Advances in Abrasive Technology IX

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Authors: Akihiko Kubo, Junichi Tamaki
Abstract: A solid-type diamond rotary dresser consisting of a CVD diamond disc is developed and applied to the dressing of a vitrified CBN grinding quill for internal grinding. This dresser has a feature not found in the other discrete-type rotary dressers used thus far, in which it continuously contacts the grinding wheel and leaves a spiral on the grinding wheel surface. The solid-type diamond rotary dresser was mounted on a low-speed spindle supported by journal bearings, and its dressing performance was compared with those of two discrete-type rotary diamond dressers: a dressing roll on which surface single diamond grains are brazed and a dressing roll made of a metal-bonded diamond wheel. It is found that the solid-type diamond rotary dresser tends to bring about rough grinding conditions among the three dressers.
187
Authors: Wen Chen Chou, Choung Lii Chao, Hsi Hsin Chien, Kung Jeng Ma, Hung Yi Lin
Abstract: ZnO/Diamond structure has attracted a lot of attentions and heavy investment recently just because diamond has the capability of producing very high surface acoustic wave (around 10,000m/s). In this present study, the microwave chemical vapor deposition (CVD) method was employed to produce diamond films on silicon single crystal. Thermo-chemical polishing experiments were then conducted on the obtained diamond films. The underlying material removal mechanisms, microstructure of the machined surface and related machining conditions were also investigated. Thermo-chemical polishing was proved to be able to remove the diamond film very effectively (4.8μm deep of diamond film was removed in 30 minutes when polishing at 550oC and 5.7m/s). The material removal rate was increased with polishing speed and pressure. Higher polishing temperature would improve the chemical reaction and result in better surface finish.
195
Authors: Takeshi Tanaka
Abstract: In this study, we proposed ER fluid-aided polisher (ERAP) using one-sided, patterned electrodes. The characteristics of ER fluid and ER fluid containing abrasive grit were investigated. The polishing performances of ER fluid containing abrasive grit were verified using an ERAP. The following conclusions were obtained. Thick clusters formed between both electrodes with increased voltage. Abrasive grit was condensed on the thick clusters of ER fluid-particles that formed around the electrodes with further increases in voltage. The ER effect is a hardening of ER fluid under loading by an electric field. The ER effect of ER fluid containing abrasive grit decreased because the grit clusters bound weakly to each other. The ER effect decreased with a decrease of grit size. The surface roughness showed little change when a Shower curtain (a nylon cloth) was used for a pad. An electric field was generated around the cutting zone when a Toraysee (a washable lens cloth) was used as a pad. This leads to large efficiency and high precision in polishing. The surface roughness decreased with increased voltage up to 1.0kV/mm, because the abrasive grit was tightly fixed by the ER effect. A minimum surface roughness was attained at approximately 1.0 kV/mm when using WA and SD grits. The surface roughness increased due to a hardening of the ER fluid, causing deep scratching of the workpiece at 2.0kV/mm.
201
Authors: Shao Hui Yin, Takeo Shinmura
207
Authors: Tsuyoshi Kaku, Nobuhito Yoshihara, Ji Wang Yan, Tsunemoto Kuriyagawa, Kazuhiko Abiko, Yoshiharu Mikami, Masahiro Noguchi
Abstract: The viscosity of an electrorheological fluid (ER fluid) increases with an increase in the intensity of an electric field. In the case of ER fluid-assisted micro polishing the workpiece needs to be a conductive material such as tungsten carbide and the gap between the workpiece and the polishing tool, which both act as electrodes, must be the same size as the abrasive grain. It is difficult to maintain a small gap when polishing the surface of the workpiece. In order to prevent direct contact between the workpiece and the polishing tool, a resin-coated polishing tool has been developed. In this paper, a micro polishing tool was made using a plasma chemical vapor deposition method. The geometry of the polishing tool was examined by a finite element method (FEM) to optimize the concentration of the abrasive grains. In polishing machining using the tool, the width of the polishing groove was 35 μm, and polishing machining in a micro area was achieved.
213
Authors: Zhong Ning Guo, X.Z. Huang, Zhi Gang Huang, Z.Q. Yu, T.M. Yue, Wing Bun Lee
Abstract: Experiment research of polishing based on liquid two-dimension vibration is carried out by a vibrating device which is driven by ultrasonic source and can produce coupling vibrations of liquid. Sound pressures of some key points in water are tested by hydrophone and translated into sound intensity to evaluate the effect of input voltage of transducer. It is analyzed which vibration state of fluid field and the way that workpiece is clamped is the best for the polishing. Polishing results of quartz glass are evaluated by the use of region-track measure method, and some polishing rules are presented.
219
Authors: Ke Wang, Ren Ke Kang, Zhu Ji Jin, Ning Hui Wang
Abstract: In order to obtain ultra-smooth and damage free substrate surfaces for MgO single-crystal substrate with high polishing efficiency, an experimental investigation based on systemically designed polishing experiments are presented and discussed. Considering the structural characteristics and chemical properties of the MgO single crystal, the experiments use a polishing slurry containing SiO2 abrasives so that the process is performed under a combination of mechanical and chemical actions. The effects of the polishing process parameters, such as polishing pressure, rotational speed of polishing plate, and the flow rate and concentration of the polishing slurry, on the surface roughness and material removal rate (MRR) are analyzed. Finally, a recommendation is made for selecting the appropriate polishing parameters for MgO single crystal substrate, based on which a surface roughness of 0.3nm can be achieved on the MgO substrate in 20min of polishing time.
225
Authors: Pai Shan Pa
Abstract: This study discusses electrochemical finishing of female screw using different types of completely inserted electrodes as well as feeding electrodes for die material. In the experiment, four types of design electrode are completely inserted and put through both continuous and pulse direct current and another four types of electrode are used with the application of continuous direct current and axial electrode feed. The controlled factors include the chemical composition and the concentration of the electrolyte, the electrolyte temperature, the flow rate of electrolyte, rotational speed of the electrode, current density, and current rating. The parameters are electrolytic time, die material, pulse period, feed rate of the electrode, and electrode geometry. For inserted electrodes, an electrode with thin plate provides more sufficient discharge space, which is advantageous for polishing. The electrode of single plate performs better than the double plate. Pulse direct current can promote the effect of electrochemical finishing, but the machining time is longer and the cost is raised. For feeding electrodes, an electrode of one side borer tip and thinner heavy section performs the best polishing effect in the current investigation. The electrochemical finishing after screw cutting just needs quite short time to make the surface of female screw smoothing and bright.
231
Authors: S.L. Ko, Yuri M. Baron, Jung Il Park
Abstract: Several types of inductors with permanent magnets for deburring using the MAF process were investigated in this paper. The magnetic intensity of each system was measured at working gap to determine the proper system. Using the inductor with a permanent magnet, which was designed and manufactured as a result of the investigation, the heterogeneity of the finishing process and the variations in the location of the magnet poles and the amount of the powder were analyzed during the deburring process. The characteristic curve was calculated from the experimental data and used to compare the performance of each inductor. Under similar conditions, the permanent magnet inductor showed superior performance compared to the electromagnetic inductor in the deburring process.
237
Authors: Yan Hua Zou, Takeo Shinmura
Abstract: A new magnetic deburring method for a drilled hole on the inside of tubing is proposed in this study. This internal deburring method applies the magnetic field assisted machining process by using a magnetic machining jig (permanent magnet tool). In this research, we examined experimentally the deburring of a drilled hole on the inside of SUS304 stainless steel tubing. A processing unit and magnetic machining jig were made, and the processing unit was set on a lathe machine. The deburring experiment was performed for a drill hole 3 mm in diameter. The results showed that the internal burr could be removed using this magnetic deburring process and the height of the burr could be successfully decreased from 163 μm to 1 μm. Thus, it was proved that this magnetic deburring method was effective for the internal deburring of long tubing.
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