Additive manufacturing of microfluidic components via wax extrusion

This paper presents an innovative application of the fused deposition modeling (FDM) technique in wax printing of microfluidic structures. Preliminary experimental fabrication and characterization of printed wax ridges, as well as thermo-fluidic computational fluid dynamic (CFD)-based modeling of the printing process are presented. The 3D CFD model solves the Navier-Stokes and heat transfer equations for flowing wax and accounts of solidification as the wax cools. The CFD modeling provides fundamental understanding of the printing physics, to enable rational tuning of critical process parameters toward optimization of the ridge printing process. This wax-based printing technique uses a printing style similar to that of the polymer-based FDM 3D printing process wherein a wax extruder tip, filled with molten beeswax is translated across a printing substrate using precise computer-based motion control to create fluidic circuit positive molds at the microscale. The molds can be used to fabricate fluidic circuit components. The wax-based FDM 3D printing technique and the accompanying CFD model provide a rational design testbed for future fabrication of microfluidic components.