• International journal of advanced smart convergence
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• v.5 no.4
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• pp.66-70
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• 2016

When tooth grinding occurs, electrical stimulation is given at the same time, and tooth grinding stops on such stimulation. Electromyography signals are used as control signals of electrical stimulation to disturb tooth grinding. However because of the electrical stimulation, the M-waves are generated and mixed with spontaneous electromyogram. In this study, we designed an optimal filter to remove M-wave and conserve spontaneous electromyogram simultaneously. The inverse power method (IPM) showed that the optimal filter coefficient is the eigenvector corresponding to the minimum eigenvalue of the input covariance matrix. In order to evaluate the performance of the optimal filter, we compared using a conventional band pass filter and adaptive filter using least mean square algorithm. The experimental results show that the optimal filter can effectively remove the M-wave compared to the previously studied prediction error filter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.7-12
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• 2013

This paper proposed the optimal algorithm of grinding system and the method to realize it. The optimal function was proposed in order to design the optimal grinding process. DE(Differential Evolution) algorithm was used to obtain the selective optimal function. The realization of algorithm was implemented by LabView software used widely at industrial field and the proposed algorithm was verified for through computer simulation. The result of the proposed algorithm can be used for the guide line of the grinding process.

• Journal of Soil and Groundwater Environment
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• v.23 no.1
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• pp.25-29
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• 2018

The effect of soil grinding on total As and Pb concentrations determined by aqua regia method was examined. Among six field-collected, air-dried soil samples tested, soils A, B, C, and E were directly sieved through a $150-{\mu}m$ sieve without grinding and showed 2.18 to 3.03 times higher total As concentrations and 2.62 to 3.45 times higher total Pb concentrations than those of the soil samples prepared to allow all soil particles to pass through the $150-{\mu}m$ sieve by grinding. The reason can be ascribed to the fact that those soils contain fine particles (i.e., < $150{\mu}m$ in diameter) only 4.6 to 6.8% of the total soil weights. On the other hand, for D and F soils, fine particles smaller than $150{\mu}m$ accounted for 57 and 46%, respectively, so that the effect of grinding on As and Pb concentrations were relatively low (As: 1.15 and 1.23 times, Pb: 1.36 and 1.49 times, respectively). The result demonstrates that grinding prior to $150-{\mu}m$ sieving is necessary to ensure the homogeneity of soil samples and hence to obtain more accurate heavy metal concentrations in soils. This is especially true for soil samples with less fine soil particles and/or microaggregates (i.e., below $150{\mu}m$).

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.246-251
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• 2000

In this paper, Wire electric discharge grinding(WEDG) method for manufacturing the micro shaft was introduced and the machining characteristics was investigated. from the experimental results, it was concluded that high surface integrity could be obtained by use of dielectric fluid spraying method and small capacitive condenser.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.142-148
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• 1993

Recectly, development of expert system utilizing the domain specific knowledge focuses upon the machining operations. This paper describes an expert system for selecting the optimum grinding wheel based on the Analytic Hierarchy Process and Fuzzy Logic. Knowledge-base, in this system, for selecting of grinding wheel is designed to appling the knowhow and experience knowledge of skilled hands. In this paper, firstly determination method of fuzzy membership function utilizing the qualitative knowledge, and then selection of the optimum wheel from among the available components according to Saaty's priority rule are described. Lastly,some implementation results are suggested.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.629-632
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• 2005

ELID(ELectrolytic In-process Dressing) grinding is an excellent technique for mirror grinding of various advanced metallic or nonmetallic materials. A polishing process is also required for elimination of scratches present on ELID grinded surfaces. MAP(Magnetic Assisted Polishing) has been used as a polishing method due to its high polishing efficiency and to its resulting in a superior surface quality. This study describes an effective fabrication method combining ELID and MAP of nano-precision mirror grinding for glass-lens molding mould, such as WC-Co, which are extensively used in precision tooling material. And for the optics glass-ceramic named Zerodure, which is extensively used in precision optics components too. The experimental results show that the combined method is very effective in reducing the time required for final polishing. The best surface roughness of the polished glass-ceramic was within 1.7nm Ra in this study.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.72-77
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• 2005

The materials used in a ship screw propeller are commonly made with brass. The seawater corrosion and seawater cavitation of the screw propeller reduces the propulsive performance of the ship. In screw manufacturing, the corrosion rust of the screw propeller is removed through a hand grinding method. The grinding process produces dust of the heavy metals from the brass. The dust creates a poor working environment that is harmful to the health of the workers. An automatic corrosionrust removing apparatus, using a blasting method, was developed for the improvement of screw polishing conditions and its working environment. The performance of this apparatus was investigated by surface roughness, weight loss rate, hardness, electrochemical corrosion resistance, and cavitation erosion, after removing of the corrosion rust under various blasting conditions. Two medias of alumina and emery were used in this experiment. The surface roughness and hardness of the screw were improved by this apparatus. The electrochemical corrosion potential (Ecorr) and current density (Icorr) were measured by the dynamic polarization method, using a potentiostat,under the conditions of surface polishing with grinding, blasting, wire brushing, and fine sand papering. The test results prove that the new corrosion rust-removing apparatus improves the surface performance of a screw propeller.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.8
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• pp.8-14
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• 2020

In the air current pulverizing type grinding method, the blade wings fitted inside a casing are rotated at a high speed to generate a cornering air current, which facilitates the collision of materials with one another, leading to the pulverizing phenomenon. In contrast to mechanical grinding, grit pulverizing leads to fine grinding and less acid waste and degeneration of the material. Moreover, this approach prevents the loss of nutritional value, while allowing the milling grain to have an excellent texture. However, the existing air current pulverizing type machines consist of prefabricated blades, which cannot be rotated at a speed higher than 5,000 rpm. Consequently, the grinding process becomes time consuming with a low productivity. To overcome these problems, in this study, the shape and structure of the air current pulverizing type wings were optimized to allow rapid grinding at more than 8,000 rpm. Moreover, the optimal design for the ripening parts for the air current pulverizing type device was determined by performing a computational fluid dynamics analysis based on airflow analyses to produce machinery that can grinding materials to the order of micrometers.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.4
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• pp.8-15
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• 2016

Most machines lose a lot of energy due to friction. Wear due to friction also reduces performance. Therefore, it is important to reduce friction on the surface to improve energy efficiency and decrease wear. Surface texturing refers to making patterns on the surface for reducing friction. There are many surface texturing methods, such as using lasers, abrasive jet machining, and so on. Recently, mechanical manufacturing methods, such as cutting and grinding, have been highlighted. Among them, the grinding method has the advantage of making patterns in large areas quickly. Therefore, it is appropriate for surface texturing on large machines. This paper is a study on the slope change of the surface texturing pattern using grinding. Therefore, we researched the slopes of the patterns corresponding to "spindle speed and feed rate" and "curvature of workpiece surface" using a mathematical model and experiment. As a result, we made a proper mathematical model concerning our research. Therefore, using the mathematical model in this paper, we could predict the slope change of the pattern according to grinding conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.24-27
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• 2002

The environmental problems by using coolant demanded the new cooling methods. As one of them, the studies on the finding with compressed cold air and oil mist have been done. The cooling method using compressed cold air was effective through going down the temperature of compressed air supplied below $-25^{\circ}$ and increasing the amount of compressed cold air, but had not enough cooling effect due to the low performance of lubrication. Therefore, the cooling methods using oil mist newly were suggested. This method can satisfy both cooling effect and lubrication with only small amount of coolant, also have the benefit in the point of decreasing the environmental pollution. This paper focused on analyzing the grinding characteristics of the cooling method using oil mist. The grinding test according to compressed cold air, oil mist spray pressure and oil mist supply direction were done.