金刚石与磨料磨具工程

Analysis on economic operation of superhard materials industry in 2017

LI Zhihong, SUN Zhaoda, LI Lijuan

2019, 39(1): 1-8. doi: 10.13394/j.cnki.jgszz.2019.1.0001

Abstract(287)

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Based on 4 statistical tables and 28 analysis charts, this paper analyzes the growth of major economic indicators of the country and industry in 2017, and points out that the industry has come out of the trough in 2017. But sawing and drilling tools developed not so good due to the downturn in real estate. In this paper, it is analyzed in detail that import/export data of China′s customs statistics, and also the import data of the major developed economies of the United States, the European Union and Japan. The data show that China′s superhard materials products have a dominant position in the world, but there is a big gap between China′s precision tools like grinding wheel and cutting tools and developed countries′ products, such products have broad space for development.

Application of new superfine multi-component iron-basedcatalyst powder in self-sharpening diamond synthesis

TAN Suling, SUN Shuangshuang, QIAO Cuiya, SUN Jiping, LI Pengxu

2019, 39(1): 9-17. doi: 10.13394/j.cnki.jgszz.2019.1.0002

Abstract(337)

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A superfine multi-component iron-based catalyst powder with less oxide impurities was prepared by water-gas combined atomization technique. By controlling the type and content of the oxide impurities in the catalyst, the stability of the metallic film at diamond growth interface could be well controlled, improving the quality and self-sharpness of diamond. Furthermore, two-dimensional layered growth of diamond was improved under the stable thermodynamic and kinetic conditions by adjusting the synthesis process, improving the self-sharpening ability of step-like micro-fragmentation of diamond. The synthetic quality and crystal growth characteristics of diamond produced by conventional FeNi30 and newly designed catalyst were analyzed and compared by means of optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscope (EDS). The results show that the self-sharpness of the diamond produced by new catalyst is well improved, the sharpness of the cement diamond saw blade and wire saw prepared by the as-produced diamond is more than 15% higher than before, and the continuous working stability of the tools is remarkably improved.

Progress of research on nano-diamond dispersion

MIAO Weipeng, DING Yulong, ZHAI Lipeng, BAO Hua

2019, 39(1): 18-22. doi: 10.13394/j.cnki.jgszz.2019.1.0003

Abstract(476)

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Nano-diamond, which not only possesses the ultrahard characters of diamond but also the small size effect of nano-materials, is an important nano-powder material and has wide development space. However, its agglomeration limits the wide application of nano-diamond. To solve this problem, the industry has conducted a lot of research through physical dispersing methods and chemical treatments to disperse the diamonds. Hereby, the progress of research on the dispersion of detonation-synthesized nano-diamond in recent years are summarized, and the main mentality is concluded to provide reference for further development of dispersing nano-diamond.

Electroless plating of spherical Ni-Co-P alloy on synthetic diamond surface

CHEN Yiyan, ZHI Hongmei, LI Ming

2019, 39(1): 23-26. doi: 10.13394/j.cnki.jgszz.2019.1.0004

Abstract(385)

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To enhance the bonding strength between diamond and matrix, Ni-Co-P alloy is deposited onto the diamond surface by using electroless plating. The influence of different depositing parameters on the performance of the coated layer is studied by scanning electron microscope and X-ray diffraction. Results show that the best formula is cobalt chloride 11.8 g/L, nickel sulfate 8.7 g/L, sodium hypophosphite 18 g/L, sodium citrate 50 g/L, ammonium sulfate 60 g/L and addition agent 0.1 g/L and that the best parameters are solvent temperature 76 ℃, pH value 9.0 and coating for 2 h. At such formula and parameters the spherical protrusions are formed and strongly bonded to the diamonds. It is also found that if the coatings are heated at 400 ℃ or higher, there will precipitate stable phases such as Ni, Ni₃P, CoP and Co₂P.

Influence of different wetting agents on the propertiesof vitrified CBN grinding wheel mixture

LI Henan, WANG Zhiqi, LIU Bin, SUN Penghui, WANG Chaofu, XI Yaohui

2019, 39(1): 27-30. doi: 10.13394/j.cnki.jgszz.2019.1.0005

Abstract(440)

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The formability of vitrified CBN grinding wheel mixture is directly affected by wetting agent, which further affects the microstructure uniformity of grinding wheel. In this study, four new wetting agents, PVB ethanol solution, PAM water solution, PEG-6000 water solution and ISOBAM-110 water solution, were selected to compare with dextrin solution. The effects of these wetting agents on mixture uniformity, loose density, strength and microstructure of vitrified CBN grinding wheel mixture were studied. The results show that the mixtures with ISOBAM-110 and PAM are uniform, whose loose density are increased by 46.59% and 51.14% respectively with the strength of the segment increased by 17.71% and 35.08% and the inhomogeneity of grinding wheel decreased by 23.75% and 8.75%. The properties of the mixtures are improved obviously compared with dextrin solution.

Study on property of chromium-ceramic composite bondand its preparing methods by mechanical alloying

YU Nuoting, GUO Linshuo, BAO Feixiang, LIU Chunyang, ZHAO Yucheng, JIANG Weishi, HAN Jincan, WANG Mingzhi, ZOU Qin

2019, 39(1): 31-35. doi: 10.13394/j.cnki.jgszz.2019.1.0006

Abstract(377)

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Chromium powder and ceramic powder are used as initial material to prepare Cr-ceramic binder at different ratios by using mechanical alloying (MA). The mixture are treated with the following parameters: mass ratio of ball and powder 20∶1, rotation speed 350 r/min, balling time 12 h and some anhydrous ethanol as process control agent. Then the obtained composite powders are buried in SiC and sintered at 660 to 740 ℃. Mechanical tests are implemented to measure the flexural strength (by using three point bending method) and density and apparent porosity (by using Archimedes principle) of the specimens, and SEM and XRD are used to analyze the microstructure at fracture section and phase composition of the specimen. Results show that MA process could help to obtain uniformly distributed metal phase and ceramic phase in the composite bond. When the mass fraction of Cr powder is 30% and the mixture is sintered at 700 ℃ for 30 min, the flexural strength of the specimen reaches its maximum, which is 187 MPa. The chromium powders are well bonded to the ceramic powder through CrO on the surface of Cr particle, thus improving the overall flexural strength.

Effect of calcium fluoride on grinding performance of resin-bonded diamondgrinding wheel for silicon wafer

DING Yulong, HUI Zhen, XIONG Huajun, ZHAO Yanjun, BAO Hua

2019, 39(1): 36-40. doi: 10.13394/j.cnki.jgszz.2019.1.0007

Abstract(537)

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Solid lubricant Calcium fluoride (CaF₂) with different volume fractions is added into resin-bonded diamond wheels for single crystal silicon wafer grinding. Its influence on surface structure and wear ratio of the wheel, as well as the spindle current of grinding machine, is analyzed. The surface roughness of the wafer and the thickness of damage layer on its surface are measured and calculated. Results show that as the content of CaF₂ increases, the current, the wear ratio and the surface roughness and damage layer thickness all decrease. When the volume fraction of CaF₂ added is 25%, the current is about 6.4 A, and wear ratio of wheel decreased to 0.448 6 μm, with R_a 0.056 μm, R_y 0.382 μm and R_z 0.396 μm on the wafer surface and thickness of damage layer0.559 6μm. In conclusion, the performance of resin-bonded diamond wheels and the quality of machined single crystal silicon wafer could be enhanced by adding CaF₂ as solid lubricant, and the best volume fraction of CaF₂ is 25%.

Vibration-assisted fixed abrasive polishing CaF₂ crystal

HUANG Junyang, LI Jun, WANG Jianjie, ZHANG Yuchi, ZHU Yongwei, ZUO Dunwen

2019, 39(1): 41-46. doi: 10.13394/j.cnki.jgszz.2019.1.0008

Abstract(344)

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In order to improve polished surface quality of CaF₂ crystal and increase material removal rate, the method of vibration-assisted fixed abrasive polishing of CaF₂ crystal is proposed, which combined ultrasonic vibration with fixed abrasive polishing effectively. The effect of process parameters on material removal rate and surface quality are investigated by orthogonal experiment. The optimal parameters of CaF₂ crystal polishing is obtained with rotational speed 40 r/min, vibration frequency 40 kHz, slurry pH value 9, and rotation speed ratio 0.95. Under the optimal parameters, material removal rate is 324 nm/min, and surface roughness S_a is 1.92 nm in vibration-assisted fixed abrasive polishing CaF₂ crystal process. Compared with the results of fixed abrasive polishing without vibration, material removal rate is increased by 57% and surface roughness S_a is reduced by 35%. Vibration-assistance can increase material removal rate and enhance surface quality of the wafer by cavitation and intermittent contact in fixed abrasive polishing process.

Simulation of the dimpled surface generated by grinding outer circlewith abrasive phyllotactic arrangement wheel

CHE Dongze, LYU Yushan, CHEN Tianyu, XIONG Wei, LI Xingshan

2019, 39(1): 47-53. doi: 10.13394/j.cnki.jgszz.2019.1.0009

Abstract(391)

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Structured dimple surface can effectively reduce the drag friction resistance of the part surface, thereby improving the movement performance of the part in the fluid. A superhard material grinding wheel with phyllotactic-arranged abrasive grains is designed based on the theory of biological leaf alignment, and used to grind the structured dimple surface of outer circle. In order to explore the grinding principle of the structured dimple surface, the kinematics simulation of grinding process of abrasive grain phyllotactic arrangement wheel is carried out by using MATLAB. The influences of abrasive grain phyllotactic arrangement parameters and grinding parameters on the surface topography of structured pits in grinding area are studied. The simulation results show that the rotational speed ratio affects the dimple radial arrangement and dimple size, which is that the higher the rotational speed ratio is, the denser the dimple radial arrangement is and the smaller the dimple size is. The phyllotactic coefficient affects the dimple axial arrangement, thus smaller phyllotactic coefficient leading to denser dimple axial arrangement. The grinding depth affects the dimple size. As the wheel grinds deeper, the dimple width and depth become larger, and so does the burr heave height which is about half of the grinding depth.

Research on process of high-efficiency precise dicing optical glass

YIN Shaohui, CAO Junming, GONG Sheng, LIANG Zhenting, HU Tian, CHEN Fengjun, HUANG Shuai

2019, 39(1): 54-59. doi: 10.13394/j.cnki.jgszz.2019.1.0010

Abstract(412)

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Single factor tests are implemented on self-developed FAD 1210 high-precision and high-efficiency slicing machine. The influences of clamping method, dicing blade type and water flow rate on the sliced K9 optical glass are studied and evaluated by measuring the chipping size and the surface roughness of the glass. The results show that the fastening mode of glass substrate has the best effect on the cutting of K9 optical glass, followed by UV film and high temperature silicone tape. The effect of resin bond dicing blade is ideal when dicing glass, with smaller chipping size and better surface roughness. The metal dicing blade ranks next and the effect of electroplating dicing blade is worst. With the increase of dicing water flow rate, the chipping size and surface roughness decrease gradually. When the dicing water flow rate is more than 4.5 L/min, the dicing effect tends to be stable. When chipping K9 optical glass under the optimum parameters of glass substrate fastening mode, resin dicing blade and dicing water flow rate of 4.5 L/min, the dicing effect is the best with chipping size of 5.8 μm and surface roughness R_a of 10.5 nm.

Experimental research on plane lapping of fused silica glass substrate

YAN Qiusheng, LI Jisong, PAN Jisheng

2019, 39(1): 60-65. doi: 10.13394/j.cnki.jgszz.2019.1.0011

Abstract(491)

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The lapping of fused silica glass substrate is a basic process of its super smooth polishing. Free abrasive was used in rough grinding and fine finishing fused quartz glass on one side. The effects of abrasive mass fraction, rotation speed of grinding disc, flow rate of grinding fluid and grinding time on surface quality and material removal rate of fused quartz glass were studied. The results show that the material removal rate increases first and then decreases with the increase of abrasive mass fraction, grinding disc speed and grinding fluid flow rate. With the extension of processing time, the surface roughness R_a gradually reaches a stable level. The surface roughness R_a of fused quartz glass substrate reaches 0.11 μm at conditions of the mass fraction of abrasive particles 4%, the flow rate of abrasive fluid 20 mL/min, the speed of abrasive disc 60 r/min and the processing time 30 min. When fine finishing fused silica glass substrates, the surface roughness R_a of the substrates is the lowest after 50 minutes processing with 3 μm-sized CeO₂ particles, which is 4.11 nm.

Finite element analysis on heat distribution ratio during grinding CFRP

FAN Baopeng, CHEN Yan, CHEN Binbin, LIANG Yuhong, SUN Liang

2019, 39(1): 66-71. doi: 10.13394/j.cnki.jgszz.2019.1.0012

Abstract(404)

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Carbon fiber reinforced plastics possess high specific modulus, specific strength and specific stiffness, which shows great application prospects in the field of aeronautics and astronautics. When grinding carbon fiber reinforced resin composites composed of carbon fibers and resins, the grinding temperature may exceed the glass transition temperature of the resin, leading to resin burn-out and other defects. In order to study this problem, the semi-artificial thermocouple of carbon fiber composite and constantan wire is used to measure the in-situ temperature in grinding process, and the heat distribution between workpiece and others is studied by combining experiment with finite element simulation. It is found that the heat imported to workpiece is 2.0% to 3.5% of the total heat during grinding process.

Effect of resin hardness on cutting performance of resin diamond wire

GAO Wei, LI Jun, MA Bojiang, WANG Dongxue

2019, 39(1): 72-75. doi: 10.13394/j.cnki.jgszz.2019.1.0013

Abstract(372)

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The effects of different resin binders on the cutting performances of diamond wire were studied. Resin hardness samples were prepared with pure phenolic resin, epoxy modified phenolic resin and aryl modified phenolic resin respectively, and Shaw hardness of the samples was tested. Fracture surface of resin cured samples were observed by scanning electron microscopy. It was found that the densification of different resin cured sample was different. The resin diamond wires were made with these resins, and the monocrystalline silicon cutting experiment was carried out. The experimental results show that the diamond wire made of pure phenolic resin with high hardness and good compactness after curing has the smallest arch and shorter cutting time, and that the diamond particles are not easy to fall off thus possessing a strong cutting ability.

Experimental analysis on sawing performance ofsand-suspension-electroplated wire saw

ZHENG Chuxi, MA Xiaobin, XIE Qian, BI Wenbo, GE Peiqi, GONG Yang, LIU Tingquan

2019, 39(1): 76-79. doi: 10.13394/j.cnki.jgszz.2019.1.0014

Abstract(506)

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Suspended electroplated diamond wire saws with different sanding positions are used to machine single crystal silicon. The sawing performances of different wires are compared by recording machine time and calculating the efficiency. SEM is used to observe the sanding and wear conditions, and the surface roughness is measured by related instruments. Results show that the density of abrasive grain varies greatly as sanding position changes, while that is the highest when sanding position is close to the center of the launder. It is also found that the cutting efficiency is higher if the wire saw has higher abrasive density. The one with abrasive density of 585 per mm could cut 4.949 mm²/min, 138% higher than that of the compared saw which has abrasive density of 446 per mm and efficiency of 2.158 mm²/min. In addition, there is no big difference on surface quality of silicon wafer machined by wire saws with different abrasive density. The main wear or damage patterns of wire saw are abrasive wear, grain shedding and coating wear and damage.

Preparing diamond coating on cemented carbide powder by electrophoresis deposition

WAN Zhijian, HUANG Chuanzhen

2019, 39(1): 80-83. doi: 10.13394/j.cnki.jgszz.2019.1.0015

Abstract(296)

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The technology to deposit diamond coatings on cemented carbide powder by using electro-phoretic deposition method was investigated. The effect of the mass fractions of cemented carbide and MgCl₂·6H₂O on the quality of the coating was studied, and the prepared powders were characterized. When the masses of the cemented carbide powder, the diamond powder and MgCl₂·6H₂O were 28.0 g, 4.0 g and 1.0 g, respectively, the prepared diamond coating was uniform and good in density.

Particle size distribution of granite swarf by impregnated diamond bit

ZHAO Xiaojun, KANG Xin, PAN Feifei, PAN Bingsuo, DUAN Longchen

2019, 39(1): 84-88. doi: 10.13394/j.cnki.jgszz.2019.1.0016

Abstract(835)

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The granite swarf produced by impregnated diamond bits were collected during micro-drilling experiments. The particle size distributions of the swarf were analyzed to quantitatively investigate the particle size distribution laws and the effects of diamond parameters and drilling parameters on the swarf size distributions. The results show that the particle size distribution of the granite swarf is consistent with logarithmic normal distribution. Most swarf particle sizes vary from 40 to 100 μm. Meanwhile, the swarf particle size distribution is influenced by the diamond size, diamond concentration, bit pressure and rotate speed.

Influence of mesh type on the cutting simulationquality of aviation thin-walled cylinder

XU Jie, DENG Yi, ZHANG Jing

2019, 39(1): 89-94. doi: 10.13394/j.cnki.jgszz.2019.1.0017

Abstract(289)

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In order to explore the influence of element types and meshing methods on the turning simulation process of aviation thin-walled cylinder, Abaqus and AdvantEdge were used to compare and analyze the turning process of thin 3D model and thin-walled cylinder model, and the cutting simulation quality was evaluated with the main cutting force and chip morphology as the indexes. The results show that the hexahedral mesh can greatly save the computation time on the premise of guaranteeing the thin 3D cutting simulation accuracy. According to the comparison and analysis of the thin-wall cylinder model, the hexahedral mesh can better reflect the changes of physical parameters such as chip morphology and machined surface quality in the cutting process. Sweep method can improve the efficiency and surface quality of workpiece to a certain extent.

Simulation of high-speed scratching process of marble based onfinite element/discrete element coupling method

LIU Shuying, WANG Fuzeng, GUO Ziyu, YIN Fangchen

2019, 39(1): 95-100. doi: 10.13394/j.cnki.jgszz.2019.1.0018

Abstract(392)

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To study the grinding process of marble with abrasive particles, a high-speed scratch simulation model of single abrasive particle was established by means of finite element / discrete element method. By inserting the cohesive element with zero thickness into the solid element and controlling the failure of the cohesive element, the initiation and propagation of cracks in the marble machining process were realized. The effects of scratch depth and scratch speed on marble removal process were analyzed based on the established model. The results show that scratch force and thickness of the damaged layer increase with the increase of the scratch speed and depth, and that there is a positive correlation between the scratch force and the thickness of the damaged layer.

Preparation and characterization of high crystallinity hexagonal boron nitride

ZHANG Xiangfa, CHANG Qing, WEI Xing, SONG Mingzhi, LIU Qiankun, WANG Yongkai, WEI Chaoyang

2019, 39(1): 101-104. doi: 10.13394/j.cnki.jgszz.2019.1.0019

Abstract(485)

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Hexagonal boron nitride is prepared through heat treatment at 1 800 ℃ in a new high-temperature induction furnace, where boric acid and melamine are used as raw materials. The hexagonal boron nitride product is characterized by scanning electron microscopy, X-ray diffraction, laser particle size analysis and chemical analysis. The result show that the hexagonal boron nitride prepared by the process has high crystallinity, high purity and large crystal size.

2019 Vol. 39, No. 1

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