Background: Micromixers having various simple and complex microchannels is an
inevitable part of almost all the microfluidic devices and circuitries nowadays. Particularly the
metallic micromixers are very important for many chemical and process industries. Fabrication of
metallic microchannels still remains a challenging task.
Objective: The work focuses on the fabrication of microchannels of different geometries and intrinsic
features on metals. Here, an alternate approach for fabricating microchannel in metals is demonstrated
which is easy and doesn’t demand a very high level of expertise.
Method: The fabrication is carried out using Wire-Cut Electric Discharge Machine (WEDM) and
Electric Discharge Machine (EDM) and accomplished in two stages: 1) Micro-tool fabrication in
WEDM; 2) Microchannel machining in EDM. Parametric investigation of the processes is also carried
out for understanding the influence of different parameters in microfabrication.
Results: Different serpentine micromixer configurations are fabricated on copper and aluminum. Open
channel configuration of metallic micromixers of average microchannel width 400 μm is fabricated as
per the design. During micro-tool fabrication in WEDM, parametric conditions: pulse on time 25 µs,
pulse off time 6 μs, input current 1 A and wire feed rate 75 mm/min gave optimal results among the
investigated parametric combinations. During the second stage of microfabrication using EDM, the
effect of input parameters, viz. input current, pulse on time and pulse off time on the output parameters
viz. machining time, overcut, edge deviation and tool depletion are investigated. Results highlight the
importance of careful selection and control of all these process parameters for manufacturing metallic
microchannels by EDM.
Conclusion: The proposed method is able to give rise to micro-features like microchannel on metals
with reasonable ease and accuracy. The fabricated micromixers can be used for Lab on Chip (LOC),
Point of Care (POC) devices or/and microreactors. The metallic micromixers can be used to handle
various corrosive species and reagents which the conventional polymeric substrate can’t handle. Thus
it can lead to further advancement in the field of microfluidics.