• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.446-449
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• 1995

In this paper, the accurate end position control method of ultraprecision machine tool post using piezoelectric material as an micro positonong devics is presented. This method employs the classical PID feedback and uses an additional notch filter which eliminates the resonance characteristics of controlled plant. And the simple predictor is added to make use of the future value of desired input for better tracking performance. To show the feasibilty of proposed method, the PC-based experimental apparacy can be obtained. Using method, Al specimen of diameter 100mm was cut under practical machining condition to test the practicability of proposed method.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1469-1474
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• 2007

In recent years, research to machine large-surface micro-features has become important because of the light guide panel of a large-scale liquid crystal display and the bipolar plate of a high-capacity proton exchange membrane fuel cell. In this study, in order to realize the systematic design technology and performance improvements of an ultra-precision machine for machining the large-surface micro-features, a structural characteristic analysis was performed using its virtual prototype. The prototype consisted of gantry-type frame, hydrostatic feed mechanisms, linear motors, brushless DC servo motor, counterbalance mechanism, and so on. The loop stiffness was estimated from the relative displacement between the tool post and C-axis table, which was caused by a cutting force. Especially, the causes of structural stiffness deterioration were identified through the structural deformation analysis of sub-models.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.627-628
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• 2010

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.12
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• pp.1173-1179
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• 2007

In recent years, research to machine large-surface micro-features has become important because of the light guide panel of a large-scale liquid crystal display and the bipolar plate of a high-capacity proton exchange membrane fuel cell. In this study, in order to realize the systematic design technology and performance improvements of an ultra-precision machine for machining the large-surface micro-features, a structural characteristic analysis was performed using its virtual prototype. The prototype consisted of gantry-type frame, hydrostatic feed mechanisms, linear motors, brushless DC servo motor, counterbalance mechanism, and so on. The loop stiffness was estimated from the relative displacement between the tool post and C-axis table, which was caused by a cutting force. Especially, the causes of structural stiffness deterioration were identified through the structural deformation analysis of sub-models.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.283-286
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• 2002

This paper presents the straightness compensation system which is a device for improving the machining accuracy of ultra-precision machines by synchronizing the position of diamond tool tip with machine error motion. Sine it is actuated by piezoelectric actuator with highly nonlinear hysteresis characteristics, the feedback control schemes such as Proportional Integral(PI), are required and realized by measuring the displacements of diamond tool tip. for the better tracking performance, the controller was implemented using TMS320C32 32bit floating-point DSP which is fast so that the real-time control is possible. In addition, stand alone type DSP board was chosen fur the easy assembly into the ultra-precision machines. The experimental results show good command tracking performance and the motion error of the machine is satisfactorily compensated during the machining process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.86-93
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• 2005

In this paper, we discuss the merits of mechanical machining to generate micro features on large surfaces. An overseas technology trend related to the micro machining and dedicated machinery is also presented. We provide an overview of what characteristics the machinery is required to have to generate micro features on large surfaces and what kind of technical barriers need to be overcome to put the technology to practical use.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.3
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• pp.29-35
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• 2006

Various types of elliptical motions are generated by PZT mechanism which is composed of two parallel piezoelectric actuators. Elliptical vibration cutting(EVC) is obtained by attaching single crystal diamond cutting tool to the mechanism, and V-grooving for Brass and Aluminum is carried out by applying the EVC. It is experimentally observed that the cutting force in the process of the EVC reduces compared to the ordinary non-vibration cutting, which is due to the decrease of undeformed chip thickness and frictional force between the tool and chip. Ultrasonic elliptical vibration cutting(UEVC) suppresses burr formation and decreases cutting force still more, so UEVC makes it possible to enhance the shape accuracy of machined surface.

• 기계와재료
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• v.22 no.1
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• pp.14-21
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• 2010

초미세 레이저 가공기술은 미세화, 대면적화, 고속화의 방향으로 발전되고 있다. 이에 따라 이를 대응한 레이저의 사양도 파장의 단파장화 또는 펄스폭의 극초단화, 펄스 반복률의 고반복률화, 출력의 고출력화가 요구되고 있다. 극초단 펄스레이저는 사용자 편의성, 안정성 측면에서 산업체의 요구에 미흡하다. 이에 따라 산업용 초미세 레이저 가공을 위한 광원으로 고품질, 고출력의 단파장 자외선 레이저 활용에 집중하고 있다. 현재 고품질 자외선 레이지는 DPSSL 형태로 구성되어 출시되고 있고, 거의 대부분 수입에 의존하고 있다. 국내외 자외선 UV 현황을 간단히 기술하고, 광주과기원 고등광기술연구소에서 산업원천기술개발사업의 일환으로 개발중인 복합형 자외선 DPSSL에 대한 개발 계획 레이저 특성과 현재의 개발 진행 상황을 소개한다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1495-1508
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• 1990

There are requirement of surface roughness in mechanical elements that has minute surface of several nm degree. When high precision surface roughness measurement is made with stylus type surface roughness measuring apparatus, measuring accuracy depend on the tip radius of diamond stylus. Therefore, ultra precision machining was accomplished using ion sputter machining in order to machining the stylus tip radius less than 0.5.mu.m, which is impossible through lapping machining. In this study, optimal machining condition for the ion sputter machining was obtained through the experiment under the various varing machinbing quantity and condition of diamond stylus. And as the result of applying this optimal condition, the good result was obtained that machining probability of stylus tip radius less than o.5.mu.m is 93%.

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