Over the last couple of years, additive manufacturing (AM) of metals has taken a big leap towards industrialization. The use of AM is not only limited to rapid prototyping, but it is also growing faster into actual production facilities. Laser Metal Directed Energy Deposition (LMDED) is a novel manufacturing method that has many advantages over conventional manufacturing methods. It introduces low heat input as compared to traditional welding processes. Hence it is popular for repairing of sensitive components. LMDED is also used for adding features to semi-finished or finished products. Also, the small parts with complex geometries can be manufactured using this method. But for certain process conditions LMDED produces cracks. This is the main concern associated with this process.

The aim of this research is to develop a computational model for the Laser metal powder directed energy deposition (LMPDED) process of Alloy 718 to understand and predict the cracking susceptibility. The effect of most influential process parameters such as laser power, scanning speed, and powder feed rate were studied through the thermo-mechanical modelling. The experimental trial was conducted for a set of parameters to validate the deformation. GOM Atos 3D scanning equipment was used to measure the deformation experimentally. The effect of thermal conditions on thermal stresses and cracks were studied. Also, the metallography study is carried out to measure the re-melt depth. The effect of dwell time on thermal stresses was also studied.

There is a good agreement between experimental and simulation results. It was observed that crack susceptible parameters induce higher thermal stresses.