• 한국표면공학회지
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• 제19권3호
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• pp.121-127
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• 1986

There are many plating methods already commercially employed in te surface technology. One of the plating methods is electroless (chemical) plating, which is deposited by auto-catalytic reduction of metallic ion with the reducing agent in the plating bath. And it has many advantages comparing with electrolytic plating in respect of properties of deposit, such as corrosion resistance, wear resistance, uniformity, hardness, adhesion and so on. So, electroless plating is the fatest growing process in metallization of plastic and electronic industry. The properties and numerous applications of electroless deposits are attracting more and more attention from finish specifies. Many metal finishers are considering set-up of new electroless line in their shops. This review will be beneficial to domestic metal finishers to understand the real status of present electroless plating technology. It will also provide some knowledge on the economic aspect of electroless plating for the commercial application of specific parts.

• 한국염색가공학회지
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• 제34권3호
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• pp.165-172
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• 2022

Polypropylene(PP) is a textile material with various functions such as eco-friendliness, lightness, and elasticity. Although most synthetic fibers can be dyed and finished, but original PP is difficult to dye or finish due to its extremely hydrophobic properties, so its application expansion is limited. In order to solve this problem, dyeable PP was developed, and various researches on textiles for clothing such as mass production technology, fine fiberization and performance improvement are in progress. Plasma treatment is a processing method for modifying the surface of fabrics, and has effects such as hydrophilization, deepening color, improving adhesion, and surface polymerization. In this study, plasma treatment was applied to study changes in hydrophilization properties of dyeable PP, surface changes before and after plasma treatment and performance according to hydrophilization.

• 한국재료학회지
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• 제24권3호
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• pp.166-173
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• 2014

The effects of printed circuit board electroless nickel immersion gold (ENIG) and organic solderability preservative (OSP) surface finishes on the electromigration reliability and shear strength of Sn-3.5Ag Pb-free solder bump were systematically investigated. In-situ annealing tests were performed in a scanning electron microscope chamber at 130, 150, and $170^{\circ}C$ in order to investigate the growth kinetics of intermetallic compound (IMC). Electromigration lifetime and failure modes were investigated at $150^{\circ}C$ and $1.5{\times}10^5A/cm^2$, while ball shear tests and failure mode analysis were conducted under the high-speed conditions from 10 mm/s to 3000 mm/s. The activation energy of ENIG and OSP surface finishes during annealing were evaluated as 0.84 eV and 0.94 eV, respectively. The solder bumps with ENIG surface finish showed longer electromigration lifetime than OSP surface finish. Shear strengths between ENIG and OSP were similar, and the shear energies decreased with increasing shear speed. Failure analysis showed that electrical and mechanical reliabilities were very closely related to the interfacial IMC stabilities.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.281-286
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• 2001

Titanium alloy conducted in this experimental study has superior corrosive resistant and is mainly used in aerospace, automotive and petro-chemical industries. It is also treated with important materials of domestic goods due to improvement of the standard of living. In this study specimens were processed in the wire EDM after annealing, solution treatment and aging. Results were obtained through repeated experments of main rough process and finish process with the change of process parameters. Processing characteristics such as surface hardness, surfaces roughness, shape of processed surface and components were measured. The results confirmed that the above mentioned elements were improved in accordance with the number of process. Therefore, the optimal wire EDM condition in accord with processing characteristics is proposed in this experiment.

• 마이크로전자및패키징학회지
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• 제30권1호
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• pp.49-54
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• 2023

최근 SIP (System in Packaging) 기술은 고주파(5G 이상) 통신 및 미세 피치 회로 특성을 만족해야 한다. 기존 ENIG (Electroless Ni/Immersion Au Plating) 표면처리는 전송 손실이 증가하여 고주파에 적합하지 않으므로, 니켈 도금층이 없어도 패턴 및 패드의 신뢰성 수준을 만족시킬 수 있는 표면 처리 기술이 검토되고 있다. 본 논문에서는 고주파 통신 대응을 위한 Ni-less 표면처리기술과 소재에 따른 주파수 특성 등에 대한 연구 동향을 조사하였다.

• 한국산업융합학회 논문집
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• 제4권4호
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• pp.365-369
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• 2001

This paper presented a new model of virtualized CNC milling machine. The model verifies the over cut, the under cut and the surface roughness using NC file generated from CAM and cutting condition. The model uses Z-map model to verify workpiece. In this paper, the model used the velocities of x, y and z direction and obtained a center point of a hall end mill for modeling Z-map of workpiece. To investigate the performance of the model, simulation study was carried out. As the results, the model gave geometry accuracy of workpiece, the surface roughness and the chip loads in finish cutting that can predict tool chipping. The virtualized CNC machine can he used a flat end mill, a ball end mill and a rounded end mill.

• 한국공작기계학회논문집
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• 제12권5호
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• pp.40-45
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• 2003

Optical and electronic industries are using lapping and polishing processing as a final finish rather than grinding, because they need more accurate parts of brittles non-metallic materials such as single crystals. Sapphire has been ground by the ultra-precision surface grinder having a glass -ceramic spindle of extremely-low thermal expansion with various cup-type resinoid-bonded diamond wheels of #400-#3000 in grain size. Sapphire can be ground in the ductile mode. And also, the surface roughness and grinding conditions has been clarified. The smooth surface of Sapphire less than 1nm RMS, 1nm Ra can be obtained by the ultra-precision grinding without any polishing process.

• Tribology and Lubricants
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• 제24권6호
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• pp.332-337
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• 2008

This paper presents the surface defect analysis based on the experimental investigation of scribed glasses. The scribing process by a diamond wheel cutter is widely used as a reliable and inexpensive method for sizing of glass sheets. The wheel cutter generates a small median crack on the glass surface, which is then propagated through the glass thickness for complete separation. The surface contour patterns in which are formed during a scribing process are strongly related to wheel cutter parameters such as wheel tip surface finish, tip angle and wheel diameter, and cutting process parameters such as scribing pressure, speed and tooling technique. The scribed surface of a glass sheet provides normal Wallner lines, which represent regular median cracks and crack propagation in glass thickness, and abnormal surface roughness patterns. In this experimental study, normal and abnormal surface topographic patterns are classified based on the surface defect profiles of scribed glass sheets. A normal surface of a scribed glass sheet shows regular Wallner lines with deep median cracks. But some specimens of scribed glass sheets show that abnormal surface profiles of glass sheets in two pieces are represented by a chipping, irregular surface cracks in depth, edge cracks, and combined crack defects. These surface crack patterns are strongly related to easy breakage of the scribed glass imposed by external forces. Thus the scribed glass with abnormal crack patterns should be removed during a quality control process based on the surface defect classification method as demonstrated in this study.

• 한국정밀공학회지
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• 제25권2호
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• pp.28-34
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• 2008

Recently, with the development of high speed machining technology for difficult-cutting materials, to improve the cutting performance of cutting tool, fine surface finish of complex shape tools using magnetic polishing technology is in high demand. This study is, therefore, discussed and compared the cutting characteristics of polished tools by the adopted various magnetic polishing moving types a point of view the cutting forces and the tool life. Moreover, the practicality of magnetic polished tools in the wide range cutting conditions is investigated. From obtained results, It is confirmed that the CW(clockwise) revolution and oscillation type as the polishing moving type is proper and magnetic polished tool shows the excellence in high cutting speed range.

• 한국생산제조학회지
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• 제18권5호
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• pp.469-476
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• 2009

Hard facing overlay welding in high chromium carbide is a representative way of extending the fatigue life or recompensing damage, because workpiece surface is uniformly overlay-welded by alloy material. In general, grinding process is currently used for finish due to hardness of weld material. The development of tool material, such as PCBN, has made it possible to use turning instead of grinding. There are many advantages of hard Owning, as lower equipment costs, shorter setup time, fewer process steps, higher material removal rate, better surface integrity and the elimination of cutting fluid. In this paper, machining characteristics and cutting performance are examined to investigate turning possibility of overly welding in high chromium carbide.