Superhard material composite processing method based on laser ablation softening degree
By using laser ablation to soften superhard materials and combining it with mechanical grinding, the problem of high-efficiency machining of superhard materials has been solved, achieving efficient and precise machining results, reducing tool wear, and improving machining quality and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DONGHUA UNIV
- Filing Date
- 2026-03-23
- Publication Date
- 2026-05-15
AI Technical Summary
Superhard materials are difficult to machine efficiently and precisely. Traditional methods are inefficient, cause severe tool wear, and are difficult to control the heat-affected zone and surface quality.
Laser pretreatment is used to soften ultrahard materials. A softened layer is formed by nanosecond ultraviolet laser ablation. Combined with mechanical grinding, a quantitative index of laser ablation softening is introduced to design scientific grinding parameters.
It improved machining quality and precision, reduced machining resistance and tool wear, increased machining efficiency, and achieved scientific design of process parameters.
Smart Images
Figure CN122033713A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of laser-assisted precision machining and process optimization technology for superhard materials, and in particular to a method for composite machining of superhard materials based on laser ablation softening. Background Technology
[0002] Superhard materials, with their extremely high hardness, excellent wear resistance, superior thermal conductivity, and stable chemical inertness, demonstrate irreplaceable application value in modern high-end manufacturing. They are not only core materials for precision machining, high-performance cutting tools, and precision grinding tools, but also widely used in key component fields such as oil and gas drilling, optical device manufacturing, semiconductor processing, and aerospace, directly driving the development of advanced manufacturing technologies towards higher efficiency, higher precision, and longer lifespan.
[0003] However, the extreme properties of superhard materials present significant challenges in machining them. Their extremely high hardness and wear resistance result in very low efficiency and severe tool wear with traditional machining methods; while their chemical inertness and high thermal stability render many specialized machining methods based on chemical or thermal effects ineffective or with limited results. Current machining technologies for superhard materials often face a series of bottlenecks, including the difficulty of balancing machining efficiency and surface quality, challenges in controlling the heat-affected zone, and the susceptibility to microcracks and residual stress. This severely restricts the manufacturing capability, design freedom, and performance reliability of complex and precision parts made from superhard materials, becoming a key technological obstacle limiting their wider application. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a superhard material composite processing method based on laser ablation softening, thereby improving processing quality and precision, reducing processing resistance and tool wear, increasing processing efficiency, and realizing the scientific and quantitative design of process parameters.
[0005] The objective of this invention can be achieved through the following technical solutions: The invention lies in the synergistic effect of "laser pretreatment softening + mechanical precision excision".
[0006] This invention provides a method for composite processing of superhard materials based on laser ablation softening, comprising the following steps: S1. Based on the physical properties of the superhard material to be processed, determine the target softening index, and use a laser beam to scan and irradiate the predetermined processing area of the superhard material workpiece, so that the material in the predetermined processing area is ablated and softened to form a softened layer. S2. Define and obtain the quantitative index of laser ablation softening of the softened layer, wherein the laser ablation softening degree is a parameter used to represent the degree of softening of the material relative to the substrate; S3. Based on the laser ablation softening degree obtained in step S2, design the subsequent grinding process parameters for the softened layer of the superhard material to achieve the coordinated processing of laser pretreatment and mechanical grinding.
[0007] Furthermore, in step S2, the laser ablation softening degree is characterized by the following formula: Softening degree = (hardness of the matrix - average hardness after softening) / hardness of the matrix.
[0008] Furthermore, the specific method for obtaining the average hardness after softening is as follows: after precision polishing the surface of the softened layer formed by laser ablation, the Vickers indentation test method is used. Under the set test scheme, multiple indentation points are arranged in the influence area of the softened layer, the hardness value of each point is obtained, and then the average value is calculated.
[0009] Furthermore, the Vickers hardness calculation formula used in the Vickers indentation test is as follows: ,in, F The applied load is expressed in kgf. D The average length of the indentation diagonal is expressed in μm.
[0010] Furthermore, in step S2, a mapping relationship database between laser ablation process parameters and laser ablation softening degree is established in advance through experiments; based on the actual laser ablation process parameters used, the corresponding laser ablation softening degree is directly obtained from the database or calculated.
[0011] Furthermore, the experiment to establish the mapping relationship database includes: using a single-factor experiment to investigate the effects of laser scanning speed v, number of scans n, pulse frequency f, and laser power p on softening degree within a set parameter range.
[0012] Furthermore, in step S1, before the laser ablation experiment, the original surface of the superhard material sample is polished to reduce roughness.
[0013] Furthermore, in step S1, the laser beam is a nanosecond ultraviolet laser, and the irradiation path of the laser beam is pre-planned after the workpiece surface is precisely positioned and the contour coordinate information is obtained.
[0014] Furthermore, in step S3, the grinding process is an asynchronous process, that is, the laser ablation softening treatment and quantitative characterization of the overall processing path area are completed first in steps S1 and S2, and then the whole process is mechanically ground.
[0015] Furthermore, in step S3, the grinding process includes roughing, semi-finishing and finishing performed sequentially.
[0016] Compared with the prior art, the present invention has the following advantages: (1) Improve processing quality and precision. This invention softens the material through laser pretreatment, which can effectively reduce or avoid defects such as processing cracks and chipping that may occur in subsequent pure mechanical grinding, and can obtain a smoother surface, thereby improving the surface integrity and geometric accuracy of the final part.
[0017] (2) Reduced processing resistance and tool wear. After laser ablation softening, the hardness of superhard materials is significantly reduced, which greatly reduces the resistance of subsequent cutting or grinding. This not only reduces grinding force, but more importantly, it reduces the wear of tools (such as cutting tools and grinding wheels), significantly extending the service life of expensive superhard material tools, thereby improving the overall processing economy.
[0018] (3) Improved processing efficiency. Lasers can achieve localized, non-contact, rapid softening pretreatment, which, combined with precision material removal in machining, overcomes the bottleneck of low efficiency in traditional single machining. This process allows subsequent machining to be carried out at higher cutting speeds and depths, thereby achieving efficient removal of superhard materials and improving overall processing efficiency.
[0019] (4) Achieving scientific and quantitative design of process parameters. This scheme introduces the quantitative index of "laser ablation softening degree" to link the effect of laser pretreatment (material softening state) with the matching design of subsequent machining process parameters (such as grinding parameters). This changes the traditional experience-based process setting method, making the design of laser-assisted composite processing from pretreatment to posttreatment more scientific, precise and controllable, providing a theoretical basis and design method for achieving efficient, precise and collaborative processing. Attached Figure Description
[0020] Figure 1 This is a flowchart of a composite processing method for superhard materials based on laser ablation softening. Figure 2 The process and methods of laser experiments; Figure 3 This is a schematic diagram illustrating the working principle of an ultraviolet laser device. Figure 4 This is a schematic diagram of surface grinding after laser ablation; Figure 5 This is a schematic diagram of Vickers indentation. Detailed Implementation
[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.
[0022] Example 1 This embodiment provides a method for composite processing of superhard materials based on laser ablation softening, such as... Figure 1-5 As shown, it includes the following steps: S1. Based on the physical properties of the superhard material to be processed, determine the target softening index, and use a laser beam to scan and irradiate the predetermined processing area of the superhard material workpiece, so that the material in the predetermined processing area is ablated and softened to form a softened layer. S2. Define and obtain the quantitative index of laser ablation softening of the softened layer, wherein the laser ablation softening degree is a parameter used to represent the degree of softening of the material relative to the substrate; S3. Based on the laser ablation softening degree obtained in step S2, design the subsequent grinding process parameters for the softened layer of the superhard material to achieve the coordinated processing of laser pretreatment and mechanical grinding.
[0023] Example 2 This embodiment uses a nanosecond ultraviolet laser as the energy source for ablation processing, and tungsten carbide cemented carbide is selected as the hard material. For example... Figure 3 The laser diode in the pump source emits laser light of a specific wavelength, which is then focused onto the Nd:YVO4 crystal in the constant-temperature resonant cavity at 22°C after beam shaping, releasing coherent photons. Subsequently, the laser wavelength and frequency are changed by a frequency doubling crystal, and the laser light is reflected back and forth between the total reflection mirror and the output coupling mirror, and is amplified each time it passes through the Nd:YVO4 crystal. When the switch is turned on, the light in the resonant cavity is rapidly amplified and output from the output coupling mirror, forming a high-energy nanosecond pulse.
[0024] This embodiment provides a method for composite processing of superhard materials based on laser ablation softening, such as... Figure 1-5 As shown, it includes the following steps: S1. Based on the physical properties of the superhard material to be processed, determine the target softening index, and use a laser beam to scan and irradiate the predetermined processing area of the superhard material workpiece, so that the material in the predetermined processing area is ablated and softened to form a softened layer. Specifically: S11: Auxiliary positioning frame, which ablates a rectangular frame that precisely fits the bottom surface of the workpiece, and then focuses the laser beam on the surface of the workpiece to read the coordinate information of the workpiece surface; S12: Based on the obtained workpiece contour coordinates, plan the laser ablation path; S13: According to the planned pattern and path and the set laser experimental parameters, the upper surface of the workpiece is continuously scanned and ablated to obtain a micro-textured groove surface corresponding to the pattern. S2. Define and obtain the quantitative index of laser ablation softening of the softened layer, wherein the laser ablation softening degree is a parameter used to represent the degree of softening of the material relative to the substrate; S21: After precision polishing of the laser-ablated surface, Vickers indentation test is performed along the upper surface of the groove. The test plan is designed to set indentation points on one side of the V-groove to obtain hardness distribution data for quantitative analysis. S22: Organize the hardness values of each point in the affected area and calculate its average hardness. Compare the average hardness with the matrix hardness and calculate the softening degree at the corresponding location using the softening degree formula. S3. Based on the laser ablation softening degree obtained in step S2, design the subsequent grinding process parameters for the softened layer of the superhard material to achieve coordinated processing of laser pretreatment and mechanical grinding. For example... Figure 4 On a precision CNC grinding machine, the softened layer treated with laser ablation is subjected to layered grinding. The surface effects after grinding in the high-softening and low-softening areas are compared. In the high-softening areas, grinding is easier, and the material removal rate is significantly improved compared to the untreated baseline.
[0025] In specific implementation methods, such as Figure 2 In S1, firstly, based on the precise positioning of the auxiliary substrate and the laser ablation softening treatment, a laser beam is focused through a three-axis ultra-precision motion platform to ablate a rectangular frame that precisely fits the bottom surface of the workpiece; secondly, the workpiece is placed inside the frame, and the laser beam is precisely focused on the surface of the workpiece to obtain the coordinate information of the upper surface of the workpiece, and the distance between the laser ablation path and the edge of the workpiece is controlled to avoid abrupt changes in interaction that could affect subsequent experiments; finally, the laser experiment is carried out according to the preset scanning trajectory and experimental parameters.
[0026] The ultra-hard material workpiece is placed within a rectangular positioning frame on an aluminum substrate, ensuring complete fit. Subsequently, the laser focus is repositioned, and the laser scans and probes the edge feature points of the workpiece's upper surface at low power to accurately obtain the workpiece's actual position and contour coordinates in the motion platform coordinate system.
[0027] Based on the obtained workpiece contour coordinates, a laser ablation path is planned, and the distance between the ablation end and the edge is controlled to prevent burn-through and the edge groove depth from increasing.
[0028] In a specific implementation, the laser ablation softening degree in step S2 is characterized by the following formula: Softening degree = (hardness of the matrix - average hardness after softening) / hardness of the matrix.
[0029] In a specific implementation, the method for obtaining the average hardness after softening is as follows: after precision polishing the surface of the softened layer formed by laser ablation, the Vickers indentation test method is used. Under the set test scheme, multiple indentation points are arranged in the influence area of the softened layer, the hardness value of each point is obtained, and then the average value is calculated.
[0030] In the specific implementation, see Figure 5 A digital automatic turret Vickers hardness tester was used. Care was taken to control the spacing between the boundary indentations to avoid mutual interference. The Vickers hardness calculation formula used in the Vickers indentation test is as follows: ,in, F The applied load is expressed in kgf. D The average length of the indentation diagonal is expressed in μm.
[0031] In a specific implementation, in step S2, a mapping relationship database between laser ablation process parameters and laser ablation softening degree is established in advance through experiments; based on the actual laser ablation process parameters used, the corresponding laser ablation softening degree is directly obtained or calculated from the database.
[0032] In a specific implementation, the experiment to establish the mapping relationship database includes: using a single-factor experiment to investigate the effects of laser scanning speed v, number of scans n, pulse frequency f, and laser power p on softening degree within a set parameter range.
[0033] In a specific implementation, the grinding process in step S3 is an asynchronous process, that is, the laser ablation softening treatment and quantitative characterization of the overall processing path area are completed first in steps S1 and S2, and then the whole process is mechanically ground.
[0034] In a specific implementation, step S3 includes the grinding process consisting of roughing, semi-finishing, and finishing performed sequentially.
[0035] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.
[0036] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.
Claims
1. A method for processing superhard material composites based on laser ablation softening, characterized in that, Includes the following steps: S1. Based on the physical properties of the superhard material to be processed, determine the target softening index, and use a laser beam to scan and irradiate the predetermined processing area of the superhard material workpiece, so that the material in the predetermined processing area is ablated and softened to form a softened layer. S2. Define and obtain the quantitative index of laser ablation softening of the softened layer, wherein the laser ablation softening degree is a parameter used to represent the degree of softening of the material relative to the substrate; S3. Based on the laser ablation softening degree obtained in step S2, design the subsequent grinding process parameters for the softened layer of the superhard material to achieve the coordinated processing of laser pretreatment and mechanical grinding.
2. The method for composite processing of superhard materials based on laser ablation softening as described in claim 1, characterized in that, In step S2, the laser ablation softening degree is characterized by the following formula: Softening degree = (hardness of the matrix - average hardness after softening) / hardness of the matrix.
3. The method for composite processing of superhard materials based on laser ablation softening as described in claim 2, characterized in that, The specific method for obtaining the average hardness after softening is as follows: After precision polishing the surface of the softened layer formed by laser ablation, the Vickers indentation test method is used. Under the set test scheme, multiple indentation points are arranged in the influence area of the softened layer, the hardness value of each point is obtained, and then the average value is calculated.
4. The method for composite processing of superhard materials based on laser ablation softening as described in claim 3, characterized in that, The Vickers hardness calculation formula used in the Vickers indentation test is as follows: ,in, F The applied load is expressed in kgf. D The average length of the indentation diagonal is expressed in μm.
5. The method for composite processing of superhard materials based on laser ablation softening as described in claim 1, characterized in that, In step S2, a database of mapping relationships between laser ablation process parameters and laser ablation softening degree is established in advance through experiments; based on the actual laser ablation process parameters used, the corresponding laser ablation softening degree is directly obtained from the database or calculated.
6. The method for composite processing of superhard materials based on laser ablation softening as described in claim 5, characterized in that, The experiment to establish the mapping relationship database includes: using a single-factor experiment to investigate the effects of laser scanning speed v, number of scans n, pulse frequency f, and laser power p on softening degree within a set parameter range.
7. The method for composite processing of superhard materials based on laser ablation softening as described in claim 1, characterized in that, In step S1, before the laser ablation experiment, the original surface of the superhard material sample is polished to reduce its roughness.
8. The method for composite processing of superhard materials based on laser ablation softening as described in claim 1, characterized in that, In step S1, the laser beam is a nanosecond ultraviolet laser, and the irradiation path of the laser beam is pre-planned after the workpiece surface is accurately positioned and the contour coordinate information is obtained.
9. The method for composite processing of superhard materials based on laser ablation softening as described in claim 1, characterized in that, In step S3, the grinding process is an asynchronous process, that is, the laser ablation softening treatment and quantitative characterization of the overall processing path area are completed first in steps S1 and S2, and then the whole process is mechanically ground.
10. The method for composite processing of superhard materials based on laser ablation softening as described in claim 1, characterized in that, In step S3, the grinding process includes roughing, semi-finishing and finishing performed sequentially.