Research Projects

Laser based Directed Energy Deposition (L-DED) process is a very versatile process which can be used for additive manufacturing, surface engineering and refurbishment applications. The parts produced using L-DED are not suitable to be used directly because of poor surface finish and dimensional accuracies, and hence essentially require secondary machining operation. The machining of L-DED components as compared to wrought alloys is a challenging task because of presence of microstructural inhomogeneity, unfused material and random residual porosity which makes machining unstable. The evolution of microstructure in L-DED process depends upon cooling rates which are governed by L-DED process parameters. The first objective of this project is to correlate cooling rates and microstructure with machining performance of L-DED Inconel 718 shafts. Laser polishing (controlled partial remelting of top deposited layer) has been found to improve surface roughness, but form accuracies still required machining. The second part of this project is to study the feasibility of hybrid finishing process for L-DED Inconel 718 shafts where laser polishing and machining are to be carried out simultaneously to achieve better surface roughness and form accuracies in a single step. The effect of heat treatment of L-DED Inconel 718 shafts on machinability is also the subject of investigation of this project. Apart from Inconel 718, machining of a hard coating (consisting of tungsten carbide particles) deposited using L-DED process is also to be investigated.