Users of powder-fed directed energy deposition system often face several challenges associated with conventional powder delivery sub-systems. In addition to the high cost of wasted powder, it can be difficult to plan for the amount of material being deposited when some of the dispensed powder is not captured in the melt pool. This work studies the effectiveness of a vibration-actuated powder dispensing system using a nozzle with a small capillary opening. The opening is sized so that particle contact forces arrest powder flow when the vibration actuator is turned off. The relative effects of vibration frequency, vibration acceleration, nozzle size and nozzle inclination are compared with the goal of having the output mass flow rate monotonically change with one of these parameters. For the materials and parameters explored in this study, nozzle inclination is found to have the largest effect on mass flow rate output and has the desired monotonically changing relationship.