http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
후육 벽 PET 용기에 대한 사출 블로우 성형의 유한요소해석
홍석관,송민재,고영배,차백순 한국금형공학회 2018 한국금형공학회지 Vol.12 No.3
Plastic containers which provides the opportunity to reduce transportation costs are lighter and less brittle than glass containers. As a results, efforts to replace glass with plastic are ongoing. The blow molding method is a typical approach in producing plastic containers. Single-stage injection blow molding (ISBM) is one of the blow molding methods. However, the difficulty in controlling the temperature during the injection molding process is considered its main disadvantage. In this study, ISBM process analysis of relatively thick walled containers such as cosmetic containers is carried out. The initial temperature distribution of the preform is deemed to be the most influential factor in the accuracy of blow molding for the thick vessel. In order to accurately predict this, all heat transfer processes of the preform are considered. The validity of this analytical procedure is verified by comparing the cross-sectional thickness with the actual product. Finally, the validated analytical method is used to evaluate the factors affecting the thickness of the final molded part. The ISBM analysis technique for thick walled vessels developed through this study can be used as an effective predictor for preform design and blow process. Key Words: Blow molding, FEM, Injection molding, ISBM
홍석관 한국금형공학회 2018 한국금형공학회지 Vol.12 No.3
Metal 3D printing is very useful for making the injection molds containing complex conformal cooling channels. The most important issue of the 3D printed molds is cost and life cycle. However, powder bed fusion (PBF) methods are vulnerable to fatigue loading because of the presence of pores and rough surfaces. In the present study, the fatigue test was performed to obtain fatigue analysis input data for predicting the durability of a 3D printed injection mold core. The metal 3D printer used to manufacture the specimen was OPM250L from Sodick, and the metal powder material was maraging steel. The ultrasonic fatigue testing method was adopted for the fatigue test. A key advantage of the ultrasonic fatigue method is that 108 ~ 109 long cycle test data or more could be obtained within a relatively short period. Based on the results of the experiment, the effect of heat treatment was negligible. However, there was an apparent difference in durability depending on the presence or absence of the surface treatment
질산염 무기금속 화합물의 분무열분해법에 의한 High-$J_c$ YBCO 박막 제조
홍석관,김재근,김호진,조한우,유석구,안지현,주진호,이희균,홍계원,Hong, Suk-Kwan,Kim, Jae-Gun,Kim, Ho-Jin,Cho, Han-Woo,Yu, Seok-Koo,Ahn, Jin-Hyun,Joo, Jin-Hoo,Lee, Hee-Gyoun,Hong, Gye-Won 한국초전도학회 2006 Progress in superconductivity Vol.8 No.1
High $J_c$ over 1 $MA/cm^2$ YBCO film has been successfully prepared using nitrate precursors by spray pyrolysis method. Aerosol drolpets generated using a concentric spray nozzle were directly sprayed on a $LaAlO_3$(100) single crystal substrate. The cation ratio of precursor solution was Y:Ba:Cu=1:2.65:1.35. The distance between nozzle and substrate was 15 cm. Deposition temperature was ranging from $750^{\circ}C\;to\;800^{\circ}C$. Deposition pressure was 100 Torr, and oxygen partial pressure was varied from 10 Torr to 50 Torr. The microstructure, phase formation, texture development and superconducting properties of deposited films were largely changed with oxygen partial pressure. Deposited films showed a texture with(001) planes parallel to substrate plane. High quality film was obtained when film was deposited at $760^{\circ}C$ with an oxygen partial pressure of 30 Torr. The critical current density($J_c$) of the YBCO film was 1.75 $MA/cm^2$ at 77 K and self-field.
홍석관,황정호,강정진,윤경환 한국유변학회 2015 Korea-Australia rheology journal Vol.27 No.4
Because of increasing interest in the functional surfaces including micro- or nano-patterns, the mass production of such surfaces has been actively researched. Both conventional injection molding (CIM) and injection/compression molding (ICM) of micro-patterns were investigated in the present study. The molding subject is a multi-scale structure that consists of a macro-scale thin plate and micro-scale patterns formed regularly on its surface. The transcription ratios of micro pattern made by CIM and ICM for different flow length were experimentally measured, and the origin of the obtained results was identified through numerical analysis. It was found that the cavity pressure and polymer temperature are the most important factors for micro-pattern filling; in particular, the polymer temperature is the key factor determining the transcription ratio. It was also found that the difference in CIM and ICM micro-pattern transcription ratios originates from the differences in the cavity pressure history if other molding conditions are the same
미세폭 슬리팅 공정에서 유한요소해석을 이용한 성형 정밀도 예측
홍석관,이병문,강정진,김종덕,Hong, Seok-Kwan,Lee, Byung-Moon,Kang, Jeong-Jin,Kim, Jong-Deok 한국금형공학회 2008 한국금형공학회지 Vol.2 No.3
In the electronic products, connector which play a role of board-to-board connection is an essential part. The manufacture process of this connector involves slitting and bending stage. Recently, manufacturing the connector is becoming more and more difficult as miniaturization of the electronic products. In this study, FEM analysis was performed on slitting and bending process for connector terminal with micro width in order to predict the cause of inaccurate dimension of connector terminal which occurs in actual industrial spot.
홍석관,강정진,변철웅,Hong, Seok-Kwan,Kang, Jeong-Jin,Byun, Cheol-Woong 한국레이저가공학회 2008 한국레이저가공학회지 Vol.11 No.3
This study is aimed to analyse the laser glass bonding process numerically. Due to the viscoelastic behaviour of glass, the extremely large deformation of the frit seal is resulted continuously over the transition temperature, so that the thermal boundary condition be changed in the entire calculation process. The commercial FEM algorithm is restrictively able to remesh the large geometrical boundary shape and to adapt the boundary conditions simultaneously. According to our manual adaptation of increasing the laser line intensity to 700 mW/mm, it is possible to estimate the thermal glass bonding process under the fracture stress in principle. But it should be studied further in the case of high laser line intensity.