Multi-axis laser superfinishing method and apparatus

Abstract

The application is suitable for the technical field of laser precision machining, and provides a multi-axis linkage laser superfinishing method and equipment. The method comprises the following steps: determining a first laser track and a second laser track according to the processing requirements of micro-nano texture processing or hard and brittle material polishing; performing red-ultraviolet double-beam ultrafast laser layer-by-layer removal processing on a target surface by using a first laser moving along the first laser track and a second laser moving along the second laser track, to obtain a polished hard and brittle material workpiece or a workpiece after micro-nano texture processing; the application utilizes red-ultraviolet double-beam ultrafast laser layer-by-layer removal processing, is compatible with laser precision polishing and micro-nano texture processing of high brittle and hard materials, overcomes the problem of insufficient processing precision in the prior art by means of infrared laser preheating and rough processing and ultraviolet laser cold processing, and realizes superfinishing; in addition, the texture processing part can realize controllable texture processing with less distortion by parameterized surface mapping and gradient field encoding to solve Poisson equation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of laser processing, and particularly relates to a multi-axis linkage laser superfinishing method and device. BACKGROUND

[0002] Such as ceramics, optical lenses, sapphire, third-generation semiconductor SiC ceramic substrates, etc., are widely used in 5G communication, aerospace, semiconductors, mechanical manufacturing, smart phones and other national defense and civilian fields.

[0003] Cutting tools are the teeth of industry. With the advent of the 5G era, hard and brittle parts represented by graphite, ceramics, optical glass, sapphire, etc. are increasingly widely used, and processing requirements continue to improve. New materials, new products and new demands force cutting tools to be super-hardened and profiled. The market is in great demand for gradient ceramic material passivation polishing technology and process of milling cutters.

[0004] 3D curved surfaces of consumer electronics, home and industrial products can be precisely machined with various three-dimensional textures, beautifying the appearance of the product and making the product appear as a high-end product. Texture can beautify the product, prevent surface scratches, and have anti-slip effects.

[0005] 5G technology leads to the advent of the new era of information, and high brittle and hard material parts represented by synthetic diamond, ceramics, optical glass, sapphire, etc. are increasingly widely used, and processing requirements continue to improve. The demand is very strong for surface polishing of such parts. The precision polishing (polishing here can be understood as processing the surface of the workpiece into a specific texture structure) of high brittle and hard material parts is essentially a superfinishing technology.

[0006] Existing plane texture mapping technology usually only targets image texture. Since an image is a two-dimensional plane without "height", once parameterization is established, texture coordinates can be interpolated on a curved surface to synthesize a curved surface texture. However, for three-dimensional geometric three-dimensional texture, it is difficult to directly synthesize "geometric details". The method provided by the prior art has problems such as difficulty in realizing seamless texture mapping of the entire curved surface, and / or large deformation (texture distortion details), as shown in Figure 5 .

[0007] Therefore, how to provide a laser micro-nano texture processing method and device with overall seamless and small deformation has become a technical problem that needs to be solved in the industry. SUMMARY

[0008] Embodiments of the present application provide a multi-axis linkage laser superfinishing method and device, which can solve the problems of difficulty in seamless texture mapping of the entire curved surface and large deformation.

[0009] In a first aspect, embodiments of the present application provide a multi-axis linkage laser superfinishing method, comprising:

[0010] The method for micro-nano stereotexture precision machining and super-precision polishing of hard and brittle materials determines that the machining requirement is micro-nano texture machining, and then:

[0011] Obtaining a geometric texture and a target surface; the target surface refers to a surface of a set region on a workpiece to be machined as a target texture; the target texture is a three-dimensional texture corresponding to the geometric texture based on the geometric texture; and the target texture includes micro-nano stereotexture machining texture.

[0012] Extracting texture information in the geometric texture and performing gradient coding to obtain texture gradient information;

[0013] Parameterizing the geometric texture and surface information in the target surface and establishing a surface mapping relationship of the geometric stereotexture to the target surface;

[0014] Solving a Poisson equation according to the surface mapping relationship and the texture gradient information to obtain a Poisson reconstruction result as a machining target structure, and determining a first laser track of a first laser and a second laser track of a second laser based on the machining target structure;

[0015] Determining that the machining requirement is polishing of a hard and brittle material workpiece, and then:

[0016] Obtaining a polished surface as a machining target structure according to material parameters of the workpiece and a microstructure of the workpiece on the target surface;

[0017] Determining a first laser track of a first laser and a second laser track of a second laser according to the machining target structure; the first laser is an infrared laser; the second laser is an ultraviolet laser; the power of the first laser is greater than that of the second laser; and the shortest pulse duration of the second laser is femtosecond or picosecond.

[0018] In a possible implementation manner of the first aspect, the step of parameterizing the geometric texture and the surface information in the target surface and establishing a surface mapping relationship of the geometric texture to the target surface includes:

[0019] Extracting surface information in the geometric texture and parameterizing to obtain a basic surface parameter domain;

[0020] Global parameterizing the target surface to obtain a target surface parameter domain;

[0021] Determining a corresponding relationship of a surface boundary and a vertex as a boundary constraint according to the basic surface parameter domain and the target surface parameter domain;

[0022] Under the constraint of the boundary, a local transformation from any region in the base surface parameter domain to a corresponding region in the target surface parameter domain is determined; the local transformation comprises a rotation transformation and / or a scale transformation; a set of local transformations from at least part of the surface in the base surface parameter domain to at least part of the surface in the target surface parameter domain constitutes the surface mapping relationship;

[0023] The step of solving a Poisson equation according to the surface mapping relationship and the texture gradient information to obtain a Poisson reconstruction result comprises:

[0024] Under the constraint of the surface mapping relationship, the texture gradient information is integrated by using the Poisson equation to obtain gradient information under the target surface as the Poisson reconstruction result.

[0025] In a possible implementation manner of the first aspect, the target surface is composed of a constraint region and a non-constraint region; the constraint region refers to a region in which the rotation transformation and / or the scale transformation of the set local transformation satisfies a preset twist parameter;

[0026] The step of solving a Poisson equation according to the surface mapping relationship and the texture gradient information to obtain a Poisson reconstruction result comprises:

[0027] Under the constraint of the surface mapping relationship and the twist parameter corresponding to the constraint region, the volumetric texture gradient information is integrated by using the Poisson equation to obtain gradient information under the target surface as the Poisson reconstruction result.

[0028] In a possible implementation manner of the first aspect, the volumetric texture is a micro-nano structure, and a distortion rate of the mapping on the surface is less than 5%; and a geometric texture after the extraction and mapping is generated, so as to become a planning object of a laser beam machining track; low deformation control, boundary texture processing, texture extension, algorithm efficiency, algorithm robustness, rendering and an interactive interface;

[0029] After the texture is mapped on the surface, a plurality of laser machining tracks can be generated, and the volumetric texture is formed through subtractive manufacturing.

[0030] In a possible implementation manner of the first aspect, the hard and brittle material ultra-precision polishing method is a double laser beam precision polishing method for high brittle and hard materials; an infrared pulse laser preheats a surface of a part to an optimized temperature below a melting point, and improves a multi-photon absorption rate of the material; first, the surface of the high brittle and hard material part is preheated to the optimized temperature, and the multi-photon absorption rate of the material is greatly improved; most of local wave peaks are cut off through cold processing, and only a small number of wave peaks are gasified through hot processing; therefore, various defects caused by the hot processing are greatly reduced, and cold processing is mainly used for polishing, so that the precision polishing of the high brittle and hard material is realized.

[0031] In a possible implementation manner of the first aspect, the hard and brittle material refers to any one or a combination of photovoltaic silicon material, semiconductor silicon material, sapphire material, magnetic material, optical glass, and ceramic material; the polished semiconductor SiC ceramic substrate is cold processed, thermal effect is greatly reduced, semi-finishing polishing of the SiC ceramic substrate can be performed, polishing time is greatly saved, and overall polishing efficiency of the SiC ceramic substrate is greatly improved.

[0032] In a possible implementation manner of the first aspect, the double-laser-beam processing includes that the first laser is an infrared laser, the second laser is an ultraviolet laser, the power of the first laser is greater than that of the second laser, and the shortest pulse duration of the second laser is femtosecond or picosecond.

[0033] The first laser track and the second laser track are both multi-axis linkage tracks, and the multi-axis linkage refers to that the workpiece, the first laser source for emitting the first laser, and the second laser source for emitting the second laser all have three translational degrees of freedom and at least two rotational degrees of freedom.

[0034] In a possible implementation manner of the first aspect, the double-laser-beam processing includes that the first laser track and the second laser track are both tracks obtained by optimization under function constraints; the function constraints refer to that the first laser is used to heat a current processing layer to a preset temperature and perform preliminary processing, and the second laser source is used to perform secondary cold processing on the current processing layer at the preset temperature; the cold processing refers to laser processing that utilizes high-energy photons to separate at least part of molecules on the current processing layer from a material body without generating additional heat.

[0035] The target curved surface is processed by using the first laser moving along the first laser track and the second laser moving along the second laser track to obtain a polished hard and brittle material workpiece or a workpiece processed by micro-nano texturing.

[0036] In a possible implementation manner of the first aspect, the double-laser-beam processing includes that the first laser track and the second laser track are both multi-axis linkage tracks; the multi-axis linkage refers to that the workpiece, the first laser source for emitting the first laser, and the second laser source for emitting the second laser all have three translational degrees of freedom and at least two rotational degrees of freedom.

[0037] The first laser track and the second laser track are tracks optimized under functional constraints; the functional constraints refer to that the first laser is used to heat a current processing layer to a preset temperature and perform preliminary processing; the second laser emitted by the second laser source is used to perform secondary cold processing on the current processing layer at the preset temperature; the cold processing refers to laser processing that utilizes high-energy photons to separate at least part of molecules on the current processing layer from a material body without generating additional heat.

[0038] In a second aspect, the embodiments of the present application provide a multi-axis linkage laser superfinishing device, which can be used to perform the multi-axis linkage laser superfinishing method in any of the first aspect, and comprises:

[0039] A turntable is used to fix the workpiece and can drive the workpiece to rotate around the x, y or z axis as the rotation axis under a preset Cartesian coordinate system;

[0040] A moving guide rail mechanically connected with the turntable is used to drive the turntable and the workpiece fixed on the turntable to move along the x, y or z axis direction under a preset Cartesian coordinate system;

[0041] A first laser source is used to emit first laser to the workpiece at a preset first frequency, first pulse width and first power to perform processing and / or preheating;

[0042] A first moving mechanism mechanically connected with the first laser source is used to drive the first laser source to rotate around the x, y or z axis as the rotation axis under a preset Cartesian coordinate system, and / or move along the x, y or z axis direction under a preset Cartesian coordinate system;

[0043] A second laser source is used to emit second laser to the workpiece at a preset second frequency, second pulse width and second power to perform processing;

[0044] A second moving mechanism mechanically connected with the second laser source is used to drive the second laser source to rotate around the x, y or z axis as the rotation axis under a preset Cartesian coordinate system, and / or move along the x, y or z axis direction under a preset Cartesian coordinate system;

[0045] Under the driving of the first moving mechanism and the second moving mechanism, the first laser source and the second laser source can move or rotate independently of the turntable.

[0046] The present application has the following beneficial effects:

[0047] The red ultraviolet dual laser beam ultrafast laser layer-by-layer removal processing can be compatible with laser precision polishing and micro-nano texture processing of high brittle hard materials, the infrared laser preheating and rough processing and the ultraviolet laser cold processing can overcome the problem of insufficient processing precision in the prior art, and ultra-precision processing is realized; in addition, the texture processing part can realize distortionless and controllable texture processing through parameterized curved surface mapping and gradient field encoding to solve Poisson equation. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0049] Figure 1 is a flowchart of the multi-axis linkage laser ultra-precision machining method provided by the embodiments of the present application;

[0050] Figure 2 is a structural schematic diagram of the multi-axis linkage laser ultra-precision machining device provided by the embodiments of the present application;

[0051] Figure 3 the (a) diagram in is a structural schematic diagram of a machined surface provided by the embodiments of the present application;

[0052] Figure 3 the (b) diagram in is a structural schematic diagram of layer-by-layer processing of a machined surface provided by the embodiments of the present application;

[0053] Figure 4 the (a) diagram in is a schematic diagram of three-dimensional texture processing effect provided by the embodiments of the present application;

[0054] Figure 4 the (b) diagram in is a schematic diagram of three-dimensional texture processing scale provided by the embodiments of the present application;

[0055] Figure 4 the (c) diagram in is a schematic diagram of three-dimensional texture processing details provided by the embodiments of the present application;

[0056] Figure 5 is a schematic diagram of the texture mapping distortion problem in the prior art;

[0057] Figure 6 is a flowchart of the three-dimensional texture mapping method provided by the embodiments of the present application;

[0058] Figure 7 is a schematic diagram of a texture mapping task performed by the method of an embodiment of the present application;

[0059] Figure 8 is a schematic diagram of layered processing provided by an embodiment of the present application.

[0060] Reference signs:

[0061] First mechanical arm 2011;

[0062] First beam expander 2012;

[0063] First focusing mirror 2013;

[0064] Second mechanical arm 2021;

[0065] Second beam expander 2022;

[0066] Second focusing mirror 2023;

[0067] Rotary table 203;

[0068] Sealed cavity 204. DETAILED DESCRIPTION

[0069] In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, technologies, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

[0070] It is to be understood that the terminology "includes", "has", "holds", "contains" and / or "comprising", when used in this specification and in the following claims, indicates the presence of the described features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0071] It is also to be understood that the terminology "and / or" when used in this specification and in the following claims, refers to at least one of the items, or any combination of one or more of the items, and includes any possible combination of the items.

[0072] As used in this specification and in the claims, the terms "if" and "when" can be interpreted to mean "upon" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [a described condition or event] is detected" can be interpreted to mean "upon determining" or "in response to determining" or "upon detecting [a described condition or event]" or "in response to detecting [a described condition or event]", depending on the context.

[0073] In addition, in the description of the present application and the appended claims, the terms "first", "second", "third", etc. are used only to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0074] In the present application, the reference to "one embodiment" or "some embodiments" means that the specific features, structures or characteristics described in connection with the embodiment are included in one or more embodiments of the present application. Therefore, the statements "in one embodiment", "in some embodiments", "in other some embodiments", "in further some embodiments" and the like appearing in the present specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "include", "contain", "have" and their variants mean "including but not limited to", unless otherwise specifically emphasized.

[0075] The embodiments of the present application provide a multi-axis linkage laser superfinishing method, as shown in the accompanying drawings, comprising: Figure 1 a micro-nano three-dimensional texture precision machining and a hard and brittle material super-precision polishing method;

[0076] Step 1022, determining that the machining requirement is micro-nano texture machining, then:

[0077] Obtaining a geometric texture and a target surface; the target surface refers to the surface of the set region on the workpiece to be machined as a target texture; the target texture is a three-dimensional texture corresponding to the geometric texture based on the geometric texture; the target texture includes micro-nano three-dimensional machining texture;

[0078] Step 1024, extracting texture information in the geometric texture and performing gradient coding to obtain texture gradient information;

[0079] Step 1026, parameterizing the geometric texture and the surface information in the target surface, and establishing a surface mapping relationship of the geometric three-dimensional texture to the target surface;

[0080] Step 1028, solving a Poisson equation according to the surface mapping relationship and the texture gradient information to obtain a Poisson reconstruction result as a machining target structure, and determining a first laser trajectory of a first laser and a second laser trajectory of a second laser based on the machining target structure;

[0081] Step 1042, determining that the machining requirement is hard and brittle material workpiece polishing, then:

[0082] According to the material parameters of the workpiece and the microstructure of the workpiece on the target surface, obtaining a polished surface as a machining target structure;

[0083] At step 1044, a first laser trajectory of the first laser and a second laser trajectory of the second laser are determined according to the machining target structure; the first laser is an infrared laser; the second laser is an ultraviolet laser; the power of the first laser is greater than that of the second laser; and the shortest pulse duration of the second laser is in the order of femtoseconds or picoseconds.

[0084] At step 106, multi-axis linkage laser superfinishing is performed.

[0085] In an optional embodiment, the micro-nano scale limit is defined based on micro-nano manufacturing technology, which refers to the design, machining, assembly, integration and application technology of parts with millimeter, micrometer and nanometer scales and components or systems composed of these parts.

[0086] The essence of polishing is to smooth the micro-topography of the part surface, so that the surface roughness is reduced to a certain extent. From the perspective of 3D micro-topography, the part surface is composed of "undulating" peaks and valleys. The current mainstream automatic polishing process adopts micro-subtractive manufacturing technology, which removes the peaks and even eliminates the valleys to reduce the surface roughness. Common polishing processes include magnetic abrasive finishing, mechanical polishing, ultrasonic polishing, wheel polishing, electrolytic polishing, fluid polishing and chemical polishing, etc.

[0087] The above common polishing processes all have some common or specific defects when machining high brittle-hard material parts. A common problem is the pollution of the machining environment. Because the mechanical movement of abrasive particles, chemical or electrolytic corrosion and other micro-subtractive methods remove the peaks of the micro-topography, a large amount of harmful residual powder or chemical residue is inevitably generated, and the polishing site of many small and micro enterprises is not acceptable. The above common polishing processes also have specific defects related to machining efficiency, polishing consistency and shape limitation of polished workpieces.

[0088] By way of example and not limitation, the present embodiment can be applied to the following scenarios:

[0089] 1. It is suitable for automatically generating polishing workstations and automated production lines for water hardware, medical devices, sports equipment, automobiles and other industries;

[0090] 2. It can automatically polish and further apply in combination with robot vision and other applications;

[0091] 3. It can be designed for non-standard products according to customer requirements;

[0092] Specifically, taking robot polishing as an example, the present embodiment:

[0093] 1. It can provide one-stop automatic production lines from rough grinding to fine grinding;

[0094] 2. Automatic grinding can control the grinding weight, thickness and appearance shape;

[0095] 3. The programming path can automatically generate the grinding path offline;

[0096] 4. It can be matched with the precise positioning sensor system to cooperate with the mechanical arm and be popularized in the market.

[0097] It is worth noting that in the embodiment, the geometric texture can be a three-dimensional geometric texture or a two-dimensional geometric texture.

[0098] For a three-dimensional geometric texture, the surface information and gradient information in the geometric texture can be directly extracted.

[0099] For a two-dimensional geometric texture, the gradient field needs to be constructed for the non-surface information (such as color / depth data) of the geometric texture, and then the texture gradient information is extracted.

[0100] The embodiment has the following beneficial effects:

[0101] The red and ultraviolet dual-laser beam ultrafast laser layer-by-layer removal processing can be compatible with laser precision polishing and micro-nano texture processing of high brittle hard materials. Through the means of infrared laser preheating and rough processing and ultraviolet laser cold processing, the problem of insufficient processing precision in the prior art is overcome, and ultra-precision processing is realized. In addition, the texture processing part can realize distortion-controllable texture processing through parameterized surface mapping and gradient field encoding to solve the Poisson equation.

[0102] According to the above embodiment, in the embodiment:

[0103] The step of parameterizing the surface information in the geometric texture and the target surface and establishing the surface mapping relationship from the geometric texture to the target surface comprises:

[0104] Extracting the surface information in the geometric texture and parameterizing it to obtain a basic surface parameter domain;

[0105] Global parameterizing the target surface to obtain a target surface parameter domain;

[0106] Determining the corresponding relationship of the surface boundary and the vertex according to the basic surface parameter domain and the target surface parameter domain as a boundary constraint;

[0107] Under the boundary constraint, determine the local transformation from any region in the basic surface parameter domain to the corresponding region in the target surface parameter domain; the local transformation comprises a rotation transformation and / or a scale transformation; the set of local transformations from at least a part of the surface in the basic surface parameter domain to at least a part of the surface in the target surface parameter domain constitutes the surface mapping relationship;

[0108] The step of solving a Poisson equation according to the curved surface mapping relationship and the texture gradient information to obtain a Poisson reconstruction result comprises:

[0109] Under the constraint of the curved surface mapping relationship, the texture gradient information is integrated by using the Poisson equation to obtain gradient information under the target curved surface as the Poisson reconstruction result.

[0110] By way of example and not limitation, the curved surface boundary and vertex can refer to the boundary and vertex of the whole of the curved surface corresponding to the target curved surface / geometry texture pair, or the boundary and vertex of any region.

[0111] For the latter, the partitions of the curved surface corresponding to the target curved surface and the geometry texture should be one-to-one corresponding, and naturally, the number of the partitions of the curved surface corresponding to the target curved surface and the geometry texture is also the same.

[0112] Considering the i-th partition in the target curved surface, i.e., the i-th region, and the j-th partition of the curved surface corresponding to the geometry texture, i.e., the j-th region, the one-to-one correspondence between the two is realized based on the constraint of the boundary and vertex (i.e., the boundary constraint). Under the boundary constraint, the local transformation from the i-th partition in the target curved surface to the j-th partition of the curved surface corresponding to the geometry texture is strictly corresponding, the error of the Poisson equation at the boundary is zero, and the adjacent and continuously one-to-one corresponding target curved surface partitions and the curved surface partitions corresponding to the geometry texture naturally have overlapping boundaries and vertices, so the geometry of these local transformations is also continuous and smooth, which can effectively guarantee the seamless of the Poisson reconstruction result.

[0113] The embodiment maps the designed three-dimensional geometry solid texture to the surface of the target three-dimensional model, so as to reconstruct the texture details as faithfully as possible, and extracts the mapped geometry texture on the target model to make it the planning object of the laser beam machining track. For this purpose, the project will focus on overcoming Figure 5 the defects such as large deformation and distortion of the mapped texture, and proposes a low deformation variable and seamless three-dimensional geometry texture mapping technology based on global parameterization: the three-dimensional geometry solid texture is decomposed into a basic curved surface and texture details, the three-dimensional texture details are encoded by using a geometry gradient field, the corresponding relationship between the target curved surface and the basic curved surface is established based on the global parameterization method, the rotation field and the scale field are reconstructed through the normal information and the geometry deformation error of the two, and finally the geometry texture is reconstructed on the target curved surface through the Poisson equation, so as to control the texture distortion rate within 5% in the case of low Gaussian curvature. The technical method of the texture mapping process proposed in the embodiment is shown in Figure 6 .

[0114] Through the method of the embodiment, as shown in Figure 7 , the three-dimensional texture designed on the plane is mapped on the target curved surface model shown, and the three-dimensional texture after mapping on the target curved surface without distortion can be obtained.

[0115] The beneficial effects of the embodiment are that:

[0116] By determining the local transformation for each region under the boundary constraint and merging the set of local transformations into the surface mapping relationship, the complexity of the calculation can be reduced and the efficiency can be improved under the premise of ensuring overall seamless.

[0117] By integrating the texture gradient information using the Poisson equation under the constraint of the surface mapping relationship, a Poisson reconstruction result with zero error at the boundary and the vertex can be obtained, which does not have a false boundary box, and the target texture quality of the workpiece surface obtained by laser micro-nano texture processing based on the Poisson reconstruction result is higher.

[0118] According to any of the above embodiments, in the present embodiment:

[0119] The target surface is composed of a constraint region and a non-constraint region; the constraint region refers to a region in which the rotation transformation and / or scale transformation of the set local transformation meets the preset twist parameter;

[0120] The step of solving the Poisson equation according to the surface mapping relationship and the texture gradient information to obtain the Poisson reconstruction result comprises:

[0121] Under the constraint of the surface mapping relationship and the twist parameter corresponding to the constraint region, the Poisson equation is used to integrate the three-dimensional texture gradient information to obtain the gradient information under the target surface as the Poisson reconstruction result.

[0122] In an optional implementation, the constraint of the twist parameter can also be implemented in the parameterization stage, i.e., the step of parameterizing the surface information in the geometric texture and the target surface and establishing the surface mapping relationship from the geometric texture to the target surface. By using different parameterization models for the constraint region and the non-constraint region in the parameterization process, the mapping process of the parameter domain naturally meets the twist parameter limit of the constraint region, which is also a feasible scheme.

[0123] Texture mapping technique is an important research direction of computer graphics, widely used in computer graphics and image processing field, but rarely used in industrial manufacturing field. Unlike the general texture mapping technique which emphasizes color and gray rendering features, the texture mapping technique for five-axis NC laser processing focuses on accurately "sticking" the shape of the planar texture to the specified location of the three-dimensional surface of the processed part according to the specified size ratio, angle and orientation. To achieve this purpose, the parameterization of the three-dimensional surface of the processed part is the key to the texture mapping technique. Based on the research of the length-preserving parameterization algorithm in the parameterization process of texture mapping, and aiming at the specific application requirements of laser processing, the embodiment has the following characteristics and beneficial effects:

[0124] 1) The parameterization method can flexibly adjust the position, orientation and size of the pattern on the surface according to the needs, instead of completely mapping with the minimum distortion;

[0125] 2) The distortion distribution of the parameterization takes into account the specific content of the texture pattern, and tries to minimize the distortion at important positions, instead of completely uniformly distributing the distortion;

[0126] 3) The result of the parameterization needs to be further converted into the geometric model required by laser processing, instead of only remaining in the form of mapping function.

[0127] The embodiment discusses the numerical method for solving the parameterization of the texture mapping of the three-dimensional surface for five-axis NC laser processing, which can constrain and control the position, size and orientation of the texture mapping, and reduce the deformation degree of the three-dimensional texture in the effective laser processing area. The texture mapping technique can enable the laser processing equipment based on the five-axis NC laser processing system to complete the mold cavity texture processing function. The vector graph surface mapping numerical method fully considers the characteristics of the vector graph, and proposes an adaptive vector graph discretization numerical method to meet the requirements of precision and display speed for laser processing.

[0128] The key to clearly and continuously etching the specified texture on the three-dimensional surface of the mold by the three-dimensional galvanometer laser is to establish a three-dimensional texture mathematical vector model of the three-dimensional surface of the mold. The establishment process of the mathematical model is as follows: (1) design a two-dimensional planar texture (bitmap or vector graph format); (2) determine the three-dimensional cavity model of the mold to be etched; (3) map the two-dimensional planar texture to the surface of the three-dimensional cavity of the mold through a specific algorithm; (4) remove the original model, and the remaining three-dimensional texture mathematical vector model for laser processing is obtained. The three-dimensional galvanometer laser system processing software can read the three-dimensional texture vector and convert it into a galvanometer scanning path coordinate to perform three-dimensional processing of the texture.

[0129] Figure 4is the actual effect of laser processing texture. The Area A is close to the plane, the processing shape of the hexagon is very accurate naturally, while the Area B is the area with very large Gaussian curvature, the distortion of texture mapping and processing is relatively large, but through the comparison of the scanning data, the detection data of the distortion degree can be obtained. Figure 4 The actual distortion rate of the Area B region is only 2.3%.

[0130] One of the cores of the embodiment is the parameterized low deformation variable three-dimensional texture mapping method. Based on the global parameterized low deformation variable and seamless three-dimensional geometric texture mapping method, the control optimization of the texture mapping position and size based on the characteristics of the three-dimensional curved surface model is realized, and the distortion rate of the texture after the Gaussian surface mapping can be controlled to be less than 5%.

[0131] The embodiment has the following beneficial effects:

[0132] By introducing the constraint region and the non-constraint region, the integral process of the Poisson equation is no longer strictly divided into distortion, but provides more strict parameter requirements for the key region of interest, i.e., the constraint region, and averages the texture distortion caused by the curved surface shape in other non-constraint regions, so that a more customized Poisson reconstruction result is obtained. Based on the Poisson reconstruction result, additional constraints can be performed on the key region of the workpiece surface, such as the region with large Gaussian curvature, to obtain a target texture with higher quality.

[0133] According to any one of the above embodiments, in the embodiment:

[0134] The three-dimensional texture is a micro-nano structure, the distortion rate of the mapping on the curved surface is less than 5%, and the geometric texture after the shell extraction mapping is generated to become the planning object of the laser beam processing track; low deformation variable control, boundary texture processing, texture extension, algorithm efficiency, algorithm robustness, rendering and interactive interface;

[0135] After the texture mapping on the curved surface, a plurality of laser processing tracks can be generated to form a three-dimensional texture through subtractive manufacturing.

[0136] In the embodiment, the three-dimensional texture can be a macroscopic structure or a micro-nano structure, the distortion rate of the mapping on the curved surface is less than 5%, and the geometric texture after the shell extraction mapping is generated to become the planning object of the laser beam processing track.

[0137] The execution of the embodiment can be based on the program software corresponding to the method. After the software mapping, the three-dimensional texture can be removed through the layer-by-layer processing track according to the planning object, and the structure of the three-dimensional texture is reserved. The three-dimensional texture processing method is to divide the texture into layers by using the software, and the generated DXF file is the scanning path for laser processing. Through the layer-by-layer scanning of the laser, the laser texture subtractive manufacturing is realized.

[0138] The beneficial effects of the present embodiment are that:

[0139] As shown in the figure, by means of layered processing, the processing of the target texture can be more finely realized, and a better quality target texture can be obtained. Figure 8

[0140] According to any of the above embodiments, in the present embodiment:

[0141] The hard and brittle material ultra-precision polishing method is a double laser beam precision polishing method for high brittle and hard materials. The infrared pulse laser preheats the surface of the part to an optimal temperature below the melting point, and improves the ultraviolet laser multi-photon absorption rate of the material. First, the surface of the high brittle and hard material part is preheated to an optimal temperature, and the absorption rate of the material to the multi-photon is greatly improved. Most of the local peaks are cut off by "cold processing", and only a few are gasified by "hot processing". Therefore, the various defects caused by "hot processing" are greatly reduced, and the polishing is mainly completed by cold processing, thereby realizing the precision polishing of high brittle and hard materials.

[0142] Specifically, the double laser beam processing, the first laser is an infrared laser; the second laser is an ultraviolet laser; the power of the first laser is greater than that of the second laser; the shortest pulse duration of the second laser is femtosecond or picosecond;

[0143] The first laser track and the second laser track are both multi-axis linkage tracks; the multi-axis linkage means that the workpiece, the first laser source emitting the first laser, and the second laser source emitting the second laser all have three translational degrees of freedom and at least two rotational degrees of freedom.

[0144] The first laser track and the second laser track of the double laser are both tracks obtained by optimization under functional constraints; the functional constraints mean that the first laser is used to heat the current processing layer to a preset temperature and perform preliminary processing; the second laser source emits a second laser for performing secondary cold processing on the current processing layer at the preset temperature; the cold processing means that at least a part of the molecules on the current processing layer are separated from the material body by using high-energy photons, and the laser processing does not generate additional heat;

[0145] The first laser moving along the first laser track and the second laser moving along the second laser track are used to perform red-ultraviolet double-beam ultrafast laser layer-by-layer removal processing on the target surface to obtain a polished hard and brittle material workpiece, or a workpiece after micro-nano texture processing.

[0146] ​The first laser beam and the second laser beam are both multi-axis linkage tracks; the multi-axis linkage means that the workpiece, the first laser source and the second laser source all have three degrees of translational freedom and at least two degrees of rotational freedom;

[0147] The first laser beam and the second laser beam are both tracks optimized under functional constraints; the functional constraints mean that the first laser beam is used to heat the current processing layer to a preset temperature and perform preliminary processing; the second laser source is used to perform secondary cold processing on the current processing layer at the preset temperature; the cold processing means that at least a part of molecules on the current processing layer are separated from the material body by using high-energy photons, and the laser processing does not generate additional heat.

[0148] The precision polishing of high brittle-hard materials, the passivation polishing of ceramic coated tools, and the micro-nano texture (including micro-nano texture) processing of mold cavities and product surfaces all belong to super finishing, which is the bottleneck of current laser precision machining. To overcome this bottleneck, it is necessary to greatly increase the proportion of "cold processing" in the "hot" and "cold" mixed mode processing.

[0149] The infrared pulse ultraviolet picosecond double laser beam super finishing equipment of the embodiment effectively overcomes this super finishing bottleneck, improves the multi-photon energy absorption rate through preheating by infrared pulse, and greatly increases the proportion of "cold processing";

[0150] The infrared pulse laser preheats the material in the front scanning, and the ultraviolet picosecond laser performs cold processing immediately after the scanning, which can maximize the proportion of "cold processing" and reduce thermal effect defects. By optimizing the scanning paths of the infrared pulse laser and the ultraviolet picosecond laser, the coupling optimization of the pulse laser and the ultraviolet picosecond laser is achieved, that is, the processed material is preheated to an optimized temperature, and the ultraviolet picosecond laser multi-photon is just right to be absorbed in the optimized temperature area. In this way, the multi-photon energy absorption rate will be greatly improved, and the purpose of super finishing can be achieved.

[0151] When the method of the embodiment is applied, a double laser beam super finishing system including two sets of three-dimensional galvanometers and two-axis numerical control rotary tables can be used, such as Figure 2As shown, the infrared pulse laser (50-300W) and ultrafast ultraviolet picosecond laser (50W) double laser beams are used to perform processing. Taking the texture processing of a complex mold cavity part as an example, the infrared pulse laser and the ultraviolet picosecond laser enter the three-dimensional galvanometer of the respective front focusing system. The Z-axis moving mirror and the XY-axis rotating mirror can control the movement of the focused laser spot on the surface of the three-dimensional cavity of the mold. The rotation of the two-axis (A, C) numerical control rotary table can expose the laser processing blind area of the mold cavity to the processing range of the three-dimensional galvanometer, and the galvanometer can process the blind area. If the processing is anisotropic surface, five-axis linkage is needed, the galvanometer only outputs a spot similar in size to the diameter of a mechanical processing tool, and the five-axis numerical control system controls the linkage of the five axes of the mechanical shaft XYZ and the AC rotary table AC, so that the laser spot can be precisely processed in any area of the anisotropic surface.

[0152] Further, other optional examples of the processing system can be found in the subsequent device embodiments.

[0153] The ideal ultraviolet picosecond laser "cold polishing" is to convert the micro-topography into the target shape by cold processing "peak cutting", so as to achieve the purpose of local finishing. The traditional mechanical polishing removes local peaks (which is a method of removing layer by layer, such as Figure 3 As shown, but the depth of focus of the focused ultraviolet picosecond laser is between 0.5-1.0mm, while the height of some peaks is below 0.1mm (in fact, there are very few ceramic parts with roughness greater than 0.2mm that need to be polished) so if the ultraviolet picosecond laser can perform 100% "cold polishing", it will be a one-time removal of local peaks.

[0154] But the single-photon energy of the ultraviolet laser does not completely match the chemical bond energy of the high brittle-hard material, and can only rely on limited multi-photons for lower degree "cold polishing", so only a few of the local peaks are cut off and form high brittle-hard material powder, and most of the peaks are still retained. Through the simultaneous "thermal processing", the laser energy is quickly melted, and finally "gasified", thus producing various defects of "thermal processing".

[0155] However, in this embodiment, the infrared pulse laser first preheats the surface of the high brittle-hard material part to an optimal temperature, and the absorption rate of the material to the multi-photons is greatly improved, so most of the local peaks are "cold processed" and cut off, and only a few are "thermally processed" and gasified. Therefore, the various defects produced by "thermal processing" are greatly reduced, and the precision polishing of high brittle-hard materials is achieved.

[0156] Further, in combination with the above-mentioned scheme of optimizing the scanning path of the dual laser beams, the "cold processing" polishing ratio can be further improved. Different materials require different scanning paths to ensure the optimization effect of the preheating temperature.

[0157] That is, as long as the 3D model of the micro-nano texture (i.e., the Poisson reconstruction result or the 3D structure of the polished surface) is obtained, the micro-nano texture (including micro-nano texture) can be super-finished by the method of the embodiment (infrared pulse laser preheating and ultraviolet picosecond laser cold processing).

[0158] The embodiment utilizes the infrared pulse and ultraviolet picosecond dual laser processing innovation technology to fully realize the maximization of laser "cold processing", so as to realize the precision polishing of the above-mentioned hard and brittle material, the passivation polishing of the ceramic tool, and the micro-nano texture processing of the mold and product.

[0159] The infrared pulse + ultraviolet picosecond laser beam precision machining technology, the dual laser beam composite scanning path technology, and the parameterized low deformation variable three-dimensional texture mapping method. The infrared pulse and ultraviolet picosecond dual laser super-finish equipment of the embodiment can not only perform precision polishing of hard and brittle materials, but also perform micro-nano texture processing of mold cavities and products. The principle is to utilize the infrared pulse laser to preheat the processed material, so that it can fully absorb the multiphoton generated by the ultraviolet laser. Then, the ultraviolet laser multiphoton is processed in the time domain of the ultra-narrow pulse width through cold processing, so as to achieve the purpose of precision polishing or micro-nano texture processing.

[0160] One of the cores of the dual laser source scheme is to optimize the preheating temperature of the processed material, improve the absorption rate of the ultraviolet laser multiphoton by the material, and thus improve the proportion of laser "cold processing".

[0161] On this basis, in combination with the above-mentioned dual laser beam composite scanning path, the scanning paths of the infrared pulse laser and the ultraviolet picosecond laser are optimized to achieve the purpose of coupling and optimizing the pulse laser and the ultraviolet picosecond laser, that is, the processed material is preheated to an optimized temperature, and the ultraviolet picosecond laser multiphoton is absorbed at the optimized temperature area.

[0162] Specifically, the hard and brittle material refers to any one or a combination of multiple of photovoltaic silicon material, semiconductor silicon material, sapphire material, magnetic material, optical glass, and ceramic material; the polished semiconductor SiC ceramic substrate is cold-processed and polished, the influence of thermal effect is greatly reduced, the semi-finish polishing of the SiC ceramic substrate can be performed, the polishing time can be greatly saved, and the overall polishing efficiency of the SiC ceramic substrate can be greatly improved.

[0163] In an optional embodiment of the present embodiment, the first laser source emits first laser having high power and wide pulse, which is beneficial for removing large and unnecessary material surface protrusions, and can adjust the temperature of the material surface, and by controlling the pulse width, power and irradiation time, the temperature of the material surface is increased to a set temperature which is beneficial for the second laser source to perform "cold processing", at which the absorption efficiency of the material surface of the workpiece to the second laser is more satisfactory.

[0164] Considering that the heating process requires high input energy, the first laser source needs to provide high power and wide pulse, and on this basis, the processing of the first laser on the workpiece surface cannot achieve the desired degree of fineness, so the processing of the first laser is defined as "preliminary processing".

[0165] In a preferred embodiment, the first laser source is an infrared laser source; the second laser source is an ultraviolet laser source; the power of the first laser source is greater than that of the second laser source; and the shortest pulse duration of the second laser source is femtosecond or picosecond.

[0166] The present embodiment has the following beneficial effects:

[0167] By using the first laser source and the second laser source to perform temperature control and processing control on the workpiece surface respectively, the target texture can be precisely processed in a more fine-grained manner, and a better quality target texture can be obtained. At the same time, by using the infrared laser source to achieve better temperature control effect and using the ultraviolet laser source to achieve more precise processing control, a better quality target texture can be obtained.

[0168] It should be understood that the size of the serial number of each step in the above embodiment does not mean the order of execution, and the execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation on the implementation process of the present embodiment.

[0169] The present embodiment also provides a multi-axis linkage laser superfinishing device, which can be used to perform the multi-axis linkage laser superfinishing method described above, as shown in Figure 2 , which comprises:

[0170] A turntable is used to fix the workpiece and can drive the workpiece to rotate around the x, y or z axis as the rotation axis in the preset Cartesian coordinate system;

[0171] A moving guide rail is mechanically connected with the turntable, and is used to drive the turntable and the workpiece fixed on the turntable to move along the x, y or z axis direction in the preset Cartesian coordinate system;

[0172] a first laser source configured to emit a first laser to the workpiece at a preset first frequency, first pulse width and first power to perform machining and / or preheating;

[0173] a first moving mechanism mechanically connected to the first laser source and configured to drive the first laser source to rotate around an x, y or z axis as a rotation axis in a preset Cartesian coordinate system and / or to translate along an x, y or z axis in the preset Cartesian coordinate system;

[0174] a second laser source configured to emit a second laser to the workpiece at a preset second frequency, second pulse width and second power to perform machining;

[0175] a second moving mechanism mechanically connected to the second laser source and configured to drive the second laser source to rotate around an x, y or z axis as a rotation axis in a preset Cartesian coordinate system and / or to translate along an x, y or z axis in the preset Cartesian coordinate system;

[0176] The first laser source and the second laser source can be independently moved or rotated by the first moving mechanism and the second moving mechanism.

[0177] Figure 2 An embodiment of a multi-axis linkage laser superfinishing device is shown, which comprises:

[0178] a first mechanical arm 2011 constituting the first moving mechanism;

[0179] a first laser generator (not shown in the figure), a first beam expander 2012 and a first focusing mirror 2013 constituting the first laser source;

[0180] a second mechanical arm 2021 constituting the second moving mechanism;

[0181] a second laser generator (not shown in the figure), a second beam expander 2022 and a second focusing mirror 2023 constituting the second laser source;

[0182] a sealed cavity 204 of the rotary table; and

[0183] a rotary worktable 203 of the moving guide rail.

[0184] In an embodiment, the device further comprises a mechanical arm, which is configured to:

[0185] move the workpiece from a feeding area to the rotary table and fix the workpiece; or

[0186] adjust a fixed pose of the workpiece fixed on the rotary table; or

[0187] The workpiece fixed on the turntable is moved to a material unloading area.

[0188] The following is a more comprehensive description of the innovative features of each embodiment of the present application, specifically:

[0189] (1) Laser processing equipment that combines infrared laser + ultraviolet picosecond dual laser beam polishing system will be successfully industrialized and implemented. It can not only achieve laser precision polishing of highly brittle hard materials, but also demonstrate its capabilities in the field of mold texture and micro-nano texture processing.

[0190] (2) Alternating dual laser beams are used for polishing. The infrared pulse laser plays the role of preheating and rough processing (only for conventional texture processing); the ultraviolet picosecond laser plays the role of maintaining temperature and playing the main "cold processing" role, which is the key to achieving ultra-precision processing.

[0191] (3) A new method of low-deformation, seamless three-dimensional geometric texture mapping based on global parameterization is used to achieve control optimization of texture mapping position and size based on three-dimensional surface model features to meet the processing requirements of mold cavity and product three-dimensional texture.

[0192] The advantages of the above embodiments are mainly reflected in:

[0193] (1) The laser processing equipment combining the infrared pulse laser + ultraviolet picosecond dual laser beam polishing system and based on the methods of the above-mentioned embodiments can improve the polishing accuracy of highly brittle and hard material parts to the level of Ra < 0.15μm, reaching the level of sub-mirror and near-mirror, achieving a breakthrough in the laser polishing accuracy of highly brittle and hard materials, and can effectively meet the precision polishing needs of highly brittle and hard materials such as 5G base station parts, ceramic coated tools, artificial diamond tools, drones, medical devices (including scalpels and implantable devices), aerospace, and so on.

[0194] (2) The laser processing equipment based on the above-mentioned embodiments can not only achieve sub-mirror or even mirror polishing effects, but also has an extremely high polishing efficiency.

[0195] (3) In addition to high precision and high efficiency, another advantage of the equipment using the methods of the above embodiments is that the innovative technical route enables the laser processing equipment to have a very competitive price in the market.

[0196] In combination with the above embodiments, the core solutions of this application include:

[0197] 1. A multi-axis laser ultra-precision machining method, comprising:

[0198] If the processing requirement is determined to be micro-nano texture processing, then:

[0199] acquire a geometric texture and a target surface; the target surface refers to a surface of a set region on a workpiece to be machined into a target texture; the target texture is a three-dimensional texture corresponding to the geometric texture and obtained based on the geometric texture; the target texture includes a polishing texture or a micro-nano machining texture;

[0200] extract a gradient field of texture information in the geometric texture, and perform gradient coding to obtain texture gradient information;

[0201] parameterize the geometric texture and the surface information in the target surface, and establish a surface mapping relationship from the geometric texture to the target surface;

[0202] solve a Poisson equation according to the surface mapping relationship and the texture gradient information to obtain a Poisson reconstruction result as a machining target structure, and determine a first laser track of a first laser and a second laser track of a second laser based on the machining target structure;

[0203] if the machining requirement is polishing of a hard and brittle material workpiece, then:

[0204] obtain a polishing surface as a machining target structure according to material parameters of the workpiece and a microstructure of the workpiece on the target surface;

[0205] determine a first laser track of a first laser and a second laser track of a second laser according to the machining target structure; the first laser is an infrared laser; the second laser is an ultraviolet laser; the power of the first laser is greater than that of the second laser; the shortest pulse duration of the second laser is femtosecond or picosecond order;

[0206] the first laser track and the second laser track are both multi-axis linkage tracks; the multi-axis linkage refers to that the workpiece, a first laser source emitting the first laser, and a second laser source emitting the second laser all have three translational degrees of freedom and at least two rotational degrees of freedom;

[0207] the first laser track and the second laser track are both tracks obtained by optimization under functional constraints; the functional constraints refer to that the first laser is used to heat a current machining layer to a preset temperature and perform preliminary machining; the second laser source emits a second laser to perform secondary cold machining on the current machining layer at the preset temperature; the cold machining refers to laser machining that utilizes high-energy photons to separate at least a part of molecules on the current machining layer from a material body without generating additional heat;

[0208] the multi-axis linkage laser superfinishing method further includes:

[0209] Performing red-ultraviolet dual-beam ultrafast laser layer-by-layer removal processing on the target curved surface by using the first laser moving along the first laser track and the second laser moving along the second laser track, to obtain a polished hard and brittle material workpiece or a micro-nano textured workpiece.

[0210] The hard and brittle material refers to any one or a combination of multiple of photovoltaic silicon material, semiconductor silicon material, sapphire material, magnetic material, optical glass, and ceramic material.

[0211] 2. The multi-axis linkage laser ultrafinishing method of 1, wherein the step of parameterizing the geometric texture and the curved surface information in the target curved surface, and establishing the curved surface mapping relationship of the geometric texture to the target curved surface comprises:

[0212] extracting the curved surface information in the geometric texture and parameterizing to obtain a basic curved surface parameter domain;

[0213] globally parameterizing the target curved surface to obtain a target curved surface parameter domain;

[0214] determining the corresponding relationship of the curved surface boundary and vertex as a boundary constraint according to the basic curved surface parameter domain and the target curved surface parameter domain;

[0215] under the boundary constraint, determining a local transformation of any region in the basic curved surface parameter domain to a corresponding region in the target curved surface parameter domain; the local transformation comprises a rotation transformation and / or a scale transformation; a set of local transformations of at least a part of the curved surface in the basic curved surface parameter domain to at least a part of the curved surface in the target curved surface parameter domain constitutes the curved surface mapping relationship;

[0216] the step of solving a Poisson equation according to the curved surface mapping relationship and the texture gradient information to obtain a Poisson reconstruction result comprises:

[0217] under the constraint of the curved surface mapping relationship, integrating the texture gradient information by using the Poisson equation to obtain the gradient information under the target curved surface as the Poisson reconstruction result.

[0218] 3. The multi-axis linkage laser ultrafinishing method of 2, wherein the target curved surface is composed of a constraint region and a non-constraint region; the constraint region refers to a region in which the rotation transformation and / or the scale transformation of the set local transformation meet a preset distortion parameter;

[0219] the step of solving a Poisson equation according to the curved surface mapping relationship and the texture gradient information to obtain a Poisson reconstruction result comprises:

[0220] Integrate the texture gradient information by using a Poisson equation under the constraints of the curved surface mapping relationship and the constraint region corresponding to the distortion parameter, to obtain gradient information under the target curved surface as a Poisson reconstruction result.

[0221] 4. A laser micro-nano texture processing device based on texture mapping, comprising:

[0222] A texture module configured to, if the processing requirement is micro-nano texture processing, then:

[0223] obtain a geometric texture and a target curved surface; the target curved surface refers to a surface of a set region on a workpiece to be processed into a target texture; the target texture is a three-dimensional texture corresponding to the geometric texture and obtained based on the geometric texture; the target texture includes a polishing texture or a micro-nano processed texture;

[0224] extract a gradient field of texture information in the geometric texture and perform gradient coding to obtain texture gradient information;

[0225] parameterize curved surface information in the geometric texture and the target curved surface, and establish a curved surface mapping relationship from the geometric texture to the target curved surface;

[0226] solve a Poisson equation according to the curved surface mapping relationship and the texture gradient information to obtain a Poisson reconstruction result as a processing target structure, and determine a first laser track of a first laser and a second laser track of a second laser based on the processing target structure;

[0227] A polishing module configured to, if the processing requirement is polishing of a hard and brittle material workpiece, then:

[0228] obtain a polished surface as a processing target structure according to material parameters of the workpiece and a microstructure of the workpiece on the target curved surface;

[0229] determine a first laser track of a first laser and a second laser track of a second laser according to the processing target structure; the first laser is an infrared laser; the second laser is an ultraviolet laser; the power of the first laser is greater than that of the second laser; the shortest pulse duration of the second laser is femtosecond or picosecond order;

[0230] the first laser track and the second laser track are both multi-axis linkage tracks; the multi-axis linkage refers to that the workpiece, a first laser source emitting the first laser, and a second laser source emitting the second laser all have three translational degrees of freedom and at least two rotational degrees of freedom;

[0231] The first laser track and the second laser track are both tracks optimized under functional constraints; the functional constraints refer to that the first laser is used to heat the current processing layer to a preset temperature and perform preliminary processing; the second laser emitted by the second laser source is used to perform secondary cold processing on the current processing layer at the preset temperature; the cold processing refers to laser processing that utilizes high-energy photons to separate at least part of the molecules on the current processing layer from the material body without generating additional heat;

[0232] a processing module configured to perform red-ultraviolet dual-beam ultrafast laser layer-by-layer removal processing on the target surface using the first laser moving along the first laser track and the second laser moving along the second laser track, to obtain a polished hard and brittle material workpiece, or a micro-nano textured workpiece;

[0233] The hard and brittle material refers to any one or a combination of more than one of photovoltaic silicon material, semiconductor silicon material, sapphire material, magnetic material, optical glass, and ceramic material.

[0234] 5. A multi-axis linkage laser ultra-precision machining device capable of performing the multi-axis linkage laser ultra-precision machining method of any one of 1 to 3, comprising:

[0235] A rotary table configured to fix the workpiece and capable of rotating the workpiece around the x, y, or z axis as the rotation axis in a preset Cartesian coordinate system;

[0236] A moving guide rail mechanically connected with the rotary table and configured to move the rotary table and the workpiece fixed on the rotary table along the x, y, or z axis direction in a preset Cartesian coordinate system;

[0237] A first laser source configured to emit first laser to the workpiece at a preset first frequency, first pulse width, and first power to perform processing and / or preheating;

[0238] A first moving mechanism mechanically connected with the first laser source and configured to rotate the first laser source around the x, y, or z axis as the rotation axis in a preset Cartesian coordinate system, and / or move the first laser source along the x, y, or z axis direction in a preset Cartesian coordinate system;

[0239] A second laser source configured to emit second laser to the workpiece at a preset second frequency, second pulse width, and second power to perform processing;

[0240] A second moving mechanism mechanically connected with the second laser source and configured to rotate the second laser source around the x, y, or z axis as the rotation axis in a preset Cartesian coordinate system, and / or move the second laser source along the x, y, or z axis direction in a preset Cartesian coordinate system;

[0241] The first laser source and the second laser source can be moved or rotated independently of the turntable under the driving of the first moving mechanism and the second moving mechanism.

[0242] In the above embodiments, the description of each embodiment has its own focus, and the parts not described or recorded in a certain embodiment can be referred to the relevant description of other embodiments.

[0243] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solutions. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0244] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, i.e. they can be located in one place or distributed on multiple network units. Part or all of the units can be selected to achieve the purpose of the embodiments according to actual needs.

[0245] The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A multi-axis laser ultra-precision machining method, characterized in that: include: Micro-nano three-dimensional texture precision machining and ultra-precision polishing methods for hard and brittle materials. If the processing requirements are determined to be micro-nano texture machining, then: Acquire a geometric texture and a target surface; the target surface is a surface of a set area on a workpiece to be processed into a target texture; the target texture is a three-dimensional texture obtained based on the geometric texture and corresponding to the geometric texture; the target texture includes a micro-nano three-dimensional processing texture; Extracting texture information from the geometric texture and performing gradient coding to obtain texture gradient information; Parameterizing the surface information of the geometric texture and the target surface, and establishing a surface mapping relationship from the geometric texture to the target surface; Solving the Poisson equation according to the surface mapping relationship and the texture gradient information to obtain a Poisson reconstruction result as a processing target structure, and determining a first laser trajectory of the first laser and a second laser trajectory of the second laser based on the processing target structure; If the processing requirement is to polish hard and brittle material workpieces, then: According to the material parameters of the workpiece and the microstructure of the workpiece on the target surface, a polished surface is obtained as the processing target structure; Determining a first laser trajectory of a first laser and a second laser trajectory of a second laser according to the processing target structure; the first laser is an infrared laser; the second laser is an ultraviolet laser; the power of the first laser is greater than that of the second laser; and the shortest pulse duration of the second laser is in the order of femtoseconds or picoseconds; The step of parameterizing the surface information of the geometric texture and the target surface and establishing a surface mapping relationship from the geometric texture to the target surface includes: Extracting and parameterizing the surface information in the geometric texture to obtain a basic surface parameter domain; Globally parameterizing the target surface to obtain a target surface parameter domain; Determining a correspondence between a surface boundary and vertices as a boundary constraint according to the base surface parameter domain and the target surface parameter domain; Under the boundary constraint, a local transformation of any region in the base surface parameter domain to a corresponding region in the target surface parameter domain is determined; the local transformation includes a rotation transformation and / or a scale transformation; a set of local transformations from at least a portion of the surface in the base surface parameter domain to at least a portion of the surface in the target surface parameter domain constitutes the surface mapping relationship; wherein the partitions of the target surface and the surface corresponding to the geometric texture correspond to each other, and the number of partitions of the target surface and the surface corresponding to the geometric texture is the same; The step of solving the Poisson equation according to the surface mapping relationship and the texture gradient information to obtain a Poisson reconstruction result includes: Under the constraint of the surface mapping relationship, the texture gradient information is integrated using the Poisson equation to obtain the gradient information under the target surface as a Poisson reconstruction result.

2. The multi-axis laser ultra-precision machining method according to claim 1, wherein: The target surface is composed of a constrained area and an unconstrained area; the constrained area refers to an area where the rotation transformation and / or scale transformation of the set local transformation meets the preset distortion parameters; The step of solving the Poisson equation according to the surface mapping relationship and the texture gradient information to obtain a Poisson reconstruction result includes: Under the constraints of the surface mapping relationship and the distortion parameter corresponding to the constraint area, the texture gradient information is integrated using the Poisson equation to obtain the gradient information under the target surface as a Poisson reconstruction result.

3. The multi-axis laser ultra-precision machining method according to claim 1, wherein: Three-dimensional texture is a microscopic micro-nano structure, mapped on the surface with an distortion rate of <5%, and the geometric texture after mapping is extracted by shelling, making it the planning object of laser beam processing trajectory; low deformation control, boundary texture processing, texture extension, algorithm efficiency, algorithm robustness, rendering and interactive interface; After the texture is mapped on the surface, a multi-layer laser processing trajectory can be generated to form a three-dimensional texture through subtractive manufacturing.

4. The multi-axis laser ultra-precision machining method according to claim 1, wherein: The ultra-precision polishing method for hard and brittle materials is a dual-laser beam precision polishing method for highly brittle and hard materials. Infrared pulse laser preheats the surface of the part to an optimized temperature below the melting point to improve the ultraviolet laser multi-photon absorption rate of the material.

5. The multi-axis laser ultra-precision machining method according to claim 3, wherein: The hard and brittle material refers to any one or a combination of any two or more of photovoltaic silicon materials, semiconductor silicon materials, sapphire materials, magnetic materials, optical glass and ceramic materials.

6. The multi-axis laser ultra-precision machining method according to claim 1, wherein: The method comprises: dual laser beam processing, wherein the first laser is an infrared laser; the second laser is an ultraviolet laser; the power of the first laser is greater than that of the second laser; and the shortest pulse duration of the second laser is in the order of femtoseconds or picoseconds; The first laser trajectory and the second laser trajectory are both multi-axis linkage trajectories; the multi-axis linkage means that the workpiece, the first laser source emitting the first laser, and the second laser source emitting the second laser all have three translational degrees of freedom and at least two rotational degrees of freedom.

7. The multi-axis laser ultra-precision machining method according to claim 6, wherein: include: The first laser trajectory and the second laser trajectory are both optimized trajectories under functional constraints; the functional constraints are: the first laser is used to heat the current processing layer to a preset temperature and perform preliminary processing; the second laser is used to perform secondary cold processing on the current processing layer at the preset temperature; cold processing refers to laser processing that uses high-energy photons to separate at least a portion of molecules in the current processing layer from the main material without generating additional heat; A first laser moving along the first laser trajectory and a second laser moving along the second laser trajectory are used to perform red-ultraviolet dual-beam ultrafast laser layer-by-layer removal processing on the target surface to obtain a polished hard and brittle material workpiece, or a workpiece after micro-nano texture processing.

8. The multi-axis linkage laser ultra-precision machining method according to claim 1 is applied to a multi-axis linkage laser ultra-precision machining device, characterized in that: The device comprises: A turntable, used to fix the workpiece and capable of driving the workpiece to rotate around the x, y or z axis in a preset Cartesian coordinate system; A movable guide rail mechanically connected to the turntable, for driving the turntable and the workpiece fixed thereon to move in translation along the x-axis, y-axis or z-axis in a preset Cartesian coordinate system; a first laser source, configured to emit a first laser at a preset first frequency, a first pulse width, and a first power to the workpiece to perform processing and / or preheating; a first moving mechanism mechanically connected to the first laser source, configured to drive the first laser source to rotate about an x-axis, a y-axis, or a z-axis in a preset Cartesian coordinate system, and / or to move the first laser source in a translational direction along an x-axis, a y-axis, or a z-axis in a preset Cartesian coordinate system; A second laser source, configured to emit a second laser at a preset second frequency, second pulse width, and second power to the workpiece to perform processing; a second moving mechanism mechanically connected to the second laser source, configured to drive the second laser source to rotate about the x, y, or z axis in a preset Cartesian coordinate system, and / or to move the second laser source in a translational direction along the x, y, or z axis in a preset Cartesian coordinate system; Driven by the first moving mechanism and the second moving mechanism, the first laser source and the second laser source can move or rotate independently of the turntable.

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