金刚石与磨料磨具工程

Preparing SiO₂/ZnO/diamond/silicon multilayer structure for surface acoustic wave devices

CHEN Liangxian, LIU Jinlong, YAN Xiongbo, SHAO Mingyang, AN Kang, WEI Junjun, LI Chengming

2019, 39(2): 1-7. doi: 10.13394/j.cnki.jgszz.2019.2.0001

Abstract(242)

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Abstract:
To prepare the multilayer structure for surface acoustic wave devices, the deposition parameters of ZnO and SiO₂films were optimized using magnetron sputtering method and SiO₂/ZnO/ diamond/Si multilayer structure was prepared. With the increase of the argon oxygen ratio, the deposition rate of ZnO thin films were accelerated, and the surface roughness became larger. The atomic molar fraction ratio of ZnO films approached ideal 1∶1. All ZnO films prepared under different argon oxygen ratios presented (002) preferred orientation. At the argon oxygen ratio of 7∶1, ZnO film possessed the fine columnar grains and higher C-axis preferred orientation. The SiO₂/ZnO/diamond/Si multilayer structure with clear interface was obtained on diamond/Si substrate by using the optimal deposition process of ZnO and SiO₂thin films.

Surface roughness control technology of rake face of natural diamond tool

JIA Lu, ZHANG Xiaofeng, XIA Zhihui, WANG Wensheng, LEI Dajiang

2019, 39(2): 8-12. doi: 10.13394/j.cnki.jgszz.2019.2.0002

Abstract(348)

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The development and technical characteristics of diamond tools are introduced. A grinding method for controlling the surface roughness of the rake face of natural diamond tools is designed. The results show that for the diamond (100) surface, the surface roughness is good along "hard" direction with more grinding heat while poor in the "soft" direction with less grinding heat. By optimizing the grinding angle, the surface roughness of the rake face of the diamond tool can reach a goodR_avalue of 0.3 nm. Good application effects are presented in the ultra-precision cutting.

Sawed surface analysis of natural diamond

SHI Guangfeng, FU Wang, WANG Shukun, HAN Dongdong, ZHANG Hua, LIU Siyu

2019, 39(2): 13-16. doi: 10.13394/j.cnki.jgszz.2019.2.0003

Abstract(262)

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Sawing diamond is a cutting method with high processing precision. Diamond cutting machine is used to cut natural diamond, and then the sawing diamond cutting surface is detected and analyzed by optical microscope, roughness measuring instrument and X-ray diffractometer. The surface morphology, roughness and crystal image of natural diamond (100) crystal surface are obtained. The results show that tool trace is the main factor affecting the quality of natural diamond sawing surface processing. It is also found that isomerization of carbon occurs on the surface after cutting and generates a non-graphitizing carbon allotrope, whose content on the surface of the tool trace is 8.3% but 2.0% on smooth surface. Good natural diamond cutting surface can be obtained by normal sawing method.

Application of back propagation neural network technology on diamond test

LI Shichao, WANG Zhongxiao, QI Yanjie

2019, 39(2): 17-20. doi: 10.13394/j.cnki.jgszz.2019.2.0004

Abstract(276)

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The ellipticity, transmittance and magnetic susceptibility of diamond are taken as input and the impact toughness (TI) and thermal impact toughness (TTI) as output to establish the mapping relationship between the inputs and outputs by BP neural network. Then a BP neural network prediction on TI and TTI values of diamonds are obtained. The results show that the prediction of TI and TTI values are relative accurate. The average relative error rate between the predicted values and the detected ones is not higher than 1.4%, and the maximum relative error rate is not higher than 5.4%. Therefore, the BP neural network prediction could replace the current damage detection methods to some extent.

Precision of rake face of mechanically lapped single crystal diamond tool

WU Bairong, XUE Changxi

2019, 39(2): 21-25. doi: 10.13394/j.cnki.jgszz.2019.2.0005

Abstract(274)

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In order to improve the precision of diamond tool, the model of mechanical lapping diamond rake surface is analyzed, and experiments are implemented to study the influence of scaife pre-lapping quality and lapping crystal direction on the rake surface precision of diamond tool. After fully pre-lapping the scaife, the roughnessR_aof the diamond tool rake surface decreases from 1.308 nm to 0.920 nm. In the fine lapping of (110) crystal surface, the surface roughness of <100> crystal orientation after lapping is 0.540 nm and the surface roughness along <110> crystal orientation is 0.430 nm, realizing the precision lapping of diamond tools.

Factors influencing quality of electroless plating nickel on diamond powder

FANG Lili, CHENG Bingliang, WU Xiaolei, GUO Ranran, LI Yizhe, WANG Benhai

2019, 39(2): 26-31. doi: 10.13394/j.cnki.jgszz.2019.2.0006

Abstract(411)

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A layer of nickel is coated on the surface of diamond powder by electroless plating. The effects of the plating bath composition and plating conditions on the results of electroless plating of diamond powder are investigated by orthogonal experiments and SEM. The results show that the influence order of complexant on weight gain is as follows: citric acid > ammonia > sodium citrate, and that the weight gain will be reduced without adding sodium citrate. The weight gain rate of electroless plating is related to the nickel grain size deposited on the surface of diamond powder, and the coated diamond powder with less leakage and less continuous crystals can be obtained when pH value is about 4. Nickel slag will be formed when not adding stabilizer, and excessive addition of stabilizer will inhibit the reaction. The reaction will proceed normally if the amount of dispersant is increased at excessive stabilizer. With the increase of diamond addition, the weight gain rate decreases and the best coating would be achieved at diamond addition of 6 g. With the increase of temperature, the rate of weight gain increases and 80~85 ℃ is the optimum range.

Fabrication of submicron α-Al₂ O₃ by the transformation of microcrystalline γ-Al₂ O₃ under high-pressure

TONG Feifei, WANG Haikuo, DONG Bingshun, HOU Zhiqiang, YANG Yanan, SHEN Yunpeng

2019, 39(2): 32-36. doi: 10.13394/j.cnki.jgszz.2019.2.0007

Abstract(257)

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Microcrystalline γ-Al₂O₃is used as raw material to prepare α-Al₂O₃from γ-Al₂O₃using the hinge-type cubic press under the pressure of 5 GPa with different temperatures. The results of X-ray diffraction analysis show that the obtained powders and bulk materials are pure α-Al₂O₃phase. The scanning electron microscope analysis shows that the minimum grain size of the α-Al₂O₃is about 80 nm and the average grain size of the α-Al₂O₃synthesized under the pressure of 5 GPa and the temperature of 800 ℃ is 340 nm. Experimental results show that the submicron α-Al₂O₃is fabricated by high pressure phase transformation of microncrystalline γ-Al₂O₃. Compared with the normal pressure sintering method, the complete phase transformation from γ-Al₂O₃to α-Al₂O₃can be achieved at 600 ℃ by high pressure sintering, which obviously reduces the synthesis temperature of α-Al₂O₃materials.

Research progress of metal bond diamond tools

WU Yanping, YAN Qingzhi

2019, 39(2): 37-45. doi: 10.13394/j.cnki.jgszz.2019.2.0008

Abstract(939)

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Diamond tools are widely used in the grinding and cutting of natural stone, ceramics, glass, concrete, hard alloys, etc. Metal bond diamond tools have become the main force of diamond tools due to their good mechanical and thermal properties. With the continuous emergence and ever-changing of new ceramic concrete and other processing objects, diamond tools are required to be continuously modified to improve cutting efficiency, slow down wear, and reduce manufacturing and use costs. This paper reviews the properties of synthetic diamond particles, the composition and basic properties of different types of metal binders, the interface state of diamond and metal matrix, and the measures to improve the bonding strength. The further prospects for the development of metal bond diamond tools are put forward.

Research progress of binders for polycrystalline cubic boron nitride (PCBN) and preparation technology

LI Liang, CHEN Yuqi, ZHOU Aiguo

2019, 39(2): 46-50. doi: 10.13394/j.cnki.jgszz.2019.2.009

Abstract(255)

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Polycrystalline cubic boron nitride (PCBN) is widely used in cutting hardened steel, gray cast iron, titanium alloy and superalloy because of its high hardness and other good properties such as wear resistance, thermal conductivity, high temperature stability and chemical stability. In this paper, the research and application of binders for PCBN are summarized. The bonding mechanism, advantages and disadvantages of three types of binders, namely metal/ceramic single-phase binder, metal-ceramic composite binder and new Ti₃SiC₂binder with its analogues, are introduced respectively. The preparation process and unique properties of Ti₃SiC₂binder and its analogues are emphatically introduced, the problems in whose preparation are also discussed.

Process and cutting performance of diamond tool with high Fe-content bond

HUANG Xia, ZOU Xinguang, LIU Wei, YANG Zhiwei, LIU Yibo

2019, 39(2): 51-54. doi: 10.13394/j.cnki.jgszz.2019.2.0010

Abstract(288)

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High Fe-content bond are designed and mechanical tests and fracture texture observation are done to their sintered segment for the purpose of evaluating their rationality of the component design and sintering process. Results show that the designed high Fe-content bond with component of (Fe)75(CuSn10)15(Cu-Ni)10 has a proper sintering temperature range of 910 to 940 ℃, hardness over HRB 90 and bending strength over 1200 MPa. Dimple tissue structure are apparently observed on the fractures which indicates that the bond has been well alloyed. At the same time, the wide process range means that it is adaptable for commercial fabrication. A low cost laser welding universal diamond saw blade LW350 is fabricated with this bond and comparisons are made to representative same kind of diamond saws on market by cutting tests taken on steel reinforced C45 concrete. The results show that self-fabricated diamond saw has lower sharpness at a level of about 15% decrease and longer life of about 20% exceeding while the cost is cut down apparently.

Uniform wear of solid abrasives in uncertain eccentricity plane lapping

ZHANG Di, SHANG Chunmin

2019, 39(2): 55-60. doi: 10.13394/j.cnki.jgszz.2019.2.0011

Abstract(207)

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The uniform wear of abrasives in the solid abrasives uncertain eccentricity plane lapping machining is the precondition to ensure the machining surface shape accuracy of the workpiece. According to the theory of uniform wear of abrasives in the solid abrasives plane lapping, the condition of uniform wear of the abrasives is discussed based on mechanical and kinematics analysis, and the trajectory equation and relative velocity of the abrasives relative to the workpiece are obtained, as well as the pressure distribution between the abrasives and the workpiece. The effects of structure parameters, swing parameters and speed ratio on wear of abrasives are analyzed. The results show that the optimum structure of abrasives are Δr=20 mm,α=45°, ε=3 mm, that the optimum swing parameters areφ=6°,T=1 s,e₀=60 mm and that the optimum speed ratiok_ωis 2.

Structure optimization of electroplating CBN grinding wheel

LIU Jiangxian, QU Xiaobo, ZHANG Xiaopan

2019, 39(2): 61-63. doi: 10.13394/j.cnki.jgszz.2019.2.0012

Abstract(267)

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End face burn occurred when grinding CBN grinding wheel in grinding crankshaft journal and end face. In condition that adjusting the cooling system does not solve this problem, the structure of grinding wheel is redesigned by modifying the end surface and grain type. The newly designed and prepared electroplated CBN grinding wheel is tested on grinding experiment. Results show that at the same cooling system, the new electroplated CBN grinding wheel could solve the problem of burns in the mentioned process.

New technology to magnetorheological finishing aspheric cylindrical mirror

LUO Bin, YAN Qiusheng

2019, 39(2): 64-71. doi: 10.13394/j.cnki.jgszz.2019.2.0013

Abstract(246)

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Cylindrical mirror is a high-precision optical element, which requires not only very low surface roughness, no surface/subsurface damage and low residual stress, but also parallelism and verticality of cylindrical generatrix. By analyzing the influence of traditional grinding and polishing technology and computer controlled optical surfacing (CCOS) on surface roughness, surface profile accuracy and generatrix error of cylindrical mirror after machining, the advantages and disadvantages of two methods are summarized. Aiming at the low efficiency, high roughness and surface/subsurface damages of the existing machining methods,a new magnetorheological finishing process with symmetrical structure for aspheric cylindrical mirror is proposed, and the feasibility of the new process is verified by the experiment of time parameters. The surface roughness and profile accuracy of the cylindrical mirror are effectively reduced. At the polishing time of 40 min, the surface roughnessR_adecreases from 1.84 to 0.36 μm, the local profile accuracyRMS₁decreases from 1.91 to 0.24 μm, and the generatrix section profile accuracyRMS₂decreases from 4.1 to 0.68 μm.

Power prediction model of circular saw blade sawing granite based on multivariate nonlinear regression analysis

WANG Zhongxiao, LI Shichao, QI Yanjie, GUO Wenhui, YANG Gaofeng, ZHANG Yuhong

2019, 39(2): 72-75. doi: 10.13394/j.cnki.jgszz.2019.2.0014

Abstract(259)

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Based on the experimental data of cutting granite with φ350 mm diamond circular saw blade, the prediction model of cutting power under the condition of cutting granite with diamond circular saw blade was established by means of multivariate non-linear regression analysis. The feasibility of the prediction model was verified by comparing the experimental data with the predicted data. The results show that the fitting effect of the model predicted by the multivariate non-linear regression analysis method is better. Compared with the experimental power, the average absolute relative error of the predicted power is only 2.17%. The main factor affecting the sawing power of circular saw blade is feed speed, followed by the comprehensive strength of diamond abrasive, and finally the sawing depth.

Analysis on cooling and lubrication mechanism of high-pressure cutting fluid for vermicular cast iron cutting based on AdvantEdge

XIAO Xiaodong, SU Guosheng, FENG Limin, YI Mingdong

2019, 39(2): 76-82. doi: 10.13394/j.cnki.jgszz.2019.2.0015

Abstract(302)

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Based on the cutting fluid simulation function of AdvantEdge, 2D turning simulation is carried out for vermicular cast iron under different cutting fluid pressures. The variation of chip deformation, cutting temperature, tool-chip friction and cutting force in the cutting process ae studied. The cooling and lubrication mechanism of high-pressure cutting fluid are also analyzed. The simulation results show that the increase of cutting fluid pressure can reduce the lengths of the sticking zone and the sliding friction zone, thereby increasing the heat exchange rate between workpiece and fluid. At the same time, the high-pressure cutting fluid can overcome the gas protective layer formed by the Leidenfrost effect, achieving better heat convection and cooling. However, the increased pressure does not lead to better cooling effect and the cutting fluid pressure should be 15 to 18 MPa for good cooling and lubrication at low energy cost.

Finite element simulation of ultrasonic vibration turning titanium alloy

PANG Yu, MA Yuan, XU Chao, FENG Pingfa

2019, 39(2): 83-88. doi: 10.13394/j.cnki.jgszz.2019.2.0016

Abstract(310)

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As a lightweight and high-quality structural material, titanium alloy is widely used in aerospace and other fields. Meanwhile, titanium alloy is also a difficult-to-process material, so it is difficult to achieve high quality and highly efficient processing of titanium alloy by conventional machining (CM). Ultrasonic vibration machining (UVM) converts ultrasonic signals into mechanical vibrations to achieve periodic separation of workpieces and tools for better machining effects. Therefore, titanium alloy (TC4) is taken as the research object to establish Abaqus two-dimensional turning finite element model and carry out simulation comparison of CM and UVM for TC4. The simulation results show that UAM can effectively reduce the average the cutting force and the cutting temperature at tool tips compared with CM. Moreover, the cutting effects are further improved with increasement of vibration amplitude under set conditions.

Prediction of processing effect of wire electrode discharge grinding of insulation engineering ceramic with particle swarm optimization fuzzy neural network

WANG He, YANG Yong

2019, 39(2): 89-94. doi: 10.13394/j.cnki.jgszz.2019.2.0017

Abstract(205)

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In the process of wire electrode discharge grinding (WEDG) of insulating engineering ceramic, there is a close relationship between the technical indexes and process parameters. The operators can only set the process parameters according to their past experience during the practice, and predict the processing results to a certain extent. If the setting of process parameters is unreasonable, it will greatly affect the processing efficiency, accuracy and capacity of machine tools. Therefore, based on BP fuzzy neural network(BPFNN), a prediction model is presented for the effect of technical indicators for WEDG of insulating engineering ceramic. Rough set theory is used to reduce the attributes and rules of training samples and improved particle swarm optimization (PSO) is used to optimize the network. The models before and after optimization are used to simulate the processing of boron carbide (B₄C) ceramics and the results are compared. It is found that the optimized model has the advantages of fast prediction speed, small error and high precision.

Research progress of WC-based cemented carbide tool materials

XIONG Jianchao, ZOU Qin, LI Yanguo, WANG Mingzhi, HE Wenquan

2019, 39(2): 95-102. doi: 10.13394/j.cnki.jgszz.2019.2.0018

Abstract(416)

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WC-based cemented carbide is one of the main cutting tool materials used in industrial production. Based on a brief overview of WC-based cemented carbide tools, the types and development status of WC-based cemented carbide tool materials are introduced, and the research progress of WC-based cemented carbide tool materials is discussed. It is hoped to provide some references for the development and preparation of new WC-based cemented carbide tool materials.

2019 Vol. 39, No. 2

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