An automatic measurement system for evaluating powder flowability based on the vibrating capillary method has been studied experimentally. The vibration amplitude was controlled by a computer, and the vibration acceleration and the mass of particles discharged from the capillary were obtained by digital processing. The measurement time was 2 min and the amount of the powder required for each measurement was less than a few grams. To characterize the dynamic powder flowability, evaluation factors were developed. A series of experiments was conducted using powders with mass median diameters from 5.2 to 58.2 pm, showing that this measurement system can fully evaluate the powder flowability. (c) 2008 Elsevier B.V. All rights reserved.