• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.202-205
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• 2002

The micro-extruding die is a die for manufacturing of fine-wire by extruding process. The fine-wire made from the micro-extruding can be effectively applied to fields of semiconductor parts and medical parts etc. It is predicted that the demand of fine-wire in industry is more and more increasing. In this study $\Phi$ 50${\mu}{\textrm}{m}$ micro-drill which is coated with diamond is used for drilling of super micro-hole sues. For the machining of taper parts of entrance and exit, drill having $\Phi$ 9mm inclination angle 20$^{\circ}$ is used. This is useful for anti tool-breakage in drilling process. After micro-drilling, the polishing process by abrasive is carried out for increasing surface roughness.

• 산업공학
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• 제12권1호
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• pp.49-55
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• 1999

There are many types of holes to be machined on dies manufactured in the car industry. In this paper we introduce a CAM software developed for hole machining of press dies. The CAM software automatically generates NC files for machining holes from CAD data modeled in the CATIA system. A procedure generating NC files consists of three steps. First, the geometric information such as types of holes, hole positions, hole diameters, and hole depths is extracted from CATIA models. And then tools to be used and operation orders are standardized to establish a data base. Finally, NC files are generated by considering the machining conditions such as feedrate and rpm. It is efficient that holes with the same type and the same size should be grouped and machined by a tool to reduce the tool change time. The optimal tool path for machining the holes in a group can be determined by applying an algorithm solving the traveling salesman problem.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.89-92
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• 2001

In this paper, we studied on drilling a microscopic hole of glass using electro-chemical discharge methode. In this research, we fabricated a electro-chemical discharge machine for drilling glass hole. The used parameters to get a fine microscopic hole are the concentration of NaOH solution from 5wt% to 50wt%, the supply voltage from 10V to 40V and the fabricating time from 5 second to 50 second. Also, we used a 0.16mm glass plate. We learned from our experiment that, the fabrication most efficient when supply voltage is 25V-30V and concentration of NaOH solution 35wt% or less.

• 센서학회지
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• 제13권1호
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• pp.72-77
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• 2004

In this paper, we fabricated an apparatus of the electro-chemical discharge drilling for boring narrow through-hole into a glass. In the electrolyte, electro-chemical discharge creates high temperature condition by the electro-discharge energy. Therefore, glass are removed by the accelerated chemical reaction with glasses and chemicals in the high temperature condition. For optimization of the electro-chemical discharge drilling, the process condition was studied experimentally as a function of the electrolyte concentration, supply voltage and process time. The optimum condition was from DC25V to DC30V of applied voltage, 35 wt% NaOH solution.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.334-337
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• 2006

외과수술용 핸드피스는 현재 국내 외 병원에서 사용되고 있는 수술 장비 중 필수 보유 장비이다. 선진수술 기법인 인공관절대체수술 시 뼈(Bone) 절단, 다듬질, 구멍등 초섬세 가공을 목적으로 하는 기기이다. 기존의 공압식(Air Type)은 수술 시 많은 양의 질소(N2 Gas)가 소모됨으로써 질소탱크 보관에 많은 공간이 필요하고 잦은 교체를 필요로 한다. 또한 기계소음과 공압식 호스의 이동으로 시술자와 환자사이에 불편함이 발생하고 감염의 위험성이 있으므로 최근에는 충전식을 선호하고 있다. 이러한 이유로 기존의 공압식을 대체할 배터리형 외과수술용 핸드피스를 연구하게 되었다.

• 한국기계기술학회지
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• 제20권6호
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• pp.941-946
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• 2018

Currently, due to the development of technology, the industry is proceeding with the development of advanced materials with high performance such as light weight, heat resistance and electric conductivity. Carbon Fiber Reinforced Plastics (CFRP) is an excellent material with high heat resistance, high strength and thermal shock resistance. In order to obtain excellent hole shape in CFRP drilling, we compared the modified drill shape and the conventional carbide drill. On the other hand, we determine the proper helix angle by observing the CFRP surface according to the helix angle at the trimming of the end mill proceeding after the hole machining.

• 한국기계가공학회지
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• 제19권9호
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• pp.100-106
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• 2020

This study analyzes the residual stress of AISI 1536V for an engine shaft of the shipbuilding industry and AISI A387 for a reactor shell of the chemical refining industry by the hole drilling method with a strain gauge rosette, which transforms fine mechanical changes into electrical signals. Tensile residual stress is generated in the forging and heat treatment process because specimens are affected by thermal stress and metal transformation stress. In the heat treatment process, the residual stress of AISI A387 is almost 170% the yield strength at 402 MPa. Since during the machining process, variable physical loads are applied to the material, compressive residual stress is generated. Under the same condition, the mechanical properties greatly affect the residual stress during the machining process. After the stress-relieving heat treatment process, the residual stress of AISI A387 is reduced below the yield strength at 182 MPa. Therefore, it is necessary to control the temperature, avoid rapid heat change, and select machining conditions depending on the mechanical properties of materials during manufacturing processes. In addition, to sufficiently reduce the residual stress, it is necessary to study the optimum condition of the stress-relieving heat treatment process for each material.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 금형가공 심포지엄
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• pp.285-291
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• 2002

The shearing process for the sheet metal is normally used in the precision elements such as a frame of TFT-LCD or lead frame of If chips. In these precision elements, the burr formation prevents the system assembly and needs the additional burr removing process. In this paper, we developed the small size NC punching system which has an aligning kinematics between the rectangular shaped punch and die. The punch is driven by an ai cylinder and the sheet metal is moving on the X-Y table system which is driven by two stewing motors. The microprocessor control the whole system and communicate with the monitoring PC by RS232C serial communication protocol. The graphic user interface program in PC monitors nil control the punching system. The cross shaped joint hinge supports the punching die and positioned by two differential screws, whose are installed in perpendicular directions. The aligning between the punch and die is performed using the sheets of half thickness(0.1mm Brass) of the real process for the frame of the TFT-LCD. Using half thickness Brass, the burr formation is magnified and we can decide the aligning direction more easily then using the real thickness(0.2mm) Aluminum. In this paper, the aligning results are measured manually using the SEM photographs and we hope to make the automated aligning procedures using some kinds of image processing techniques.

• 비파괴검사학회지
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• 제33권1호
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• pp.73-79
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• 2013

본 실험에서는 NIMAX재료를 3차원 측정기 및 백색광간섭계를 이용, 진원도 측정과 표면조도 측정을 하여 다음과 같은 결과를 얻었다. 절삭특성은 재료의 경도가 큰 관계로 2F의 조건보다 4F의 조건에서 낮게 나타났으며, 주축 회전수 및 공구 이송이 낮을수록 양호하게 나타났다. 3차원 측정기를 통한 진원도 측정은 절삭분력과 같은 4F 조건에서 양호하게 나타났으며, 주축회전수 1,700 rpm, 공구이송속도 85 mm/min의 조건에서 진원도는 양호한 결과를 보였다. 가공면의 표면거칠기는 2F 조건보다 4F의 조건에서 양호하게 나타났으며, 주축회전수 1,700 rpm, 공구이송속도 55 mm/min의 조건에서 Ra $0.4025{\mu}m$값을 보였다.

• 소성∙가공
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• 제19권6호
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• pp.337-343
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• 2010

Current need of weight reduction in automotive part increases the application for high strength steel (HSS). The various types of high strength steels have been used to produce chassis part, control arms and trailing arms for weight reduction and increasing of fatigue durability such as dual phase steel (DP) and ferrite bainite steel (FB). But, DP and FB steels have proven to show inferiority in durability as well as press formability. Edge cracking occurred often in flange forming and hole expansion processes is the major failure encountered. This paper discussed the behavior of edge stretchability of high strength steel of DP and FB steels. Experimental works have been conducted to study the effect of punch clearance and burr direction on hole expansion ratio (HER). Also finite element simulation (FEM) has been preformed to clarify the mechanism of flange crack and support the experimental results on HER of DP and FB steels. It was simulated the whole process of blanking process following by hole expansion process and ductile fracture criterion named the modified Cockcroft-Latham model which was used to capture the fracture initiation. From the hole expansion tests and FEM simulation studies it was concluded that ferrite bainite steel showed better stretch-flangeability than dual phase steel. It was attributed to the lower work hardening rate of ferrite bainite steel than dual phase steel at the sheared edge.