• 제목/요약/키워드: Laser materials processing

검색결과 400건 처리시간 0.023초

Laser decontamination for radioactive contaminated metal surface: A review

  • Qian Wang;Feisen Wang;Chuang Cai;Hui Chen;Fei Ji;Chen Yong;Dasong Liao
    • Nuclear Engineering and Technology
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    • 제55권1호
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    • pp.12-24
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    • 2023
  • With the improvement of laser technology, the strategic needs of efficient and precise decontamination of various components in nuclear application units can be fulfilled by laser decontamination. The surface contaminants of nuclear facilities mainly exist both as loose contaminated layer and fixed oxide layer. The types of radionuclides and contamination layer thickness are closely related to the operation status of nuclear facilities, which have an important influence on the laser decontamination process. This study reviewed the mechanism of laser surface treatment and the influence of laser process parameters on the decontamination thickness, decontamination factor, decontamination efficiency and the distribution of aerosol particle. Although multiple studies have been performed on the mechanism of laser processing and laser decontamination process, there are few studies on the microscopic process mechanism of laser decontamination and the influence of laser decontamination on surface properties. In particular, the interaction between laser and radioactive contaminants needs more research in the future.

펨토초 레이저에 의한 크롬박막 미세 회절패턴 제작 (Diffractive patterning on Cr thin film using femtosecond laser pulses)

  • 김재구;조성학;장원석;나석주;황경현
    • 한국레이저가공학회지
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    • 제10권4호
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    • pp.18-22
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    • 2007
  • In this paper, we suggested the femtosecond laser processing using the mask which makes Gaussian spatial beam distribution to a normalized distribution by Fresenel diffraction. Holography pattern of the size of $320{\times}320{\mu}m^2$ on the Cr thin film on glass substrate with a pixel size of $5{\times}5{\mu}m^2$ was fabricated according to the pattern generated by the iterative Fourier transform algorithm(IFTA) algorithm. We analysed the damage threshold with an assumption the power distribution as Gaussian profile as 45 $mJ/cm^2$. The regenerated image of letters through the diffractive pattern was well recognized at the screen.

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Two-dimensional Laser Drilling Using the Superposition of Orthogonally Polarized Images from Two Computer-generated Holograms

  • Lee, Hwihyeong;Cha, Seongwoo;Ahn, Hee Kyung;Kong, Hong Jin
    • Current Optics and Photonics
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    • 제3권5호
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    • pp.451-457
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    • 2019
  • Laser processing using holograms can greatly improve processing speed, by spatially distributing the laser energy on the target material. However, it is difficult to reconstruct an image with arrays of closely spaced spots for laser processing, because the specklelike interference pattern prevents the spots from getting close to each other. To resolve this problem, a line target was divided in two, reconstructed with orthogonally polarized beams, and then superposed. Their optical reconstruction was performed by computer-generated holograms and a pulsed laser. With this method, we performed two-dimensional (2D) laser drilling of polyimide film, with a kerf width of $20{\mu}m$ and a total processing length of 20 mm.

저탄소강 SS41 연속파형 Nd:YAG 레이저 겹치기 용접의 기공제어 기술 (The Porosity Control Technology of Lap Joint Welding Using Continuous Wave Nd:YAG Laser of the Low Carbon Steel SS41)

  • 이가람;황찬연;양윤석;박은경;유영태
    • 한국생산제조학회지
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    • 제22권4호
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    • pp.665-672
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    • 2013
  • With the development of advanced processing technology, laser processing systems, which require high-quality precision processing, have attracted considerable attention. Although laser equipment is expensive, it enables quick processing and less deformation of materials. This technology is often applied to secondary batteries, which has thus farinvolved the use of argon tungsten inert gas (TIG) welding. However, the welding characteristics of argon TIG welding are not yet good, and a laser is used for welding to address this problem. In this study, lap-joint welding was conducted, and the desired welding characteristics were obtained when the laser power was 1800W and the laser beam travel speed was 1.8 m/min. Lap-joint welding was conducted on Ni-coated SS41. Two cases were compared. No pores were observed in the Ni-coated SS41 lap-joint welding part, and cracks appeared from the lap-joints. Moreover, the pole rod and tap were welded together in a T-joint form to improve the output of the secondary battery. T-joint laser welding showed better welding characteristics than TIG welding.

도트 패턴을 이용한 회절 격자 금형 제작 (Fabrication of diffraction grating mold using dot pattern)

  • 노지환;이제훈;손현기;서정;신동식;정용운
    • 한국레이저가공학회:학술대회논문집
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    • 한국레이저가공학회 2006년도 추계학술발표대회 논문집
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    • pp.114-117
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    • 2006
  • Diffraction grating is the optical device which has periodic pattern. Decorative logotypes is the one of application of diffraction grating. In this paper diffraction grating for decorative logotype is fabricated by dot pattern in stead of line pattern. A metallic mold for diffraction gratings is fabricated with a mode-locked 12 ps $Nd:YVO_4$ laser. Laser pulses with a wavelength of 355nm are irradiated on the surface of NOK 80, a mold material, to generate dot patterns. In order to minimize the dot diameter, laser power is set just above the ablation threshold of NOK 80. Results show that the spectrum from the fabricated mold is good enough for some industrial application.

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선택적 레이저 용융공정으로 제조된 Al-Si-Mg 합금의 열처리에 따른 미세조직 및 특성평가 (Microstructures and Characterization of Al-Si-Mg Alloy Processed by Selective Laser Melting with Post-Heat-treatment)

  • 이기승;엄영성;김경태;김병기;유지훈
    • 한국분말재료학회지
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    • 제26권2호
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    • pp.138-145
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    • 2019
  • In this study, Al-Si-Mg alloys are additively manufactured using a selective laser melting (SLM) process from AlSi10Mg powders prepared from a gas-atomization process. The processing parameters such as laser scan speed and laser power are investigated for 3D printing of Al-Si-Mg alloys. The laser scan speeds vary from 100 to 2000 mm/s at the laser power of 180 and 270 W, respectively, to achieve optimized densification of the Al-Si-Mg alloy. It is observed that the relative density of the Al-Si-Mg alloy reaches a peak value of 99% at 1600 mm/s for 180 W and at 2000 mm/s for 270W. The surface morphologies of the both Al-Si-Mg alloy samples at these conditions show significantly reduced porosities compared to those of other samples. The increase in hardness of as-built Al-Si-Mg alloy with increasing scan speed and laser power is analyzed due to high relative density. Furthermore, it was found that cooling conditions after the heat-treatment for homogenization results in the change of dispersion status of Si phases in the Al-Si matrix but also affects tensile behaviors of Al-Si-Mg alloys. These results indicate that combination between SLM processing parameters and post-heat treatment should be considered a key factor to achieve optimized Al-Si alloy performance.

로봇 기반 원격 레이저 용접에 관한 연구 (Study on Robot based Remote Laser Welding)

  • 강희신;서정;조택동
    • 한국레이저가공학회지
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    • 제11권4호
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    • pp.21-28
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    • 2008
  • Remote Laser welding technology for manufacturing automotive body is studied. Laser welding and industrial robot systems are used for the robot based laser welding system. The laser system is used 1.6kW Fiber laser(YLR-1600) of IPG. The robot system is used HX130-02 of Hyundai Heavy Industry(payload : 130kg). The robot based laser welding system is equipped with laser scanner system for remote laser welding. The welding joints of steel plate and steel plate coated with zinc are butt and lapped joints. The quality test of the laser welding are through the observation the shape of bead on plate and cross-section of welding part. During past three years the laser system, 4kW Nd:YAG laser (HL4006D) of Trumpf was used and the robot system, IRB6400R of ABB (payload:120kg) was used. The new laser source, robot and laser scanner system are used to increase the processing speed and to improve the process efficiency. This paper introduces the robot based remote laser welding system to resolve the limited welding speed and accuracy of the conventional laser welding system.

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Space-selective Precipitation and Control of Functional Crystals in Glasses by a Femtosecond Laser

  • Qiu, Jianrong;Zhu, Bin;Dai, Ye
    • 세라미스트
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    • 제10권3호
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    • pp.91-97
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    • 2007
  • Femtosecond laser micro-processing received much attention in the past decade. The nature of ultra-short light-matter interaction permits femtosecond laser to overcome the diffraction limit and realize precise micro-processing. The ultrahigh light intensity of the femtosecond laser allows sapece-selective microscopic modifications to materials based on multiphoton processes. In this paper, we review our recent research development on space-selective precipitation and control of functional crystals in glasses by an infrared femtosecond laser. The technique will open new possibilities in the fabrication of micro-optical components with various optical functions.

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OPTIMAL PROCESSING AND SYSTEM MANUFACTURING OF A LASER WELDED TUBE FOR AN AUTOMOBILE BUMPER BEAM

  • Suh, J.;Lee, J.H.;Kang, H.S.;Park, K.T.;Kim, J.S.;Lee, M.Y.;Jung, B.H.
    • International Journal of Automotive Technology
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    • 제7권2호
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    • pp.209-216
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    • 2006
  • A study has been conducted for an optimal processing and an apparatus for manufacturing a laser welded tube for one-body formed bumper beam. The tube dimensions used in calculation were the thickness of 1.4 mm, the diameter of 105.4 mm and the length of 2000 mm. The tube was formed of a cold rolled high strength steel plate(tensile strength of 600 MPa). The two-roll bending method was the optimal tube forming process in comparison with the UO-bending method, the bending method on the press brake, the multi-step continuous roll-forming method and the 3-roll bending method. Monitoring of the welding quality was conducted and the seam tracking along the butt-joint lengthwise to the tube axis was also examined. The longitudinal butt-joint was welded by using a $CO_2$ laser welding machine equipped with a seam tracker and a plasma sensor. The $CO_2$ laser tube welding machine could be used for precise seam tracking and real-time monitoring of the welding quality. As a result, the developed laser welded tube could be used for a one-body formed automobile bumper beam.

펨토초 레이저 유도 나노 및 마이크로 구조물을 활용한 금속 표면 기능성 제어 (Controlled Surface Functionalities of metals using Femtosecond Laser-induced Nano- and Micro-scale Surface Structures)

  • 박태훈;이효수;이해중;황택용
    • Design & Manufacturing
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    • 제17권2호
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    • pp.55-61
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    • 2023
  • With femtosecond (fs) laser pulse irradiation on metals, various types of nano- and micro-scale structures can be naturally induced at the surface through laser-matter interaction. Two notable structures are laser-induced periodic surface structures (LIPSSs) and cone/spike structures, which are known to significantly modify the optical and physical properties of metal surfaces. In this work, we irradiate fs laser pulses onto various types of metals, cold-rolled steel, pickled & oiled steel, Fe-18Cr-8Ni alloy, Zn-Mg-Al alloy coated steel, and pure Cu which can be useful for precise molding and imprinting processes, and adjust the morphological profiles of LIPSSs and cone/spike structures for clear structural coloration and a larger range of surface wettability control, respectively, by changing the fluence of laser and the speed of raster scan. The periods of LIPSSs on metals used in our experiments are nearly independent of laser fluence. Accordingly, the structural coloration of the surface with LIPSSs can be optimized with the morphological profile of LIPSSs, controlled only by the speed of the raster scan once the laser fluence is determined for each metal sample. However, different from LIPSSs, we demonstrate that the morphological profiles of the cone/spike structures, including their size, shape, and density, can be manipulated with both the laser fluence and the raster scan speed to increase a change in the contact angle. By injection molding and imprinting processes, it is expected that fs laser-induced surface structures on metals can be replicated to the plastic surfaces and potentially beneficial to control the optical and wetting properties of the surface of injection molded and imprinted products.