• 한국기계가공학회지
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• 제18권1호
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• pp.101-108
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• 2019

In this study, the hole-cavity resonance technology and the micro pore stainless chip sintering technology were fused to develop silencers with excellent noise attenuation performance even at fluid pressures exceeding 30 bar for the first time at home and abroad. As a result of this study, the noise attenuation performance was greatly improved as reflection, loss, and resonance were made to occur thousands of times simultaneously when fluids pass through the sintered micro pore stainless steel chip sound absorber. The noise of the gas emitted from the bomb without the silencer was shown to be 125dB. And noise test conducted after installation of the silencer showed the noise of 67dB. Given the study results, the amount of noise was greatly reduced in the sintered silencer.

• 센서학회지
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• 제11권3호
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• pp.138-144
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• 2002

스테인레스 봉입형 압력센서를 제작하기 위하여 먼저 반도체 제조 및 식각 공정을 통하여 반도체 압력센서를 제작하였다 그리고 이를 glass molding된 스테인레스 housing에 올려놓고 $50\;{\mu}m$ 두께의 스테인레스 박판을 용접한 후 실리콘 오일을 채워 넣고 봉입하여 압력 범위 10 bar 센서를 완성하였다. 이와 같이 제작한 센서와 XTR105 발신기 전용 회로를 결합하여 $4{\sim}20\;mA$ 출력의 압력 발신기를 제작하고 그 특성을 조사하였다. 온도 보상 전 정확도는 ${\pm}5%$ FS이었으나 보상 후 정확도 ${\pm}1%$ FS로 개선되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1517-1521
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• 2007

On this study, technical aspects were reviewed to drill a series of micro holes (${\phi}$0.10) over 200 within a few micron tolerance in diameter and position on the stainless steel material. Dedicated tools & jigs were designed and manufactured and optimum cutting conditions were found. On this micro hole drilling process, guide drill and step feeding were applied to help chip discharge, prevent drill breakage and finally improve the accuracy of positioning and roundness. The processing results indicated that most holes are distributed within a few micron tolerance in diameter and position intervals.

• Journal of Welding and Joining
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• 제25권2호
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• pp.76-81
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• 2007

Solder bumps have been used to interconnect the chip and substrate, and the size of the solder bump decreases below $100{\mu}m$ to accommodate higher packaging density. In order to fabricate solder bumps, a mold to chip transfer process is suggested in this work. Since the thin stainless steel mold is not wet by the solder, the molten solder is forced to fill the mold cavities with ultrasonic vibration. The solders within the mold cavities are transferred to the Cu pads on the polyimide film through reflow soldering.

• 한국기계가공학회지
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• 제7권4호
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• pp.56-61
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• 2008

Cropping metal materials is widely used for feeding processes of various forming method, such as forging, extrusion, drawing, and upsetting. However, cropping has many weak points, which are material loss in part of cutting, chip creation, and much use of lubrication oil, etc. In this study, instead of cropping, a novel process is proposed to cut metal materials, especially stainless steel bar which is known very difficult to crop. Results of FE-analysis will be shown to verify the proposed method comparing with those of the conventional cropping process. Also, fitting products were successfully forged using the fabricated billet by the proposed process.

• 한국정밀공학회지
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• 제17권11호
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• pp.55-62
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• 2000

The poor machinability material such as austenite stainless steel(STS304) is emphasized on the wide use of HSSE for the tapping operation. The difficulty can be entirely to tapping torque due to chip formation through the hole of tap. The object of this study is to investigate tap geometry affecting the tapping torque from a practical point of view. The study shows that the optima tapping torque is affected by the tap geometry and cutting condition for STS304.

• 대한기계학회논문집B
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• 제30권10호
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• pp.957-965
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• 2006

A high-performance hot chuck is designed as a heating device for an ultra-precision flip-chip bonder with infrared alignment system. Analysis of design requirements for thermal performance leads to a radiative heating mechanism employing two halogen lamps as heating source. The heating tool is made of silicon carbide characterized by high thermal diffusivity and small thermal expansion coefficient. Experimental tests are performed to assess heat-up performance and temperature uniformity of the heating tool. It is revealed that the initial design of hot chuck results in a good heat-up speed but there exist a couple of troubles associated with control and integrity of the device. As a means to resolve the raised issues, a revised version of heating tool is proposed, which consists of a working plate made of silicon carbide and a supporting structure made of stainless steel. The advantages of this two-body heating tool are discussed and the improved features are verified experimentally.

• Food Science and Biotechnology
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• 제16권2호
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• pp.315-319
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• 2007

Biofilm formation on various surfaces is a well-known phenomenon and it has caused pollution problems, health and safety hazards, and substantial economic loss in many areas including the food industry. In the present study, Gamma irradiation at a dose of 2.0 kGy reduced the bacterial counts of Staphylococcus aureus and Pseudomonas aeruginosa suspensions by 6.7 and >6.5 log CFU/mL, respectively, and 30 ppm of sodium hypochlorite effectively reduced the counts of both bacterial suspensions to below the limit of detection ($<2\;log\;CFU/cm^2$). However, in bacterial biofilms attached to stainless steel, gamma irradiation at a dose of 10.0 kGy reduced the counts of S. aureus attached fur 1 hr and overnight by ${\geq}5.1\;and\;5.0\;log\;CFU/cm^2$, respectively. Gamma irradiation at a dose of 1.0 kGy reduced the counts of P. aeruginosa counts to below the limit of detection ($<2\;log\;CFU/cm^2$). On the contrary, S. aureus and P. aeruginosa cells attached to stainless steel chips were difficult to eliminate using sodium hypochlorite. Four hundred ppm of sodium hypochlorite reduced the counts of S. aureus and P. aeruginosa attached for 1 hr by 2.5 and $3.3\;log\;CFU/cm^2$, respectively.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2430-2435
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• 2015

상품을 제조할 때 유연성을 높이기 위해서는 칩의 형상분석이 중요한 문제 중의 하나이다. 본 연구에서는 선삭 작업에서 가공 여유각 변경에 따른 피삭재의 가공특성이 어떻게 변화되는지 분석하고 자 하였다. 피삭재는 3가지로 SM45C(기계구조용탄소강), SCM415(크롬몰리브덴강), STS303(스테인리스강)을 선택하여 정해진 가공조건인 회전속도, 이송속도와 가공 깊이에 따라 분석하였다. 특히, 선삭가공에서의 칩의 형상과 인서트 팁의 마모현상을 분석하였다. 결과적으로 칩의 형상은 피삭재의 재질과 가공깊이, 이송속도에 따라 변화됨을 알 수 있었다. 가공이송속도가 0.10mm/rev일 때와 가공깊이 0.3mm일 때가 유동형 칩으로 재질이나 가공특색을 분류하지 않고 가장 좋은 형상을 보였다.

• 한국기계가공학회지
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• 제10권4호
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• pp.57-63
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• 2011

The aim of this study is to analyze turning process using commercial FEM simulation code. Various simulation models of orthogonal cutting process for 3 layers of metallic material have been simulated and analyzed. The workpiece material used for the orthogonal plane-strain metal cutting simulation consists of three layers, which are Allow Tool Steel, Aluminum and Stainless Steel. The finite element model is composed of a deformable workpiece and a rigid tool. The tool penetrates through the workpiece at a constant speed and constant feed rate. As an analytical result, detailed cutting temperature, strain, pressure, residual stress for both a tool and each layer of workpiece were obtained during the turning process. It has been closely observed that the chip flow curve deforms continuously.