Papers by Keyword: Laser Hybrid

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Authors: Lan Tian Yang
Abstract: In this paper, a hybrid quasi-micro-pyramid structure is fabricated via nanosecond pulse laser micro-processing, which demonstrates a 15% drop in average reflectance as compared to the uniform quasi-micro-pyramid structures. The influences of laser fluence, pulse number, and designed pitch are also studied experimentally and systematically. The results show that reflection increases with the pattern pitch, decreases with pulse number, and a minimum in reflection is reached at a laser fluence of 4.83 J/cm2. The method here demonstrated provides an alternative and low-cost solution for broadband anti-reflection by hybrid structures with normal aspect ratio rather than uniform structures with high aspect ratio. Higher antireflection performance can be expected by optimizing the laser processing parameters.
Authors: Lars Erik Stridh
Abstract: Laser welding is a well known process, so is GMAW. But the joining of the processes, the so called laser hybrid welding is not that known, yet. Looking into the laser welding we realise, after many years use that there are some limitations to the process. One of the most significant is that the process deals poorly with the ability to bridge gaps between plates that are to be joined. This has its drawbacks on welding economy, the tolerances on ingoing parts has to be very high, the laser process can not tolerate more than 0,1 mm gap between the plates. The GMAW process on the other hand has the ability to deal with the joint tolerances in a better way, the backside is of course the productivity and the penetration properties. In the laser hybrid process where the two processes are joined in the same welding head, we are experienceing a great improvement in several properties. Gaps are no longer a big problem, the process can deal with gaps up to 2,0 mm with the present technology, (it is possible to coop with larger gaps using an oscillation of the laser beam, but this is only on experimental stage yet). This now means that costs for ingoing parts will be reduced. Process stability at high welding speeds is acchived. There are many advantages in high strenght steels that are sensitive to heat input; better mechanical properties are possible to obtain. Looking at the stainless materials the process has many advantages, one of the most important is the joint volume reduction in thicker materials, another is the ability to weld in duplex stainless steels.
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