Micro Manufacturing Colloquium - 22 July 2021

INJECTION MOULDING POLYMER MICRONEEDLES USING LASER ABLATED MOULDS 

Microneedle arrays contain needle-like microscopic structures which facilitate drug or vaccine delivery in a minimally invasive way. Manufacturing these micro-systems represents a real challenge and a mass production process with high volume outputs at low cost is lacking. We present a method to produce polymer microneedles using laser ablated moulds in an injection moulding process. Using a femtosecond laser, we successfully created both solid and hollow micro cavities with low tip radii in different mould materials. These moulds are afterwards used in an injection moulding process to replicate the polymer microneedles. The functionality of the manufactured hollow needles is successfully demonstrated, by injecting a controlled flow of coloured water into an agarose matrix.

OPTIMIZATION OF A MICROMIXER DESIGN BY IMPLEMENTING MICRO EDM MILLING TECHNICAL MODEL 

Development of microreactor technology, which exploits microstructured devices for realization of (bio)chemical processes, greatly benefited from development of microengineering technologies. Micromixers are essential functional components of a microreactor system. In specific applications, metallic materials are used as substrates due to their ability to withstand high pressures and harsh environmental conditions. In this context micro EDM milling is one of the adequate micromachining processes which removes material due to electrical discharges occurring between microscopic cylindrical electrode and electrically conductive workpiece. To efficiently and cost effectively employ micro EDM milling technology one needs to consider its advantages and disadvantages. In colloquium a simple technical model of micro EDM milling will be presented. To demonstrate its applicability a model geometry of a bottom grooved micromixer is investigated. To characterize particular micromixer’s design performance CFD modeling is employed. Through the design optimization campaign, by implementing the technical model, favorable micromixer designs are demonstrated and some micro EDM milling design rules are highlighted.