Research On The Correlations Of Melt Pool Geometry And Energy Efficiency During Laser Metal Deposition Process

Laser Metal Deposition(LMD)is a form of laser-based Additive Manufacturing process which uses intense laser energy to melt feed stocks(metallic powders/wires)onto the metallic substrate base layer-by-layer deposition to form functional prototypes.LMD is majorly applied in automobile,aerospace,etc.In an LMD process,energy efficiency is low and melt pool is highly dynamic,making it difficult to predict the clad shape.This compromises the quality of the fabricated components.Previous studies have shown little convergence on the role process parameters play in achieving energy efficient process and quality component including optimal parameters combinations.In this work,models based on mass balance and energy conservation are developed to predict the melt pool temperature and clad bead height for single clad layer beads of 316 L stainless steel.The models relate three main process parameters;laser power,powder feed rate and scanning speed to melt pool geometry in order to predict the temperature and bead height.Using orthogonal array design,a three factors and four levels method was chosen to perform an experiment.The results were analyzed using statistical software MINITAB.The theoretical and experimental results show good agreement.The results show that energy efficiency and melt pool geometry are affected by process parameters.A relationship is also traced between energy efficiency and melt pool geometry.Clad height tends to increase with increasing energy efficiency.In addition,energy efficient process is the one for which process parameters are optimally combined.Laser power between(800~1000W),higher powder feed rates(28~30g/min)and lower scanning speed(550~650mm/min)provide better parameters combinations having energy efficiency range 7.45 ~ 9.95%.Finally,an in-depth analysis of process parameters and temperature on melt pool geometry is done and recommendations are given.