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Micromachines 2018, 9(2), 73;

Micro-Dosing of Fine Cohesive Powders Actuated by Pulse Inertia Force

School of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
Author to whom correspondence should be addressed.
Received: 6 January 2018 / Revised: 2 February 2018 / Accepted: 3 February 2018 / Published: 7 February 2018
(This article belongs to the Special Issue Additive Manufacturing for Medical Applications)
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Micro-dosing of fine cohesive powders is the key technology in additive manufacturing and especially in high-potency active pharmaceutical ingredients (HPAPI). However, high accuracy micro-dosing (<5 mg) of fine cohesive powder is less trivial and still remains a challenge because it is difficult to eliminate the aggregation phenomena caused by the strong interparticle cohesive forces (in small capillaries). This paper presents a novel micro-dose method of fine cohesive powders via a pulse inertia force system. A piezoelectric actuator is used to provide a high enough pulse inertia force for a tapered glass nozzle and drive powder particles in the nozzle to be discharged from the nozzle orifice with the help of particle self-gravity. The nozzles with outlet diameters in the range of 100–2000 µm were fabricated via a glass heating process. The α-lactose monohydrate powder is used as the micro-dosing powder. The influences of the tapered nozzle outlet diameter, amplitude of the applied pulse voltage, and angle of the nozzle axis on micro-dosing mass are researched. The minimum mean dose mass is 0.6 mg for a single pulse inertia force. The coefficient of variation of dose mass, which represents the micro-dosing stability, can be controlled below 5% when the dose mass is relatively small. View Full-Text
Keywords: fine powder; micro-dosing; piezoelectric actuator; nozzle; pulse inertia force fine powder; micro-dosing; piezoelectric actuator; nozzle; pulse inertia force

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Wang, H.; Zhang, T.; Zhao, M.; Chen, R.; Wu, L. Micro-Dosing of Fine Cohesive Powders Actuated by Pulse Inertia Force. Micromachines 2018, 9, 73.

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