• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.818-821
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• 2004

With a rapid development in the area of micro and ultra precision technology, the micro surface machining of small size parts are explosively increased. Especially, to improve efficiency of various beams in lens and reflector, non-rotational symmetric form and several mm level heights changeable surface can be machined at a time. These geometric complex 3D surface cannot be machined by general short stroke FTS. The long stroke FTS if firmly needed to move directly several mm and have nm level positioning accuracy for the complex surface form. The long stroke FTS used linear motors to drive moving unit long and fine, aero static bearings to decrease friction and moving errors in guide way, optical linear scale with nm level resolution to measure position of FTS. Furthermore, to increase the performance of acceleration of FTS, the light material, such as AL is used for the structure and the high stiffness box type structure is selected. In this paper, the genetic algorithm approach is described to determine a set of design parameters for auto tuning. The authors have attempted to model the design problem with the objective of minimizing the error, such as variable pattern change. This method can give the better alternative than existing other method.

• 한국정밀공학회지
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• 제24권11호
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• pp.52-58
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• 2007

A cutting device capable of generating various shapes of the cyclic elliptical trajectory of a cutting tool was proposed and micro v-grooving experiments were performed to investigate the characteristics of elliptical vibration cutting (EVC). The proposed cutting device is comprised of a pair of parallel piezoelectric actuators with which harmonic voltages of varying phase difference and magnitude are supplied, creating various shapes of the elliptical tool path. The attributes of the elliptical locus involving the direction of the axis of an ellipse, the rotational direction and amplitudes of a trajectory were fine-tuned for stable operation of the EVC. The EVC characteristics performed with brass and copper revealed reduction in the cutting resistance and suppression of burr formation, resulting in the enhancement of form accuracy of machined micro-features. While the effect of the EVC increases with the increase of excitation frequency and the amplitude, it is found that a change in the cutting force decreases as the amplitude of an elliptical locus increases.

• Composites Research
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• 제33권5호
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• pp.262-267
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• 2020

고속 가공과 저중량 설계에 대한 수요가 증가함에 따라, 공작기계 주축의 진동 발생 가능성이 증가하고 있다. 또한 초정밀 가공에서 주축의 진동은 공작물 표면 형상에 큰 영향을 끼치게 된다. 다양한 가공 공정의 가공 정밀도를 향상시키기 위해, 공작기계 주축 진동 문제를 해결하여야 한다. 이 논문에서, 공작기계 주축의 진동 억제를 위해 TiC-SKH51 금속 기지 복합재가 사용되었다. TiC-SKH51 복합재의 동적 특성을 확인하기 위해 충격 망치 시험을 수행하였다. FEA의 모드 분석 결과와 충격 망치 시험 결과를 비교하여 FEA의 신뢰성을 확인한 후, 공작기계 주축 모델의 해석이 실행되었다. FEA 결과로부터 진동 발생 억제를 위해 TiC-SKH51 복합재를 적용한 공작기계 주축이 사용될 수 있음을 확인하였다.

• 한국산학기술학회논문지
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• 제16권7호
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• pp.4405-4410
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• 2015

두 개의 1차원 주기 패턴을 수직으로 중첩시켜 상하층 패턴으로부터 이축 변위 정보를 각각 디코딩할 수 있는 방법을 제안한다. 투명한 상층 패턴 판별은 굴절률차에 기인한 레이저 빔의 디플렉션 검출을 통해 이뤄지고 하층 패턴 판별은 수광 전압 차의 검출를 통해 이뤄진다. 빌드 업 필름 재질의 상층 패턴은 UV 레이저 가공에 의해 미세가공되고 그리고 알루미늄 하층 패턴은 초정밀 머시닝에 의한 트렌치 가공과 불투명 소재 증착 그리고 폴리싱 과정을 통해 제작된다. 10마이크로미터 간격으로 제작된 샘플 패턴과 이를 인코딩할 수 있는 전용 광학계에 의한 변위 측정 방법은 대면적 스테이지에 장착되어 레이저 간섭계를 이용한 측정데이터와 비교하여 검증된다.

• 한국생산제조학회지
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• 제19권2호
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• pp.267-274
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• 2010

Recently, the magnetorheological (MR) polishing process has been examined as a new ultra-precision polishing technology for mirror surface generation in many applications, such as aspheric lenses, biochips, micro parts, etc. This method uses MR fluids which contains micro abrasives as a polishing media, and can. It is possible to obtain nano level surface roughness under suitable process conditions, however, required polishing time is highly dependent on the applied pre-polishing methods due to its very small material removal rate. Thus, in this study, a combined polishing method is presented to reduce total polishing time for SUS304. First, the electropolishing (EP) method was applied to obtain fine surface roughness, and the MR polishing was followed. Surface roughness variations were investigated according to the process conditions. As the results of this study, it was possible to reduce total polishing time for SUS304 using the proposed combined polishing method.

• 한국기계가공학회지
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• 제13권5호
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• pp.64-69
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• 2014

This article presents machining experiments to assess the relationship between the profile accuracy and the workpiece hardness using a natural diamond tool on an ultra-precision diamond turning machine. The study is intended to secure a corner cube prism pattern for reflective film capable of high-quality outcomes. The optical performance levels and edge images of corner cubes having various hardness levels of the copper-coated layer on a carbon steel plate are analyzed. The hardness of the workpiece has a considerable effect on the profile accuracy. The higher the hardness of the workpiece, the better the profile accuracy and the worse the edge wear of the diamond tool.

• 한국기계가공학회지
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• 제2권1호
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• pp.63-68
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• 2003

The aspherical lenses are used as objective lens of optical pickup. To examine the design factor the sample product is made before manufacturing of injection mould of lens. The optimum cutting condition of PMMA lens sample with ultra precision SPDT, the roam spindle speed, the depth of cut, the feedrate are found. The demanded surface roughness 100m Ra, aspherical form error $0.5{\mu}m$ P-V for aspherical lens of optical data storage device are satisfied.

• 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.

• 한국기계가공학회지
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• 제11권1호
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• pp.1-6
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• 2012

The polishing of silicon wafers has an important role in semiconductor manufacturing. Generally, getting a flat surface such as a mirror is the purpose of the process. The wafer surface roughness is affected by many variables such as the characteristics of the carrier head unit, operation, speed, the pad and slurry temperature. Optimum process conditions for experimental temperature, pH value, down-force, slurry ratio are investigated, time is used as a fixed factor. This study carried out a series of experiments at varying platen, chuck rpm and oscillation cpm taking particular note of the difference between the rpm and the affect it has on the surface roughness. In this experiment determine the optimum conditions for polishing silicone wafers.

• 한국기계가공학회지
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• 제7권4호
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• pp.96-101
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• 2008

Due to improve form accuracy and surface roughness of a aspheric lens core that is made of Ni, the study is carried out on localization about a Subminiature Optics of Proximity and Wide Field of View. The required form accuracy P-V $0.2{\mu}m$ and surface roughness is Ra 10 nm. The design of experiment(DOE) is adopted to find a optimal cutting conditions which are spindle speed, depth of cut, feedrate. Finally, the effects of this study are replacing importation and strengthening competitiveness through the localization of the Subminiature Optics of Proximity and Wide Field of View.