Researchers:
Li Cao, Susan Mantell, Dept. of Mechanical Engineering, Dennis Polla, Dept. of Electrical Engineering Project Description: MEMS fabrication techniques offer a unique solution to biomedical
applications. Using MEMS technology, an implantable micropump can be fabricated to
accurately and conveniently administer small amounts of medicine. The flow rate can be
precisely regualted by electronics that are integral to the micropump. In this project, a bulk
PZT actuated, low power, peristaltic micropump for implantable medical drug delivery systems was
designed, fabricated and tested. A silicon wafer was bulk machined to form three 30 µm
thick circular (3mm in diameter) membranes that are connected by a flow passage. To
pump fluid at 10 µL/min, the membranes are actuated at 400 Hz in a peristaltic mode.
The overall micropump size is 10mm x 4.5 mm x 0.52 mm. This design is unique because the
manufacturing process is relatively simple and the micorpump is self-priming. In this
presentation, the analytic methods behind the design will be presented. The compression ratio
of our micropump is checked to ensure that the design is self-priming. The pumped volume is
determined by electro-mechanical coupled field analysis using the Finite Element Method.
Incompessible and viscous flow analysis are applied to size the flow channels. Silicon membranes
with varied diameter adn thickness have been fabricated following MEMS techniques. Bulk PZT
plates were selected as the actuators and manually glued onto silicon membranes. These prototype
pumping chambers were tested by the actuating the bulk PZT and measured membrane deflection.
There are good agreement between membrane deflection data and analytic calculations.