• 한국산학기술학회논문지
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• 제15권10호
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• pp.5968-5973
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• 2014

게이트 위치는 제품 품질 및 생산성 등에 큰 영향을 미치기 때문에 사출성형에 있어서 게이트 위치를 결정하는 것은 대단히 중요하며 이를 위하여 사출성형 CAE가 적용되고 있다. 사출성형 해석의 증가와 3차원 유한요소의 사용은 더 많은 계산 시간을 필요로 하게 되면서, 컴퓨터 자원을 적게 사용하면서도 빠른 시간 내에 게이트 위치 최적화를 수행하는 것은 중요한 이슈가 되었다. 본 논문에서는 유동 균형과 웰드라인을 고려하기 위하여 유동 거리에 기반한 최적화 기법을 제시하였다. 그리고 원판 형상의 모델에 적용하여 웰드라인이 응력집중이 예상되는 슬릿홀을 피하면서도 유동 균형을 유지하는 결과를 도출하였다.

• 한국기계가공학회지
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• 제12권4호
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• pp.114-122
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• 2013

This study introduces an optimization methodology for the determination of gate location that ensures the melt flow balance within a part cavity of injection mold. A new sequential direct-search scheme based on the recursive reduction of the designer-specified gate design area is developed, and it is integrated with a commercial flow simulation tool for optimization. To quantify the level of melt flow balance, we employ the maximum difference among the fill times for the melt fronts to reach the boundary elements of part cavity as objective function. The proposed methodology is successfully applied in the case study of melt flow balancing in molding of a bar code scanner model. The result shows that the melt flow balance at the optimized gate positions is significantly improved from that for the initial gate position.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.787-791
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• 1996

In injection molding, location of gates have great influence on the quality of plastic parts. Usually, they are located by releated trial and errors of experienced mold designers. In this topic we will present the numerical algorithm for finding the optimal gate locations. Optimization algorithm is devided into two stages. In the first stage, candidated optimal gate locations can be found by geometry of part only; whereas in the next step, more acculate gate locations are selected byiterative computation with optimization part and analysis part. So from the following study, we suggested the modified flow-volume method, which will define the optimal gate locations in injection mold design.

• 한국기계가공학회지
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• 제9권6호
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• pp.21-28
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• 2010

This study shows an optimization procedure for an automatic determination on the gate position to ensure the fill-uniformity within a part cavity by using the injection molding simulation. For an optimization, the maximum pressure-difference within a part cavity induced at the stage of filling is used to evaluate degree of fill-uniformity. In addition, a direct search scheme based on the reduction of design space is developed and applied in the optimization problem. This corresponding proposed methodology was applied in the optimization on the gate location for a CD-tray molding, as a result, showed the improvement of the fill-uniformity within the cavity.

• 한국전산구조공학회논문집
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• 제14권3호
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• pp.267-276
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• 2001

이 논문은 회전식 수문(radial gate)의 구조해석에 근거하여 지지점 위치에 따른 모멘트 분배를 최적화하는 것에 관심을 두고 있다. 회전식 수문(radial gate)의 경제적인 관점에서의 중요성에도 불구하고 이의 지지점 위치에 따른 최적설계에 관한 자료를 찾기 어려운 실정이다. 그래서 본 연구에서는 주판(skin plate)의 곡률 반경, 수심, 동압 등의 주어진 자료를 이요약하여 지지점(gate arm)의 수가 2개인 경우와 3개인 경우에 대하여 곡선형태의 주판(skin plate)에서 지지점 (arm)의 최적 위치를 얻어서 설계자료에 의한 것들과 비교한다. 그 결과 최적 설계에 의한 회전식 수문 (radial gate)의 치수가 설계자료에 의한 것에 비해 현저히 감소되는 것을 알 수 있다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.137-140
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• 1998

An active-matrix LCD using thin film transistors (TFT) has been widely recognized as having potential for high-quality color flat-panel displays. Pixel-Design Array Simulation Tool (PDAST) was used to profoundly understand the gate si후미 distortion and pixel charging capability. which are the most critical limiting factors for high-quality TFT-LCDs. Since PDAST can simulate the gate, data and pixel voltages of a certain pixel on TFT array at any time and at any location on an array, the effect of the resistivity of gate line material on the pixel operations can be effectively analyzed. The gate signal delay, pixel charging ratio and level-shift of the pixel voltage were simulated with varying the parameters. The information obtained from this study could be utilized to design the larger area and finer image quality panel.

• Journal of Biosystems Engineering
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• 제34권2호
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• pp.95-105
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• 2009

A method was proposed which employed control of the drop location of fertilizer particles on a spinner disc to optimize the spread pattern uniformity. The system contained an optical sensor as a feedback mechanism, which measured discharge velocity and location, as well as particle diameters to predict a spread pattern of a single disc. Simulations showed that the feed gate adaptation algorithm produced high quality patterns for any given application rate in the dual disc spreader. The performance of the feed gate control method was assessed using data collected from a Sulky spinner disc spreader. The results showed that it was always possible to find a spread pattern with an acceptable CV lower than 15%, even though the spread pattern was obtained from a rudimentary flat disc with straight radial vanes. A mathematical optimization method was used to find the initial parameter settings for a specially designed experimental spreading arrangement, which included the feed gate control system, for a given flow rate and swath width. Several experiments were carried out to investigate the relationship between the gate opening and flow rate, disc speed and particle velocity, as well as disc speed and predicted landing location of fertilizer particles. All relationships found were highly linear ($r^2$ > 0.96), which showed that the time-of-flight sensor was well suited as a feedback sensor in the rate and uniformity controlled spreading system.

• 한국기계가공학회지
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• 제21권7호
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• pp.84-90
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• 2022

The purpose of the cover housing component of a car door is to protect the terminals of the plug housing that connects the electric control unit on the door side to the car body. Therefore, for a smooth assembly with the plug housing and to prevent contaminants from penetrating into the gaps that occur after assembly, the warpage of the cover housing should be minimized. In this study, to minimize the warpage of the cover housing, optimization was performed for design factors related to the mold and processes based on the injection molding simulation. These design factors include gate location, gate diameter, injection time, resin temperature, mold temperature, and packing pressure. To optimize the design factors, Taguchi's approach to the design of experiments was adopted. The optimal combination of the design factors and levels that minimize warpage was predicted through L₁₈-orthogonal array experiments and main effects analysis. Moreover, the warpage under the optimal design was estimated by the additive model, and it was confirmed through the simulation experiment that the estimated result was quite consistent with the experimental result. Additionally, it was found that the warpage under the optimal design was significantly improved compared to both the warpage under the initial design and the best warpage among the orthogonal array experimental results, which numerically decreased by 36.9% and 23.4%, respectively.

• 한국기계가공학회지
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• 제13권6호
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• pp.73-81
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• 2014

In this paper, multiple gate locations and process conditions under concern are automatically optimized by considering robustness to minimize the injection pressure required to mold an automotive dashboard. Computer simulation-based experiments using orthogonal arrays(OA) and a design-range reduction algorithm are consolidated into an iterative search scheme, which is then used as a tool for the optimization process. The robustness of a design is evaluated using an OA-based simulation of process fluctuations due to noise as well as the signal-to-noise ratio. The optimal design solution for the automotive dashboard shows that the robustness of the injection pressure is significantly improved when compared to the initial design. As a result, both the die clamping force and the pressure distribution in the part cavity are also much improved in terms of their robustness.

• 대한기계학회논문집A
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• 제26권2호
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• pp.406-414
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• 2002

A new approach, referred to as a successive zooming genetic algorithm (SZGA), is Proposed for identifying a global solution for continuous optimization problems. In order to improve the local fine-tuning capability of GA, we introduced a new method whereby the search space is zoomed around the design point with the best fitness per 100 generation. Furthermore, the reliability of the optimized solution is determined based on the theory of probability. To demonstrate the superiority of the proposed algorithm, a simple genetic algorithm, micro genetic algorithm, and the proposed algorithm were tested as regards for the minimization of a multiminima function as well as simple functions. The results confirmed that the proposed SZGA significantly improved the ability of the algorithm to identify a precise global minimum. As an example of structural optimization, the SZGA was applied to the optimal location of support points for weight minimization in the radial gate of a dam structure. The proposed algorithm identified a more exact optimum value than the standard genetic algorithms.