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| 3. |
- Bergström, David, et al.
(författare)
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Mathematical Modelling of Laser Absorption Mechanisms in Metals: A Review
- 2003
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Ingår i: M4PL16 - 16th Meeting on Mathematical Modelling of Materials Processing with Lasers.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In Laser Material Processing, an understanding of the fundamental absorption mechanisms plays a vital role in determining the optimum processing parameters and conditions. To this end, a combination of experimental as well as of theoretical work is required. In this paper, results of some of the most important mathematical models of laser-metal interactions are reviewed, including models for absorptivity dependence on wavelength, polarization, angle of incidence, workpiece temperature, surface roughness, defects, impurities and oxides.
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| 4. |
- Engström, Hans, et al.
(författare)
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Adaptive process control in laser robotic welding
- 2003
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Ingår i: 9th NOLAMP Conference. - Trondheim : Department of Geography, Norwegian University of Science and Technology. - 8292499016 ; , s. 251-258
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Konferensbidrag (refereegranskat)abstract
- An adaptive process control and seam tracking system for robotic laser welding with filler was developed and then evaluated for the butt welding of SS-1147 mild steel sheets of thickness 2 mm. The system comprises a 3 kW Nd:YAG laser, an industrial robot and a laser camera for seam tracking and measurement of gap width. The gap width data are used to control welding speed and wire feed rate. Experiments were carried out to weld butt joints of SS-1147 mild steel with gap widths varying between 0-0.8 mm. The resultant weld geometry was evaluated to determine the operating range of the laser camera (measured gap width) for monitoring to result in acceptable welds.
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| 5. |
- Forsman, Tomas, et al.
(författare)
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Initiation and termination phenomena in laser welding of aluminum
- 2000
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Ingår i: Journal of laser applications. - : Laser Institute of America. - 1042-346X .- 1938-1387. ; 12:2, s. 81-84
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Tidskriftsartikel (refereegranskat)abstract
- This article investigates a defect problem related to laser welding of tailored aluminum blanks. During the initial few millimeters of welding the weld was intermittent. By applying an analytical line source model the weld was shown to experience overheating close to the starting edge. This overheating was reduced by ramping the power during the initial 100 mm and this made the defects disappear. Al sheets of 0.1mm thickness with milled edges were butt welded and bead-on-plate welded in the present investigation.
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| 6. |
- Gedda, Hans, et al.
(författare)
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A process efficiency comparison of Nd:YAG and CO2 laser cladding
- 2002
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Ingår i: Welding in the World. - 0043-2288 .- 1878-6669. ; 46:spec, s. 75-86
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Tidskriftsartikel (refereegranskat)abstract
- Blown powder laser cladding is a cost effective way of producing a surface layer to withstand wear and corrosion. However, the cladding process is slow. Therefore is it of great interest to investigate how much of the laser power is used in the cladding process and how much is reflected etc. In this investigation an Nd:YAG and a CO2-laser have been compared as energy sources for the process. Every aspect of the energy redistribution during cladding has been analysed. The main energy loss to the process for both lasers is by reflection from the melt pool and the powder cloud. It was found that the Nd: YAG laser cladding process is approximately twice as energy efficient as the CO2 laser cladding process
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| 8. |
- Gedda, Hans, et al.
(författare)
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Development of the laser clad casting techniques
- 2003
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Ingår i: 9th NOLAMP Conference. - Trondheim : Department of Geography, Norwegian University of Science and Technology. - 8292499016 ; , s. 137-148
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Konferensbidrag (refereegranskat)
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| 9. |
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| 10. |
- Gedda, Hans, et al.
(författare)
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Laser cladding into pre-machining groves
- 2004
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Ingår i: Peer reviewed conference proceedings. - Orlando, Fla. : Laser institute of America. - 0912035765 ; , s. 18-23
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Konferensbidrag (refereegranskat)abstract
- When laser cladding is used to improve the wear characteristics of a substrate it is not always necessary to clad the whole surface. Wear resistant individual tracks can be clad directly onto the substrate or into pre machined grooves. This paper investigates the process parameters which affect the finished product when cladding into groves including; groove geometry, powder application method and laser type
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