Single-track geometry prediction of direct-energy-deposition process of stainless-steel-316L with low power and slow velocity, via mathematic modeling with experimental validation Academic Article in Scopus uri icon

abstract

  • Purpose ¿ Laser-directed energy deposition is an emerging additive manufacturing technique renowned for fabricating or repairing intricate geometric components. This study aims to elucidate the criticality of input processing parameters for minimizing defects/porosity in the deposited weld bead, obtaining desired geometry with regulated contact angles and reaching or surpassing the microhardness of a forged 316L sample. Design/methodology/approach ¿ An experimental investigation applying the Taguchi design explored process parameters, including laser power, traversing speed and powder feed rate. Over 200 samples were prepared using a hybrid machine with a custom feeder mechanism, which included the development of a unit converter. Characterization of 316L powder material provided grain size and chemical composition. These inputs were packed into mathematical models whose basis was set by introducing specific energy and mass per unit length. Findings ¿ The insights revealed five optimal setups with distinct laser power levels, traversing speeds and powder feed rates. Five equations calculate the geometry and hardness of any weld track in the manufacturing approach. Originality/value ¿ Different from prior investigations that concentrated on high-power laser systems with swift work speeds, this study focuses on low-power systems (below 400 W) with reduced traversing speeds (up to 400¿mm/min), four powder-feeding nozzles and a 1¿mm laser spot diameter. Mathematical models were developed to predict bead geometry, contact angles and hardness by integrating mass per unit length (MUL) and specific energy (E) as primary variables. Five optimal configurations were identified and validated through over 200 experiments, achieving microhardness comparable to forged 316L with minimal porosity. © 2025 Emerald Publishing Limited

publication date

  • January 1, 2025