• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.06a
• /
• pp.461-462
• /
• 2009

• Journal of the Korean Society for Nondestructive Testing
• /
• v.27 no.2
• /
• pp.183-189
• /
• 2007

Ultra precise processed parts are required together with the development of optoelectronics industry. As important parts of optoelectronics industry, there are ferrule of optical connector and lens for optical devices. In particular, the lens requires high reliability with high precision without including flaws. These optical modules need ultra precise processing in order to reduce the loss of light sources and various nondestructive inspections are carried out in the finishing stage to separate good and bad quality products. Therefore, it was analyzed through the characteristics of response of amplitude and resonant frequency according to the mass variations of aspheric lens that is used currently in laser printers.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.11 no.3
• /
• pp.7-12
• /
• 2012

Ceramic core processing technology using 5-axis high-speed cutting machine is applied to make the glass molds for aspherical ophthalmic lenses. In the technology, optimum processing conditions for aspherical ceramic molds are based on minimal experimental data of surface roughness. Such surface roughness is influenced by fabricating tools, cutting speed, feed rate, and depth of cut, respectively. In this paper, we present that surface roughness and shape accuracy of aspheric ceramic mold obtained by optimum processing conditions are Pa $0.6184{\mu}m$ and Pt $5.0301{\mu}m$, respectively, and propose that these values are sufficiently possible to apply to making the glass molds for aspherical ophthalmic lenses.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.15-18
• /
• 2005

As consumer in optics, electronics, aerospace and electronics industry grow, the demand for ultra-precision aspheric surface lens increases higher. To enhance the precision and productivity of ultra precision aspheric surface micro lens, The development of ultra-precision grinding system and manufacturing properties for the aspheric surface micro lens are described. In the work reported in this paper, and ultra-precision grinding system for manufacturing the aspheric surface micro lens was developed by considering the factors affecting the surface roughness and profiles accuracy. And this paper deals with mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and spherical lens of BK7. It results was that a form accuracy of $3\;{\mu}m$ P-V and a surface roughness of $0.1\;{\mu}m\;R_{max}$.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.4
• /
• pp.129-134
• /
• 2000

This paper presents the development of ultra-precision machining process of large aspheric aluminum mirrors with a maximum diameter of 620 mm. An ultra-precision machine, "Nanoturn60", developed by Daewoo Heavy Industries Ltd. is used for machining and motion errors of the machine are compensated by using the FTS developed by IAE(Institue for Advanced Engineering) during the machining process. To check the form accuracy of machined aspheric surfaces, on-machine form measurement system is developed. This measurement system consists of air bearing touch probe, straight edge, and laser sensor. With in-process error compensation by FTS(Fast Tool Servo), aspheric mirrors with the from accuracy of submicron order are obtained. obtained.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.1469-1474
• /
• 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 Tribologists and Lubrication Engineers Conference
• /
• 1990.06a
• /
• pp.45-52
• /
• 1990

고도의 신뢰도를 요구하는 정밀기계의 보편화는 트라이볼로지 요소중에서 밀봉기능에 관련된 시일의 해석 및 설계가 커다란 관심사로 부각되었다. 특히 고속회전을 요하는 경우에 대한 회전 시스템의 동적 안정성은 대단히 중요하다. 미끄럼 접촉운동을 하고 있는 기계평면시일의 시일링 간극은 대단히 작기 때문에 시일의 접촉면에서 형상이 변화하게 되면 시일 성능은 커다란 영향을 받게 된다. 시일의 접촉표면 가공시 발생되는 평면도(flatness), 조립시의 회전축과 시일축 사이의 중심 맞추기의 어려움, 회전축의 자중량 등 때문에 발생되는 회전링 사이의 상대적인 경사도(misalignment)는 시일의 동적 불안정성에 영향을 준다. 또한 상대 접촉 운동면에서 경계 또는 고체 마찰에 의한 마멸의 진행은 시일의 코닝(coning) 현상을 일으킨다. 본 연구에서는 비압축성 유체가 온도의 영향을 받아 점도가 선형적으로 변화하는 경우에 대한 시일링 간극 내에서의 압력분포를 유한차분법을 이용하여 해석하였다. 여기서 얻어진 결과를 이용하여 시일의 축력과 모우멘트를 해석함으로써 시일의 동적 불안정성에 대하여 논하였다. 이 때 기계평면 시일의 형상은 코닝이 있고, 시일의 중심축이 경사진 경우를 고려하였다.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.15 no.2
• /
• pp.1-9
• /
• 2006

As consumers in optics, electronics, aerospace and electronics industry grow, the demand for ultra-precision aspheric surface lens increases higher. To enhance the precision and productivity of ultra precision aspheric surface micro lens, the development of ultra-precision grinding system and process for the aspheric surface micro lens are described. In the work reported in this paper, an ultra-precision grinding system for manufacturing the aspheric surface micro lens was developed by considering the factors affecting the ground surface roughness and profile accuracy. This paper deals with mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and spherical lens of BK7. The optimization of grinding conditions on ground surface roughness and profiles accuracy is investigated using the design of experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.561-562
• /
• 2006

To enhance the precision and productivity of ultra precision aspheric surface micro lens, the development of ultra-precision grinding system and process for the aspheric surface micro lens are described. In the work reported in this paper, an ultra-precision grinding system for manufacturing the aspheric surface micro lens was developed by considering the factors affecting the grinding surface roughness and profile accuracy. This paper deals with mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and spherical lens of BK7. The optimization of grinding conditions on ground surface roughness and profiles accuracy is investigated using the design of experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.04b
• /
• pp.23-27
• /
• 1993

스테인리스강은 내식성, 내열성, 내산화성이 좋으므로 화학산업, 의학용기, 고정밀 산업 등에서 많이 사용되고 있다. 스테인리스강은 열전도율이 낮고 용융물의 점성이 크고 가공경화가 심하기 때문에 인코넬 티탄합금 등과 함께 난삭재로 알려져 있다. 스테인리스강의 고합금강을 사용한 기계가공은 공구의 마모가 심하게 일어나므로 가 공이 어렵다. 화염절단(Flame dutting)도 합금물의 버닝(burning)현상을 막는 성질 때문에 잘쓰이지 않고 플라 즈마-아크(plasma-arc) 절단은 수중에서 이루어질 경우 절단끝이 산화되지 않는 좋은 절단면을 얻을 수 있으나 수중에서 사용해야 하는 어려움이 있다. 레이저를 이용한 가공은 절단폭이 작아 재료의 손실이 적으며 복잡한 형상의 절단도쉽고 공구의손실이 없는등 많은 장점이 있어서 사용이 증가하고 있다. 본 연구에서는 스테인리스 강의 절단메커니즘에대한 이해를 돕기 위해 절단가공에 큰 영향을 끼치는 레이저 출력, 절단속도, 절단가스의 압력, 재질, 절단두께를 절단변수로채택하여 절단을 수행하였다. 절단결과를 비교 검토하여 절단변수가 절단에 미치는 영향을 분석하였고 최적의 절단을 얻는 가공조건을 제시하였다.