金刚石与磨料磨具工程

A brief analysis on economic situation of China′s superabrasives industry in the first half of 2017

SUN Zhaoda, LI Zhihong, WEN Shuying

2017, 37(6): 1-11,18. doi: 10.13394/j.cnki.jgszz.2017.6.0001

Abstract(319)

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Abstract:
The operation situation of superabrasives industry is briefly analyzed according to 5 tables and 21 figures, which cover some data of Chinese macro economy, the main indexes of the industry, the productions, imports and exports of superabrasives and the semi-annual reports of listed companies in the first half of 2017.It is found that indexes of the industry, such as product sales revenue (increase 22%), export value (increase 20%) and total profit (increase 16%), all increase by more than 10%.Export volume is grown by 25%and its value grown by 18% according to China Customs statistics.All these data indicate that markets, both domestic and international, are improved, in reverse to the decline of the industry economy in previous two years.They also shows the recovery of the industry economy, which is due to transformation and upgrading effect and product structure improvement.However, the inventory, which basically remains unchanged, still faces a heavy pressure.According to the international market, China's synthetic diamond and diamond saw blade have reached the advanced level of the world while grinding wheel and cutting tool share little portion, which means that there is a huge space for their innovation and development.

Efficient lapping zirconia ceramic back with fixed diamond aggregation pad

WANG Zikun, LING Shunzhi, HUANG Daowan, CHEN Jiapeng, LI Jun, ZHU Yongwei

2017, 37(6): 12-18. doi: 10.13394/j.cnki.jgszz.2017.6.0002

Abstract(326)

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High efficiency and low damage lapping of zirconia ceramic back is the precondition of its applications in 5 Gcommunication.The hard and brittle characteristics of zirconia materials caused serious wear of abrasive particles, so the diamond aggregation abrasives were chosen to prepare the fixed abrasive pad (FAP).A comparison of lapping performance between diamond aggregation FAP and single diamond FAP was made.The role of SiC particles in the slurry in the self-dressing process of FAP was explored.Resultsshow that using diamond aggregation pad assisted by silicon carbide slurry, can obviously improve the lapping speed and the surface machining quality.When adopting the grain size of diamond aggregation in FAP is 230/270 and the slurry with particle size of green SiC is from 3 to 5 μm, the material removal rate of zirconia ceramic can reach more than 2.5 μm/min with average surface roughness R_a is 74.9 nm.

Study on grinding KDP crystal with the vertical spindle face grinding machine

QU Meina, JIN Tan, GUO Zongfu, LU Ange

2017, 37(6): 19-23,33. doi: 10.13394/j.cnki.jgszz.2017.6.0003

Abstract(311)

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Potassium dihydrogen phosphate (KH₂PO₄ or KDP), an recognized optical crystal, has been widely used in laser nuclear fusion projects due to its good quality of large electro-optic coefficient and large diameter (≥ 400 mm).From growth to processing into optical element, it requires procedures of cutting, precision machining, ultra-precision machining, coating and so on, and the processing period is long.In this paper, the grinding process of the KDP crystal is carried out using the vertical spindle face grinding machine.The influences of different particle sizes resin bonded diamond wheels (D7, D36, D91, D151) on the surface roughness and surface micro-topography under different processing parameters (spindle speed, feed speed, grinding depth) are compared.The feasibility of KDP crystal grinding is studied which lays the foundation for realization of grinding instead of turning (polishing) and shortening the manufacturing cycle of KDP optical elements.

Study on parameters of improving fluid jet polishing removal efficiency

GUO Zongfu, JIN Tan, LI Ping, QU Meina, LU Ange

2017, 37(6): 24-33. doi: 10.13394/j.cnki.jgszz.2017.6.0004

Abstract(395)

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Abstract:
The application of fluid jet polishing (FJP) technology, who has unique advantage in machining ultra precision optical elements, is limited due to low removal efficiency.The effects of nozzle diameter and jet pressure on removal function, removal efficiency and deterministic modification are analyzed by experiments and simulations.It is experimentally ascertained that the removal efficiency increases with the increase of nozzle diameter in a certain size range, and that the removal efficiency increases slower when nozzle diameter increases beyond the range.The width change of the removal function is much larger than that of the nozzle diameter.The depth of the removal function increases exponentially with the increase of the jet pressure, and the profile of the removal function changes from W shape to double W shape.By establishing the rotation function to simulate the eccentric rotating jet method, it is proved that the removal function after deformation has good applicability in deterministic polishing process and the method can be directly applied to the deterministic polishing of the ultra precision surface using a vertical jet.

Epitaxial growth of diamond single crystal on surface of milled diamond seeds at high pressure and high temperature

GAO Feng, REN Guozhong, YANG Guangmin

2017, 37(6): 34-36,40. doi: 10.13394/j.cnki.jgszz.2017.6.0005

Abstract(289)

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Diamond single crystal was epitaxially grown on the surface of diamond seeds with rough planes at high pressure and high temperature (HPHT) conditions.Fe₈₀Ni₂₀ alloy powder was used as catalyst/solvent and natural flake-like graphite was used as carbon source.Diamond single crystals were grown on the diamond seeds at 4.8 GPa and 1500 K.The morphology of the samples was observed by SEM.The mechanism of diamond growth with smooth planes from original seed with rough planes was studied.

Study on integration process of synthetic diamond purification and graphite oxide preparation

YANG Biye, XU Hongliang, LI Zhenyu, WANG Haichao, DING Saisai

2017, 37(6): 37-40. doi: 10.13394/j.cnki.jgszz.2017.6.0006

Abstract(327)

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Magnetic separation method, Hummers method and sedimentation separation method were used to purify the synthetic diamond tails obtained through shaking table separation.The X-ray diffractometer, Raman spectrometer and scanning electron microscope were used to characterize the phase compositions and the microstructures of the obtained samples.The results indicate that the obtained diamond has high purity and that the recovery rate is close to 100%.At the same time, the graphite in the synthetic diamond tails is converted to graphite oxide, which saves resources and turns waste into treasure.

Fabrication of porous structure on diamond abrasive surface

FAN Bo, XU Shuai

2017, 37(6): 41-44. doi: 10.13394/j.cnki.jgszz.2017.6.0007

Abstract(410)

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SEM and EDS characterization have provided insight into the chemical composition and microstructure of a particular kind of HPHT synthesized diamond abrasive.Fine dispersion of micron titanium compound particles was observed both on surface and inside the diamond grains.The particles were found to be removed from the grain surface by oxidation and subsequent acid corrosion.After such treatment, porous structures were formed on the diamond grain surface.The possible beneficial effect of the porous structure, such as self-sharpening performance and high grinding efficiency of diamond wheel is suggested.

Development overview of composite superhard material industry in China

MA Shanshan, FANG Haijiang

2017, 37(6): 45-48,61. doi: 10.13394/j.cnki.jgszz.2017.6.0008

Abstract(326)

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Abstract:
This paper gives an overview of 20 years development of the composite superhard materials in China's superhard material industry.It expatiates the progress in the high speed development period & transformation and upgrading period and the future development trend for the three main categories products in composite superhard materials field:PDC for drilling & engineering, PCD & PCBN cutters, PCD die blanks for wire drawing.

Research of polycrystalline diamond compact having non-planar surfaces for oil drilling

ZHAO Dongpeng, MA Shanshan, NIU Tongjian, LI Sicheng, ZHANG Chunlin, FANG Haijiang

2017, 37(6): 49-52. doi: 10.13394/j.cnki.jgszz.2017.6.0009

Abstract(292)

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Utilizing domestic hinge-type cubic press, the un-planar surfaces polycrystalline diamond compacts used in oil drilling were synthesized under high temperature, high pressure and subsequent processing conditions, including 3-ridge, 4-ridge and 5-ridge cutters.Meanwhile, the influences of cutting edge and vertical direction angle on the performances of 3-ridge, 4-ridge and 5-ridge cutters were investigated.The laboratory testing results show that the wear resistance, loading force and fatigue resistance of the 3-ridge, 4-ridge and 5-ridge cutters (the angle between the cutting edge and vertical direction is 90°) are the same as that of the ridge-cutter;compared with flat cutters, their wear resistance and fatigue resistance are increased by about 58.6%and 51.8%respectively, and the loading force is reduced by 41.9%.When the 3-ridge, 4-ridge and 5-ridge cutters' angles between the cutting edge and vertical direction are 99°, the average values of their fatigue resistances are about 30% higher than that of 90° under the same conditions of wear resistance and grinding loading force, and about 95.7% higher than that of the flat cutters.

Study on grinding temperature of titanium alloy by electrostatic spraying coating wheel

HUO Wenguo, CAI Lanrong, WANG Xiaowei, SHAO Juan

2017, 37(6): 53-56. doi: 10.13394/j.cnki.jgszz.2017.6.0010

Abstract(282)

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Abstract:
In order to deal with the hard machining of titanium alloy, the electrostatic spraying grinding wheel coating system and experimental grinding wheel were designed.The experiments of dry grinding titanium alloy were carried out.The influence of grinding conditions on grinding temperature was analyzed.The results show that the titanium alloy was machined by electrostatic spraying solid lubricant coated grinding wheel under the same processing conditions, when the grinding depth is 0.2 mm, the grinding temperature of coating wheel is no more than 600℃, but close to 900℃ with no-coating grinding wheel.The grinding wheel coating with solid powder electrostatic spraying can effectively reduce grinding temperature.

A new type of grinding wheel manufacturing technology for rubber roller

BIAN Huaying, WANG Xuetao

2017, 37(6): 57-61. doi: 10.13394/j.cnki.jgszz.2017.6.0011

Abstract(310)

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Based on the patent ZL 201510030023.1 "A new type of grinding wheel for grinding rubber rollers and its manufacturing method and technology", the mechanism of pores action in the new type of grinding wheel is discussed.Compared with the traditional grinding wheel, the new grinding wheel has good processing ability when it grinding the rubber rollers, and it is not easy to cause pore blockage, no chatter and scratch marks, which is conclusive to improving the processing quality and improving the labor efficiency.Through the test sample grinding application feedback, the prorosity of the new grinding wheel reaches to 70%~80%, the revolving velocity is 120 m/s, which is 16% and 20% higher than that of the general large pore silicon carbide wheel respectively.The surface roughness of the workpiece is increased in a way, and the repair periods is prolonged for more than 2 months.Targeted selection of corundum hollow spheres can produce new grinding wheels that conform to the design and effectively avoid some problems of traditional grinding rubber roller wheels, such as black heart of silicon carbide wheel with large pores, low working strength, and additives that are unfriendly to the environment.At the same time, the production process of the new type of grinding wheel is stable and reliable, and it is easy to be popularized and applied.

Research on the influence of the machinability of work-piece material on the economic performance of index able cemented carbide tools

HE Genghuang, LI Lingxiang, CHENG Cheng, ZOU Lingli, WU Mingyang

2017, 37(6): 62-69. doi: 10.13394/j.cnki.jgszz.2017.6.0012

Abstract(341)

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The cutting experiments of high quality medium carbon steel 45^# and GCr15 bearing sleeve are conducted using two kinds of carbide cutting inserts with different grades and different groove profile.According to the metal cutting principle and analytical method of processing economics, the action mechanism of machinability of parts to production efficiency and production cost is studied with the goal of revealing the regular.Then the inner link of insert service life, machinability coefficient of work-piece and global hardness is explored through cutting experiments.The researches show that the processing costs will be indexed reduce as the improvement of machinability coefficient, insert service life lengthening and drop of work-piece hardness;meanwhile, the production efficiency will get doubled.In the research process, the quantitative relation curve between insert service life and processing economy is obtained to implement the quantifiable objectives of cutting process optimization.The research data and methods can provide methods and data support for the optimization of cutting process and tool design.

Research progress of surface topography detection on grinding wheel

LIU Wei, SHANG Yuanyuan, DENG Chaohui, LIU Rentong

2017, 37(6): 70-78,86. doi: 10.13394/j.cnki.jgszz.2017.6.0013

Abstract(332)

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The grinding performance mainly depends on the surface topography characteristics of grinding wheel.The accurate detection of grinding wheel surface topography will not only help to further understand the grinding mechanism, but also be an indispensable prerequisite for grinding wheel surface modeling and grinding simulation.Therefore, typical surface topography detection methods for grinding wheel are summarized and the basic principles of these methods are briefly described, as well as their advantages and disadvantages analyzed.The current situation of surface topography detection methods for grinding wheel at home and abroad is analyzed.In the end, the existing problems are pointed out, and the development prospect is prospected.

Uncertainty evaluation on determining aluminum oxide in vitrified bond by ICP-OES

CHEN Xuewei, LUO Miaodi, HU Yujing, FENG Bingqiang

2017, 37(6): 79-82. doi: 10.13394/j.cnki.jgszz.2017.6.0014

Abstract(327)

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ICP-OES, which is short for inductively coupled plasma optical emission spectrometry, is frequently used to determine Al₂O₃ content in ceramic bonds.To improve the accuracy, comparative tests were implemented to study the causes of uncertainty and evaluate it.The uncertainty caused by test repeatability, solution concentration, liquid volume, dilution degree and sample weighing was assessed.The combined uncertainty and expanded uncertainty was calculated based on an international method.Assessment shows that test repeatability and solution concentration affect the uncertainty most.In conclusion, when determining the content, parallel repetitive measurement should be conducted with special attention paid to solution concentrations when drawing a standard curve.

Uncertainty evaluation on determining lithium oxide in vitrified bond by FAAS

LUO Miaodi, CHEN Xuewei, FENG Bingqiang, HU Yujing

2017, 37(6): 83-86. doi: 10.13394/j.cnki.jgszz.2017.6.0015

Abstract(249)

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Abstract:
FAAS, which is short for flame atomic absorption spectrometry, is a method widely used to assess Li₂O₃ content in vitrified bond.To improve the accuracy, comparative tests were implemented to study the uncertainty caused by test repeatability, linear regression of standard curve, liquid volume, dilution degree and sample weighing.The combined uncertainty and expanded uncertainty was calculated based on an international method.Resultsshow that test repeatability and linear regression of standard curve affect the uncertainty most.In conclusion, when determining the content, parallel repetitive measurement should be conducted with special attention paid to solution concentrations when drawing a standard curve.

Study & preparation of compound pressure transmitting medium for pressless split-sphere high pressure apparatus

LONG Zhengxin, ZHENG Jianfeng, LI Peipei, XIE Ergaizhenweinuogeladuofu, CAO Dahu

2017, 37(6): 87-90. doi: 10.13394/j.cnki.jgszz.2017.6.0016

Abstract(263)

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When synthesizing gem-grade diamonds with pressless split-sphere high pressure apparatus (BARS), the requirements on relative density of pressure transmitting medium is pretty high.To enhance the efficiency of pressure transmitting, the preparation of a compound medium, ZrO₂-NaCl, is studied through experiments.The influence of relative density on sealing effect and chamfering is analyzed and the pressure transmitting ability is enhanced by compound ZrO₂ with NaCl.It is found that the compound medium has higher transmitting efficiency than pyrophyllites and that only when the relative density is 92%, the apparatus could work safe and stable.It also requires additional sealing edge.In the end, 2-ct VS-level yellow gem-grade diamond single crystal is prepared on self-made BARS with ZrO₂-NaCl as pressure transmitting medium.

2017 Vol. 37, No. 6

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