Tooling and microinjection moulding of bottom grooved micromixers

摘要

Micromixers are used in microreactor systems to mix two or more liquids in highly laminar flow. This paper deals with manufacturing process chains producing two types of bottom grooved micromixers, namely staggered herringbone micromixer (SHM) and slanted groove micromixer (SGM), which perform well in a wide range of laminar flows characterised by Reynolds number. At first, the micromixer prototypes with grooves were machined by micro EDM milling. After successful testing of the prototypes, a suitable process chain used to produce a mould insert for microinjection moulding was identified. A direct tooling approach was chosen for the generation of the tool insert, consisting of protruding features, with radii as small as 30μm, on a relatively large flat surface. Thus the selected process chain needs to address high material removal and small features. Finally, the process parameters for microinjection moulding of polystyrene (PS) were selected for mass production of micromixers.