金刚石与磨料磨具工程

Research progress on abrasive geometry modeling and application

PENG Fei, ZHANG Yanbin, ZHANG Rukang, CUI Xin, XU Peiming, DONG Lan, ZHANG Xiaotian, SONG Xuelei, LI Changhe

2025, 45(4): 427-447. doi: 10.13394/j.cnki.jgszz.2024.0165

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Significance Abrasives are recognized as indispensable in precision machining, and their role in processing critical components has been firmly established. Geometric modeling of abrasives is regarded as essential for quantitative characterization of material removal, as it exerts substantial influence on the prediction of machining forces, thermal effects, and surface roughness. However, consistent guidance on modeling methodologies remains lacking, and controllable fabrication of abrasive geometries has persisted as a critical challenge requiring further investigation. Progress Abrasives are regarded as fundamental to precision machining and are considered essential for modeling material removal. In prior studies, abrasive geometries have typically been simplified as regular forms, such as spheres, cones, frustums, and truncated polyhedra. However, actual abrasives predominantly exhibit irregular polyhedral shapes, and their interaction mechanisms are not fully represented by these simplified models. To address this limitation, a random plane-cutting method has been developed on the basis of prior studies. In this method, realistic abrasive geometries are generated by intersecting regular shapes with randomly oriented planes, enabling quantitative analysis of material removal and surface roughness. Based on abrasive retention, abrasive machining is commonly categorized as fixed or free abrasive processing. In free abrasive machining, material is removed from the workpiece surface by free abrasives, primarily through lapping and polishing. By contrast, fixed abrasive machining is performed by fixing abrasives within a bond matrix. Although substantial differences exist between these methods in machining mechanisms, abrasive utilization, and fluid requirements, the accuracy of abrasive shape modeling has been shown to exert a significant influence on grinding force, heat generation, and surface roughness. Abrasive preparation is defined as a shape-forming process in which raw abrasives are processed into defined geometries, sizes, and properties to satisfy various industrial requirements. Grinding wheel dressing is recognized as a critical operation to maintain the profile, dimensional accuracy, and surface topography of the grinding wheel, and comprises two primary steps: truing and sharpening. Among these steps, micron-scale truing is conducted at the abrasive level, representing abrasive shaping. At present, abrasive shaping methods based on laser processing and thermochemical graphitization removal are regarded as major research focuses. Conclusions and Prospects Currently, abrasive geometries are primarily modelled as spheres, cones, frustums, and polyhedral. Abrasive modeling has been extensively applied in precision finishing processes utilizing both free and fixed abrasives. A range of abrasive manufacturing and shaping techniques has been investigated in recent studies, encompassing micro-mould replication, transfer-assisted screen printing, laser cutting, laser micro-structuring, and dressing methods based on the combined action of discharge heat and alternating cutting forces. A new perspective has been introduced through artificial intelligence-based abrasive modeling, and the development of intelligent systems integrating domain knowledge and data should be prioritized in future research. Furthermore, pixel-level recognition of multiple target abrasives in imaging data can be achieved through artificial intelligence algorithms. The integration of artificial intelligence with laser sintering and 3D printing is expected to enable precise fabrication of abrasives with controllable geometries. The implementation of online monitoring techniques facilitates accurate assessment of abrasive wear during machining, thereby providing data to support tool design and optimization.

Effect of heat treated tungsten interlayer on microcrystalline diamond coatings

WANG Hailong, DING Sheng, MA Li, WEI Qiuping

2025, 45(4): 448-457. doi: 10.13394/j.cnki.jgszz.2024.0063

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Objectives Microcrystalline diamond coatings have extremely high hardness and excellent wear resistance, but their application field is limited by poor tribological and binding properties. To improve the tribological properties of microcrystalline diamond coatings on cemented carbide substrates, tungsten metal is chosen as the interlayer material, and microscopic texture is constructed by heat treatment on the surface of the tungsten interlayer. Methods The evaporation method is used to deposit a tungsten interlayer on the surface of cemented carbide from which cobalt has been removed by an acid-base two-step method. The tungsten interlayer is then heat-treated in a reducing atmosphere with a certain proportion of argon and hydrogen gas mixture. After heat treatment for 30 minutes at various temperatures (700, 800, 900, 1 000 ℃), the effects of different heat treatment temperatures on the composition, morphology, and microstructure of the tungsten interlayer are studied using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Diamond coatings are deposited using the hot filament chemical vapor deposition (HFCVD) method on substrates without any treatment and on tungsten interlayers heat-treated at different temperatures. The substrate temperature is controlled at (800 ± 50) ℃, and the growth time is 6 hours. The morphology and quality of the diamond coatings are analyzed using SEM, X-ray diffraction, and laser Raman spectroscopy. Reciprocating friction and wear tester are conducted using Si₃N₄ ceramic balls against the diamond coatings for 120 minutes to evaluate the friction performance of each coating sample. Results The tungsten interlayer deposited by vapor deposition exhibits an amorphous structure, and its crystallinity significantly increases after heat treatment. Cracks are generated on the surface of the interlayer, forming "island - gully" structures of different sizes. The crystallinity of the tungsten interlayer after heat treatment at 700−800 ℃ is poor, with larger "island" and narrower “gullies” on the surface. The structure of the tungsten interlayer after heat treatment at 900 ℃ was more moderate, while the interlayer after heat treatment at 1 000 ℃ has the best crystallinity and the smallest "islands". SEM surface morphology, XRD patterns, and Raman spectroscopy show that the diamond grown on the substrate surface without a tungsten interlayer has the largest average grain size and uneven grain size distribution. The crystallinity and content of diamond coatings grown on tungsten interlayers after heat treatment are better, as reflected in the higher diffraction intensity of the diamond peak in the XRD spectrum and the narrower full width at half maximum (FWHM) of the diamond peak in the Raman spectrum. The grain size of diamond shows a trend of first decreasing and then increasing with rising heat treatment temperature, but in all cases is smaller than that of the sample without a tungsten interlayer. Rockwell indentation tests are conducted on each diamond-coated sample under a load of 600 N, and the indentation morphology is analyzed using scanning electron microscopy. The indentation results indicates that tungsten interlayers heat-treated at 700 and 800 ℃ do not significantly improve the bonding properties of the diamond coating, with both exhibiting HF6-grade bonding strength. In contrast, heat treatment at 900 and 1 000 ℃ effectively enhances the bonding properties of the diamond coating, with bonding strength grades reaching HF2 and HF1, respectively. The enhancement of bonding strength relies on the crystallinity of the tungsten interlayer and the formation of a good mechanical meshing effect due to the “island-gully” structure. Friction and wear results indicate that the diamond coating grown on the tungsten interlayer after 700 ℃ heat treatment has large drop. The coating grown on tungsten interlayers heat-treated at 800−1 000 ℃ ensures good bonding performance while improving friction performance to varying degrees. Among them, the diamond coating grown on the tungsten interlayer heat-treated at 900 ℃ has the smoothest wear mark, with an average friction coefficient as low as 0.062, and the corresponding Si₃N₄ friction pair has the smallest wear mark diameter and wear rate. Conclusions The tungsten interlayer and its “island-gully” structure after heat treatment can significantly improve the growth and crystal state of diamond, resulting in grain refinement and improved bonding and friction properties. The surface of the tungsten interlayer treated at 900 ℃ for 30 minutes produces a moderately sized “island-gully” structure and the best uniformity. The average grain size of the diamond coating grown on it is about 1.97 μm, with the lowest average friction coefficient, and the corresponding friction pair wear rate is only 19.2% of the sample without a tungsten interlayer. The bonding properties of diamond coating on tungsten interlayer after 1 000 ℃ heat-treated is significantly enhanced.

Plating process of diamond bimetallic layer

CHEN Leiying, CHEN Leiming, LIU Xueting, WANG Xulei, CHENG Shaokun, ZHU Ziyi, CHEN Boyu, JU Hengdong, PAN Xiaoyu, YAO Mengyuan

2025, 45(4): 458-469. doi: 10.13394/j.cnki.jgszz.2024.0098

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Objectives With the increasing demand for superhard tool performance in precision machining, the problems of weak bonding between diamond and metal interface, and high cost of controlling coating thickness urgently need to be solved. In this study, the molten salt plating process is adopted. The diamond surface is subjected to bimetallic synergistic modification treatment through the combination of four different metals, namely Ti-Ni, Ti-Mo, Ti-W and Ti-Co, in order to enhance the bonding force at the diamond/metal interface. Meanwhile, the influences of the differences in metal combinations on the coating are explored. Methods Four kinds of bimetallic modified diamond samples are prepared by the same molten salt plating process. The phase composition, the microscopic morphology, coating thickness and roughness of the samples are tested and analyzed to explore the influences of metal composition differences on the performance of diamond coatings. Taking the Ti-Ni plated sample as an example, its preparation process is as follows: (1) Under the conditions of NaCl mass fraction of 20.31%, KCl mass fraction of 25.84%, diamond mass fraction of 23.08%, titanium mass fraction of 7.69%, and nickel mass fraction of 23.08%, the masses of each raw material are weighed, and the mixture with a total mass of 3 g is placed in a burning boat. (2) The mixture is subjected to metallization plating treatment in a tubular furnace fully protected by argon gas. The plating temperature is 1 000 ℃, the holding time is 60 min, and the argon gas flow rate is 0.2 L/min. (3) After plating, the product is ultrasonically cleaned at 40 kHz for 30 minutes to remove the residual salt and the metal particles on its surface. Then, it is dried under vacuum at 60 ℃, ground and sieved to obtain the coated sample. Results (1) The thermodynamic stability and the interfacial compatibility of metal compounds affect the coating thickness. For the Ti-W modified diamond sample, due to the high stability of the Ti_xW_1−x compound, the low diffusion rate of W and the efficient reducing property of Ti-W, the maximum coating thickness is 3.4 μm. Due to the weak affinity of Ti-Co, the thinnest coating of the Ti-Co modified sample is 1.3 μm. Therefore, the coating thickness of the Ti-W sample is increased by 161.54% compared with that of the Ti-Co sample. Moreover, in the same sample, the thickness of the Ti-C layer formed by chemical bonding and the intermetallic compound layer varies greatly. The thickness difference between the Ti-C layer formed by chemical bonding and the intermetallic compound layer in the same sample is significant, with the former accounting for more than 79% of the thickness, while the physically deposited elemental metal layer is thinner. Therefore, the synergistic effect of the Ti-C covalent bond dominated by chemical bonding and the intermetallic compound interface structure with the metal layer assisted by physical deposition can effectively coordinate the interfacial stress and improve the bonding stability of the coating. (2) The lattice mismatch between metals affects the surface roughness R_a of bimetallic modified diamond. Low mismatch Ti-Mo (with mismatch degree of 0.064 6) and Ti-W (with mismatch degree of 0.070 7) bimetallic modified diamonds exhibit better surface quality on the (111) crystal plane, with R_a values of 17.021 and 15.341 nm, respectively, which are 12.41% and 21.05% lower than those of Ti-Ni (with mismatch degree of 0.193 8) bimetallic modified diamond, and 57.16% and 61.39% lower than those of Ti-Co (with mismatch degree of 0.151 8) bimetallic modified diamond, respectively. This is due to the regulatory effect of lattice compatibility on the interfacial bonding strength, which in turn affects the surface morphology of the coating. The mismatch degree between Ti-Co is lower than that between Ti-Ni, but its roughness is actually higher, which is related to the surface protrusions on the coating surface caused by the accumulation of cobalt elements during the deposition process. Conclusions The use of the molten salt method for bimetallic modification of diamond successfully triggers the interfacial chemical reaction between diamond and metal, transforming the bonding mode from single physical coating to a comprehensive combination of chemical bonding and physical coating. This significantly enhances the interfacial bonding strength of diamond/metal, providing a reference for the experimental optimization of high-performance diamond tools.

Analysis of microstructure and properties of laser cladding diamond alloy coating on 45 steel surface

LU Tian, WANG Chuanliu, MA Shaoming, ZHU Ying

2025, 45(4): 470-478. doi: 10.13394/j.cnki.jgszz.2024.0100

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Objectives To significantly enhance the surface wear resistance of 45 steel under high friction and high-load conditions, a new type of wear-resistant alloy coating with high hardness and strong adhesion is constructed on its surface using laser cladding technology. The coating is mainly composed of nickel-plated diamond as the wear-resistant phase, and high-melting-point ceramics such as WC and TiC as the reinforcing phases. Meanwhile, the microstructure and fluidity of the coating are improved by adding metal elements such as Ti and Co. The focus is on studying the influence of laser power on the graphitization of diamond and the metallurgical bonding quality with the substrate during the laser cladding process, thereby optimizing the process parameters and improving the comprehensive performances of the coating. Methods A multi-component alloy wear-resistant coating is prepared on the surface of 45 steel by the laser cladding process. The coating formula contains a certain proportion of nickel-plated diamond, WC, TiC, Ti and Co powders. The influence of adjusting the laser power on the structural stability of diamond particles, the interface bonding state and the overall microstructure morphology is investigated. After cladding, the microstructure of the coating is observed by metallographic microscope (OM) and scanning electron microscope (SEM) respectively, and the elemental distribution is analyzed by energy dispersive spectroscopy (EDS). Moreover, the microhardness of the coating is tested using a Vickers hardness tester, thereby comprehensively evaluating the performance of the coating. Results The laser power has a significant impact on the stability of the diamond structure during the coating formation process. Under appropriate laser power, the nickel-plated diamond particles do not exhibit significant graphitization during the melting process, and the particles remain intact and form a good metallurgical bond with the metal substrate. On the contrary, excessive laser power can cause some diamond particles to undergo graphitization, thereby affecting the performance of the coating. The introduction of WC and TiC reinforcing phases can effectively absorb some of the laser energy, reduce the thermal shock on the diamond surfaces, suppress their ablation and graphitization, while promoting the formation of fine-grained microstructures, improving the structural stability and wear resistance of the coating. In addition, the addition of Co and Ti elements significantly improves the wettability of the molten pool metal and the fluidity of the coating, enhances the bonding strength between the alloy coating and the ceramic particles, and effectively improves the uniformity and density of the coating. The internal structure of the alloy coating is uniform, without obvious cracks or delamination. The diamond particles are densely distributed and the interfaces are tightly bonded. The average hardness of the coating reaches HV 257.85, which is approximately 51% higher than HV 170.40 of the base 45 steel. Therefore, the hardness enhancement effect is remarkable. Conclusions By optimizing the laser cladding parameters and reasonably designing the alloy powder system, the nickel-plated diamond and the reinforcing phases such as WC and TiC can synergistically work under high-temperature laser cladding conditions, effectively improving the density of the coating structure, the stability of the diamond structure, and its adhesion with the substrate. The prepared alloy wear-resistant coating significantly improves the microhardness and the wear resistance of the 45 steel surface, and has good interfacial bonding and thermal stability, making it an ideal material for improving the wear resistance and service life of 45 steel.

Study on performance of brazed micronized diamond grinding head

LI Wei, XIAO Bing, HE Xu, ZHANG Zili, ZHOU Lulu, XIAO Haozhong

2025, 45(4): 479-485. doi: 10.13394/j.cnki.jgszz.2024.0025

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Objectives The use of brazing micro-powder diamond tools can achieve high-precision and efficient processing of ceramic materials. However, there are currently problems such as thin brazing layers, large abrasive damage during brazing, and poor bonding between the brazing material and the base metal. Current research has not been able to analyze the brazing effect from the micro-interface. Methods Brazing samples are prepared, and the surface morphology and the morphology of diamond abrasive particles and surface products are observed with a scanning electron microscope (SEM). The phases of the compounds on diamond are analyzed with an X-ray diffractometer. The cross-sectional structure of the brazing samples are observed with the backscattered electron imaging mode of SEM. The elemental composition of the bonding interface of the brazing samples is analyzed with an energy dispersive spectrometer (EDS). A grinding head is prepared to machine an alumina ceramic plate on a JDHGT type engraving machine, and it is compared with an electroplated grinding head. Results The exposure height of the micro-diamond abrasive is reasonable with no accumulation. The diamond is not over-consumed, and a plate-like Cr₃C₂ is generated on the diamond surface. There is sufficient elemental diffusion between the brazing alloy and the base metal. Products at the interface between the steel substrate and the brazing alloy are a γ-phase solid solution formed by Cr and Fe, and a Ni-Fe substitutional solid solution by Fe and Ni, which ensures a firm combination between the brazing alloy and the base metal. Conclusions The life of the brazed micro-diamond head is three times longer than that of the electroplated grinding head. The situation of abrasive particle breakage and shedding in the brazed grinding head is less, and there is no phenomenon of brazing alloy layer peeling. This proves that the brazing effect of micro-diamond is better, and the method of processing ceramics with brazed micro-diamond tools is feasible.

Ultra-low temperature grinding process and surface integrity of SiCp/Al material

GUO Weicheng, HAN Shaojie, HE Qichao, GUO Miaoxian

2025, 45(4): 486-495. doi: 10.13394/j.cnki.jgszz.2024.0129

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Objectives As a new-generation high-performance structural material, silicon carbide particle-reinforced aluminum matrix composites (SiCp/Al) exhibit outstanding specific strength, wear resistance, and thermal stability, making them highly valuable in aerospace precision components, electronic packaging substrates, and other advanced manufacturing fields. However, common machining-induced damage issues such as matrix smearing and particle fragmentation severely compromise surface integrity and service performance. This study focuses on 20% SiCp/Al composites, systematically investigating the effects of process parameters on grinding force evolution, surface damage mechanisms, and surface integrity by comparing liquid nitrogen ultra-low temperature and room temperature air-cooling grinding conditions. The aim is to reveal the regulatory mechanisms of ultra-low temperature environments on composite machining performance and provide theoretical guidance for precision process optimization. Methods Grinding experiments are conducted on 20% SiCp/Al composites using diamond grinding wheels under single-factor conditions. The ultra-low temperature grinding experiments are performed on a vertical machining center with internal liquid nitrogen jet cooling, while conventional room temperature air-cooling serves as the control group. Process parameters includes wheel speed 2.04 to 2.98 m/s, feed rate 50 to 200 mm/min, grinding depth 5 to 20 μm, and grinding width 6 mm. A dynamometer monitored normal and tangential grinding forces in real time. Surface roughness is measured via white light interferometry, residual stress measured via X-ray diffraction analysis, and microhardness measured via a microhardness tester. Surface and subsurface damage is characterized using scanning electron microscopy. Results (1) Under both cooling conditions, grinding forces decreases with increased wheel speed and increases linearly with feed rate and grinding depth. The ultra-low temperature environment significantly enhances material yield strength and interfacial bonding strength, resulting in average grinding forces 1.7 to 2.7 times higher than those under room temperature air-cooling conditions. While room temperature grinding forces shows minor variations with parameter changes, wheel speed and feed rate exerts substantial impacts in ultra-low temperature grinding. (2) Grinding-induced damage in SiCp/Al primarily manifests as matrix smearing/tearing and SiC particle fracture/pullout. Despite higher grinding forces under ultra-low temperature conditions, surface damage is consistently less severe than under room temperature cooling. In ultra-low temperature grinding, reduced thermal effects and increased material strength/hardness promotes localized stress concentration, leading to minor matrix smearing and particle fracture. In contrast, room temperature grinding induces extensive matrix tearing, particle pullout, and associated cracks/pits. (3) Ultra-low temperature grinding effectively suppresses matrix smearing, pits, and crack propagation, achieving surface roughness values 16% to 42% lower than those under room temperature air-cooling conditions. Higher grinding forces under ultra-low temperature conditions enhances plastic deformation strengthening, while liquid nitrogen cooling minimizes thermal softening effects. Consequently, ultra-low temperature grinding generates larger residual compressive stress magnitudes and higher surface microhardness compared to room temperature grinding. Conclusions The liquid nitrogen ultra-low temperature environment significantly improves the mechanical properties of the SiCp/Al matrix and interfaces through cryogenic strengthening. Although grinding forces increase, this approach effectively suppresses machining damage, substantially reduces surface roughness, and generates enhanced residual compressive stress fields and uniform hardened layers. The influence of process parameters on grinding forces and surface integrity follows similar trends under both cooling conditions. Optimal parameter combinations with higher wheel speeds and smaller depths of cut enable efficient, low-damage machining. The transition in damage mechanisms and improvements in surface integrity validate that ultra-low temperature environments optimize material removal processes through thermo-mechanical coupling suppression and mechanical property enhancement, offering a novel pathway for precision machining of particle-reinforced composites.

Ultra-precision machining test of diamond sand belt for Si₃N₄ ceramic cylindrical roller

WANG Hongliang, LI Songhua, JIN Chi, TIAN Kai, GUO Hao, ZHAO Zichen

2025, 45(4): 496-503. doi: 10.13394/j.cnki.jgszz.2024.0106

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Objectives Si₃N₄ ceramic cylindrical rollers show excellent service performance in extreme working conditions, but their hardness and brittleness and other characteristics lead to difficulties in machining. To realize high-quality and highly flexible machining and manufacturing of Si₃N₄ ceramic cylindrical rollers, a diamond abrasive belt super-finishing machining method for Si₃N₄ ceramic cylindrical rollers is proposed. Methods By building an ultra precision machining experimental platform with a diamond abrasive belt, designing orthogonal experiments, and conducting horizontal response analysis and ANOVA on the experimental data, the influences of abrasive particle size in the diamond abrasive belt, abrasive belt linear velocity, abrasive belt pressure and guide roller speed on the surface roughness R_a and the material removal rate R_MRR of Si₃N₄ ceramic cylindrical roller workpieces (ϕ 10 mm × 12 mm) are studied. Results The effects of abrasive grain size in the diamond abrasive belt on both surface roughness and material removal rate of the workpiece are the most significant. The effects of diamond abrasive belt pressure on the surface roughness of the workpiece are larger compared to those of diamond abrasive belt linear speed and guide roller rotational speed, while the effects of diamond abrasive belt linear speed on material removal rate are larger compared to those of diamond abrasive belt pressure and guide roller rotational speed. The minimum value of surface roughness of the workpiece is 0.0452 μm when the grain size code of the diamond belt is P3000, the linear speed of the diamond belt is 10 m/s, the pressure of the diamond belt is 94 N, and the rotational speed of the guide roller is 300 r/min; the minimum surface roughness of the workpiece is also 0.045 2 μm when the grain size code of the diamond belt is P2000, the linear speed of the diamond belt is 20 m/s, the pressure of the diamond belt is 94 N, the rotational speed of the guide roller is 200 r/min. When the rotational speed is 200 r/min, the maximum material removal rate is 1.075 31 μm/min. Conclusions The surface quality of Si₃N₄ ceramic cylindrical rollers can be effectively improved by using the superfinishing method with a diamond abrasive belt.

Advance on molecular dynamics simulations of precision polishing of SiC

ZHANG Jiayu, MENG Erchao, SUN Jianlin, JI Jianzhong

2025, 45(4): 504-516. doi: 10.13394/j.cnki.jgszz.2024.0070

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Significance Silicon carbide (SiC), as a representative material of third-generation semiconductors, holds vast potential for applications in microelectronics, optoelectronics, aerospace, and energy. However, its high hardness and chemical stability pose significant challenges for processing. Chemical mechanical polishing (CMP) is a crucial technology for planarizing SiC substrates. It can effectively remove the damaged layer and impurities on the wafer surface, achieve a high degree of planarization, thereby enhance the performance and reliability of SiC devices. Extensive research has been conducted on CMP processes, yet the mechanisms of interaction and synergy among abrasives, solution media, and SiC surfaces remain unclear. Molecular dynamics (MD) simulation, based on Newton's laws of motion and the principles of quantum mechanics, is a simulation method used to reveal the interactions between the microscopic structure and properties of matter. It is currently widely applied in the study of SiC surface removal mechanisms. By simulating the scratching behavior of abrasives on SiC surfaces, changes in material morphology, crystal structure, temperature, cutting force, and potential energy can be observed, thereby providing deeper insights into polishing mechanisms. This in-depth understanding of polishing mechanisms aids in optimizing polishing process parameters, improving polishing efficiency, and surface quality. Meanwhile, during the SiC CMP process, certain components in the polishing solution interact with the SiC surface, potentially involving a series of chemical reactions. MD simulation can reveal the detailed mechanisms of these chemical reactions, including the reaction pathways, reaction rates, and reaction products, thereby facilitating a deeper understanding of the material removal mechanism during the polishing process and providing a theoretical basis for optimizing polishing processes. Progress The article first analyzes the potential functions commonly used in MD simulations for SiC precision polishing and summarizes their application fields. It then integrates and analyzes existing MD simulation studies on SiC CMP. MD simulations for SiC substrate precision polishing are mainly classified into three categories: SiC material properties, abrasive grinding, and SiC surface chemical reactions. The Tersoff potential function has been widely applied in the preparation and properties of SiC materials, demonstrating excellent simulation results. It has become the most popular potential function for MD simulations of SiC materials. The Tersoff / ZBL potential function enhances the Tersoff potential function by incorporating the ZBL potential, thus adding short-range interactions and providing a more accurate description of short-range atomic collisions. The ABOP potential function, based on the Tersoff potential function, allows for the breaking of chemical bonds, making it more suitable for simulating wear behavior. The Vashishta potential function is well-suited for accurately simulating the deformation of ionic and covalent bonds in 3C-SiC, including bending and stretching. It is widely used in simulations involving impact behavior and nanoindentation of SiC. The advantage of the ReaxFF lies in its ability to simulate the formation and breaking of bonds during chemical reactions, making it suitable for simulating chemical reactions, adsorption, and other phenomena on SiC surfaces. Conclusions and Prospects Currently, many aspects of the CMP mechanism of SiC materials remain unclear. MD simulations can be utilized to study the interaction mechanisms between liquids, oxides, and surfaces during CMP, such as charge transfer and surface adsorption. Most research has focused on the mechanical interactions between abrasives and SiC surfaces, with relatively little attention paid to chemical reaction mechanisms. Future research will emphasize using the ReaxFF through MD simulations to study the reaction mechanism of SiC under various conditions, developing more potential functions to accommodate different polishing conditions, and establishing comprehensive models to consider the impact of multiple factors on surface interactions. During MD simulations of SiC oxidation mechanisms, different potential functions have distinct application fields. Although the ReaxFF reactive force field can effectively simulate SiC surface oxidation reactions, using the Tersoff potential function to simulate the interaction between SiC and abrasives is more reasonable. Due to the high modeling proficiency required to establish mixed potential function models combining the ReaxFF reactive force field with other potential functions, researchers often adopt the ReaxFF single intermolecular potential for calculations. If oxidation reactions and abrasive grinding occur simultaneously during the calculation process, it may not accurately describe the SiC surface interaction mechanisms. Therefore, combining the ReaxFF with other potential functions to achieve MD simulation of chemical mechanical polishing under the combined action of multiple factors will be a direction for future research.

Research on preparation of adhesive magnetic polishing abrasives and polishing performance

WANG Xuanping, GUO Yiao, PENG Can, YU Yang

2025, 45(4): 517-525. doi: 10.13394/j.cnki.jgszz.2024.0077

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Objectives With the increasing demand for parts with complex shapes and fine structures in high-end equipment, the requirements for finishing precision and surface quality are becoming more stringent. Magnetic polishing technology relies on magnetic fields to drive magnetic abrasives to move relative to the parts, allowing for simultaneous polishing of multiple complex parts. It is an effective method for achieving high-quality and efficient finishing of parts with complex shapes and fine structures. Magnetic abrasives serve as the "cutting tools" in magnetic polishing, and their preparation is a key technology in this process. Magnetic abrasives prepared by sintering, bonding, and atomization methods possess good polishing effects, however, they need be crushed into powdery particles for use, which causes inconvenience in magnetic polishing. Research on the preparation of magnetic abrasives is therefore indispensable to meet the demands of high-performance polishing. Methods To enhance the performance of magnetic polishing, a slender bonded magnetic abrasive is designed, where carbonyl iron powders are adopted as the magnetic phase and silicon carbide are adopted as the abrasive phase. The two-phase materials are bonded with resin chemicals, and bonding strength is enhanced through chemical modification using a coupling agent. The movement patterns and material removal mechanisms of the prepared magnetic abrasives are analyzed to explore their differences from conventional stainless-steel magnetic needles. The differences in scratch behavior at the micro level are experimentally studied using aluminum alloy samples, and the impact on polishing quality is studied. Preparation of magnetic polishing abrasives: First, carbonyl or silicon carbide powders are separately added into a 0.1 g/mL dilute NaOH solution in a beaker, fully submerged, and stirred at constant temperature, then washed with anhydrous ethanol until neutral and dried. Second, the treated carbonyl iron powders or silicon carbide powders are placed in a beaker, a silane coupling agent KH-560 is added, and the mixture is processed in a water bath to obtain dried powders. Third, the above-modified carbonyl iron powders and silicon carbide powders are weighed and mixed in a predetermined mass ratio, and stirred for 6 hours to solve the problem of uneven powder agglomeration. Finally, a predetermined ratio of epoxy resin is added to the mixed inorganic powders, and slender magnetic abrasives with a diameter of 2-3 mm and a length of 6-8 mm are obtained through extrusion molding, followed by a 24 h curing treatment at room temperature. Results A study is conducted on the material removal effect of magnetic abrasives. The polishing effects of workpiece surfaces using magnetic needles and magnetic abrasives are compared. The elasticity of the bonded magnetic abrasives is significantly higher than that of magnetic needles, resulting in a weaker impact on workpieces, with polishing mainly achieved by the embedded silicon carbide abrasives. To facilitate observation of scratches in magnetic polishing, 6061 aluminum alloy workpieces with an initial surface roughness of S_a 4 nm are adopted for magnetic polishing experiments, for exploration of differences in polishing between magnetic needles and elastic magnetic abrasives. With magnetic needles, the surface texture caused by the superposition of pits formed by needle impact tends to stablilize after 30 min of polishing, achieving a surface roughness of S_a 1.418 μm. With magnetic abrasives, the surface texture caused by abrasive scratches tends to stabilize after 20 min of polishing, achieving a surface roughness of S_a 0.318 μm. Conclusions A preparation method is proposed for the fabrication of slender, elastic magnetic abrasives. Material removal mechanisms and surface morphology formation are analyzed, and experiments on 6061 aluminum alloy workpieces are carried out to compare conventional magnetic needles with the slender magnetic abrasives. The results show that elastic magnetic abrasives possess higher polishing efficiency and achieve better polishing effects than magnetic needles for metal materials such as 6061 aluminum alloy.

Effect of double-sided polishing on surface morphology of quartz mask blanks

ZHANG Cheng, QIN Rui, BAI Jihao

2025, 45(4): 526-533. doi: 10.13394/j.cnki.jgszz.2024.0161

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Objectives As the critical dimensions in integrated circuit structures continue to shrink, transistor density and chip performance keep improving. At the same time, the continuous evolution of integrated circuit manufacturing processes increasingly demands stricter flatness requirements for mask blanks. To reveal the polishing removal mechanism of double-sided chemical mechanical polishing on quartz mask substrates, a polishing solution is made using CeO₂ abrasive to perform double-sided polishing on 6025 quartz mask substrates. Methods (1) CeO₂ polishing powders with particle size distributions D₅₀ of 0.823 and 1.231 μm respectively are placed in a beaker with deionized water. Under mechanical stirring, a certain amount of a mixture of sodium hexametaphosphate and sodium citrate is added as a dispersant, and an appropriate amount of polyacrylate as a surfactant. The pH value is adjusted using a weak alkali substance. Based on the content of CeO₂, polishing liquids with mass fractions of 6%, 10%, 14%, and 18% are prepared. (2) The CMP experiment is conducted on a 22B double-sided polisher using an LP66 polyurethane polishing pad to polish 6025 synthetic quartz substrate grinding discs. The same set of polishing parameters is used to polish 12 pieces of 6025 simultaneously, and then the flatness and roughness of the 12 pieces of glass are averaged. For the polishing slurry, experiments are conducted with two types of polishing powder particle sizes and four types of polishing slurry concentrations. The surface morphology of different particle size CeO₂ polishing powders is observed using a Zeiss Sigma field emission scanning electron microscope. The particle size distribution of the polishing powders is analyzed using a Mastersize 2000 laser particle size analyzer. The flatness of the quartz substrates before and after polishing is measured using a Tropel® UltraFlat™ flatness tester from CORNING. The change in thickness of the quartz substrates before and after polishing is measured using a KEYENCE displacement sensor to calculate the polishing rate. The roughness of the quartz substrates after polishing is measured using a Dimension ICON atomic force microscope from Bruker Germany. Results The flatness can reach 0.573 μm, and the surface roughness R_a is 0.96 nm under the following conditions: equivalent particle size D₅₀ of CeO₂ 0.823 μm, mass fraction of CeO₂ 14%, polishing pressure 0.43 MPa, and a gear ring and sun gear speed of 6.54 and 3.08 r/min, respectively. Conclusions (1) The surface roughness of quartz glass after polishing with fine-grained 230A is reduced by 40% compared to that after polishing with 1200A. (2) With the increase in the concentration of the polishing solution, the flatness of the front surface initially shows a decreasing trend. It reaches a minimum value at a mass fraction of 14%. However, if the concentration is further increased, the flatness actually increases. The removal rate of the quartz glass increases continuously with the concentration of the polishing solution. (3) As the polishing pressure increases within the range of 0.26-0.43 MPa, the removal rate basically changes linearly. However, if the pressure is further increased, the removal rate actually decreases. (4) Using abrasive particles with an equivalent diameter D₅₀ of 0.823 μm, a polishing solution with a concentration of 14% CeO₂ is prepared. Under a polishing pressure of 0.43 MPa, and a ring gear and sun gear speed of 6.54 and 3.08 r/min, respectively, the surface of the 6025 quartz glass is polished to be smooth with almost no scratches or median cracks, achieving smaller flatness and better surface quality.

Design and performance of compliant grinding tools for blade root smooth grinding

LI Mingcong, TIAN Peisen, HUANG Yun, YAN Shengbo, ZOU Lai, WANG Wenxi

2025, 45(4): 534-541. doi: 10.13394/j.cnki.jgszz.2024.0059

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Abstract:
Objectives The difficulty in machining complex structural components such as aircraft engine blade roots is a common problem in the precision machining industry, and the stability of grinding tool performance is crucial for achieving automated machining. In a narrow processing space, due to the poor thermal stability of flexible materials themselves, the accumulation of grinding heat can reduce the service life and grinding performance of the grinding tool, becoming a key factor in the decrease of precision in automated processing of complex structural components. Therefore, an enhanced blade heat conduction structure is introduced into the ball-end grinding tool to improve the heat conduction performance of the grinding tool and increase its service life and application performance. Methods Through fluid dynamics simulation, the influences of the rotation direction, the rotation speed of the grinding tool, and the flow rate of external cold air on the flow field, temperature field, pressure field of the grinding tool are studied. A flexible grinding tool substrate with a complex internal structure is prepared using multi-layer melt spraying technology, and an adhesive grinding tool with a sandwich structure is designed to ensure precise and tight adhesion between the abrasive layer and the ball-head grinding tool substrate. The processing trajectory programmed by industrial robots is adopted to conduct an automated processing of titanium alloy plates for 200 s. The grinding performance differences between the designed grinding tools and the traditional structural grinding tools are compared through indicators such as grinding temperature, surface roughness, and cumulative material removal depth. Meanwhile, through the analysis of the microscopic morphology of the grinding surface of titanium alloy and the wear of the grinding tool, the internal mechanism of the designed grinding tool in improving the continuous grinding performance is clarified. Results When the grinding tool with an enhanced heat transfer mechanism rotates counterclockwise, the external fluid is introduced into the inner cavity of the grinding tool, forming a significant vortex. Meanwhile, the blade structure helps enhance the convection of gas in the inner cavity to achieve heat exchange. Moreover, the external fluid is blown at high speed towards the cavity near the outer side of the inner wall, forming a high-pressure area, which further promotes heat transfer. The grinding tools with an internal blade structure have a stronger cooling capacity at higher rotational speeds, and the surface temperature is lower than 170 ℃ when the rotational speed is 14000 r/min. However, the cooling effect of the grinding tools with traditional structures is relatively weak as the rotational speed increases. When the rotational speed is 14000 r/min, the surface temperature is still higher than 180 ℃. As the flow of external cold air increases, more cold air is drawn into the interior of the grinding tool blade structure, bringing a stronger heat transfer effect, improving the cooling utilization rate and reducing the temperature of the grinding tool. The grinding temperature of traditional solid-structured grinding tools is the highest, exceeding 140 ℃ between 55 and 100 s. The strong accumulation of local grinding heat causes the flexible material to melt and adhere to the surface of the grinding tool, hindering its material removal. Therefore, the material removal capacity of traditional solid-structured grinding tools drops sharply after 140 s. In addition, there are significant fluctuations in the surface roughness of the workpiece grinding. The annular adhesion phenomena are observed on the surface of traditional structural grinding tools. The main failure mode of the internal blade structure grinding tool is the stripping of the abrasive layer. Its enhanced heat conduction structure can effectively achieve heat exchange between cold air and local high temperature in the grinding area, thereby alleviating the adhesion of the flexible substrate. Conclusions The formation, propagation and dissipation of vortices inside the grinding tool promote the improvement of heat conduction efficiency, thereby enabling the designed flexible grinding tool to achieve higher heat conduction performance and grinding effect. In addition, as the grinding speed increases, the temperature uniformity on the surface and inside the grinding tool is improved. The grinding tools with an internal blade structure maintain a relatively stable grinding temperature and material removal capacity during continuous grinding, as well as good surface quality of the workpiece.

Dual camera testing method for 3D velocity field of rolling and grinding blocks

TIAN Chunyue, DING Junfei, LI Wenhui, LI Xiuhong, YANG Shengqiang

2025, 45(4): 542-550. doi: 10.13394/j.cnki.jgszz.2024.0014

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Objectives The motion speed of the rolling and polishing block is one of the key factors affecting the overall machining effect of rolling polishing. However, the traditional method for measuring the flow velocity of rolling and polishing blocks has many shortcomings, especially in terms of testing accuracy and efficiency. The traditional method often cannot directly obtain velocity data and is limited by single-point testing, which cannot comprehensively and dynamically reflect the motion trajectory of the rolling and polishing block flow field. In addition, the interference of the measurement process with the flow field of the rolling and polishing block is also a factor that cannot be ignored in the testing process of the traditional method, and it significantly affects the accuracy of the test results. Therefore, a dual-camera testing method for the three-dimensional velocity field of the rolling and polishing block is proposed, aiming to achieve accurate measurement of the motion velocity of the rolling polishing block through this method and further improve the effect and accuracy of rolling polishing machining. Methods Two Dushen industrial cameras are used to synchronously capture motion images of the rolling polishing block from different perspectives, and then the motion trajectory of the rolling polishing block in three-dimensional space is constructed using disparity calculation and feature point tracking algorithms. The specific process is as follows: First, the position changes of the surface feature points of the rolling grinding block are extracted through the image matching algorithm. Then, by using the calibration parameters of the camera (including internal parameters, external parameters, and distortion coefficients), the two-dimensional image coordinates are mapped to the three-dimensional coordinate system to complete the calculation of the velocity vector. Next, a three-dimensional velocity field test system for the rolling and polishing grinding block are established, and the accuracy and stability of the system are be verified through displacement test experiments. The three-dimensional velocity field test of the vertical vibration roller grinding and finishing processing equipment is conducted on the roller grinding blocks to verify its application feasibility and stability in actual processing, and to further evaluate its performance and advantages in roller grinding and finishing processing. Results The displacement test results show that the displacement values measured by the testing system are very close to the actual applied displacement values. In the X direction, the absolute value of the average measurement error is less than 0.10 mm. In the Z direction, the absolute value of the average measurement error is less than 0.15 mm. The three-dimensional velocity field test experiment of the rolling polishing block reveals the motion law of the flow field of the rolling polishing block. The measured three-dimensional velocity field of the rolling polishing block is basically consistent with its actual motion law, verifying the effectiveness and accuracy of this testing method in measuring the velocity of the rolling polishing block. Moreover, it can accurately capture the motion trajectory without interfering with the flow field, providing reliable motion analysis data for the grinding and finishing process. Conclusions The proposed dual camera testing method for the three-dimensional velocity field of rolling polishing blocks provides a new technical approach for measuring the three-dimensional velocity field of rolling polishing blocks. This method can accurately and stably obtain the three-dimensional velocity field of rolling polishing blocks and reveal their motion laws, providing an effective tool for further optimizing the rolling polishing process. This testing system is expected to play a greater role in high-precision motion analysis and machining optimization, providing assistance for other similar complex flow field tests.

Prediction model of robot grinding and polishing contact force based on EWOA-LSSVR

ZHANG Shihan, WEI Jinhui, WANG Yang, ZHU Guang, LI Lun, LIU Dianhai

2025, 45(4): 551-560. doi: 10.13394/j.cnki.jgszz.2024.0089

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Objectives High-pressure turbine blades, as the core components of aviation engines, are subjected to harsh working environments of high temperature, high pressure, and high load for a long time, which places strict requirements on their high-temperature mechanical properties and structural stability. Therefore, the material of turbine blades is often selected as single-crystal high-temperature alloys and the blades are made through precision casting processes. Due to the casting characteristics of the blades, the material distribution of the workpiece is uneven, that is, the deviations of the design sizes from different positions on the blade surfaces vary. Therefore, the fixed-point quantitative removal of the blade surface material plays a very important role in the blade production and manufacturing process. Methods Blade grinding and polishing processing experiments are established by considering various technological parameters. The experimental data are used as the training set for the prediction model, and a prediction model based on the least squares support vector machine (LSSVR) is constructed. In the LSSVR hyperparameter setting stage, the enhanced whale optimization algorithm (EWOA) is used to improve algorithm accuracy, enhance optimization capability, and prevent local optima while optimizing the LSSVR hyperparameters. The prediction models optimized by other algorithms are established for comparison of model prediction capabilities. The prediction results are applied to the reproduction experiments of the material removal amount, and the performance of the prediction model is evaluated by using the processing results. Results From the perspective of model establishment and result prediction, the processing parameter prediction model EWOA-LSSVR based on the enhanced whale optimization algorithm (EWOA)-optimized least squares support vector machine (LSSVR) exhibits high prediction accuracy and good model fitting degree, with a determination coefficient of 96.031% and a mean absolute error R_MAE of 0.012 128 mm. The prediction models of LSSVR optimized by the whale optimization algorithm (WOA) and particle swarm optimization (PSO) have determination coefficients of 89.457% and 92.228%, and mean absolute errors (R_MAE) of 0.012 358 and 0.012 462 mm, respectively. In contrast, the prediction results of EWOA-LSSVR are more accurate with lower errors. The prediction results of EWOA-LSSVR are used as the process parameters for blade processing. When the dimensional error of the processed area of the blade enters the design tolerance zone of ±0.05 mm, it is considered qualified. The qualified rate of the sampling points in the two processing experiments reaches 93.59%, which plays a certain guiding role in the actual processing of the blade. Conclusions A prediction model for process parameters is established by using the least squares support vector machine suitable for small sample sizes. To improve the algorithm accuracy of model establishment and avoid falling into local optima, the enhanced whale algorithm is adopted to optimize the hyperparameters of the least squares support vector machine, and a prediction model with a determination coefficient of 96.031% and an average absolute error of 0.012 128 mm is established. By comparing with the prediction models optimized by WOA and PSO, the established prediction model has certain advantages in terms of determination coefficient, mean absolute error and mean square error. The reproduction experiment of the removal amount is carried out. After two processing experiments, a processing result with a qualified rate of 93.59% at the sampling points is achieved, proving the feasibility of using this method to achieve fixed-point and quantitative removal of the blade surface material.

Vibration suppression method for robot abrasive belt polishing of narrow space parts

LI Weigang, WEI Jinhui, WANG Yang, ZHAO Jibin, LI Lun, ZHU Guang

2025, 45(4): 561-568. doi: 10.13394/j.cnki.jgszz.2024.0119

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Objectives With the rapid development of the aviation industry, the surface quality requirements for critical aero-engine components such as integrally bladed disks and integrally bladed rotors have increased. These components have narrow blade passages and poor accessibility, making traditional grinding tools prone to interference. Moreover, the weak stiffness of thin-walled parts and the grinding system can cause severe vibrations during robotic grinding, leading to surface defects and irreversible damage, thus limiting processing quality. This study proposes a vibration suppression method for thin-walled parts in confined spaces to reduce grinding vibrations and improve surface quality and stability. Methods A combined approach of theoretical modeling, tool optimization, and experimental validation is used. First, a dynamic model of robotic grinding for thin-walled parts is established, considering both flutter and forced vibrations, to identify key process parameters affecting vibration stability. A passive vibration control method is then applied by adding a spring damper to the traditional belt grinder to increase system damping and by downsizing the tool for better accessibility. Finally, orthogonal experiments are designed to optimize key process parameters and validate the vibration suppression effect of the optimized belt grinder. Results The dynamic model indicates that contact force, belt speed, feed rate, and system damping significantly affect vibration stability. Analysis of the forced vibration model shows that damping effectively reduces vibration amplitude near resonance frequencies. Experimental vibration signals shows that the optimized belt grinder reduces vibration amplitude by approximately 38.8% compared to the traditional one. Mean analysis of vibration experiments reveals that belt speed and belt joint stiffness negatively correlate with vibration stability, while contact force and feed rate show a decreasing-increasing trend. Range analysis indicates that belt speed and feed rate have the greatest impact on vibration stability, suggesting these parameters should be closely controlled during grinding. After grinding with the optimized belt grinder, the blade surface is smooth and free of vibration marks, with surface roughness R_a reduced to below 0.4 μm, meeting technical requirements. Conclusions Passive vibration control and parameter optimization are used to suppress vibrations during robotic grinding of thin-walled parts. The vibration-suppressing belt grinder, with increased damping and a downsized design, effectively reduces grinding vibrations, enabling interference-free grinding in confined spaces and achieving high surface quality. Orthogonal experiments shows that feed rate and belt speed significantly affect vibration stability. Reducing belt speed and feed rate and using softer belt joints can further suppress vibrations during grinding.

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2025 Vol. 45, No. 4

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Current Issue 2025 Vol. 45, No. 4

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Current Issue
2025 Vol. 45, No. 4