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금과 니켈이 코팅된 베릴륨 구리에 다른 반복율을 적용한 레이저 드릴링 공정의 실험적 연구
손승익(Seungik Son),이동경(Dongkyoung Lee) 대한용접·접합학회 2019 대한용접·접합학회지 Vol.37 No.3
Due to the development of technology and high-tech industrialization, various processing technologies requiring precision are developed and the high degree of precision is further required. Therefore, laser-aided manufacturing has been applied in many engineering fields due to many advantages. However, without understanding fundamental interaction characteristics, its advantages cannot be fully utilized. In this study, the interaction between laser and material is investigated by laser process applied with the different repetition. The wavelength of IR laser used in this experiment is 1064nm. the parameters of IR laser are laser power (20 W), repetition rate (105 kHz, 200 kHz), pulse duration (20 ns) and these parameters are constant during the laser drilling. In addition, the experiment is performed by increasing the laser total energy. For the component analysis of specimen and result of experiment, we use scanning electron microscope (SEM) and energy dispersive X-ray (EDX). And then the result of the Heat affected zone, Material removal zone and Burr is measured. Through this study, it seems that the interaction characteristic is controlled by repetition rate.
Experimental Study of Electrode Structuring using Nanosecond Laser for Enhanced Battery Performance
Dongkyu Park(박동규),Dongkyoung Lee(이동경) 대한용접·접합학회 2020 대한용접·접합학회지 Vol.38 No.5
Currently, alternative energy sources are attracting attention owing to environmental pollution and the depletion of fossil fuels. Lithium-ion batteries have a light weight, high energy density, high power density, and long cycle life, making them attractive alternative energy sources. Numerous studies have been conducted on high-performance batteries. However, most studies have focused on improving active material characteristics. Thus, there is a lack of research on battery performance enhancement through the improvement of the battery manufacturing process. In this study, we performed electrode structuring using a nanosecond laser in the power range of 1 W to 19 W (2 W intervals). The geometric changes after laser structuring were observed using a scanning electron microscope, and the electrode geometries were classified and measured in terms of ablation width and depth. The aspect ratio, removal amount, and removal rate of the active material were analyzed after laser structuring. A maximum aspect ratio of 0.77 was achieved. Additionally, the removal amount and removal rate of the active material increased with the increase in laser power. Therefore, we concluded that electrode geometry can be controlled using a nanosecond laser.
아크 용접 후 용접 비드 주변에 형성된 부산물을 제거하기 위한 나노초 레이저 클리닝
서영진(Youngjin Seo),이동경(Dongkyoung Lee) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
Welding process is an essential process, but the formation of by-products including slag, oxide, and heat tint after welding adversely affect the corrosion resistance and painting performance of the products. The chemical cleaning generates environmental pollution, and the mechanical method is limited due to the difficulty to access curved geometry of the workpiece. However, laser cleaning can overcome these problems. Especially, this technique can remove the welding by-products with no critical damage on the surface and secondary waste is barely formed during processing. To analyze the interaction characteristics between laser and material, different laser parameters are set. The microstructure and chemical composition are observed using SEM/EDX, respectively. Consequently, when the laser power increases, the oxygen component on the surface decrease because the heat tint and oxide layer are removed. Also, when the scanning speed decreases, the over-cleaning is generated on the surface and the surface of the substrate is damaged.