Improvement of Directed Energy Deposition (DED) material addition rate via fluence-based parameter scaling method

Directed Energy Deposition (DED) is a metal additive manufacturing process where feedstock (metal powder in this study) is delivered to a meltpool on the surface of a metallic part simultaneously with an energy source (a laser in this study) that causes the local melting. DED process productivity is measured using the Material Addition Rate (MAR) which is a measure of the amount of material that is added to the part per interval of time, while process efficiency is measured with the powder catchment efficiency which is the ratio of powder deposited into the part and powder fed through the nozzle during the deposition cycle. If clad geometry can be maintained while deposition head feed rate is increased, then MAR is increased. As DED functionality has been integrated into industrial CNC machining centers published deposition head feed rates in literature have not kept up with machine feed rate capabilities. This research demonstrates a method of using energy and powder fluence into the meltpool to scale up deposition head feed rate in a DED equipped CNC machining center to improve MAR while maintaining part quality and geometric accuracy.