http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
폴리머코어 게이트 크기 변화가 두께 방향 수축률에 미치는 영향에 대한 연구
최한솔,정의철,박준수,김미애,채보혜,김상윤,김용대,윤경환,이성희,Choi, Han-Sol,Jeong, Eui-Chul,Park, Jun-Soo,Kim, Mi-Ae,Chae, Bo-Hye,Kim, Sang-Yun,Kim, Yong-Dae,Yoon, Kyung-Hwan,Lee, Sung-Hee 한국금형공학회 2020 한국금형공학회지 Vol.14 No.1
In this study, the variation of the shrinkage in the thickness direction of the molded parts according to the gate size of the polymer core fabricated through the 3D printer using the SLS method was studied. The polymer cores are laser sintered and the powder material is nylon base PA2200. The polymer cores have lower heat transfer rate and rigidity than the metal core due to the characteristics of the material. Therefore, the injection molding test conditions are set to minimize the deformation of the core during the injection process. The resin used in the injection molding test is a PP material. The packing condition was set to 80, 90 and 100% of the maximum injection pressure for each gate size. The runner diameter used was ∅3mm, and the gates were fabricated in semicircle shapes with cross sections 1, 2, and 3 ㎟, respectively. Thickness measurement was performed for 10 points at 2.5 mm intervals from the point 2.5 mm away from the gate, and the shrinkage to thickness was measured for each point. The shrinkage rate according to the gate size tends to decrease as the cross-sectional area decreases as the maximum injection pressure increases. The average thickness shrinkage rate was close to 0% when the packing pressure was 90% for the gate area of 1mm2. When the holding pressure was set to 100%, the shrinkage was found to decrease by 3% from the standard dimension due to the over-packing phenomenon. Therefore, the smaller the gate, the more closely the molded dimensions can be molded due to the high pressure generation. It was confirmed that precise packing process control is necessary because over-packing phenomenon may occur.
양측성 비대칭 구순열 환자의 치료 : 증례 보고 및 문헌 고찰
최한솔(Han-Sol Choi),김준영(Jun-Young Kim),박지호(Jiho Park),박진후(Jin Hoo Park),정휘동(Hwi-dong Jung),정영수(Young-Soo Jung) 대한구순구개열학회 2020 대한구순구개열학회지 Vol.23 No.2
The correction of asymmetrical bilateral cleft lip is challenging because of its high variability in the lip and nasal tissues. It is the first principle to establish symmetry in bilateral cleft lip of which is indisputable. However, staging and timing in treatment of asymmetrical bilateral cleft including lesser form cleft is controvertible issue. This article aims to report a case about synchronous bilateral nasolabial repair for the patient with asymmetrical bilateral cleft lip with incomplete left and minor form right. and to compare the staging and timing of the repair of asymmetrical bilateral cleft lip including lesser form cleft between the techniques of Mulliken and Fisher.
풋댐퍼가 적용된 경량착륙장치 기반 달착륙선 모사체 개발 및 검증
최한솔(Han-Sol Choi),김영배(Yeong-Bae Kim),정현재(Hyun-Jae Jeong),박정훈(Jeong-Hoon Park),김현(Hyeon Kim),임재혁(Jae Hyuk Lim) 한국소음진동공학회 2021 한국소음진동공학회 논문집 Vol.31 No.5
In this work, we propose a lunar lander demonstrator with lightweight landing gears combined with foot-dampers to absorb landing impact loads and improve landing stability. We select an appropriate aluminum honeycomb and foot-damper model through a set of compression tests and analysis. A set of landing tests with the lunar lander demonstrator is conducted to verify the landing stability considering various ground conditions. In addition, load cells and accelerometers are installed to measure the impact load and shock acceleration on the landing gear to investigate quantitative shock absorption performance. Our test results show that the developed landing gears successfully attenuate the shock and improve landing stability, meeting the design requirements.
SLS 3D 프린터를 이용하여 제작된 PA2200의 단축 반복 인장하중에 따른 피로 특성에 관한 연구
박준수,정의철,최한솔,김미애,윤언경,김용대,원시태,이성희,Park, Jun-Soo,Jeong, Eui-Chul,Choi, Han-Sol,Kim, Mi-Ae,Yun, Eon-Gyeong,Kim, Yong-Dae,Won, Si-Tae,Lee, Sung-Hee 한국금형공학회 2020 한국금형공학회지 Vol.14 No.1
In this study, the fatigue behavior and fatigue life characteristics of PA2200 specimens fabricated by SLS 3D printer were studied. Fatigue tests were performed according to the standard specification (ASTM E468) and fatigue life curves were obtained. In order to perform the fatigue test, mechanical properties were measured according to the test speed of the simple tensile test, and the self-heating temperature of the specimen according to the test speed was measured using an infrared temperature measuring camera in consideration of heat generation due to plastic deformation. There was no significant difference within the set test speed range and the average self-heating temperature was measured at 38.5 ℃. The mechanical strength at the measured temperature showed a relatively small difference from the mechanical strength at room temperature. Fatigue test conditions were established through the preceding experiments, and the loading conditions below the tensile strength at room temperature 23 ℃ were set as the cyclic load. The maximum number of replicates was less than 100,000 cycles, and the fracture behavior of the specimens with the repeated loads showed the characteristics of Racheting. It was confirmed that SLS 3D printing PA2200 material could be applied to the Basquin's S-N diagram for the fatigue life curve of metal materials. SEM images of the fracture surface was obtained to analyze the relationship between the characteristics of the fracture surface and the number of repetitions until failure. Brittle fracture, crazing fracture, grain melting, and porous fracture surface were observed. It was shown that the larger the area of crazing damage, the longer the number of repetitions until fracture.