A PZT-driven atomizer based on a vibrating flexible membrane and a micro-machined trumpet-shaped nozzle array

This paper presents the design, and fabrication of a PZT-driven atomizer based on a flexible membrane and a micro-machined trumpet-shaped nozzle array. Tests were conducted to demonstrate that the developed atomizer can produce fine droplets. The atomizer uses a PZT bimorph plate attached to a liquid-proof HDPE membrane with a low Young's modulus to generate a pressure wave in the liquid reservoir. The trumpet-shaped micro-nozzle array is fabricated using a surface micromachining technique and an electroplating process. The fabrication process allows the use of a low resolution photomask to fabricate a high feature-sized trumpet-nozzle array. The SMD values of the ejected droplets and the flow rate of the fabricated atomizer are measured experimentally as a function of the operating frequency and the nozzle diameter for liquids of various viscosities. The relationship between the droplet size distribution and the SMD value is also explored. The experimental results show that the atomizer is capable of generating droplets with an SMD of 4.6 μ at a flow rate of 2.5 g/min. Hence, the atomizer has the potential for use in many applications.