Micro rolling fabrication of copper/SS304L micro composite channels

Fabrication of micro channels is an important aspect in the development of microfluidic devices, such as microreactors, micro heat exchangers, micro heat sinks and fuel cell bipolar plates. An ultra-thin metal foil rolling for the fabrication of micro composite channels was first proposed in this study, which is able to improve product function and reduce operational cost. Copper/SS304L composite foils with the thickness of 0.3 mm for copper and 0.1 mm for SS304L after annealing at 900 °C were used to form micro channels under different rolling reductions (0.10–0.25 mm) and velocities (7.07–35.35 mm/s), and the processing characteristics, material deformation behaviours and processing mechanisms of the rolling process were investigated. The results show that the ridges and channels are asymmetrical in all samples, while the ridges become more round with the increase of rolling reduction and the decrease of rolling velocity. For the samples with different rolling reductions, the difference between set rolling reductions and the forming depth first decreases and then increases. Besides, the micro features, including micro scratches, adhesion and smooth surfaces on the surfaces of micro channels become more significant with the increase of rolling reduction, and thus the roughness increase with increased rolling reduction. For the samples with different rolling velocities, a lower velocity would be conducive to fabricating the micro channels with a higher forming accuracy. As the rolling velocity increases, the micro scratches, adhesion and smooth surfaces on the surfaces of micro channels can be reduced during rolling process.