Modeling of the melted bath movement induced by the vapor flow in deep penetration laser welding

Abstract

In this article we are interested in a moving mechanism occurring in the melted bath that is produced during the deep penetration laser welding process. It concerns the displacement of the melted metal induced by the friction effect due to the interaction with the metallic vapor when it flows toward the keyhole exit. Boundary conditions resulting from a ray-tracing procedure are used in the numerical solving of the unsteady Navier–Stokes conservation equation for both liquid and gaseous phases. The melted metal is considered for the liquid phase, whereas the metallic vapor and the environing air are taken as gaseous phases. The volume of fluid approach used in our modeling allows the tracking of the vapor–liquid wall interface evolution. We will present sequences of the melted bath profiles evolution as the vapor flows and interacts with it. An estimation of the velocity of the displaced liquid boundary layer allows a comparison with experimental results concerning the expelled melted metal velocity.

Developments in Nd:YAG laser welding

“…The dynamic behaviour of these bubbles, whether or not it leads to porosity formation, has been remarkably demonstrated by the various X-ray shadowgraphy experiments realized by the Osaka team (Katayama, 2010) for the last 20 years and also more recently at IFSW in Stuttgart (Abt et al, 2011). Also, some rather recent 2D and 3D numerical simulations have been able to reproduce the complex mechanisms of the interaction of the vapour plume with the melt pool (Amara et al, 2006;Amara and Fabbro, 2008;L. Zhang et al, 2011).…”

Dual Control for Jerk-Driven Robotics in Rehabilitative Planar Applications

“…In this way, the system may also support the user when the resultant capacity is not sufficient to reach the target point or to reach the correct direction when the reference trajectory is not satisfied. Finally, the actuators are regulated by a torque-based control, which manages the required forces to satisfy the trajectory of the active DOFs [20][21][22][23][24][25]. The aim is to determine the nominal torque H d and the reference path for ϕ p , denoted ϕ d,p , so that ϕ d,T satisfies the motion equations in (6).…”

Basic Mechanism of Surface Topography Evolution in Electron Beam Based Additive Manufacturing

“…In contrast, excessive energy input above the high energy boundary of the classic process window leads to pronounced material transport and results in an uneven melt surface topography [ 12 , 13 , 14 ]. Effects of thermocapillary convection [ 15 , 16 , 17 ], as well as evaporation effects [ 18 , 19 ] and the exerted recoil pressure of the beam [ 20 ], are considered responsible according to the literature. This effect is most commonly described for lens-shaped melt pools and is already commercially used to create defined surface structures according to the Surfi-Sculpt ® process.…”