• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.27.2-27.2
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• 2009

Grinding characteristics for aluminium and carbon nanotubes (CNTs) powder during traditional and planetary ball milling investigated from the viewpoint of particle behaviour with the aimat developing CNT-dispersed samples ground based on powder metallurgy routes.In this work, a comparison between the pure aluminium and CNT input aluminium grinding was carried out to determine grinding time effect on size reduction.We observed that the use of the curly small-diameter multi-walled carbon nanotubes (MWCNTs) attributed to the beneficial role of the MWCNTs as grinding aids. It is suggested that careful choices of the sizes of CNTs and Al powders would allow fine-grinding of composite particles with uniformly distributed CNT reinforcements thereby ensuring improved properties of the final composites produced by low-temperature compacting.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.796-799
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• 2000

The concern of environmental problems by using coolant required the recycling technologies of used coolant and development of environmental-firiendly coolant Some methods have been developing. Those are the dry grinding with compressed cold air and grinding with misted coolant. The farmer is effective in the cooling effect, but has not the performance of lubrication. Otherwise, the latter can satisfy both of them and also decrease the environmental pollution. This paper tried to analyze the cooling effect and surface integral of coolant, compressed cold air, mist through measuring the temperature of grind point and grinding force. Especially, the grinding method with misted coolant according to parameters was done. So, the finding method with misted coolant proved to be effective as one of methods to decrease the environmental pollution.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.3
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• pp.24-44
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• 2007

Cylindrical grinding is one of the important metal cutting processes used extensively in the finishing operation of discrete components. The inherent high cutting temperature in grinding if not controlled may lead to rapid tool wear, which in turn will lead to dimensional inaccuracy. The very nature of the grinding mechanism in material removal impairs the grounded surfaces by inducing residual stress, micro cracks and other thermal damages at the machined surface. This paper is an attempt to review some of the surface integrity issues in cylindrical grinding taken up and reported by number of researchers over the years. This review may have been planned to be useful to the researchers and other professionals interested to work on grinding.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.5
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• pp.751-756
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• 2023

In this study, We investigated a fire case and performed an experiment to prevent fire from sparks that is generated during grinding operation. Before conduct the test, confirmed that the generating mechanism of fire-flakes in working grinder and the fire experiment was conducted using commonly tools, flammable materials in industrial field. in result, It could be measured scattering distance, temperature, ignition possibility by type of combustible materials. Based on the results of this study, We are expected to be used as basic data for fire prevention in grinding Industry.

• Food Engineering Progress
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• v.21 no.4
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• pp.391-402
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• 2017

The purpose of this study was to improve the nutrition and the permeability of functional plants by using cryogenic grinding technology. Barley sprouts, Curcuma longa L., Dendropanax morbifera LEV., Phellinus linteus were dried, ground and extracted in different temperature conditions. Powder size of barley sprouts and Curcuma longa L. were about $50{\mu}m$ and Dendropanax morbifera LEV. and Phellinus linteus were about $20{\mu}m$. Cryogenic ground of Barley sprouts preserved 18.27-124.65% of nutrients such as protein, ash, carbohydrate, beta carotene, minerals, vitamins. Cryogenic grinding powder of Curcuma longa L. show high nutrients retention rate of lipid and carbohydrate. Permeability was measured by Parallel Artificial Membrane Permeability Assay (PAMPA) to predict passive gastrointestinal absorption. Permeability of saponarin, which is marker compound of Barley sprouts, is 9.88 times higher in cryogenic grinding powder than ambient grinding powder. Curcumin permability is 3.1 times higher than ambient grinded powder. As a result, particle size, nutrition, protein digestion degree and permeability demonstrated a positive relationship with the decreasing grinding temperature for the powders. These results confirm that the cryogenic grinding method had good suitability to increase functionality of plants, since it could minimize the heat generated while processing and effectively reduce the particle size.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.918-921
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• 2001

In grinding process, the heat of $1200^{\circ}$~$1500^{\circ}$ on the grinding area between grinding wheel and workpiece is generated. It decreases the surface integrity of workpiece and causes the thermal damages such as the deformed layer, residual stress and grinding burn. Generally coolant is widely used for preventing the heat generation on the grinding area, but it deteriorates the working condition by polluting the atmosphere of workplace and in the end pollutes the environment. The grinding methods using the compressed cold air and mist are the cooling methods to substitute conventional coolant. They can decrease the environmental pollution through not using coolant any more or minimizing it. In this study, the cooling effects of grinding methods using the compressed cold air and mist have been investigated. The grinding system equipped with the water bathe and mist spray nozzle was developed. The energy partition to workpiece through measuring the temperature on the workpiece surface was calculated. The surface integrity of workpiece and thermal damage like the deformed layer were analyzed.

• Journal of the Semiconductor & Display Technology
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• v.10 no.3
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• pp.35-42
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• 2011

This paper describes the characteristics of high speed grinding and the influence of wheel surface speed V and a grindability of the grinding materials. The various fine ceramics pieces was ground by metal and vitrified bonded diamond wheel. The surface roughness of fine ceramics(Zirconia($ZrO_2$), Silicon Carbide(SiC), Silicon Nitride($Si_3N_4$), Alumina($Al_2O_3$)) decreases from $0.05{\mu}m(R_{max})$ to $0.025{\mu}m(R_{max})$ when the wheel speed at grinding point increases the wheel speed. Relation between the temperature at grinding point and surface roughness was linear. Abrasive jet machining(AJM), a specialized from of shot blasting, is considered one of the most helpful micro machining methods for hard and brittle materials such as glasses and ceramics by constant pressure grinding.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.793-797
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• 2000

The environmental problems by using coolant demanded the new cooling methods. As one of them the studies on the dry grinding with compressed cold air have been done. The cooling method using compressed cold air was effdve thmugh going down the temperature of compressed air supplied below $-25^{\circ}C$ and inneasing the amount of mmpresd cold air, but had not enough cooling effect due to the low performance of lubrication. Therefore, the cooling methods using MQL(Minimum Quantity Lubrication) or mist newly were suggested. These two methods can satisfy both cooling effect and lubrication with only small amount of coolant, also has the benefit in the point of decreasing the envimnmental pollution. This paper focused on analyzing the grindmg characteristics of the cooling method using mid. The generated heat and grinding force of the cooling method using mist were compared with them of coolant and compressed cold air. And them grinding test according to the temperature of compressed cold air, mist spray amount and mist supply direction were done.

• Electrical & Electronic Materials
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• v.7 no.4
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• pp.306-311
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• 1994

In this study, the influence of the powder sintering, the 2nd sinteiing and the grinding time on the Superconducting properties in the Bi(Pb)SiCaCuO Superconductor has been studied. From the analysis of SEM and XRD patterns, it was known that the sample prepared by the process of powder sintering has a porous microstructure with the critical temperature(Tc) below 77K, while the sample prepared by the 2nd sintering has a highly oriented microstructure with the Tc above 100K. The Critical Current Density(Jc) of the sample prepared by the 2nd sintering was better than the sample prepared by the process of powder sinteiing, but it's Jc, was low in practical use. Also, the effect of grinding time from 0[min] to 120[min] was investigated. As the grinding time is increased, the samples degraded from high-Tc phase to low-Tc phase and nonsuperconducting phases.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.11
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• pp.1121-1128
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• 2013

Ultrasonic grinding system is that the ultrasonic vibration by ultrasonic actuator is applied on conventional grinding system during grinding process. The Ultrasonic vibration with a frequency of over 20kHz can reduce grinding forces and increase surface quality, material removal rate (MRR) and grinding wheel life. In addition, ultrasonic vibration assisted grinding can be used for the materials that are difficult to cut. In this paper, methodology for ultrasonic tools is studied based on finite element method, and in turn the ultrasonic tools are designed and fabricated. It is found that the ultrasonic tool can vibrate with a frequency of 20kHz and amplitude of $25{\mu}m$. In order to verify the machining performance, the grinding experiment is performed on titanium alloy. By applying ultrasonic vibration, the grinding force and temperature are reduced and MRR is increased compared with the conventional grinding.