Interdigital transducer generated surface acoustic waves suitable for powder transport

- We proposed a novel actuator by a surface acoustic wave (SAW) for dry powder.
- We studied a highly efficient interdigital transducer (IDT) that generates a SAW.
- It was found that IDT location and shape have a big influence on the efficiency.
- We fabricated the SAW actuator with the highly efficient IDT for feeding dry powder.
- Powder (Cu: 100 μm) supply capability of the SAW actuator was about 18 mg/s.

Recently, in the electronics and pharmaceutical industries, miniature devices that can transport a tiny amount of dry powder with a particle size of 100 μm or less are desired. We therefore focused on a surface acoustic wave (SAW) device, and we experimentally studied an interdigital transducer (IDT) that generates the SAW. As a result, it was found that an IDT with a 2-mm pitch size at a 90° inclination angle, against the perpendicular direction of a piezoelectric wafer (127.8° y-rotated x-propagating LiNbO3) orientation flat, had a high efficiency of copper powder (about 100-μm particle size) transport. Then, to investigate the availability of a SAW actuator with this highly efficient IDT, we fabricated a miniature feeder (13-mm height × 18-mm width × 78-mm length) mounted with a hopper on the SAW actuator and carried out a powder supply experiment. As a result, it was found that, when 1 W of electric power was applied to the IDT of the feeder, the powder supply capability of the feeder was about 18 mg/s. From this fact, it was experimentally shown that a SAW actuator with a highly efficient IDT has a great potential to control dry powder with superior accuracy.

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