Effect of process parameters on defects in large scale components manufactured by direct laser deposition

Direct laser deposition (DLD), implemented on the basis of a 5-axis robot manipulator, is a very flexible technique with many adjustable process parameters affecting the quality of the final product. Objects manufactured by the DLD method may contain defects significantly reducing mechanical and functional properties. This article provides an overview of possible DLD process-induced defects that were identified by increasing the density of the produced material. The following defects were identified and discussed in the current work: Lack of fusion, porosity, cracking, oxide inclusions, and metal influx. It is shown that by changing such process parameters as laser power, powder feed rate, head lift and hatch distance, it is possible to improve the quality of the cladding and substantially reduce the process-induced defects.