• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.6
• /
• pp.756-760
• /
• 2011

This paper proposed an alignment stage driven by piezo actuators for alignment process of a contact-type lithography. Among contact-type lithography processes, an UV-curable nanoimprint process is an unique process to be able to align patterns on upper and lower layers. An alignment stage of the UV-curable nanoimprint process requires nano-level resolution as well as high stiffness to overcome friction force due to contact moving. In this paper, the alignment stage consists of a compliant mechanism using flexure hinges, piezo actuators for high force generation, and capacitive sensors for high-resolution measurement. The compliant mechanism is implemented by four prismatic-prismatic compliant chains for two degree-of-freedom translations. The compliant mechanism is composed of flexure hinges with high stiffness, and it is directly actuated by the piezo actuators which increases the stiffness of the mechanism, also. The performance of the ultra-precision stage is demonstrated by experiments.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.6
• /
• pp.1486-1496
• /
• 1993

The diamond wheel with superabrasive is required for mirror-like surface grinding of brittle materials. But the conventional dressing mothod can not apply to the diamond wheel with superabrasive. Recently electrolytic dressing method was developed for cast-iron bonded diamond wheel with superabrasive. This technique can take replace of lapping and polishing. Using the electrolytic dressing, the surface roughness of workpiece was improved largely and grinding force was very low and the continuity of the grinding force was also very improved. In this study, the purpose is the realization of mirror-like surface grinding of ferrite with electrolytic dressing of metal bonded diamond wheel. For application of ultraprecision grinding for brittle material, superabrasive wheel, air spindle and inprocess electrolytic dressing were used. In addition, the effects of pick current and pulse width on ground surface were investigated, and the suitable dressing conditions for ferrite were found out.

• Proceedings of the KSME Conference
• /
• 2000.11a
• /
• pp.778-782
• /
• 2000

Deep drawing and ironing are the major process used today in manufacturing of battery case used in cellular phone and IMT-2000 from aluminum. The same technology is utilized in manufacturing of steel or aluminum rectangular cans for components of medical instrument, portable PC, walkman and so on. Most of these processes require multi-stage ironing following the deep drawing and redrawing processes. The practical aspects of this technology are well known and gained through extensive experiment and production know-how. However, the fundamental aspects of theses processes are relatively less known. Thus, it is expected that process simulations using FEM techniques would provide additional detailed information that could be utilized to improve the process condition. This paper illustrates the application of process modeling to deep drawing and redrawing operations with the cellular phone and IMT-2000. A commercially avaliable finite element code LS-DYNA3D was used to simulate deep drawing and redrawing operations.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.4 no.3
• /
• pp.32-38
• /
• 2005

Electrical discharge machining is the method of using thermal energy by electrical discharge. Generally, if the material of workpiece has conductivity even though very hard materials and complicated shape which are difficult to cut such as quenching steel, cemented carbide, diamond and conductive ceramics, the EDM process is favorable one of possible machining processes. But, the process is necessarily required of finish cut and heat treatment because of slow cutting speed, no mirror surface, brittleness and crack due to the residual stress for manufactured goods. In this experimental thesis, the super EDM drilling was developed for high precision semiconductor die steel and for minimization of leadframe width. It was possible to development of EDM drilling machine for high precision semiconductor die with the electrode guide and its modelling and stress analysis. The development of electrode with the copper pipe type was conducted to drill the hole from the diameter of 0.1mm to 3.0mm with the error of from 0.02mm to 0.12mm. From the SEM and EDX analysis, the entrance of the EDM drill was found the resolidification of not only the component of tungsten but also the component of copper.

• Transactions of the Society of Information Storage Systems
• /
• v.1 no.1
• /
• pp.99-107
• /
• 2005

According to recent trend, hard disk drive(HDD) has been smaller and less weight. Therefore, it needs new method of writing position information. In this thesis, a new controller that is suitable for SSW is proposed. The controller accepted SSW technology that is used to write position information in current HDD industry. The important condition to perform SSW is to reach constant velocity decided from the head velocity profile as fast as possible. The constant velocity decides the positional accuracy of spiral pattern and setup time decides the capacity of HDD. The head velocity profile as a reference signal must be designed not to cause resonance mode. The proposed controller was designed with consideration of these 3 elements, and it properly works for SSW. The velocity profile designed with SMART control not only minimizes the jerk, but also does not cause the resonance mode of a plant. After designing a conventional PID controller, it compared with electrical spring technique and ZPET technique.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.257-257
• /
• 2010

디스플레이 산업의 발달로 화상 영상폰, 디지털 카메라, MP4, PMP, 네비게이션, LCD TV등의 가전 제품의 수요증가에 따라 이에 장착되는 LCD 패널의 생산력 향상과 원가 절감을 위한 검사 기술이 요구되고 있다. LCD 검사를 위한 Probe unit은 미세전기기계시스템(MEMS) 공정을 이용하여 제작된다. LCD 검사용 Probe unit는 LCD 가장자리 부분에 전기적 신호(영상신호, 등 기신호, 색상신호)가 인가되도록 하는 수 십 내지 수 백개의 접속 단자가 고밀도로 배치되는데, 이러한 LCD는 제품에 장착되기 전에 시험신호를 인가하여 화면의 불량여부를 검사하기 위한 점등용 부품으로 50 um 이하의 Pin간 거리를 유지하면서 정확한 Pin Alignment를 요구하는 초정밀 부품이다. 본 연구에서는 반도체용 Si wafer에 마스크 공정 및 slit etching 공정을 적용하여 목표인 30 um pitch의 Probe unit을 개발하기 위해 Deep Si Etching(DRIE) 장비를 이용하여 식각 공정에 따른 특성을 평가하였다. 마스크 공정은 500 um 두께의 양면 연마된 반도체용 Si wafer를 이용하였으며, thick PR을 사용하여 마스킹하여 식각공정을 수행하였다. Si 깊은 식각은 $SF_6$ 가스와 Passivation용으로 $C_4F_8$ 가스를 교대로 사용하여 수직방향으로 깊은 식각이 이루어지는 원리이다. SEM 측정 결과 30 um pitch의 공정 목표에 도달하였으며, 식각공정 결과 식각율 6.2 um/min, profile angle $89.1^{\circ}$로 측정되었다. 또한 상부 에칭공정과 이면 에칭공정에서 폭과 wall의 간격이 동일하였으며, 완전히 관통된 양면식각이 이루어졌음을 확인하였다. 또한 실제 사용되는 probe unit의 조립에 적합한 slit 공정을 위한 에칭특성을 조사하였다.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.30 no.10 s.253
• /
• pp.957-965
• /
• 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.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.22 no.2
• /
• pp.127-135
• /
• 2004

The calibration of lens to be used and the planning of photographing planning layout is very important to achieve the requested accuracy in the precision measurement by close-range photogrammetry. Establishment of absolute coordinate system is regarded as another important factor for the purpose of measuring absolute deformation of photogrammetric object. In this study, the following tasks were performed : (1) calibration of super-wide-angle lens or focal length 21mm fer close-range photographing used by 35mm metric camera, (2) development of the measuring system for monitoring of absolute deformation through periodic observation of small area, and, (3) application of this system to monitor the absolute deformation of surface of underwater structure in fixed cycle and to present the efficiency of the system.

• Transactions of Materials Processing
• /
• v.22 no.6
• /
• pp.317-322
• /
• 2013

A radio frequency(R/F) switch connector is widely used in wireless devices such as mobile phone and navigator to check defects of the circuit board of product. The R/F switch connector shell plays a role in protecting the switch connector. Previously, this part was machined using a turning, which is time-consuming and has poor material utilization. Furthermore, the workpiece material of brass containing lead that has excellent machinability has environmentally regulated during recent years. The purpose of the current study was to develop the connector shell by forming through progressive dies including embossing, burring and forging process in order to achieve higher productivity and dimensional accuracy without tool failure. To accomplish this objective, a strip layout was designed and finite element (FE) analysis was performed for each step in the process. Try-out for the connector shell was conducted using progressive die design based on FE-analysis results. Dimensional accuracy of developed part was investigated by scanning electron microscopy. The result of the investigation for the dimensions of the formed connector shell showed that the required dimensional accuracy was satisfied. Moreover, productivity using the progressive die increased four times compared to previous machining process.

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2005.05a
• /
• pp.27-39
• /
• 2005

나노기술은 21세기 초반 첨단산업을 이끌어갈 핵심기술 중의 하나로 여러 나라들이 국가적인차원에서 전략적으로 개발하고 있다. 나노기술은 초정밀 가공기술, 원자 혹은 분자 단위의 조립(조합)기술, 소재공정기술 등의 기술 분야를 포함하며 나노스케일 영역에서 나노소재를 이용(제조 및 가공)하여 새로운 응용분야를 창출해내 거나 기존 산업을 더욱 고도화하는데 기여하는 기술이다. 나노소재는 금속, 세라믹, 고분자, 생체물질 등의 특정 물질 영역에 국한되지 않고 다양한 형태, 다양한 물성을 갖고 있으며 나노기술 구현에 있어서 직접적인 대상 혹은 중간매체에 해당한다. 따라서 나노소재기술은 대단히 광범위한 영역을 포함하는 나노기술의 바탕을 이루는 기반기술 또는 원천기술이라고 할 수 있다. 여러 형태의 나노소재 중에서 가장 저차원(0차원)의 물질에 해당하는 나노분말은 기술적으로 가장 실용화에 근접해 있으며 이미 많은 상용화 사례들이 나타나고 있다. 나노분말 기술은 기술 성숙도 측면에서 뿐만 아니라 확장성(유용성), 신규성(혁신성) 측면에서 대단한 가능성을 갖고 있기 때문에 향후 대단히 빠른 속도로 시장이 확대될 전망이다. 본 발표에서는 나노분말 기술의 개발 현황 및 전망에 대하여 언급하고자 한다.