• 한국기계가공학회지
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• 제12권6호
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• pp.10-16
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• 2013

Ultra-fine planing and micro punching are separately used for improving surface roughness and machining dot patterns, respectively, of metal molds. If these separate machining processes are applied for machining of identical molds, there could be an aligning mismatch between the machine tool and the mold. A hybrid machining system combining ultra-fine planing and micro punching was newly developed in this study in order to solve this mismatch; hybrid process technology was also developed for machining dot patterns on a mirror surface of a metal mold. The hybrid machining system has X, Y, and Z axes, and a cam axis for ultra-fine planing. The cam axis and attachable and removable solenoid actuators for micro punching can make large and small sizes of dot patterns, respectively. Ultra-fine planing was applied in the first place to improve the surface roughness of a metal mold; the measured surface roughness was about 20nm. Then, micro punching was applied to machine dot patterns on the same mold. It was possible to control the diameter of the dot patterns by changing the input voltage of the solenoid actuator. Before machining, severe inhomogeneous plastic deformation around the machined dot patterns was also removed by annealing heat treatment. Therefore, it was verified that metal molds with dots patterns for optical products can be machined using a hybrid machining system and the hybrid process technology developed in this study.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.171.1-171.1
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• 2005

• 한국정밀공학회지
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• 제17권12호
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• pp.145-150
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• 2000

Micro punching is one of general methods to fabricate simple holes such as permanent ink-jet printer nozzles. A thin punch, that is need for micro punching, usually has been obtained by mechanical machining. There are some method to obtain a thin punch from a cylindrical rod, e.g., microgrinding and WEDG (Wire Electro-Discharge Grinding). Inefficiently, only one punch can be obtained from these machining methods. In contrast with these methods, many punches can be fabricated simultaneously by electrochemical process. Electrochemical process has usually aimed to obtain very sharp probe for atomic force microscopy (AFM) or scanning tunneling microscopy (STM), and it has not been considered the whole shape of a probe in spite of good merits. In this paper, an ultrathin punch with a tapered shape and a cylindrical tip is newly fabricated by electrochemical process.

• 공업화학
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• 제20권5호
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• pp.561-564
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• 2009

화학적 바인더를 사용하여 활성탄을 고정화시킨 필터 여재(filter media)와 바인더를 사용하지 않고 니들펀치 공정으로 제조한 필터여재를 비교해 보았다. 제조된 콤비네이션 필터는 실차의 내용적과 비슷한 크기의 챔버 내부의 차량용 송풍기에 장착하여 가스제거 효과를 평가하여 보았다. 화학적 바인더를 사용한 캐빈에어필터는 바인더에 의해 활성탄의 흡착기공이 막혀 아세트알데히드 제거 효과가 감소하리라는 예측과 반대로 니들펀칭 공정으로 제조한 필터에 비해 아세트알데히드 1 min 및 30 min 제거효율이 더 높게 나타났다. 니들펀칭 공정에 따르면 활성탄의 소수성결합력(hydrophobic interaction)으로 인해 화학적 바인더를 사용한 캐빈에어필터보다 공극면적(void area)이 상대적으로 더 넓은 것으로 나타났다.

• 소성∙가공
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• 제14권3호
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• pp.277-281
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• 2005

LTCC(Low temperature co-fired ceramic) is being recognized as a significant packaging material of electrical devices for the advantages such as relatively low temperature being needed for process, low conductor resistance and high printing resolution. In the process of LTCC electrical devices, the punched via-hole quality is one of the most important factors on the performance of the device. However, its mechanism is very complicated and optimization of the process seems difficult. In this paper, to clarify the process, via-hole punching experiments were carried out and the punched holes were examined in terms of their burr formation. The effects of thickness of PET sheet, ceramic sheet and punch-to- die clearance on via-hole quality were also discussed. Optimum process conditions are proposed and a factor $\kappa$ is introduced to express effect of the process variables.

• 한국정밀공학회지
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• 제20권5호
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• pp.156-163
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• 2003

In order to investigate the possibility of punching process of brittle material by ball impact, the effects of sealing materials about impact damage of soda-lime glass by small spheres were evaluated experimentally. The using of sealing materials in the development of perfect cone crack was more effective than no using of sealing materials. At the sealing materials condition, in the case of 5mm-thick specimen, Copper and PMMA sealing were more effective in producing a perfect cone formation than the other sealing materials. And in the case of 8mm-thick specimen, Aluminum sealing was most effective in producing a perfect cone formation. The impact velocity range over which perfect cones were formed was influenced by both the thickness of specimen and sealing materials. By a proper selection of sealing materials, the application fur industrial technology for hole (or nozzle) punching process of brittle materials is expected.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 금형가공,미세가공,플라스틱가공 공동 심포지엄
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• pp.193-197
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• 2005

This paper presents a method by which multiple holes of ultra small size can be punched simultaneously. Silicon wafers were used to fabricate punching die. Workpiece used in the present investigation were the rolled pure copper of $3{\mu}m$ in thickness and CP titanium of $1.5{\mu}m$ in thickness. The metal foils were punched with the dies and arrays of circular and rectangular holes were made. The diameter of holes ranges from $2-10{\mu}m$. The process set-up is similar to that of the flexible rubber pad forming or Guerin process. Arrays of holes were punched successfully in one step forming. The punched holes were examined in terms of their dimensions, surface qualities, and potential defect. The effects of the die hole dimension on ultra small size hole formation of the thin foil were discussed. The optimum process condition such as proper die shape and diameter-thickness ratio (d/t) were also discussed. The results in this paper show that the present method can be successfully applied to the fabrication of ultra small size hole array in a one step operation.

• 한국공작기계학회논문집
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• 제16권5호
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• pp.166-171
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• 2007

In this paper Research development about a micro metal forming manufacturing system has been developed. A micro forming system has been achieved in Japan and it's developed micro press is limited to single forming process. To coincide with the purpose to be more practical, research and development is necessary about the press which the multi forming process is possible. We set the development of the equipment including micro deep drawing, micro punching and micro restriking process to the goal. To achieve this goal, we set the application product to a micro thin foil valve which is used in the micro pump module. The compound die set has been designed and manufactured to make two step process. The material of thin foil valve is SUS-304 and its thickness is 50$\mu$m. We can get a good forming results from micro punching experiments in this paper.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 추계학술대회논문집
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• pp.176-181
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• 1997

During a compression molding of continuous fiber reinforced composites, the separation of matrix and fiber is caused by the flow of the molding process. As the characteristics of the products are greatly dependent on the separation, it is very important to clarify the separation in relation to molding condition, degree of needle punching number on the degree of nonhomogeneity are studied.

• 한국공작기계학회논문집
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• 제13권3호
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• pp.61-67
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• 2004

In micro hole punching process the burr occurs inevitably, but the burr must be minimized in order to improve the quality and accuracy of the product. In this study, magnetic field-assisted polishing technique is applied to remove the burr which exists in nozzles for ink-jet printer head and proved to be a feasible for deburring by experiment. The deburring characteristics of sheet metals was investigated changing with polishing time and magnetic abrasive size. After the deburring, the burr size has remarkably reduced and roundness of the hole also has improved.