• 제목/요약/키워드: Process pressure

검색결과 6,551건 처리시간 0.031초

분리된 원주압 보조 액압유도 역 재드로잉공정에 관한 연구 (Study on the Hydromechanical Reverse Redrawing Pprocess Assisted by Separate Radial Pressure)

  • 김봉종;이동우;양동열;박찬승
    • 대한기계학회논문집A
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    • 제20권12호
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    • pp.3728-3740
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    • 1996
  • High-quality cups of deep drawing ratio of more than four cannot be simply drawn by conventional drawing and redrawing processes. In the present study, after the first deep drawing process, subsequent hydromechanical reverse redrawing with controlled radial pressure is employed. In order to increase the deep drawing ratio up to muchmore than four, the radial pressure should be controlled independently of the chamber pressure and thus an optimum forming condition can be found easily by varying the radial pressure. The process has been subjected to finite element analysis by using the rigid-platic material modeling considering all the frictional conditions induced by the hydrostatic pressure. In order to consider the pressure effect on the sheet, the pressure distributions on the flange part and the side wall part are calculated mumerically from simplified Navier-stokes equation. The comparison of the computation with the experiment has shown that the finite element modeling can be conveniently emplyed for the design of the process with reliability from the viewpoint of formability.

사출성형기 실린더와 금형 캐비티의 실시간 모니터링을 이용한 사출성형공정 비교 분석 (Comparative Analysis of Injection Molding Process by On-line Monitoring in Cylinder of Injection Molding Machine and in Cavity of Mold)

  • 박형필;차백순;태준성;최재혁;이병옥
    • 대한기계학회논문집A
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    • 제34권10호
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    • pp.1513-1519
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    • 2010
  • 최근 고품질 제품 생산을 위한 방법으로 센서를 이용한 사출공정모니터링 시스템이 적용되고 있다. 그러나 마이크로 금형, 광학용 금형 및 구조가 복잡한 금형에는 센서 설치가 어렵기 때문에, 공정 모니터링 시스템이 적용되기 어려운 단점이 있다. 본 연구에서는 금형과 사출성형기 노즐의 압력 을 측정하여 공정 모니터링 데이터의 정량적 지수를 정의하고, 성형품 중량에 대한 상관분석을 수행하여 노즐에 설치된 압력센서의 공정모니터링 적용성을 알아보았다. 또한 공정모니터링 데이터를 분석하여 다단사출속도, 보압 및 제한 사출 압력의 영향에 따른 사출성형기의 공정 제어 특성도 알아보았다.

초고압 저온처리에 의한 매자나무의 면역 활성 (Effect of Immune Activity on Berberis koreana Palibin by Ultra High Pressure Low Temperature Process)

  • 김영;한재건;하지혜;정향숙;권민철;안주희;김진철;최근표;정을권;이현용
    • 한국약용작물학회지
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    • 제16권6호
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    • pp.439-445
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    • 2008
  • This study was performed to investigate a methodology of improving immune activities of Berberis koreana Palibin by ultra high pressure on low temperature extraction process. Extraction yield was enhanced up to more than 35% by above process, compare to the control and extraction average. The cytotoxicity on human kidney cell (HEK293) was showed below 20.4%, 21.6% in adding 1.0 mg/ml of the highest concentration. Generally, the extracts by ultra high pressure extraction process showed less toxicity about 5% than the other processes. It could tell that toxic materials that existing in the plant could be reduced or broken by ultra high pressure process due to can be broken bond such the hydrogen bond, the electrostatic bond, the van der Waals bond, and the hydrophobic bond, can be broken by high pressure. The result could be employed to develop a new type of functional food from B. koreana Palibin by low temperature high pressure process.

실시간 폴리싱 압력 제어시스템 개발 (Development of In-Process Polishing Pressure Control System)

  • 오창진;전문식;김옥현
    • 한국정밀공학회지
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    • 제21권1호
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    • pp.109-115
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    • 2004
  • Polishing process has been applied to get extremely fine surfaces, e.g., mirror surfaces such as optical mirrors, lens, molds and etc. Nowadays not only fine surface quality but also submicron order of dimensional accuracy is required for many applications. To meet the requirements polishing process should be provided with an active control of polishing pressure especially for automation of polishing process. In this paper a study on development of an active polishing pressure control system has been presented. A new type of tool assembly has been developed to facilitate the control. The tool is attached to an axis of a polishing machine with a coil spring and control of the polishing pressure is done by the position control of the axis, which needs no additional actuator. The polishing pressure is successfully measured by the measurement of the spring deformation. Control specifications were quantitatively considered by weighting functions and a controller was designed by using loop-shaping technique based on the no synthesis. Some experiments have been executed on a polishing machine with a PC-NC controller. It is shown that the results were coincident well with the theoretical analyses and satisfied the design specifications.

실험계획법에 의한 AZ31마그네슘합금의 마찰접합시 최적공정설계 (Optimization for Friction Welding of AZ31 Mg Alloy by Design of Experiments)

  • 강대민;곽재섭;최종환;박경도
    • 한국기계가공학회지
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    • 제10권4호
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    • pp.64-69
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    • 2011
  • Magnesium alloy has been known as lightweight material in automobile and electronic industry with aluminum alloy, titanium alloy and plastic material. Friction welding is useful to join different kinds of metals and nonferrous metals they are difficult to be joined by such as gas welding, resistance welding and electronic beam welding. In this study, friction welding was performed to investigate optimization process of Mg alloy with a 20mm diameter solid bar. For that, the orthogonal array $(L_{9}(3^{4}))$ was used that contained four factors and each factor had three levels. Control factors were heating pressure, heating time, upsetting pressure and upsetting time. Also tensile tests were carried out to measure mechanical properties for welded conditions. The levels of heating pressure and upsetting pressure used were 15, 25, 35MPa, and 30, 50, 70MPa, respectively. In addition those of heating time and upsetting time were 0.5, 1, 1.5 sec and 3, 4, 5 sec., respectively, rotating speed of 2000rpm. From the experimental results, optimization condition was estimated as follows; heating pressure=35MPa, upsetting pressure=70MPa, heating time=1.5sec, upsetting time=3sec.

Effect of Pressure on Edge Delamination in Chemical Mechanical Polishing of SU-8 Film on Silicon Wafer

  • Park, Sunjoon;Im, Seokyeon;Lee, Hyunseop
    • Tribology and Lubricants
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    • 제33권6호
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    • pp.282-287
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    • 2017
  • SU-8 is an epoxy-type photoresist widely used for the fabrication of high-aspect-ratio (HAR) micro-structures in micro-electro-mechanical systems (MEMS). To fabricate highly integrated structures, chemical mechanical polishing (CMP) has emerged as the preferred manufacturing process for planarizing the MEMS structure. In SU-8 CMP, an oxidizer decomposes organic impurities and particles in the CMP slurry remove the chemically reacted surface of SU-8. To fabricate HAR microstructures using the CMP process, the adhesion between SU-8 and substrate material is important to avoid the delamination of the SU-8 film caused by the mechanical-dominant material removal characteristic. In this study, the friction force during the CMP process is measured with a CMP monitoring system to detect the delamination phenomenon and investigate the delamination of the SU-8 film from the silicon substrate under various pressure conditions. The increase in applied pressure causes an increase in the frictional force and wafer-edge stress concentration. The frictional force measurement shows that the friction force changes according to the delamination phenomenon of the SU-8 film, and that it is possible to monitor the delamination phenomenon during the SU-8 CMP process. The delamination at a high applied pressure is explained by the effect of stress distribution and pad deformation. Consequently, it is necessary to control the pressure of polishing, which can avoid the delamination in SU-8 CMP.

C3-MR 공정의 프로판 사이클 압력 레벨에 따른 에너지효율 최적화를 위한 사례연구 (Case Studies for Optimizing Energy Efficiency of Propane Cycle Pressure Levels on C3-MR Process)

  • 이인규;탁경재;임원섭;문일;김학성;최광호
    • 한국가스학회지
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    • 제15권6호
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    • pp.38-43
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    • 2011
  • 천연가스 액화공정은 극저온에서 운전되며 에너지 소비가 매우 크기 때문에 압축기의 에너지 소모를 최소화하는 것이 공정의 효율 측면에서 중요하다. 여러 가지 천연가스 액화공정 중 C3-MR(Propane Pre-cooled Mixed Refrigerant) 공정의 경우 순수냉매인 프로판과 혼합냉매를 사용하는 두 개의 냉각 사이클로 구성되어있다. 본 연구에서는 C3-MR 공정에서 최적의 프로판 압력 레벨을 찾기 위해 프로판 사이클을 별개로 구성하여 모사하였다. 또한, 압력 레벨에 따른 조건을 변화시켜가며 사례 연구를 수행하고 이를 통해 압축기에서 소모되는 에너지양을 비교하였다. 그 결과 압력 레벨이 높을수록 총 에너지 소모량이 감소하는 것을 확인 할 수 있었다. 압력 레벨이 3일때 보다 압력 레벨이 5일 때 에너지 소모는 약 23.7% 감소하는 값을 얻을 수 있었다.

대기압 이상의 열처리 공정압력이 Cu2ZnSn(S,Se)4(CZTSSe) 박막 성장에 미치는 영향 (Effect of Annealing Process Pressure Over Atmospheric Pressure on Cu2ZnSn(S,Se)4 Thin Film Growth)

  • 이병훈;류혜선;장준성;이인재;김지훈;조은애;김진혁
    • 한국재료학회지
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    • 제29권9호
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    • pp.553-558
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    • 2019
  • $Cu_2ZnSn(S,Se)_4(CZTSSe)$ thin film solar cells areone of the most promising candidates for photovoltaic devices due to their earth-abundant composition, high absorption coefficient and appropriate band gap. The sputtering process is the main challenge to achieving high efficiency of CZTSSe solar cells for industrialization. In this study, we fabricated CZTSSe absorbers on Mo coated soda lime glass using different pressures during the annealing process. As an environmental strategy, the annealing process is performed with S and Se powder, without any toxic $H_2Se$ and/or $H_2S$ gases. Because CZTSSe thin films have a very narrow stable phase region, it is important to control the condition of the annealing process to achieve high efficiency of the solar cell. To identify the effect of process pressure during the sulfo-selenization, we experiment with varying initial pressure from 600 Torr to 800 Torr. We fabricate a CZTSSe thin film solar cell with 8.24 % efficiency, with 435 mV for open circuit voltage($V_{OC}$) and $36.98mA/cm^2$ for short circuit current density($J_{SC}$), under a highest process pressure of 800 Torr.

LED TV 스피커 프레임용 사출 성형공정 구현에 관한 실험적 연구 (Experimental Study on implementation of injection molding process for speaker frame in LED TV)

  • 이선곤;김상현
    • 한국기계가공학회지
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    • 제12권5호
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    • pp.94-101
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    • 2013
  • Injection molding process is one of the most important methods to produce plastic parts with high efficiency and low cost. The objective of this study is to implement the best plastic injection molding process for LED TV speaker frame. Moldflow analysis and simulation of plastic injection molding process were carried out in order to predict optimal modeling operation conditions and then injection molded part was produced various type of resin temperature, filling time and injection pressure variation. the result was that the best injection molding condition is set as 60bar pressure, 2sec filling time and $310^{\circ}C$ degree. The study result would be useful to variety of plastic injection molding process.

일괄처리방식을 이용한 MOD 공정의 변수 최적화 (Optimization of process variables in batch-type MOD process)

  • 정국채;유재무;고재웅;김영국
    • 한국초전도ㆍ저온공학회논문지
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    • 제8권1호
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    • pp.23-25
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    • 2006
  • Optimization of process variables, including oxygen and water partial pressure and also an nesting temperature, was performed in batch-type process to fabricate YBCO films on LaAlO3 single crystal. In this work, YBCO oxide powder was used as a starting precursor for metal-organic deposition(MOD)method. The precursor films were fabricated in batch furnace and they were converted to the epitaxial YBCO films at the same furnace with varying the process variables. The oxygen partial pressure was varied from 100ppm to 2000ppm and the water partial pressure from 1.2% to 12.2%. The window for optimal P(O2) was narrow about 700ppm for batch-type process. YBCO films in bathc-thype MOD process were optimized at 740-770oC and P(H2O) of 2.3%-7.3%.