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티타늄 가공에서 절삭력 분석을 위한 ADL 밀링 가공특성
한정식,정종윤,Han, Jeong Sik,Jung, Jong Yun 한국산업경영시스템학회 2022 한국산업경영시스템학회지 Vol.45 No.3
The purpose of using coolant in machining is both to increase a tool life and also to prevent product deformation and thus, stabilize the surface quality by lubricating and cooling the tool and the machining surface. However, a very small amount of cutting mist should be used because chlorine-based extreme pressure additives are used to generate environmental pollutants in the production process and cause occupational diseases of workers. In this study, medical titanium alloy (Ti-6Al-7Nb) was subjected to a processing experiment by selecting factors and levels affecting cutting power in the processing of the Aerosol Dry Lubrication (ADL) method using vegetable oil. The machining shape was a slot to sufficiently reflect the effect of the cutting depth. As for the measurement of cutting force, the trend of cutting characteristics was identified through complete factor analysis. The factors affecting the cutting force of ADL slot processing were identified using the reaction surface analysis method, and the characteristics of the cutting force according to the change in factor level were analyzed. As the cutting speed increased, the cutting force decreased and then increased again. The cutting force continued to increase as the feed speed increased. The increase in the cutting depth increased the cutting force more significantly than the increase in the cutting speed and the feed speed. Through the reaction surface analysis method, the regression equation for predicting cutting force was identified, and the optimal processing conditions were proposed. The cutting force was predicted from the secondary regression equation and compared with the experimental value.
한정식(Jeong-sik Han),정병훈(Byoung-hun Jeong),김영운(Young-wun Kim),홍진숙(Jinsook Hong),정근우(Keunwoo Chung) 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.12
고무탄성체가 연료와 접촉하면 저분자량의 고무성분이나 첨가제 등이 연료에 의해 용출되면서 고무의 기계적 물성을 저하시키고 연료의 물성에도 영향을 미치게 된다. 본 연구에서는 고무탄성체 중 밀봉재로 사용되는 고무 오링이 연료와 접촉하고 있을 때 온도에 따라 고무 오링의 기계적 물성치중 영구압축줄음율을 측정하여 변화정도를 추적하고 이를 근거로 고무 오링의 수명을 예측하였다. 고무의 수명예측은 가속열화 시험에 의한 아레니우스 식을 이용하였으며 예측된 수명은 유제의 종류에 따라 20 ℃에서 16년 ~ 394년의 수명을 갖는 것으로 나타났다. When rubber elastomers have contact with fuel, because rubber component and its additive having low molecular weight can flow out, the physical properties of the elastomer and fuel are influenced. This study is about pursuing and measuring the change of compression set, as one of mechanical properties on temperature for sealant rubber O-ring contacted with fuel. We also could predict the life of the rubber elastomers. The life assessment of 16 to 394 years at 20 ℃ by the kinds of fuel could be calculated based on Arrhenius Equation using accelerated degradation test
한정식(Jeong-Sik Han),정종윤(Jeong-Sik Han),문덕희(Dug-Hee Moon) 한국산업경영시스템학회 2008 한국산업경영시스템학회지 Vol.31 No.2
Surface roughness is an important factor to evaluate machined parts in precision machining. This is the major measure of surface quality. This research sets up experiments to select the factors which affect surface roughness in the machining of inclined planes of aluminum. The levels of the selected experimental factors are chosen to evaluate the relationship between the surface roughness of the machined parts and machining parameters. This is to find out the optimal machining condition in the inclined planes. The objective of this research is to improve the surface roughness of the machined products by using the ANOVA analysis. The factors for the experiments are cutting speed, feed rate, cutting depth, and cutting width. The experimental levels of the factors are two for the cutting depth and width. For the cutting speed and feed rate, their levels are three because they are more sensitive for the surface roughness than the other two. The inclined planes are machined by 5-axis machining equipment.
광학 활성 2-Amino-3-Phosphonopropionic Acid의 새로운 합성 방법과 그를 포함하는 펩티드의 합성
김상범,조성기,한정식,김용준,홍석인,Kim Sang Bum,Cho Sung Ki,Han Jeong Sik,Kim Yong Joon,Hong Suk-In 대한화학회 1994 대한화학회지 Vol.38 No.7
L-serine으로부터 광학 활성을 가지는 2-amino-3-phosphonopropionic acid를 새로운 방법으로 합성하였으며 2-amino-3-(diethylphosphono)-propionic acid methyl ester를 아미노산과 축합시켜 광학 활성을 갖는 새로운 포스포노트리펩티드를 합성하였다. New synthetic method of optically active 2-amino-3-phosphonopropionic acid from L-serine was developed and their phosphonotripeptides, phthalylglycylglycyl-2-amino-3-(diethylphosphono)-propionic acid methyl ester and phthalylglycyl-L-phenylalanyl-2-amino-3-(diethylphosphono)propionic acid methyl ester, were synthesized by coupling reaction of amino acids with 2-amino-3-phosphonopropionic acid methyl ester.
정병훈 ( Byung Hun Jeong ),한정식 ( Jeong Sik Han ),이정호 ( Jeong Ho Lee ),김성보 ( Seong Bo Kim ),이범재 ( Bum Jae Lee ) 한국화학공학회 2005 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.43 No.5
이중고리형 불포화탄화수소 화합물인 methylcyclopentadiene dimer(MCPD)의 수소화 및 이성화반응에 관한 연구를 행하였다. Exo 화합물은 2단계의 수소화반응 후에 이성화반응에 의해 제조되었다. 수소 1몰이 첨가되는 1차 수소화 반응은 100˚C이상의 반응온도에서는 다이머가 분해되어 모노머가 생성이 증가되었다. 1차 수소화 반응에 의하여 DHDMCPD[dihydrodi(methylcyclopentadiene)]가 생성된 후 2차 수소화반응을 진행하여 THDMCPD[tetrahydrodi (methylcyclopentadiene)]를 제조하였는데, 2차 반응온도조절에 의해 exo와 endo 비율이 변화되었다. 공정개선을 위하여 2단 가열반응기를 사용함으로 연속식 1, 2차 수소화 조건을 확립하였고 또한 endo THDMCPD로부터 exo 형태로의 이성화반응에 할로겐화 알루미늄과 같은 할로겐화 금속촉매와 고체산 촉매를 사용하여 촉매의 활성을 비교하였다. The study on the hydrogenation and isomerization of unsaturated bicyclic hydrcarbon compounds using methylcyclopentadiene dimer (MCPD) was carried out. Exo compound was prepared through isomerization reaction after two hydrogenation reaction steps. In the first hydrogenation reaction which needs one mole of hydrogen, the formation rate of monomer was increased as dimer was decomposed at reaction temperature above 100oC. At first hydrogenation, DHDMCPD [dihydrodi (methylcyclopentadiene)] was formed and second hydrogenation was proceeded to produce THDMCPD [tetrahydrodi (methylcyclopentadiene)], the ratio of exo to endo THDMCPD was varied by the control of 2nd hydrogenation temperature. To improve the process, continuous 1st and 2nd hydrogenation conditions were established by using the 2nd stage heat controllable reactor. Also, catalytic activities were compared by the use of halogenized aluminum, metal halides and solid acids catalysts on the isomerization reaction from endo to exo THDMCPD.