• 한국공작기계학회논문집
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• 제10권5호
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• pp.104-109
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• 2001

Nowadays, Industrial competition power is depended on that rapidly produce the customized products. Therefor, it is necessary to reduce period of product development. Thus, concurrent engineering that work many process at a time was appeared and Rapid prototyping was appeared, it is method that rapidly produce the prototype. If the graphic model was made by CAD, the prototype can be made in short term. That provide what the part was directly tested by the worker. It provide a worker with believable data. We study on the influence of surface roughness on injection interval and part angle at FDM.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2001년도 추계산학기술 심포지엄 및 학술대회 발표논문집
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• pp.144-146
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• 2001

본 연구는 사출성형공정상에서 발생할 수 있는 문제점을 설계시에 미리 예측하여 좋은 설계를 얻기 위한 시도이다. 사출성형 관련 설계는 사출금형설계전문가의 축적된 지식과 경험을 활용하여 수행되어 왔으며, 설계에 필요한 설계자의 경험이 전무한 경우 많은 시행오치를 유발하고 있는 실정이다. 본 연구에서는 백라이트 패널을 설계함에 있어 설계초기에 성형시 발생할 수 있는 성형성, 기계적 강도 등의 문제를 수치해석을 통하여 시뮬레이션 함으로써 시행오차를 최소화하고 성형성을 고려한 설계를 구현하고자 시도하였다.

• 한국기계기술학회지
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• 제20권6호
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• pp.824-829
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• 2018

Molding is the root industry of the manufacturing as a means to mass-produce developed prototypes. Molds are typically divided into injection molds and press mold industries. Injection molds produce the products by injection of molten plastic into a mold, and press molds are molded and bended plate. The ejection system, such as eject pins, is used to separate the manufactured products from the mold, which involves a number of hole operations. Location, diameter and depth of holes are often tabulated and managed collectively when designing 2D drawings. The design efficiency was realized by applying CATIA Automation to the 3D model and bringing in the data of the holes in the Excel data.

• 폴리머
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• 제24권4호
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• pp.545-555
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• 2000

사출성형에서 수지의 불안정한 흐름에 의해 성형품에 표면결함이 발생되는데 이는 gate의 치수, 운전조건 그리고 고분자 용융물의 유변학적 성질과 밀접한 관련이 있다. 본 연구에서는 PC, PBT, 그리고 PC/ABS alloy에 대해 다양한 사출속도에서 성형품의 표면결함의 형성에 대해서 조사하였다. 표면결함의 형성을 조사하기 위해 여러 가지 cavity 모양, 즉 기계적 물성 측정에 쓰이는 인장, 굴곡 그리고 충격시편의 형상을 이용하여 이들의 cavity와 gate의 두께를 다양하게 하여 실험하였다. 본 연구를 통해 사출성형의 충진 과정에서 letting에 의한 표면결함은 die swell과 die swell의 지연에 크게 영향을 받음을 관찰할 수 있었다. 큰 die swell은 jetting을 없애는데 유리하나 die swell의 지연이 커지면 jetting을 촉진시킨다. Cavity와 gate의 두께 비를 작게 하면 수지의 종류에 관계없이 jetting과 표면결함을 줄이거나 없앨 수 있다. 또한 작은 두께비는 사출성형에서 고분자 용융물의 안정된 흐름을 유지시키기 위할 작업 조건들의 선택의 폭을 넓게 하여 준다.

• Structural Engineering and Mechanics
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• 제59권1호
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• pp.37-57
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• 2016

Reservoir geomechanics can play an important role in hydrocarbon recovery mechanism. In $CO_2$-EOR process, reservoir geomechanics analysis is concerned with the simultaneous study of fluid flow and the mechanical response of the reservoir under $CO_2$ injection. Accurate prediction of geomechanical effects during $CO_2$ injection will assist in modeling the Carbon dioxide recovery process and making a better design of process and production equipment. This paper deals with the implementation of a program (FORTRAN 90 interface code), which was developed to couple conventional reservoir (ECLIPSE) and geomechanical (ABAQUS) simulators, using a partial coupling algorithm. A geomechanics reservoir partially coupled approach is presented that allows to iteratively take the impact of geomechanics into account in the fluid flow calculations and therefore performs a better prediction of the process. The proposed approach is illustrated on a realistic field case. The reservoir geomechanics coupled models show that in the case of lower maximum bottom hole injection pressure, the cumulative oil production is more than other scenarios. Moreover at the high injection pressures, the production rates will not change with the injection bottom hole pressure variations. Also the FEM analysis of the reservoir showed that at $CO_2$ injection pressure of 11000 Psi the plastic strain has been occurred in the some parts of the reservoir and the related stress path show a critical behavior.

• 한국세라믹학회지
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• 제46권3호
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• pp.229-233
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• 2009

This study has focused on manufacturing technique of powder injection molding of watch case made from zirconia powder. A series of computer simulation process was applied to prediction of the flow pattern in the inside of the mould to clarifying the change of sintering shrinkage depended on flow direction. The material properties of melted feedstock inclusive of the PVT graph and thermal viscosity flowage properties were measured for obtaining the input data in computer simulation. Also, molding experiment was conducted and the results of experiment showed that good agreement with simulation results for flow pattern and weld line location. On the other hand, gravity and inertia effect have an influence on velocity of melt front because of high density of ceramic powder particles in powder injection molding against the polymer injection molding process. In the experiment, the position of melt front was compared with upper gate and lower gate position. The gravity and inertia effect could be confirmed in the experimental results.

• Journal of Power Electronics
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• 제13권2호
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• pp.197-205
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• 2013

In energy injection resonant AC-AC converters, due to the low frequency effect of the AC input envelope and the low energy injection losses requirement, the constant and steady control of the high frequency AC output envelope is still a problem that has not been solved very well. With the aid of system modeling, this paper analyzes the mechanism of the envelope pit on the resonant AC current. The computing methods for the critical damping point, the falling time and the bottom value of the envelope pit are presented as well. Furthermore, this paper concludes the stability precondition of the system AC output. Accordingly, an optimal control method for the AC output envelope is put forward based on the envelope prediction model. This control method can predict system responses dynamically under different series of control decisions. In addition, this control method can select best series of control decisions to make the AC output envelope stable and constant. Simulation and experimental results for a contactless power transfer system verify the control method.

• 한국광학회지
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• 제23권1호
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• pp.42-51
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• 2012

본 논문에서는 패브리 페롯 레이저 다이오드(FP-LD : Fabry-Perot LD)에서 활성층 구조에 따른 주입 잠금 특성을 비교하였다. 편광 및 무편광 다중양자우물 구조와 무편광 벌크 구조의 이득 스펙트럼 및 주입 캐리어 밀도에 따른 최대 이득 특성을 TE, TM 편광에 대하여 계산하였다. 계산된 이득 파라미터를 시영역 대신호 모델에 적용하여 FP-LD의 주입 잠금 특성을 확인한 결과, 무편광 FP-LD가 편광 FP-LD 에 비하여 RIN(Relative Intensity Noise) 특성 면에서 약 3 dB 정도 우수하고, 2.5 Gbps 변조시에 아이 특성이 훨씬 우수함을 알 수 있다.

• 한국자동차공학회논문집
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• 제14권4호
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• pp.164-173
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• 2006

In the electro-hydraulic injector for the common rail Diesel fuel injection system, the injection nozzle is being opened and closed by movement of a injector's needle which is balanced by pressure at the nozzle seat and at the needle control chamber, at the opposite end of the needle. In this study, the piezo actuator was considered as a prime movers in high pressure Diesel injector. Namely a piezo-driven Diesel injector, as a new method driven by piezoelectric energy, has been applied with a purpose to develop the analysis model of the piezo actuator to predict the dynamics characteristics of the hydraulic component(injector) by using the AMESim code. Aimed at simulating the hydraulic behavior of the piezo-driven injector, the circuit model has been developed and verified by comparison with the experimental results. As this research results, we found that the input voltage exerted on piezo stack is the dominant factor which affects on the initial needle behavior of piezo-driven injector than the hydraulic force generated by the constant injection pressure. Also we know the piezo-driven injector has more degrees of freedom in controlling the injection rate with the high pressure than a solenoid-driven injector.

• 한국자동차공학회논문집
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• 제16권2호
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• pp.166-174
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• 2008

Numerical study on the impingement process and the fuel film formation of the hollow-cone fuel spray was conducted under vaporization condition, and the effect of the wall cavity angle on spray-wall impingement structure was investigated. A detailed understanding of this phenomena will help in designing injection systems and controlling the strategies to improve engine performance and exhaust emissions of the Gasoline Direct Injection (GDI) engine. The improved Abramzon model was used to model the spray vaporization process and the Gosman model was adopted for modeling of spray-wall impingement process. The calculated results of the spray-wall impingement process were compared with experimental results. The velocity field of the ambient gas, the Sauter Mean Diameter (SMD) and the generated fuel film on the wall, which are difficult to obtain by the experimental method, were also calculated and discussed. It was found that the radial distance after the wall impingement and the SMD decreased with increasing the cavity angle and the temperature.