• Title/Summary/Keyword: Mold Filling Process

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Study on the Application of Casting Flow Simulation with Cut Cell Method by the Casting process (Cut Cell 방법을 활용한 공정별 주조유동해석 적용 연구)

  • Young-Sim Choi
    • Journal of Korea Foundry Society
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    • v.43 no.6
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    • pp.302-309
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    • 2023
  • In general, castings often have complex shapes and significant variations in thickness within a single product, making grid generation for simulations challenging. Casting flows involve multiphase flows, requiring the tracking of the boundary between air and molten metal. Additionally, considerable time is spent calculating pressure fields due to density differences in a numerical analysis. For these reasons, the Cartesian grid system has traditionally been used in mold filling simulations. However, orthogonal grids fail to represent shapes accurately, leading to a momentum loss caused by the stair-like grid patterns on curved and sloped surfaces. This can alter the flow of molten metals and result in incorrect casting process designs. To address this issue, simulations in the Cartesian grid system involve creating a large number of grids to represent shapes more accurately. Alternatively, the Cut Cell method can be applied to address the problems arising from the Cartesian grid system. In this study, analysis results based on the number of grid in the Cartesian grid system for a casting flow analysis were compared with results obtained using the Cut Cell method. Casting flow simulations of actual products during various casting processes were also conducted, and these results were analyzed with and without applying the Cut Cell method.

A STUDY ON THE EVALUATION OF POLYMERIZATION SHRINKAGE OF COMPOSITE AND COMPOMER USING STRAIN GAUGE METHOD (스트레인 게이지법을 이용한 복합레진과 컴포머의 중합수축 평가에 관한 연구)

  • Kim, Yeun-Chul;Kim, Jong-Soo;Kwon, Soon-Won;Kim, Yong-Kee
    • Journal of the korean academy of Pediatric Dentistry
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    • v.29 no.1
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    • pp.19-29
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    • 2002
  • The purpose of this study was to compare the polymerization shrinkage and the compressive strength of composite and compomer cured with two different light sources ; conventional halogen-light curing unit and recently-developed plasma arc curing unit. The 'strain gauge method' was used for determination of polymerization shrinkage and the compressive strength was measured by universal testing machine. The results of the present study can be summarized as follows: 1. Filling materials in polyethylene molds showed the initial expansion in the early phase of polymerization. This was followed by the rapid contraction in volume during the first 60 seconds and gradually diminished as curing process continued. 2. The polymerization shrinkage in tooth samples was generally lower than in the mold samples. 3. The generally lower amount of linear polymerization shrinkage was observed in compomer and plasma arc curing unit group when compared to composite and conventional curing unit. 4. The higher compressive strength values was found in composite groups regardless curing methods. The results of this study strongly support the application of plasma arc system and fluoride-containing compomer in the field of clinical pediatric dentistry claiming its effectiveness in curing the esthetic dental materials and the anticariogenic capacity.

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