• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.400-403
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• 2004

A non-heat기leafed steel does not need quenching and tempering processes that are called a heat treatment differently from conventional steel. Since the tensile strength of this steel is higher than 900MPa, a conventional forming process should be changed to incremental forming process such as a cross wedge rolling that requires lower load capacity than conventional ones. In this paper, the cold cross wedge rolling (CWR) die has been designed using CAD/CAE In order to produce near-net-shaped component of ball stud of non-heat-treated cold steel. Finite element analyses were applied in order to investigate process parameters of CWR. Results provide that the stretching angle and the forming angie at knifing zone in CWR process is important parameter to be the stable process under the low friction coefficient condition.

• 한국정밀공학회지
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• 제28권3호
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• pp.301-307
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• 2011

In this paper, effects of major design parameters of cold forging dies on die mechanics are quantitatively investigated with emphasis on shrink fit using a thermoelastic finite element method. A ball-stud cold forging process found in a cold forging company is selected as a test process and the effects of die insert material, magnitude of shrink fit, dimension of shrink ring, number of shrink rings, partition of die insert and clamping force on effective stress and circumferential stress are analyzed. It has shown that the number of shrink rings, magnitude of shrink fit, and Young's modulus of die insert material have strong influence on compressive circumferential stress in die insert but that the influence of the other design parameters is relatively weak.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2000년도 Proceedings of 5th International Joint Symposium on Microeletronics and Packaging
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• pp.57-64
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• 2000

As integrated circuits become more complex, the number of I/O connections per chip grow. Conventional wire-bonding, lead-frame mounting techniques are unable to keep up. The space saved by shrinking die size is lost when the die is packaged in a huge device with hundreds of leads. The solution is bumps; gold, conductive adhesive, but most importantly solder bumps. Virtually every semiconductor manufacturer in the world is using or planning to use bump technology fur their larger and more complex devices. Several wafer-bumping processes used in the manufacture of bumped wafer. Some of the more popular techniques are evaporative, stencil or screen printing, electroplating, electrodes nickel, solder jetting, stud bumping, decal transfer, punch and die, solder injection or extrusion, tacky dot process and ball placement. This paper will discuss the process steps for bumping wafers using these techniques. Critical cleaning is a requirement for each of these processes. Key contaminants that require removal are photoresist and flux residue. Removal of these contaminants requires wet processes, which will not attack, wafer metallization or passivation. research has focused on enhanced cleaning solutions that meet this critical cleaning requirement. Process parameters defining time, temperature, solvency and impingement energy required to solvate and remove residues from bumped wafers will be presented herein.

• 마이크로전자및패키징학회지
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• 제7권1호
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• pp.51-59
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• 2000

As integrated circuits become more complex, the number of I/O connections per chip grow. Conventional wire-bonding, lead-frame mounting techniques are unable to keep up. The space saved by shrinking die size is lost when the die is packaged in a huge device with hundreds of leads. The solution is bumps; gold, conductive adhesive, but most importantly solder bumps. Virtually every semiconductor manufacturer in the world is using or planning to use bump technology for their larger and more complex devices. Several wafer-bumping processes used in the manufacture of bumped wafer. Some of the more popular techniques are evaporative, stencil or screen printing, electroplating, electroless nickel, solder jetting, stud humping, decal transfer, punch and die, solder injection or extrusion, tacky dot process and ball placement. This paper will discuss the process steps for bumping wafers using these techniques. Critical cleaning is a requirement for each of these processes. Key contaminants that require removal are photoresist and flux residue. Removal of these contaminants requires wet processes, which will not attack, wafer metallization or passivation. Research has focused on enhanced cleaning solutions that meet this critical cleaning requirement. Process parameters defining time, temperature, solvency and impingement energy required to solvate and remove residues from bumped wafers will be presented herein.

• 대한기계학회논문집A
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• 제35권8호
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• pp.877-882
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• 2011

스태빌라이저는 선박, 자동차 및 비행기 등에서 과도한 동요를 막고 자세를 안정시키는 장치를 말한다. 본 연구에서 스태빌라이저 링크 POM-GF25%인 복합재료와 금속을 사용하여 제조하였다. 스태빌라이저 강도 평가를 위하여 인장, 압축 및 볼스터드 빠짐으로 실시하였으며, 모두 기준을 만족하였다. 4가지 형태의 로드에서, 널링된 로드가 가장 큰 강도를 나타내었으며, 금속제를 대체할 수 있을 것으로 판단된다. 또한 사출 금형의 재해석으로 스태빌라이저 링크 본체의 형상을 개선하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.329-332
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• 2005

Cross rolling process is one of incremental forming processes to form an axi-symmetric shaped metal component. It can be classified into two types according to the shape of dies, which are a drum type (roll type) and a plate type (straight type). It can also be classified into a wedge type and a ramp type processes according to deformation characteristics of a material. The ramp type die is applied to plate type cross rolling process in cold forming process for forming of teeth of gear or bolt, while the wedge type die is generally utilized to drum type and plate type cross rolling processes in hot forming process. A shape of the ramp type die is usually same as final shape of a product at every section of a progressing direction, while the shape of the wedge type die has different shapes in a progressing direction. In this paper, a rolling of neck part in a ball stud component has been carried out using the plate type cross rolling process with a ramp shaped die. Forming characteristics have been performed using finite element analysis in order to obtain a proper preform for the ramp type plate cross rolling process.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.439-443
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• 2008

We investigate the mechanical behavior of a pre-heat treated steel of ESW95, which is being used for automotive parts including tie-rods to save manufacturing cost and enhance product quality. SCM435 is also investigated to reveal the characteristics of the pre-heat treated steel tested. AFDEX/MAT is used to extract the true stress-strain curve over the large strain with higher accuracy. It has been found that ESW95 has very week strain-hardening behavior which can be negligible compared with SCM435 and that the initial yield strength is quite high and the toughness of ESW95 reaches nearly 75% of SCM435. ESW95 is characterized by the weak strain-hardening behavior and high yield strength that can be lead to minimization of post-processing including heat treatment and straightening. ESW95 and SCM435 are also compared by applying them to ball-stud forging by computer simulation. It is expected that a great deal of change may take place in production as well as in service if the pre-heated steels are adopted.