• Proceedings of the Korean Society of Laser Processing Conference
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• 2004.10a
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• pp.68-72
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• 2004

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.299-300
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.565-566
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.417-418
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.655-656
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.609-610
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• 2011

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.613-614
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• 2011

• Korean Journal of Optics and Photonics
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• v.7 no.3
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• pp.232-237
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• 1996

A 500 Hz repetition rate excimer laser was developed as light source for pollution lidar. In this paper, the high repetitive output characteristics, the gas flow loop structure, and CR(clearing ratio) characteristics were investigated. Our laser system was constructed compact structure with a streamline gas flow loop and UV preionization. The real gas volume of laser is 10 liter. At 500 Hz repetitive operation, we have obtained average power of 53 watt with KrF laser gas. The variation of laser output, CR, and active volume are $\pm$6.7%, 2.3, and 2.0(H)$\times$1.2(W)$\times$56(L)=134 ㎤, respectively. Laser output power is declined to half at 3$\times$$10^6$ shots.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.62-67
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• 2012

Recently UV laser is widely used to process micro parts using various materials such as polymers, metals and ceramics because it has a very high intensity at the focused spot area. It is generally known that there are still some difficulties for alumina($Al_2O_3$) ceramics to directly make micro patterns like holes and lines on the surface of working material using 355nm UV laser because the alumina has a very low absorption coefficient at that wavelength. But nowadays new alumna with nano-porous holes is developed and applied to advanced micro functional parts of IT, BT and BT industries. In this paper, we are going to show the mechanism of photo-thermal ablation for nano-porous ceramics. Inside hole there is a lot of multiple reflections along the depth of hole. Experimentally we can find the micro hole drilling and micro grooving on the surface of nano-porous alumina.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.6
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• pp.89-94
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• 2016

Consumer orientation requires that companies understand consumer needs and produce products that meet their expectations. This study proposes a new additive method that creates a polymer/metal bonding layer and thus can lighten the weight of helmets to develop a consumer-oriented 3D printing helmet. The composite solution is experimentally prepared with copper formate and a photopolymer resin. Stereolithography apparatus and photothermal reactions are introduced to fabricate an adhesive hybrid layer of copper metal and polymer. A UV pulse laser with a 355 nm wavelength was installed to simplify this process. Resistance, adhesion, and accuracy were investigated to evaluate the properties of the layer produced.