• 한국정밀공학회지
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• 제16권5호통권98호
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• pp.11-18
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• 1999

Recently high speed machining is being studied actively to reduce machining time and to improve machining precision. To perform efficient high speed machining, evaluation of high speed machinability must be studied preferentially and it can be identified by investigation of cutting force. To measure cutting forces in high speed machining, dynamometer which has high natural frequency was newly designed using 3-axes piezo force sensor. For newly designed dynamometer, calibration is conducted with sensitivity of force sensor modulated and proper preload and interference force are investigated experimently. Also, cutting force signals of newly designed dynamometer are compared with those of conventional one in high speed cutting experiment and its superiority is confirmed. Then using newly designed dynamometer, high speed machinability is evaluated about cutting force and tool wear in various cutting conditions.

• 항공우주시스템공학회지
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• 제9권4호
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• pp.23-30
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• 2015

The focal plane image stabilization for a camera is one of the most effective method that can increases the digital camera's image quality by compensating the vibration disturbance. The optical image stabilization can be implemented by making the focal plane to trace the path of incident light. To control the position of focal plane motion compensating stage precisely, a nonlinear control algorithm has been applied by considering coulomb friction which is nonlinear behavior of the compensator system. In our study, we have analyzed the hand shaking vibration using the gyro sensor, and made a mathematical model of compensating stage containing optical sensor and piezo-actuator. Then the nonlinear control algorithm has been designed and its performance has been verified by experiment. In this study, a friction driven peizo-electric actuator with $1{\mu}m$ resolution and 10mm/s speed has been used for stage movement.

• 센서학회지
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• 제20권3호
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• pp.213-218
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• 2011

The load cell is a force sensor and a transducer that is used to convert a physical force into a electrical signal for weighing equipment. Most conventional load cells are widely used a metal foil strain gauge for sensing element when force being applied spring element in order to converts the deformation to electrical signals. The sensitivity of a load cell is limited by its low gauge factor, hysteresis and creep. But silicon-based sensors perform with higher reliability. This paper presents the basic design and development of the silicon type load cell with an SUS630 diaphragm. The load cell consists of two parts the silicon strain gauge and the SUS630 structure with diaphragm. Structure analysis of load cell was researched by theory to optimize the load cell diaphragm design and to determine the position of peizoresistors on a silicon strain gauge. The piezo-resistors are integrated in the four points of silicon strain gauge processed by ion implantation. The thickness of the silicon strain gauge was polished by CMP under 100 ${\mu}M$. The 10 mm diameter SUS630 diaphragm was designed for loads up to 10 kg with 300 ${\mu}M$ of diaphragm thickness. The load cell was successfully tested, the variation of ${\Delta}$R(%) of four points on the silicon strain gauge is good linearity properties and sensitivity.

• 한국진공학회지
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• 제21권1호
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• pp.36-40
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• 2012

마이크로미터 크기의 역학적 공진기의 제작과 그 공진 주파수 변화를 이용하여 질량 변화량을 측정하는 방법에 대해 연구 하였다. 공진기의 공진 주파수를 측정하기 위해서 레이저의 간섭효과를 이용한 광학적 측정법을 사용하였는데 이 방법은 나노미터 스케일의 변위까지 감지할 수 있을 정도로 매우 감도가 높은 측정법이다. 공진기는 압전 세라믹(piezo ceramic) 위에 원자현미경(atomic force microscope)의 캔티레버를 붙여서 만들었는데 이 방법은 압전판이 캔티레버의 공진 주파수로 진동할 때 캔티레버의 변위가 가장 크게 변화됨을 이용한 것이다. 또한, 전자 빔 증착기(e-beam evaporation system)를 사용하여 금을 캔티레버 위에 증착하여 질량을 변화시킨 후에 질량 변화량에 따른 공진주파수의 변화량을 측정하였다. 이 공진기는 질량센서의 역할을 수행할 수 있으며 수 마이크로그램을 감지할 수 있는 감도를 가짐을 확인하였다.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.171-176
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• 2021

Die-to-wafer (D2W) hybrid bonding in the multilayer semiconductor manufacturing process is one of wafer direct bonding, and various studies are being conducted around the world. A noteworthy point in the current die-to-wafer process is that a lot of voids occur on the bonding surface of the die during bonding. In this study, as a suggested method for removing voids generated during the D2W hybrid bonding process, a flexible mechanism for implementing convex for die bonding to be applied to the bond head is proposed. In addition, modeling of flexible mechanisms, analysis/design/control/evaluation of static/dynamics properties are performed. The proposed system was controlled by capacitive sensor (lion precision, CPL 290), piezo actuator (P-888,91), and dSpace. This flexure mechanism implemented a working range of 200 ㎛, resolution(3σ) of 7.276nm, Inposition(3σ) of 3.503nm, settling time(2%) of 500.133ms by applying a reverse bridge type mechanism and leaf spring guide, and at the same time realized a maximum step difference of 6 ㎛ between die edge and center. The results of this study are applied to the D2W hybrid bonding process and are expected to bring about an effect of increasing semiconductor yield through void removal. In addition, it is expected that it can be utilized as a system that meets the convex variable amount required for each device by adjusting the elongation amount of the piezo actuator coupled to the flexible mechanism in a precise unit.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1142-1146
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• 2004

The ultra precision linear stage is an essential device in the fields of MEMS and Bio technology. A piezo electric motor is widely used for its better linear characteristics, faster response time, and smaller size than conventional electro-magnetic actuator. We develop a new inchworm type motor to implement an actuator-integrated a long stroke linear stage which can move fast. To implement a servo system, we use a heterodyne interferometer as a position sensor, and we propose a new measurement technique using I/Q demodulator, and we propose a counting method to measure the position of fast moving object with low cost circuitry. The characteristics of the actuator and servo system are evaluated by measuring its displacement with a commercial laser interferometer.

• 한국정밀공학회지
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• 제15권12호
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• pp.194-201
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• 1998

The beam rotating actuator has been developed. It can be utilized to improve the data transfer rate for the optical disk systems, Newly developed laser beam rotating actuator is applied to put multi-beam spots on more than one track on the optical disk simultaneously. The beam rotating actuator is made of piezoelectric ceramic bimorph as the form of cantilever, Piezoelectric actuators with high resolution, high stiffness and fast frequency response are widely assembled in micropositioning applications. Therefore, the actuator has above 50Hz natural frequency. Beam array is rotated using the dove prism in the end of beamrotator. The dynamic equation of beam rotating actuator is derived theoretically. The actuator is designed on the ground of this analysis. The performance of the beam rotating actuator is verified as the dynamics frequency performance is measured using the dynamic analyzer and sensor.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.131-134
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• 1995

The high efficiency and accuracy in machining the die material can be abtained in high speed machining, so it is necessary to analyze the mechanism of high speed cutting process : cutting force, flank wear. The tool dynomometer with high natural frequency is newly developed. With this device, the mechanism of high speed cutting process is investigated according to speed and feedate.

• 제어로봇시스템학회논문지
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• 제15권8호
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• pp.798-803
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• 2009

This paper proposes a grating scanner which is driven by a stack-type piezoelectric element. The mechanism of the grating scanner is based on flexure hinges. Using some constraints, the compliant mechanism is designed and then verified by Finite Element Analysis. The designed compliant mechanism is manufactured by wire electro-discharge machining, and then integrated with a stack-type piezoelectric element for actuation and a capacitance displacement sensor for measuring ultra-precision displacement. Experiments demonstrates the characteristics and the performances of the grating scanner using the terms of working range, resonance frequency, bandwidth and resolution. The grating scanner is applicable to a Moire interferometry for measuring 3-dimensional microscopic surface.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.743-746
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• 2002

Experimental investigation of the flow field of supersonic cavity is described. In this research, supersonic cavity is used in chemical laser system. For efficient laser, downstream flow after cavity need to be uniform and clear for pressure recovery system. In previous research, it's known that there's oscillation In cavity and is due to Mach number and L/D ratio. A strong recompression occurs at the after wall and the flow is visibly unsteady. Cavity flow in this research is of the open type, that is, length-to-depth ratio $L/D<10\;at\;M\;=\;3$. Experiment is done with pressure measurement by piezo-type sensor and visualization by Schlirern method. The time-dependent experimental result is compared with computation.