A laser-grinding composite machining method for micro-slots of difficult-to-machine materials

Abstract

The application provides a laser-grinding combined machining method for micro-slots of difficult-to-machine materials, and relates to the technical field of micro-slot machining of difficult-to-machine materials.The method ensures the unity of positioning datum by designing a multi-process integrated special fixture, adopts laser layer-by-layer scanning to machine the bottom groove, calculates the machining allowance through nondestructive testing, and finally adopts grinding layer-by-layer finishing.The laser rough machining and grinding finishing are linked, the laser flux and grinding parameters are dynamically adjusted in depth, the efficiency and precision are taken into account, the problems of laser heat influence, low grinding efficiency and tool damage are solved, and the method is suitable for machining of precise structures such as closed micro-slots.The application proposes the machining idea of laser machining of the bottom groove and grinding finishing to obtain high-quality grooving, aiming at the problems existing in the machining of micro-slots of difficult-to-machine materials by a single method, greatly improves the machining efficiency and machining quality, and provides a theoretical basis and technical support for the precision machining of micro-slots of difficult-to-machine materials.

Description

Technical Field

[0001] This invention relates to the field of special processing of difficult-to-machine materials, and in particular to a laser-grinding composite processing method for microgrooves in difficult-to-machine materials. Background Technology

[0002] As next-generation aero-engines develop towards higher thrust-to-weight ratios and greater maneuverability, the materials used in their components have achieved breakthroughs in high-temperature resistance, structural strength, and lightweight properties. However, these more advanced materials also bring greater processing challenges. For example, turbine inlet temperatures can reach 2200K-2450K, and the temperature limits of traditional alloy materials differ significantly from their service temperatures. Therefore, new high-temperature resistant materials such as high-temperature alloys, ceramic matrix composites, and metal matrix composites have become the focus of attention. Taking ceramic matrix composites as an example, they possess excellent properties such as low density, resistance to high-temperature oxidation, and corrosion resistance, and have broad application prospects in hot-end components such as turbine outer rings and guide vanes.

[0003] However, ceramic matrix composites are composed of heterogeneous multiphase materials such as fibers, matrix, and interfaces, exhibiting characteristics such as high hardness, brittleness, multiphase heterogeneity, anisotropy, and poor electrical conductivity, making them typical difficult-to-machine materials. Meanwhile, hot-end components require the fabrication of various functional microstructures, such as sealing grooves and film pores, due to assembly, heat dissipation, and sealing requirements. Taking sealing grooves as an example, as closed microgrooves, they possess structural characteristics of being long, narrow, and deep (length ≥ 50 mm, width ≤ 500 μm, depth ≥ 3 mm). During the machining of sealing grooves, their contour accuracy and surface roughness significantly impact sealing performance, and machining efficiency determines the manufacturing cycle length of hot-end components; a balance must be struck between machining quality and efficiency.

[0004] Laser processing offers advantages such as wide material adaptability, no tool wear, and high processing efficiency. However, it also presents challenges, including the inability to fix the focal length, the presence of a heat-affected zone, and difficulty in controlling contour accuracy. Furthermore, it is prone to inherent defects like uneven bottoms when machining flat-bottomed grooves. Grinding, while capable of machining hard and brittle materials and excelling in complex surface processing with high precision, suffers from low efficiency. When machining deep, narrow flat-bottomed grooves, such as sealing grooves, tool wear and breakage are extremely common, severely impacting efficiency and making it unsuitable for large-scale production. Moreover, when laser and grinding are used separately, inconsistent positioning benchmarks between processes can lead to accumulated machining errors, further affecting accuracy.

[0005] Therefore, a single processing method cannot simultaneously achieve both processing efficiency and quality for microgrooves in difficult-to-machine materials. These issues significantly limit the application and development of high-performance materials. Therefore, there is an urgent need to propose a novel processing method to achieve high-quality and efficient processing of microgrooves in difficult-to-machine materials. Summary of the Invention

[0006] This invention addresses the aforementioned problems by proposing a laser-grinding composite machining method for microgrooves in difficult-to-machine materials. To overcome the limitations of conventional single-method approaches in creating microgrooves in such materials, this invention proposes a machining approach that first laser-machines the grooves, followed by grinding and finishing to obtain high-quality grooves. This significantly improves machining efficiency and quality, providing a theoretical foundation and technical support for the machining and application of difficult-to-machine materials. The method includes the design of multi-process integrated special fixtures, the setting of composite processes, laser processing strategies, and grinding techniques. This invention is applicable to the precision machining of closed (e.g., sealed grooves), semi-closed, and open microgrooves in difficult-to-machine materials such as high-temperature alloys, ceramic matrix composites, and metal matrix composites. It is particularly suitable for the high-quality and efficient machining of deep and narrow microgrooves (length ≥ 50 mm, width ≤ 500 μm, depth ≥ 3 mm) in hot-end components of aero-engines.

[0007] The technical means employed in this invention patent are as follows:

[0008] A laser-grinding composite machining method for microgrooves in difficult-to-machine materials includes the following steps:

[0009] Step S1: Analyze the microgroove structure characteristics and design and manufacture a multi-process integrated special fixture. This fixture ensures that the positioning reference of the workpiece is consistent in subsequent laser and grinding processes.

[0010] Step S2: Design the composite processing flow of laser processing of the bottom groove and grinding and finishing of the groove;

[0011] Step S3: Use a laser to perform layer-by-layer scanning processing on the workpiece. The processing adopts a layer-by-layer scanning strategy that dynamically adjusts the laser flux according to the current processing depth to form a bottom groove on the workpiece that is close to the theoretical contour and leaves a margin.

[0012] Step S4: Detect the bottom groove and calculate its machining allowance relative to the target micro-groove; based on the calculated allowance distribution, use grinding technology to trim the bottom groove. The trimming adopts a layered feed strategy that is dynamically adjusted according to the current grinding depth, and finally produces a micro-groove that meets the requirements of contour accuracy and surface quality.

[0013] Furthermore, in step S1:

[0014] The microgroove structure includes, but is not limited to, closed microgrooves, semi-closed microgrooves, and open microgrooves. The design of the multi-process integrated special fixture is based on the machining surface and angle constraints of the microgroove structure; it analyzes the force characteristics in laser non-contact machining and grinding contact machining processes, adopts a modular design, includes detachable / replaceable positioning elements to meet the clamping requirements of different process characteristics, and uses materials and structures with vibration reduction properties. At the same time, it sets a preset clamping force to ensure the accurate inheritance of positioning references between processes and the stability of process connection.

[0015] Furthermore, the layered scanning process described in step S3 specifically includes: the laser focus is initially located on the upper surface of the workpiece; after completing one layer of scanning processing, the focus moves downwards along the depth direction by a preset distance to start the next layer of scanning processing, and the processing is repeated until the target bottom groove depth is reached.

[0016] Furthermore, in step S3, the flux distribution after the laser scanning paths are superimposed is calculated; based on the quantitative relationship between material removal characteristics and laser flux, a layered scanning path based on laser flux regulation is designed; and the bottom groove is formed by processing layer by layer according to the designed path.

[0017] Furthermore, the types of lasers used include, but are not limited to, continuous lasers and pulsed lasers. Pulsed lasers include, but are not limited to, millisecond lasers, nanosecond lasers, picosecond lasers, and femtosecond lasers. The processing methods used include, but are not limited to, mechanical scanning processing, galvanometer scanning processing, and rotary cutting processing. The scanning paths include, but are not limited to, reciprocating straight paths along the long side, sinusoidal paths along the long side, and reciprocating straight paths along the short side.

[0018] Furthermore, the layered scanning strategy specifically involves dynamically adjusting the laser flux based on the current processing depth during the layered scanning process; using a higher laser flux to improve efficiency when the processing depth is less than 2 / 3 of the total depth, and using a lower laser flux to improve contour accuracy when the processing depth is greater than 2 / 3 of the total depth.

[0019] Furthermore, step S4 involves inspecting the bottom groove and calculating its machining allowance relative to the target micro-groove, specifically including:

[0020] With the workpiece and fixture in a clamped state, a three-dimensional contour scan of the bottom groove is performed using non-destructive testing technology, and the contour scan results are used for process optimization in step S3. Based on the scan data, the contour model of the bottom groove is reconstructed, and the model is compared with the theoretical model of the target microgroove to calculate the machining allowance for each region. The morphology model and machining allowance data of the bottom groove are associated with the laser processing parameters of step S3. A prediction scheme with a hybrid architecture of neural network and physical simulation is used to establish a mapping relationship database between laser processing parameters, bottom groove morphology and machining allowance. Once the accuracy of the database meets the requirements, the machining allowance can be directly obtained from the laser processing parameters.

[0021] Furthermore, in step S4, grinding technology is used to finish the bottom groove, specifically including:

[0022] Based on the calculated machining allowance, the feed path of the grinding tool is designed; layer-by-layer grinding is adopted to remove the allowance layer by layer according to the designed path; when the grinding depth reaches the set detection position, the wear state of the grinding tool is detected; based on the detected tool wear, position or size compensation is performed in the subsequent grinding path; grinding continues until the final required contour accuracy and surface quality are achieved.

[0023] The grinding dressing method further described above is characterized in that the grinding process used includes, but is not limited to, ordinary grinding process, ultrasonic assisted grinding process, etc., the grinding trajectory includes, but is not limited to, straight reciprocating type along the long side, sinusoidal type along the long side, straight reciprocating type along the short side, etc., and the grinding wheel used includes, but is not limited to, electroplated grinding wheel, sintered grinding wheel, brazed grinding wheel, etc.

[0024] Furthermore, in the layered feed strategy, when the grinding depth is less than 2 / 3 of the total depth, a larger depth of cut and feed rate are used to improve efficiency, and when the grinding depth is greater than 2 / 3 of the total depth, a smaller depth of cut and feed rate are used to reduce the risk of tool wear, thereby ensuring machining stability and final accuracy.

[0025] Compared with existing technologies, this invention has the following advantages: 1. Addressing the problem that conventional single-method processing is insufficient for creating closed microgrooves in difficult-to-machine materials, this invention proposes a processing approach that involves first laser pre-fabrication of microgrooves, followed by grinding and finishing to obtain high-quality closed microgrooves. This solves the problem of balancing processing efficiency and quality, providing a theoretical basis and technical support for the processing and application of microgrooves in difficult-to-machine materials. Specifically, laser roughing rapidly removes a large amount of excess material, significantly improving efficiency compared to pure grinding, while grinding finishing ensures surface quality and precision, ultimately achieving a surface roughness of (…). R a) Compared with single laser processing, the combination of the two achieves synergy of efficient removal and high-quality forming, providing a feasible solution for microgroove processing of difficult-to-machine materials.

[0026] 2. The unified positioning datum of the modular fixture of this invention avoids positioning deviations between laser and grinding processes, ensuring controllable errors in roughing and finishing, and solving the problem of error accumulation in traditional process connections. This invention proposes a layered scanning strategy in laser processing that dynamically adjusts the laser flux based on the processing depth. When the processing depth is small, a relatively high laser flux is used to improve efficiency; when the processing depth is large, a relatively low laser flux is used to improve contour accuracy. Layered processing ensures uniform laser energy distribution, avoiding thermal damage caused by excessive energy in a single processing pass; dynamic flux adjustment prioritizes efficiency at small depths and contour accuracy at large depths, balancing the high efficiency of laser processing with the quality of the groove.

[0027] 3. This invention proposes a layered feed strategy that dynamically adjusts grinding parameters considering tool wear and grinding depth. When the grinding depth reaches a set detection position, the wear state of the grinding tool is detected. Based on the detected tool wear, positional or dimensional compensation is performed in the subsequent grinding path. When the grinding depth is small, a relatively large depth of cut and feed rate are used to improve efficiency; when the grinding depth is large, a relatively small depth of cut and feed rate are used to reduce the risk of tool wear, ensure machining stability, and maintain final accuracy. Layered grinding reduces the tool load in deep groove machining by gradually decreasing the depth of cut and feed rate; real-time wear detection and compensation ensure final dimensional accuracy, solving the problem of accuracy loss due to tool wear in traditional grinding. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic flowchart of a laser-grinding composite machining method for microgrooves of difficult-to-machine materials provided by the present invention.

[0030] Figure 2 This is a schematic diagram of the microgroove structure of the present invention.

[0031] Figure 3 This is a schematic diagram of the sealing groove fixture of the present invention.

[0032] Figure 4 This is a schematic diagram of some laser processing methods of the present invention.

[0033] Figure 5 This is a schematic diagram of part of the processing trajectory of the present invention.

[0034] Figure 6 This is a schematic diagram of layered processing in the laser processing of this invention.

[0035] Figure 7 This is a schematic diagram illustrating the laser processing process and results of the bottom groove according to the present invention.

[0036] Figure 8 This is a schematic diagram of the three-dimensional scanning and trimming allowance calculation of the bottom groove of the present invention.

[0037] Figure 9 This is a schematic diagram illustrating the grinding and finishing process and results of the present invention.

[0038] In the diagram: 1. Workpiece; 2. Main fixing module; 3. Clamping and positioning surface; 4. Positioning pin; 5. Positioning surface; 6. Fixture body; 7. Secondary fixing module. Detailed Implementation

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0042] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0043] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0044] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0045] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0046] like Figure 1 As shown, this embodiment of the invention provides a laser-grinding composite machining method for microgrooves in difficult-to-machine materials. In this embodiment, femtosecond laser-ultrasonic grinding of a sealed groove in a ceramic matrix composite material is used as an example. Of course, this invention can also be extended to other laser and grinding methods to process closed microgrooves, semi-closed microgrooves, and open microgrooves. The method includes the following steps:

[0047] Step S1: Analyze the microgroove structure characteristics and design and manufacture a multi-process integrated special fixture. This fixture ensures that the positioning reference of the workpiece is consistent in subsequent laser and grinding processes.

[0048] Specifically, the machining surfaces and angles of the sealing groove are analyzed, such as... Figure 2As shown, its dimensions span a very large area, are closed at the ends, and have a depth-to-diameter ratio ≥6 (500μm wide, 3000μm deep). Considering the force characteristics during laser non-contact machining and grinding contact machining, alloy steel was selected to balance strength and vibration damping performance, and a design was developed as follows... Figure 3 The fixture shown employs a main and auxiliary fixing module combination structure, which can adapt to the different force requirements of laser processing and grinding processing respectively. The overall symmetrical layout enables the processing of sealing grooves on both sides in one clamping, improving processing efficiency. The positioning system adopts a combination of positioning surfaces and positioning pins, with positioning pins divided into fixed and semi-movable types to expand the workpiece applicability range. An additional positioning structure is added to the auxiliary fixing module to form an over-constraint structure, effectively ensuring positioning accuracy and repeatability, and ensuring the consistency of positioning references and the stability of processing connection between processes. Based on the fixture body, the main fixing module, auxiliary fixing module and positioning system are integrated to adapt to the force differences of laser (non-contact) and grinding (contact) processing methods, enabling multi-process processing to be completed in one clamping and avoiding positioning reference deviation. Specifically, the fixture body 6 serves as the basic support structure of the entire fixture, and core components such as the main fixing module 2 and auxiliary fixing module 7 are installed on it. The main fixing module 2 is connected to the fixture body 6, located on one side of the workpiece, and fixes the workpiece in conjunction with the positioning pin 4 and positioning surface 5. The auxiliary fixing module 7 is connected to the fixture body 6 and located on the other side of the workpiece. The contact area between the main fixing module 2 and the workpiece 1 has a positioning surface that conforms to the workpiece surface. The fixture body has a positioning surface 5 that conforms to the workpiece's reference surface. The workpiece has pre-set positioning holes, and precise positioning of the workpiece is achieved by inserting positioning pins 4 into these holes. The main fixing module has semi-movable positioning pins, allowing for small-range adjustment of position or tightness to accommodate workpieces of different sizes or positioning hole tolerances. Through this fixture design, the workpiece's position remains unchanged during laser groove machining and grinding, ensuring accurate machining allowance calculations and seamless process connections.

[0049] Step S2: Design the composite processing flow of laser processing of the bottom groove and grinding and finishing of the groove;

[0050] Step S3: Use a laser to perform layer-by-layer scanning processing on the workpiece. The processing adopts a layer-by-layer scanning strategy that dynamically adjusts the laser flux according to the current processing depth to form a bottom groove on the workpiece that is close to the theoretical contour and leaves a margin.

[0051] Specifically, the flux distribution after the laser scanning paths are superimposed is first calculated. Based on the quantitative relationship between the material removal characteristics of ceramic matrix composites and laser flux, a layered scanning path based on laser flux regulation is designed.

[0052] The bottom groove is formed layer by layer according to the designed path. In this implementation example, a femtosecond laser is used, with an output Gaussian laser beam of 1035 nm wavelength, a pulse width of 200 fs, a beam waist radius of 27.5 μm, and a maximum power of 60 W. The processing methods used include, but are not limited to, those described above. Figure 4 The mechanical scanning processing, galvanometer scanning processing, and rotary cutting processing shown are described. In this embodiment, femtosecond laser rotary cutting processing is selected. Figure 5 As shown, the scanning path includes, but is not limited to, a straight reciprocating pattern along the long side, a sinusoidal pattern along the long side, and a straight reciprocating pattern along the short side. This implementation example uses the straight reciprocating pattern along the long side, with a reciprocating interval of 60 μm and a cutting speed of 80 mm / s. The laser flux is calculated as follows:

[0053] First, determine the location of the center of the light spot.

[0054] (1)

[0055] (2)

[0056] in, x 0、 y 0 is the initial coordinate of the laser rotation center. v x , v y The speed at which the center of rotation moves. r The radius of the beam rotation. θ The angle between the center of the beam spot and the center of rotation. Spatial flux distribution of the Gaussian beam at this point. E i for:

[0057] (3)

[0058] in, P For laser power, f The laser frequency, ω The radius of the laser Rayleigh ray. After considering the influence of the ablation threshold, the amount of material removed. M The relationship with laser flux is as follows:

[0059] (4)

[0060] in M i The amount of material removed per laser pulse. δ This represents the material removal coefficient.

[0061] A layered feed strategy is employed to trim the bottom groove. Specifically, the layered processing involves initially positioning the laser focus on the upper surface of the workpiece. After completing one layer of scanning, the focus moves downwards a specified distance along the depth direction to begin the next layer of scanning. Figure 6 As shown, repeat this process until the target bottom trench depth is reached.

[0062] During the layered scanning process, the laser flux is dynamically adjusted according to the current processing depth. When the processing depth is less than 2 / 3, a laser flux of 8-10 times that of the ablation threshold is used to improve efficiency. When the processing depth is greater than 2 / 3, a laser flux of 4-5 times that of the ablation threshold is used to improve contour accuracy.

[0063] A schematic diagram of the laser-processed bottom groove is shown below. Figure 7 As shown.

[0064] Step S4: The bottom groove is inspected and its machining allowance relative to the target micro-groove is calculated. Based on the calculated allowance distribution, the bottom groove is trimmed using grinding technology. The trimming adopts a layered feed strategy that is dynamically adjusted according to the current grinding depth, and finally a micro-groove that meets the requirements of contour accuracy and surface quality is produced.

[0065] Specifically, firstly, the bottom groove after laser processing is inspected and its machining allowance relative to the target sealing groove is calculated. With the workpiece and fixture in a clamped state, a three-dimensional contour scan of the bottom groove is performed using a confocal microscope, and the scan results are used for process optimization in step S3. Based on the scan data, a morphological model of the bottom groove is reconstructed; the model is compared with the theoretical model of the target sealing groove, and the machining allowance for each region is calculated, such as... Figure 8 As shown, the morphology model of the bottom groove, the machining allowance data, and the femtosecond laser processing parameters are designed based on the core entity and relationship of the ER model. A prediction scheme with a hybrid architecture of neural network and physical simulation is adopted to establish a mapping relationship database of femtosecond laser processing parameters, bottom groove morphology and machining allowance. After the database accuracy meets the requirements, the machining allowance can be directly obtained from the laser processing parameters.

[0066] Subsequently, based on the calculated machining allowance, the feed path of the grinding tool is designed. In this embodiment, ultrasonic-assisted grinding technology is selected. Appropriate ultrasonic parameters are set: spindle speed 6000-9000 r / min, feed rate 100-150 mm / min. Layered grinding is employed, with an axial depth of cut of 0.004-0.008 mm. The allowance is removed layer by layer according to the designed path. When the grinding depth reaches 1 / 2 and 5 / 6 of the target depth of the sealing groove, the wear state of the grinding tool is detected to obtain the wear depth. L d Based on the detected tool wear amount L d Position or dimensional compensation is performed in subsequent grinding paths; grinding continues until the final required contour accuracy and surface quality are achieved.

[0067] During the layered grinding dressing process, the grinding parameters are dynamically adjusted according to the current grinding depth. Specifically, when the grinding depth is less than 2 / 3, a relatively large depth of cut of 0.008 mm and a feed rate of 150 mm / min are used to improve efficiency. When the grinding depth is greater than 2 / 3, a relatively small depth of cut of 0.004 mm and a feed rate of 100 mm / min are used to reduce the risk of tool wear, ensure machining stability and final accuracy.

[0068] Schematic diagram of grinding and finishing sealing groove as shown Figure 9 As shown.

[0069] Compared with the single process of ultrasonic grinding, the femtosecond laser-ultrasonic assisted grinding composite machining method for microgrooves provided by this invention reduces the number of tools required from 6 to 3, saving 50% on tool costs; the machining time for a single sealing groove is reduced from 8 hours to 4 hours, increasing efficiency by 100%; and the machining quality is improved from... R a 5.3μm increased to R The microgroove diameter is 2.67 μm. This invention significantly improves the processing efficiency of microgrooves while optimizing the processing quality, providing a theoretical basis and technical support for the precision machining of microgrooves in difficult-to-machine materials.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser-grinding combined machining method for micro-slots of difficult-to-machine materials, characterized in that, The method comprises the following steps: Step S1, analyze the characteristics of the micro-groove structure, and design and manufacture a multi-process integrated special fixture to ensure that the positioning reference of the workpiece is uniform in subsequent laser and grinding processes; Step S2, design a composite machining process flow for laser processing of the bottom groove and grinding of the finished groove; Step S3, use laser to perform layered scanning processing on the workpiece, and the processing adopts a layered scanning strategy for dynamically adjusting laser flux according to the current processing depth to form a bottom groove on the workpiece that is close to the theoretical profile and has a margin; Step S4, detect the bottom groove and calculate the processing margin of the target micro-groove; based on the calculated margin distribution, use grinding technology to trim the bottom groove, and the trimming adopts a layered feed strategy for dynamic adjustment according to the current grinding depth, and finally processes a micro-groove that meets the profile precision and surface quality requirements; In step S3: Calculate the flux distribution after superimposing the laser scanning path; design a layered scanning path based on laser flux regulation according to the quantitative relationship between material removal characteristics and laser flux; form the bottom groove by layering processing according to the designed path; during the layered scanning processing, dynamically adjust the laser flux according to the current processing depth; when the processing depth is less than 2 / 3 of the total depth, a preset higher laser flux is used, and when the processing depth is greater than 2 / 3 of the total depth, a preset lower laser flux is used; The trimming of the bottom groove using grinding technology in step S4 specifically includes: Design the feed path of the grinding tool according to the calculated processing margin; remove the margin layer by layer in the manner of layered grinding according to the designed path; when the grinding depth reaches the set detection position, detect the wear state of the grinding tool; according to the detected tool wear, position or size compensation is made in the subsequent grinding path; continue grinding until the required profile precision and surface quality are achieved; In the layered feed strategy, when the grinding depth is less than 2 / 3 of the total depth, a preset larger cutting depth and feed speed are used, and when the grinding depth is greater than 2 / 3 of the total depth, a preset smaller cutting depth and feed speed are used.

2. The laser-grinding combined machining method of micro-grooves of difficult-to-machine materials according to claim 1, characterized in that, In step S1: The micro-groove structure includes closed micro-grooves, semi-closed micro-grooves, and open micro-grooves; the design of the multi-process integrated special fixture is based on the processing surface and angle constraints of the micro-groove structure; the force characteristics in the process of laser non-contact processing and grinding contact processing are analyzed, and a modular design is adopted, including detachable or replaceable positioning elements, to meet the clamping requirements of different process characteristics, and a preset clamping force is set to ensure the inheritance of the positioning reference between processes and the stability of process connection.

3. The laser-grinding combined machining method of micro-grooves of difficult-to-machine materials according to claim 1, characterized in that, The types of lasers used include continuous lasers and pulsed lasers, and the pulsed lasers include millisecond lasers, nanosecond lasers, picosecond lasers, and femtosecond lasers. The processing methods used include mechanical scanning processing, galvanometer scanning processing, and rotary cutting processing. The scanning paths include linear reciprocating along the long side, sinusoidal along the long side, and linear reciprocating along the short side.

4. The laser-grinding combined machining method of micro-grooves of difficult-to-machine materials according to claim 1, characterized in that, The layered processing is as follows: the laser focal point is initially located on the upper surface of the workpiece, after completing one layer of scanning processing, the focal point moves downward by a preset distance along the depth direction, and the next layer of scanning processing begins, and this is repeated until the target bottom groove depth is reached.

5. The laser-grinding combined machining method of micro-grooves of difficult-to-machine materials according to claim 1, characterized in that, The step S4 of detecting the bottom groove and calculating the machining allowance of the target micro groove specifically comprises: In the clamped state of the workpiece and the fixture, the three-dimensional profile scanning of the bottom groove is performed by using the non-destructive testing technology, and the profile scanning result is used for the process optimization of step S3; the profile model of the bottom groove is reconstructed based on the scanning data, the model is compared with the theoretical model of the target micro groove, and the machining allowance of each region is calculated; the profile model of the bottom groove, the machining allowance data and the laser processing parameters of step S3 are associated, a prediction scheme of a hybrid architecture of a neural network and physical simulation is adopted, a mapping relationship database of the laser processing parameters-bottom groove profile and machining allowance is established, and the machining allowance can be directly obtained from the laser processing parameters after the accuracy of the database meets the requirements.

6. The laser-grinding combined machining method of micro-grooves of difficult-to-machine materials according to claim 1, characterized in that, The grinding processing used includes ordinary grinding processing and ultrasonic auxiliary grinding processing, the grinding tracks include linear reciprocating type along the long side, sinusoidal type along the long side, linear reciprocating type along the short side, and the grinding wheels used include electroplated grinding wheels, sintered grinding wheels and brazed grinding wheels.

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