• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.7 no.2
• /
• pp.100-107
• /
• 1998

Diamond wheels with fine grains and multi-porous structures are newely trial developed for smoothing and mirror finishing materials. Grinding wheel must have performed both to remove tool marks efficienitly and to contact elastically with curved surfaces, that are employed for ultra precision and high performance grinding of difficult-to materials such as tungsten carbide alloy using tool and die materials, Diamond grains are bonded by a melamine resin to prevent the decrease of machining efficiency due to grain sinking within the bond materials. Also, highly foamed structures are developed to increase the flexibility of the grinding wheel, and to induce self-sharpening by increasing contact pressure between the grinding wheel and workpiece surfaces. In this paper, melamine-bonded diamond wheels try to manufacture, then the forming method of grinding wheel are suggested, and the grinding characteristics of melamine-bonded diamond grinding wheel are also illustrated.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.04a
• /
• pp.447-452
• /
• 2000

The grinding plays a key role which decide the quality of a product finally. But the grinding process is very irregular, so it is very difficult to analyse the process accurately. Therefore it is very important in the aspect of precision and automation to reduce the idle time and to decide the proper dressing time by visualizing. In this study, we choose the direct method of observation by making use of computer vision, and apply pattern classification technique to the method of measuring the wheel surface. Pattern classification technique is proper to analyse complex surface image. We observe the change of the wheel surface by making use of the gray level run lengths which are representative prince in this technique.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.21 no.12
• /
• pp.2172-2178
• /
• 1997

Development of diamond wheel with fine grains and multi-pore structures were newely attempted. Wheels, that are employed for ultra precision and high performance grinding of difficult-to materials such as tungsten carbide alloy using tool and die materials, must have both performances to remove tool marks efficiently and to contact elastically with curved surfaces. Diamond grains were bonded firmly by a melamine resin to prevent the decrease of machining efficiency due to grain sinking within the bond materials. Also, highly foamed structures were developed to increase the flexibility of the wheel, and to induce active self-sharpening by increasing contact pressure between the wheel and work surfaces. In this paper, melamine-bonded diamond wheels are trial manufactured, then the forming method of wheels are suggested, and the grinding characteristics of wheels are also illustrated.

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.6
• /
• pp.45-51
• /
• 1996

Silicon wafers are required to be finished under the roughness of nanometer order for the subsequent chip fabrication processes. Recently, the finish grinding techniques have been researched for the improvement of accuracy and surface roughness simultaneously. Among them, the grinding technique using fine abrasive has been known as an easily accessible method. However, the manufacture of the fine grit grinding wheel has been very difficult because of the coherence of the grits. In this paper, the development of the ultrafine grit silica($SiO_2$) grinding wheel by the combination of the binder coating and the vacuum forming techniques is reported. And, the mechanochemical removal effects of the grinding conditions are discussed. Finally, a successful result of Ra O.4nm. Rmax 4nm in the ground surface roughness of a 6 inch silicon wafer was achieved.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.11
• /
• pp.132-137
• /
• 2001

Application of ceramics, carbide, ferrite has grown considerably due to their mechanical properties such as high degree hardness, chemical stability, super wear resistance. Despite these characters, the use of advanced material has not increased because of poor machinability. The application of metal bonded wheel was proposed. But it is difficult that metal bond wheel can be dressed. Recently, to solve this problem, the technology of in-process electrolytic dressing is developed. This method need wheel for electrolytic dressing, power supply and electrolyte. The aim of this study is development of CIB-D wheel for electrolytic and its evaluation of electrolytic characteristics, and achieve ultra-precision lapping of carbide, optic glass.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.2
• /
• pp.172-179
• /
• 2005

A high-precision centerless grinding machine has been recognized as a core equipment performing the finish outer-diameter grinding process of ferrules which are widely used as fiber optic connectors. In this study, in order to realize the high-precision centerless grinding machine, the structural characteristic analysis and evaluation are carried out on the virtual prototype consisted of the steel bed, hydrostatic GW and RW spindle systems, hydrostatic RW feed mechanism, RW swivel mechanism, and on-machine GW and RW dressers. The loop stiffnesses of centerless grinding machine are estimated based on the relative deformations between GW and RW caused by the grinding forces. And the simulated results illustrate that the concrete-filled bed has the considerable effect on the improvement of the structural stiffness of centerless grinding machine.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.7 no.5
• /
• pp.29-37
• /
• 1998

In recent years, grinding techniques for precision machining of stainless steel used in shaft, screw parts and clear value have been improved by using the superabrasive wheel and precision grinding machine. The completion of optimum dressing of superabrasive wheel makes possible the effective precision grinding of stainless steel. However, the present dressing system cannot have control of optimum dressing of the superabrasive wheel. In this study, a new system and the grinding mechanism of optimum in-process dressing of superabrasive wheel. Therefore, the optimum in-process electrolytic dressing is a good method to obtain the efficiency and mirror-like grinding of stainless steel (STS304)

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.18 no.5
• /
• pp.498-506
• /
• 2009

An experimental study was performed to select cutting parameters for better quality-products in hard metals such as steels. Usually, a hard metal can be cut with a rotary cutting knife and the process provides a good cutting quality result. However, the cutting machine is much sensitive in cutting conditions because of its complicated mechanism. By this reason, careful processing conditions must be taken to improve the quality of the products. This experimental study for better quality products with a rotary cutting knife was carried out with two main factors; cutting speeds and cutting and pooling forces. A two-dimensional profile measuring instrument is used to evaluate its cutting faces and the effects of processing factors are analyzed by a commercial software.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.9
• /
• pp.145-151
• /
• 1998

In this study, the experimental and analytic investigation with cold air system has been performed for improving the working environment of the conventional grinding fluid. Very simple cold air system was developed which could replace by the conventional grinding fluid system. The identification of heat of grinding Bone is very important for precision grinding. The experimental data was analysed to investigate the heat which was transferred to the workpiece. It was found that 45∼55％ of the total energy for dry grinding, 22∼28％ for wet grinding, and 32∼35％ for cold air system are conducted to the workpiece in grinding with cubic boron nitride wheel. Cubic boron nitride wheel could reduce the residual stress and thermal demage comparing with aluminium oxide wheel, because cubic boron nitride wheel has very high extreme thermal conductivity.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.952-955
• /
• 2002

$WC-3%(Cr_3C_2)-2%(Mo_2C)-12%Ni$ carbides were ground with three different types of electroplated diamond wheels with respect to grain friability. The grinding ratio in the case of the highest toughness grains, A becomes the highest at the workpiece speeds of 40 and 70mm/min exhibiting larger effect with smaller workpiece speed. The grinding ratio with the medium toughness grain is higher than that of grain A at higher workpiece speeds than 100mm/min. The surface roughness becomes smaller with increasing the grain friability The increasing rate on surface roughness with the increase of workpiece speed becomes higher with using the grain of lower friability.