Rapid Hybrid Tooling Based on CNC- and μEDM-Milling to Fabricate Lab-on-a-Chip Systems

R. Jurischka(a), A. Schoth(a), C. Müller(a), C. Baggi(b), R. Gallera(b), H. Reinecke(a)
a: Department of Microsystems Engineering IMTEK, Laboratory for Process Technology University of Freiburg, 79110 Freiburg, Germany
b: Sarix SA, Micro EDM Technology, 6616 Losone, Switzerland

Abstract

Microfluidic devices are becoming more and more important in life science, chemical analytic, and medical areas. For these applications disposable and low cost articles are highly convenient. Polymers are ideally suited for these applications due to their material properties and their applicability for high volume production with high accuracy.

In this study, we combine the CNC-milling technology with a optimized μEDM-milling process to fabricate mould inserts made from steel, including micro and macro fluidic structures. The microfluidic structures have channel dimensions down to 18μm, aspect ratios of up to 4 and a surface roughness Ra 70 nm. Additionally, demoulding drafts of 2-6 degrees have been achieved, resulting in low demoulding forces. These tools were characterized and polymer parts were reproduced by injection moulding. The main advantage of the combination of CNC- and μEDMmilling technology is the rapid and direct structuring of tool steel for mould inserts with a 3D geometry and a long tool life time. These tools are used as mould inserts for injection moulding, enabling flexible prototyping as well as the high volume replication of polymers.