Considering mature printed circuit board processes, researches on microfluidic pumps that can be integrated into printed circuit board will provide a solution for further miniaturization and integration of microfluidic systems with low costs. The principle and structure of a printed circuit board process–based piezoelectric microfluidic pump integrated into printed circuit board are proposed and realized in this article. The printed circuit board process–based design and manufacturing technology of a piezoelectric microfluidic pump integrated into printed circuit board is researched utilizing printed circuit board as a platform. The flow characteristics of the fabricated microfluidic pump are experimentally tested. The research results show that the proposed principle and structure of the piezoelectric microfluidic pump can be fabricated utilizing mature printed circuit board process with advantages of simple structure and convenient processing. The fabricated printed circuit board process–based microfluidic pump can linearly pump in and pump out fluid with self-injection. Moreover, the flow rate and back pressure can be controlled by changing the peak-to-peak value, frequency, and phase difference of the driving voltages. The instantaneous flow rate has the pulsation property consistent with the drive voltage frequency. The proposed principle and structure are beneficial to integrate the fabricated printed circuit board process–based microfluidic pump with other microfluidic components to realize complicated microfluidic systems on printed circuit board.

For improving flow rate of multi-chamber piezoelectric pump with active valves, principle and structure of multi-chamber piezoelectric pump based on pumping unit with double circular piezoelectric unimorph actuators (CPUAs) are proposed. Double CPUAs are coaxially and symmetrically arranged on top and bottom of pump chamber and work in same frequency and phase at same time to provide driving force for pump. Two active piezoelectric valves with annular boundary are designed on left and right of pumping unit to ensure the multi-chamber piezoelectric pump bidirectionally pump fluid with high control accuracy and stop characteristics. Process compatible with printed circuit board (PCB) process is used to manufacture pump to ensure low cost. Flow rate model is established to numerically simulate flow characteristics of the pump. Pump is also experimentally tested and analyzed. Results show that proposed principle and structure can effectively improve flow rate and out pressure of multi-chamber piezoelectric pump with high control accuracy and stop characteristics of flow. Moreover, flow rate model can accurately describe its flow characteristics, which will be beneficial to design and optimize multi-chamber piezoelectric pumps with active valves. Proposed principle and structure of multi-chamber piezoelectric pumps with active valves have potential applications in complex microfluidic systems such as biochemical analysis, drug delivery and chip cooling.

Parametric simulation of multi-chamber piezoelectric pump proposed by authors shows that its flow rate is positively correlated with chamber compression ratio when height of chamber wall is not less than central deflection of circular piezoelectric unimorph actuator (CPUA). Therefore, in this paper, principle and structure of multi-chamber piezoelectric pump with novel CPUAs with three-layer structure are proposed and realized, so as to improve its chamber compression ratio, and then improve its flow rate. Its processing technology compatible with PCB processing technology is studied and its flow rate model is established. Central deflection of CPUA with three-layer structure and the flow rate characteristics are tested. Experimental results show that when the central deflection of CPUA with three-layer structure reaches the maximum value of 106.8 μm, the chamber compression ratio and flow rate of multi-chamber piezoelectric pump reach the maximum value of 50% and 3.11 mL/min, respectively. The maximum flow rate is increased by 622% compared to unimproved pump. By comparing experimental results with numerical and finite element simulation results, the realized multi-chamber piezoelectric pump has large flow rate and the established flow rate model can predict its flow rate.