Switchable Microvalve for High-Pressure Applications

Abstract:
Microvalves are key components in microfluidic systems, enabling precise fluid control in compact architectures. Extending their operational range to high-pressure environments expands their applicability in fields such as chemical processing, biomedical analysis, and industrial sensing. This work presents the design, simulation, fabrication, and testing of a switchable microvalve capable of operating under pressures up to 200 bar. Finite element method simulations (FEMS) were conducted to evaluate different membrane materials and thicknesses, leading to the selection of polyimide for its favorable mechanical and thermal properties. A first concept revealed significant stress concentration under moderate pressures, making it unsuitable for high-pressure use. To address this, the microvalve cavity geometry was redesigned to include a dual-curvature support structure—one concave and one convex—optimized via FEMS to minimize and uniformly distribute von Mises stress (vMs) across the membrane. Key parameters, including cavity radius, cavity height, and membrane thickness, were studied. The improved microvalve was fabricated in glass using Selective Laser-induced Etching (SLE) and a custom metal housing was machined. Experimental validation confirmed the microvalve’s capability to withstand inlet pressures up to 200 bar without membrane failure, with potential for further pressure capacity. The new design effectively redistributes the vMs in the membrane, significantly improving reliability and fatigue resistance. Additionally, the architecture minimizes dead volume and it is compatible with a variety of actuation methods, with potential for automation in future implementations.