The high power multimode fiber-coupled laser sources, like solid state lasers or laser diodes as well as single mode and multimode fiber lasers, are now widely used in various industrial laser material processing technologies like metal or plastics welding, cladding, hardening, brazing, annealing. Performance of these technologies can be essentially improved by varying the irradiance profile of...

Femtosecond laser pulses were focused on the interface of two glass specimens. Proper use of optical and laser processing parameters enables transmission welding. The morphology of the weld cross section was studied using differential interference contrast optical microscopy. The changes in mechanical properties of the weld seams were studied through spatially resolved nanoindentation, and inde...

Amodel based on a double-ellipsoidal volumeheat source to simulate the gasmetal arcwelding (GMAW) heat input and a cylindrical volume heat source to simulate the laser beam heat input was developed to predict the temperature field and thermally induced residual stress in the hybrid laser–gas metal arc (GMA) welding process. Numerical simulation shows that higher residual stress is distributed i...

This paper was aimed to report the 3D finite element analysis simulation of laser welding process of Ti6Al4V 1.7 mm sheets in butt joint in order to predict the temperature distribution, hardness, and weld geometry. The butt-joint welds were made using CO2 laser with the maximum power of 2.2 kW in the continuous wave mode. A part of the experimental work was carried out to verify the weld geome...

Laser welding has been widely used in various industry fields. In order to further alter and broaden its applicability, a novel technology of laser welding under vacuum is introduced. The combination of high power laser and low ambient pressure provides an excellent welding performance and quality. In this paper, an overview on laser welding under vacuum is presented. It begins with a short int...

in the present study, an ultrafine grained (ufg) 304l stainless steel with the average grain size of 300 nm was produced by a combination of cold rolling and annealing. weldability of the ufg sample was studied by nd: yag laser welding under different welding conditions. taguchi experimental design was used to optimize the effect of frequency, welding time, laser current and laser pulse duratio...

In macro welding-processes, monitoring and closed-loop control by using the so-called “full penetration hole” is well known. This paper reports first results for the transfer of this technology to laser micro-welding processes for lap joints as they are used for housings or fuel cells. The laser source was a 400 W cw fiber laser with a Gaussian beam profile and a spot size of 28 μm. A cellular ...

Although lasers are widely used for welding in precision engineering industry, it is still a challenge to achieve high accuracy in creating and positioning welding spots at extremely high processing speed. Towards this end, we propose a system for monitoring the welding process in order to ensure good quality of the welding spots. Our technology enables high speed image acquisition confocally t...