Papers by Keyword: Internal Grinding

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Authors: Jian Sun, Peng Zhou, Yu Hou Wu, Ke Zhang, Li Xiu Zhang
Abstract: Different grinding parameters of silicon nitride ceramic are researched at the process of internal grinding. The influences on the roughness of surface by the linear speed of grinding wheel (vs), radial feeding speed (f) and axial vibration speed (fa) are studied in the uniformity testing. The experimental equation of silicon nitride ceramic internal grinding is optimized. The machined surface morphologies of the ceramic specimen are measured by roughness instrument of Taylor-Hobson Surtroni-25 and scanning electron microscope of S-4800. The results show that with the increasing of the linear speed of grinding wheel the roughness of surface get reduced, and with the increasing of radial feeding speed the roughness of surface get raised. It is also inversely proportional to the axial vibration speed. The linear speed of grinding wheel has the biggest impact on the roughness of surface of the silicon nitride ceramic internal grinding among the three grinding parameters. With the increasing of linear speed of grinding wheel, the value of roughness of surface declines from 0.4095μm to 0.1726μm. The influences on the roughness of surface of the silicon nitride ceramic internal grinding by different factors are found out in the research, and its removal mechanisms are cleared up under different linear speeds of grinding wheel.
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Authors: Ou Xie, Hua Li, Zheng Li, Zhen Yin
Abstract: A design solution of machine tool control system and its hardware and software design were proposed for the requirement of high precision internal grinding. The ARM microprocessor was used as the system control center and the technical grade touch screen was used as the human machine interface. The feed motion of the X, Z 2-axis servo motor was controlled by the system to complete the grinding path, and the machine tool switching signal was controlled by the Soft PLC Technology. The whole system has the advantage of stable, high performance and user friendly, meeting the requirement of high precision grinding.
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Authors: Y.G. Zheng, W.G. Liu, Bin Jiang, Hang Gao, S.G. Zheng
Abstract: According to the demand for internal grinding machine in precise machining of air-conditioner compressor piston hole, a kind of high precise CNC internal grinding machine with CBN wheel is developed by adopting self-adaptive control for grinding process. Meanwhile, grinding precision and stability are achieved by overcoming many problems emerging from high-speed grinding process with CBN wheel. More than 100000 times’ grinding experimental results show that the whole performance of grinding machine developed is the same as that of the same kind of international machine. In order to study grinding mechanism with CBN wheels and then improve machine’s capability, grinding data in several machining cycles is analyzed.
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Authors: Mitsuyoshi Nomura, Yong Bo Wu, Tsunemoto Kuriyagawa, Takahiro Kawashima, Takayuki Shibata
Abstract: This study aims to develop an ultrasonically assisted grinding technology for precision internal grinding of a small hole measuring several millimeters in diameter, such as those formed in a fuel injector for an automotive engine. In a previous work, an experimental apparatus mainly composed of an ultrasonic vibration spindle was designed and constructed, and grinding experiments were carried out. The purpose of this paper is to examine the effect of ultrasonic vibration on grinding force and surface roughness when the grain size and concentration of small cBN grinding wheel are changed. The experimental results indicate that applying ultrasonic vibration to the wheel decreases the normal and tangential grinding forces by more than 50% and 78%, respectively, and improves the surface roughness by as much as 10% when the wheel grain size and concentration are changed. In addition, over the range of grinding conditions employed in this paper, the grain size as small as 5μm can be used in ultrasonically assisted grinding.
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Authors: Mitsuyoshi Nomura, Yong Bo Wu, M. Kato, Tsunemoto Kuriyagawa
Abstract: This paper describes an experimental investigation of the effects of ultrasonic vibration in the truing and dressing of the small CBN grinding wheel used for the internal ultrasonic grinding of small holes. In the precision machining of small holes measuring several millimeters in diameter, improvement in the wheel truing accuracy is significantly levels off when using a single diamond dresser or a rotary GC wheel dresser. In the present work, a new truing and dressing technique was proposed, by which the grinding wheel is ultrasonically vibrated in its axial direction during the truing operation using a rotary GC cup dresser. In order to validate the proposed new technique, experiments were carried out. During experimental operations, the GC cup wheel was traversed along the vitrified CBN grinding wheel axis with an in-feed motion toward the grinding wheel in the wheel radial direction. The influences of the truing parameters on the truing force, the run-out of grinding wheel and the grinding wheel surface properties were investigated. As a result, it was found that applying ultrasonic vibration to the grinding wheel decreased the truing force by more than 22%, and the run-out of grinding wheel decreased from an original value of 150µm to a final one of less than 0.8µm, while that obtained without ultrasonic vibration was more than 1.1µm. As well, better surface properties of the grinding wheel were obtained by the application of ultrasonic vibration.
183
Authors: Ke Zhang, Jian Sun, He Wang, Yu Hou Wu
Abstract: Grinding is a main method of silicon nitride ceramic in finish machining stage. The technical parameters had an important influence on the surface quality of silicon nitride ceramic. The silicon nitride ceramic spindle was ground by the high-speed cylindrical grinder MGKS1432-H. The relations between different speed parameters and surface roughness were researched. The cylindrical and internal high speed grinding experiments of silicon nitride ceramics spindle were carried out. The S-4800 scanning electron microscope was used to explore the roughness change rule of the grinded surface under the condition of only changed grinding wheel’s velocity. In the process of cylindrical and internal grinding on silicon nitride ceramic spindle, the roughness tended to decrease with the linear velocity increasing, and increased with the radial feed speed increasing and decreased with the wheel shaft’s oscillation speed increasing. The result indicated that the linear velocity of grinding wheel influenced the sample’s roughness most. The effect of radial feed speed on the roughness is next only to the effect from linear velocity. The effect of shaft’s oscillation speed on the roughness is the lowest of the three factors. In the process of internal grinding, with the linear velocity increasing, the ceramic material transformed from brittle rupture to plastic deformation and the roughness appeared one peak. These results were very helpful to optimize the grinding parameters and improve grinding efficiency.
253
Authors: Yong Bo Wu, Xu Yue Wang, T. Tachibana, M. Kato
Abstract: This paper aims at the development of an alterative technique for truing and dressing a small vitrified CBN grinding wheel used for the internal finishing of small holes measuring several millimeters in diameter. In conventional truing and dressing, a single-tip diamond dresser or a rotary GC cup wheel dresser is employed. This levels off the improvement in the wheel truing accuracy because the stiffness of the grinding wheel shaft with an open-sided structure is low, and the shaft is thus deformed easily due to the truing force. In the present work, a new truing and dressing technique is proposed in which a Nd:YAG laser beam is employed as the dresser. Experiments were carried out with respect to the effects of the laser beam conditions (amplitude, width and frequency of pulse, and focus offset) and the relative motion between the laser beam and CBN wheel. It was found that the run-out of the CBN wheel was decreased significantly, and the wheel surface condition was improved greatly after laser truing and dressing.
163
Authors: Yasushi Mochida, Akihiko Kubo, Jun’ichi Tamaki, Katsuko Harano, Hitoshi Sumiya, A.M.M. Sharif Ullah
Abstract: A cutting-tool-type single-point diamond dresser, the tip of which has a given rake angle, was developed and its dressing and grinding performances were investigated. It was found that the dressing mechanism changes its mode from a ductile mode to a brittle mode with increasing back rake angle in the negative direction and that the cutting-tool-type dresser exhibits good robustness owing to the fact that its ground surface roughness is not markedly affected by the dressing conditions.
205
Authors: Hua Li, Z.W. Zhang, Zhen Yin
Abstract: In this paper, the background of ultrasonic vibration internal grinding (UIG) technology was described; the main parameters of the UIG technology were summarized. The recent development of the UIG mechanism, system and ultrasonic vibration internal honing technology was overviewed. The development trend and future prospect of the UIG technology were proposed based on above analysis.
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