• 제목/요약/키워드: Mold flow

검색결과 480건 처리시간 0.024초

구리봉의 연속주조금형에 사용된 아세틸렌 화염 도형의 최적화 (Optimization of Mold Coating Condition with Acetylene Soot in Continuous Casting of Copper Rod)

  • 김재욱;김영태;오규환;나형용
    • 한국주조공학회지
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    • 제16권2호
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    • pp.158-164
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    • 1996
  • In copper continuous casting, the soot, which is the incomplete pyrolitic product of acetylene, has been used as a mold coat. In this work, under constant acetylene pressure, the characteristics of soot and the optimum condition of sooting were investigated with different acetylene and oxygen flow rate. The soot particles deposited on the mold surface had mainly spherical shape and their sizes were about 20nm. After reaction with melt, their shapes were changed into polygonal type due to the graphitization. With increasing oxygen flow rate up to $0.6{\ell}/min$, the amount of residues of soot after heat treatment were kept nearly constant. But the amount of residues increased rapidly with further increasing oxygen flow rate. Degree of graphitization was maximum at $0.4{\ell}/min$ and $5{\ell}/min$ of oxygen and acetylene flow rate, respectively.

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충전과 상변화 현상을 포함한 주조과정에 대한 연구 (A Study of a Simultaneous Filling and Solidification During Casting Process)

  • 임익태;김우승
    • 대한기계학회논문집B
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    • 제23권8호
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    • pp.987-996
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    • 1999
  • An algorithm for modeling the filling of metal into a mold and solidification has been developed. This algorithm uses the implicit VOF method for a filling and a general implicit source-based method for solidification. The model for simultaneous filling and solidification is applied to the two-dimensional filling and solidification of a square cavity. The effects of the wall temperature and gate position on the solidification are examined. The mixed natural convection flow and residual flow resulting from the completion of a filling are included in this study to investigate the coupled effects of the filling and natural convection on solidification. Two different filling configurations (assisting flow and opposite flow due to the gate position) are analysed to study the effects of residual flow on solidification. The results clearly show the necessity to carry out a coupled filling and solidification analysis including the effect of natural convection.

SMC 압축성형공정의 모델링 및 유한요소법을 이용한 열유동 해석 (Finite Element Analysis of the Flow in SMC Compression Molding and Its Applications)

  • 이응식;윤성기
    • 대한기계학회논문집
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    • 제18권11호
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    • pp.3084-3090
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    • 1994
  • A new flow model is developed for the analysis of compression molding of sheet molding compounds(SMC) and penalty finite element formulation is presented to predict flow front progressions more accurately. In this model SMC is assumed nonisothermal fluid, which has different viscosities in extension and in shear. The flow is allowed to slip at the mold and is resisted by friction force which is proportional to the relative velocity at mold surface. For the verification of the model, the press force and flow patterns are compared with those of experiments and available results by other works in this field. It is also demonstrated, using the computational procedure described and the proposed model, that optimal initial charge shapes for the filling can be effectively computed.

연속주조공정에서의 유동과 응고에 대한 유한요소 모델링 (A Finite Element Modeling on the Fluid Flow and Solidification in a Continuous Casting Process)

  • 김태헌;김덕수;최형철;김우승;이세균
    • 대한기계학회논문집B
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    • 제23권7호
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    • pp.820-830
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    • 1999
  • The coupled turbulent flow and solidification is considered in a typical slab continuous easting process using commercial program FIDAP. Standard $k-{\varepsilon}$ turbulence model is modified to decay turbulent viscosity in the mushy zone and laminar viscosity is set to a sufficiently large value at the solid region. This coupled turbulent flow and solidification model also contains thermal contact resistance due to the mold powder and air gap between the strand and mold using an effective thermal conductivity. From the computed flow pattern, the trajectory of inclusion particles was calculated. The comparison between the predicted and experimental solidified shell thickness shows a good agreement.

급속 가열에 의한 사출성형품의 복굴절특성 개선 (Improvement of Birefringence Characteristics of Injection-Molded Plastic Parts by Rapid Heating)

  • 박근;김병훈
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 춘계학술대회 논문집
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    • pp.195-198
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    • 2007
  • The present work focuses on the prediction of birefringence in injection-molded plastic part and its improvement by rapid mold heating. To calculate birefringence, flow-induced residual stress is computed through a fully three-dimensional injection molding analysis. Then the stress-optical law is applied from which the order of birefringence can be evaluated and visualized. The birefringence patterns are predicted for a rectangular plate with a variation of mold temperatures, which shows that the amount of molecular orientation and birefringence level decreases with an increase of mold temperature. The effect of mold temperature on the order of birefringence is also studied for a thin-walled rectangular strip, and compared with experimental measurements. Both predicted and experimental patterns of birefringence are in agreements on the observation that the birefringence level diminishes significantly when the mold temperature is raised to above the glass transition temperature.

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온간금형 압축시 구리 분말의 치밀화에 대한 알루미늄 몰드의 영향 (The Effect of an Aluminum Mold on Densification of Copper Powder Under Warm Pressing)

  • 이성철;박태욱;김기태
    • 대한기계학회논문집A
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    • 제32권4호
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    • pp.333-339
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    • 2008
  • Densification behavior of copper powder was investigated to study the effect of an aluminum mold under warm pressing. The low flow stress of an aluminum mold is appropriate to apply hydrostatic stress to powder compacts during compaction under high temperature. The suggested powder metallurgy process is very useful under high temperature since copper powder compacts have higher relative density over axial stress of 100 MPa and show more homogeneity as compared with conventional warm pressing. Elastoplastic constitutive equation proposed by Shima and Oyane was implemented into a finite element program (ABAQUS) for densification behavior under warn pressing by using a metal mold. Finite element results agreed well with experimental data for densification and deformation of copper powder compacts in the mold.

고분자소재 성형용 마이크로 금형에 관한 연구 (A Study about Micro Mold for Polymer Injection)

  • 허영무;신광호;윤길상;정우철
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2004년도 추계학술대회논문집
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    • pp.271-275
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    • 2004
  • In recent industry, according to pursuit the miniaturization and high-precision of machine part with development of new technology as IT and BT, the development of mold manufacturing technology for mass production is accompanied. This study proposes the design of micro mold-base, predicts the error of product through estimating transformation of injection process using FEM. Therefore the mold-base which is suitable for micro injection proposed in this study. Finally, the error of feature is analyzed by measuring the manufactured micro mold-base.

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수평식 연속주조법에 의한 순Al 및 Al-5wt%Si 합금 주괴제조시 주조변수에 관한 고찰 (A Study on the Casting Variables in the Horizontal Continuous Casting of Pure Al and Al-5wt%Si Alloy Rods)

  • 김상동;조형호;김명한
    • 한국주조공학회지
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    • 제13권6호
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    • pp.532-539
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    • 1993
  • The effect of casting variables for making pure Al and Al-5wt%Si alloy rods free from any surface and inside defects was studied by adopting the horizontal continuous casting method with heated mold. The rods were cast under the casting conditions such as the mold temperature of $670{\sim}690^{\circ}C$, water flow rate of $0.2{\sim}0.6{\ell}/min$, and rod diameter of $4{\sim}8mm$, when the melt temperature and mold to cooler distance was fixed at $700^{\circ}C$ and 20mm, respectively. The results represented that the casting speed for good quality rod increased as the water flow rate increased, whereas, the casting speed decreased as the rod diameter or mold temperature increased. The statistical analysis of $2^3$ factorial design was also applied and the results represented that the averaged optimum casting speed for pure Al(302mm/min) was higher than that of Al-5wt%Si alloy(273mm/min) resulting from the difference of superheat applied. The effect of rod diameter on the optimum casting speed was the highest for pure Al as well as Al-5wt%Si alloy. The effect of water flow rate and mold temperature on the optimum casting speed was in decreasing order.

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암시적 VOF법을 이용한 중력주조에서의 충전 및 응고과정에 대한 연구 (A Study on the Filling and Solidification Process During Gravity Casting Using Implicit VOF Method)

  • 임익태;김우승
    • 대한기계학회논문집B
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    • 제24권1호
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    • pp.102-113
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    • 2000
  • In this study, a three-dimensional gravity casting problem has been examined to investigate a coupled phenomenon of the filling and solidification process. This work simultaneously considers the two key phenomena of metal casting : the fluid flow during mold filling, and solidification process. The VOF method is used to analyze the free surface flow during filling and the equivalent specific heat method is employed to model the latent heat release during solidification. The time-implicit filling algorithm is applied to save the computational time for analyzing the mold filling process. The three-dimensional benchmark problem used in the MCWASP VII has been solved using both the implicit and explicit algorithm, and the present results are compared with the benchmark experimental results and the other numerical results.

비대칭형 플라스틱 팬 제품 개발 (Development of Asymmetric Plastic Fan Product)

  • 연규현;김형국
    • 한국기계가공학회지
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    • 제8권2호
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    • pp.53-59
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    • 2009
  • The analysis of injection molding process by CAE is widely used in development of plastic products. That comes from the fact that CAE analysis can reduce trial and error based on optimized design. On this study, by use of MOLDFLOW, the causes of product defects were found and solved by trade-off study. CAE analysis includes Flow-Cool-Warpage Analyses and finally a new mold-die design with better product quality was suggested. On injection molding of round-shaped plastic fan, new mold-die system with 4-tunnel gates located on the edge of a fan disc shows better quality rather than pin-point gate located on the center of a disc. That was effective in terms of flow mark removal and flatness improvement of the product.

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