Experimental analysis of the influence of process parameters on the melt pool formation and stability in powder bed laser

Abstract

If the powder bed laser melting process is now widely used, the fusion process is not clearly understood yet. Particularly, it is important, formation of spatters and melt pool stability has not been analyzed.From previous works, thermo convective effects have evidenced but should be more investigated. In this article, we present new experiments to tackle these issues. First, we present the experimental setup.A high speed camera can register videos from different point of view around the laser spot and melt pool. Different process parameters can be changed: laser power, speed, gas type, material, granulometry…The fusion of the powder is registered along the track. Video analyses evidence the way the powder is fusion depending of the process paramters. They allow exhibiting the stabilization effect of a reduction of the granulometry and the decrease of speed travel. The spatters formation is discussed with the observation of a gas type or a lower power change..If the powder bed laser melting process is now widely used, the fusion process is not clearly understood yet. Particularly, it is important, formation of spatters and melt pool stability has not been analyzed.From previous works, thermo convective effects have evidenced but should be more investigated. In this article, we present new experiments to tackle these issues. First, we present the experimental setup.A high speed camera can register videos from different point of view around the laser spot and melt pool. Different process parameters can be changed: laser power, speed, gas type, material, granulometry…The fusion of the powder is registered along the track. Video analyses evidence the way the powder is fusion depending of the process paramters. They allow exhibiting the stabilization effect of a reduction of the granulometry and the decrease of speed travel. The spatters formation is discussed with the observation of a gas type or a lower power change..