Powder-based Directed Energy Deposition (DED-LB/P) is a well-established technique for additive manufacturing, coating, and repair of metallic components. The use of powder as feedstock offers flexibility and material versatility but is constrained by high costs and limited deposition efficiency compared to wire. Despite modern nozzle designs reaching powder utilization rates over 90%, auxiliary process times still lead to significant material losses, particularly in discontinuous deposition strategies, and increase contamination risks for the handling system and workpiece. This issue is highly relevant for high-speed processes such as EHLA3D, in which the laser beam is repeatedly interrupted during numerous acceleration and deceleration phases. Existing powder switching mechanisms rely on mechanical actuation, limiting their switching speed and long-term reliability.

In this work, a novel fluidic powder switch is developed, featuring an innovative design that enables near-instantaneous switching of a powder flow. Unlike conventional solutions, the fluid-based mechanism eliminates the need for mechanical switching elements in the powder conveying line, reducing system wear and enabling direct integration into a DED nozzle. The proposed system enables three key functionalities: (i) rapid redirection of a powder gas stream between the nozzle outlet and a collection container, (ii) rapid switching between discrete powder mass flow levels, and (iii) fast toggling between different powder feedstock materials. Its performance is systematically assessed by analyzing switching times, system inertia, and the stability of the powder gas jet. Experimental validation in EHLA3D confirms substantial improvements in powder utilization efficiency compared to state-of-the-art, making it a promising solution for advanced DED systems.