金刚石与磨料磨具工程

Study on boron and its co-doped diamond films

WANG Zhiwei, ZOU Qin, LI Yanguo, WANG Mingzhi

2019, 39(4): 1-8. doi: 10.13394/j.cnki.jgszz.2019.4.0001

Abstract(523)

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Abstract:
Adding impurity elements into diamond can obtain other properties on the basis of retaining its original excellent properties, for example, doping boron element can make diamond become P-type semiconductor. Co-doping other elements can improve the electrical properties and catalytic activity of diamond, and even change the conductive mechanism of boron-doped diamond films. In this paper, the preparation methods, structural characteristics and micro-morphology of boron and its co-doped diamond films are introduced in detail. The factors affecting the properties of boron and its co-doped diamond films and the modification methods are summarized.

Effect of ultra-high sintering pressure on performance of low content and fine particle PCBN

MU Longge, GAO Huiqiang, WANG Yongfeng, WANG Zhiqi, LI Henan, LEI Laigui, WU Wushan, XU Benchao

2019, 39(4): 9-13. doi: 10.13394/j.cnki.jgszz.2019.4.0002

Abstract(287)

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Sintering pressure is a key factor affecting the quality of PCBN. The pressure of industrial production is usually less than 6 GPa. In this test, through special design of press fittings, the assembly structure was optimized, and the high-precision temperature-controlled pressure-control system was used to study the sintering of low-content and fine-grained PCBN with the condition of more than 6 GPa. Through the volume wear ratio, CBN layer flatness and internal defect microstructure, the finished tool and E6 DCC500, Sumitomo Electric BNX20 turning test, to study the effect of ultra-high sintering pressure on low-content, fine-grained PCBN performance. The results show that the ultra-high sintering pressure can improve the wear resistance and flatness of PCBN and promote the diffusion sintering of CBN layer and cemented carbide layer.

Research on matrix material property of diamond tool with electrochemical preparation method

WANG Xingxing, LI Shuai, LONG Weimin, JIU Yongtao, ZHONG Sujuan, JIA Lianhui, DU Quanbin, SHANGGUAN Linjian, HUANG Yinghua

2019, 39(4): 14-21. doi: 10.13394/j.cnki.jgszz.2019.4.0003

Abstract(345)

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Diamond tools are widely used in stone, geology, ceramics, machinery, and electronics because of its superior processing capability. It is important to study the matrix properties for electroplating to improve the service life and processing efficiency of diamond tools. The research status on matrix materials of electroplated diamond tool were summarized based on material alloying, material compound and grain refinement in the past 20 years. Then the problems in the improvement of the properties on matrix material of electroplating diamond tool at present were proposed. Additionally, prospects and suggestions for the substrate metal of electroplating diamond tool in the future were presented.

Effects of CBN content on characteristics of PCBN composites in turning GCr15 hardened steels

GUO Jiahui, YAO Feng, ZHAO Long, LI Binhua, FENG Fei, XIE Hui, FANG Haijiang, ZHANG Yingjiu

2019, 39(4): 22-29. doi: 10.13394/j.cnki.jgszz.2019.4.0004

Abstract(273)

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Structure design and parameter optimization of PCD micro-milling cutter with large aspect ratio based on Deform

WANG Chen, HAO Xiuqing, LIU Linghui, CHEN Mengyue, HE Ning

2019, 39(4): 30-36. doi: 10.13394/j.cnki.jgszz.2019.4.0005

Abstract(348)

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Micro-milling technology is one of the most suitable micro-machining techniques for processing high aspect ratio microstructures, but the tools limit its development. In view of micro-milling of high aspect ratio microstructure, a new PCD miller was proposed with large length-diameter ratio and straight edges. The influence of tool structure on milling force and burr height was studied by Deform finite element simulation. Furthermore, the multi-objective response surface methodology is used to test three factors, namely the side edge clearance (SEC), the bottom edge clearance (BEC) and the bottom edge inclination angle (BEIA). Finally, the optimized structural parameters of micro-milling tool are obtained, which are SEC 30°, BEC 15°, BEIA 7°.

Optimization of EDM process parameters for PCD woodworking tools

DENG Fuming, WANG Han, LIU Jialin, ZHANG Zijun, YANG Xuefeng, YAN Xiao, LU Xuejun

2019, 39(4): 37-43. doi: 10.13394/j.cnki.jgszz.2019.4.0006

Abstract(294)

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The effects of pulse width (t_ON), peak current (I_IP), pulse gap adjustment (MA) and pulse interval (t_OFF) on the processing accuracy and efficiency of PDC were investigated. The optimum EDM process parameters were determined by orthogonal experiments as follows: t_ON 2 μs, I_IP10 A, MA 1 times, t_OFF 4 μs, processing time 458 s. The surface roughness R_a1 of YG layer was 1.04 μm and R_a2 of PCD layer was 0.59 μm. On this basis, the effects of PIKADEN high-voltage pulse control PP and high-voltage auxiliary power supply HP on the accuracy and efficiency of electrical machining were further investigated through single factor experiments and segmentation experiments. The results show that when PP is set to 11 and HP is set to 013, i.e. 1.5 A high voltage auxiliary current is added, the optimum EDM parameters of PDC are t_ON 4 μs, I_IP 10 A, MA 1 times and t_OFF 4 μs. The shortest processing time is 130 s with high processing accuracy, which is the YG layer R_a1 1.30 μm and the PCD layer R_a2 0.56 μm after processing. Compared with the optimum technological parameters determined by orthogonal experiments, the processing accuracy is not much different, but the processing efficiency is increased by 3.5 times.

Preparation and application of PCBN miniature milling cutter

ZANG Wenhai

2019, 39(4): 44-47. doi: 10.13394/j.cnki.jgszz.2019.4.0007

Abstract(333)

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Polycrystalline cubic boron nitride (PCBN) cutting tools have high hardness, high wear resistance, good thermal conductivity and low friction coefficient, as well as excellent chemical stability, thermal stability and processing red hardness. PCBN cutting tools could process high hardness, high strength and corrosion resistant steel efficiently and obtain high surface processing quality by milling. Based on the analysis of the design features and processing difficulties of PCBN miniature milling cutter, PCBN micro-ball-nose double helical-edged milling cutters were manufactured with neck shrinkage of 3 mm, diameter of 0.2 mm, 0.4 mm, 0.6 mm and 1.0 mm. Cutting experiments were carried out with a miniature milling cutter with diameter of 0.4 mm.The results show that the PCBN micro-milling cutter can process the mould steel, whose hardness is 50 HRC, with high quality and high efficiency. The surface roughness R_a of the mould is 0.101 μm and there is no negative surface, which meets the design standard.

Progress of research on testing and regulating of grain protrusion height of diamond abrasives

LI Zhengxin, YU Wei, WANG Lijing

2019, 39(4): 48-55. doi: 10.13394/j.cnki.jgszz.2019.4.0008

Abstract(411)

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Diamond grinding tools are widely used in aerospace, mold manufacturing, electronic devices, optical materials, medical devices, stone processing and other fields because of their advantages of high grinding efficiency, long service life and high precision of workpiece processing. The grinding function of the tools is realized by the exposed abrasive grain, the height of which from the surface of the bonding agent is defined as the protrusion height. Abrasive tools can only perform the best grinding performance when they have the appropriate protrusion height. Therefore, the testing and regulating technology of the protrusion height is very important for the preparation of high-performance grinding tools. In this paper, we reviewed the evaluation parameters, testing methods and control techniques of diamond protrusion height and analyzed the problems in the research field. Finally, we pointed out the future research direction of protrusion height test and control.

High-speed grinding stability determination of camshaft based on Simulink simulation

LUO Delong, DENG Zhaohui, LIU Tao, SHE Shuailong, LUO Chengyao, PENG Keli

2019, 39(4): 56-61. doi: 10.13394/j.cnki.jgszz.2019.4.0009

Abstract(366)

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Taking the stability of the camshaft high-speed grinding process system as the research object, the dynamic model of the camshaft and grinding wheel and support system of the grinding system is established. Through theoretical analysis and numerical calculation to identify the dynamic influencing factors of the grinding force, such as cam profile curvature radius and instantaneous grinding depth. Based on the established grinding dynamics model, the Matlab/Simulink flutter simulation model is built, and the corresponding grinding process parameters combination is selected from the stability blade diagram for numerical simulation analysis. The stability of the vibration displacement time domain map is simulated, which is compared with the grinding stability region of the stability leaflet, the effectiveness of the grinding dynamics model and numerical simulation method established is verified in this paper.

Influence of pore-forming agent content on grinding performance of resin-bonded silicon wafer thinning wheel

HUI Zhen, ZHAO Yanjun, ZHANG Gaoliang, ZHAO Jiong, DING Yulong, YE Tengfei, SUN Guannan, XIONG Huajun

2019, 39(4): 62-65. doi: 10.13394/j.cnki.jgszz.2019.4.0010

Abstract(433)

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In order to improve the thinning effect on the back of silicon wafer, a pore-forming agent was added into the resin-bonded silicon wafer thinning wheel. The effects of pore-forming agent content on the structure and grinding performance of resin-bonded grinding wheel were studied by volume density measurement, SEM observation and grinding experiments.The results show that with the increase of pore-forming agent volume fraction and the decrease of feeding ratio, the internal porosity of grinding wheel increases, and grinding experiments show that pore-forming agent can improve the surface quality of silicon wafer.When the volume fraction of pore-forming agent is 10% and the volume density feeding ratio is controlled at 75%, the resin-bonded silicon wafer thinning wheel has better comprehensive grinding performance. The fluctuation range of R_a, R_z and R_y values of the surface roughness of the silicon wafer ground by this wheel is small. Compared with the silicon wafer ground by the grinding wheel under other conditions, the surface consistent of the silicon wafer is good.

Research on edge chipping of silicon wafers with taping after diamond grinding

ZHANG Qian, DONG Zhigang, LIU Haijun, WANG Ziguang, KANG Renke, YAN Ning, ZHU Xianglong

2019, 39(4): 66-69. doi: 10.13394/j.cnki.jgszz.2019.4.0011

Abstract(391)

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Resin-bonded diamond grinding wheel was used to reduce the thickness of single crystal silicon wafer with film thickness of 80 μm and 160 μm to 400 μm. The effect of film thickness on the quality of silicon wafer was evaluated by measuring the edge collapse size of silicon wafer. The experimental results show that the silicon taping can effectively reduce the fragmentation rate of silicon wafer. When the silicon wafer is not taped, the average edge collapse size of the silicon wafer is 3.08 μm. When the taping thickness of the silicon wafer is 80 μm and 160 μm,the average edge collapse size of the silicon wafer is 4.61 μm and 3.60 μm, which means that silicon taping has a deteriorating effect on the edge collapse of silicon wafer, while the effect is small. The deterioration degree can be controlled within 20% when thick film is used. When the film-coated silicon wafer is thinned and ground with a 23 μm diamond grinding wheel, there is no significant difference in the edge collapse sizes of <110> crystal direction and <100> crystal direction of silicon wafer.

Effect of addition mode of forming additive on properties of ceramic CBN internal grinding wheel

WANG Zhiqi, YANG Wei, LI Henan, MU Longge, LIU Bin, XI Yaohui

2019, 39(4): 70-74. doi: 10.13394/j.cnki.jgszz.2019.4.0012

Abstract(319)

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Based on self-made low-temperature polymer forming aid, the effect of adding modes, namely unadded, particle addition and melt addition, on the bending strength of ceramic CBN test strips, the uniformity of ceramic CBN grinding wheel forming materials, the uniformity of wheel structure and the micro-structure and grinding properties of ceramic CBN internal grinding wheel were studied. The results show that when the polymer forming aid is added by melting, it can form a uniform coating on the surface of the CBN grinding wheel molding material after cooling, and that the looseness and uniformity of the molding material are obviously improved. When the additives are added in the form of granules and melting, the extreme difference of flexural strength of CBN strips are 34.02% and 73.77% lower than that of unadded strips respectively. The density differences of ceramic CBN internal grinding wheel are reduced by 56.83% and 79.14% compared with that of unadded grinding wheel, and the structures of grinding wheels are more uniform. When the polymer forming aid is added by melting, the ceramic CBN internal grinding wheel does not show the bell mouth when grinding the vane pump stator, and its service life is twice as long as that of the wheel without polymer forming additive.

Effect of hexagonal boron nitride content on properties of iron-based diamond abrasives

HAN Zhijing, XU Sankui, HAN Ping, ZOU Wenjun

2019, 39(4): 75-79. doi: 10.13394/j.cnki.jgszz.2019.4.0013

Abstract(364)

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The iron-based diamond abrasive tool test strip containing hexagonal boron nitride (hBN)was prepared by vacuum sintering.The effects of hBN content on hardness, bending strength, impact strength and wear ratio of the samples were studied. The morphology of the grinding surface was analyzed by electron microscopy, and the burning condition of the grinding surface was judged.The results show that the density, hardness, bending strength and impact strength of the abrasive tool samples decrease with the addition of hBN, with no hBN added is 6.57 g/cm³、85.5 HRB、253 MPa、113.0 J/mm²down to the volume fraction of hBN 11% is 5.31 g/cm³、44.5 HRB、103 MPa、99.5 J/mm² respectively down to 19.2%、48.0%、59.3%、11.9% , and the friction coefficient of the abrasive tool can be effectively reduced and the protrusion rate of the diamond in the abrasive tool can be improved by adding hexagonal boron nitride under the same grinding conditions, thus greatly reducing the burns of the abrasive tool in the grinding process and effectively improving the grinding quality of the workpiece.Grinding burn is minimal when the volume fraction of hexagonal boron nitride is 11%.

Application of PA1212 in resin bond grinding wheel for PCB tools

ZHANG Gaoliang, SHI Linfeng, ZHAO Yanjun, QIAN Guanwen, WANG Lihua, ZUO Donghua, ZHU Jianhui

2019, 39(4): 80-84. doi: 10.13394/j.cnki.jgszz.2019.4.0014

Abstract(326)

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Polyimide resin grinding wheel was improved by adding micron sized polyamide 1212 (PA1212). The durability, the lifetime and the surface quality of printed circuit board (PCB) tools before and after improving the wheel were studied by grinding tests. Results show that after adding PA1212, the durability of the grinding wheel for PCB tools is improved by 59.5%, lifetime increased by 71.2%. It is also found that the probability of collapse at tool edge during grinding is greatly reduced and that the surface texture of the tool is more uniform.

Ultrasonic assisted grinding of SiC_f/SiC composites

KANG Renke, ZHAO Fan, BAO Yan, ZHU Xianglong, DONG Zhigang

2019, 39(4): 85-91. doi: 10.13394/j.cnki.jgszz.2019.4.0015

Abstract(921)

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SiC fiber reinforced SiC ceramic matrix composites (SiC_f/SiC) have problems such as poor machining quality and severe tool wear. To study these problems, SiC_f/SiC composites were processed by ultrasound-assisted grinding, and the grinding force, surface morphology and three-dimensional surface roughness were tested and explored. The removal mechanism of materials in ultrasound-assisted grinding was analyzed. The results show that ultrasonic assisted grinding can effectively reduce grinding force. The ultrasonic effect promotes the fracture of SiC fibers and the formation of shorter fibers to be removed, which reduces the fiber breaking and peeling and improves the surface quality, but the large amplitude of vibration is not conducive to the improvement of the surface quality.

Investigation on formation mechanism of nodulation on back of electrodeposited ultra-thin diamond cutting blade

ZHU Xiaowei, SHAO Junyong, WANG Yongbao, WANG Zhan, LIU Jianshuang, LI Yuanyuan

2019, 39(4): 92-96. doi: 10.13394/j.cnki.jgszz.2019.4.0016

Abstract(312)

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Scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive spectrometer (EDS) were used to observe and analyze the morphology of nodulation on the back of the blade and the surface morphology and composition evolution during the treatment of the aluminum alloy matrix before electrodeposition, and the formation mechanism of nodulation on the back of the blade was investigated. The results show that during the pretreatment, the aluminum alloy around the precipitates on the surface of aluminum alloy matrix dissolve gradually, and the precipitates fall off. After twice zinc dipping, the aluminum matrix surface generates 0 to 6 μm holes. The nickel deposit in the holes during the electrodeposition of nickel-diamond composite. After removing part of the aluminum alloy matrix, the 0 to 6 μm bumps are formed on the back of the deposit layer, i.e. nickel nodules.

Development of consolidated diamond wire saw cutting technology for brittle materials

GAO Hang, KONG Weimiao

2019, 39(4): 97-102. doi: 10.13394/j.cnki.jgszz.2019.4.0017

Abstract(495)

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Brittle materials have important applications in optical components industry, semiconductor industry, photovoltaic industry, stone industry and other fields. By analyzing the common cutting methods of brittle materials, the cutting principle of consolidated diamond wire saw, the manufacturing technology of consolidated diamond wire saw and the processing methods of consolidated diamond wire saw machine tools, the effects of different processing methods on the cutting quality of brittle materials were studied. The results show that the one-way circular diamond wire saw machine tool works for ultra-long time with high speed. The wire saw speed is stable. It can realize precision and ultra-precision cutting of hard and brittle materials, which is the mainstream of future development. The circular diamond wire saw is an important part of the one-way circular diamond wire saw machine tool, and its processing and manufacturing technology is the difficulty for future development.

NC machining of axisymmetric aspherical glass lens with diamond grinding head

ZENG Kai, CHEN Hongkun, SHEN Jianyun, WU Xian, LU Lang

2019, 39(4): 103-109. doi: 10.13394/j.cnki.jgszz.2019.4.0018

Abstract(308)

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In order to improve the shape accuracy of axisymmetric aspheric lens and reduce its finishing cost, the K9 optical glass was milled with a small diamond grinding head under different processing parameters and NC tool path conditions. The profile accuracy of the lens is measured by a three-coordinate measuring machine. The normal profile error of the aspheric lens is calculated by measuring data points, and is compensated by NC machining of the effective cutting radius of the grinding head.The experimental results show that when the NC tool path is parallel finishing and contour finishing,the maximum profile deviation PV and the mean error RMS are 54.48 and 22.88 μm, 98.46 and 28.88 μm, respectively.The surface accuracy of aspheric lens can be improved by optimizing the effective cutting radius of diamond grinding head. The optimized PV and RMS values of aspheric lens profile accuracy after parallel finishing are 44.52 and 7.37 μm, respectively.

2019 Vol. 39, No. 4

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