• Proceedings of the Korean Institute of Resources Recycling Conference
• /
• 2005.05a
• /
• pp.113-118
• /
• 2005

Recycle methodology was researched on the HIPS(High Impact Poly Styrene) materials which are used in modern industry widely, For the various mixing ratio between virgin pellets of HIPS and recycled ones, tensile strength and shrinkage ratio were analyzed with injection molding experiments and numerical simulations. In addition, the deviations of dimensional accuracy were observed in accordance with various molding conditions. Molding conditions such as mold and melt temperature were changed by 3 steps. Mixing ratio between virgin pellets of HIPS and recycled ones were under controlled with 15%, 30% and 45%.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.6
• /
• pp.3448-3454
• /
• 2014

Generally existing structure analysis was applied to elastic analysis basically in practice. Considering the nonlinear material and the nonlinear geometric to be a more precise analysis, for this reason, The necessity for a structual analysis have been constantly required. Therefore, after optimization is performed, designed a simple model which is applied the principle of nonlinear in this study, a structural analysis of existing experienced users, have a aims at presenting theory and a method in order to perform anyone the analysis easily. In this study, the proposed model applied to die ribs, Regarding the shear load, less strain and stress was generated but strength was sufficient. The initial strain and stress was reconfigured to fit the size and shape, A hyperstudy in conjunction with Abaqus with nonlinear structural analysis, revealed an acceptable maximum and minimum range of stress and under the conditions of minimum strain, the plate made with a constant increment. In the experimental models, the plate thickness was given a power of 40 Newton, according to the thickness of the press die through an iterative process. When the stress and strain was applied to the die thickness, 7-8mm thickness could be obtained by optimizing.

• Journal of Adhesion and Interface
• /
• v.17 no.1
• /
• pp.15-20
• /
• 2016

Fiber arrangement was important for fiber reinforced thermoplastic composites using injection fabrication. In this work, fiber arrangement in CF/PP was investigated to use electrical resistance (ER) method during injection times. There were 3 types of injection products of CF/PP with different ER change ratio by fiber arrangement. High ER change ratio case of injection CF/PP products had better increased tensile strength. This reason was due to the fiber arrangement of CF/PP by injection. Fractured surface and contact angle of CF/PP products were used to evaluate for injection product quality. Uniform fiber arrangement of CF/PP by injection type exhibited the uniform heat condition of melted CF/PP. Steady thermal transfer effect occurred from melted CF/PP to steel injection mold. Steady thermal transfer effect of CF/PP was transmitted to high ER change ratio of mold. Ultimately, good condition CF/PP product by injection molding method could be predicted by using ER method.

• Composites Research
• /
• v.23 no.3
• /
• pp.58-63
• /
• 2010

Tensile and flexural properties and electrical conductivity of MWCNT/epoxy composites with different aspect ratios of MWCNTs were compared. The MWCNT/epoxy mixtures were prepared by mechanical dispersion methods using a homomixer and a three-roll mill, and then composite samples were fabricated by compression molding process. The fractured surfaces of the samples were observed by SEM in order to evaluate the degree of dispersion of MWCNTs. The addition of MWCNTs into epoxy resin improved its tensile strength by 7.0% while its flexural strength increased slightly as compared with the one without MWCNTs. In the case of MWCNTs having highest aspect ratio, the mechanical properties of the composites were decreased. When the contents of CM-95 MWCNTs were varied, maximum of tensile and flexural strengths occurred at 1wt% and 0.5wt%, respectively. From the higher contents than these, tensile and flexural strengths of the composites decreased. Electrical conductivities of in-plane and thought-the-thickness directions of MWCNT/epoxy composites were measured using a two-point probe method. They increased with the increase of the aspect ratios and concentrations of MWCNTs in the epoxy matrix.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.8
• /
• pp.877-882
• /
• 2011

Stabilizers are balancing equipment that can reduce the severe rolling of ships, vehicles, and aircraft. We manufactured a stabilizer link using a metal and a composite material with 25% POM-GF. We evaluated the strength of the stabilizer link via tensile, compressive, and ball-stud separation. The standard criteria were satisfied. Of four types of rod, knurled rod has the greatest strength. We improved the shape of the stabilizer-link body by a reanalysis of the injection molding.

• Composites Research
• /
• v.30 no.6
• /
• pp.399-405
• /
• 2017

We manufactured the long fiber-reinforced thermoplastic prototype of under cover using in-line compounding technology, and investigated the formability, mechanical properties and durability of the prototype of under cover. We manufactured the injection mold for the prototype through injection molding analysis and consideration of weight reduction. We investigated the formability of the prototype by evaluating the residual length and dispersion of fiber, and also tested the mechanical properties such as flexural strength, stiffness and impact strength. We investigated the durability of the prototype by the Key-Life Test(KLT) method which is generally used for the automotive interior parts.

• Proceedings of the KAIS Fall Conference
• /
• 2010.11a
• /
• pp.301-304
• /
• 2010

본 논문에서는 다수 캐비티 금형의 러너 내 불균일한 전단분포로 인해 발생되는 충전불균형에 따른 치수정밀도, 기계적 강도 등 물성의 차이가 발생되는 문제점을 해소하기 위해서 수지가 처음 분기되는 2차 러너의 구조에 변화를 주어 다수 캐비티 사출성형에서 충전균형을 위한 러너시스템을 제시하였다. 이 러너시스템은 전단률차이에 의한 즉, 온도가 불균일한 수지의 흐름을 혼합함으로써 수지의 흐름을 균일하게 하여 충전균형을 이루도록 하였다. PP수지를 대상으로 각 캐비티 간 균형충전에 대해 이 러너시스템이 효과가 있는지 검증하기 위해 CAE프로그램(Moldflow)을 이용한 유동해석을 통해 그 효과를 나타내 보았다.

• The Korean Journal of Rheology
• /
• v.9 no.2
• /
• pp.66-72
• /
• 1997

사출성형품의 품질특성으로 외관, 치수, 기계적 강도 등이 있으나 조립부품으로써 사 될경우에는 치수가 주요한 품질이 된다. 성형품은 용융수지의 특성상 사출공정 중 수축을 일으키므로 이를 고려해서 금형설계가 이루어지지만 실제 사출과정에서 공정변수를 최적화 하여 관리하지 않으면 허용오차 내의 치수를 얻기가 힘들다. 본 논문에서는 주요조립부의 치수가 허용오차 내에서 얻어지도록 설계시 적용된 수축률과 측정된 수축률의 차이를 목적 함수로 하여 최소화 시키며 반복이차계획 알고리즘을 채택한 IDESIGN 프로그램을 이용해 최적 사출성형조건을 구하였다. 제약조건은 성형품의 부위별 수축률 편차 및 싱크마크 깊이 가 공정변수의 부등호 제약식으로 도출되었고 성형이 이루어지는 공정변수의 상하한 값이 최대 및 최소 경계값으로 적용되었다.

• Proceedings of the KAIS Fall Conference
• /
• 2011.12b
• /
• pp.518-520
• /
• 2011

금속분말 쾌속조형법의 한 종류인 DMLS 공정은 사출성형품의 균일한 냉각이 가능한 3차원 냉각시스템을 포함한 코어, 캐비티 제작이 가능하다. 그러나, 코어 및 캐비티 내 미세형상의 경우 DMLS로 제작하기에는 난해하므로 별도 미세 절삭가공을 통해 제작할 필요가 있다. 따라서, 본 연구에서는 DMLS금형강 소재의 미세 절삭가공 특성을 분석하고자 하였으며, 이를 위하여 HIP 공정 적용 전 후 DMLS금형강 소재를 대상으로 미세 절삭가공 실험을 수행하고 버 발생 및 공구마모 경향을 분석하였다. 실험 결과 HIP 적용 전 시편이 강도 및 조직측면에서 미세 절삭가공에 상대적으로 유리함을 확인할 수 있었다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1410-1413
• /
• 2003

Drawing is a basic plastic deformation method and productive manufacturing process make wire. rod and variety section geometry bar. Study for the rod drawing process of rod was researched long littles. but non-axisymmetric drawing process is weak. So metal flow is very irregular in non-axisymmetric drawing process and difficult to define about material deformation generally. In this paper, to solve material deformation, use finite element method and then define suitable shape for rod to hexagonal drawing dies. And research corner filling rate and surface roughness for the high strength steel hexagonal bar produced defined dies.