Investigating build geometry characteristics during laser directed energy deposition based additive manufacturing

Laser directed energy deposition (LDED) is one of the metal additive manufacturing processes for fabricating complex shaped metallic components directly from a digital model using high power lasers and metallic powder. To fabricate components with minimum inaccuracies in build geometry and maximum build economy, optimization of process parameters is significant. In the present work, an experimental investigation is carried out to optimize LDED parameters (laser power, scanning speed, powder feed rate, rastering pattern, and build orientation) using an L9 orthogonal array as per the Taguchi design, by building an effective portion of cube geometry. The influence of input process parameters on build geometry and build economy is investigated, and grey relational (GR) analysis is carried out for multiobjective analysis. ANOVA shows that the most significant parameter influencing inaccuracy along the length, inaccuracy along the height, surface unevenness, and edge deviation error is build-orientation, while inaccuracy along the width, build time, and build fraction are largely influenced by laser energy per unit length. GR analysis shows that the build orientation is the most significant parameter. This study is important for considering build geometry and build economy during LDED.