• Title/Summary/Keyword: Injection materials

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Study of injection molded pattern transferability of double-sided micro-patterned automotive thick light guides (양면 마이크로 패턴 차량용 후육 라이트 가이드의 사출성형 패턴 전사성에 관한 연구)

  • Dong-won Lee;Sang-Yoon Kim;Ji-Woo Kim;Jong-Su Kim;Sung-Hee Lee
    • Design & Manufacturing
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    • v.17 no.4
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    • pp.42-51
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    • 2023
  • In this study, we investigated the injection molding technology of thick-walled light guides, which are parts that control the light source of automotive lamps. Through injection molding analysis, the gate position that can minimize product shrinkage and deformation was selected, and a mold reflecting the analysis results was manufactured to evaluate the effect of injection speed and holding pressure on transferability during micro-pattern molding through experiments. When designing an injection mold for products with varying thicknesses, it was found that installing the gate on the side of the thicker part was advantageous for reducing volume shrinkage and deformation. It was found that the effect of shrinkage due to thickness may be greater than the position of the gate on pattern transferability. The pattern transfer error decreased as the injection speed and holding pressure increased, and it was found that increasing the injection speed was relatively effective.

Modeling of the filling process during resin injection/compression molding

  • Chang, Chih-Yuan
    • Advanced Composite Materials
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    • v.16 no.3
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    • pp.207-221
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    • 2007
  • The filling process of resin injection/compression molding (I/CM) can be divided into injection and compression phases. During the resin injection the mold is kept only partially closed and thus a gap is present between the reinforcements and the upper mold. The gap results in preferential flow path. After the gap is filled with the resin, the compression action initiates and forces the resin to penetrate into the fiber preform. In the present study, the resin flow in the gap is simplified by using the Stokes approximation, while Darcy's law is used to calculate the flow field in the fiber mats. Results show that most of the injected resins enter into the gap during the injection phase. The resin injection time is extremely short so the duration of the filling process is determined by the final closing action of the mold cavity. Compared with resin transfer molding (RTM), I/CM process can reduce the mold filling time or injection pressure significantly.

A study on CAE and injection molding of automotive thick-walled light guide with micro-optical patterns (마이크로 광학 패턴이 있는 차량용 후육 라이트 가이드의 CAE 및 사출성형에 관한 기초연구)

  • Dong-Won Lee;Jong-Su Kim;Hyeon-Hwa Lee;Sung-Hee Lee
    • Design & Manufacturing
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    • v.17 no.3
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    • pp.8-14
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    • 2023
  • In this study, basic research was conducted on manufacturing technology of thick-walled light guide a component that controls the light source of automobile lamps. As a preliminary study for manufacturing the final injection molded parts, a model for analyzing the influence of micro patterns on light guides is presented. The optical characteristics of the light guide were analyzed according to the change of the curvature radius of the micro-optical pattern, and the injection molding characteristics of the light guide according to the change of injection molding conditions were analytically evaluated. It was confirmed that the luminance uniformity improves as the R value decreases for changes in the micro-pattern R value, but it was confirmed that there are technical limitations in actual injection mold core processing and high-replication injection molding. Injection molding analysis showed that cooling channel design is very important compared to general injection molding due to thick-wall characteristics and thickness variation. It was also confirmed that the cooling channel has a great influence on the cycle time and birefringence result due to residual stress. As a result of analyzing the influence of filling time, holding condition, and cooling on shrinkage, it was found that the cooling water temperature has a significant effect on the shrinkage of ultra-fine light guide parts, and the holding condition also has a significant effect.

Energy-level alignment and charge injection at electrodeorganic interfaces

  • Helander, M.G.;Wang, Z.B.;Lu, Z.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.112-114
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    • 2009
  • Charge injection at electrode-organic interfaces is key to the performance, lifetime and stability of organic electronic devices. The link between fundamental material properties and the energy-level alignment at electrode-organic interfaces will be discussed. In addition the impact of the injection barrier height-a parameterization of the energylevel alignment-on device characteristics will also be discussed.

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Measurement of Residual Stress Distribution in Injection-Molded Short Fiber Composites (단섬유 복합재료 사출성형물의 잔류응력 측정)

  • 김상균;이석원;윤재륜
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.10a
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    • pp.61-63
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    • 2001
  • Residual stress distribution in injection-molded short fiber composites was determined using layer-removal method. Polysterene with 3 vol% carbon fibers was injection-molded into the tensile specimen. With milling machine layer-removal process was conducted and the curvature data were acquired. Treuting and Read analysis which is assuming isotropic material, and White analysis considering anisotropy due to the fiber orientation were used to calculate residual stress of the flow direction through the thickness direction and compared with each other.

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Application of a Microcellular Foaming Process of Mixed Materials of LDPE, EVA and Foaming Agent and Estimation of Influence of Each Factor (LDPE, EVA 및 발포제 혼합재료의 초미세 발포 공정 적용과 각 인자의 영향성 평가)

  • Park, Dae-Keun;Cha, Sung-Woon;Hwang, Yun-Dong
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.853-858
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    • 2001
  • Generally, mixed materials of LDPE, EVA and foaming agent are manufactured by crosslinking foaming or chemical foaming process. Above materials were used in a microcellular foaming injection molding process. Influence of each factor such as injection type, temperature of barrel, rate of mixed materials and contents of foaming agent was estimated by DOE(Design of Experiments). As a result of experiments, injection type and rate of LDPE, EVA have an influence on foaming rate. This data can be used in field of application of LDPE and EVA.

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A Study on the Lean Combustion Characteristics with Variation of Combustion Parameter in a Gasoline Direct Injection Engine (직접분사식 가솔린 엔진의 연소제어인자에 따른 희박연소 특성 연구)

  • Park, Cheol-Woong;Oh, Jin-Woo;Kim, Hong-Suk
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.4
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    • pp.39-45
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    • 2012
  • Today gasoline engines for vehicular application are not only faced with stringent emission regulation but also with increasing requirements to better fuel economy, while guaranteeing power density. The spray-guided type gasoline direct injection (GDI) engine has an advantage of improved thermal efficiency and lower harmful emissions. Centrally mounted high pressure injector and adjacent spark plug allow stable lean combustion due to the flexible mixture stratification. In the present study, the performance and emissions characteristics of developed spray-guided type GDI combustion system were evaluated at various excess air ratio conditions. The specific fuel consumption and nitrogen oxides ($NO_x$) emissions were reduced due to the achievement of stable lean combustion under flammability limit. Multiple injection strategy was not helpful to improve fuel consumption while further reduction of $NO_x$ emissions was possible.

Evaluation of the grouting in the sandy ground using bio injection material

  • Kim, Daehyeon;Park, Kyungho
    • Geomechanics and Engineering
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    • v.12 no.5
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    • pp.739-752
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    • 2017
  • This study was intended to evaluate the improved strength of the ground by applying the bio grouting method to a loose sandy ground. The injection material was prepared in the form of cement-like powder, with the bio injection material produced by microbial reactions. The grouting test was conducted under the conditions similar to the field where the bio injection material can be applied. In addition, the injection materials (cement and sodium silicate No. 3) used for Labile Waterglass (LW) method and the conventional grouting methodwere prepared through a two-solution one-step process. The injection into the specimens was done at a pressure of 150 kPa and then, with a bender element, their moduliof elasticity were measured on the 7th, 14th, 21st and 28th curingdays to analyze their strengths according to the duration of curing. It was confirmed that in all injection materials the moduli of elasticity increased over time. In particular, when 30% of the bio injection material was added to 100% cement, the modulus of elasticity tended to increase by about 15%. This confirmed that the applicability became higher when the bio injection material was used in place of the conventional sodium silicate.