One-step ultra-fast production of millifluidic devices: Technical proof-of-concept

Microfluidic and millifluidic systems are increasingly used for chemical and biological analysis.Thermoplastic polymers offer a practical alternative to glass and silicon.They are inexpensive, easy to shape, and suitable for disposable devices.However, most polymer microfluidic chips are still produced in two steps: machining the channels, then bonding a cover plate.This workflow increases alignment constraints, exposes open channels to contamination, and lengthens production time.This study presents a one-step method based on transmission laser welding (TLW) applied to closed-cell thermoplastic foams.The laser heats and collapses the foam locally, causing the cell walls to fuse and form a channel while welding a transparent cover at the same time.The process creates a sealed microchannel without moving the parts between steps.We examine the feasibility of this method and study how laser output power affects channel dimensions.The approach also enables the creation of X and Y junctions by using several fast passes to control melting at the intersections.The channels obtained show smooth internal walls and a near-cylindrical cross-section.Their size can be adjusted through the laser parameters.This method offers a simple and clean way to prototype polymer millifluidic or microfluidic devices.