金刚石与磨料磨具工程

R&D course and technology development trend of CBN grinding tools in China

LIU Mingyao, LI Kehua, ZHAO Xinghao

2017, 37(1): 1-6. doi: 10.13394/j.cnki.jgszz.2017.1.0001

Abstract(348)

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Abstract:
R&D course and manufacturing technology of CBN grinding tools in China are reviewed in this paper.The characteristics are summarized based on bonding system, processing technology and abrasives specifications.Then the future development trend of CBN grinding tools is analyzed according to market structure and manufacturing technology, and further applications of the tools in important area, such as to machine bearings and to grind hard-to-machine material, are predicted.

Properties of boron doped diamond films prepared by new type of boron source

WANG Liang, JIANG Caiyi, GUO Shenghui, GAO Jiyun, HU Tu, YANG Li, PENG Jinhui, ZHANG Libo

2017, 37(1): 7-12. doi: 10.13394/j.cnki.jgszz.2017.1.0002

Abstract(438)

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Abstract:
Diamond films with different boron concentrations are prepared by using microwave plasma chemical vapor deposition with ethanol-boron-oxide solution as boron source.SEM, XRD, Raman spectroscopy and electrochemical work station were used to observe and study the surface morphology, crystal structure and electro-chemical properties of the film.Resultsshow that with the increase of boron concentration, crystalline size of diamond film first decreases and then increases, while the potential window decreases from 3.1 V to 2.6 V and the anodic current decreases from 0.022 7mA·cm^-2 to 0.011 9 mA·cm^-2.But such increase has almost no influence on background current and electro-chemical reversibility.

Manufacturing process of diamond wire saw by composite-brush-plating method

YAN Xiaotong, ZUO Dunwen, SUN Yuli, LI Rui, XU Yang

2017, 37(1): 13-18,24. doi: 10.13394/j.cnki.jgszz.2017.1.0003

Abstract(249)

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Abstract:
The effect of process parameters on the performance of wire saw was analyzed by self-made composite brush-plating manufacturing device, and the optimum process parameters were found out.Based on making clear the determination of the permissible current density, the effect of process parameters on the distribution density of abrasive grains was investigated by single factor experiment and orthogonal experiment.The experimental results showed that the permissible current density increased and then decreased with increasing felting speed, and the permissible current density reached the extreme value at 300 to 500r/min, when there was no abrasive particles in the plating solution.The main factors affecting the distribution density of abrasive grains were the wire speed, the current density, and the felt speed.The maximum parameters of abrasive distribution density were:wire speed 15mm/min, current density 19kA/m², felt speed 450r/min.

Numerical analysis on hydrodynamic pressure in grinding contact zone

MAO Shujie, XU Jiuhua, ZHAO Zhengcai, FU Yucan

2017, 37(1): 19-24. doi: 10.13394/j.cnki.jgszz.2017.1.0004

Abstract(403)

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Abstract:
In the grinding process, hydrodynamic pressure has great influence on flow rate, lubrication and cooling behavior of the coolant lubricate.Based on hydrodynamic lubrication theory, mathematical model of the hydrodynamic pressure in grinding contact zone is built.After simplifying the differential equation into Poisson equation, numerical solution of the hydrodynamic pressure is presented by finite difference method and optimized in efficiency by iterative model.Characteristics of grinding wheel are also considered into the mathematical model based on which the hydrodynamic pressure could be estimated according to the wheel texture, the gap between wheel and workpiece, and the cutting speed.The experimental results correspond to the mathematical results and show that this mathematical model can be used for hydrodynamic pressure prediction and provide reference for the grinding process.

Trace rare gases OES: nonintrusive method for the process of CVD diamond film growth under different carbon source

FAN Yongzhi, WANG Chuanxin, YI Cheng, DAI Kai, XU Qingbo, MA Zhibin, WU Chao

2017, 37(1): 25-28,33. doi: 10.13394/j.cnki.jgszz.2017.1.0005

Abstract(278)

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Abstract:
The diamond films were prepared by hot filament chemical vapor deposition.Trace rare gases optical emission spectroscopy (OES) was used to measure the active species during the diamond growth.The quality and morphology of grown diamond films were characterized by SEM and Raman spectra.When the other parameters were kept constant, with the increasing gas flux of the carbon source, the electron temperature generally decreased.However, if the carbon source flow was between 50cm³/min and 70cm³/min there appeared an abnormal situation, which was to first increase and then decline, maximum peak at the vicinity of 60cm³/min, when the charged particles reached the substrate with the maximum flux and energy.Meanwhile, the content of carbon-containing groups, such as CO, C₂ and CH, was at there minimum value near vicinity of 60cm³/min minimum.Vapor depositing process went towards the direction to grow diamond film, with maximum growth rate.However, the quality of diamond films decreased as the concentration of carbon source increased.

Investigation on deposition and patterning of low residual stress HFCVD boron-doped diamond film

ZHAO Tianqi, WANG Xinchang, SUN Fanghong

2017, 37(1): 29-33. doi: 10.13394/j.cnki.jgszz.2017.1.0006

Abstract(319)

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Abstract:
Raman spectroscopy was applied to analyze the residual stress of boron-doped diamond film on silicon wafer by different growth pressures and different carbon source concentrations.Photolithography and etching technique were used to fabricate diamond micro-structures.Resultsshow that the residual stress in the diamond films generally tends to be compressive stress.It is also found that the residual stress in the diamond film could significantly be reduced by optimizing the growth pressure and that it changes from compressive stress to tensile stress while the growth pressure is increased from 1.3kPa to 6.5kPa.The carbon source concentration has small effect on residual stress but big influence on the diamond film quality.In the end, cantilever, angle accelerometer, acoustic diaphragm were fabricated from the low residual diamond film by photolithography and etching.

Review on dental ceramics grinding

ZHAO Danna, WANG Chengyong, ZHOU Shaobo, JIANG Wentao, MAO Xueli, ZHENG Lijuan

2017, 37(1): 34-42. doi: 10.13394/j.cnki.jgszz.2017.1.0007

Abstract(448)

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Dental ceramic restorative materials take a dominant place due to the advantages such as excellent biocompatibility, unique aesthetic and stable chemical properties.However, complex surface characteristics and hard-brittle properties of dental ceramic restorative materials caused difficulties in the computer aided design/computer aided making (CAD/CAM) processing and subsequent grinding, such as complicated craft, high failure rate and surface damage of dental ceramics.Thus, it is of great importance for reducing material damage to fully understand the special grinding tools and their performance and to optimize the parameters.Methods and tools of denture processing are introduced, as well as the removal mechanism, grinding force and grinding surface quality of dental ceramic restorative materials.In the end, main directions for further developing are put forward.

Fabricating Ti₃SiC₂-diamond composites by spark plasma sintering induced self-propagation reaction

ZHANG Wangxi, XIA Tao, LUO Wei, LIANG Baoyan

2017, 37(1): 43-46. doi: 10.13394/j.cnki.jgszz.2017.1.0008

Abstract(348)

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Ti₃SiC₂-diamond composites were fabricated by spark plasma sintering induced selfpropagation reaction with 3Ti/Si/2C powders as bonder.The effect of holding time on the phase composition and microstructure of composites were studied.The result shows that Ti₃SiC₂ phase is formed when heated at 1170℃, whose main phases are Ti₃SiC₂, Ti₅Si₃ and TiC.It is also found that Ti₃SiC₂ content in the sample obtained at 1500℃is higher with fully reacted raw materials.The main phase of the sample containing 10wt% diamond is Ti₃SiC₂ and TiC.Additionally, small amounts of Si, SiC and diamond are also obtained.Ti₃SiC₂ content in the sample with holding time of 1min is higher, whose grains is lathe-structured and bonds well with diamond.Ti₃SiC₂ content in the sample with holding time of 5 min is lower, mainly composed of many TiC particles.In addition, the diamond is seriously graphitized, forming thick transition layer.

Tensile test and section analysis on matrix of brazing diamond bit

WANG Cong, BU Zhanggen

2017, 37(1): 47-50,55. doi: 10.13394/j.cnki.jgszz.2017.1.0009

Abstract(276)

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Mechanical property is a key performance for matrix of drilling bits, which used to be hard to test.Therefore, a new model is designed for sintering specimen.Then the specimen is used to test tensile strength and analyze fracture morphology.Resultsshow that the matrix bonds well with bits and that there is carbonizing reaction between matrix and diamond surface.It is also found that adding diamonds will decrease the tensile strength of the matrix.In this experiment, adding diamond could decrease the tensile strength of matrix up to by 53.8%.

Dynamic friction dressing of the diamond abrasive brick by W-Mo-Cr alloy

WANG Chunhui, AN Runli, SHI Shuangji, GUO Dongming

2017, 37(1): 51-55. doi: 10.13394/j.cnki.jgszz.2017.1.0010

Abstract(308)

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In order to solve the problem of dressing course-diamond abrasives, dressing experiments on diamond abrasive bricks with abrasive size 297μm to 420μm were conducted with W-Mo-Cr alloy as dressing material.The abrasive height consistency and the micrographs of the abrasive were measured before and after dressing.Then grinding experiments on WC material were conducted separately.Resultsindicate that the dressing method has high dressing efficiency and the abrasive height consistency of the diamond wheel has been greatly improved by 60%.The surface quality of WC material is evidently improved after dressing and the surface roughness of WC material reaches R_a0.149μm.

Influence of wheel stiffness on grinding performance and product machining quality

ZHAO Yanjun, QIAN Guanwen, LIU Quanwei, ZHANG Gaoliang, WANG Lihua, SHAO Junyong

2017, 37(1): 56-60. doi: 10.13394/j.cnki.jgszz.2017.1.0011

Abstract(309)

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By comparing machine power, grinding temperature, tool surface roughness and the quality of the cutting tool edge, the influence of grinding wheel stiffness on grinding performance and quality of cutting tools was analyzed.It has been proved that, in a certain extent, the reduction of grinding wheel rigidity could improve grinding performance and quality of the tool.In addition, the rigidity improvement of grinding wheel is obvious when adding 10vol% nylon, the average grinding temperature of which is 50℃lower than that of common grinding wheel under the same grinding conditions.After grinding the same number of workpieces, the machining power of low rigidity grinding wheel is 30% to 50%that of the ordinary wheel.It is found that tool surface roughness value Racan reach lower than 0.02μm after grinding with uniform ground surface.At a microscope of 500 times, no collapse edge defect can be seen, which means that the blade qualityis improved significantly.

Research on cutting silicon nitride ceramic hole with PCD tools

BAI Hepeng, DONG Hai, YANG Haijun, FANG Yu

2017, 37(1): 61-65,73. doi: 10.13394/j.cnki.jgszz.2017.1.0012

Abstract(276)

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The inner hole of silicon nitride ceramic are turned with PCD tools.Firstly, the removal mechanisms of silicon nitride ceramic is studied, which mainly includes the brittle removal and the ductile removal, and the brittle removal is the main removal mechanism.Secondly, the influences of rake angle, cutting speed, cutting depth and feed rate on the cutting force are studied.Resultsshow that the influence of rake angle on cutting force is not obvious, and that the cutting force increases with the increase of cutting speed, cutting depth and feed rate.The radial force is greater than the feed force and the main cutting force.Finally, the influences of the parameters on the surface roughness are mainly studied.The results show that the most significant impact factor on surface roughness is feed rate, followed by cutting speed and cutting depth.The rake angle has little impact.When they are 0.08mm/r, 32.97m/min, 0.10 mm and-5°, respectively, there is a better comprehensive balance between surface roughness and tool life.

Grinding force of two-dimensional ultrasonic-ELID composite grinding system

MA Xinyi

2017, 37(1): 66-69,73. doi: 10.13394/j.cnki.jgszz.2017.1.0013

Abstract(314)

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Based on theoretical research on grinding force of hard-brittle material in two-dimensional ultrasonic-electrolytic in-process dressing (ELID) composite grinding, the grinding force model of ultrasonic-ELID composite grinding is established.According to the grinding force formula, it is found that grinding force is associated with amplitude and angular frequency of ultrasonic wave.At the same time, grinding force also increases with the decrease of current.Actual grinding force at different grinding depth and wheel speed are compared with those theoretical ones.Resultsshow that both actual and theoretical forces are similar.It is also found that normal and tangential grinding forces increase with the increase of grinding depth or the decrease of wheel speed.

Study on color change of synthetic type Ib diamond crystals treated by high temperature and high pressure annealing

YUAN Hengxin, ZANG Chuanyi, LIU Bo, CHEN Xiaozhou, CHEN Kui, LI Ming

2017, 37(1): 70-73. doi: 10.13394/j.cnki.jgszz.2017.1.0014

Abstract(340)

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Type Ib diamond crystals, synthesized by using temperature gradient method, were treated by high temperature and high pressure annealing through domestic cubic press, then the samples were tested by colorimeter, and Fourier transform infrared spectrometer.It was found that under the condition of high temperature and high pressure, accompanying by the aggregation of nitrogen atoms, the initial type Ib diamond crystal had experienced a process of color change, which became darker at first, and then faded gradually, until it turned to a colorless type Ia diamond single crystal.

Optimization design and application of PDC bit in horizontal well

XU Jianfei, LIANG Xuejin, ZHAO Xiaobo

2017, 37(1): 74-77. doi: 10.13394/j.cnki.jgszz.2017.1.0015

Abstract(345)

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Compared with conventional polycrystalline diamond compact (PDC) bits for vertical and directional drilling, the gauge is more easy to wear for horizontal PDC bit, which suffers more much impact load and requires better steer ability.According to the horizontal strata characteristics of Honghe oilfield in Ordos basin, the cutter size and back rake angle are optimized through indoor experiment.Based on the characteristics of horizontal well bit, the bit profile is designed to be of shallow inner cone, short external cone and big crown arc.The gauge is enhanced with "active gauge cutter and low friction gauge pad" and the hydraulic structure is enhanced with asymmetric and multinozzle arrangement.The field application shows that the footage of new drill bit is comparing to ordinary bit, the footage is increased by 193%comparing with that of ordinary bit, and the penetration rate is increased by 132%.

Effect of different disc materials on sapphire wafer lapping process

SHI Linfeng, HAN Xue, GAO Yongjuan, LI Kehua, SU Hongliang, ZHAO Xiuxiang, LIU Quanwei

2017, 37(1): 78-80. doi: 10.13394/j.cnki.jgszz.2017.1.0016

Abstract(262)

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Influence of disc material and abrasive on lapping effect of sapphire wafer is analyzed based on actual machining.Lapping effect,product yield and lapping efficiency are compared when using cast iron disc(CID),ceramic compound disc(CCD),resin-copper disc(RCD)and polyurethane cloth(PUC)with B₄C or diamond slurry.The results show that surface quality of sapphire wafer lapped by PUC is best,R_a0.058μm,and that the lapping efficiency of CCD is highest,0.305μm/min with product yield at 96.08%.In conclusion,PUC and diamond slurry are recommended when requiring higher surface quality,such as R_a ≤ 0.06μm,while CCD with B₄C slurry is better if more emphasis is put on cost and efficiency(R_a ≤ 0.08μm).

Research and development of polycrystalline diamond cutter used on road milling machine

LU Canhua, ZHANG Tao, LIU Juntao, DOU Ming, NING Junlei

2017, 37(1): 81-84. doi: 10.13394/j.cnki.jgszz.2017.1.0017

Abstract(260)

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Polycrystalline diamond cutter, which is used on road milling machine, is prepared by using connecting technology of nano-bond gradient transition layer on cubic press.Its wear resistance, impact resistance and thermal resistance are tested by using wheel-dress and hammer-drop.Resultsshow that the wear ratio of prepared cutter is more than 250 000, and that its impact toughness is 1220 J.It is also found that the cutter performs good thermal stability at 750℃for 1.5h.When milling asphalt concrete pavement, service life of this cutter is 6times as long as that of carbide alloy cutter.

2017 Vol. 37, No. 1

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