CAE를 이용한 소형 박육 사출제품의 게이트 위치 및 성형조건 최적화에 관한 연구

오해근 서울産業大學校 産業大學院 2003 국내석사

현재 플라스틱 제품은 살 두께가 갈수록 얇아지고 경량화 되면서 이에 적합한 재료, 가공 기술, 생산 기술들이 발전하고 있다. 본 연구는 미성형과 휨 발생이 현저히 예상되는 소형 박육의 평판 형상인 휴대폰 배터리 Upper Case 제품을 선정하였다. 성형수지는 열악한 환경 하에서도 박육 제품에 적합한 기계적 강도, 치수 안정성, 내구성을 가지고 있으며 전기, 전자 성형품에 많이 이용되고 있는 GE사의 PC(Poly Carbonate) Lexan 141R 을 사용하였다. 또한 성형품의 모델링과 유한 요소의 생성을 위해서는 미국 PTC사의 Pro/Engineer2001을 사용 하였고, CAE해석을 위해서는 호주 Mold flow사의 성형해석 프로그램을 사용하였다. 사출 성형 CAE 시뮬레이션을 이용한 사출 성형품의 게이트 위치와 성형조건(사출 시간, 사출 압력, 냉각수 온도 등)을 변화시켜 해석을 수행한 결과 최적의 게이트 위치와 최적의 사출성형 공정 조건을 구하였다. CAE 해석 결과를 토대로 금형을 제작하고 사출 및 성형실험을 하였으며 3 차원 측정기와 투병기를 이용하여 성형품의 변형량을 측정하고 해석 결과를 비교 검토하였다. 그 결과, CAE 해석 기술을 적용한 변형 해석 결과는 실제 성형품의 측정 결과와 약 5.65-14.9% 오차내에서 잘 일치 하였으며 금형온도와 수지온도의 상승에 따라 변형량이 줄어 들고 있음을 확인 하였다. 본 실험에 적용된 박육 성형품의 최적의 게이트는 사출압력이나 형체력면에서는 3 점 Pin Point 게이트에 비해 나쁘지만 월드라인이나 온도 분포 즉 성형성 및 제품의 외관품질이 양호하기 때문에 1 점 Pin Point 게이트임을 알 수 있었다. 또한 사출기의 형체력은 크게 문제가 되지 않으나 사출 압력과 사출 속도가 높은 고속 사출기를 사용할 경우 소형 박육 제품은 품질이 더 안정됨을 알 수 있었으며 상,하측 코아의 냉각수 온도는 각각 100℃의 조건에서, 사출온도 320℃, 사출압력 120MPa, 사출속도 480㎝/sec, 사출시간 0.8sec, 냉각시간 13sec, 보압시간 2sec 에서 최적 성형작업 조건임을 알 수 있었다. Plastic products have become thinner and lighter these days and the proper material, processing technology and product technology have been developed accordingly. A mobile battery upper case was chosen in this study because it is the flat plate of small thin wall which is expected to have great short shot and wrapping. For moulding resin, PC (Poly Carbonate) Lexan 141R of GE was used which has mechanical strength, measurement stability and durability proper for thin wall product even under poor environment. It is also widely used in electric and electronic moulding products. Pro/Engineering 2001 of PTC(USA) was used for modeling of moulding product and generation of finite element. And a moulding analysis program of Mold flow (Australia)was used for CAE Analysis. The optimal gate position and injection moulding processing condition have been acquired by changing gate position and moulding condition (injection time, injection pressure, coolant temperature, etc.) using injection moulding CAE simulation. Mold production and experiment of injection and moulding were done based on CAE analysis result. And transformation amount of moulding product was measured and analysis result was compared and reviewed using 3D measurement machine and projector. As a result, transformation analysis result using CAE analysis technology was matched with the measurement result of real moulding product within error range of 5.76 ∼ 14.9%. It was also found that transformation amount decreased as temperature of mold and resin increased. The optimal gate of thin wall moulding product applied in this experiment was found to be the Pin Point central 1 gate of 3level mold because weld line or temperature distribution moulding and appearance quality was excellent though its injection pressure or clamping force was not as good as Pin Point central 3. Clamping force of injection molding machine doesn't matter too much but it is found that the quality of small thin-wall product is stabler if faster injection molding machine with high speed and pressure is used. And it is also found that the optimistic injection environment is provided under the condition of 100℃ coolant temperature at top and bottom core, 320℃ of injection temperature, 120MPa of injection pressure, 480cm/sec of injection speed, 0.8sec of injection time, 13sec of cooling time and 2sec of dwelling time.

地方自治團體의 土地政策에 關한 硏究 : 投機抑制施策을 中心으로

오해근 檀國大學校 1991 국내석사

The primary purpose of this study is to cope with the speculation in the land, the rise of land value and the dullness of supply, coming to the fore as an urgent problems on the land policy. For the purpose of correcting the imbalance between the citizens and between the classes concerned with land, we analyzed and examined systematically the ready-made policy related with the field of land. So I presented the methods of improvement. For the sake of coming true this purpose, following after the chapter 1, the introduction, 1 listed the present land policies of Korea, and I explained and compared the fundermental keynotes of land policy of korea and serveral foreign countries in the chapter 2. In the chapter 3, 1 analyzed the reciprocal relations between the local self-government system and the land policy, and in the chapter 4, I analyzed the present problems attended with the excution of the lacal autonomy system and systematically argued about the methods of improvement on the land policy. In conclusion, the immediate necessity related with land of our country is summerized like these-the rise of demand and the deficiency of the land resources, the excessive rise of land value and the unsoundness of dealings in real estate, and the loss of righteousness in the sharing of social wealth, coming from the private ownership of profits attended with the development in the land. For accoplishing the successful use of the land resource attended with the excution of local autonomy system, it seemed that the land policy of our country is improved and introduce the new policies as follow. First, being narrow usable area of our national land, extremely subdivided right to real estate, and prevailing the speculation in real estate as in our country, it is necessary to introduce and excute widely the public land development system for accomplishing the systematic, reasonable and efficient use and sufficient supply of land, and stabilization of the land value. Second, the land saving(for emergency) system must widely apply to the whole national land, which stabilize the land value when the land market is unstable and makes it possible to supplying the land timely, assuming the form of parceling-out or hiring-out. Third, introducing the land preemption system make it possible to easy acquisition of public land. Fourth, through the excution of the taxation policy, repleting with the balance as a standard of land policy, and through the land deal reporting and permission system strechting the whole national land, we should accomplish the stabilization of the land valve and controling the speculation in land. Firth, since the land value, offected with the social-economic motive and development policy, easily move, it is difficult to decide the land value at a fixed point of time. Recently, as it is determined to supress the land value pluralising system and to introduce and exculte the land value unification system, all sorts of land policy should be accmplished following the land value announcement-unification system. Sixth, the special feature of our land succession system is that the farmland is treated as inheritance of propert under the basis of family laws, not considered the distinctive character of agricultural product. Since it is impossible to prevent an independent farmer from collapse and to keep the farmland from fractionation under the present law of inheritance, persent succession system related with the farmland should be improved. Seventh, through the excution of the land trust system, land holder can use the 'Knowhow' of a trust bank related with the business of real estate and use of the land. This system would prevent the sudden rise of land value and help the efficient development of land resources through dividing the landowner and the land user, that keep the land value from realization. Consequently, since the present land problem of our country is very severe and unprecendented, to make matters worse, it is expected that the excution of local autonomy system bring about the speculation in real estate and the extreme rise of land value, it is necessiry to improve the present land policy by introducing all sorts of the land po1icy(or system) mentioned above.

비만인의 지속운동시 운동강도별 생리적 변인의 변화

오해근 계명대학교 2000 국내석사

A Study on the Development of Functional Rice Straw Roughage

오해근 단국대학교 2014 국내박사

The cell wall of rice straw contains a lot of lignin and silica, which are hardly digestible because they are strongly bound to other cellulose and, accordingly, when rice straw is used as roughage for cattle without additional treatment it is low in digestible energy and crude protein content and its cellulose shows low digestibility and intake and, therefore, it cannot support sufficient growth and milk production. Fresh rice straw used in Korea is that baled round without drying after the harvest of rice, and if it is baled with the spray of moisture containing ferment, it is stabilized in about 60 days along with some fermentation and becomes a kind of silage. The moisture content is about 65%, and that of dry rice straw is about 12.3%, and because the main component is cell wall that is less digestible than grass hay, the value of rice straw as feed is very low. Starch pulp, which is a byproduct of starch production, is highly economic but cannot be used alone as livestock feed because of its low protein, mineral, and vitamin content. Thus, untreated rice straw was mixed with microbe, molasses, CMS (condensed molasses solubles), starch pulp and fermented, and the fermented mixture was used as a material of trial products for increasing the value of the products as feed. The mixing ratios of trial product candidates containing fermented rice straw were adjusted through experiments, and each product was fermented at room temperature. This experiment was conducted using microbes related to fermentation in order to select microbe to be used in rice straw fermentation for enhancing the value of low-digestive and low-quality rice straw as feed. Four kinds of microbes were used in this experiment and rice straw was fermented with the Bacillus licheniformis KCTC 1831 was selected finally as the fermenting microbe because of its superior effect in degrading crude fiber, NDF (neutral detergent fiber), ADF (acid detergent fiber). Through experiments for screening microbial fermentation medium, moreover, mass culture medium that was economic and high in culture effect was selected, and the medium was applied in order to enhance the value of low-digestive and low-quality rice straw as feed. According to the results of the farm feeding experiments, the average daily gain rate was 167g higher in the experimental group fed with fermented rice straw than in the control group fed with untreated rice straw. In palatibility test as well, the average daily intake was 650g higher for fermented rice straw than for untreated rice straw. These results show that fermented rice straw is superior to untreated rice straw in both palatibility and gain rate. As growing cattle that have taken a lot of fiber during the growing period show high intake and gain rate after the middle fattening period thanks to their well-developed villi and stomach of high volume-to-capacity ratio, we may expect improved economy from long-term fattening.

역사문화적 도시재생에 관한 연구 : 서울 풍납동 토성 사례를 중심으로

오해근 건국대학교 행정대학원 2019 국내석사