• International Journal of Precision Engineering and Manufacturing
• /
• 제4권4호
• /
• pp.57-63
• /
• 2003

Machining information such as form accuracy and surface roughness is an important factor for manufacturing precise parts. To this regard, OMM (On the Machine Measurement) has been researched for last several decades to alternate CMM (Coordinate Measurement Machine) process. In this research, the OMM system with a laser displacement sensor was developed for measuring form accuracy and surface roughness of the machined workpiece on the machine tool. The surface roughness was estimated comparing the sensory signal with the reference data measured from master specimen. Also, form accuracy was determined from the moving averaged raw data. In addition, the geometric error map constructed beforehand using the geometric errors of the machine tool was used to compensate the obtained form accuracy. The overall performance was compared with CMM result, and verified the feasibility of the measurement system.

• 한국안전학회지
• /
• 제12권2호
• /
• pp.65-69
• /
• 1997

Especially, Fiber glass Reinforced Plastics(FRP) is the best composite insulating material which has been so far. Therefore, it's worthy of notice to investigate on the corona electrified composite insulating material by surface condition. And then some other materials will be focussed on. In this study, charge decay were measured with charging-time and grid voltage on FRP composite material surface in order to analyze the mechanism. As a result we have studied that the way of the composite glass fiber(GF) and Polymer and the condition of the contaminated surface was different. In case of the GF is mixed with vertical, charge decay speed is fast because the charge is easily leaked. On the other hand, the surface charge decay speed is depend on conductive or insulated of the contaminant.

• Tribology and Lubricants
• /
• 제32권2호
• /
• pp.67-71
• /
• 2016

This study investigates the characteristics of the sapphire wafer chemical mechanical polishing (CMP) process. The material removal rate is one of the most important factors since it has a significant impact on the production efficiency of a sapphire wafer. Some of the factors affecting the material removal rate include the pressure, platen speed and slurry. Among the factors affecting the CMP process, we analyzed the trends in the material removal rate and surface roughness, which are mechanical factors corresponding to both the pressure and platen speed, were analyzed. We also analyzed the increase in the material removal rate, which is proportional to the pressure and platen speed, using the Preston equation. In the experiment, after polishing a 4-inch sapphire wafer with increasing pressure and platen speed, we confirmed the material removal rate via thickness measurements. Further, surface roughness measurements of the sapphire wafer were performed using atomic force microscopy (AFM) equipment. Using the measurement results, we analyzed the trends in the surface roughness with the increase in material removal rate. In addition, the experimental results, confirmed that the material removal rate increases in proportion to the pressure and platen speed. However, the results showed no association between the material removal rate and surface roughness. The surface roughness after the CMP process showed a largely consistent trend. This study demonstrates the possibility to improve the production efficiency of sapphire wafer while maintaining stable quality via mechanical factors associated with the CMP process.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2009년도 추계학술대회 초록집
• /
• pp.251-251
• /
• 2009

• 한국광학회지
• /
• 제15권2호
• /
• pp.89-99
• /
• 2004

금속에서의 흥미로운 광학적 특성들은 주로 표면 폴라리톤(surface polaritons: SP)의 기여에 의해 나타난다. 물질상수(유전율과 투자율)가 모두 음수인 왼손잡이 물질(left-handed materials: LHM)의 표면에서도 두 종류의 SP인 표면 전기-폴라리톤(surface electric-polariton: SEP), 또는, 표면 자기-폴라리톤(surface magnetic-polariton: SMP)이 형성되어 군속도와 위상속도가 서로 반전되는 경우가 발생한다. 본 논문에서는 금속물질과 LHM와 같은 메타물질(metamaterials)의 경계면에서 발생하는 SP의 전파특성을 분산관계를 통하여 분석하였다. 임의의 물질상수를 갖는 두 매질의 경계면에서 SEP와 SMP가 생성될 수 있는 일반화된 조건을 도출하였으며, 양쪽 매질을 통해 전파하는 에너지 비율의 차이에 의해 군속도와 위상속도가 반전된다는 물리적인 원인을 제안하였다. 도출된 SP 생성조건을 이용하여 금속물질과 메타물질의 경계면에서 전파하는 SEP와 SMP의 분산관계를 구하고, 주파수에 따라 다양한 SP의 전파특성이 나타날 수 있음을 보였다. SEP 및 SMP 분산관계로부터 구한 정량화 된 전파특성은 SP가 존재하기 위한 매질의 일반화된 조건과 에너지 전파 비율의 계산으로부터 얻은 결과와 일치함을 확인하였다. 특히, 두 매질 중 어느 한 매질이 LHM이 아니더라도 SP은 위상속도와 군속도가 반전되어 전파될 수 있음을 밝혀내었다.

• 한국정밀공학회지
• /
• 제30권2호
• /
• pp.148-153
• /
• 2013

This study demonstrates a novel hybrid surface polishing process combining non-traditional electrochemical polishing(ECP) with external artificial ultrasonic vibration. ECP, typical noncontact surface polishing process, has been used to improve surface quality without leaving any mechanical scratch marks formed by previous mechanical processes, which can polish work material by electrochemical dissolution between two electrodes surfaces. This research suggests vibration electrochemical polishing(VECP) assisted by ultrasonic vibration for enhancing electrochemical reaction and surface quality compared to the conventional ECP. The localized roughness of work material is measured by atomic force microscopy(AFM) for detailed information on surface. Besides roughness, overall surface quality, material removal rate(MRR), and productivity etc. are compared with conventional ECP.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
• /
• pp.36-41
• /
• 2001

In this work, the changes in the friction force(lateral force) with respect to nanoscale geometric variation were investigated using an Atomic Force Microscope and a Lateral Force Microscope. It could be concluded that the changes in the friction force correspond well to the slope change rather than the surface slope itself, and that the influence of slope change on the frictional behavior is dependent on the magnitude of the slope and the torsional stiffness of the cantilever. Also, the nominal friction force is found to be more significantly affected by the material and the physical-chemical state of the surface rather than by nanoscale geometric steps. However, the change in nanoscale geometric details of the surface cause instantaneous change and slight variation in the friction signal.

• 한국전기전자재료학회논문지
• /
• 제23권3호
• /
• pp.240-244
• /
• 2010

The surface segregation and surface order near the order-disorder phase transition of FeCo alloy was studied through Monte Carlo simulation of an Ising type model Hamiltonian. The results showed that the proper choice of Hamiltonian parameters could reproduce the recent observation of surface order above the transition temperature and that the field term played dominant role.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
• /
• pp.236-239
• /
• 2002

Surface states of silicone polymer treated by plasma were investigated by the analysis by x-ray photoelectron spectroscopy (XPS) and surface voltage decay. Plasma treatment causes the silica-like oxidative layer, which is confirmed with XPS, and lowers surface resistivity with increasing the plasma treatment time. Using the decay time constant of surface voltage, the calculated surface resistivity was compared with the value directly measured by a voltage-current method. A good agreement between two methods was obtained. In addition, we estimated the thermal activation energy for surface conduction, Based on our results, we could understand the relationship between surface chemical states and surface electrical properties.

• 한국표면공학회지
• /
• 제36권3호
• /
• pp.242-250
• /
• 2003

Electrodeposition of Ni was carried out on copper substrate from Ni Sulfamate bath by DC and high frequency pulse current. During the electroplating, bath temperature was steady $60^{\circ}C$ , agitation was applied. Morphology and surface roughness of electrodeposits was investigated with the AFM. Crystalline structure of electrodeposits was investigated with XRD. Also, surface electric resistivity was investigated with 4-point probe. The result of crystalline structure by X-ray diffractometer, in the case of DC, <200> direction was dominant growing direction. But in the case of PC, the ratio of <200> direction vs. other direction decreased. As the pulse frequency increased, the enhanced properties of deposits were shown. With increasing frequency, the degree of surface properties increased DC more than that of PC, eg surface morphology, roughness and the degree of compactness of grains. With increasing duty cycle, the surface properties such as the degree of the morphology, roughness and electroconductivity was deteriorated.