A French standard (T30), that employs powder discharged for a period of 30s from a fiuidized bed as a measure of fluidity, was evaluated to determine the flowability of powder. The fluidity measurement correlated well with the dependency of powder flow on size distribution and powder chemistry. The effect of vibration on fluidity depends on size distribution; as a result, in some powders fluidity increased significantly with vibration, and in some cases the fluidity gain was marginal. Similarly, the effect of flow additives was found to be highly significant on some powders, while other powders did not respond as well. The results show that fluidity may be influenced by tribo-electric charge distribution of powder.
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