• 한국표면공학회지
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• 제46권1호
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• pp.22-28
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• 2013

$WS_2$ particles were added to micro-diamond blades with Cu/Sn binding metal as lubricants to improve cutting efficiency. It was found in previous works that the added $WS_2$ lubricant could reduce remarkably the momentary energy consumption during dicing tests but increased wear rate slightly owing to weak bonding between lubricant particles and bond metals. In the present work, the surface of $WS_2$ lubricant particles were etched for activating the surface of $WS_2$ particles that provide even distribution of particles during powder mixing process and improvement of wetting at the interfaces between $WS_2$ particles and molten Cu/Sn bond metals during pressurized sintering so that could provide the improved strength of micro-blades and result in extended life. Chipping behavior of workpiece with the types of micro-blades including $WS_2$ were compared because it is important in semiconductor and micro-packaging industries to control average roughness and straightness of sliced surface which is closely related with quality.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권2호
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• pp.199-208
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• 2017

We perform an experiment on lacquer formation with simple test device. The anti-lacquer is one of important issues to increase durability, and to improve performance in the engines because the lacquer formation cause sticking of fuel injection pump, scuffing of cylinder liners, and increase of lubricant oil consumption in the marine diesel engines. We suggest this simple test in order to save enormous experimental cost in marine diesel engines, and in order to have ease in performing the various tests. The influences of the Base Number (BN) of lubricant oils and the sulfur content of fuel oils in the formation of lacquer are investigated. In order to investigate physical and chemical properties of lacquer, we perform a variety of tests such as, visual inspection, EDS. In addition, we investigate adhesion of lacquer by pull-off test quantitatively, and perform dissolution test with dilute sulfuric acid.

• 한국기계가공학회지
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• 제13권4호
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• pp.56-68
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• 2014

This paper presents an experiment on the modeling, analysis, prediction and optimization of machining parameters used during the turning process of the low-carbon steel known as ST40. The parameters used to develop the model are the cutting speed, the feed rate, and the depth of the cut. The experiments were carried out under various conditions, with three level of parameters and two different treatments for each level (with and without a lubricant), to determine the effects of the parameters on the surface roughness and electric current consumption. These effects were investigated using response surface methodology (RSM). A second-order model is used to predict the values of the surface roughness and the electric current consumption from the results of experiments which collected preliminary data. The results of the experiment and the predictions of the surface roughness and electric current consumption under both treatments were found to be nearly identical. This result shows that the feed rate is the main factor that influences the surface roughness and electric current consumption.

• 한국도로학회논문집
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• 제12권1호
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• pp.55-59
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• 2010

높은 차량운행비용(VOC : Vehicle Operating Cost)은 포장도로 복구작업의 주요한 원인이고, 차량운행비용(VOC)은 연료소모량, 오일소모량, 부품교체비용 등으로 구성된다. 이중 연료소모량이 VOC에서 차지하는 비중이 높고, 다른 도로조건에 비해 도로 표면 거칠기가 도로의 노화 정도를 대표적으로 지시하는 값이기 때문에, 본 연구에서는 포장도로의 표면 거칠기(IRI : International Roughness Index) 변화에 따른 차량의 연료소모량 변화를 측정하였다. 차량의 연료분사 인젝터의 전압변화를 측정하여 연료소모량을 계산하였고, 속도는 GPS센서를 사용하여 측정하였다. 본 실험 결과를 이용하여 IRI 변화에 대한 연료소모량의 변화율을 계산할 수 있었다. 계산 결과, 40~100km/h 속도영역에서 중형 및 대형 승용차의 연료소모량(L/100km)은 3.5m/km 정도의 IRI 수준에서 IRI(m/lm) 증가율의 7배 정도로 증가하였고, 60km/h의 속도에서 가장 연비가 우수하였다.

• KSTLE International Journal
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• 제3권1호
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• pp.26-29
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• 2002

The International Lubricant Standardization and Approval Committee (ILSAC) GF-3 passenger car engine oil specification has been introduced commercially in July 2001. The new specification oil provides superior performance in terms of fuel economy, control of high temperature deposits, and oil consumption. These enhanced performances of GF-3 engine oil need high quality base oil as well as a better additive system. In this paper, the effect of base oil on various performances of ILSAC GF-3 engine oil was investigated. From the GF-3 sequence engine tests, Group III base oil shows better performance in fuel economy retention, oxidation and varnish control than combination of group III and group II or group III and group 1.

• 한국자동차공학회논문집
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• 제7권8호
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• pp.7-16
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• 1999

To maintain thereasonable temperature in the engines is very important to keep the steady combustion state of engine and to prevent increasing of oil consumption , deteriorating of lubricant, shortening of the life time of engine and decreasing of material strength. The method of energy balance for divided elements of radiator and engine-oil cooler is considered to analyse the performance of radiator and engine-oil cooler. The data obtained by engine test and vehicle cooling tunnel test are applied to program for calculation of radiator outlet temperature. As a result, data obtained by numerical analysis agree well with those by experiments. And thus, it is concluded that this simulation program is available in developing the cooling system for a new car.

• Toxicological Research
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• 제32권3호
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• pp.245-250
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• 2016

3-Methylpentane ($C_6H_{14}$, CAS No. 96-14-0), isomer of hexane, is a colorless liquid originating naturally from petroleum or natural gas liquids. 3-Methylpentane has been used as a solvent in organic synthesis, as a lubricant, and as a raw material for producing carbon black. There is limited information available on the inhalation toxicity of 3-methylpentane, and the aim of this study was to determine its subacute inhalation toxicity. According to OECD Test Guideline 412 (subacute inhalation toxicity: 28-day study), Sprague Dawley rats were exposed to 0, 284, 1,135, and 4,540 ppm of 3-methylpentane for 6 hr/day, 5 days/week for 4 weeks via whole-body inhalation. Mortality, clinical signs, body weights, food consumption, hematology, serum chemistry, organ weights, and gross and histopathological findings were compared between control and all exposure groups. No mortality or remarkable clinical signs were observed during the study. No gross or histopathological lesions, or adverse effects on body weight, food consumption, hematology, serum chemistry, and organ weights were observed in any male or female rats in all exposure groups, although some statistically significant changes were observed in food consumption, serum chemistry, and organ weights. In conclusion, the results of this study indicate that no observable adverse effect level (NOAEL) for 3-methylpentane above 4,540 ppm/6 hr/day, 5 days/week for rats.

• Design & Manufacturing
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• 제6권1호
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• pp.24-28
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• 2012

Friction and wear affect all processes involved in the extraction of materials and their conversion into finished products in the die applications such as drawing, extrusion etc. Originating phenomenon from the contact surface between the tool and workpiece, they are usually a hindrance to materials process operations which usually result in damaging the tools, increasing energy consumption, the contamination of processed material by wear particles and also some problems associated with technologies to control friction and wear. The most well established method to control friction and wear is by the application of lubricant such as fluorocarbon. Besides, a surface technique so-called surface modification can be applied to solve the tribology problems of the die applications for both the economical and ecological reasons. In this article, we applied DLC(diamond-like carbon) thin film on alumina ceramic for HT test using the PIID(plasma ion immersion deposition), 4 groups of test specimens were tested up to $200^{\circ}C$ which is a little higher than the normal working temperature of die application. Pin-on-disc tribo-tester was used to test the friction and surfaces were characterized by SEM and EDS and else, the morphology changes of DLC coatings were studied. The present work indicated that the DLC had a great potential to reduce the friction and wear in the alumina die application without lubricants.

• 한국전자통신학회논문지
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• 제5권4호
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• pp.435-442
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• 2010

자동차의 와이퍼 브레이드 성능은 자동차 안전성 확보에 크게 기여한다. 유리면에 접착된 먼지나 이물질 등을 제거하는 기능을 확보하기 위해 와이퍼 브레이드는 닦임성, 내구력, 내열 저온 내오존성 내화학성이 높아야 할 뿐만 아니라 소음이 적어야 한다. 이와 같이 와이퍼의 기능 개선을 위해서는 와이퍼의 성능을 평가하고 분석할 수 있는 시스템 장비가 필수적이다. 본 논문에서는 자동차의 와이퍼 누름압을 측정하는 시스템의 개발을 위해 누름압 센서에서 출력되는 신호를 받아 퍼스널 컴퓨터에 전달하는 아날로그 디지털 변환기를 설계하고자 한다. 설계한 ADC는 빠른 동작 속도를 얻으면서 전체 시스템의 면적 및 전력소모를 최적화하는 구조인 파이프라인 ADC이다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3026-3031
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• 2008

In conventional closed-loop crankcase ventilation systems, the lubrication oil had to be re-circulated to the intake manifold, in the form of oil mist mixed with the blow-by gas. This blow-by gas containing the engine lubricant oil affects on the engine problems and the exhaust emissions. A high-efficient oil separator is required to minimize consumption of engine oil and reduce harmful emissions. In the conventional oil separator of CI engines, it has good oil separation performance even though separator design is simple, due to lots of the blow-by gas. As the emission regulation becomes severe, the oil separator for SI engines is also required. But in SI engines, separator design should be optimized, due to small size of oil particles and little amount of blow-by gas. In this study, oil separation performance classified by diameter of oil mist in cylinder head cover internal model which has three cyclones and two baffle plates for SI engine is calculated with CFD methodology.