• 한국정밀공학회지
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• 제32권8호
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• pp.693-698
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• 2015

Recently, the quality of products after the corresponding machining processes were scrutinized in the interest of maintaining a high product-quality standard. The structure and stability of machine tools are important for the prediction of product quality. A structural analysis needs to be carried out to achieve the stable design of machine tools before the initial design stage in the manufacturing process of a precision product. In this study, a structural analysis was carried out using a finite element analysis (FEA) simulation to obtain the design stability of the main parts of a grinding machine. The sizes and locations of both the maximum stress and deformation in consideration of the cutting force of the chuck, tail stock, and bearing of the grinding machine were analyzed. Finally the grinding machine was successfully developed.

• 한국정밀공학회지
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• 제3권2호
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• pp.55-61
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• 1986

The study is concerned with the investigation of grinding factor affecting the AE Source by means of the relation between the amplitude level of AE signal and the depth of wheel engagement in surface grinding by AE method. As the result, work velocity was confirmed that the amplitude of AE signal had almost constant value in comparison with the depth of wheel engagement. But the depth of wheel engagement and the width of wheel engagement were proportional to the amplitude of AE signal. Therefore, when the AE Source was classified by 3-zone, Ws and Wf were affected by the depth of wheel engagement and that Wr was affected by the width of wheel engagement. Also, the adaptability of the AE method was studied about the detection of tool life of grinding wheel, sparkout and initial contact point.

• 한국분말재료학회지
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• 제13권5호
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• pp.313-320
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• 2006

The present study is to analyze the thermoelectric properties of $Bi_{0.4}Sb_{1.6}Te_3$ thermoelectric materials fabricated by the mechanical grinding process. The $Bi_{0.4}Sb_{1.6}Te_3$ powders were prepared by the combination of mechanical milling and reduction treating methods using simply crushed pre-alloyed $Bi_{0.4}Sb_{1.6}Te_3$ powder. The mechanical milling was carried out using the tumbler-ball mill and planetary ball mill. The tumbler-ball milling had an effect on the carrier mobility rather than the carrier concentration, whereas, the latter on the carrier concentration. The specific electric resistivity and Seebeck coefficient decreased with increasing the reduction-heat-treatment time. The thermal conductivity continuously increased with increasing the reduction-heat-treatment time. The figure of merit of the $Bi_{0.4}Sb_{1.6}Te_3$ sintered body prepared by the mechanical grinding process showed higher value than one of the sintered body of the simply crushed powder.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.90-95
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• 2005

To perform the finish outside-diameter grinding process of ferrules which are widely used as fiber optic connectors, a high-precision centerless grinding machine is necessary. In this study, the thermal characteristics of the high-precision centerless grinding machine such as the temperature distribution, temperature rise and thermal deformation, are estimated based on the virtual prototype of the grinding machine and the heat generation rates of heat sources related to the machine operation conditions. The reliability of the predicted results is demonstrated by the temperature characteristics measured from the physical prototype. Especially, the predicted and measured results show the fact that the high-precision centerless grinding machine consisted of the hydrostatic GW and RW spindle systems, hydrostatic RW feeding mechanism, RW swivel mechanism, on-machine GW and RW dressers, and concrete-filled steel bed, has very stable thermal characteristics.

• 한국정밀공학회지
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• 제29권12호
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• pp.1267-1271
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• 2012

Demand for optical glass device used for lighting could increase rapidly because of LED lighting market growth. The optical glass devices that have been formed by hot press molding process the desired optical performance without being subjected to mechanical processing such as curve generation or grinding. EL-Max material has been used for many engineering applications because of their high wear resistance, high compressive strength, corrosion resistant and very good dimensional stability. EL-Max is very useful for a glass lens mold especially at high temperature and pressure. The performance and reliability of optical components are strongly influenced by the surface damage of EL-Max during grinding process. Therefore, the severe process condition optimization shall be necessary for the highly qualified EL-Max glass lens mold. To get the required qualified surface of EL-Max, the selection of type of the diamond wheel is also important. In this paper, we report best grinding conditions of ultra-precision grinding machining. The grinding machining results of the form accuracy and surface roughness have been analyzed by using Form Talysurf and NanoScan.

• Journal of the Korean Wood Science and Technology
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• 제40권3호
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• pp.156-163
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• 2012

본 연구에서는 국내산 리그노셀룰로오스 자원을 이용하여 기계적 처리를 통해 나노섬유를 제조 후, 형태학적 특성 및 고강도 시트로의 응용 가능성을 평가하였다. 그 결과, 연속식 분쇄 처리는 세포벽의 구조를 느슨하게하고 분쇄 소요 시간이 증가함에 따라 나노스케일에 가까운 섬유가 관찰되었다. 재료의 미립화 정도를 증명하는 여수시간은 모든 공시재료에서 분쇄 소요시간이 증가함에 따라 직선적인 증가 경향을 나타내었다. 셀룰로오스의 상대결정화는 기계적인 해섬처리 정도에 따른 차이를 보이지 않았으나 탈리그닌 처리에 의해 크게 증가하였다. 셀룰로오스 나노섬유 시트는 기계적인 분쇄 소요시간이 증가함에 따라 인장강도가 증가하였고 옥수수줄기를 이용한 시트에서 특히 높은 인장강도가 측정되었다. 상기와 같은 결과는 국내 자생 식물자원을 활용한 셀룰로오스 나노섬유 제조 기술의 유용한 기초자료로 활용될 수 있을 것으로 판단된다.

• 한국기계가공학회지
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• 제12권4호
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• pp.75-80
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• 2013

Single crystal sapphire being used in high technology industry is a brittle material with a high hardness and excellent physical properties. ELID(Electrolytic In-Process Dressing) grinding technology was applied to material removal machining process of single crystal sapphire wafer. Ultrasonic vibration which added to material using ultrasonic table was adopted to efficient ELID grinding of sapphire materials. The evaluation of the ground surface of single crystal sapphire wafer was carried out by means of surface measuring by using AFM(Atomic Force Microscope), surface roughness tester and optical microscope device. As the results of experiment, it was shown that more efficient grinding was conducted when using ultrasonic table. In case of using #170 grinding wheel, surface roughness of ELID ground specimen in using ultrasonic table was superior to ELID ground specimen without ultrasonic table. However, In case of using #2000 grinding wheel, surface roughness of ELID ground specimen in using ultrasonic table was inferior to ELID ground specimen without ultrasonic table.

• Design & Manufacturing
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• 제11권1호
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• pp.1-6
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• 2017

In these days, due to generalization of using smart mobile phone and wearable device such as smart watch, demand of Cover-glass and touch screen panel for protecting display increases. With increasing the demand of Cover-glass, slimming technique is promising for weight lightening, zero bezel. Cover-glass produced by this technique is required to decreasing thickness with increase strength. In the Cover-glass manufacturing process, mechanical processing and chemical processing has improve in the strength. Generally, Diamond electrodeposition wheel is used in mechanical process. Reinforced glass with the characteristics of the brittle and high hardness was manufactured by using a diamond electrodeposition wheel. At this time, Because of surface of the tool present non-uniform distribution of diamond particle, it has generate Loading of wheel and it has been decrease life of grinding tool, efficiency of grinding, quality and shape accuracy of workpiece. Thus Research is needed to controling particle distribution of diamond electrodeposition wheel uniformly. And it is necessary to study micro hole machining such as proximity senser hole, speaker hole positioned Cover-glass. Reinforced glass with the characteristics of the brittle and high hardness is difficult to machining. Processing of reinforced glass have generated wear of tool, micro cracks. Also, it is decreasing shape accuracy. In this paper, We conducted a study on how to control particle distribution uniformly about the diamond tool manufactured using elecetodeposition processing. It analyzed the factors that affect the arrangement of the particles in the electrodeposition process by design of experiment. And There is produced the grinding tool, which derives an optimum deposition conditions, for processing Cover-glass edge and the machinability was evaluated.

• International journal of advanced smart convergence
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• 제4권2호
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• pp.84-93
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• 2015

This study is for the development of Cover Glass Grinding Processing System. This system is developed for manufacturing a mass product system grinding cover glasses with highly precise mechanism, and we improved resulted quality. In the development process, we developed a complete process technology through mechanical design, image processing technology, spindle control, mark identification algorithm etc. With this cover glass grinding development, we could developed process technology, image processing technology, organization mechanisms and control algorithms.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.71-76
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• 2001

In general, it is known that the wear rate of the abrasive and the removal rate of the metal bond of the grinding wheel should be balanced to maintain the depth of the insulating surface layer to an appropriate level. In order to accomplish, the high quality ELID grinding, therefore, it is necessary to measure the depth of the insulating layer in real-time and then to control the electrolytic conditions to keep the depth to a certain level. In this study, an in-process measurement system of the insulated layer using two gap sensors - a capacitor type and an eddy current type - developed and the change of the status of the insulated layer during ELID grinding is detected. And from the experimental data, we have chosen the best mathematical model to predict the depth of the insulating layer.