensional direction in the research can be expressed as follows:
Ixy＝P·qx·qy(7)
in the post-processing of the COMSOL software,and respectively solving the temperature peak value of the model and the Von-Mises stress distribution of the section of the laser spot. Comparing the temperature peak value with the phase change point and the melting point of the material, and considering that the laser heating causes the material to generate phase change when the phase change point of the material is less than the temperature peak value and less than the melting point of the material; in the Von-Mises stress profile, the thermal stress profile is compared to the breaking strength of the material when "thermal stress>Fracture strength ", it is believed that laser heating causes material fragmentation. Comparing the simulation result with the experimental result, optimizing the technological parameters of laser scanning, and obtaining the thermal influence depth d of the laserT。
The laser modified surface was cut away using a circular arc edge tool, as shown in fig. 6. In order to ensure that the cutter always cuts the laser modified material, the radius R of the tool tip of the arc blade turning tool is less than or equal to RT，RTRadius of curvature, R, of ablation cross sectionTObserving the shape of the ablation section by using an SEM and then fitting to obtain the shape; the cutting tool cannot exceed the laser modified layer in the cutting depth direction, so the back cutting amount dc＜dT(ii) a At the same time, whether laser modification leads to fragmentation of the denatured layer or structural change of the denatured layer should be distinguished, if the laser modification layer has obvious crack extension, the modified layer is cracked under the action of thermal stress, dcCan take a larger value without damaging the tool (d)c～dT) (ii) a If the modified section has no obvious cracks, observing the shape of the melting area or analyzing by using EDS (electron-beam diffraction) elements, wherein the oxygen-rich area of the section material is the modified area, and d is reduced as much as possiblecAnd gradually removing the modified cross section by multiple cutting (d)c＝dT/n；)。
In order to sufficiently remove the laser-modified material layer by cutting, the turning feed rate fc＜fTAccording to the parameters, the abrasion of the cutter can be reduced, the material removal efficiency is increased, and the surface cutting quality of the workpiece is improved.
The sixth specific implementation mode: the present embodiment is described with reference to fig. 1 to fig. 6, and in step b of the method for laser-assisted machining of a hard and brittle material by laser-modified ultra-precision cutting according to the present embodiment, according to the laser principle, the expression of the laser spot radius is as follows:
z in formula ①RThe length of the rayleigh band is represented,
represents the beam waist radius of the laser beam generated by the laser, and omega0Where ω (Z) denotes the laser spot radius, Z denotes the laser defocus amount, and λ denotes the laser center wavelength in equation ②.
The seventh embodiment: in the present embodiment, the laser pitting time on the surface of the workpiece in step b of the laser-assisted hard and brittle material processing method of laser-modified ultra-precision cutting according to the present embodiment is 1 second, which is described with reference to fig. 1 to 6.
The specific implementation mode is eight: the present embodiment is described with reference to fig. 1 to 6, and the step c of performing a laser scanning ablation experiment in the method for processing a hard and brittle material with the assistance of laser modified ultra-precision cutting laser according to the present embodiment to obtain three parameters, i.e., power, blackbody coating solution solubility, and defocus amount, includes:
firstly, regulating laser power and blackbody coating solution concentration in groups; the adjusting range of the laser power is 20W-100W, and the concentration of the blackbody coating solution is 10% -20%;
carrying out microscopic observation on each ablation point and measuring the area of an ablation area, and selecting power and coating concentration which have ablation traces and no obvious black body coating residual as reasonable parameters in the ablation area;
and thirdly, adjusting the displacement of a laser system through a five-axis displacement platform 3 to generate laser defocusing amount, wherein the numerical range of the defocusing amount is 0-45 mm, performing a grouped ablation experiment on the defocusing amount by using the laser power and the concentration parameter of the black body coating solution obtained in the previous step, observing and measuring an obtained ablation point, and selecting the defocusing amount parameter which has the largest ablation area, has the most obvious surface layer material ablation effect and does not have black body coating residue.
The specific implementation method nine: the present embodiment will be described with reference to fig. 1 to 6, and the method for laser-assisted machining of a hard and brittle material by laser-modified ultraprecise cutting according to the present embodiment is characterized in that: in the step d, the three parameters of the laser power, the blackbody coating solution concentration and the defocusing amount obtained in the step c are used for carrying out a dynamic scanning ablation process experiment on the surface of the workpiece by laser, and the laser scanning speed is obtained, wherein the formula of the laser scanning speed is as follows:
vc＝2δ·N③，
in the formula ③, N represents the spindle rotation speed of the ultra-precision machine tool 1, δ represents the laser ablation radius, vcIndicating the laser scanning speed.
Because various materials have different laser absorptivity, when certain ceramic materials with high infrared transmittance are processed, most laser energy can penetrate through the materials and cannot be focused on the surfaces of the materials, so that auxiliary processing is realized. In view of this, the present design is aided by an infrared blackbody coating 23 that can greatly improve the laser absorption efficiency. The blackbody coating has high absorptivity for infrared light, when laser irradiates the surface of the blackbody coating, only a small part of energy can be reflected or refracted, and most of energy is absorbed by the coating material and is converted into heat in a concentrated manner in a laser spot area. The coating material selected in the design is an organic black body paint pigment which is easy to dissolve in an organic solvent, the emissivity is as high as 0.9 +/-0.05, and the emissivity is the absorption efficiency of the material to light. The thickness of the blackbody coating plays an important role in laser ablation of the workpiece surface. And the main component of the black body coating is organic pigment which is very easy to dissolve in acetone, and the spraying thickness of the black body coating can be controlled by diluting the black body paint solution by using an acetone reagent and controlling the mass fraction ratio of the black body coating to the dissolved acetone.
Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (9)
1. A laser-modified ultra-precision cutting method for processing hard and brittle materials by aid of laser is characterized by comprising the following steps: the method for processing the hard and brittle material by the aid of the laser modified ultra-precision cutting comprises the following specific steps:
step one, building a laser auxiliary cutting platform;
focusing the continuous laser beam generated by the laser output head on the surface of the workpiece;
and step three, cutting the modified workpiece surface by using a cutter (2).
2. The method for laser-assisted machining of the hard and brittle material through laser-modified ultra-precision cutting according to claim 1, characterized by comprising the following steps: the laser auxiliary cutting platform in the first step comprises a five-axis manual displacement platform (3) and a laser processing module (4), wherein the laser processing module (4) is installed on the five-axis manual displacement platform (3);
the steps of building the laser auxiliary cutting platform are as follows:
a, mounting a laser processing module (4) on a five-axis displacement platform (3);
b, mounting the five-axis displacement platform (3) on the ultra-precision machine tool (1);
and step C, mounting the cutter (2) on the ultra-precision machine tool (1).
3. The method for laser-assisted machining of the hard and brittle material through laser-modified ultra-precision cutting according to claim 2, characterized by comprising the following steps: the five-axis manual displacement platform (3) comprises a vertical Y-direction manual displacement platform (16), a connecting rib plate (17), a rotary R-direction manual displacement platform (18), a linear Z-direction manual displacement platform (19), a linear X-direction manual displacement platform (20) and a linear W-direction manual displacement platform (21); the laser processing module (4) is installed on the manual displacement platform (21) in the direction of straight line W, the manual displacement platform (21) in the direction of straight line W is installed on the manual displacement platform (16) in the direction of vertical Y, the manual displacement platform (16) in the direction of vertical Y is connected with the manual displacement platform (18) in the direction of rotation R through a connecting rib plate (17), the manual displacement platform (18) in the direction of rotation R is installed on the manual displacement platform (19) in the direction of straight line Z, and the manual displacement platform (19) in the direction of straight line Z is installed on the manual displacement platform (20) in the direction of straight line X.
4. The laser-modified ultra-precision-machined laser-assisted hard and brittle material processing method as claimed in claim 2 or 3, characterized in that: the laser processing module (4) comprises a protective window glass (5), a converging mirror system (6), a collimating mirror system (7), a laser fiber (8), a water-cooling joint (9), a rear protective plate (10), a laser QBH output head (11), a base plate (12), a protective cover (13) and a front protective plate (14); protection window glass (5), convergent mirror system (6), collimating mirror system (7) are connected gradually by preceding to back end to end, protection window glass (5), convergent mirror system (6), collimating mirror system (7) is installed in protection casing (13) by preceding to back in proper order, collimating mirror system (7) are connected with laser fiber (8) through laser instrument QBH delivery head (11), the front end in protection casing (13) is installed in preceding protection shield (14), the rear end in protection casing (13) is installed in rear protection shield (10), water-cooling connects (9) and installs on rear protection shield (10).
5. The method for laser-assisted machining of the hard and brittle material through laser-modified ultra-precision cutting according to claim 1, characterized by comprising the following steps: in the second step, the specific steps of focusing the continuous laser beam generated by the laser output head on the surface of the workpiece are as follows:
a, adjusting the position of a laser spot of a laser processing module (4) on the surface of a workpiece through a five-axis displacement platform (3);
b, adjusting and determining the radius of the laser spot;
adjusting laser to focus on the surface of the workpiece, wherein the defocusing amount Z of the laser is 0; when Z is equal to Z+>When the concentration is 0 or less than 0,the laser is in a defocusing state; when the laser generates defocusing amount, the laser spot becomes large;
c, performing a laser scanning ablation experiment to obtain three parameters of power, blackbody coating solution solubility and defocusing amount;
step d, carrying out grouping ablation research on different laser scanning speeds;
e, performing finite element simulation on the scanning process in the step d by using COMSOL software;
step f, respectively solving the temperature peak value of the model and the stress distribution of the section of the laser spot in COMSOL software processing;
and g, determining laser parameters.
6. The method for laser-assisted machining of the hard and brittle material through laser-modified ultra-precision cutting according to claim 5, characterized by comprising the following steps: in the step b, according to the laser principle, the laser spot radius expression is as follows:
z in formula ①RThe length of the rayleigh band is represented,
represents the beam waist radius of the laser beam generated by the laser, and omega0Where ω (Z) denotes the laser spot radius, Z denotes the laser defocus amount, and λ denotes the laser center wavelength in equation ②.
7. The method for laser-assisted machining of the hard and brittle material through laser-modified ultra-precision cutting according to claim 5, characterized by comprising the following steps: and b, pitting corrosion time of the laser on the surface of the workpiece in the step b is 1 second.
8. The method for laser-assisted machining of the hard and brittle material through laser-modified ultra-precision cutting according to claim 5, characterized by comprising the following steps: and c, performing a laser scanning ablation experiment to obtain three parameters of power, blackbody coating solution solubility and defocusing amount:
firstly, regulating laser power and blackbody coating solution concentration in groups; the adjusting range of the laser power is 20W-100W, and the concentration of the blackbody coating solution is 10% -20%;
carrying out microscopic observation on each ablation point and measuring the area of an ablation area, and selecting power and coating concentration which have ablation traces and no obvious black body coating residual as reasonable parameters in the ablation area;
and thirdly, adjusting the displacement of a laser system through a five-axis displacement platform (3) to generate laser defocusing amount, wherein the numerical range of the defocusing amount is 0-45 mm, performing a grouped ablation experiment on the defocusing amount by using the laser power and the concentration parameter of the black body coating solution obtained in the previous step, observing and measuring an obtained ablation point, and selecting the defocusing amount parameter which has the largest ablation area, has the most obvious surface layer material ablation effect and does not have black body coating residue.
9. The method for laser-assisted machining of the hard and brittle material through laser-modified ultra-precision cutting according to claim 5, characterized by comprising the following steps: in the step d, the three parameters of the laser power, the blackbody coating solution concentration and the defocusing amount obtained in the step c are used for carrying out a dynamic scanning ablation process experiment on the surface of the workpiece by laser, and the laser scanning speed is obtained, wherein the formula of the laser scanning speed is as follows:
vc＝2δ·N③，
in the formula ③, N represents the spindle rotation speed of the ultra-precision machine tool (1), delta represents the laser ablation radius, and vcIndicating the laser scanning speed.
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