Feasibility Study of Extrusion Based Additive Manufacturing Process for Creating Biomimetic Microchannel Network

Abstract

Fabrication of micro-scaled 3-dimensional channels to produce a vascular network of capillaries through a sacrificial material approach has been achieved using traditional methods such as casting, lithography, etc. Casting produces a randomly aligned capillary network which provides no predominant direction for flow; this depends on how the sacrificial material settles during the process. Lithography is not known to produce encapsulated channels in a 3D matrix and generally works over the surface or exposed area of the material. Adopting an extrusion-based additive manufacturing method assists the production of aligned capillaries predominantly in the direction of extrusion. This work attempts to characterize the degree of alignment of the fibers of sacrificial material (sugar) in an extruded matrix of PDMS (Sylgard 184™). The goal of this research work is to understand the alignment of sacrificial material fibers in a viscous two-phase extrudable material. Finding an appropriate material combination is under the future scope of this research. Experiments were conducted for identifying a suitable composition of sugar fibers and resin that can be extruded at different pressures to obtain an observable network of fibers under the microscope. Multiple methods of fiber mixing were explored for uniform dispersion and a standard operating procedure for the fiber-silicon extrusion has been proposed. Images of extruded samples for different process parameters were analyzed statistically to quantify the alignment of fibers. A full factorial analysis of experimental design was performed to establish the effect of extrusion pressure and convergence angle at extrusion on the alignment of extruded fibers.