• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.206-210
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• 2000

금형 및 자동차 산업에 널리 사용되는 앤드밀 가공에서 종종 소비자가 요구하는 가공 정밀도를 충족시켜 주지 못하는 경우가 발생한다. 이것은 열 변형, 공구 마모, 공작 기계 자체의 오차, 공구 처짐 등 다양한 원인이 존재한다. 본 연구에서는 공구 처짐으로 발생되는 가공 오차를 줄임으로써 가공 정밀도를 향상하기 위한 시스템을 개발하고자 한다. 이를 위해 3차원 볼 앤드밀의 절삭력 모델을 개발하고 시뮬레이션한다. 또한, 상용 CAD 시스템의 형상 및 가공 정보를 이용함으로써 모델링에서부터 가공 경로 생성, 그리고 경로 보정이라는 과정을 일괄적으로 수행할 수 있도록 한다. 이를 통해 사용자는 가공 전 시뮬레이션을 통해 가공 오차를 줄일 수 있는 기회를 제공 받는다. 따라서, 실제 가공에서 보다 높은 가공 정밀도를 얻을 수 있을 것이다.

• Clean Technology
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• v.12 no.1
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• pp.1-9
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• 2006

Aqueous cleaning agents which are considered to be environmental-friendly and promising alternative ones among various industrial cleaning agents were evaluated in this words. In order to formulate aqueous cleaning agents, primary alcohol ethoxylates with 3, 5 and 7 moles of ethylene oxides among nonionic surfactants were selected as main surfactants. And anionic surfactants and alcohols were chosen as their cosurfactants. Builders such as NaOH, KOH, $Na_2CO_3$ and $NaHCO_3$ were also evaluated as additives for improvement of cleaning efficiency of aqueous cleaning agents. The experimental results of cleaning ability tests show that introduction of anionic surfactant TLS as cosurfactant in alcohol ethoxylate-based aqueous solution gives the best cleaning efficiency for removing mixed soil of cutting oil and grease. NaOH and $Na_2CO_3$ are also shown to play an important role for improvement of cleaning efficiency in a aqueous cleaning agent.

• Clean Technology
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• v.7 no.4
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• pp.225-242
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• 2001

Cleaning process is necessary for machining parts or manufacturing finished products in the industry. Most of domestic and foreign companies are now trying to adopt environment-friendly aqueous cleaning agents instead of CFC-113 and 1,1,1-TCE which are ozone-depleting substances. However, the aqueous cleaning system has a disadvantage due to its generation of lots of waste water since the system utilizes water in cleaning and rinsing processes. Thus, it is very important that monitoring and recycling technologies of the cleaning solution and the rinse water should be introduced in the aqueous cleaning system in order to minimize generation of waste water and to maintain its cleaning performance for a quite long time. In this paper, the cleaning agents utilized in the aqueous cleaning system and cutting oils which are main contaminants were examined and analyzed. And the monitoring and recycling technologies of the aqueous cleaning system which can be employed in the industrial fields were also reviewed and evaluated.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.7
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• pp.834-843
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• 2014

A two-stage electrostatic precipitator (ESP) using a carbon brush charger and a plate-plate parallel aluminum collector was developed and its application for removal of oil mist aerosols was investigated. Charge number per particle and particle collection efficiency at different applied voltage to the carbon brush charger were measured and compared to those obtained by theoretical calculations. A long-term operation of the ESP during 9 weeks was also performed to evaluate its performance durability for oil mists. Average charge number per mist particle increased with the applied voltage to the charger, and thus the collection efficiency of the mist particles also increased overall at the particle size range of 0.26 - 3 mm. The tendencies of the average charge number per particle and particle collection efficiency obtained from theoretical calculations were considerably consistent with those of the experimental results. Particle collection efficiency of ~99 % at 0.3 mm could be achieved by power consumption of only 0.0033 W/($m^3/h$) at the face velocity of 1 m/s and its collection performance maintained stably during every 8 hr operation per day for 9 weeks with little increase of pressure drop.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1493-1498
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• 2010

This paper present the characteristics of micro- and meso-scale milling processes in which compressed cold air, minimum quantity lubrication (MQL) and $MoS_2$ nanofluid MQL are used. For process characterization, the microand meso-scale milling experiments are conducted using desktop meso-scale machine tool system and the surface roughness is measured. The experimental results show that the use of compressed chilly air and nanofluid MQL in the micro- and meso-scale milling processes is effective in improving the surface finish.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.1
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• pp.52-60
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• 2005

This study was carried to assess the accuracy of material safety data sheets (MSDS) for some water-soluble metalworking fluid (MWF) with respect to mono- ethanolamine(MEA), di-ethanolamine(DEA) and tri-ethanolamine (TEA). 39 fresh and 52 used MWFs for this study were taken from the workplace. The quantification and qualification of MEA, DEA and TEA were done using ion-chromatography. Three main findings of this study were 1) EA that was not addressed in material safety & data sheets (MSDS) was found to be enough higher than 1%, 2) 33.3% of 39 fresh MWF showed ingredient and concentration of MEA, DEA and TEA in MSDS and 3) the concentrations of MEA(20.5%), DEA(41.3%) and TEA(15.4%) were much higher than those indicated in MSDS. Consequently, we concluded that the accuracy on ingredients and concentrations of MEA, DEA and TEA provided in MWF was very low. Our study recommends that the limit concentration of chemical except for carcinogen that employer has to indicate in MSDS should be lowered from 1% to 0.1% .

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.3
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• pp.270-276
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• 2005

This study was conducted to examine whether a specific synthetic metalworking fluid (MWF), "A", in use for 10 months without replacement, displayed microbial resistance and to identify the additives associated with the control of microbial growth. Three synthetic MWF products ("A", "B", and "C") were studied every week for two months. Microbial deterioration of the fluids was assessed through evaluation by endotoxin, bacteria and fungi levels in the MWFs. In addition, formaldehyde, boron, ethanolamine, and copper levels were also studied to determine whether they influence microbial growth in water-based MWFs. Throughout the entire study in the sump where MWF "A" was used, bacteria counts were lower than 103 CFU/mL, and endotoxins never exceeded 103 EU/mL. These levels were significantly lower than levels observed in sumps badly deteriorated with microbes. Boron levels in MWF "A" ranged from 91.7 to 129.6 ppm, which was significantly higher than boron levels found in other MWF products. The total level of ethanolamine (EA) in MWF "A" ranged from 35,595 to 57,857 ppm (average 40,903 ppm), which was over ten times higher than that found in other MWFs. Monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) concentrations in MWF "A" were also significantly higher than seen in other MWFs. However, although EA and boron might improve anti-microbial performance, their abuse can pose a serious risk to workers who handle MWFs. From an industrial hygiene perspective, our study results stress that the positive synergistic effect of boron and EA in reducing microbial activity in MWF must be balanced with the potentially negative health effects of such additives. Our study also addresses the disadvantage of failing to comprehensively report MWF additives on Material Safety Data Sheets (MSDS). Future research in MWF formulation is needed to find the best level of EA and boron for achieving optimal synergistic anti-microbial effects while minimizing employee health hazards.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.7
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• pp.665-671
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• 2010

To improve the gear noise quality, gear tooth grinding machine are widely used in automotive industry. While using the gear profile grinding machine to improve the gear tooth quality of the transmission, several defects such as chattering, tooth waves that cause the gear noise occasionally happened. But it is very difficult to solve that problem, because there is no one who knows the setting up the optimal grinding condition appropriately. The abnormal manufacturing conditions which make the gear noise make the engineer to spend a lot of time, effort, and money. Due to demands for solving the serious abnormal gear noise happened in the automatic transmission in the mass product stage, the vibration checking process in the worm wheel axis, work rotation and fixed axis of the grinding machine were adapted to find the root causes. As a result, gear profile wave are affected by the work rotation axis's unbalance which is caused by worm wheel feeding speed. And a primary and the secondary grinding feeding speed, cutting oil, work fixed forces are also proved as the important factors. After setting up the grinding condition reported in this paper, it was adapted successfully to the grinding machine to manufacture the new automatic transmissions' gear. The gear noise was dramatically disappeared and the process and the results will offer good guides to the engineers who manufacture the gear with the grinding machine.

• Journal of Korea Foundry Society
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• v.41 no.2
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• pp.139-143
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• 2021

A type of titanium alloy, ferro-titanium, is the main material used to manufacture steel and stainless steel. Considering economic aspects, ferro-titanium ingots are intended to be manufactured using low-cost titanium scrap, and the best pretreatment process for removing impurities from recycled titanium scrap surfaces was studied here. Instead of ordinary acid or organic solvents, ecofriendly methods were researched and applied, and chip scrap materials were used. A high-quality ferro-titanium ingot was manufactured from titanium scrap after a pretreatment process was applied, and the impurities and properties were analyzed and compared with commercial material standards through a component analysis.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.5
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• pp.98-104
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• 2022

When processing parts, the cutting oil can improve the cooling performance of the workpiece and tool to increase the precision of the workpiece or extend the life of the tool and facilitate chip extraction. Since such cutting oil has a harmful effect on the environment and the human body due to additives such as sulfur, research on a minimum lubrication supply method using an eco-friendly oil is recently underway. The minimum lubrication supply method minimizes the amount of cutting oil used during processing and processes it, which can reduce the amount of cutting oil used, but has a problem in that cooling performance efficiency is poor. Therefore, this study conducted a study on mist cooling of lubricants to reduce the amount of cutting oil used and maximize the cooling effect of processing heat generated during tapping processing. Spray pressure, processing speed, direction, and lubricant spray amount, which are considered to have an effect on cooling performance, were set as process conditions, and the effect on temperature was analyzed by performing an experiment using the box benquin method among experiments were analyzed. Through the experimental analysis results, the optimal conditions for mist and processing that maximize the cooling effect were derived, and the validity of the results derived through additional experiments was verified. In the case of processing by applying the mist lubrication method verified through this study, it is considered that high-precision processing is possible by improving the cooling effect.