• 제어로봇시스템학회논문지
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• 제12권10호
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• pp.1029-1034
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• 2006

In this paper, the tracking control of an automatic pipe cutting robot, called APCROM, with a magnetic binder is studied. Using magnetic force APCROM, a wheeled robot, binds itself to the pipe and executes unmanned cutting process. The gravity effect on the movement of APCROM varies as it rotates around the pipe laid in the gravitational field. In addition to the varying gravity effect other types of nonlinear disturbances including backlash in the driving system and the slip between the wheels of APCROM and the pipe also cause degradation in the cutting process. To maintain a constant velocity and consistent cutting performance, the authors adopt a repetitive learning controller (MRLC), which learns the required effort to cancel the tracking errors. An angular-position estimation method based on the MEMS-type accelerometer is also used in conjunction with MRLC to compensate the tracking error caused by slip at the wheels. Experimental results verify the effectiveness of the proposed control scheme.

• Journal of Welding and Joining
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• 제31권3호
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• pp.11-16
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• 2013

Through-silicon-via (TSV) is a major technology in microelectronics for three dimensional high density packaging. The 3-dimensional TSV technology is applied to CMOS sensors, MEMS, HB-LED modules, stacked memories, power and analog, SIP and so on which can be employed to car electronics. The copper electroplating is widely used in the TSV filling process. In this paper, the various Cu filling methods using the control of the plating process were described in detail including recent studies. Via filling behavior by each method was also introduced.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2434-2437
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• 1999

In order to detect the ultrasonic that is generated by the partial discharge of the heavy electric machinery, a Laser Doppler Vibrometer (LDV) was developed. A Michelson type interferometer which employed heterodyne signal process technique was built to measure the frequency and amplitude of vibration. The output signal of the fast photodetector was a frequency modulated signal centered at 40 MHz. The signal from the detector was amplified and downconverted to intermediate frequency centered at 1 MHz after mixing process. The voltage output that was proportional to the velocity of the moving surface(PZT) was obtained using PLL. The spectrum of the FM signal was analyzed and integration method was introduced to obtain amplitude information. This LDV can be used to measure the vibration of MEMS devices, automobiles, HDD and CDP.

• 한국레이저가공학회지
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• 제3권3호
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• pp.21-29
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• 2000

For the direct metal shape processing the powder feed device which is different from the widely used in rapid prototyping. is developed, The three dimensional object is shaped with the melting metal powder. The developed research has applied to rapid prototyping in ultraprecision for MEMS and medical science fields required of rapid manufacture of complex shape. The goal of this study make 3D model which has precision accuracy. Powder spreading apparatus has been more improved because that the control of powder spread is very important in layer manufacturing. It consists of the vibration motor, nozzle and tube which supplies various metal powder. This apparatus could control the spreading velocity that could control powder spreading thickness. Laser on/off switch was adapted because laser scanning velocity must be preserved constantly to prevent heat transformation of laser overheating. The error between sintered thickness md experimental one occurred by shrinkage in sintering melting process. The problem of heat transformation was solved by On/Off switching system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.2195-2197
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• 2000

In order to detect the ultrasonic that is generated by the partial discharge of the heavy electric machinery a Laser Doppler Vibrometer (LDV) is developed. A Michelson type interferometer which employed heterodyne signal process technique is built to measure the frequency and amplitude of vibration. The output signal of the fast photodetector is a frequency modulated signal centered at 40 MHz. The signal from the detector is amplified and converted to intermediate frequency centered at 1 MHz after mixing process. The voltage output that is proportional to the velocity of the moving surface(PZT) is obtained using PLL. The spectrum of the FM signal is analyzed and integration method was introduced to obtain amplitude information. This LDV can be used to measure the vibration of MEMS devices, automobiles, HDD and CDP.

• 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.

• 한국기계가공학회지
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• 제18권8호
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• pp.38-43
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• 2019

Electrowetting on dielectric (EWOD) is a unique method of shape control of small-volume droplets in microfluidic biochips that relies on modification of surface wetting characteristics using electrical methods. In this study, the droplet shape control on various dielectric surfaces by the EWOD and the effect of droplets on the contact angle as well as the shape were investigated. The droplet used in the experiment was on a sample substrate with $5{\mu}l$ of de-ionized water (DIW) using a micropipette, and wettability was measured with a contact angle meter. This study is expected to be helpful for the development of various micro-total-analysis-systems (${\mu}TAS$) and microfluidic systems with MEMS technology.

• 한국기계가공학회지
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• 제17권5호
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• pp.111-116
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• 2018

Thermal fusion bonding is a method to enclose open microchannels fabricated on polymer chips for use in lab-on-a-chip (LOC) devices. Polymethyl methacrylate (PMMA) is utilized in various biomedical-microelectromechanical systems (bio-MEMS) applications, such as medical diagnostic kits, biosensors, and drug delivery systems. These applications utilize PMMAs biochemical compatibility, optical transparency, and mold characteristics. In this paper, we elucidate both the conformational entanglement of PMMA molecules at the contact interfacial regime, and the qualitative nature of the thermal fusion bonding phenomena through systematic molecular dynamics simulations.

• 한국산학기술학회논문지
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• 제18권5호
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• pp.674-680
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• 2017

본 논문은 현재 개인 휴대기기 및 대형 디스플레이 장비의 제어에서 폭넓게 사용되고 있는 터치스크린 패널 (TSP; Touch Screen Panel)의 정상 작동 유무를 확인하기 위한 micro bump 제작 기술에 관한 연구이다. 터치스크린 패널은 감압식, 정전식 등의 여러 가지 방식이 있으나 지금은 편리성에 의하여 정전식 방식이 주도하고 있다. 정전식의 경우 해당하는 좌표의 접촉에 따라 전기적 신호가 변화하게 되고, 이를 통하여 접촉 위치를 확인할 수 있으며 따라서 접촉 위치에 따른 전기 특성 검사가 필수적이다. 검사공정에서 TSP의 모델이 변경됨에 따라 새로운 micro bump를 제작이 및 검사 프로그램의 수정이 필수적이다. 본 논문에서는 새로운 micro bump 제작 시 mask를 사용하지 않아 보다 경제적이며 변화에 대응이 유연한 maskless lithography 시스템을 이용하여 micro bump 제작 가능성에 대하여 확인하였다. 이를 위하여 제작되는 bump의 pitch에 따른 전기장 간섭 시뮬레이션을 진행하였으며, maskless lithogrphy 공정을 적용하기 위한 패턴 이미지를 생성하였다. 이후 MEMS 기술에 해당하는 PR(Photo Resist) 패터닝 공정에서 노광(Lithography) 공정 및 현상(Developing) 공정을 통하여 PR 마스크를 제작한 후 electro-plating 공정을 통하여 micro bump를 제작하였다.

• 한국전기전자재료학회논문지
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• 제23권5호
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• pp.353-357
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• 2010

Recently, silicon etching have received much attention for display industry, nano imprint technology, silicon photonics, and MEMS application. After the etching process, removing of etch mask and residue of sidewall is very important. The investigation of the etched mask removing was carried out by using the ashing, HF dipping and acid cleaning process. Experiment shows that oxygen component of reactive gas and photoresist react with silicon and converting them into the mask fence. It is very difficult to remove by using ashing or acid cleaning process because mask fence consisted of Si and O compounds. However, dilute HF dipping is very effective process for SiOx layer removing. Finally, we found optimized condition for etched mask removing.