Analysis and prediction of single laser tracks geometrical characteristics in coaxial laser cladding process

Abstract

Direct Laser Fabrication is a promising new manufacturing technology coming from laser cladding process. From a coaxial nozzle, powder is fed through a laser beam on a substrate. The powder melting and solidification processes lead to the fabrication of a part layer by layer. In this work 316L stainless steel powder is used to form laser tracks on a low carbon steel substrate. The layer geometry is an important process characteristic to control the final part of fabrication. This paper presents analytical relationships between the laser tracks geometrical characteristics (width, height, area, penetration depth) and the processing parameters (laser power P, scanning speed V and powder mass flow Q m). Three values of each processing parameters are fixed and so 27 different experiments have been made and analyzed. The validity of these results is discussed studying the correlation coefficient R, the graphical analysis of the residuals and the uncertainty evaluations. Two kinds of models are studied to predict the form and the geometrical characteristics of the single laser tracks cross sections. The first one is an analytical model in which the distribution of the powder in the feed jet is supposed to govern the laser clad geometry. Three distributions are proposed: Gaussian, uniform and polynomial. In the second model the general form of the clad cross section is supposed to be a disk due to the surface tension forces. Analytical relationships are established between the radius and the center of the disk in one hand and the process parameters in the other hand. This way we show that we can reproduce the laser track geometry in all the area experimentally explored.

Experimental characterization of laser cladding of CPM 9V on H13 tool steel for die repair applications

“…The approximation of dilution in terms of geometrical characteristics has been done in several studies [2,6,10,12,13]. Therefore, dilution zone can be defined as the region with substantial inter-mixing of the species from both the clad and substrate.…”

Microstructural evolution and bonding characteristic in multi-layer laser cladding of NiCoCr alloy on compacted graphite cast iron

“…The melt pool solidifies and a deposited layer with special performance is produced after the laser beam moves away. A laser coating of up to 2 mm could be deposited by overlapping successive tracks (Smurov et al, 2013;El Cheikh et al, 2012a), providing a way to protect the base metal from thermal shock.…”

Advances in the modeling of laser direct metal deposition

“…The typical assumptions of an analytical model are quasistationary conditions, a mathematically simple substrate shape (typically semi-infinite or thin plate), and geometrically simple melt pool boundaries, either combinations of half ellipses 34,35 (based on moving source heat theory 36,37 ) or circles 11,38,39 (assuming surface tension normal to the surface shapes the molten pool). Despite these necessary simplifications, there have been some recent informative models and ones covering the effect of powder types and laser focus points on wall layer formation [40][41][42] and on combining laser and induction heating for hybrid rapid cladding 43 stand out.…”