• 대한기계학회논문집A
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• 제39권10호
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• pp.1021-1028
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• 2015

최근 휴대폰용 카메라에 널리 사용되는 초소형 렌즈는 사출성형으로 생산되고 있다. 초소형 렌즈는 제품 크기에 비해 러너부가 상태적으로 큰 비중을 차지하는 특성이 있어 이에 특화된 금형설계 및 성형조건의 설정이 필요하다. 본 연구에서는 초소형 렌즈의 사출성형을 위한 박판형 러너구조를 제안하였다. 제안된 러너구조를 적용한 사출성형 공정의 전산모사를 수행하고, 해석 결과를 기존의 원통형 러너의 결과와 비교하였다. 해석 결과 박판형 러너의 경우 원통형 러너에 비해 냉각시간이 상당부분 절감되나 사출압은 다소 증가됨을 확인하였다. 또한 박판형 러너의 두께를 변화시켜가며 해석을 수행하여 유동특성과 냉각특성의 변화를 종합적으로 고려한 최적의 러너두께를 결정하였다.

• 한국정밀공학회지
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• 제32권11호
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• pp.961-968
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• 2015

This study aims to develop an efficient mold structure for the injection molding of a subminiature lens, using shell-type runners instead of traditional cylindrical runners. While the shell runner has the advantage of shorter cooling time due to its thinner geometry, this smaller thickness causes an increase in injection pressure. In this study, the design of the shell runner was modified to contain multiple holes for the purpose of reducing injection pressure. Numerical analyses were performed for shell runners of various hole-shapes, and the resulting filling and cooling characteristics were discussed; the rhombic hole showed the best result for both filling and cooling characteristics. Subsequently, injection molding experiments were performed using an injection mold fabricated based on the rhombic design. The lens parts were successfully molded with highly-reduced cycle time and without degradation of part quality.

• Asian-Australasian Journal of Animal Sciences
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• 제5권3호
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• pp.541-544
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• 1992

Duck eggs from Indigenous (desi), Khaki Campbell and Crossbred (Indian Runner $\times$ Khaki Campbell, $F_1$) were incubated to investigate fertility, hatchability and other related traits. The fertility was highest in crossbred followed by Khaki Campbell and Indigenous ducks respectively. The embryonic mortality was highest in Khaki Campbell followed by Indigenous and crossbred respectively. The embryonic mortality was higher in eggs of 7 days pre-incubation holding period and lower in eggs of 3 days pre-incubation holding period. A significant positive correlation was found between temperature and embryonic mortality as well as relative humidity and embryonic mortality. The hatchability on fertile eggs was highest in crossbred ducks and almost similar in both Khaki Campbell and Indigenous ducks. The hatchability was higher in eggs stored for 3 days in comparison with that of 7 days pre-incubation holding period. A negative correlation was found between temperature and hatchability as well as humidity and hatchability. The normal ducklings hatched out from the eggs of Khaki Campbell ducks was highest followed by Indigenous and crossbred respectively. There was a negative correlation between temperature and normal ducklings hatched as well as relative humidity and normal ducklings hatched. The preincubation holding temperature and relative humidity had positive correlation with dead-in-shell.