Papers by Keyword: Laser Material Processing

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Authors: Yu Cao, Ting Ting Yu, Xue Lin Hu, Feng Pin Li
Abstract: A new method of parallel projection galvanometer scanning (PPGS) is presented, as a low-cost, flexible, trans-scale solution for laser material processing on freeform surfaces. The parallel projection transformation is used for mapping three-dimensional space curves to terraced two-dimensional plane graphics that each one is suitable for traditional galvanometer scanning method. For implementation of the PPGS method, a parallel projective laser scanning system with the combination of galvanometer and telecentric lens is needed, that the laser is directed along the space curve path on freeform surface part without deviation when the x-y axis galvanometer is scanning the mapping graphic path of the parallel projection plane. In practice, the existing 3D galvanometer scan system, "3+2" and rob-scan system are alternative choices in different application situations.
Authors: Aleksandr A. Kuchmizhak, Oleg B. Vitrik, Yuri N. Kulchin
Abstract: In this paper we report on the one-step fabrication of silver and gold conical microstructures using femtosecond single-pulse nanoablation. The lateral and vertical size of the microcones was found to be fully determined by the pulse energy. Using dark-field confocal microspectroscopy technique we observe and measure the resonant light scattering from the individual nanostructures in visible spectral range with the resonant peak position being dependent on the microcone size. This resonant light scattering was attributed to the excitation of the localized surface plasmon modes in the upper part of the microcones, where the main part of the molten materials accumulates and resolidifies during the formation process. The plasmon-mediated EM field enhancement near the microcones was experimentally probed and revealed by means of photoluminescent (PL) microscopy. The averaged 6-fold enhancement of the PL signal from the layer of alkylated europium complex embedded into the organic matrix was experimentally demonstrated.
Authors: Toufik Tamsaout, El Hachemi Amara
Abstract: Laser forming is a technique consisting in the design and the construction of complex metallic work pieces with special shapes difficult to achieve with the conventional techniques. By using lasers, the main advantage of the process is that it is contactless and does not require any external force. It offers also more flexibility for a lower price. This kind of processing interests the industries that use the stamping or other costly ways for prototypes such as in the aero-spatial, automotive, naval and microelectronics industries. The analytical modeling of laser forming process is often complex or impossible to achieve, since the dimensions and the mechanical properties change with the time and in the space. Therefore, the numerical approach is more suitable for laser forming modeling. Our numerical study is divided into two models, the first one is a purely thermal treatment which allows the determination of the temperature field produced by a laser pass, and the second one consists in the thermo-mechanical coupling treatment. The temperature field resulting from the first stage is used to calculate the stress field, the deformations and the bending angle of the plate.
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