Highly integrable and normally open microvalve for industrial thermoplastic-based lab on PCB

Abstract

In this paper, a prototype of a highly integrable and normally-open in-line microvalve for industrial Lab on Printed Circuit Board, Lab on PCB (LoP) is described. This work is justified due to the lack of this kind of microvalves in LoPs. In addition, the proposed principle of working to close the microvalve has not been previously published. The microvalve is composed of industrial fabrication materials, that is, polymethylmethacrylate (PMMA) and Printed Circuit Board (PCB). The LoP and the microvalve share the same fabrication process, providing the characteristic of highly integrable. The procedure of fabrication of the device is based on milling for the plastic part, wet etching for the PCB, and a thermo-mechanical adhesion to perform the assembly. The actuation method is based on the increase of temperature due to the Joule effect of a copper line inside the working microchannel. The generated heat melts the PMMA microchannel and blocks it when the temperature reaches a value higher than the melting point of the plastic. The microvalve needs 3.1 A to be closed, being the time of closing 15 s with a power consumption of 440 mW.