CN 41-1243/TG ISSN 1006-852X

2020 Vol. 40, No. 1

Display Method:
2020, 40(1): 1-4.
Study status and future prospects on ultrasonic assisted grinding of hard and brittle materials
DING Kai, LI Qilin, SU Honghua, CHEN Yurong
2020, 40(1): 5-14. doi: 10.13394/j.cnki.jgszz.2020.1.0001
Hard and brittle materials have some significant characteristics such as high strength, high hardness and low density.However, just because of high hardness and brittleness, great damage and low efficiency are the dramatic problems for these materials when processed by traditional methods.By contrast, ultrasonic assisted grinding(UAG)possesses some advantages such as lower grinding force and better processing quality.These characteristics bring particular advantages for machining hard and brittle materials.Considering different vibration dimensions and location positions between vibration direction and grinding surface, grinding mechanisms and performances of different kinds of UAG are summarized.On the base of these analysis, study of ductile-regime grinding mechanisms, matching performance between ultrasonic vibration and grinding parameters are discussed for UAG of hard and brittle materials.In addition, future prospect about research areas worth paying more attention to during UAG is analyzed.
Design and application of large load amplitude transformer in ELID compound internal grinding system assisted by ultrasonic vibration
JIA Xiaofeng, ZHAO Bo
2020, 40(1): 15-23. doi: 10.13394/j.cnki.jgszz.2020.1.0002
A theoretical design, followed by optimization, of the amplitude transformer was carried out, which had longer small end for driving metal bonded diamond wheel with large size and heavy mass, to solve the problem of acoustic system design in ultrasonic vibration assisted ELID compound internal(UAEI)grinding of hard & brittle materials such as ceramics.Based on the propagation law of elastic wave in the medium, the value selection scheme of the amplitude transformer was determined by MATLAB, and then the scheme that met the requirements was selected according to both processing requirements and ANSYS modal analysis.Then the zero order algorithm was used to further optimize the processing, and the size of the amplitude transformer that met the requirements of geometric size, stress and vibration frequency was obtained.The vibration characteristics of the designed amplitude transformer are tested, whose resonance frequency error is within 0.192% to 1.824%, satisfying the expected design requirements.The machining characteristics of the developed UAEI grinding system are tested and compared with those of ELID.The surface roughness of the workpiece is reduced by 44.2%, and that the 3D shape of the workpiece is more flat with improved surface of the grinding wheel.
Study on machining quality of zirconia ceramic hole grinding based on rotating ultrasound vibration
WANG Zongwei, CONG Yan
2020, 40(1): 24-28. doi: 10.13394/j.cnki.jgszz.2020.1.0003
Aiming at the problems of poor processing quality and high processing cost of small holes in ceramics, a rotary ultrasonic assisted grinding process for small holes in zirconia ceramics was designed.Firstly, the principle of rotary ultrasonic machining was analyzed.Then, under the condition of ultrasonic vibration, the single factor small hole grinding experiment of zirconia ceramics was carried out by using diamond tools.The morphology of the inner wall of the small hole was analyzed and the roughness was measured.Finally, the influence of spindle speed, ultrasonic power and feed speed on the surface roughness of the small hole was studied.The results show that, compared with conventional grinding methods, the surface quality and residual stress of small holes are greatly improved and that the machining accuracy is obviously improved with surface roughness decreased by 52% under the condition of 300 W rotary ultrasonic assisted machining.
Study on sub surface damage of BK7 glass by ultrasonic vibration of diamond abrasive
2020, 40(1): 29-33. doi: 10.13394/j.cnki.jgszz.2020.1.0004
In view of the problems when grinding optical glass, such as the difficulty in machining, the poor surface quality of the workpiece and the serious internal damage of the workpiece, an ultrasonic vibration assisted machining method is proposed to study the engraving of BK7 glass.Firstly, a constitutive model of BK7 glass material is established by using the finite element software.Then the damage mechanism of the glass matrix after ultrasonic vibration of diamond abrasive is analyzed.Finally, an experiment is designed to study the influence of ultrasonic vibration power, speed and depth on the subsurface crack.The results show that the maximum depth of subsurface crack in ultrasonic etching is 19.7% lower than that in ordinary etching.With the increase of etching speed, the maximum depth of subsurface crack at the bottom of the groove increases gradually.With the increase of groove cutting depth, the maximum depth of subsurface crack increases gradually as a whole, and obvious classification occurs.
Carbon nanowalls modifying single crystal diamond surface by ECR microwave plasma
HENG Fan, LIAO Xuehong, CAO Wei, FU Qiuming, XU Chuanbo, ZHAO Hongyang, MA Zhibin
2020, 40(1): 34-38. doi: 10.13394/j.cnki.jgszz.2020.1.0005
Carbon nanowalls were modified on the surface of high temperature and high pressure single crystal diamond by electron cyclotron resonance(ECR)microwave plasma under CH4/H2system in this paper.The plasma emission spectroscopy was used to study the variation of the spectral intensity of the CH4/H2 ECR plasma in different working pressures and CH4 concentrations.The micro structure of the single crystal diamond was analyzed by scanning electron microscopy(SEM)and the effects of pressure and CH4 concentration on the modification results of carbon nanowalls were further studied.The results show that the orientation of carbon nanowalls is greatly affected by the working pressure.The carbon nanowalls grown under low pressure(0.07 Pa)have vertical orientation, and the surface of the diamond also has vertical etched morphology.At high pressure(5 Pa), the underlying carbon nanowalls have poor orientation.At the same time, the critical CH4 concentration of carbon nanowalls growth is also related to the working pressure.The critical CH4 concentration of carbon nanowalls growing under low pressure is higher.When the working pressure is 0.07 Pa, the critical CH4 concentration of carbon nanowalls growth is 3%.When the working pressure is increased to 5 Pa, the critical CH4 concentration of carbon nanowalls growth is reduced to 1%.And the density of carbon nanowalls increases proportionally with CH4 concentration.
Research status of boron-doped diamond
QI Lixia, CAI Yule, WANG Yuchang
2020, 40(1): 39-45. doi: 10.13394/j.cnki.jgszz.2020.1.0006
The structure characteristics of boron-contained diamond and the existing forms of boron atoms in diamond single crystals are introduced in this paper.The electrical properties and heat resistance of boron-contained diamond single crystals are illustrated.The preparation methods and main problems of boron-contained diamond single crystals in industry are summarized.The development trend of boron-contained diamond is prospected.
Fabrication TiC/Ti3SiC2-diamond composites by spark plasma sintering using different binder
ZHANG Lingjie, ZHANG Wangxi, LIANG Baoyan
2020, 40(1): 46-49. doi: 10.13394/j.cnki.jgszz.2020.1.0007
TiC/Ti3SiC2 bonded diamond composites were fabricated by spark plasma sintering using Ti/Si/2TiC and Ti3SiC2 powders as binder materials.Effect of binder material and holding time on the phase composition, microstructure and grinding properties of composites were studied.The result shows that there forms amounts of Ti3SiC2 when using Ti/Si/2TiC as binder with a holding time of 1 min, and the TiC/Ti3SiC2 bond has a good bond with diamond with no pores.When the holding time is 5 min, Ti3SiC2 decomposes and the main phase of the matrix is transformed to TiC and a certain amount of Si.The diamonds are etched then to form uneven surface.When Ti3SiC2 is used as the binder, the composite decomposes seriously to form TiC and Si.There is a transition layer with a thickness of about 15 μm between diamond and the matrix.In conclusion, the grinding ratio of the sample from Ti/Si/2TiC binder with a holding time of 1 min reaches the maximum value of 1 128, while the grinding ratios of the samples from Ti3SiC2 binder with holding time of 1 min or 5 min were about 100.
Study on mechanical properties of nickel-plated layer and abrasive holding force of electroplated diamond wire saw
XIE Qian, GE Peiqi, MENG Jianfeng, BI Wenbo, MA Xiaobin, ZHENG Chuxi, GONG Yang
2020, 40(1): 50-55. doi: 10.13394/j.cnki.jgszz.2020.1.0008
The mechanical properties of nickel coating on electroplated diamond wire saw are directly affected by electroplating process parameters, which are difficult to determine.Electroplating specimens were prepared according to the electroplating process of diamond wire saw.The mechanical properties of the specimens were tested by nanoindentation/scratch tester and X-ray diffractometer.The hardness, modulus of elasticity, residual stress of nickel-plated layer and the bonding strength between nickel-plated layer and wire saw matrix were obtained.The holding force of nickel plating on diamond abrasive particles was calculated.According to the mechanical parameters of nickel coating obtained from the test, the finite element model of abrasive holding force is established and simulated.The simplified calculation results are in good agreement with the simulation results.
Effect of sintering system on cellular structures of vitrified bond diamond wheels
MIAO Weipeng, DING Yulong, LUO Miaodi, XIONG Huajun
2020, 40(1): 56-60. doi: 10.13394/j.cnki.jgszz.2020.1.0009
Vitrified bond ultrafine diamond wheels with cellular structures were prepared by space placeholder method and solid particles sintering.The effect of sintering system on the cellular structures of the wheels was studied via the microstructure, the porosity and the bending strength of the wheels.The results show that the optimum sintering temperature of manufacturing ceramic bond ultrafine diamond wheels with cellular structures is 750℃,and the holding time is 90 min, thus the porosity and the bending strength of the prepared samples are 78% and 15 MPa.
Effect of dicing blade formulation on chipping and cracking of GaAs wafers
ZHANG Di, CUI Qing′an, ZHU Xiaowei, YAN Heliang
2020, 40(1): 61-66. doi: 10.13394/j.cnki.jgszz.2020.1.0010
The effect law of dicing blade formulations on the chipping and cracking quality of GaAs wafers was studied by designing of experiment method, which is to cut wafers through blades with different formulations, and to test the crack size on the top, back or side faces.The results show that the abrasive grain size of the blade is closely related to the cutting quality of GaAs wafer.The finer the abrasive grain size, the smaller the size of the cracks on the top, back or side.The correlation of abrasive concentration or bond strength to GaAs wafer cutting quality is not significant.Therefore, the cutting quality could be enhanced by adopting smaller abrasive and adjusting abrasive concentration and bond strength.
Effect of lapping temperature on performance of hydrophilic fixed abrasive pad
ZHANG Jiaqian, SHEN Gongming, TANG Chao, ZHU Yongwei
2020, 40(1): 67-73. doi: 10.13394/j.cnki.jgszz.2020.1.0011
The rise of lapping temperature causes a change in the modulus of the resin matrix, thereby affecting the processing performance of the hydrophilic fixed abrasive pad.The transient temperature field of hydrophilic fixed abrasive pad at different slurry temperatures was simulated by finite element analysis.The swelling rate and the amount of slurry wear were adopted to characterize the properties of the resin matrix for fixed abrasive pad.The processing performance of fixed abrasive pad for quartz glass at different lapping temperature was explored.The results show that with the rise of lapping temperature, the temperature distribution range of the resin matrix also changes, the swelling rate and the amount of slurry wear of the pad matrix reach 1.43% and 2.5 mg, respectively.Experimental results show that the increase in temperature causes the matrix modulus to decrease, the material removal rate and average surface roughness are improved, which are 8.2 μm/min and 69.9 nm, respectively.Appropriately increase of lapping temperature can improve the processing performance of the fixed abrasive pad to a certain extent.
Effect of environmental friendly complexing agent and oxidant on CMP of aluminium alloy under low pressure
ZHU Yuguang, WANG Yongguang, NIU Shiwei, XIE Yujun, LEI Xiangyu
2020, 40(1): 74-78. doi: 10.13394/j.cnki.jgszz.2020.1.0012
Effects of oxidizer hydrogen peroxide(H2O2)and complexing agent chitosan oligosaccharide(COS)on material removal of aluminium alloy were investigated in alkaline slurry by using atomic force microscope(AFM), X-ray photoelectron spectroscopy(XPS)and nanoindentation tests.In addition, the chemical effect of H2O2 and COS occurred in CMP process was discussed.The results show that the material removal rate increased as the COS concentration increased when the mass concentration of H2O2 was 2%.It can obtain remarkably smooth surface Ra=2.5 nm and 861 nm/min removal rate when the mass concentration of COS reached 0.32%.The material removal rate was enhanced by the increase of H2O2 concentration when the mass concentration of COS was 0.5%.After reaching the maximum value, the material removal rate began to decrease.The surface roughness was 3.52 nm and the material removal rate was 840 nm/min when the mass concentration of H2O2 reached 1.2%.A weak passive layer is mainly consisted by Al-COS、Al2O3 and Al(OH)3 when COS was added.
Research progress in chemical mechanical polishing of single crystal SiC substrates
DENG Jiayun, PAN Jisheng, ZHANG Qixiang, GUO Xiaohui, YAN Qiusheng
2020, 40(1): 79-91. doi: 10.13394/j.cnki.jgszz.2020.1.0013
Single crystal SiC has become an important epitaxial layer material because of its excellent physical and chemical properties.It is widely used in satellite communications, integrated circuits, and consumer electronics.The growth of an epitaxial layer of SiC wafer requires an ultra-smooth, flat surface with low process surface damage and residual stress on the single crystal SiC surface.The surface quality determines the subsequent epitaxial layer quality and ultimately affects the performance of the device.Chemical mechanical polishing(CMP)is a common and effective method for ultra-precision machining of single crystal SiC substrates.We summarize the research status of the single crystal SiC substrate in chemical mechanical polishing processing, categorize and analyze the advantages and disadvantages of various categories and limitations of the application according to the principle of processing, and points out the development prospects in the field of chemical mechanical polishing.
Study on influence of cutting vibration on CBN tool wear based on finite element theory
2020, 40(1): 92-98. doi: 10.13394/j.cnki.jgszz.2020.1.0014
The effect of cutting vibration on tool wear in cutting titanium alloy Ti-6Al-4V with CBN tool was studied.By using finite element analysis technology, orthogonal experiments were designed to analyze the effects of vibration amplitudes and frequencies in different directions on tool surface stress and tool temperature, so as to study tool wear under cutting vibration conditions.The results of finite element simulation showed that the influence of X-direction vibration on the stress and temperature of the tool surface was limited.There was no obvious regularity.The wear of the tool was not aggravated by X-direction vibration condition.The influence of Y-direction vibration on the stress and temperature of the tool surface was greater.The stress and temperature of the tool surface increased with the vibration amplitude and frequency in Y-direction.When the vibration occurred in both X and Y directions, the stress and temperature on the tool surface increased with the increase of vibration amplitude and frequency, which was characterized by severe tool wear.Cutting experiment was carried out.It was found that the vibration had a great influence on the tool wear, which was basically consistent with the results of the finite element analysis.
Analysis on oxidation and diffusion wear of PCBN tool in cutting nickel base alloy
HU Xiaolong, SHAO Fang, WANG Renwei
2020, 40(1): 99-102. doi: 10.13394/j.cnki.jgszz.2020.1.0015
The wear mechanism of PCBN tool when cutting nickel-based alloy was studied by cutting experiments.The difference of the reaction mechanism of oxidative wear on the rake face and flank face of the tool was analyzed by the Gibbs free energy function method.The main oxidation reaction equation of oxidative wear was obtained.The solubility of boron nitride in different elements of nickel-based alloy was calculated by thermodynamic dissolution theory model.The difference of the mechanism of diffusion process between rake face and flank face was obtained.The results show that both the rake face and flank face of the tool have serious oxidation wear and diffusion wear.Diffusion and dissolution of elements increase the occurrence of diffusion wear.
Finite element simulation of sawing force for impact-resistant diamond saw blade——Take the circular saw blades inlaid with copper nails in the bottom holes of keyhole sink as an example
HU Huan, ZHANG Yuncai, LI Chunlin, ZHAO Lei
2020, 40(1): 103-107. doi: 10.13394/j.cnki.jgszz.2020.1.0016
A finite element analysis model of the cutting force of the impact resistant diamond saw blade was established.The numerical simulation and comparative study of the cutting force of the blade were carried out on two kinds of tooth structures, namely the conventional keyhole sink and the new keyhole sink in which there were copper nails embedded at the bottom.The simulation results show that under the same load, the deformation and stress of the saw blade with copper nail embedded at the bottom hole are significantly improved compared with those of the traditional keyhole sink.The deformation of the saw blade is reduced by 6.36%, and the first and third principal stresses are reduced by 38.04% and 41.36% respectively.Therefore, by embedding copper at the bottom hole of the keysink could improve the impact resistance of saw blade, thus making it more suitable for applications with larger loads.